title: Manchu language

text: Manchu has twenty consonants, shown in the table using each phoneme's representation in the IPA, followed by its romanization in italics. was rare and found mostly in loanwords and onomatopoeiae, such as "pak pik" ('pow pow'). Historically, appears to have been common, but changed over time to . was also found mostly in loanwords and onomatopoeiae and there was no single letter in the Manchu alphabet to represent it, but rather a digraph of the letters for and . is usually transcribed with a digraph "ni", and has thus often been considered a sequence of phonemes rather than a phoneme of its own, though work in Tungusic historical linguistics suggests that the Manchu palatal nasal has a very long history as a single segment, and so it is shown here as phonemic.


title: Manchu language

text: Early Western descriptions of Manchu phonology labeled Manchu "b" as "soft p", Manchu "d" as "soft t", and Manchu "g" as "soft k", whereas Manchu "p" was "hard p", "t" was "hard t", and "k" was "hard k". This suggests that the phonological contrast between the so-called voiced series ("b, d, j, g") and the voiceless series ("p, t, c, k") in Manchu as it was spoken during the early modern era was actually one of aspiration (as shown here) or tenseness, as in Mandarin.


title: Manchu language

text: In this vowel system, the "neutral" vowels ("i" and "u") were free to occur in a word with any other vowel or vowels. The lone front vowel ("e", but generally pronounced like Mandarin [ɤ] ) never occurred in a word with either of the regular back vowels ("o" and "a"), but because the rules of vowel harmony are not perceptible with diphthongs, the diphthong "eo" occurs in some words, i.e. "deo", "younger brother", "geo", "a mare", "jeo", "department", "leole", "to discuss", "leose", "building", and "šeole", "to embroider", "to collect".


title: Manchu language

text: The relatively rare vowel transcribed "ū" (pronounced ) was usually found as a back vowel; however, in some cases, it was found occurring along with the front vowel "e". Much disputation exists over the exact pronunciation of "ū". , a German sinologist and Manchurist, proposes that it was pronounced as a front rounded vowel initially, but a back unrounded vowel medially. William Austin suggests that it was a mid-central rounded vowel. The modern Xibe pronounce it identically to "u".


title: Manchu language

text: There are altogether eighteen diphthongs and six triphthongs. The diphthongs are "ai", "ao", "ei", "eo", "ia", "ie", "ii", "io", "iu", "oi", "oo", "ua", "ue", "ui", "uo", "ūa", "ūe", "ūi", and "ūo". The triphthongs are "ioa", "ioo" (which is pronounced as ), "io(w)an", "io(w)en", "ioi" (), and "i(y)ao", and they exist in Chinese loanwords.


title: Manchu language

text: Manchu absorbed a large number of non-native sounds into the language from Chinese. There were special symbols used to represent the vowels of Chinese loanwords. These sounds are believed to have been pronounced as such, as they never occurred in native words. Among these, was the symbol for the high unrounded vowel (customarily romanized with a "y", /ɨ/) found in words such as "sy" (Buddhist temple) and "Sycuwan" (Sichuan); and the triphthong "ioi" which is used for the Chinese "ü" sound. Chinese affricates were also represented with consonant symbols that were only used with loanwords such as in the case of "dzengse" (orange) (Chinese: "chéngzi") and "tsun" (inch) (Chinese: "cùn"). In addition to the vocabulary that was borrowed from Chinese, the Manchu language also had a large amount of loanwords from other languages such as Mongolian, for example the words "morin" (horse) and "temen" (camel).


title: Manchu language

text: The vowel harmony found in the Manchu language was traditionally described in terms of the philosophy of the "I Ching". Syllables with front vowels were described as being as "yin" syllables whereas syllables with back vowels were called "yang" syllables. The reasoning behind this was that the language had a kind of sound symbolism where front vowels represented feminine objects or ideas and the back vowels represented masculine objects or ideas. As a result, there were a number of word pairs in the language in which changing the vowels also changed the gender of the word. For example, the difference between the words "hehe" (woman) and "haha" (man) or "eme" (mother) and "ama" (father) was essentially a contrast between the front vowel, [e], of the feminine and the back vowel, [a], of the masculine counterpart.


title: Manchu language

text: The Manchu language uses the Manchu script, which was derived from the traditional Mongol script, which in turn was based on the vertically written pre-Islamic Uyghur script. Manchu is now usually romanized according to the transliteration system employed by Jerry Norman in his "Comprehensive Manchu-English Dictionary" (2013). The Jurchen language, which is ancestral to Manchu, used the Jurchen script, which is derived from the Khitan script, which in turn was derived from Chinese characters. There is no relation between the Jurchen script and the Manchu script.


title: Manchu language

text: Chinese characters, employed as phonograms, can also be used to transliterate Manchu. All the Manchu vowels and the syllables commencing with a consonant are represented by single Chinese characters as are also the syllables terminating in "i, n, ng" and "o"; but those ending in "r, k, s, t, p, I, m" are expressed by the union of the sounds of two characters, there being no Mandarin syllables terminating with these consonants. Thus the Manchu syllable "am" is expressed by the Chinese characters "a mù", and the word "Manchu" is, in the Kangxi Dictionary, spelled as "mă ā ān zhū wū".


title: Manchu language

text: Mongols learned their script as a syllabary, dividing the syllables into twelve different classes, based on the final phonemes of the syllables, all of which ended in vowels. The Manchus followed the same syllabic method when learning Manchu script, also with syllables divided into twelve different classes based on the finals phonemes of the syllables. Today, the opinion on whether it is alphabet or syllabic in nature is still split between different experts. In China, it is considered syllabic and Manchu is still taught in this manner. The alphabetic approach is used mainly by foreigners who want to learn the language. Studying Manchu script as a syllabary takes a longer time.


title: Manchu language

text: Despite the alphabetic nature of its script, Manchu was not taught phoneme per letter like western languages are; Manchu children were taught to memorize all the syllables in the Manchu language separately as they learned to write, like Chinese characters. To paraphrase Meadows 1849,Manchus when learning, instead of saying l, a—la; l, o—lo; &c., were taught at once to say la, lo, &c. Many more syllables than are contained in their syllabary might have been formed with their letters, but they were not accustomed to arrange them otherwise. They made, for instance, no such use of the consonants l, m, n, and r, as westerners do; hence if the Manchu letters s, m, a, r, t, are joined in that order a Manchu would not able to pronounce them as English speaking people pronounce the word 'smart'.However this was in 1849, and more research should be done on the current teaching methods used in the PRC.


title: Ball

text: A ball is a round object (usually spherical, but can sometimes be ovoid) with several uses. It is used in ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. Balls can also be used for simpler activities, such as catch or juggling. Balls made from hard-wearing materials are used in engineering applications to provide very low friction bearings, known as ball bearings. Black-powder weapons use stone and metal balls as projectiles.


title: Ball

text: Although many types of balls are today made from rubber, this form was unknown outside the Americas until after the voyages of Columbus. The Spanish were the first Europeans to see the bouncing rubber balls (although solid and not inflated) which were employed most notably in the Mesoamerican ballgame. Balls used in various sports in other parts of the world prior to Columbus were made from other materials such as animal bladders or skins, stuffed with various materials.


title: Ball

text: As balls are one of the most familiar spherical objects to humans, the word "ball" may refer to or describe spherical or near-spherical objects.


title: Ball

text: "Ball" is used metaphorically sometimes to denote something spherical or spheroid, e.g., armadillos and human beings curl up into a ball, making a fist into a ball.


title: Ball

text: The first known use of the word "ball" in English in the sense of a globular body that is played with was in 1205 in "" in the phrase, "" The word came from the Middle English "bal" (inflected as "ball-e, -es", in turn from Old Norse "böllr" (pronounced ; compare Old Swedish "baller", and Swedish "boll") from Proto-Germanic "ballu-z" (whence probably Middle High German "bal, ball-es", Middle Dutch "bal"), a cognate with Old High German "ballo, pallo", Middle High German balle from Proto-Germanic "*ballon" (weak masculine), and Old High German "ballâ, pallâ", Middle High German "balle", Proto-Germanic "*ballôn" (weak feminine). No Old English representative of any of these is known. (The answering forms in Old English would have been "beallu, -a, -e"—compare "bealluc, ballock".) If "ball-" was native in Germanic, it may have been a cognate with the Latin "foll-is" in sense of a "thing blown up or inflated." In the later Middle English spelling "balle" the word coincided graphically with the French "balle" "ball" and "bale" which has hence been erroneously assumed to be its source. French "balle" (but not "boule") is assumed to be of Germanic origin, itself, however. In Ancient Greek the word πάλλα ("palla") for "ball" is attested besides the word σφαίρα ("sfaíra"), "sphere".


title: Ball

text: A ball, as the essential feature in many forms of gameplay requiring physical exertion, must date from the very earliest times. A rolling object appeals not only to a human baby, but to a kitten and a puppy. Some form of game with a ball is found portrayed on Egyptian monuments, and is played among aboriginal tribes at the present day. In Homer, Nausicaa was playing at ball with her maidens when Odysseus first saw her in the land of the Phaeacians (Od. vi. 100). And Halios and Laodamas performed before Alcinous and Odysseus with ball play, accompanied with dancing (Od. viii. 370). The most ancient balls in Eurasia have been discovered in Karasahr, China and are 3.000 years old. They were made of hair-filled leather.


title: Ball

text: Among the ancient Greeks, games with balls (σφαῖραι) were regarded as a useful subsidiary to the more violent athletic exercises, as a means of keeping the body supple, and rendering it graceful, but were generally left to boys and girls. Of regular rules for the playing of ball games, little trace remains, if there were any such. The names in Greek for various forms, which have come down to us in such works as the Ὀνομαστικόν of Julius Pollux, imply little or nothing of such; thus, ἀπόρραξις ("aporraxis") only means the putting of the ball on the ground with the open hand, οὐρανία ("ourania"), the flinging of the ball in the air to be caught by two or more players; φαινίνδα ("phaininda") would seem to be a game of catch played by two or more, where feinting is used as a test of quickness and skill. Pollux (i. x. 104) mentions a game called episkyros (ἐπίσκυρος), which has often been looked on as the origin of football. It seems to have been played by two sides, arranged in lines; how far there was any form of "goal" seems uncertain. It was impossible to produce a ball that was perfectly spherical; children usually made their own balls by inflating pig's bladders and heating them in the ashes of a fire to make them rounder, although Plato (fl. 420s BC – 340s BC) described "balls which have leather coverings in twelve pieces".


title: Ball

text: Among the Romans, ball games were looked upon as an adjunct to the bath, and were graduated to the age and health of the bathers, and usually a place (sphaeristerium) was set apart for them in the baths (thermae). There appear to have been three types or sizes of ball, the pila, or small ball, used in catching games, the paganica, a heavy ball stuffed with feathers, and the follis, a leather ball filled with air, the largest of the three. This was struck from player to player, who wore a kind of gauntlet on the arm. There was a game known as trigon, played by three players standing in the form of a triangle, and played with the follis, and also one known as harpastum, which seems to imply a "scrimmage" among several players for the ball. These games are known to us through the Romans, though the names are Greek.


title: Ball

text: The various modern games played with a ball or balls and subject to rules are treated under their various names, such as polo, cricket, football, etc.


title: Public key certificate

text: In cryptography, a public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the validity of a public key. The certificate includes information about the key, information about the identity of its owner (called the subject), and the digital signature of an entity that has verified the certificate's contents (called the issuer). If the signature is valid, and the software examining the certificate trusts the issuer, then it can use that key to communicate securely with the certificate's subject. In email encryption, code signing, and e-signature systems, a certificate's subject is typically a person or organization. However, in Transport Layer Security (TLS) a certificate's subject is typically a computer or other device, though TLS certificates may identify organizations or individuals in addition to their core role in identifying devices. TLS, sometimes called by its older name Secure Sockets Layer (SSL), is notable for being a part of HTTPS, a protocol for securely browsing the web.


title: Public key certificate

text: In a typical public-key infrastructure (PKI) scheme, the certificate issuer is a certificate authority (CA), usually a company that charges customers to issue certificates for them. By contrast, in a web of trust scheme, individuals sign each other's keys directly, in a format that performs a similar function to a public key certificate.


title: Public key certificate

text: The most common format for public key certificates is defined by X.509. Because X.509 is very general, the format is further constrained by profiles defined for certain use cases, such as Public Key Infrastructure (X.509) as defined in .


title: Public key certificate

text: The Transport Layer Security (TLS) protocol – as well as its outdated predecessor, the Secure Sockets Layer (SSL) protocol – ensures that the communication between a client computer and a server is secure. The protocol requires the server to present a digital certificate, proving that it is the intended destination. The connecting client conducts certification path validation, ensuring that:


title: Public key certificate

text: The "Subject" field of the certificate must identify the primary hostname of the server as the "Common Name". A certificate may be valid for multiple hostnames (e.g., a domain and its subdomains). Such certificates are commonly called "Subject Alternative Name (SAN) certificates" or "Unified Communications Certificates (UCC)". These certificates contain the Subject Alternative Name field, though many CAs also put them into the "Subject Common Name" field for backward compatibility. If some of the hostnames contain an asterisk (*), a certificate may also be called a wildcard certificate.


title: Public key certificate

text: Once the certification path validation is successful, the client can establish an encrypted connection with the server.


title: Public key certificate

text: Internet-facing servers, such as public web servers, must obtain their certificates from a trusted, public certificate authority (CA).


title: Public key certificate

text: Client certificates authenticate the client connecting to a TLS service, for instance to provide access control. Because most services provide access to individuals, rather than devices, most client certificates contain an email address or personal name rather than a hostname. In addition, the certificate authority that issues the client certificate is usually the service provider to which client connects because it is the provider that needs to perform authentication. Some service providers even offer free SSL certificates as part of their packages.


title: Public key certificate

text: While most web browsers support client certificates, the most common form of authentication on the Internet is a username and password pair. Client certificates are more common in virtual private networks (VPN) and Remote Desktop Services, where they authenticate devices.


title: Public key certificate

text: In accordance with the S/MIME protocol, email certificates can both establish the message integrity and encrypt messages. To establish encrypted email communication, the communicating parties must have their digital certificates in advance. Each must send the other one digitally signed email and opt to import the sender's certificate.


title: Public key certificate

text: Some publicly trusted certificate authorities provide email certificates, but more commonly S/MIME is used when communicating within a given organization, and that organization runs its own CA, which is trusted by participants in that email system.


title: Public key certificate

text: A self-signed certificate is a certificate with a subject that matches its issuer, and a signature that can be verified by its own public key.


title: Public key certificate

text: Self-signed certificates have their own limited uses. They have full trust value when the issuer and the sole user are the same entity. For example, the Encrypting File System on Microsoft Windows issues a self-signed certificate on behalf of the encrypting user and uses it to transparently decrypt data on the fly. The digital certificate chain of trust starts with a self-signed certificate, called a "root certificate", "trust anchor", or "trust root". A certificate authority self-signs a root certificate to be able to sign other certificates.


title: Public key certificate

text: An intermediate certificate has a similar purpose to the root certificate – its only use is to sign other certificates. However, an intermediate certificate is not self-signed. A root certificate or another intermediate certificate needs to sign it.


title: Public key certificate

text: An end-entity or leaf certificate is any certificate that cannot sign other certificates. For instance, TLS/SSL server and client certificates, email certificates, code signing certificates, and qualified certificates are all end-entity certificates.


title: Public key certificate

text: These are some of the most common fields in certificates. Most certificates contain a number of fields not listed here. Note that in terms of a certificate's X.509 representation, a certificate is not "flat" but contains these fields nested in various structures within the certificate.


title: Public key certificate

text: This is an example of a decoded SSL/TLS certificate retrieved from SSL.com's website. The issuer's common name (CN) is shown as codice_1, identifying this as an Extended Validation (EV) certificate. Validated information about the website's owner (SSL Corp) is located in the codice_2 field. The codice_3 field contains a list of domain names covered by the certificate. The codice_4 and codice_5 fields show all appropriate uses.


title: Public key certificate

text: In the European Union, (advanced) electronic signatures on legal documents are commonly performed using digital signatures with accompanying identity certificates. However, only qualified electronic signatures (which require using a qualified trust service provider and signature creation device) are given the same power as a physical signature.


title: Public key certificate

text: In the X.509 trust model, a certificate authority (CA) is responsible for signing certificates. These certificates act as an introduction between two parties, which means that a CA acts as a trusted third party. A CA processes requests from people or organizations requesting certificates (called subscribers), verifies the information, and potentially signs an end-entity certificate based on that information. To perform this role effectively, a CA needs to have one or more broadly trusted root certificates or intermediate certificates and the corresponding private keys. CAs may achieve this broad trust by having their root certificates included in popular software, or by obtaining a cross-signature from another CA delegating trust. Other CAs are trusted within a relatively small community, like a business, and are distributed by other mechanisms like Windows Group Policy.


title: Public key certificate

text: Certificate authorities are also responsible for maintaining up-to-date revocation information about certificates they have issued, indicating whether certificates are still valid. They provide this information through Online Certificate Status Protocol (OCSP) and/or Certificate Revocation Lists (CRLs). Some of the larger certificate authorities in the market include IdenTrust, DigiCert, and Sectigo.


title: Public key certificate

text: Some major software contain a list of certificate authorities that are trusted by default. This makes it easier for end-users to validate certificates, and easier for people or organizations that request certificates to know which certificate authorities can issue a certificate that will be broadly trusted. This is particularly important in HTTPS, where a web site operator generally wants to get a certificate that is trusted by nearly all potential visitors to their web site.


title: Public key certificate

text: The policies and processes a provider uses to decide which certificate authorities their software should trust are called root programs. The most influential root programs are:


title: Public key certificate

text: Browsers other than Firefox generally use the operating system's facilities to decide which certificate authorities are trusted. So, for instance, Chrome on Windows trusts the certificate authorities included in the Microsoft Root Program, while on macOS or iOS, Chrome trusts the certificate authorities in the Apple Root Program. Edge and Safari use their respective operating system trust stores as well, but each is only available on a single OS. Firefox uses the Mozilla Root Program trust store on all platforms.


title: Public key certificate

text: The Mozilla Root Program is operated publicly, and its certificate list is part of the open source Firefox web browser, so it is broadly used outside Firefox. For instance, while there is no common Linux Root Program, many Linux distributions, like Debian, include a package that periodically copies the contents of the Firefox trust list, which is then used by applications.


title: Public key certificate

text: Root programs generally provide a set of valid purposes with the certificates they include. For instance, some CAs may be considered trusted for issuing TLS server certificates, but not for code signing certificates. This is indicated with a set of trust bits in a root certificate storage system.


title: Public key certificate

text: The most common use of certificates is for HTTPS-based web sites. A web browser validates that an HTTPS web server is authentic, so that the user can feel secure that his/her interaction with the web site has no eavesdroppers and that the web site is who it claims to be. This security is important for electronic commerce. In practice, a web site operator obtains a certificate by applying to a certificate authority with a certificate signing request. The certificate request is an electronic document that contains the web site name, company information and the public key. The certificate provider signs the request, thus producing a public certificate. During web browsing, this public certificate is served to any web browser that connects to the web site and proves to the web browser that the provider believes it has issued a certificate to the owner of the web site.


title: Public key certificate

text: As an example, when a user connects to codice_6 with their browser, if the browser does not give any certificate warning message, then the user can be theoretically sure that interacting with codice_6 is equivalent to interacting with the entity in contact with the email address listed in the public registrar under "example.com", even though that email address may not be displayed anywhere on the web site. No other surety of any kind is implied. Further, the relationship between the purchaser of the certificate, the operator of the web site, and the generator of the web site content may be tenuous and is not guaranteed. At best, the certificate guarantees uniqueness of the web site, provided that the web site itself has not been compromised (hacked) or the certificate issuing process subverted.


title: Public key certificate

text: A certificate provider can opt to issue three types of certificates, each requiring its own degree of vetting rigor. In order of increasing rigor (and naturally, cost) they are: Domain Validation, Organization Validation and Extended Validation. These rigors are loosely agreed upon by voluntary participants in the CA/Browser Forum.


title: Public key certificate

text: A certificate provider will issue a domain-validated (DV) certificate to a purchaser if the purchaser can demonstrate one vetting criterion: the right to administratively manage the affected DNS domain(s).


title: Public key certificate

text: A certificate provider will issue an organization validation (OV) class certificate to a purchaser if the purchaser can meet two criteria: the right to administratively manage the domain name in question, and perhaps, the organization's actual existence as a legal entity. A certificate provider publishes its OV vetting criteria through its certificate policy.


title: Public key certificate

text: To acquire an Extended Validation (EV) certificate, the purchaser must persuade the certificate provider of its legal identity, including manual verification checks by a human. As with OV certificates, a certificate provider publishes its EV vetting criteria through its certificate policy.


title: Public key certificate

text: Until 2019, major browsers such as Chrome and Firefox generally offered users a visual indication of the legal identity when a site presented an EV certificate. This was done by showing the legal name before the domain, and a bright green color to highlight the change. Most browsers deprecated this feature providing no visual difference to the user on the type of certificate used. This change followed security concerns raised by forensic experts and successful attempts to purchase EV certificates to impersonate famous organizations, proving the inefficiency of these visual indicators and highlighting potential abuses.


title: Public key certificate

text: A web browser will give no warning to the user if a web site suddenly presents a different certificate, even if that certificate has a lower number of key bits, even if it has a different provider, and even if the previous certificate had an expiry date far into the future. Where certificate providers are under the jurisdiction of governments, those governments may have the freedom to order the provider to generate any certificate, such as for the purposes of law enforcement. Subsidiary wholesale certificate providers also have the freedom to generate any certificate.


title: Public key certificate

text: All web browsers come with an extensive built-in list of trusted root certificates, many of which are controlled by organizations that may be unfamiliar to the user. Each of these organizations is free to issue any certificate for any web site and have the guarantee that web browsers that include its root certificates will accept it as genuine. In this instance, end users must rely on the developer of the browser software to manage its built-in list of certificates and on the certificate providers to behave correctly and to inform the browser developer of problematic certificates. While uncommon, there have been incidents in which fraudulent certificates have been issued: in some cases, the browsers have detected the fraud; in others, some time passed before browser developers removed these certificates from their software.


title: Public key certificate

text: The list of built-in certificates is also not limited to those provided by the browser developer: users (and to a degree applications) are free to extend the list for special purposes such as for company intranets. This means that if someone gains access to a machine and can install a new root certificate in the browser, that browser will recognize websites that use the inserted certificate as legitimate.


title: Public key certificate

text: For provable security, this reliance on something external to the system has the consequence that any public key certification scheme has to rely on some special setup assumption, such as the existence of a certificate authority.


title: Public key certificate

text: In spite of the limitations described above, certificate-authenticated TLS is considered mandatory by all security guidelines whenever a web site hosts confidential information or performs material transactions. This is because, in practice, in spite of the weaknesses described above, web sites secured by public key certificates are still more secure than unsecured http:// web sites.


title: Public key certificate

text: The National Institute of Standards and Technology (NIST) Computer Security Division provides guidance documents for public key certificates:


title: Cardiac output

text: In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols formula_1, formula_2, or formula_3, is the volumetric flow rate of the heart's pumping output: that is, the volume of blood being pumped by both ventricles of the heart, per unit time (usually measured per minute). Cardiac output (CO) is the product of the heart rate (HR), i.e. the number of heartbeats per minute (bpm), and the stroke volume (SV), which is the volume of blood pumped from the left ventricle per beat; thus giving the formula:


title: Cardiac output

text: Values for cardiac output are usually denoted as L/min. For a healthy individual weighing 70 kg, the cardiac output at rest averages about 5 L/min; assuming a heart rate of 70 beats/min, the stroke volume would be approximately 70 mL.


title: Cardiac output

text: Because cardiac output is related to the quantity of blood delivered to various parts of the body, it is an important component of how efficiently the heart can meet the body's demands for the maintenance of adequate tissue perfusion. Body tissues require continuous oxygen delivery which requires the sustained transport of oxygen to the tissues by systemic circulation of oxygenated blood at an adequate pressure from the left ventricle of the heart via the aorta and arteries. Oxygen delivery (DO mL/min) is the resultant of blood flow (cardiac output CO) times the blood oxygen content (CaO). Mathematically this is calculated as follows: oxygen delivery = cardiac output × arterial oxygen content, giving the formula:


title: Cardiac output

text: With a resting cardiac output of 5 L/min, a 'normal' oxygen delivery is around 1 L/min. The amount/percentage of the circulated oxygen consumed (VO) per minute through metabolism varies depending on the activity level but at rest is circa 25% of the DO. Physical exercise requires a higher than resting-level of oxygen consumption to support increased muscle activity. In the case of heart failure, actual CO may be insufficient to support even simple activities of daily living; nor can it increase sufficiently to meet the higher metabolic demands stemming from even moderate exercise.


title: Cardiac output

text: Cardiac output is a global blood flow parameter of interest in hemodynamics, the study of the flow of blood. The factors affecting stroke volume and heart rate also affect cardiac output. The figure at the right margin illustrates this dependency and lists some of these factors. A detailed hierarchical illustration is provided in a subsequent figure.


title: Cardiac output

text: There are many methods of measuring CO, both invasively and non-invasively; each has advantages and drawbacks as described below.


title: Cardiac output

text: The function of the heart is to drive blood through the circulatory system in a cycle that delivers oxygen, nutrients and chemicals to the body's cells and removes cellular waste. Because it pumps out whatever blood comes back into it from the venous system, the quantity of blood returning to the heart effectively determines the quantity of blood the heart pumps out – its cardiac output, "Q". Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:


title: Cardiac output

text: In standardizing what CO values are considered to be within normal range independent of the size of the subject's body, the accepted convention is to further index equation () using body surface area (BSA), giving rise to the Cardiac index (CI). This is detailed in equation () below.


title: Cardiac output

text: There are a number of clinical methods to measure cardiac output, ranging from direct intracardiac catheterization to non-invasive measurement of the arterial pulse. Each method has advantages and drawbacks. Relative comparison is limited by the absence of a widely accepted "gold standard" measurement. Cardiac output can also be affected significantly by the phase of respiration – intra-thoracic pressure changes influence diastolic filling and therefore cardiac output. This is especially important during mechanical ventilation, in which cardiac output can vary by up to 50% across a single respiratory cycle. Cardiac output should therefore be measured at evenly spaced points over a single cycle or averaged over several cycles.


title: Cardiac output

text: Invasive methods are well accepted, but there is increasing evidence that these methods are neither accurate nor effective in guiding therapy. Consequently, the focus on development of non-invasive methods is growing.


title: Cardiac output

text: This method uses ultrasound and the Doppler effect to measure cardiac output. The blood velocity through the heart causes a Doppler shift in the frequency of the returning ultrasound waves. This shift can then be used to calculate flow velocity and volume, and effectively cardiac output, using the following equations:


title: Cardiac output

text: Being non-invasive, accurate and inexpensive, Doppler ultrasound is a routine part of clinical ultrasound; it has high levels of reliability and reproducibility, and has been in clinical use since the 1960s.


title: Cardiac output

text: Echocardiography is a non-invasive method of quantifying cardiac output using ultrasound. Two-dimensional (2D) ultrasound and Doppler measurements are used together to calculate cardiac output. 2D measurement of the diameter (d) of the aortic annulus allows calculation of the flow cross-sectional area (CSA), which is then multiplied by the VTI of the Doppler flow profile across the aortic valve to determine the flow volume per beat (stroke volume, SV). The result is then multiplied by the heart rate (HR) to obtain cardiac output. Although used in clinical medicine, it has a wide test-retest variability. It is said to require extensive training and skill, but the exact steps needed to achieve clinically adequate precision have never been disclosed. 2D measurement of the aortic valve diameter is one source of noise; others are beat-to-beat variation in stroke volume and subtle differences in probe position. An alternative that is not necessarily more reproducible is the measurement of the pulmonary valve to calculate right-sided CO. Although it is in wide general use, the technique is time-consuming and is limited by the reproducibility of its component elements. In the manner used in clinical practice, precision of SV and CO is of the order of ±20%.


title: Cardiac output

text: Ultrasonic Cardiac Output Monitor (USCOM) uses continuous wave Doppler to measure the Doppler flow profile VTI. It uses anthropometry to calculate aortic and pulmonary valve diameters and CSAs, allowing right-sided and left-sided "Q" measurements. In comparison to the echocardiographic method, USCOM significantly improves reproducibility and increases sensitivity of the detection of changes in flow. Real-time, automatic tracing of the Doppler flow profile allows beat-to-beat right-sided and left-sided "Q" measurements, simplifying operation and reducing the time of acquisition compared to conventional echocardiography. USCOM has been validated from 0.12 L/min to 18.7 L/min in new-born babies, children and adults. The method can be applied with equal accuracy to patients of all ages for the development of physiologically rational haemodynamic protocols. USCOM is the only method of cardiac output measurement to have achieved equivalent accuracy to the implantable flow probe. This accuracy has ensured high levels of clinical use in conditions including sepsis, heart failure and hypertension.


title: Cardiac output

text: The Transoesophageal Doppler includes two main technologies; transoesophageal echocardiogram—which is primarily used for diagnostic purposes, and oesophageal Doppler monitoring—which is primarily used for the clinical monitoring of cardiac output. The latter uses continuous wave Doppler to measure blood velocity in the descending thoracic aorta. An ultrasound probe is inserted either orally or nasally into the oesophagus to mid-thoracic level, at which point the oesophagus lies alongside the descending thoracic aorta. Because the transducer is close to the blood flow, the signal is clear. The probe may require re-focussing to ensure an optimal signal. This method has good validation, is widely used for fluid management during surgery with evidence for improved patient outcome, and has been recommended by the UK's National Institute for Health and Clinical Excellence (NICE). Oesophageal Doppler monitoring measures the velocity of blood and not true "Q", therefore relies on a nomogram based on patient age, height and weight to convert the measured velocity into stroke volume and cardiac output. This method generally requires patient sedation and is accepted for use in both adults and children.


title: Cardiac output

text: Pulse pressure (PP) methods measure the pressure in an artery over time to derive a waveform and use this information to calculate cardiac performance. However, any measure from the artery includes changes in pressure associated with changes in arterial function, for example compliance and impedance. Physiological or therapeutic changes in vessel diameter are assumed to reflect changes in "Q". PP methods measure the combined performance of the heart and the blood vessels, thus limiting their application for measurement of "Q". This can be partially compensated for by intermittent calibration of the waveform to another "Q" measurement method then monitoring the PP waveform. Ideally, the PP waveform should be calibrated on a beat-to-beat basis. There are invasive and non-invasive methods of measuring PP.


title: Cardiac output

text: In 1967, the Czech physiologist Jan Peňáz invented and patented the volume clamp method of measuring continuous blood pressure. The principle of the volume clamp method is to dynamically provide equal pressures, on either side of an artery wall. By clamping the artery to a certain volume, inside pressure—intra-arterial pressure—balances outside pressure—finger cuff pressure. Peñáz decided the finger was the optimal site to apply this volume clamp method. The use of finger cuffs excludes the device from application in patients without vasoconstriction, such as in sepsis or in patients on vasopressors.


title: Cardiac output

text: In 1978, scientists at BMI-TNO, the research unit of Netherlands Organisation for Applied Scientific Research at the University of Amsterdam, invented and patented a series of additional key elements that make the volume clamp work in clinical practice. These methods include the use of modulated infrared light in the optical system inside the sensor, the lightweight, easy-to-wrap finger cuff with velcro fixation, a new pneumatic proportional control valve principle, and a set point strategy for the determining and tracking the correct volume at which to clamp the finger arteries—the Physiocal system. An acronym for physiological calibration of the finger arteries, this Physiocal tracker was found to be accurate, robust and reliable.


title: Cardiac output

text: The Finapres methodology was developed to use this information to calculate arterial pressure from finger cuff pressure data. A generalised algorithm to correct for the pressure level difference between the finger and brachial sites in patients was developed. This correction worked under all of the circumstances it was tested in—even when it was not designed for it—because it applied general physiological principles. This innovative brachial pressure waveform reconstruction method was first implemented in the Finometer, the successor of Finapres that BMI-TNO introduced to the market in 2000.


title: Cardiac output

text: The availability of a continuous, high-fidelity, calibrated blood pressure waveform opened up the perspective of beat-to-beat computation of integrated haemodynamics, based on two notions: pressure and flow are inter-related at each site in the arterial system by their so-called characteristic impedance. At the proximal aortic site, the 3-element Windkessel model of this impedance can be modelled with sufficient accuracy in an individual patient with known age, gender, height and weight. According to comparisons of non-invasive peripheral vascular monitors, modest clinical utility is restricted to patients with normal and invariant circulation.


title: Cardiac output

text: Invasive PP monitoring involves inserting a manometer pressure sensor into an artery—usually the radial or femoral artery—and continuously measuring the PP waveform. This is generally done by connecting the catheter to a signal processing device with a display. The PP waveform can then be analysed to provide measurements of cardiovascular performance. Changes in vascular function, the position of the catheter tip or damping of the pressure waveform signal will affect the accuracy of the readings. Invasive PP measurements can be calibrated or uncalibrated.


title: Cardiac output

text: ( AG, Munich, Germany) and PulseCO (LiDCO Ltd, London, England) generate continuous "Q" by analysing the arterial PP waveform. In both cases, an independent technique is required to provide calibration of continuous "Q" analysis because arterial PP analysis cannot account for unmeasured variables such as the changing compliance of the vascular bed. Recalibration is recommended after changes in patient position, therapy or condition.


title: Cardiac output

text: In PiCCO, transpulmonary thermodilution, which uses the Stewart-Hamilton principle but measures temperatures changes from central venous line to a central arterial line, i.e., the femoral or axillary arterial line, is used as the calibrating technique. The "Q" value derived from cold-saline thermodilution is used to calibrate the arterial PP contour, which can then provide continuous "Q" monitoring. The PiCCO algorithm is dependent on blood pressure waveform morphology (mathematical analysis of the PP waveform), and it calculates continuous "Q" as described by Wesseling and colleagues. Transpulmonary thermodilution spans right heart, pulmonary circulation and left heart, allowing further mathematical analysis of the thermodilution curve and giving measurements of cardiac filling volumes (), intrathoracic blood volume and extravascular lung water. Transpulmonary thermodilution allows for less invasive "Q" calibration but is less accurate than PA thermodilution and requires a central venous and arterial line with the accompanied infection risks.


title: Cardiac output

text: In LiDCO, the independent calibration technique is lithium chloride dilution using the Stewart-Hamilton principle. Lithium chloride dilution uses a peripheral vein and a peripheral arterial line. Like PiCCO, frequent calibration is recommended when there is a change in Q. Calibration events are limited in frequency because they involve the injection of lithium chloride and can be subject to errors in the presence of certain muscle relaxants. The PulseCO algorithm used by LiDCO is based on pulse power derivation and is not dependent on waveform morphology.


title: Cardiac output

text: FloTrac/Vigileo (Edwards Lifesciences) is an uncalibrated, haemodynamic monitor based on pulse contour analysis. It estimates cardiac output ("Q") using a standard arterial catheter with a manometer located in the femoral or radial artery. The device consists of a high-fidelity pressure transducer, which, when used with a supporting monitor (Vigileo or EV1000 monitor), derives left-sided cardiac output ("Q") from a sample of arterial pulsations. The device uses an algorithm based on the Frank–Starling law of the heart, which states pulse pressure (PP) is proportional to stroke volume (SV). The algorithm calculates the product of the standard deviation of the arterial pressure (AP) wave over a sampled period of 20 seconds and a vascular tone factor (Khi, or χ) to generate stroke volume. The equation in simplified form is: formula_9, or, formula_10. Khi is designed to reflect arterial resistance; compliance is a multivariate polynomial equation that continuously quantifies arterial compliance and vascular resistance. Khi does this by analyzing the morphological changes of arterial pressure waveforms on a bit-by-bit basis, based on the principle that changes in compliance or resistance affect the shape of the arterial pressure waveform. By analyzing the shape of said waveforms, the effect of vascular tone is assessed, allowing the calculation of SV. "Q" is then derived using equation (). Only perfused beats that generate an arterial waveform are counted for in HR.


title: Cardiac output

text: This system estimates Q using an existing arterial catheter with variable accuracy. These arterial monitors do not require intracardiac catheterisation from a pulmonary artery catheter. They require an arterial line and are therefore invasive. As with other arterial waveform systems, the short set-up and data acquisition times are benefits of this technology. Disadvantages include its inability to provide data regarding right-sided heart pressures or mixed venous oxygen saturation. The measurement of Stroke Volume Variation (SVV), which predicts volume responsiveness is intrinsic to all arterial waveform technologies. It is used for managing fluid optimisation in high-risk surgical or critically ill patients. A physiologic optimization program based on haemodynamic principles that incorporates the data pairs SV and SVV has been published.


title: Cardiac output

text: Arterial monitoring systems are unable to predict changes in vascular tone; they estimate changes in vascular compliance. The measurement of pressure in the artery to calculate the flow in the heart is physiologically irrational and of questionable accuracy, and of unproven benefit. Arterial pressure monitoring is limited in patients off-ventilation, in atrial fibrillation, in patients on vasopressors, and in those with a dynamic autonomic system such as those with sepsis.


title: Cardiac output

text: Pressure Recording Analytical Method (PRAM), estimates "Q" from the analysis of the pressure wave profile obtained from an arterial catheter—radial or femoral access. This PP waveform can then be used to determine "Q". As the waveform is sampled at 1000 Hz, the detected pressure curve can be measured to calculate the actual beat-to-beat stroke volume. Unlike FloTrac, neither constant values of impedance from external calibration, nor form pre-estimated in vivo or in vitro data, are needed.


title: Cardiac output

text: PRAM has been validated against the considered gold standard methods in stable condition and in various haemodynamic states. It can be used to monitor pediatric and mechanically supported patients.


title: Cardiac output

text: Generally monitored haemodynamic values, fluid responsiveness parameters and an exclusive reference are provided by PRAM: Cardiac Cycle Efficiency (CCE). It is expressed by a pure number ranging from 1 (best) to -1 (worst) and it indicates the overall heart-vascular response coupling. The ratio between heart performance and consumed energy, represented as CCE "stress index", can be of paramount importance in understanding the patient's present and future courses.


title: Cardiac output

text: Impedance cardiography (often abbreviated as ICG, or Thoracic Electrical Bioimpedance (TEB)) measures changes in electrical impedance across the thoracic region over the cardiac cycle. Lower impedance indicates greater intrathoracic fluid volume and blood flow. By synchronizing fluid volume changes with the heartbeat, the change in impedance can be used to calculate stroke volume, cardiac output and systemic vascular resistance.


title: Cardiac output

text: Both invasive and non-invasive approaches are used. The reliability and validity of the non-invasive approach has gained some acceptance, although there is not complete agreement on this point. The clinical use of this approach in the diagnosis, prognosis and therapy of a variety of diseases continues.


title: Cardiac output

text: Ultrasound dilution (UD) uses body-temperature normal saline (NS) as an indicator introduced into an extracorporeal loop to create an atrioventricular (AV) circulation with an ultrasound sensor, which is used to measure the dilution then to calculate cardiac output using a proprietary algorithm. A number of other haemodynamic variables, such as total end-diastole volume (TEDV), central blood volume (CBV) and active circulation volume (ACVI) can be calculated using this method.


title: Cardiac output

text: The UD method was firstly introduced in 1995. It was extensively used to measure flow and volumes with extracorporeal circuit conditions, such as ECMO and Haemodialysis, leading more than 150 peer reviewed publications. UD has now been adapted to intensive care units (ICU) as the COstatus device.


title: Cardiac output

text: The UD method is based on ultrasound indicator dilution. Blood ultrasound velocity (1560–1585 m/s) is a function of total blood protein concentration—sums of proteins in plasma and in red blood red cells—and temperature. Injection of body-temperature normal saline (ultrasound velocity of saline is 1533 m/s) into a unique AV loop decreases blood ultrasound velocity, and produces dilution curves.


title: Cardiac output

text: UD requires the establishment of an extracorporeal circulation through its unique AV loop with two pre-existing arterial and central venous lines in ICU patients. When the saline indicator is injected into the AV loop, it is detected by the venous clamp-on sensor on the loop before it enters the patient's heart's right atrium. After the indicator traverses the heart and lung, the concentration curve in the arterial line is recorded and displayed on the COstatus HCM101 Monitor. Cardiac output is calculated from the area of the concentration curve using the Stewart-Hamilton equation. UD is a non-invasive procedure, requiring only a connection to the AV loop and two lines from a patient. UD has been specialised for application in pediatric ICU patients and has been demonstrated to be relatively safe although invasive and reproducible.


title: Cardiac output

text: Electrical cardiometry is a non-invasive method similar to Impedance cardiography; both methods measure thoracic electrical bioimpedance (TEB). The underlying model differs between the two methods; Electrical cardiometry attributes the steep increase of TEB beat-to-beat to the change in orientation of red blood cells. Four standard ECG electrodes are required for measurement of cardiac output. Electrical Cardiometry is a method trademarked by Cardiotronic, Inc., and shows promising results in a wide range of patients. It is currently approved in the US for use in adults, children and babies. Electrical cardiometry monitors have shown promise in postoperative cardiac surgical patients, in both haemodynamicially stable and unstable cases.


title: Cardiac output

text: Velocity-encoded phase contrast Magnetic resonance imaging (MRI) is the most accurate technique for measuring flow in large vessels in mammals. MRI flow measurements have been shown to be highly accurate compared to measurements made with a beaker and timer, and less variable than the Fick principle and thermodilution.


title: Cardiac output

text: Velocity-encoded MRI is based on the detection of changes in the phase of proton precession. These changes are proportional to the velocity of the protons' movement through a magnetic field with a known gradient. When using velocity-encoded MRI, the result is two sets of images, one for each time point in the cardiac cycle. One is an anatomical image and the other is an image in which the signal intensity in each pixel is directly proportional to the through-plane velocity. The average velocity in a vessel, i.e., the aorta or the pulmonary artery, is quantified by measuring the average signal intensity of the pixels in the cross-section of the vessel then multiplying by a known constant. The flow is calculated by multiplying the mean velocity by the cross-sectional area of the vessel. This flow data can be used in a flow-versus-time graph. The area under the flow-versus-time curve for one cardiac cycle is the stroke volume. The length of the cardiac cycle is known and determines heart rate; "Q" can be calculated using equation (). MRI is typically used to quantify the flow over one cardiac cycle as the average of several heart beats. It is also possible to quantify the stroke volume in real-time on a beat-for-beat basis.


title: Cardiac output

text: While MRI is an important research tool for accurately measuring "Q", it is currently not clinically used for haemodynamic monitoring in emergency or intensive care settings. , cardiac output measurement by MRI is routinely used in clinical cardiac MRI examinations.


title: Cardiac output

text: The dye dilution method is done by rapidly injecting a dye, indocyanine green, into the right atrium of the heart. The dye flows with the blood into the aorta. A probe is inserted into the aorta to measure the concentration of the dye leaving the heart at equal time intervals [0, "T"] until the dye has cleared. Let "c"("t)" be the concentration of the dye at time "t". By dividing the time intervals from [0, "T"] into subintervals Δ"t", the amount of dye that flows past the measuring point during the subinterval from formula_11 to formula_12 is:


title: Cardiac output

text: where the amount of dye injected formula_19 is known, and the integral can be determined using the concentration readings.


title: Cardiac output

text: The dye dilution method is one of the most accurate methods of determining cardiac output during exercise. The error of a single calculation of cardiac output values at rest and during exercise is less than 5%. This method does not allow measurement of 'beat to beat' changes, and requires a cardiac output that is stable for approximately 10 s during exercise and 30 s at rest.


title: Cardiac output

text: Cardiac output is primarily controlled by the oxygen requirement of tissues in the body. In contrast to other pump systems, the heart is a demand pump that does not regulate its own output. When the body has a high metabolic oxygen demand, the metabolically controlled flow through the tissues is increased, leading to a greater flow of blood back to the heart, leading to higher cardiac output.


title: Cardiac output

text: The capacitance, also known as compliance, of the arterio-vascular channels that carry the blood also controls cardiac output. As the body's blood vessels actively expand and contract, the resistance to blood flow decreases and increases respectively. Thin-walled veins have about eighteen times the capacitance of thick-walled arteries because they are able to carry more blood by virtue of being more distensible.


title: Cardiac output

text: From this formula, it is clear the factors affecting stroke volume and heart rate also affect cardiac output. The figure to the right illustrates this dependency and lists a few of these factors. A more detailed hierarchical illustration is provided in a subsequent figure.


title: Cardiac output

text: Equation () reveals HR and SV to be the primary determinants of cardiac output Q. A detailed representation of these factors is illustrated in the figure to the right. The primary factors that influence HR are autonomic innervation plus endocrine control. Environmental factors, such as electrolytes, metabolic products, and temperature are not shown. The determinants of SV during the cardiac cycle are the contractility of the heart muscle, the degree of preload of myocardial distention prior to shortening and the afterload during ejection. Other factors such as electrolytes may be classified as either positive or negative inotropic agents.


title: Cardiac output

text: When "Q" increases in a healthy but untrained individual, most of the increase can be attributed to an increase in heart rate (HR). Change of posture, increased sympathetic nervous system activity, and decreased parasympathetic nervous system activity can also increase cardiac output. HR can vary by a factor of approximately 3—between 60 and 180 beats per minute—while stroke volume (SV) can vary between , a factor of only 1.7.


title: Cardiac output

text: Diseases of the cardiovascular system are often associated with changes in "Q", particularly the pandemic diseases hypertension and heart failure. Increased "Q" can be associated with cardiovascular disease that can occur during infection and sepsis. Decreased "Q" can be associated with cardiomyopathy and heart failure. Sometimes, in the presence of ventricular disease associated with dilatation, EDV may vary. An increase in EDV could counterbalance LV dilatation and impaired contraction. From equation (), the resulting cardiac output Q may remain constant. The ability to accurately measure "Q" is important in clinical medicine because it provides for improved diagnosis of abnormalities and can be used to guide appropriate management.


title: Cardiac output

text: Ejection fraction (EF) is a parameter related to SV. EF is the fraction of blood ejected by the left ventricle (LV) during the contraction or ejection phase of the cardiac cycle or systole. Prior to the start of systole, during the filling phase (diastole), the LV is filled with blood to the capacity known as end diastolic volume (EDV). During systole, the LV contracts and ejects blood until it reaches its minimum capacity known as end systolic volume (ESV). It does not completely empty. The following equations help translate the effect of EF and EDV on cardiac output Q, via SV.


title: Cardiac output

text: Cardiac input (CI) is the inverse operation of cardiac output. As cardiac output implies the volumetric expression of ejection fraction, cardiac input implies the volumetric injection fraction (IF).


title: Cardiac output

text: In all resting mammals of normal mass, CO value is a linear function of body mass with a slope of 0.1 L/(min kg). Fat has about 65% of oxygen demand per mass in comparison to other lean body tissues. As a result, the calculation of normal CO value in an obese subject is more complex; a single, common "normal" value of SV and CO for adults cannot exist. All blood flow parameters have to be indexed. It is accepted convention to index them by the body surface area, BSA [m], by DuBois & DuBois Formula, a function of height and weight:


title: Cardiac output

text: The resulting indexed parameters are stroke index (SI) and cardiac index (CI). Stroke index, measured in mL/beat/m, is defined as


title: Cardiac output

text: The CO equation () for indexed parameters then changes to the following.The normal range for these indexed blood flow parameters are between 35 and 65 mL/beat/m for SI and between 2.5 and 4 L/(min m) for CI.


title: Cardiac output

text: Combined cardiac output is the sum of the outputs of the right and left sides of the heart. It is a useful measurement in fetal circulation, where cardiac outputs from both sides of the heart work partly in parallel by the foramen ovale and ductus arteriosus, which directly supply the systemic circulation.


title: Cardiac output

text: The Fick principle, first described by Adolf Eugen Fick in 1870, assumes the rate of oxygen consumption is a function of the rate of blood flow and the rate of oxygen picked up by the red blood cells. Application of the Fick principle involves calculating the oxygen consumed over time by measuring the oxygen concentration of venous blood and arterial blood. "Q" is calculated from these measurements as follows:


title: Cardiac output

text: While considered to be the most accurate method of measuring "Q", the Fick method is invasive and requires time for sample analysis, and accurate oxygen consumption samples are difficult to acquire. There have been modifications to the Fick method where respiratory oxygen content is measured as part of a closed system and the consumed oxygen is calculated using an assumed oxygen consumption index, which is then used to calculate "Q". Other variations use inert gases as tracers and measure the change in inspired and expired gas concentrations to calculate "Q" (Innocor, Innovision A/S, Denmark).


title: Cardiac output

text: The calculation of the arterial and venous oxygen content of the blood is a straightforward process. Almost all oxygen in the blood is bound to hæmoglobin molecules in the red blood cells. Measuring the content of hæmoglobin in the blood and the percentage of saturation of hæmoglobin—the oxygen saturation of the blood—is a simple process and is readily available to physicians. Each gram of haemoglobin can carry 1.34 mL of O; the oxygen content of the blood—either arterial or venous—can be estimated using the following formula:


title: Cardiac output

text: The indicator method was further developed by replacing the indicator dye with heated or cooled fluid. Temperature changes rather than dye concentration are measured at sites in the circulation; this method is known as thermodilution. The pulmonary artery catheter (PAC) introduced to clinical practice in 1970, also known as the Swan-Ganz catheter, provides direct access to the right heart for thermodilution measurements. Continuous, invasive, cardiac monitoring in intensive care units has been mostly phased out. The PAC remains useful in right-heart study done in cardiac catheterisation laboratories.


title: Cardiac output

text: The PAC is balloon tipped and is inflated, which helps "sail" the catheter balloon through the right ventricle to occlude a small branch of the pulmonary artery system. The balloon is then deflated. The PAC thermodilution method involves the injection of a small amount (10 mL) of cold glucose at a known temperature into the pulmonary artery and measuring the temperature a known distance away using the same catheter with temperature sensors set apart at a known distance.


title: Cardiac output

text: The historically significant Swan-Ganz multi-lumen catheter allows reproducible calculation of cardiac output from a measured time-temperature curve, also known as the thermodilution curve. Thermistor technology enabled the observations that low CO registers temperature change slowly and high CO registers temperature change rapidly. The degree of temperature change is directly proportional to the cardiac output. In this unique method, three or four repeated measurements or passes are usually averaged to improve accuracy. Modern catheters are fitted with heating filaments that intermittently heat up and measure the thermodilution curve, providing serial "Q" measurements. These instruments average measurements over 2–9 minutes depending on the stability of the circulation, and thus do not provide continuous monitoring.


title: Cardiac output

text: PAC use can be complicated by arrhythmias, infection, pulmonary artery rupture and damage to the right heart valve. Recent studies in patients with critical illnesses, sepsis, acute respiratory failure and heart failure suggest that use of the PAC does not improve patient outcomes. This clinical ineffectiveness may relate to its poor accuracy and sensitivity, which have been demonstrated by comparison with flow probes across a sixfold range of "Q" values. Use of PAC is in decline as clinicians move to less invasive and more accurate technologies for monitoring hæmodynamics.


title: De'Aaron Fox

text: De'Aaron Martez Fox (born December 20, 1997) is an American professional basketball player for the Sacramento Kings of the National Basketball Association (NBA). He played college basketball for the Kentucky Wildcats before being selected 5th overall by the Kings in the 2017 NBA draft.


title: De'Aaron Fox

text: Fox attended Cypress Lakes High School in Katy, Texas. As a junior, he averaged 23.8 points, 6.1 rebounds, and 3.5 assists per game. During the summer, Fox d Houston Hoops on the Nike Elite Youth Basketball League Circuit (EYBL) where he earned EYBL first-team honors. On November 29, Fox scored 31 points, 12 rebounds, and 6 assists in a 68–53 victory over MacArthur. On December 28, Fox put up 31 points and 6 assists in a 91–81 victory against Jay M. Robinson High School. As a senior, Fox averaged 32.1 points, 7.6 rebounds, and 4.1 assists per game. In January 2016, Fox was named a McDonald's All-American and played in the 2016 McDonald's All-American Game on March 30. In April, Fox played in the 2016 Jordan Brand Classic, leading the East team to a 131–117 win while earning Co-MVP honors alongside Kentucky teammate Malik Monk. Fox then competed at the Nike Hoop Summit Games. He made the 2015–16 USA Men's Basketball Men's Junior Team in September 2015. He was also invited to the NBPA Top 100 camp. Throughout his high school career, Fox led Cypress Lakes to three state playoff appearances including a regional final appearance his senior year, and twice scored 50 points in a single game.


title: De'Aaron Fox

text: Fox was the nation's second best point guard behind Lonzo Ball. He was rated as a five-star ranked and ranked the consensus No. 6 overall recruit in the Class of 2016 by the four main recruiting services: Rivals, ESPN, and 247Sports.


title: De'Aaron Fox

text: He committed to Kentucky on November 12, 2015, live on ESPNU. He chose Kentucky over Kansas, Louisville, and LSU.


title: De'Aaron Fox

text: On November 13, 2016, Fox recorded 21 points and 3 assists during a 93–69 victory over Canisius College at the Bluegrass Showcase. Six days later, he posted 16 points and 6 assists to defeat Duquesne University, 93–69. In a game against Arizona State on November 28, he recorded a triple double with 14 points, 11 rebounds, and 10 assists; this made Fox only the second Wildcat in the history of Kentucky basketball to record one after Chris Mill in 1988. On January 7, 2017, Fox scored 27 points to go along with 6 assists in a 97–71 victory over Arkansas. He tallied 21 points and 5 assists to defeat Mississippi State, 88–81, on January 17. On February 18 that year, Fox scored 16 points and dished out 5 assists to help the Wildcats defeat the Georgia Bulldogs. On March 4, Fox scored 19 points in a 71–63 win over Texas A&M. Kentucky would go on to defeat Georgia in the quarterfinals and Alabama in the semi-finals. On March 12, Fox scored 18 points in an 82–65 win over Arkansas in the SEC tournament in addition earning SEC Tournament MVP honors. On March 17, Fox scored 19 points and 3 assists to defeat Northern Kentucky University in the first round of the NCAA tournament. On March 19, Fox scored 14 points to defeat Wichita State 65–62 in the second round of the NCAA Tournament. On March 24, In a Sweet 16 matchup against the UCLA Bruins, Fox scored 39 points to advance the Kentucky Wildcats to the Elite Eight game. On March 26, Fox only scored 13 points in a 75–73 loss to the North Carolina Tar Heels.


title: De'Aaron Fox

text: At the conclusion of his freshman season, Fox announced that he would forgo his final three years of collegiate eligibility and enter the 2017 NBA draft.


title: De'Aaron Fox

text: On June 22, 2017, Fox was selected with the fifth overall pick in the 2017 NBA draft by the Sacramento Kings. On July 8, 2017, he signed his rookie scale contract with the Kings. During four games of the 2017 NBA Summer League, Fox averaged 11.8 points, 3 assists and 2.3 steals while playing 21.3 minutes per game. Fox made his NBA debut for the Kings in their season opener on October 18, 2017, against the Houston Rockets, where he scored 14 points, 4 rebounds, and 5 assist in 24-plus minutes in a 105–100 loss. On October 23, 2017, Fox recorded a career-high 19 points, 4 assist, 5 rebounds, and 3 steals in a 117–115 loss against the Phoenix Suns. On December 8, 2017, he scored 14 points, 4 assist and 2 steals in a 116–109 win against the New Orleans Pelicans. On January 6, 2018, Fox recorded 18 points and 7 assist in a 106–98 victory over the Denver Nuggets. On January 25, 2018, Fox scored 14 points, 4 assist and a putback slam dunk with 3.3 seconds left giving the Sacramento Kings the lead in an 89–88 win over the Miami Heat. On January 28, 2018, Fox scored a season-high 26 points, going 6–6 from three-point range in a 15-point loss to the San Antonio Spurs. On February 14, Fox was named Lonzo Ball's replacement for the Rising Stars Challenge.


title: De'Aaron Fox

text: On November 1, 2018, during a 146–115 win over the Atlanta Hawks, Fox notched his first career triple-double with 31 points, 10 rebounds, and 15 assists to bring the Kings to a 6–3 record, becoming the only player after LeBron James in 2005 to score a 30-point triple double before the age of 21. Fox drastically improved during the 2018–2019 season. Not only did he improve in every major statistical category (Including his points per game from 11.6 to 17.3 and assists per game from 4.4 to 7.3), He also finished top 3 and was nominated for the NBA Most Improved Player Award, finishing second to Pascal Siakam.


title: De'Aaron Fox

text: On July 31, 2020, Fox scored a career-high 39 points in a 129–120 loss to the San Antonio Spurs. This was the Kings’ first game in the Orlando bubble, returning from a 4-month hiatus due to the COVID-19 pandemic.


title: De'Aaron Fox

text: On November 25, 2020, Fox signed a contract extension with the Kings. On February 8, 2021, Fox was named Western Conference Player of the Week for the first time in his career averaging 31 Points & nearly 9 assists while winning all 4 games on the first week of February. On March 26, 2021, Fox scored a career-high 44 points on 16-of-22 from the field in a 141–119 victory over the Golden State Warriors. On March 29, 2021, Fox was once again named Player of the Week for the second time during Week 14. Fox averaged nearly 37 points & 5 assists per game while shooting 64% from the field over the 4 games, all ending in victories for the Kings.


title: De'Aaron Fox

text: On March 5, 2022, Fox tied his career-high with 44 points on 18-for-31 shooting in a 114–113 loss against the Dallas Mavericks. On March 12, Fox had 41 points and a season-high 11 assists in a 134–125 loss against the Utah Jazz.


title: De'Aaron Fox

text: On November 5, 2022, Fox put up 37 points, alongside a buzzer-beating, game-winning three, in a 126–123 overtime win over the Orlando Magic.


title: De'Aaron Fox

text: Listed at and , Fox has primarily played the point guard position throughout his career. He is left-handed.


title: De'Aaron Fox

text: Coming out of Kentucky, Fox was highly regarded among scouts for his quickness, speed, and athleticism. These attributes combined make Fox one of the most dangerous players on the fast break and driving to the rim. Fox is often considered to be the fastest player in the NBA. Fox himself stated in 2018 "If we’re talking about from baseline to baseline with the ball in my hands, I’m definitely the fastest person in the league."


title: De'Aaron Fox

text: Fox is a high end finisher at the rim, being able to use his body control and leaping ability to finish layups and draw fouls and often using his speed and quickness to blow by defenders. Fox is considered to be a poor 3-point shooter, as during the 2019–2020 NBA season, Fox shot a career low 29.2% shooting percentage from three.


title: De'Aaron Fox

text: Fox has also demonstrated good passing ability, averaging around seven assists per game. Fox generates most of his assists running the pick and roll and the fast break.


title: De'Aaron Fox

text: On defense, Fox can be exploited by bigger guards because of his small frame, but can intercept passes and makes quick rotations due to his elite quickness and nearly 6-foot 7 inch wingspan.


title: De'Aaron Fox

text: Fox was born to his parents Aaron and Lorainne Harris-Fox and has one brother named Quentin Fox. Fox goes by the nicknames “Fox”, “Swipa”, and “Swipa da Fox”. Fox chose the number zero at Kentucky because he “fears no one”, giving his original number five to teammate Malik Monk. According to his high school coach, Fox would come to school at 6 AM and practice in the gym every morning. Fox would sleep on the couch almost every night and play the "NBA 2K" video game series. This, according to his father, is one of the reasons he has developed into the player that he is today.


title: De'Aaron Fox

text: Fox is also a fan of the "Dragon Ball Z" anime series and states that Vegeta is his favorite character. In 2017, Fox sported "Dragon Ball Z" inspired Nike shoes in game.


title: De'Aaron Fox

text: In February 2022, Fox was the subject of criticism after he shut down his personal NFT project “SwipaTheFox”, with more than $1.5 million in unpaid investment to approximately 100,000 investors. Fox explained his decision in a Twitter thread, wherein he claimed he wasn't satisfied with the quality of the project so far and was shutting it down until the end of the NBA season, but did not answer critics who demanded a return of their investment.


title: Spanish Navy

text: The Spanish Navy or officially, the Armada, is the maritime branch of the Spanish Armed Forces and one of the oldest active naval forces in the world. The Spanish Navy was responsible for a number of major historic achievements in navigation, the most famous being the discovery of America and the first global circumnavigation by Elcano. For several centuries, it played a crucial logistical role in the expansion and consolidation of the Spanish Empire, and defended a vast trade network across the Atlantic Ocean between the Americas and Europe, and the Manila Galleon across the Pacific Ocean between the Philippines and the Americas.


title: Spanish Navy

text: The Spanish Navy was the most powerful maritime force in the world from the late 15th century to the early 18th century. In the early 19th century, with the loss of most of its empire, Spain transitioned to a smaller fleet but maintained a major shipbuilding industry which produced important technical innovations. The Spanish Navy built and operated the first military submarines, made important contributions in the development of destroyer warships, and again achieved a first global circumnavigation, this time by an ironclad vessel.


title: Spanish Navy

text: The roots of the modern Spanish navy date back to before the unification of Spain. By the late Middle Ages, the two principal kingdoms that would later combine to form Spain, Aragon and Castile, had developed powerful fleets. Aragon possessed the third largest navy in the late medieval Mediterranean, although its capabilities were exceeded by those of Venice and (until overtaken in the 15th century by those of Aragon) Genoa. In the 14th and 15th centuries, these naval capabilities enabled Aragon to assemble the largest collection of territories of any European power in the Mediterranean, encompassing the Balearics, Sardinia, Sicily, southern Italy and, briefly, the Duchy of Athens.


title: Spanish Navy

text: Castile meanwhile used its naval capacities to conduct its Reconquista operations against the Moors, capturing Cádiz in 1232 and also to help the French Crown against England in the Hundred Years' War. In 1375, a Castilian fleet destroyed a large English fleet at Bourgneuf, and Castilian ships raided the English coast. As Castile developed long-lasting trade relationships with towns in the Low Countries of the Netherlands and Flanders, the English Channel virtually became the "Spanish Channel." In 1402, a Castilian expedition led by Juan de Bethencourt conquered the Canary Islands for Henry III of Castile. In 1419, the Castilians defeated the German Hanseatic League at sea and excluded them from the Bay of Biscay.


title: Spanish Navy

text: In the 15th century, Castile entered into a race of exploration with Portugal, the country that inaugurated the European Age of Discovery. In 1492, two caravels and a carrack, commanded by Christopher Columbus, arrived in America, on an expedition that sought a westward oceanic passage across the Atlantic, to the Far East. This began the era of trans-oceanic trade routes, pioneered by the Spanish in the seas to the west of Europe and the Portuguese to the east.


title: Spanish Navy

text: Following the discovery of America and the settlement of certain Caribbean islands, such as Cuba, Spanish conquistadors Hernán Cortés and Francisco Pizarro were carried by the Spanish navy to the mainland, where they conquered Mexico and Peru respectively. The navy also carried explorers to the North American mainland, including Juan Ponce de León and Álvarez de Pineda, who discovered Florida (1519) and Texas (1521) respectively. In 1519, Spain sent out the first expedition of world circumnavigation in history, which was put in the charge of the Portuguese Commander Ferdinand Magellan. Following the death of Magellan in the Philippines, the expedition was completed under the command of Juan Sebastián Elcano in 1522. In 1565, a follow-on expedition by Miguel López de Legazpi was carried by the navy from New Spain (Mexico) to the Philippines via Guam to establish the Spanish East Indies, a base for trade with the Orient. For two and a half centuries, the Manila galleons operated across the Pacific linking Manila and Acapulco. Until the early 17th century, the Pacific Ocean was dominated by the Spanish Navy. Aside from the Marianas and Caroline Islands, several naval expeditions also discovered the Tuvalu archipelago, the Marquesas, the Solomon Islands and New Guinea in the South Pacific. In the quest for Terra Australis, Spanish explorers in the 17th century also discovered the Pitcairn and Vanuatu archipelagos. Most significantly, from 1565 Spanish fleets explored and colonised the Philippine archipelago, the Spanish East Indies.


title: Spanish Navy

text: After the unification of its kingdoms under the House of Habsburg, Spain maintained two largely separate fleets, one consisting chiefly of galleys for use in the Mediterranean and the other of sailing ships for the Atlantic, successors to the Aragonese and Castilian navies respectively. This arrangement continued until superseded by the decline of galley warfare during the 17th century. The completion of the Reconquista with the conquest of the Kingdom of Granada in 1492 had been followed by naval expansion in the Mediterranean, where Spain seized control of almost every significant port along the coast of North Africa west of Cyrenaica, notably Melilla (captured 1497), Mers El Kébir (1505), Oran (1509), Algiers (1510) and Tripoli (1510), which marked the furthest point of this advance. However, the hinterlands of these ports remained under the control of their Muslim and Berber inhabitants, and the expanding naval power of the Ottoman Empire brought about a major Islamic counter-offensive, which embroiled Spain in decades of intense warfare for control of the western Mediterranean. (Algiers and Tripoli would be lost to the Ottomans later in the 16th century.)


title: Spanish Navy

text: From the 1570s, the lengthy Dutch Revolt increasingly challenged Spanish sea power, producing powerful rebel naval forces that attacked Spanish shipping and in time made Spain's sea communications with its possessions in the Low Countries difficult. Most notable of these attacks was the Battle of Gibraltar in 1607, in which a Dutch squadron destroyed a fleet of galleons at anchor in the confines of the bay. This naval war took on a global dimension with actions in the Caribbean and the Far East, notably around the Philippines. Spain's response to its problems included the encouragement of privateers based in the Spanish Netherlands and known from their main base as Dunkirkers, who preyed on Dutch merchant ships and fishing trawlers.


title: Spanish Navy

text: At the Battle of Lepanto (1571), the Holy League, formed by Spain, Venice, the Papal States and other Christian allies, inflicted a great defeat on the Ottoman Navy, stopping Muslim forces from gaining uncontested control of the Mediterranean.


title: Spanish Navy

text: In the 1580s, the conflict in the Netherlands drew England into war with Spain, creating a further menace to Spanish shipping. The effort to neutralise this threat led to a disastrous attempt to invade England in 1588, however, the disaster of the English Armada the following year managed to return the balance between the belligerents. The defeat of 1588 led to a reform of fleet operations. The navy at this time was not a single operation but consisted of various fleets, made up mainly of armed merchantmen with escorts of royal ships. The Armada fiasco marked a turning point in naval warfare, where gunnery was now more important than ramming and boarding and so Spanish ships were equipped with purpose built naval guns. During the 1590s, the expansion of these fleets allowed a great increase in overseas trade and a massive increase in the importation of luxuries and silver. Nevertheless, inadequate port defences allowed an Anglo-Dutch force to raid Cadiz in 1596, and though unsuccessful in its objective of capturing the silver from the just returned convoy, was able to inflict great damage upon the city. Port defences at Cadiz were upgraded and all attempts to repeat the attack in the following centuries would fail.


title: Spanish Navy

text: Meanwhile, Spanish ships were able to step up operations in the English Channel, the North Sea and towards Ireland. They were able to capture many enemy ships, merchant and military, in the early decades of the 17th century and provide military supplies to Spanish armies in France and the Low Countries and to Irish rebels in Ireland.


title: Spanish Navy

text: By the middle of the 17th century, Spain had been drained by the vast strains of the Thirty Years' and related wars and began to slip into a slow decline. During the middle to late decades of the century, the Dutch, English and French were able to take advantage of Spain's shrinking, run-down and increasingly underequipped fleets. Military priorities in continental Europe meant that naval affairs were increasingly neglected. The Dutch took control of the smaller islands of the Caribbean, while England conquered Jamaica and France the western part of Santo Domingo. These territories became bases for raids on Spanish New World ports and shipping by pirates and privateers. The Spanish concentrated their efforts in keeping the most important islands, such as Cuba, Puerto Rico and the majority of Santo Domingo, while the system of treasure fleets, despite being greatly diminished, was rarely defeated in safely conveying its freight of silver and Asian luxuries across the Atlantic to Europe. Only two such convoys were ever lost to enemy action with their cargo, one to a Dutch fleet in 1628 and another to an English fleet in 1656. A third convoy was destroyed at anchor by another English attack in 1657, but it had already unloaded its treasure.


title: Spanish Navy

text: By the time of the wars of the Grand Alliance (1688–97) and the Spanish Succession (1702–14), the Habsburg regime had decided that it was more cost effective to rely on allied fleets, Anglo-Dutch and French respectively, than to invest in its own fleets.


title: Spanish Navy

text: The War of the Spanish Succession arose after the establishment on the Spanish throne of a House of Bourbon king, following the extinction of the Spanish Habsburg line. The internal division between supporters of a Habsburg and those of a Bourbon king led to a civil war and ultimately to the loss of Sicily, Sardinia, Menorca and Gibraltar. Gibraltar and Menorca were captured by Anglo-Dutch forces fighting under the Spanish flag of Habsburg contender Charles VI. Menorca was ultimately surrendered to Spain years later. At the end of the War of Spanish Succession, Spain's possessions in the Low countries and mainland Italy were ceded to Austria.


title: Spanish Navy

text: Attempting to reverse the losses of the previous war, in the War of the Quadruple Alliance (1718–20) the Spanish navy successfully convoyed armies to invade Sicily and Sardinia, but the poorly maintained escort fleet was destroyed by the British in the Battle of Cape Passaro and the Spanish invasion army was defeated in Italy by the Austrians. A major program to renovate and reorganise the run-down navy was begun. A "secretaría" (ministry) of the army and navy had been established by the Bourbon regime as early as 1714; which centralized the command and administration of the different fleets. Following the war of Quadruple Alliance, a program of rigorous standardization was introduced in ships, operations, and administration. Given the needs of its empire, Spanish warship designs tended to be more orientated towards long-range escort and patrol duties than for battle. A major reform of the Spanish navy was initiated, updating its ships and administration, which was helped by French and Italian experts, although Spaniards, most notably Antonio Castaneta, soon rose to prominence in this work, which made Spain a leader in warship design and quality again, as was demonstrated by ships like the Princesa. A major naval yard was established at Havana, enabling the navy to maintain a permanent force in the Americas for the defence of the colonies and the suppression of piracy and smuggling. In metropolitan Spain, significant forest reconnaissance operations were regularly undertaken by Spanish naval officers to seek out sources of timber suitable for shipbuilding.


title: Spanish Navy

text: During the War of the Polish Succession (1733–38), a renewed attempt to regain the lost Italian territories for the Bourbon dynasty was successful; with the French as allies and the British and Dutch neutral, Spain launched a campaign by sea and retook Sicily and southern Italy from Austria. In the War of Jenkins' Ear, the navy showed it was able to maintain communications with the American colonies and resupply Spanish forces in Italy in the face of British naval opposition. The navy played an important part in the decisive Battle of Cartagena de Indias in modern-day Colombia, where a massive British invasion fleet and army were defeated by a smaller Spanish force commanded by able strategist Blas de Lezo. This Spanish victory prolonged Spain's supremacy in the Americas until the early 19th century. The program of naval renovation was continued and by the 1750s the Spanish navy had outstripped the Dutch to become the third most powerful in the world, behind only those of Britain and France.


title: Spanish Navy

text: Joining France against Britain near the end of the Seven Years' War (1756–63), the navy failed to prevent the British capturing Havana, during which the Spanish squadron present was also captured. In the American War of Independence (1775–83), the Spanish navy was essential to the establishment, in combination with the French and Dutch navies, of a numerical advantage that stretched British naval resources. They played a vital role, along with the French and Dutch, in maintaining military supplies to the American rebels. The navy also played a key role in the Spanish army led operations that defeated the British in Florida. The bulk of the purely naval combat on the allied side fell to the French navy, although Spain achieved lucrative successes with the capture of two great British convoys meant for the resupply of British forces and loyalists in North America. Joint operations with France resulted in the capture of Menorca but failed in the siege of Gibraltar.


title: Spanish Navy

text: Having initially opposed France in the French Revolutionary Wars (1792–1802), Spain changed sides in 1796, but defeat by the British a few months later in the Battle of Cape St. Vincent (1797) and Trinidad (1798) was followed by the blockade of the main Spanish fleet in Cadiz. The run down of naval operations had as much to do with the confused political situation in Spain as it had to do with the blockade. The British blockade of Spain's ports was of limited success and an attempt to attack Cadiz was defeated; ships on special missions and convoys successfully evaded the Cadiz blockade and other ports continued to operate with little difficulty, but the main battle fleets were largely inactive. The blockade was lifted with the Peace of Amiens 1802. The war recommenced in 1804 and ended in 1808 when the Spain and the United Kingdom became allied against Napoleon. As in the first part, Cadiz was blockaded and Spanish naval activity was minimal. The most notable event was Spanish involvement in the Battle of Trafalgar under French leadership. This resulted in the Spanish navy losing eleven ships-of-the-line or over a quarter of its line-of-battle ships. After Spain became allied with the United Kingdom in 1808 in its war of independence, the Spanish navy joined the war effort against Napoleon.


title: Spanish Navy

text: The 1820s saw the loss of most of the Spanish Empire in the Americas. With the empire greatly reduced in size and Spain divided and unstable after its own war of independence, the navy lost its importance and shrank greatly.


title: Spanish Navy

text: However, in the 1850s and 1860s, particularly under the prime-ministership of General O'Donnell, significant investments were made in the Spanish naval squadrons of the Pacific. A new steam-powered naval squadron sailed around the Pacific escorting a Spanish scientific expedition and unfortunately became entangled in what has been billed the First War of the Pacific from 1864 to 1871. During the conflict, the Spanish massed a fleet of 15 vessels to combat the combined navies of Peru, Chile, and Ecuador.


title: Spanish Navy

text: The 1890s saw the Spanish Navy gain several armored cruisers—important for maintaining connection with the Spanish Empire's remaining colonies—including the "Emperador Carlos V". As of 1896, according to the plans of Admiral José María Beránger, there were three naval divisions based at Cadiz, Ferrol, and Cartagena. Each division was composed of ironclads, in addition to auxiliary squadrons for defense of the Spanish coastline. That year the Armada consisted of one battleship, eight cruisers of the first class, six of the second class, and nine of the third class, as well as 38 torpedo craft. There were an additional ten vessels under construction. As of 1896 there were 1,002 officers in the navy, along with 725 mechanics, 14,000 sailors, and 9,000 marines. Their numbers were maintained by conscription of the seafaring population.


title: Spanish Navy

text: During the Spanish–American War in 1898, a badly supported and equipped Spanish fleet of four armored cruisers and two destroyers was overwhelmed by numerically and technically superior forces (three new battleships, one new second class battleship, and one large armored cruiser) as it tried to break out of an American blockade in the Battle of Santiago de Cuba. Admiral Cervera's squadron was overrun in an attempt to break a powerful American blockade off Cuba. In the Philippines, a squadron, made up of aging ships, including some obsolete cruisers, had already been sacrificed in a token gesture in Manila Bay. The Battle of Manila Bay took place on 1 May 1898, during the Spanish–American War. The American Asiatic Squadron under Commodore George Dewey engaged and destroyed the Spanish Pacific Squadron under Admiral Patricio Montojo y Pasarón. The engagement took place in Manila Bay in the Philippines, and was the first major engagement of the Spanish–American War. This war marked the end for the Spanish Navy as a global maritime force.


title: Spanish Navy

text: At the end of the 19th century, the Spanish Navy adopted the "Salve Marinera", a hymn to the Virgin Mary as Stella Maris, as its official anthem.


title: Spanish Navy

text: During the Rif War in Morocco, the Spanish navy conducted operations along the coast, including the Alhucemas landing in 1925, the first air-naval landing of the world. At that time, the Navy developed a Naval Aviation branch, the "Aeronáutica naval".


title: Spanish Navy

text: In 1931, following the proclamation of the Second Spanish Republic, the Navy of the Spanish Kingdom became the Spanish Republican Navy. Admiral Aznar's casual comment: ""Do you think it was a little thing what happened yesterday, that Spain went to bed as a monarchy and rose as a republic"" became instantly famous, going quickly around Madrid and around Spain, making people accept the fact and setting a more relaxed mood. The Spanish Republican Navy introduced a few changes in the flags and ensigns, as well as in the navy officer rank insignia. The executive curl "(La coca)" was replaced by a golden five-pointed star and the royal crown of the brass buttons and of the officers' breastplates "(La gola)" became a mural crown.


title: Spanish Navy

text: The Spanish Republican Navy became divided after the coup of July 1936 that led to the Spanish Civil War (1936–39). The fleet's two small dreadnoughts, one heavy cruiser, one large destroyer and half a dozen submarines and auxiliary vessels were lost in the course of the conflict.


title: Spanish Navy

text: Like the rest of the Spanish armed forces, the Spanish Navy maintained Franco's policy of neutrality during World War II.


title: Spanish Navy

text: Since the mid-20th century, the Spanish Navy began a process of reorganization to once again become one of the major navies of the world. After the development of the s based on the US Navy's , the Spanish Navy embraced the American naval doctrine. Spain became a member of NATO in 1982 and the Armada Española has taken part in many coalition peacekeeping operations, from SFOR to Haiti and other locations around the world. Today's Armada is a modern navy with a carrier group, a modern strategic amphibious ship (which replaced a dedicated aircraft carrier in 2011), modern frigates (F-100 class) with the Aegis Combat System, F-80-class frigates, minesweepers, new s, amphibious ships and various other ships, including oceanographic research ships.


title: Spanish Navy

text: The Armada's special operations and unconventional warfare capability is embodied in the Naval Special Warfare Command (Mando de Guerra Naval Especial), which is under the direct control of the Admiral of the Fleet. The unit in charge of special operations is the "Naval Special Warfare Force" (Fuerza de Guerra Naval Especial), which is a merge of the previous "Special Operations Unit" (Unidad de Operaciones Especiales (UOE)) and the "Special" "Combat Diver Unit" (Unidad Especial de Buceadores de Combate (UEBC)). This unit is trained in maritime counter-terrorism, specialized combat diving and swimming, coastal infiltration, ship boarding, direct action, special reconnaissance, hydrographic reconnaissance and underwater demolitions.


title: Spanish Navy

text: Armada officers receive their education at the Spanish Naval Academy (ENM). They are recruited through two different methods:


title: Spanish Navy

text: Subordinate to the Spanish Chief of Naval Staff, stationed in Madrid, are four area commands: the Cantabrian Maritime Zone with its headquarters at Ferrol on the Atlantic coast; the Straits Maritime Zone with its headquarters at San Fernando near Cadiz; the Mediterranean Maritime Zone with its headquarters at Cartagena; and the Canary Islands Maritime Zone with its headquarters at Las Palmas de Gran Canaria. Operational naval units are classified by mission and assigned to either the combat forces, the protective forces, or the auxiliary forces. Combat forces are given the tasks of conducting offensive and defensive operations against potential enemies and for assuring maritime communications. Their principal vessels include a carrier group, naval aircraft, transports, landing vessels, submarines, and missile-armed fast attack craft. Protective forces have the mission of securing maritime communications over both ocean and coastal routes, securing the approaches to ports and maritime terminals. Their principal components are frigates, corvettes, and minesweepers. It also has marine units for the defense of naval installations. Auxiliary forces are responsible for transportation and provisioning at sea and has diverse tasks like coast guard operations, scientific work, and maintenance of training vessels. In addition to supply ships and tankers, the force included destroyers and a large number of patrol craft.


title: Spanish Navy

text: Until February 2013, when it was decommissioned because of budget cuts, the second largest vessel of the "Armada" was the aircraft carrier "Principe de Asturias", which entered service in 1988 after completing sea trials. Built in Spain, it was designed with a "ski-jump" takeoff deck. Its complement was 29 AV-8 Harrier II vertical (or short) takeoff and landing (V/STOL) aircraft or 16 helicopters designed for antisubmarine warfare and to support marine landings.