Persius/hicric huggingface dataset:
Sciatica overview

# Overview
Sciatica is pain caused by general compression and/or irritation of one of five nerve roots that are branches of the sciatic nerve.  The pain is felt in the lower back, buttock, and/or various parts of the leg and foot. In addition to pain, which is sometimes severe, there may be numbness, muscular weakness, and difficulty in moving or controlling the leg. Typically, the symptoms are only felt on one side of the body.
Although sciatica is a relatively common form of low back pain and leg pain, the true meaning of the term often is misunderstood. Sciatica is a set of symptoms rather than a diagnosis for what is irritating the root of the nerve, causing the pain. This point is important, because treatment for sciatica or sciatic symptoms often will be different, depending upon the underlying cause of the symptoms.
The first cited use of the word "sciatica" was registered in 1450.
Scimitar syndrome
Synonyms and related keywords: Venolobar syndrome, hypogenetic lung syndrome.

# Overview
Scimitar syndrome (a variant of Partially Anomalous Pulmonary Venous Return or PAPVR) is a rare congenital heart defect is characterized by a hypoplastic lung that is drained by an anomalous vein into the systemic venous system. It is essentially a combination of pulmonary hypoplasia and partial anomalous pulmonary venous return. It almost exclusively occurs on the right side. The hemodynamics are that of an acyanotic left to right shunt. The anomalous vein most commonly drains into the IVC, right atrium or portal vein. The lung is frequently perfused by the aorta, but the bronchial tree is still connected and thus the lung is not sequestered. CXR findings are that of a small lung with ipsilateral mediastinal shift, and in one third of cases the anomalous draining vein may be seen as a tubular structure paralleling the right heart border in the shape of a Turkish sword (scimitar). Scimitar syndrome is associated with congenital heart disease, ipsilateral diaphragmatic anomalies and vertebral anomalies.

# Presentation
The anomalous venous return forms a curved shadow on chest x-ray such that it resembles a scimitar. This is called the Scimitar Sign. Associated abnormalities include right lung hypoplasia with associated dextrocardia, pulmonary artery hypoplasia and pulmonary arterial sequestration.

# Diagnosis
The diagnosis is made by transthoracic or transesophageal echocardiography, angiography, and more recently by CT angiography or MR Angiography.
- Chest x-ray: Scimitar Syndrome (Image courtesy of Dr Donna D'Souza)

# Treatment
Surgical correction should be considered in the presence of significant left to right shunting (Qp:Qs  2:1) and pulmonary hypertension.  This involves creation of an inter-atrial baffle to redirect the pulmonary venous return into the left atrium. Alternatively, the anomalous vein can be re-implanted directly into the left atrium.
Selectable marker

# Overview
An alternative to a selectable marker is a screenable marker, which allows the researcher to distinguish between wanted and unwanted cells.
Examples of selectable markers include:
- the Abicr gene 
- Neo gene from Tn5, which confers antibiotic resistance to geneticin
A selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture, that confers a trait suitable for artificial selection. They are a type of reporter gene used in laboratory microbiology, molecular biology, and genetic engineering to indicate the success of a transfection or other procedure meant to introduce foreign DNA into a cell. Selectable markers are often antibiotic resistance genes; bacteria that have been subjected to a procedure to introduce foreign DNA are grown on a medium containing an antibiotic, and those bacterial colonies that can grow have successfully taken up and expressed the introduced genetic material.
Self-condensation
Self-condensation is an organic reaction in which a chemical compound containing a carbonyl group acts both as the electrophile and the nucleophile in an aldol condensation. It is also called a  symmetrical aldol condensation as opposed to a mixed aldol condensation in which the electrophile and nucleophile are different species.
For example, two molecules of acetone condense to a single compound mesityl oxide in the presence of an ion exchange resin:
For synthetic uses, this is generally an undesirable, but spontaneous and favored side-reaction of mixed aldol condensation, and special precautions are needed to prevent it.
Self report study
A self report study is a research method employed by sociologists and criminologists to determine the extent of crime and deviance.
Most self report studies involve confidential questionnaires that invite the respondents to record voluntarily whether or not they have committed any of the offences listed.The data can then be compared with official conviction rates to discover which types of offenders are most likely to be convicted.
Self report studies have revealed that criminal acts are spread throughout the population, and that the official difference between male and female, or working and middle class rates of criminality are far smaller than the official statistics would suggest.
In general, self-report studies identify more offenders than the official crime statistics and different types of offender. These research methods have thus brought into question many of the conventional explanations of crime which have been based on official police records.

# Some problems of self report studies
- Unreliable answers
Respondents may exaggerate
Respondents may be embarrassed
Forgetfulness
- Respondents may exaggerate
- Respondents may be embarrassed
- Forgetfulness
- A biased selection of offences
May uncover trivial offences, but not serious, uncommon ones
Only a limited menu of offences are listed
May ignore middle class crime
- May uncover trivial offences, but not serious, uncommon ones
- Only a limited menu of offences are listed
- May ignore middle class crime
- A biased selection of interviewees
Researchers may not be able to gain access to certain categories of offender. Many self-report studies have involved a 'captive audience' of school age students or prisoners.
Non respondents may distort data (e.g. truants in school)
On the other hand the rich and powerful, such as business executives, may exclude researchers looking at issues such as corporate crime and fraud.
- Researchers may not be able to gain access to certain categories of offender. Many self-report studies have involved a 'captive audience' of school age students or prisoners.
- Non respondents may distort data (e.g. truants in school)
- On the other hand the rich and powerful, such as business executives, may exclude researchers looking at issues such as corporate crime and fraud.

# Further reading
Moore, Stephen (1996) Investigating Deviance,  Second Edition, Sociology in Action Series, Collins, pp 224-228
Semantic dementia

# Overview
Semantic dementia (SD) is a progressive neurodegenerative disorder characterized by loss of semantic memory in both the verbal and non-verbal domains. The most common presenting symptoms are in the verbal domain however (with loss of word meaning) and it is therefore often characterized (incorrectly) as a primary language disorder (a so-called progressive fluent aphasia).
SD is one of the three canonical clinical syndromes associated with frontotemporal lobar degeneration.  SD is a clinically-defined syndrome, but is associated with predominantly temporal lobe atrophy (left greater than right) and hence is sometimes called temporal variant FTLD (tvFTLD).
It was first described by Professor Elizabeth Warrington in 1975 (Warrington EK. The selective impairment of semantic memory. Q J Exp Psychol. 1975 Nov;27(4):635-57) but was not given the name semantic dementia until 1989 (Snowden JS, Goulding PJ, Neary D. Semantic dementia: a form of circumscribed cerebral atrophy. Behav Neurol 1989;2:167-182.).

# Signs and Symptoms
SD patients often present with the complaint of word-finding difficulties. On further questioning, patients often appear to have lost the meaning of certain words (e.g. asking "What is a fish?"). As the disease progresses, behavioural and personality changes are often seen similar to those seen in frontotemporal dementia although cases have been described of 'pure' semantic dementia with few late behavioural symptoms.

# Neuropsychology
Patients perform poorly on tests of semantic knowledge. Published tests include both verbal and non-verbal tasks e.g.
The Warrington concrete and abstract word synonym test (Warrington EK, McKenna P, Orpwood L. Single word comprehension: a concrete and abstract word synonym test. Neuropsychological Rehabilitation 1998; 8: 143-154.) and The Pyramids and Palm Trees task (Howard and Patterson, 1992)
Testing will also reveal deficits in picture naming (with semantic errors being made e.g. "dog" for a picture of a hippopotamus) and decreased category fluency.

# Imaging
Structural MRI imaging shows a characteristic pattern of atrophy in the temporal lobes (predominantly on the left) with inferior greater than superior involvement and anterior temporal lobe atrophy greater than posterior. This distinguishes it from Alzheimer's disease (Chan et al. Patterns of temporal lobe atrophy in semantic dementia and Alzheimer's disease. Ann Neurol. 2001 Apr;49(4):433-42).

# Pathology
The majority of patients with SD will have ubiquitin-positive, tau-negative inclusions although like all of the FTLD syndromes other pathologies have been described including Pick's disease and other tau positive pathology (Davies RR et al. The pathological basis of semantic dementia.
Brain. 2005 Sep;128(Pt 9):1984-95.)

# Genetics
Of all the FTLD syndromes SD is least likely to run in families and is usually sporadic (Goldman JS et al. Comparison of family histories in FTLD subtypes and related tauopathies. Neurology. 2005 Dec 13;65(11):1817-9.)

# Management
There is currently no known curative treatment for this condition. Supportive care is essential in what is a greatly debilitating problem.
Senna obtusifolia
Senna obtusifolia (syn. Cassia obtusifolia L., Cassia tora, Emelista tora) is a plant in the genus Senna.  It is also known as foetid cassia, sickle senna, Chinese senna, sicklepod, sickle-pod, sickle pod, coffee weed, coffeeweed, coffee pod, coffee-pod, java bean, java-bean, or arsenic weed. It grows wild in North, Central, and South America, Asia, Africa, and Oceania, and is considered a particularly serious weed in many places.
The species's name comes from the Latin obtus ("dull or blunt"), and folium ("leaf"). Its leaves, seeds, and root are used medicinally, primarily in Asia. It is believed to possess a laxative effect, as well as to be beneficial for the eyes.
The plant's seeds are a source of cassia gum, a food additive usually used as a thickener.  As a folk remedy, the seeds are often roasted, then boiled in water to produce a tea.  Roasted and ground, the seeds have also been used as a substitute for coffee.
- Senna obtusifolia
Senna obtusifolia
- Leaves
Leaves
- Stem
Stem

# Other names
- Chinese: pinyin: jue ming zi (traditional: ; simplified: )
- Japanese: ebisu-gusa, 
- Korean: gyeolmyeongja (hangul: ; hanja: )
- Portuguese:fedegoso
- Turkish:sinameki
Shallow breathing

# Overview
Shallow breathing is the drawing of minimal breath into the lungs, usually by drawing air into the chest area using the intercostal muscles rather than throughout the lungs via the diaphragm. Shallow breathing can result in or be symptomatic of rapid breathing and hyperventilation. Most people who breath shallowly do it throughout the day and are almost always unaware of the condition.
Shallow breathing is considered unhealthy, the better alternative being diaphragmatic breathing.

# Differential diagnosis of underlying causes
Several conditions are marked by or symptomatic of shallow breathing. The more common of these symptoms include: various anxiety disorders, asthma, hyperventilation, pneumonia, pulmonary edema, and shock. Anxiety, stress, and panic attacks often accompany shallow breathing.
Shapiro-Wilk test

# Overview
In statistics, the Shapiro-Wilk test tests the null hypothesis that a sample x1, ..., xn came from a normally distributed population. It was published in 1965 by Samuel Shapiro and Martin Wilk.
The test statistic is
where
- x(i) (with parentheses enclosing the subscript index i) is the ith order statistic, i.e., the ith-smallest number in the sample;
- \overline{x}=(x_1+\cdots+x_n)/n\, is the sample mean;
- the constants ai are given by
The user may reject the null hypothesis if W is too small.
Shoulder dystocia

# Overview
Shoulder dystocia is a specific case of dystocia whereby the anterior shoulder of the infant cannot pass below the pubic symphysis, or requires significant manipulation to pass below, the pubic symphysis. It is diagnosed when the shoulders fail to deliver shortly after the fetal head.
A number of obstetrical maneuvers are used to facilitate delivery at this point, including McRobert's maneuver; suprapubic pressure (or Rubin I); Rubin II or posterior pressure on the anterior shoulder; Woods' screw maneuver which leads to turning the anterior shoulder to the posterior and vice versa; and Jacquemier's maneuver (also called Barnum's maneuver), or delivery of the posterior shoulder. More drastic maneuvers include Zavanelli's maneuver or internal cephalic replacement followed by Cesarean section; intentional clavicular fracture, symphisiotomy, and abdominal rescue, described by O'Shaughnessy, where a hysterotomy facilitates vaginal delivery of the impacted shoulder.
Although the definition is imprecise, it occurs in approximately 1% of vaginal births. There are well-recognised risk factors, such as diabetes, fetal macrosomia, and maternal obesity, but it is often difficult to predict. Despite appropriate obstetric management, fetal injury (such as brachial plexus injury) or even fetal death can be a complication of this obstetric emergency.
Sickle cell trait

# Overview
Sickle cell trait describes the way a person can inherit some of the genes of sickle cell disease, but not develop symptoms. Sickle cell disease is a blood disorder in which the body produces an abnormal type of the oxygen-carrying substance hemoglobin in the red blood cells.
Normal hemoglobin is called hemoglobin A, but people with sickle cell disease have only hemoglobin S, which turns normal, round red blood cells into abnormally curved (sickle) shapes.
Normally, a person inherits two genes (one from each parent) that produce beta-globin, a protein needed to produce normal hemoglobin (hemoglobin A). A person with sickle cell trait inherits one normal beta-globin gene (hemoglobin A) and one defective gene (hemoglobin S).
People with sickle cell trait rarely have symptoms due to the condition because they also have some normal hemoglobin. However, they can pass the sickle cell trait to their children, and in rare cases, exercise-induced dehydration or exhaustion can cause healthy red blood cells to turn sickle-shaped, which can cause death.
A person in whom both beta-globin genes are abnormal (they produce hemoglobin S) has sickle cell disease, which can cause serious problems. Both parents must have either the sickle cell trait or the disease itself for a child to have sickle cell disease.
People who have the sickle cell trait have reduced susceptibility to malaria, due to natural selection for the heterozygote advantage. However, people with the sickle cell trait can still contract severe cases of malaria.
Signal processing
Signal processing is the analysis, interpretation, and manipulation of signals.  Signals of interest include sound, images, biological signals such as ECG, radar signals, and many others. Processing of such signals includes filtering, storage and reconstruction, separation of information from noise (for example, aircraft identification by radar), compression (for example, image compression), and feature extraction (for example, speech-to-text conversion).
In communication systems, signal processing only occurs at OSI layer 1, the physical layer (modulation, equalization, multiplexing, radio transmission, etc) in the seven layer OSI model, as well as at OSI layer 6, the presentation layer (source coding, including analog-to-digital conversion and data compression).

# Signal classification
Signals are electrical representations of time-varying or spatial-varying physical quantities, either analog or digital, and may come from various sources. In the context of signal processing, arbitrary binary data streams are not considered as signals, but only digital signals that are representations of analog physical quantities.
For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve digital filtering and compression of digital signals.
- Analog signal processingfor signals that have not been digitized, as in classical radio, telephone, radar, and television systems
- Digital signal processingfor signals that have been digitized.  Processing is done by digital circuits such as ASICs, FPGAs, general-purpose microprocessors or computers, or specialized digital signal processor chips.
- Statistical signal processinganalyzing and extracting information from signals based on their statistical properties
- Audio signal processingfor electrical signals representing sound, such as music
- Speech signal processingfor processing and interpreting spoken words
- Image processingin digital cameras, computers, and various imaging systems
- Video processingfor interpreting moving pictures
- Array processingfor processing signals from arrays of sensors
Simmonds' disease
Simmonds' disease (also Simmonds' syndrome) refers to panhypopituitarism caused by the destruction of the pituitary gland due to infiltrative processes (e.g. lymphocytic), tumours (pituitary adenomas or craniopharyngiomas) or trauma (cranial injury or following surgery).
Sheehan's syndrome is a sub-classification of Simmond's disease occurring specifically in the peripartum period.

# Eponym
It was first described by Morris Simmonds when a patient presented with 'fatal cachexia', although his patient went on to live for 11 more years. 

# Symptoms
Although cachexia may be present, the disease is characterised by symptoms due to decreased gonadal, thyroidal and adrenal function. These include:
- amenorrhoea or oligomenorrhoea, impotence, loss of libido
- tiredness, hypotension
- waxy skin, loss of body hair
See Hypopituitarism
Sine wave pattern
Synonyms and keywords: Sinusoidal pattern

# Overview
The sine wave pattern is one of the manifestations of severe hyperkalemia. The sine wave pattern depicts worsening cardiac conduction delay caused by the elevated level of extracellular potassium. The morphology of this sinusoidal pattern on ECG results from the fusion of wide QRS complexes with T waves.

# Pathophysiology
- Hyperkalemia induces electrophysiological changes in the myocardium leading to a series of findings on ECG. One of these ECG changes is a sine wave pattern which is a manifestation of severe hyperkalemia.
- Different levels of hyperkalemia cause different electrophysiological changes, the first sign of which is inverted T waves that are the result of accentuation of repolarization.
- Further increase in the potassium level causes a decrease in the velocity of cardiac conduction leading to PR interval prolongation, QRS widening, decrease in the amplitude of P waves and eventually absence of P waves. It is important to note that the absence of P waves does not depict sinus arrest at this level; in fact, the SA node continues to function without causing atrial contraction but rather causing only ventricular contraction. This rhythm is referred to as sinoventricular rythm.
- As the potassium level further increases, the delay in cardiac conduction worsens leading to further widening of the QRS complex which ends up in the fusion of the QRS complex with the T wave. The fusion of the QRS complex with the T wave in the absence of P wave is referred to as the sine wave pattern.

# Differential Diagnosis
- Ventricular tachycardia
- SVT with bundle branch block

# ECG Examples
Shown below is an ECG demonstrating the sine wave pattern.
Copyleft image obtained courtesy of ECGpedia, :DVA0578.jpg
Sinus transversus
The transverse sinuses (left and right lateral sinuses), within a human head, are two areas beneath the brain, which allow blood veins to span the area, from the back of the head towards the nose. They drain from the straight sinus and superior sagittal sinus (along the top and back of the brain) to the sigmoid sinuses (at the center of the head), at the internal jugular vein.  See diagram (at right): labeled under the brain as "SIN. TRANS." (for Latin: sinus transversus).
The transverse sinuses are of large size and begin at the internal occipital protuberance; one, generally the right, being the direct continuation of the superior sagittal sinus, the other of the straight sinus.
Each transverse sinus passes lateralward and forward, describing a slight curve with its convexity upward, to the base of the petrous portion of the temporal bone, and lies, in this part of its course, in the attached margin of the tentorium cerebelli; it then leaves the tentorium and curves downward and medialward to reach the jugular foramen, where it ends in the internal jugular vein.
In its course it rests upon the squama of the occipital, the mastoid angle of the parietal, the mastoid part of the temporal, and, just before its termination, the jugular process of the occipital; the portion which occupies the groove on the mastoid part of the temporal is sometimes termed the sigmoid sinus.
The transverse sinuses are frequently of unequal size, with the one formed by the superior sagittal sinus being the larger; they increase in size as they proceed, from back to center.
On transverse section, the horizontal portion exhibits a prismatic form, the curved portion has a semicylindrical form.
They receive the blood from the superior petrosal sinuses at the base of the petrous portion of the temporal bone; they communicate with the veins of the pericranium by means of the mastoid and condyloid emissary veins; and they receive some of the inferior cerebral and inferior cerebellar veins, and some veins from the diploe.
The petrosquamous sinus, when present, runs backward along the junction of the squama and petrous portion of the temporal, and opens into the transverse sinus.

# Additional images
- Left parietal bone. Inner surface.
- Dura mater and its processes exposed by removing part of the right half of the skull, and the brain.
- The sinuses at the base of the skull.
- Horizontal section through left ear; upper half of section.
- Drawing to illustrate the relations of the brain to the skull.
- Relations of the brain and middle meningeal artery to the surface of the skull.
- Left temporal bone showing surface markings for the tympanic antrum (red), transverse sinus (blue), and facial nerve (yellow).