title: Huo Yuanjia

text: In 1902, Huo responded to a challenge advertised by a Russian wrestler in Xiyuan Park, Tianjin. The wrestler openly called the Chinese "sick men of Asia" because no one accepted his challenge to a fight. The Russian forfeited when Huo accepted his challenge and told Huo that he was merely putting on a performance to make a living and apologised for his earlier remark in the newspaper.


title: Huo Yuanjia

text: Between 1909 and 1910, Huo travelled to Shanghai twice to accept an open challenge posed by an Irish boxer, Hercules O'Brien. The two of them had arguments over the rules governing such boxing matches and eventually agreed that whoever knocked down his opponent would be the victor. O'Brien supposedly fought Huo and lost. Huo's victory was a great inspiration to the Chinese people and had them questioning the basis of imperialistic dominance. However, there is a lot of controversy over whether the fight ever took place. A recent article states that O'Brien opted to leave town instead.


title: Huo Yuanjia

text: Between 1909 and 1910, Huo founded the Chin Woo Physical Training Centre (精武体操会) (later renamed to "Chin Woo Athletic Association") with his close friend Nong Jinsun, who served as the president of the association. Huo was encouraged by his close friends and was sponsored by Sun Yat-sen and Song Jiaoren, who were living in Tokyo. The centre was meant to be a school for learning the arts of self-defense and improvement of health and mind.


title: Huo Yuanjia

text: Huo suffered from jaundice and tuberculosis and started seeing a Japanese physician for medication and treatment. The physician, who was a member of the Japanese Judo Association in Shanghai, invited Huo to a competition upon hearing of the latter's fame. Huo's student, Liu Zhensheng, competed with a judo practitioner. Although there were disputes over who won the match, both sides generally agreed that the disagreement culminated in a brawl and that members of the judo team, including the head instructor, were injured, some with broken fingers and hands.


title: Huo Yuanjia

text: Huo died in 1910 at the age of 42. He was survived by his wife Ms. Wang (王氏; given name unknown) (1869?–1960), two sons Huo Dongzhang (霍東章) and Huo Dongge (霍東閣), and three daughters Huo Dongru (霍東茹), Huo Dongling (霍東玲) and Huo Dongqin (霍東琴).


title: Huo Yuanjia

text: The historian Chen Gongzhe, who was also one of Huo's students, believed that the cause of his master's death was hemoptysis. Chen wrote that Huo was introduced to a Japanese physician by the judo instructor as his health declined. The physician prescribed some medicine for his condition, but Huo's health continued to deteriorate. Huo was admitted to the Shanghai Red Cross Hospital, where he died two weeks later. Although Chen did not mention that the medicine prescribed by the Japanese physician contained arsenic or any other poison, some leaders of the Chin Woo Athletic Association speculated that Huo was poisoned around the time of his death.


title: Huo Yuanjia

text: In 1989, Huo's and his wife's graves were excavated and their remains were relocated elsewhere. Black spots were discovered in Huo's pelvic bones. The Tianjin Municipality Police Laboratory confirmed that they contained arsenic. However, it is difficult to ascertain whether Huo's death was caused by malicious poisoning or by the prescription of medicine. This was because arsenic trioxide has been used therapeutically for approximately 2,400 years as part of traditional Chinese medicine.


title: Huo Yuanjia

text: Huo died months after co-founding the Chin Woo Athletic Association. Before his death, he invited Zhao Lianhe of the Shaolin Mizong Style to teach in Chin Woo and Zhao agreed. Subsequently, a number of other martial arts masters agreed to teach at the school. They included Eagle Claw master Chen Zizheng, Seven Star Praying Mantis master Luo Guangyu, Xingyiquan master Geng Xiaguang, and Wu Jianquan, the founder of Wu-style taijiquan. In June 1910, the "Eastern Times" announced the establishment of the Chin Woo association in Huo's name. It was the first civil martial arts organisation in China that was not associated with a particular school or style.


title: Huo Yuanjia

text: Huo's life has been adapted into films and television series. In these adaptations, Huo is typically depicted as a heroic martial artist who fights to uphold the dignity of the Chinese people in the face of foreign aggression. He is secretly poisoned to death by foreigners, usually the Japanese, who see him as a threat to their exploitation of China. A notable feature in some of these adaptations is the appearance of Chen Zhen, a fictional character first portrayed by Bruce Lee in the 1972 film "Fist of Fury" (released in the U.S. as "The Chinese Connection"). In the film, Chen Zhen is one of Huo's apprentices. He brings his teacher's murderers to justice and ensures that Huo's legacy, the Jingwu School and "Jingwu Spirit", continues to live on. Notable actors who have portrayed Huo on screen include Wong Yuen-sun in "The Legendary Fok" (1981), Bryan Leung in "Legend of a Fighter" (1982), Eddy Ko in "Fist of Fury" (1995), Vincent Zhao in "Huo Yuanjia" (2001), Jet Li in "Fearless" (2006), and Ekin Cheng in "Huo Yuanjia" (2008).


title: Kaanekkaane

text: Kaanekkaane is a 2021 Indian Malayalam-language drama thriller film written by Bobby and Sanjay and directed by Manu Ashokan. The film stars Suraj Venjaramoodu, Tovino Thomas, Aishwarya Lekshmi and Shruthi Ramachandran in important roles. The film which was produced by T. R. Shamsudheen under the banner of DreamKatcher, made a direct release through SonyLIV on 17 September 2021.


title: Kaanekkaane

text: Deputy Tahsildar Paul mathai arrives in town for some court dealings, he visits his late daughter's home to meet his long-seen grandson. Allen, her husband is now married to sneha and leading a seemingly happy life which irks Paul out of jealousy, mostly against the new woman for taking his daughter's role as mother. Even though Paul decides to accept the situation, he is suddenly taken aback by an abrupt revelation about the death of his daughter which prompts him to seek justice through any means available. An emotional transverse through vulnerable human conditions .


title: Kaanekkaane

text: The film was announced by the director through the social media on 26 September 2020. The film marks the second directional of Manu Ashokan after the film "Uyare" and is the second movie in which Aishwarya Lekshmi and Tovino Thomas reunites after the film "Mayanadi". The shooting of the film began in Ernakulam on 18 October 2020 after the Pooja Ceremony. Tovino Thomas who was undergoing rest after getting injured during the shoot of the movie Kala, joined the set during the first week of November. After a single schedule of about one and half months, the shooting was completed during the start of December 2020. The dubbing and other post production works of the movie was completed by the end of January 2021. The first look poster of the film was launched on January 21, 2021, by Mammotty, Manju Warrier, Indrajith Sukumaran, Asif Ali and other few actors, on Tovino's birthday. The teaser of the film was released on September 11, 2021. The trailer of the film was released on September 12, 2021


title: Kaanekkaane

text: Alby Antony has been roped in as the cinematographer and Abhilash Balachandran is the editor of the movie. Dileep Nath does the art work in the movie. Sreya Aravind is the costume designer and makeup of the film is handled by Jayan Poonkunnam.


title: Kaanekkaane

text: Ranjin Raj is the music director of the movie. He has composed the song and did the background scores of the movie. The film has a single song titled "Palnilavin Poykayil". The veteran singer G. Venugopal sings the male version of the song and Sithara Krishnakumar sings its female version


title: Kaanekkaane

text: The film was not released in theatre due to the COVID-19 pandemic and was directly released on the OTT Platform, SonyLIV on September 17, 2021. It was the first Malayalam movie to be premiered through SonyLIV.


title: Kaanekkaane

text: The movie opened to generally positive reviews from critics and audiences alike. "The Times Of India" gave a rating of 3.5 on 5 for the movie and commented that, "Kaanekkane is an emotional ride throughout, exploring the scenario from the point-of-view of each of the imperfect characters involved, through its non-linear narration." S. R. Praveen of "The Hindu" wrote that, "The ‘Uyare’ director's latest film works when it patiently unravels its many layers, but spoils it with a convenient stitching-up towards the end". Sawmya Rajendran of "The News Minute" said that, "Kaanekkaane is certainly among the better thrillers to have come out of Malayalam cinema in recent times. Within its runtime of just over two hours, Kaanekkaane keeps us on the edge, for the most part, unable to choose which of the characters should triumph." "Indian Express" gave a rating of 3 on 5 for the film and wrote that, "All actors delivered strong performance, Suraj's performance as Paul Mathai was outstanding in the film, which explores how difficult it is to look someone you love in the eye and tell them you have wronged them.


title: Kaanekkaane

text: "International Business Times" wrote that, "Kaanekkaane is not a classic but a great film that is worth a watch. Manu Ashokan has succeeded in portraying human emotions with perfection on screen, and we can expect more from this director in the future and Bobby-Sanjay's script was brilliant, and the writers have sketched each and every character in a perfect manner." "Pinkvilla" rated 3 on 5 for the movie and said that, "The movie engages with its clear, coherent character work, its self-contained moral takeaways and amazing performances and it sheds some light on the darkest pitfalls of human nature that has not been delved with much finesse that sure sheds some light on the dark edges of our souls that stay hidden under the seemingly perfect outside." The "Firstpost" gave a rating of 3.5 on 5 for the movie and said that, "Kaanekkaane is at one level a thriller, but an unconventional addition to that genre since the big reveal comes much before the climax and the heart and soul of Kaanekkaane is Suraj Venjaramoodu who has had an incredible journey in recent years from character artiste to leading man."


title: Error correction code

text: In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for controlling errors in data over unreliable or noisy communication channels. The central idea is the sender encodes the message with redundant information in the form of an ECC. The redundancy allows the receiver to detect a limited number of errors that may occur anywhere in the message, and often to correct these errors without retransmission. The American mathematician Richard Hamming pioneered this field in the 1940s and invented the first error-correcting code in 1950: the Hamming (7,4) code.


title: Error correction code

text: ECC contrasts with error detection in that errors that are encountered can be corrected, not simply detected. The advantage is that a system using ECC does not require a reverse channel to request retransmission of data when an error occurs. The downside is that there is a fixed overhead that is added to the message, thereby requiring a higher forward-channel bandwidth. ECC is therefore applied in situations where retransmissions are costly or impossible, such as one-way communication links and when transmitting to multiple receivers in multicast. Long-latency connections also benefit; in the case of a satellite orbiting around Uranus, retransmission due to errors can create a delay of five hours. ECC information is usually added to mass storage devices to enable recovery of corrupted data, is widely used in modems, and is used on systems where the primary memory is ECC memory.


title: Error correction code

text: ECC processing in a receiver may be applied to a digital bitstream or in the demodulation of a digitally modulated carrier. For the latter, ECC is an integral part of the initial analog-to-digital conversion in the receiver. The Viterbi decoder implements a soft-decision algorithm to demodulate digital data from an analog signal corrupted by noise. Many ECC encoders/decoders can also generate a bit-error rate (BER) signal, which can be used as feedback to fine-tune the analog receiving electronics.


title: Error correction code

text: The maximum fractions of errors or of missing bits that can be corrected are determined by the design of the ECC code, so different error correcting codes are suitable for different conditions. In general, a stronger code induces more redundancy that needs to be transmitted using the available bandwidth, which reduces the effective bit-rate while improving the received effective signal-to-noise ratio. The noisy-channel coding theorem of Claude Shannon can be used to compute the maximum achievable communication bandwidth for a given maximum acceptable error probability. This establishes bounds on the theoretical maximum information transfer rate of a channel with some given base noise level. However, the proof is not constructive, and hence gives no insight of how to build a capacity achieving code. After years of research, some advanced ECC systems as of 2016 come very close to the theoretical maximum.


title: Error correction code

text: In telecommunication, information theory, and coding theory, forward error correction (FEC) or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels. The central idea is that the sender encodes the message in a redundant way, most often by using an ECC.


title: Error correction code

text: The redundancy allows the receiver to detect a limited number of errors that may occur anywhere in the message, and often to correct these errors without re-transmission. FEC gives the receiver the ability to correct errors without needing a reverse channel to request re-transmission of data, but at the cost of a fixed, higher forward channel bandwidth. FEC is therefore applied in situations where re-transmissions are costly or impossible, such as one-way communication links and when transmitting to multiple receivers in multicast. FEC information is usually added to mass storage (magnetic, optical and solid state/flash based) devices to enable recovery of corrupted data, is widely used in modems, is used on systems where the primary memory is ECC memory and in broadcast situations, where the receiver does not have capabilities to request re-transmission or doing so would induce significant latency. For example, in the case of a satellite orbiting Uranus, a re-transmission because of decoding errors would create a delay of at least 5 hours.


title: Error correction code

text: FEC processing in a receiver may be applied to a digital bit stream or in the demodulation of a digitally modulated carrier. For the latter, FEC is an integral part of the initial analog-to-digital conversion in the receiver. The Viterbi decoder implements a soft-decision algorithm to demodulate digital data from an analog signal corrupted by noise. Many FEC coders can also generate a bit-error rate (BER) signal which can be used as feedback to fine-tune the analog receiving electronics.


title: Error correction code

text: The maximum proportion of errors or missing bits that can be corrected is determined by the design of the ECC, so different forward error correcting codes are suitable for different conditions. In general, a stronger code induces more redundancy that needs to be transmitted using the available bandwidth, which reduces the effective bit-rate while improving the received effective signal-to-noise ratio. The noisy-channel coding theorem of Claude Shannon answers the question of how much bandwidth is left for data communication while using the most efficient code that turns the decoding error probability to zero. This establishes bounds on the theoretical maximum information transfer rate of a channel with some given base noise level. His proof is not constructive, and hence gives no insight of how to build a capacity achieving code. However, after years of research, some advanced FEC systems like polar code achieve the Shannon channel capacity under the hypothesis of an infinite length frame.


title: Error correction code

text: ECC is accomplished by adding redundancy to the transmitted information using an algorithm. A redundant bit may be a complex function of many original information bits. The original information may or may not appear literally in the encoded output; codes that include the unmodified input in the output are systematic, while those that do not are non-systematic.


title: Error correction code

text: A simplistic example of ECC is to transmit each data bit 3 times, which is known as a (3,1) repetition code. Through a noisy channel, a receiver might see 8 versions of the output, see table below.


title: Error correction code

text: This allows an error in any one of the three samples to be corrected by "majority vote", or "democratic voting". The correcting ability of this ECC is:


title: Error correction code

text: Though simple to implement and widely used, this triple modular redundancy is a relatively inefficient ECC. Better ECC codes typically examine the last several tens or even the last several hundreds of previously received bits to determine how to decode the current small handful of bits (typically in groups of 2 to 8 bits).


title: Error correction code

text: ECC could be said to work by "averaging noise"; since each data bit affects many transmitted symbols, the corruption of some symbols by noise usually allows the original user data to be extracted from the other, uncorrupted received symbols that also depend on the same user data.


title: Error correction code

text: Most telecommunication systems use a fixed channel code designed to tolerate the expected worst-case bit error rate, and then fail to work at all if the bit error rate is ever worse.


title: Error correction code

text: However, some systems adapt to the given channel error conditions: some instances of hybrid automatic repeat-request use a fixed ECC method as long as the ECC can handle the error rate, then switch to ARQ when the error rate gets too high;


title: Error correction code

text: adaptive modulation and coding uses a variety of ECC rates, adding more error-correction bits per packet when there are higher error rates in the channel, or taking them out when they are not needed.


title: Error correction code

text: There are many types of block codes; Reed–Solomon coding is noteworthy for its widespread use in compact discs, DVDs, and hard disk drives. Other examples of classical block codes include Golay, BCH, Multidimensional parity, and Hamming codes.


title: Error correction code

text: Denser multi-level cell (MLC) NAND may use multi-bit correcting ECC such as BCH or Reed–Solomon. NOR Flash typically does not use any error correction.


title: Error correction code

text: Classical block codes are usually decoded using hard-decision algorithms, which means that for every input and output signal a hard decision is made whether it corresponds to a one or a zero bit. In contrast, convolutional codes are typically decoded using soft-decision algorithms like the Viterbi, MAP or BCJR algorithms, which process (discretized) analog signals, and which allow for much higher error-correction performance than hard-decision decoding.


title: Error correction code

text: Nearly all classical block codes apply the algebraic properties of finite fields. Hence classical block codes are often referred to as algebraic codes.


title: Error correction code

text: In contrast to classical block codes that often specify an error-detecting or error-correcting ability, many modern block codes such as LDPC codes lack such guarantees. Instead, modern codes are evaluated in terms of their bit error rates.


title: Error correction code

text: A few forward error correction codes are designed to correct bit-insertions and bit-deletions, such as Marker Codes and Watermark Codes.


title: Error correction code

text: The Levenshtein distance is a more appropriate way to measure the bit error rate when using such codes.


title: Error correction code

text: The fundamental principle of ECC is to add redundant bits in order to help the decoder to find out the true message that was encoded by the transmitter. The code-rate of a given ECC system is defined as the ratio between the number of information bits and the total number of bits (i.e., information plus redundancy bits) in a given communication package. The code-rate is hence a real number. A low code-rate close to zero implies a strong code that uses many redundant bits to achieve a good performance, while a large code-rate close to 1 implies a weak code.


title: Error correction code

text: The redundant bits that protect the information have to be transferred using the same communication resources that they are trying to protect. This causes a fundamental tradeoff between reliability and data rate. In one extreme, a strong code (with low code-rate) can induce an important increase in the receiver SNR (signal-to-noise-ratio) decreasing the bit error rate, at the cost of reducing the effective data rate. On the other extreme, not using any ECC (i.e., a code-rate equal to 1) uses the full channel for information transfer purposes, at the cost of leaving the bits without any additional protection.


title: Error correction code

text: One interesting question is the following: how efficient in terms of information transfer can an ECC be that has a negligible decoding error rate? This question was answered by Claude Shannon with his second theorem, which says that the channel capacity is the maximum bit rate achievable by any ECC whose error rate tends to zero: His proof relies on Gaussian random coding, which is not suitable to real-world applications. The upper bound given by Shannon's work inspired a long journey in designing ECCs that can come close to the ultimate performance boundary. Various codes today can attain almost the Shannon limit. However, capacity achieving ECCs are usually extremely complex to implement.


title: Error correction code

text: The most popular ECCs have a trade-off between performance and computational complexity. Usually, their parameters give a range of possible code rates, which can be optimized depending on the scenario. Usually, this optimization is done in order to achieve a low decoding error probability while minimizing the impact to the data rate. Another criterion for optimizing the code rate is to balance low error rate and retransmissions number in order to the energy cost of the communication.


title: Error correction code

text: Classical (algebraic) block codes and convolutional codes are frequently combined in concatenated coding schemes in which a short constraint-length Viterbi-decoded convolutional code does most of the work and a block code (usually Reed–Solomon) with larger symbol size and block length "mops up" any errors made by the convolutional decoder. Single pass decoding with this family of error correction codes can yield very low error rates, but for long range transmission conditions (like deep space) iterative decoding is recommended.


title: Error correction code

text: Concatenated codes have been standard practice in satellite and deep space communications since Voyager 2 first used the technique in its 1986 encounter with Uranus. The Galileo craft used iterative concatenated codes to compensate for the very high error rate conditions caused by having a failed antenna.


title: Error correction code

text: codes made from many single parity check (SPC) codes. They can provide performance very close to the channel capacity (the theoretical maximum) using an iterated soft-decision decoding approach, at linear time complexity in terms of their block length. Practical implementations rely heavily on decoding the constituent SPC codes in parallel.


title: Error correction code

text: but due to the computational effort in implementing encoder and decoder and the introduction of Reed–Solomon codes,


title: Error correction code

text: LDPC codes are now used in many recent high-speed communication standards, such as DVB-S2 (Digital Video Broadcasting – Satellite – Second Generation), WiMAX (IEEE 802.16e standard for microwave communications), High-Speed Wireless LAN (IEEE 802.11n), 10GBase-T Ethernet (802.3an) and G.hn/G.9960 (ITU-T Standard for networking over power lines, phone lines and coaxial cable). Other LDPC codes are standardized for wireless communication standards within 3GPP MBMS (see fountain codes).


title: Error correction code

text: Turbo coding is an iterated soft-decoding scheme that combines two or more relatively simple convolutional codes and an interleaver to produce a block code that can perform to within a fraction of a decibel of the Shannon limit. Predating LDPC codes in terms of practical application, they now provide similar performance.


title: Error correction code

text: One of the earliest commercial applications of turbo coding was the CDMA2000 1x (TIA IS-2000) digital cellular technology developed by Qualcomm and sold by Verizon Wireless, Sprint, and other carriers. It is also used for the evolution of CDMA2000 1x specifically for Internet access, 1xEV-DO (TIA IS-856). Like 1x, EV-DO was developed by Qualcomm, and is sold by Verizon Wireless, Sprint, and other carriers (Verizon's marketing name for 1xEV-DO is "Broadband Access", Sprint's consumer and business marketing names for 1xEV-DO are "Power Vision" and "Mobile Broadband", respectively).


title: Error correction code

text: Sometimes it is only necessary to decode single bits of the message, or to check whether a given signal is a codeword, and do so without looking at the entire signal. This can make sense in a streaming setting, where codewords are too large to be classically decoded fast enough and where only a few bits of the message are of interest for now. Also such codes have become an important tool in computational complexity theory, e.g., for the design of probabilistically checkable proofs.


title: Error correction code

text: Locally decodable codes are error-correcting codes for which single bits of the message can be probabilistically recovered by only looking at a small (say constant) number of positions of a codeword, even after the codeword has been corrupted at some constant fraction of positions. Locally testable codes are error-correcting codes for which it can be checked probabilistically whether a signal is close to a codeword by only looking at a small number of positions of the signal.


title: Error correction code

text: Interleaving is frequently used in digital communication and storage systems to improve the performance of forward error correcting codes. Many communication channels are not memoryless: errors typically occur in bursts rather than independently. If the number of errors within a code word exceeds the error-correcting code's capability, it fails to recover the original code word. Interleaving alleviates this problem by shuffling source symbols across several code words, thereby creating a more uniform distribution of errors. Therefore, interleaving is widely used for burst error-correction.


title: Error correction code

text: The analysis of modern iterated codes, like turbo codes and LDPC codes, typically assumes an independent distribution of errors. Systems using LDPC codes therefore typically employ additional interleaving across the symbols within a code word.


title: Error correction code

text: For turbo codes, an interleaver is an integral component and its proper design is crucial for good performance. The iterative decoding algorithm works best when there are not short cycles in the factor graph that represents the decoder; the interleaver is chosen to avoid short cycles.


title: Error correction code

text: In multi-carrier communication systems, interleaving across carriers may be employed to provide frequency diversity, e.g., to mitigate frequency-selective fading or narrowband interference.


title: Error correction code

text: Here, each group of the same letter represents a 4-bit one-bit error-correcting codeword. The codeword is altered in one bit and can be corrected, but the codeword is altered in three bits, so either it cannot be decoded at all or it might be decoded incorrectly.


title: Error correction code

text: In each of the codewords "", "", "", and "", only one bit is altered, so one-bit error-correcting code will decode everything correctly.


title: Error correction code

text: Use of interleaving techniques increases total delay. This is because the entire interleaved block must be received before the packets can be decoded. Also interleavers hide the structure of errors; without an interleaver, more advanced decoding algorithms can take advantage of the error structure and achieve more reliable communication than a simpler decoder combined with an interleaver. An example of such an algorithm is based on neural network structures.


title: Error correction code

text: Simulating the behaviour of error-correcting codes (ECCs) in software is a common practice to design, validate and improve ECCs. The upcoming wireless 5G standard raises a new range of applications for the software ECCs: the Cloud Radio Access Networks (C-RAN) in a Software-defined radio (SDR) context. The idea is to directly use software ECCs in the communications. For instance in the 5G, the software ECCs could be located in the cloud and the antennas connected to this computing resources: improving this way the flexibility of the communication network and eventually increasing the energy efficiency of the system.


title: Nor'easter

text: A nor'easter (also northeaster; see below), or an East Coast low is a synoptic-scale extratropical cyclone in the western North Atlantic Ocean. The name derives from the direction of the winds that blow from the northeast. The original use of the term in North America is associated with storms that impact the upper north Atlantic coast of the United States and the Atlantic Provinces of Canada.


title: Nor'easter

text: Typically, such storms originate as a low-pressure area that forms within of the shore between North Carolina and Massachusetts. The precipitation pattern is similar to that of other extratropical storms. Nor'easters are usually accompanied by heavy rain or snow, and can cause severe coastal flooding, coastal erosion, hurricane-force winds, or blizzard conditions. Nor'easters are usually most intense during winter in New England and Atlantic Canada. They thrive on converging air masses—the cold polar air mass and the warmer air over the water—and are more severe in winter when the difference in temperature between these air masses is greater.


title: Nor'easter

text: Nor'easters tend to develop most often and most powerfully between the months of November and March, although they can (much less commonly) develop during other parts of the year as well. The susceptible regions are generally impacted by nor'easters a few times each winter.


title: Nor'easter

text: The term "nor'easter" came to American English by way of British English. Early recorded uses of the contraction "nor" (for "north") in combinations such as "nor'-east" and "nor-nor-west", as reported by the "Oxford English Dictionary", date to the late 16th century, as in John Davis's 1594 "The Seaman's Secrets": "Noreast by North raiseth a degree in sayling 24 leagues." The spelling appears, for instance, on a compass card published in 1607. Thus, the manner of pronouncing from memory the 32 points of the compass, known in maritime training as "boxing the compass", is described by Ansted with pronunciations "Nor'east (or west)," "Nor' Nor'-east (or west)," "Nor'east b' east (or west)," and so forth. According to the OED, the first recorded use of the term "nor'easter" occurs in 1836 in a translation of Aristophanes. The term "nor'easter" naturally developed from the historical spellings and pronunciations of the compass points and the direction of wind or sailing.


title: Nor'easter

text: As noted in a January 2006 editorial by William Sisson, editor of "Soundings" magazine, use of "nor'easter" to describe the storm system is common along the U.S. East Coast. Yet it has been asserted by linguist Mark Liberman (see below) that "nor'easter" as a contraction for "northeaster" has no basis in regional New England dialect; the Boston accent would elide the "R": "no'theastuh"'. He describes nor'easter as a "fake" word. However, this view neglects the little-known etymology and the historical maritime usage described above.


title: Nor'easter

text: 19th-century Downeast mariners pronounced the compass point "north northeast" as "no'nuth-east", and so on. For decades, Edgar Comee, of Brunswick, Maine, waged a determined battle against use of the term "nor'easter" by the press, which usage he considered "a pretentious and altogether lamentable affectation" and "the odious, even loathsome, practice of landlubbers who would be seen as salty as the sea itself". His efforts, which included mailing hundreds of postcards, were profiled, just before his death in 2005 at the age of 88, in "The New Yorker".


title: Nor'easter

text: Despite the efforts of Comee and others, use of the term continues by the press. According to "Boston Globe" writer Jan Freeman, "from 1975 to 1980, journalists used the nor’easter spelling only once in five mentions of such storms; in the past year (2003), more than 80 percent of northeasters were spelled nor'easter".


title: Nor'easter

text: University of Pennsylvania linguistics professor Mark Liberman has pointed out that while the Oxford English Dictionary cites examples dating back to 1837, these examples represent the contributions of a handful of non-New England poets and writers. Liberman posits that "nor'easter" may have originally been a literary affectation, akin to "e'en" for "even" and "th'only" for "the only", which is an indication in spelling that two syllables count for only one position in metered verse, with no implications for actual pronunciation.


title: Nor'easter

text: However, despite these assertions, the term can be found in the writings of New Englanders, and was frequently used by the press in the 19th century.


title: Nor'easter

text: The Pacific Northwest is also affected by a similar class of powerful extratropical cyclones, known as Pacific Northwest windstorms. While the storms on the East Coast are named "nor'easters", the Pacific Northwest windstorms are not called "nor'westers" because the cyclones' primary winds can blow from any direction, while the primary winds in nor'easters usually blow from the northeast.


title: Nor'easter

text: Nor'easters develop in response to the sharp contrast in the warm Gulf Stream ocean current coming up from the tropical Atlantic and the cold air masses coming down from Canada. Very cold and dry air rushing southward and meeting up with the warm Gulf stream current, which is typically near even mid-winter, often causes low-pressure areas to develop and intensify.


title: Nor'easter

text: In the upper atmosphere, the strong winds of the jet stream remove and replace rising air from the Atlantic more rapidly than the Atlantic air is replaced at lower levels; this and the Coriolis force help develop a strong storm. The storm tracks northeast along the East Coast, normally from North Carolina to Long Island, then moves toward the area east of Cape Cod. Counterclockwise winds around the low-pressure system blow the moist air over land. The relatively warm, moist air meets cold air coming southward from Canada. The low increases the surrounding pressure difference, which causes the very different air masses to collide at a faster speed. When the difference in temperature of the air masses is larger, so is the storm's instability, turbulence, and thus severity.


title: Nor'easter

text: The nor'easters taking the East Coast track usually indicates the presence of a high-pressure area in the vicinity of Nova Scotia. Sometimes a nor'easter will move slightly inland and bring rain to the cities on the coastal plain (New York City, Philadelphia, Baltimore, etc.) and snow in New England (Boston northward). On occasion, nor'easters can pull cold air as far south as Virginia or North Carolina, bringing wet snow inland in those areas for a brief time. Such a storm will rapidly intensify, tracking northward and following the topography of the East Coast, sometimes continuing to grow stronger during its entire existence. A nor'easter usually reaches its peak intensity while off the Canadian coast. The storm then reaches Arctic areas, and can reach intensities equal to that of a weak hurricane. It then meanders throughout the North Atlantic and can last for several weeks.


title: Nor'easter

text: Meteorologists use the Miller Classification to determine the track and severity of a nor'easter. The technique is named after J.E. Miller, who created the system in 1946. The Miller Classification classified storms into two categories: Type A and Type B. Type A storms form in the Gulf of Mexico or along the coast of Georgia or South Carolina, and cause heavy snow mainly to parts of the Mid-Atlantic, New England, and Atlantic Canada. Type B storms form from a parent low-pressure system over the Ohio Valley, which then undergoes a center reformation onto the Gulf Stream. These storms can bring a swath of wintry precipitation from the Great Plains and the Ohio River Valley to the Southeastern United States and New England.


title: Nor'easter

text: Nor'easters are usually formed by an area of vorticity associated with an upper-level disturbance or from a kink in a frontal surface that causes a surface low-pressure area to develop. Such storms are very often formed from the merging of several weaker storms, a "parent storm", and a polar jet stream mixing with the tropical jet stream.


title: Nor'easter

text: Temperatures usually fall significantly due to the presence of the cooler air from winds that typically come from a northeasterly direction. During a single storm, the precipitation can range from a torrential downpour to a fine mist. All precipitation types can occur in a nor'easter. High wind gusts, which can reach hurricane strength, are also associated with a nor'easter. On very rare occasions, such as in the nor'easter in 1978, North American blizzard of 2006, Early February 2013 North American blizzard, and January 2018 North American blizzard, the center of the storm can take on the circular shape more typical of a hurricane and have a small "dry slot" near the center, which can be mistaken for an eye, although it is not an eye.


title: Nor'easter

text: Often, people mistake nor'easters for tropical cyclones and do not differentiate between the two weather systems. Nor'easters differ from tropical cyclones in that nor'easters are cold-core low-pressure systems, meaning that they thrive on drastic changes in temperature of Canadian air and warm Atlantic waters. Tropical cyclones are warm-core low-pressure systems, which means they thrive on purely warm temperatures. However, in rare cases, such as the 1991 Perfect Storm, a small tropical cyclone can develop inside the warm seclusion of an intense nor'easter if the sea surface temperatures are sufficiently warm. Nor'easters can rarely also turn into tropical or subtropical cyclones, such as 2021's Tropical Storm Wanda.


title: Nor'easter

text: A nor'easter is a strong extratropical cyclone, often experiencing explosive cyclogenesis. While this formation occurs in many places around the world, nor'easters are unique for their combination of northeast winds and moisture content of the swirling clouds. Nearly similar conditions sometimes occur during winter in the Pacific Northeast (northern Japan and northwards) with winds from NNW. In Europe, similar weather systems with such severity are hardly possible; the moisture content of the clouds is usually not high enough to cause flooding or heavy snow, although northeasterly winds can be strong.


title: Nor'easter

text: The eastern United States, from North Carolina to Maine, and Eastern Canada can experience nor'easters, though most often they affect the areas from New England northward. The effects of a nor'easter sometimes bring high surf and strong winds as far south as coastal South Carolina. Nor'easters cause a significant amount of beach erosion in these areas, as well as flooding in the associated low-lying areas.


title: Nor'easter

text: Biologists at the Woods Hole Oceanographic Institution on Cape Cod have determined nor'easters are an environmental factor for red tides on the Atlantic coast.


title: Paleocene

text: The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek "palaiós" meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene".


title: Paleocene

text: The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact and possibly volcanism, marked the beginning of the Paleocene and killed off 75% of living species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification.


title: Paleocene

text: In the Paleocene, the continents of the Northern Hemisphere were still connected via some land bridges; and South America, Antarctica, and Australia had not completely separated yet. The Rocky Mountains were being uplifted, the Americas had not yet joined, the Indian Plate had begun its collision with Asia, and the North Atlantic Igneous Province was forming in the third-largest magmatic event of the last 150 million years. In the oceans, the thermohaline circulation probably was much different from what it is today, with downwellings occurring in the North Pacific rather than the North Atlantic, and water density mainly being controlled by salinity rather than temperature.


title: Paleocene

text: The K–Pg extinction event caused a floral and faunal turnover of species, with previously abundant species being replaced by previously uncommon ones. In the Paleocene, with a global average temperature of about , compared to in more recent times, the Earth had a greenhouse climate without permanent ice sheets at the poles, like the preceding Mesozoic. As such, there were forests worldwide—including at the poles—but they had low species richness in regards to plant life, and were populated by mainly small creatures that were rapidly evolving to take advantage of the recently emptied Earth. Though some animals attained great size, most remained rather small. The forests grew quite dense in the general absence of large herbivores. Mammals proliferated in the Paleocene, and the earliest placental and marsupial mammals are recorded from this time, but most Paleocene taxa have ambiguous affinities. In the seas, ray-finned fish rose to dominate open ocean and reef ecosystems.


title: Paleocene

text: The word "Paleocene" was first used by French paleobotanist and geologist Wilhelm Philipp Schimper in 1874 while describing deposits near Paris (spelled in his treatise). By this time, Italian geologist Giovanni Arduino had divided the history of life on Earth into the Primary (Paleozoic), Secondary (Mesozoic), and Tertiary in 1759; French geologist Jules Desnoyers had proposed splitting off the Quaternary from the Tertiary in 1829; and Scottish geologist Charles Lyell (ignoring the Quaternary) had divided the Tertiary Epoch into the Eocene, Miocene, Pliocene, and New Pliocene (Holocene) Periods in 1833. British geologist John Phillips had proposed the Cenozoic in 1840 in place of the Tertiary, and Austrian paleontologist Moritz Hörnes had introduced the Paleogene for the Eocene and Neogene for the Miocene and Pliocene in 1853. After decades of inconsistent usage, the newly formed International Commission on Stratigraphy (ICS), in 1969, standardized stratigraphy based on the prevailing opinions in Europe: the Cenozoic Era subdivided into the Tertiary and Quaternary sub-eras, and the Tertiary subdivided into the Paleogene and Neogene Periods. In 1978, the Paleogene was officially defined as the Paleocene, Eocene, and Oligocene Epochs; and the Neogene as the Miocene and Pliocene Epochs. In 1989, Tertiary and Quaternary were removed from the time scale due to the arbitrary nature of their boundary, but Quaternary was reinstated in 2009, which may lead to the reinstatement of the Tertiary in the future.


title: Paleocene

text: The term "Paleocene" is a portmanteau combination of the Ancient Greek "palaios" meaning "old", and the word "Eocene", and so means "the old part of the Eocene". The Eocene, in turn, is derived from Ancient Greek eo—"eos" meaning "dawn", and—cene "kainos" meaning "new" or "recent", as the epoch saw the dawn of recent, or modern, life. Paleocene did not come into broad usage until around 1920. In North America and mainland Europe, the standard spelling is "Paleocene", whereas it is "Palaeocene" in the UK. Geologist T. C. R. Pulvertaft has argued that the latter spelling is incorrect because this would imply either a translation of "old recent" or a derivation from "pala" and "Eocene", which would be incorrect because the prefix palæo- uses the ligature æ instead of "a" and "e" individually, so only both characters or neither should be dropped, not just one.


title: Paleocene

text: The Paleocene Epoch is the 10 million year time interval directly after the K–Pg extinction event, which ended the Cretaceous Period and the Mesozoic Era, and initiated the Cenozoic Era and the Paleogene Period. It is divided into three ages: the Danian spanning 66 to 61.6 million years ago (mya), the Selandian spanning 61.6 to 59.2 mya, and the Thanetian spanning 59.2 to 56 mya. It is succeeded by the Eocene.


title: Paleocene

text: The K–Pg boundary is clearly defined in the fossil record in numerous places around the world by a high-iridium band, as well as discontinuities with fossil flora and fauna. It is generally thought that a wide asteroid impact, forming the Chicxulub Crater in the Yucatán Peninsula in the Gulf of Mexico, and Deccan Trap volcanism caused a cataclysmic event at the boundary resulting in the extinction of 75% of all species.


title: Paleocene

text: The Paleocene ended with the Paleocene–Eocene thermal maximum, a short period of intense warming and ocean acidification brought about by the release of carbon en masse into the atmosphere and ocean systems, which led to a mass extinction of 30–50% of benthic foraminifera–planktonic species which are used as bioindicators of the health of a marine ecosystem—one of the largest in the Cenozoic. This event happened around 55.8 mya, and was one of the most significant periods of global change during the Cenozoic.


title: Paleocene

text: Geologists divide the rocks of the Paleocene into a stratigraphic set of smaller rock units called stages, each formed during corresponding time intervals called ages. Stages can be defined globally or regionally. For "global" stratigraphic correlation, the ICS ratify global stages based on a Global Boundary Stratotype Section and Point (GSSP) from a single formation (a stratotype) identifying the lower boundary of the stage. In 1989, the ICS decided to split the Paleocene into three stages: the Danian, Selandian, and Thanetian.


title: Paleocene

text: The Danian was first defined in 1847 by German-Swiss geologist Pierre Jean Édouard Desor based on the Danish chalks at Stevns Klint and Faxse, and was part of the Cretaceous, succeeded by the Tertiary Montian Stage. In 1982, after it was shown that the Danian and the Montian are the same, the ICS decided to define the Danian as starting with the K–Pg boundary, thus ending the practice of including the Danian in the Cretaceous. In 1991, the GSSP was defined as a well-preserved section in the El Haria Formation near El Kef, Tunisia, , and the proposal was officially published in 2006.


title: Paleocene

text: The Selandian and Thanetian are both defined in Itzurun beach by the Basque town of Zumaia, , as the area is a continuous early Santonian to early Eocene sea cliff outcrop. The Paleocene section is an essentially complete, exposed record thick, mainly composed of alternating hemipelagic sediments deposited at a depth of about . The Danian deposits are sequestered into the Aitzgorri Limestone Formation, and the Selandian and early Thanetian into the Itzurun Formation. The Itzurun Formation is divided into groups A and B corresponding to the two stages respectively. The two stages were ratified in 2008, and this area was chosen because of its completion, low risk of erosion, proximity to the original areas the stages were defined, accessibility, and the protected status of the area due to its geological significance.


title: Paleocene

text: The Selandian was first proposed by Danish geologist Alfred Rosenkrantz in 1924 based on a section of fossil-rich glauconitic marls overlain by gray clay which unconformably overlies Danian chalk and limestone. The area is now subdivided into the Æbelø Formation, Holmehus Formation, and the Østerrende Clay. The beginning of this stage was defined by the end of carbonate rock deposition from an open ocean environment in the North Sea region (which had been going on for the previous 40 million years). The Selandian deposits in this area are directly overlain by the Eocene Fur Formation—the Thanetian was not represented here—and this discontinuity in the deposition record is why the GSSP was moved to Zumaia. Today, the beginning of the Selandian is marked by the appearances of the nannofossils "Fasciculithus tympaniformis", "Neochiastozygus perfectus", and "Chiasmolithus edentulus", though some foraminifera are used by various authors.


title: Paleocene

text: The Thanetian was first proposed by Swiss geologist Eugène Renevier, in 1873; he included the south England Thanet, Woolwich, and Reading formations. In 1880, French geologist Gustave Frédéric Dollfus narrowed the definition to just the Thanet Formation. The Thanetian begins a little after the mid-Paleocene biotic event—a short-lived climatic event caused by an increase in methane—recorded at Itzurun as a dark interval from a reduction of calcium carbonate. At Itzurun, it begins about above the base of the Selandian, and is marked by the first appearance of the algae "Discoaster" and a diversification of "Heliolithus", though the best correlation is in terms of paleomagnetism. A chron is the occurrence of a geomagnetic reversal—when the North and South poles switch polarities. Chron 1 (C1n) is defined as modern day to about 780,000 years ago, and the n denotes "normal" as in the polarity of today, and an r "reverse" for the opposite polarity. The beginning of the Thanetian is best correlated with the C26r/C26n reversal.


title: Paleocene

text: Several economically important coal deposits formed during the Paleocene, such as the sub-bituminous Fort Union Formation in the Powder River Basin of Wyoming and Montana, which produces 43% of American coal; the Wilcox Group in Texas, the richest deposits of the Gulf Coastal Plain; and the Cerrejón mine in Colombia, the largest open-pit mine in the world. Paleocene coal has been mined extensively in Svalbard, Norway, since near the beginning of the 20th century, and late Paleocene and early Eocene coal is widely distributed across the Canadian Arctic Archipelago and northern Siberia. In the North Sea, Paleocene-derived natural gas reserves, when they were discovered, totaled approximately 2.23 trillion m (7.89 trillion ft), and oil in place 13.54 billion barrels. Important phosphate deposits—predominantly of francolite—near Métlaoui, Tunisia were formed from the late Paleocene to the early Eocene.


title: Paleocene

text: Impact craters formed in the Paleocene include: the Connolly Basin crater in Western Australia less than 60 mya, the Texan Marquez crater 58 mya, and possibly the Jordan Jabel Waqf as Suwwan crater which dates to between 56 and 37 mya. Vanadium-rich osbornite from the Isle of Skye, Scotland, dating to 60 mya may be impact ejecta. Craters were also formed near the K–Pg boundary, the largest the Mexican Chicxulub crater whose impact was a major precipitator of the K–Pg extinction, and also the Ukrainian Boltysh crater, dated to 65.4 mya the Canadian Eagle Butte crater (though it may be younger), the Vista Alegre crater (though this may date to about 115 mya). Silicate glass spherules along the Atlantic coast of the U.S. indicate a meteor impact in the region at the PETM. The buried Hiawatha Glacier crater in Greenland has been dated to the late Paleocene, around 58 mya.


title: Paleocene

text: During the Paleocene, the continents continued to drift toward their present positions. In the Northern Hemisphere, the former components of Laurasia (North America and Eurasia) were, at times, connected via land bridges: Beringia (at 65.5 and 58 mya) between North America and East Asia, the De Geer route (from 71 to 63 mya) between Greenland and Scandinavia, the Thulean route (at 57 and 55.8 mya) between North America and Western Europe via Greenland, and the Turgai route connecting Europe with Asia (which were otherwise separated by the Turgai Strait at this time).


title: Paleocene

text: The Laramide orogeny, which began in the Late Cretaceous, continued to uplift the Rocky Mountains; it ended at the end of the Paleocene. Because of this and a drop in sea levels resulting from tectonic activity, the Western Interior Seaway, which had divided the continent of North America for much of the Cretaceous, had receded.


title: Paleocene

text: Between about 60.5 and 54.5 mya, there was heightened volcanic activity in the North Atlantic region—the third largest magmatic event in the last 150 million years—creating the North Atlantic Igneous Province. The proto-Iceland hotspot is sometimes cited as being responsible for the initial volcanism, though rifting and resulting volcanism have also contributed. This volcanism may have contributed to the opening of the North Atlantic Ocean and seafloor spreading, the divergence of the Greenland Plate from the North American Plate, and, climatically, the PETM by dissociating methane clathrate crystals on the seafloor resulting in the mass release of carbon.


title: Paleocene

text: North and South America remained separated by the Central American Seaway, though an island arc (the South Central American Arc) had already formed about 73 mya. The Caribbean Large Igneous Province (now the Caribbean Plate), which had formed from the Galápagos hotspot in the Pacific in the latest Cretaceous, was moving eastward as the North American and South American plates were getting pushed in the opposite direction due to the opening of the Atlantic (strike-slip tectonics). This motion would eventually uplift the Isthmus of Panama by 2.6 mya. The Caribbean Plate continued moving until about 50 mya when it reached its current position.


title: Paleocene

text: The components of the former southern supercontinent Gondwanaland in the Southern Hemisphere continued to drift apart, but Antarctica was still connected to South America and Australia. Africa was heading north towards Europe, and the Indian subcontinent towards Asia, which would eventually close the Tethys Ocean. The Indian and Eurasian Plates began colliding sometime in the Paleocene or Eocene with uplift (and a land connection) beginning in the Miocene about 24–17 mya. There is evidence that some plants and animals could migrate between India and Asia during the Paleocene, possibly via intermediary island arcs.


title: Paleocene

text: In the modern thermohaline circulation, warm tropical water becomes colder and saltier at the poles and sinks (downwelling or deep water formation) that occurs at the North Atlantic near the North Pole and the Southern Ocean near the Antarctic Peninsula. In the Paleocene, the waterways between the Arctic Ocean and the North Atlantic were somewhat restricted, so North Atlantic Deep Water (NADW) and the Atlantic Meridional Overturning Circulation (AMOC)—which circulates cold water from the Arctic towards the equator—had not yet formed, and so deep water formation probably did not occur in the North Atlantic. The Arctic and Atlantic would not be connected by sufficiently deep waters until the early to middle Eocene.


title: Paleocene

text: There is evidence of deep water formation in the North Pacific to at least a depth of about . The elevated global deep water temperatures in the Paleocene may have been too warm for thermohaline circulation to be predominately heat driven. It is possible that the greenhouse climate shifted precipitation patterns, such that the Southern Hemisphere was wetter than the Northern, or the Southern experienced less evaporation than the Northern. In either case, this would have made the Northern more saline than the Southern, creating a density difference and a downwelling in the North Pacific traveling southward. Deep water formation may have also occurred in the South Atlantic.


title: Paleocene

text: It is largely unknown how global currents could have affected global temperature. The formation of the Northern Component Waters by Greenland in the Eocene—the predecessor of the AMOC—may have caused an intense warming in the North Hemisphere and cooling in the Southern, as well as an increase in deep water temperatures. In the PETM, it is possible deep water formation occurred in saltier tropical waters and moved polewards, which would increase global surface temperatures by warming the poles. Also, Antarctica was still connected to South America and Australia, and, because of this, the Antarctic Circumpolar Current—which traps cold water around the continent and prevents warm equatorial water from entering—had not yet formed. Its formation may have been related in the freezing of the continent. Warm coastal upwellings at the poles would have inhibited permanent ice cover. Conversely, it is possible deep water circulation was not a major contributor to the greenhouse climate, and deep water temperatures more likely change as a response to global temperature change rather than affecting it.


title: Paleocene

text: In the Arctic, coastal upwelling may have been largely temperature and wind-driven. In summer, the land surface temperature was probably higher than oceanic temperature, and the opposite was true in the winter, which is consistent with monsoon seasons in Asia. Open-ocean upwelling may have also been possible.


title: Paleocene

text: The Paleocene climate was, much like in the Cretaceous, tropical or subtropical, and the poles were temperate and ice free with an average global temperature of roughly . For comparison, the average global temperature for the period between 1951 and 1980 was . A 2019 study identified changes in orbital eccentricity as the dominant drivers of climate between the late Cretaceous and the early Eocene.


title: Paleocene

text: Global deep water temperatures in the Paleocene likely ranged from , compared to in modern day. Based on the upper limit, average sea surface temperatures at 60°N and S would have been the same as deep sea temperatures, at 30°N and S about , and at the equator about . The Paleocene foraminifera assemblage globally indicates a defined deep-water thermocline (a warmer mass of water closer to the surface sitting on top of a colder mass nearer the bottom) persisting throughout the epoch. The Atlantic foraminifera indicate a general warming of sea surface temperature–with tropical taxa present in higher latitude areas–until the Late Paleocene when the thermocline became steeper and tropical foraminifera retreated back to lower latitudes.


title: Paleocene

text: Early Paleocene atmospheric CO levels at what is now Castle Rock, Colorado, were calculated to be between 352 and 1,110 parts per million (ppm), with a median of 616 ppm. Based on this and estimated plant-gas exchange rates and global surface temperatures, the climate sensitivity was calculated to be +3 °C when CO levels doubled, compared to 7° following the formation of ice at the poles. CO levels alone may have been insufficient in maintaining the greenhouse climate, and some positive feedbacks must have been active, such as some combination of cloud, aerosol, or vegetation related processes.


title: Paleocene

text: The poles probably had a cool temperate climate; northern Antarctica, Australia, the southern tip of South America, what is now the US and Canada, eastern Siberia, and Europe warm temperate; middle South America, southern and northern Africa, South India, Middle America, and China arid; and northern South America, central Africa, North India, middle Siberia, and what is now the Mediterranean Sea tropical.


title: Paleocene

text: The effects of the meteor impact and volcanism 66 mya and the climate across the K–Pg boundary were likely fleeting, and climate reverted to normal in a short time frame. The freezing temperatures probably reversed after 3 years and returned to normal within decades, sulfuric acid aerosols causing acid rain probably dissipated after 10 years, and dust from the impact blocking out sunlight and inhibiting photosynthesis would have lasted up to a year though potential global wildfires raging for several years would have released more particulates into the atmosphere. For the following half million years, the carbon isotope gradient—a difference in the C/C ratio between surface and deep ocean water, causing carbon to cycle into the deep sea—may have shut down. This, termed a "Strangelove ocean", indicates low oceanic productivity; resultant decreased phytoplankton activity may have led to a reduction in cloud seeds and, thus, marine cloud brightening, causing global temperatures to increase by 6 °C (CLAW hypothesis).


title: Paleocene

text: The Dan–C2 Event 65.2 mya in the early Danian spanned about 100,000 years, and was characterized by an increase in carbon, particularly in the deep sea. Since the mid-Maastrichtian, more and more carbon had been sequestered in the deep sea possibly due to a global cooling trend and increased circulation into the deep sea. The Dan–C2 event may represent a release of this carbon after deep sea temperatures rose to a certain threshold, as warmer water can dissolve a lesser amount of carbon. Savanna may have temporarily displaced forestland in this interval.


title: Paleocene

text: Around 62.2 mya in the late Danian, there was a warming event and evidence of ocean acidification associated with an increase in carbon; at this time, there was major seafloor spreading in the Atlantic and volcanic activity along the southeast margin of Greenland. The Latest Danian Event, also known as the Top Chron C27n Event, lasted about 200,000 years and resulted in a 1.6–2.8 °C increase in temperatures throughout the water column. Though the temperature in the latest Danian varied at about the same magnitude, this event coincides with an increase of carbon.


title: Paleocene

text: About 60.5 mya at the Danian/Selandian boundary, there is evidence of anoxia spreading out into coastal waters, and a drop in sea levels which is most likely explained as an increase in temperature and evaporation, as there was no ice at the poles to lock up water.


title: Paleocene

text: During the mid-Paleocene biotic event (MPBE) around 59 mya (roughly 50,000 years before the Selandian/Thanetian boundary), the temperature spiked probably due to a mass release of the deep sea methane hydrate into the atmosphere and ocean systems. Carbon was probably output for 10–11,000 years, and the aftereffects likely subsided around 52–53,000 years later. There is also evidence this occurred again 300,000 years later in the early Thanetian dubbed MPBE-2. Respectively, about 83 and 132 gigatons of methane-derived carbon were ejected into the atmosphere, which suggests a 2–3 °C (3.6–5.4 °F) rise in temperature, and likely caused heightened seasonality and less stable environmental conditions. It may have also caused an increase of grass in some areas.


title: Paleocene

text: The Paleocene–Eocene Thermal Maximum was an approximately 200,000-year-long event where the global average temperature rose by some 5 to 8 °C (9 to 14 °F), and mid-latitude and polar areas may have exceeded modern tropical temperatures of . This was due to an ejection of 2,500–4,500 gigatons of carbon into the atmosphere, most commonly explained as the perturbation and release of methane clathrate deposits in the North Atlantic from tectonic activity and resultant increase in bottom water temperatures. Other proposed hypotheses include methane release from the heating of organic matter at the seafloor rather than methane clathrates, or melting permafrost. The duration of carbon output is controversial, but most likely about 2,500 years. This carbon also interfered with the carbon cycle and caused ocean acidification, and potentially altered and slowed down ocean currents, the latter leading to the expansion of oxygen minimum zones (OMZs) in the deep sea. In surface water, OMZs could have also been caused from the formation of strong thermoclines preventing oxygen inflow, and higher temperatures equated to higher productivity leading to higher oxygen usurpation. Further, expanding OMZs could have caused the proliferation of sulfate-reducing microorganisms which create highly toxic hydrogen sulfide HS as a waste product. During the event, the volume of sulfidic water may have been 10–20% of total ocean volume, in comparison to today's 1%. This may have also caused chemocline upwellings along continents and the dispersal of HS into the atmosphere. During the PETM there was a temporary dwarfing of mammals apparently caused by the upward excursion in temperature.


title: Paleocene

text: The warm, wet climate supported tropical and subtropical forests worldwide, mainly populated by conifers and broad-leafed trees. In Patagonia, the landscape supported tropical rainforests, cloud rainforests, mangrove forests, swamp forests, savannas, and sclerophyllous forests. In the Colombian Cerrejón Formation, fossil flora belong to the same families as modern day flora—such as palm trees, legumes, aroids, and malvales—and the same is true in the North Dakotan Almont/Beicegel Creek—such as Ochnaceae, "Cyclocarya", and "Ginkgo cranei"—indicating the same floral families have characterized South American rainforests and the American Western Interior since the Paleocene.


title: Paleocene

text: The extinction of large herbivorous dinosaurs may have allowed the forests to grow quite dense, and there is little evidence of wide open plains. Plants evolved several techniques to cope with high plant density, such as buttressing to better absorb nutrients and compete with other plants, increased height to reach sunlight, larger diaspore in seeds to provide added nutrition on the dark forest floor, and epiphytism where a plant grows on another plant in response to less space on the forest floor. Despite increasing density—which could act as fuel—wildfires decreased in frequency from the Cretaceous to the early Eocene as the atmospheric oxygen levels decreased to modern day levels, though they may have been more intense.


title: Paleocene

text: There was a major die-off of plant species over the boundary; for example, in the Williston Basin of North Dakota, an estimated 1/3 to 3/5 of plant species went extinct. The K–Pg extinction event ushered in a floral turnover; for example, the once commonplace Araucariaceae conifers were almost fully replaced by Podocarpaceae conifers, and the Cheirolepidiaceae, a group of conifers that had dominated during most of the Mesozoic but had become rare during the Late Cretaceous became dominant trees in Patagonia, before going extinct. Some plant communities, such as those in eastern North America, were already experiencing an extinction event in the late Maastrichtian, particularly in the 1 million years before the K–Pg extinction event. The "disaster plants" that refilled the emptied landscape crowded out many Cretaceous plants, and resultantly, many went extinct by the middle Paleocene.


title: Paleocene

text: The strata immediately overlaying the K–Pg extinction event are especially rich in fern fossils. Ferns are often the first species to colonize areas damaged by forest fires, so this "fern spike" may mark the recovery of the biosphere following the impact (which caused blazing fires worldwide). The diversifying herb flora of the early Paleocene either represent pioneer species which re-colonized the recently emptied landscape, or a response to the increased amount of shade provided in a forested landscape. Lycopods, ferns, and angiosperm shrubs may have been important components of the Paleocene understory.


title: Paleocene

text: In general, the forests of the Paleocene were species-poor, and diversity did not fully recover until the end of the Paleocene. For example, the floral diversity of what is now the Holarctic region (comprising most of the Northern Hemisphere) was mainly early members of "Ginkgo", "Metasequoia", "Glyptostrobus", "Macginitiea", "Platanus", "Carya", "Ampelopsis", and "Cercidiphyllum". Patterns in plant recovery varied significantly with latitude, climate, and altitude. For example, what is now Castle Rock, Colorado featured a rich rainforest only 1.4 million years after the event, probably due to a rain shadow effect causing regular monsoon seasons. Conversely, low plant diversity and a lack of specialization in insects in the Colombian Cerrejón Formation, dated to 58 mya, indicates the ecosystem was still recovering from the K–Pg extinction event 7 million years later.


title: Paleocene

text: Flowering plants (angiosperms), which had become dominant among forest taxa by the middle Cretaceous 110–90 mya, continued to develop and proliferate, more so to take advantage of the recently emptied niches and an increase in rainfall. Along with them coevolved the insects that fed on these plants and pollinated them. Predation by insects was especially high during the PETM. Many fruit-bearing plants appeared in the Paleocene in particular, probably to take advantage of the newly evolving birds and mammals for .


title: Paleocene

text: In what is now the Gulf Coast, angiosperm diversity increased slowly in the early Paleocene, and more rapidly in the middle and late Paleocene. This may have been because the effects of the K–Pg extinction event were still to some extent felt in the early Paleocene, the early Paleocene may not have had as many open niches, early angiosperms may not have been able to evolve at such an accelerated rate as later angiosperms, low diversity equates to lower evolution rates, or there was not much angiosperm migration into the region in the early Paleocene. Over the K–Pg extinction event, angiosperms had a higher extinction rate than gymnosperms (which include conifers, cycads, and relatives) and pteridophytes (ferns, horsetails, and relatives); zoophilous angiosperms (those that relied on animals for pollination) had a higher rate than anemophilous angiosperms; and evergreen angiosperms had a higher rate than deciduous angiosperms as deciduous plants can become dormant in harsh conditions.


title: Paleocene

text: In the Gulf Coast, angiosperms experienced another extinction event during the PETM, which they recovered quickly from in the Eocene through immigration from the Caribbean and Europe. During this time, the climate became warmer and wetter, and it is possible that angiosperms evolved to become stenotopic by this time, able to inhabit a narrow range of temperature and moisture; or, since the dominant floral ecosystem was a highly integrated and complex closed-canopy rainforest by the middle Paleocene, the plant ecosystems were more vulnerable to climate change. There is some evidence that, in the Gulf Coast, there was an extinction event in the late Paleocene preceding the PETM, which may have been due to the aforementioned vulnerability of complex rainforests, and the ecosystem may have been disrupted by only a small change in climate.


title: Paleocene

text: The warm Paleocene climate, much like that of the Cretaceous, allowed for diverse polar forests. Whereas precipitation is a major factor in plant diversity nearer the equator, polar plants had to adapt to varying light availability (polar nights and midnight suns) and temperatures. Because of this, plants from both poles independently evolved some similar characteristics, such as broad leaves. Plant diversity at both poles increased throughout the Paleocene, especially at the end, in tandem with the increasing global temperature.


title: Paleocene

text: At the North Pole, woody angiosperms had become the dominant plants, a reversal from the Cretaceous where herbs proliferated. The Iceberg Bay Formation on Ellesmere Island, Nunavut (latitude 75–80° N) shows remains of a late Paleocene dawn redwood forest, the canopy reaching around , and a climate similar to the Pacific Northwest. On the Alaska North Slope, "Metasequoia" was the dominant conifer. Much of the diversity represented migrants from nearer the equator. Deciduousness was dominant, probably to conserve energy by retroactively shedding leaves and retaining some energy rather than having them die from frostbite.


title: Paleocene

text: At the South Pole, due to the increasing isolation of Antarctica, many plant taxa were endemic to the continent instead of migrating down. Patagonian flora may have originated in Antarctica. The climate was much cooler than in the Late Cretaceous, though frost probably was not common in at least coastal areas. East Antarctica was likely warm and humid. Because of this, evergreen forests could proliferate as, in the absence of frost and a low probability of leaves dying, it was more energy efficient to retain leaves than to regrow them every year. One possibility is that the interior of the continent favored deciduous trees, though prevailing continental climates may have produced winters warm enough to support evergreen forests. As in the Cretaceous, podocarpaceous conifers, "Nothofagus", and Proteaceae angiosperms were common.


title: Paleocene

text: In the K–Pg extinction event, every land animal over was wiped out, leaving open several niches at the beginning of the epoch.


title: Paleocene

text: Mammals had first appeared in the Late Triassic, and remained small and nocturnal throughout the Mesozoic to avoid competition with dinosaurs (nocturnal bottleneck), though, by the Middle Jurassic, they had branched out into several habitats—such as subterranean, arboreal, and aquatic— and the largest known Mesozoic mammal, "Repenomamus robustus" reached about in length and in weight–comparable to the modern day Virginia opossum. Though some mammals could sporadically venture out in daytime (cathemerality) by roughly 10 million years before the K–Pg extinction event, they only became strictly diurnal (active in the daytime) sometime after.


title: Paleocene

text: In general, Paleocene mammals retained this small size until near the end of the epoch, and, consequently, early mammal bones are not well preserved in the fossil record, and most of what is known comes from fossil teeth. Multituberculates, a now-extinct rodent-like group not closely related to any modern mammal, were the most successful group of mammals in the Mesozoic, and they reached peak diversity in the early Paleocene. During this time, multituberculate taxa had a wide range of dental complexity, which correlates to a broader range in diet for the group as a whole. Multituberculates declined in the late Paleocene and went extinct at the end of the Eocene, possibly due to competition from newly evolving rodents.


title: Paleocene

text: Nonetheless, following the K–Pg extinction event, mammals very quickly diversified and filled the empty niches. Modern mammals are subdivided into therians (modern members are placentals and marsupials) and monotremes. These 3 groups all originated in the Cretaceous. Paleocene marsupials include "Peradectes", and monotremes "Monotrematum". The epoch featured the rise of many crown placental groups—groups that have living members in modern day—such as the earliest afrotherian "Ocepeia", xenarthran "Utaetus", rodent "Tribosphenomys" and "Paramys", the forerunners of primates the Plesiadapiformes, earliest carnivorans "Ravenictis" and "Pristinictis", possible pangolins Palaeanodonta, possible forerunners of odd-toed ungulates Phenacodontidae, and eulipotyphlans Nyctitheriidae. Though therian mammals had probably already begun to diversify around 10 to 20 million years before the K–Pg extinction event, average mammal size increased greatly after the boundary, and a radiation into frugivory (fruit-eating) and omnivory began, namely with the newly evolving large herbivores such as the Taeniodonta, Tillodonta, Pantodonta, Polydolopimorphia, and the Dinocerata. Large carnivores include the wolf-like Mesonychia, such as "Ankalagon" and "Sinonyx".


title: Paleocene

text: Though there was an explosive diversification, the affinities of most Paleocene mammals are unknown, and only primates, carnivorans, and rodents have unambiguous Paleocene origins, resulting in a 10 million year gap in the fossil record of other mammalian crown orders. The most species-rich order of Paleocene mammals is Condylarthra, which is a wastebasket taxon for miscellaneous bunodont hoofed mammals. Other ambiguous orders include the Leptictida, Cimolesta, and Creodonta. This uncertainty blurs the early evolution of placentals.


title: Paleocene

text: According to DNA studies, modern birds (Neornithes) rapidly diversified following the extinction of the other dinosaurs in the Paleocene, and nearly all modern bird lineages can trace their origins to this epoch with the exception of fowl and the paleognaths. This was one of the fastest diversifications of any group, probably fueled by the diversification of fruit-bearing trees and associated insects, and the modern bird groups had likely already diverged within 4 million years of the K–Pg extinction event. However, the fossil record of birds in the Paleocene is rather poor compared to other groups, limited globally to mainly waterbirds such as the early penguin "Waimanu". The earliest arboreal crown group bird known is "Tsidiiyazhi", a mousebird dating to around 62 mya. The fossil record also includes early owls such as the large "Berruornis" from France, and the smaller "Ogygoptynx" from the United States.


title: Paleocene

text: Almost all archaic birds (any bird outside Neornithes) went extinct during the K–Pg extinction event, although the archaic "Qinornis" is recorded in the Paleocene. Their extinction may have led to the proliferation of neornithine birds in the Paleocene, and the only known Cretaceous neornithine bird is the waterbird "Vegavis", and possibly also the waterbird "Teviornis".


title: Paleocene

text: In the Mesozoic, birds and pterosaurs exhibited size-related niche partitioning—no known Late Cretaceous flying bird had a wingspan greater than nor exceeded a weight of , whereas contemporary pterosaurs ranged from , probably to avoid competition. Their extinction allowed flying birds to attain greater size, such as pelagornithids and pelecaniformes. The Paleocene pelagornithid "Protodontopteryx" was quite small compared to later members, with a wingspan of about , comparable to a gull. On the archipelago-continent of Europe, the flightless bird "Gastornis" was the largest herbivore at tall for the largest species, possibly due to lack of competition from newly emerging large mammalian herbivores which were prevalent on the other continents. The carnivorous terror birds in South America have a contentious appearance in the Paleocene with "Paleopsilopterus", though the first definitive appearance is in the Eocene.


title: Paleocene

text: It is generally believed all non-avian dinosaurs went extinct at the K–Pg extinction event 66 mya, though there are a couple of controversial claims of Paleocene dinosaurs which would indicate a gradual decline of dinosaurs. Contentious dates include remains from the Hell Creek Formation dated 40,000 years after the boundary, and a hadrosaur femur from the San Juan Basin dated to 64.5 mya, but such stray late forms may be zombie taxa that were washed out and moved to younger sediments.


title: Paleocene

text: In the wake of the K–Pg extinction event, 83% of lizard and snake (squamate) species went extinct, and the diversity did not fully recover until the end of the Paleocene. However, since the only major squamate lineages to disappear in the event were the mosasaurs and polyglyphanodontians (the latter making up 40% of Maastrichtian lizard diversity), and most major squamate groups had evolved by the Cretaceous, the event probably did not greatly affect squamate evolution, and newly evolving squamates did not seemingly branch out into new niches as mammals. That is, Cretaceous and Paleogene squamates filled the same niches. Nonetheless, there was a faunal turnover of squamates, and groups that were dominant by the Eocene were not as abundant in the Cretaceous, namely the anguids, iguanas, night lizards, pythons, colubrids, boas, and worm lizards. Only small squamates are known from the early Paleocene—the largest snake "Helagras" was in length—but the late Paleocene snake "Titanoboa" grew to over long, the longest snake ever recorded. "Kawasphenodon peligrensis" from the early Paleocene of South America represents the youngest record of Rhynchocephalia outside of New Zealand, where the only extant representative of the order, the tuatara, resides.


title: Paleocene

text: Freshwater crocodilians and choristoderans were among the aquatic reptiles to have survived the K–Pg extinction event, probably because freshwater environments were not as impacted as marine ones. One example of a Paleocene crocodile is "Borealosuchus", which averaged in length at the Wannagan Creek site. Among crocodyliformes, the aquatic and terrestrial dyrosaurs and the fully terrestrial sebecids would also survive the K-Pg extinction event, and a late surviving member of Pholidosauridae is also known from the Danian of Morocco. Three choristoderans are known from the Paleocene: The gharial-like neochoristoderans "Champsosaurus"—the largest is the Paleocene "C. gigas" at ", Simoedosaurus"—the largest specimen measuring , and an indeterminate species of the lizard like non-neochoristoderan "Lazarussuchus" around 44 centimetres in length. The last known choristoderes, belonging to the genus "Lazarussuchus," are known from the Miocene.


title: Paleocene

text: Turtles experienced a decline in the Campanian (Late Cretaceous) during a cooling event, and recovered during the PETM at the end of the Paleocene. Turtles were not greatly affected by the K–Pg extinction event, and around 80% of species survived. In Colombia, a 60 million year old turtle with a carapace, "Carbonemys", was discovered.


title: Paleocene

text: There is little evidence amphibians were affected very much by the K–Pg extinction event, probably because the freshwater habitats they inhabited were not as greatly impacted as marine environments. In the Hell Creek Formation of eastern Montana, a 1990 study found no extinction in amphibian species across the boundary. The true toads evolved during the Paleocene. The final record of albanerpetontids from North America and outside of Europe and Anatolia, an unnamed species of "Albanerpeton", is known from the Paleocene aged Paskapoo Formation in Canada.


title: Paleocene

text: The small pelagic fish population recovered rather quickly, and there was a low extinction rate for sharks and rays. Overall, only 12% of fish species went extinct. During the Cretaceous, fishes were not very abundant, probably due to heightened predation by or competition with ammonites and squid, although large predatory fish did exist, including ichthyodectids, pachycormids, and pachyrhizodontids. Almost immediately following the K–Pg extinction event, ray-finned fish—today, representing nearly half of all vertebrate taxa—became much more numerous and increased in size, and rose to dominate the open-oceans. Acanthomorphs—a group of ray-finned fish which, today, represent a third of all vertebrate life—experienced a massive diversification following the K–Pg extinction event, dominating marine ecosystems by the end of the Paleocene, refilling vacant, open-ocean predatory niches as well as spreading out into recovering reef systems. In specific, percomorphs diversified faster than any other vertebrate group at the time, with the exception of birds; Cretaceous percomorphs varied very little in body plan, whereas, by the Eocene, percomorphs evolved into vastly varying creatures such as early scombrids (today, tuna, mackerels, and bonitos), barracudas, jacks, billfish, flatfishes, and aulostomoid (trumpetfish and cornetfish). However, the discovery of the Cretaceous cusk eel "Pastorius" shows that the body plans of at least some percomorphs were already highly variable, perhaps indicating an already diverse array of percomorph body plans before the Paleocene.


title: Paleocene

text: Conversely, sharks and rays appear to have been unable to exploit the vacant niches, and recovered the same pre-extinction abundance. There was a faunal turnover of sharks from mackerel sharks to ground sharks, as ground sharks are more suited to hunting the rapidly diversifying ray-finned fish whereas mackerel sharks target larger prey. The first megatoothed shark, "Otodus obliquus"—the ancestor of the giant megalodon—is recorded from the Paleocene.


title: Paleocene

text: Several Paleocene freshwater fish are recorded from North America, including bowfins, gars, arowanas, Gonorynchidae, common catfish, smelts, and pike.


title: Paleocene

text: Insect recovery varied from place to place. For example, it may have taken until the PETM for insect diversity to recover in the western interior of North America, whereas Patagonian insect diversity had recovered by 4 million years after the K–Pg extinction event. In some areas, such as the Bighorn Basin in Wyoming, there is a dramatic increase in plant predation during the PETM, although this is probably not indicative of a diversification event in insects due to rising temperatures because plant predation decreases following the PETM. More likely, insects followed their host plant or plants which were expanding into mid-latitude regions during the PETM, and then retreated afterward.


title: Paleocene

text: The middle-to-late Paleocene French Menat Formation shows an abundance of beetles (making up 77.5% of the insect diversity)—especially weevils (50% of diversity), jewel beetles, leaf beetles, and reticulated beetles—as well as other true bugs—such as pond skaters—and cockroaches. To a lesser degree, there are also orthopterans, hymenopterans, butterflies, and flies, though planthoppers were more common than flies. Representing less than 1% of fossil remains dragonflies, caddisflies, mayflies, earwigs, mantises, net-winged insects, and possibly termites.


title: Paleocene

text: The Wyoming Hanna Formation is the only known Paleocene formation to produce sizable pieces of amber, as opposed to only small droplets. The amber was formed by a single or a closely related group of either taxodiaceaen or pine tree(s) which produced cones similar to those of dammaras. Only one insect, a thrips, has been identified.


title: Paleocene

text: There is a gap in the ant fossil record from 78 to 55 mya, except for the aneuretine "Napakimyrma paskapooensis" from the 62–56 million year old Canadian Paskapoo Formation. Given high abundance in the Eocene, two of the modern dominant ant subfamilies—Ponerinae and Myrmicinae—likely originated and greatly diversified in the Paleocene, acting as major hunters of arthropods, and probably competed with each other for food and nesting grounds in the dense angiosperm leaf litter. Myrmicines expanded their diets to seeds and formed trophobiotic symbiotic relationships with aphids, mealybugs, treehoppers, and other honeydew secreting insects which were also successful in angiosperm forests, allowing them to invade other biomes, such as the canopy or temperate environments, and achieve a worldwide distribution by the middle Eocene.


title: Paleocene

text: About 80% of the butterfly and moth (lepidopteran) fossil record occurs in the early Paleogene, specifically the late Paleocene and the middle-to-late Eocene. Most Paleocene lepidopteran compression fossils come from the Danish Fur Formation. Though there is low family-level diversity in the Paleocene compared to later epochs, this may be due to a largely incomplete fossil record. The evolution of bats had a profound effect on lepidopterans, which feature several anti-predator adaptations such as echolocation jamming and the ability to detect bat signals.


title: Paleocene

text: Bees were likely heavily impacted by the K–Pg extinction event and a die-off of flowering plants, though the bee fossil record is very limited. The oldest kleptoparasitic bee, "Paleoepeolus", is known from the Paleocene 60 mya.


title: Paleocene

text: Though the Eocene features, by far, the highest proportion of known fossil spider species, the Paleocene spider assemblage is quite low. Some spider groups began to diversify around the PETM, such as jumping spiders, and possibly coelotine spiders (members of the funnel weaver family).


title: Paleocene

text: The diversification of mammals had a profound effect on parasitic insects, namely the evolution of bats, which have more ectoparasites than any other known mammal or bird. The PETM's effect on mammals greatly impacted the evolution of fleas, ticks, and oestroids.


title: Paleocene

text: Among marine invertebrates, plankton and those with a planktonic stage in their development (meroplankton) were most impacted by the K–Pg extinction event, and plankton populations crashed. Nearly 90% of all calcifying plankton species perished. This reverberated up and caused a global marine food chain collapse, namely with the extinction of ammonites and large raptorial marine reptiles. Nonetheless, the rapid diversification of large fish species indicates a healthy plankton population through the Paleocene.


title: Paleocene

text: Marine invertebrate diversity may have taken about 7 million years to recover, though this may be a preservation artifact as anything smaller than is unlikely to be fossilized, and body size may have simply decreased across the boundary. A 2019 study found that in Seymour Island, Antarctica, the marine life assemblage consisted primarily of burrowing creatures—such as burrowing clams and snails—for around 320,000 years after the K–Pg extinction event, and it took around a million years for the marine diversity to return to previous levels. Areas closer to the equator may have been more affected. Sand dollars first evolved in the late Paleocene. The Late Cretaceous decapod crustacean assemblage of James Ross Island appears to have been mainly pioneer species and the ancestors of modern fauna, such as the first Antarctic crabs and the first appearance of the lobsters of the genera "Linuparus", "Metanephrops", and "Munidopsis" which still inhabit Antarctica today.


title: Paleocene

text: In the Cretaceous, the main reef-building creatures were the box-like bivalve rudists instead of coral—though a diverse Cretaceous coral assemblage did exist—and rudists had collapsed by the time of the K–Pg extinction event. Some corals are known to have survived in higher latitudes in the Late Cretaceous and into the Paleogene, and hard coral-dominated reefs may have recovered by 8 million years after the K–Pg extinction event, though the coral fossil record of this time is rather sparse. Though there was a lack of extensive coral reefs in the Paleocene, there were some colonies—mainly dominated by zooxanthellate corals—in shallow coastal (neritic) areas. Starting in the latest Cretaceous and continuing until the early Eocene, calcareous corals rapidly diversified. Corals probably competed mainly with red and coralline algae for space on the seafloor. Calcified dasycladalean green algae experienced the greatest diversity in their evolutionary history in the Paleocene. Though coral reef ecosystems do not become particularly abundant in the fossil record until the Miocene (possibly due to preservation bias), strong Paleocene coral reefs have been identified in what are now the Pyrenees (emerging as early as 63 mya), with some smaller Paleocene coral reefs identified across the Mediterranean region.


title: Hypernatremia

text: Hypernatremia, also spelled hypernatraemia, is a high concentration of sodium in the blood. Early symptoms may include a strong feeling of thirst, weakness, nausea, and loss of appetite. Severe symptoms include confusion, muscle twitching, and bleeding in or around the brain. Normal serum sodium levels are 135–145 mmol/L (135–145 mEq/L). Hypernatremia is generally defined as a serum sodium level of more than 145 mmol/L. Severe symptoms typically only occur when levels are above 160 mmol/L.


title: Hypernatremia

text: Hypernatremia is typically classified by a person's fluid status into low volume, normal volume, and high volume. Low volume hypernatremia can occur from sweating, vomiting, diarrhea, diuretic medication, or kidney disease. Normal volume hypernatremia can be due to fever, extreme thirst, prolonged increased breath rate, diabetes insipidus, and from lithium among other causes. High volume hypernatremia can be due to hyperaldosteronism, excessive administration of intravenous 3% normal saline or sodium bicarbonate, or rarely from eating too much salt. Low blood protein levels can result in a falsely high sodium measurement. The cause can usually be determined by the history of events. Testing the urine can help if the cause is unclear. The underlying mechanism typically involves too little free water in the body.


title: Hypernatremia

text: If the onset of hypernatremia was over a few hours, then it can be corrected relatively quickly using intravenous normal saline and 5% dextrose in water. Otherwise, correction should occur slowly with, for those unable to drink water, half-normal saline. Hypernatremia due to diabetes insipidus as a result of a brain disorder, may be treated with the medication desmopressin. If the diabetes insipidus is due to kidney problems the medication causing the problem may need to be stopped or the underlying electrolyte disturbance corrected. Hypernatremia affects 0.3–1% of people in hospital. It most often occurs in babies, those with impaired mental status, and the elderly. Hypernatremia is associated with an increased risk of death but it is unclear if it is the cause.


title: Hypernatremia

text: The major symptom is thirst. The most important signs result from brain cell shrinkage and include confusion, muscle twitching or spasms. With severe elevations, seizures and comas may occur.


title: Hypernatremia

text: Severe symptoms are usually due to acute elevation of the plasma sodium concentration to above 157 mmol/L (normal blood levels are generally about 135–145 mmol/L for adults and elderly). Values above 180 mmol/L are associated with a high mortality rate, particularly in adults. However, such high levels of sodium rarely occur without severe coexisting medical conditions. Serum sodium concentrations have ranged from 150 to 228 mmol/L in survivors of acute salt overdosage, while levels of 153–255 mmol/L have been observed in fatalities. Vitreous humor is considered to be a better postmortem specimen than postmortem serum for assessing sodium involvement in a death.


title: Hypernatremia

text: Hypernatremia is diagnosed when a basic metabolic panel blood test demonstrates a sodium concentration higher than 145 mmol/L.


title: Hypernatremia

text: The cornerstone of treatment is administration of free water to correct the relative water deficit. Water can be replaced orally or intravenously. Water alone cannot be administered intravenously (because of osmolarity issues leading to rupturing of red blood cells in the bloodstream), but rather can be given intravenously in solution with dextrose (sugar) or saline (salt). However, overly rapid correction of hypernatremia is potentially very dangerous. The body (in particular the brain) adapts to the higher sodium concentration. Rapidly lowering the sodium concentration with free water, once this adaptation has occurred, causes water to flow into brain cells and causes them to swell. This can lead to cerebral edema, potentially resulting in seizures, permanent brain damage, or death. Therefore, significant hypernatremia should be treated carefully by a physician or other medical professional with experience in treatment of electrolyte imbalance. Specific treatments such as thiazide diuretics (e.g., chlorthalidone) in congestive heart failure or corticosteroids in nephropathy also can be used.


title: Mrinal Kulkarni

text: Mrinal Deo-Kulkarni (born 21 June 1971) is a senior film, TV actress and director of India. She is better known for her role as Meerabai in doordarshan's Meerabai seriel and angel in Hindi TV serial "Son Pari". She has acted in Marathi language and Hindi TV serials and films.


title: Mrinal Kulkarni

text: She was born in a Marathi Deshastha Brahmin family in Pune. Her parents are Dr. Vijay Deo and Veena Deo. She has a Master's degree in Linguistics from Pune University. She has a sister named Madhura. She lost her father after illness on 11 April 2019.


title: Mrinal Kulkarni

text: She married her childhood friend Ruchir Kulkarni in 1990 and has a son Virajas who is also a part of Marathi film industry.


title: Mrinal Kulkarni

text: Mrinal was 16 when she made her debut in the role of Peshawe Madhavrao's wife, Ramabai Peshawe, in the Marathi TV serial "Swami". This gave her a popularity. Ravindra Mankani played the role of Madhavrao.