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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Gremlin (Programming Language)
Gremlin is a graph traversal language and virtual machine developed by Apache TinkerPop of the Apache Software Foundation. Gremlin works for both OLTP-based graph databases as well as OLAP-based graph processors. Gremlin's automata and functional language foundation enable Gremlin to naturally support imperative and declarative querying, host language agnosticism, user-defined domain specific languages, an extensible compiler/optimizer, single- and multi-machine execution models, hybrid depth- and breadth-first evaluation, as well as Turing Completeness. As an explanatory analogy, Apache TinkerPop and Gremlin are to graph databases what the JDBC and SQL are to relational databases. Likewise, the Gremlin traversal machine is to graph computing as what the Java virtual machine is to general purpose computing.
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  • 10 Oct 2022
Topic Review
Intergeneric Hybrid
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled. Human impact on the environment has resulted in an increase in the interbreeding between regional species, and the proliferation of introduced species worldwide has also resulted in an increase in hybridisation. This genetic mixing may threaten many species with extinction, while genetic erosion from monoculture in crop plants may be damaging the gene pools of many species for future breeding. A form of often intentional human-mediated hybridisation is the crossing of wild and domesticated species. This is common in both traditional horticulture and modern agriculture; many commercially useful fruits, flowers, garden herbs, and trees have been produced by hybridisation. One such flower, Oenothera lamarckiana, was central to early genetics research into mutationism and polyploidy. It is also more occasionally done in the livestock and pet trades; some well-known wild × domestic hybrids are beefalo and wolfdogs. Human selective breeding of domesticated animals and plants has resulted in the development of distinct breeds (usually called cultivars in reference to plants); crossbreeds between them (without any wild stock) are sometimes also imprecisely referred to as "hybrids". Hybrid humans existed in prehistory. For example, Neanderthals and anatomically modern humans are thought to have interbred as recently as 40,000 years ago. Mythological hybrids appear in human culture in forms as diverse as the Minotaur, blends of animals, humans and mythical beasts such as centaurs and sphinxes, and the Nephilim of the Biblical apocrypha described as the wicked sons of fallen angels and attractive women.
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  • 10 Oct 2022
Topic Review
List of Unnumbered Minor Planets: 2004 R–S
This is a partial list of unnumbered minor planets for principal designations assigned between 1 September 2004 and 31 September 2004 (R–S).
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  • 10 Oct 2022
Topic Review
Partition Problem
In number theory and computer science, the partition problem, or number partitioning, is the task of deciding whether a given multiset S of positive integers can be partitioned into two subsets S1 and S2 such that the sum of the numbers in S1 equals the sum of the numbers in S2. Although the partition problem is NP-complete, there is a pseudo-polynomial time dynamic programming solution, and there are heuristics that solve the problem in many instances, either optimally or approximately. For this reason, it has been called "the easiest hard problem". There is an optimization version of the partition problem, which is to partition the multiset S into two subsets S1, S2 such that the difference between the sum of elements in S1 and the sum of elements in S2 is minimized. The optimization version is NP-hard, but can be solved efficiently in practice.
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  • 10 Oct 2022
Topic Review
Sex Differences in Memory
Although there are many physiological and psychological gender differences in humans, memory, in general, is fairly stable across the sexes. By studying the specific instances in which males and females demonstrate differences in memory, we are able to further understand the brain structures and functions associated with memory. It is within specific experimental trials that differences appear, such as methods of recalling past events, explicit facial emotion recognition tasks, and neuroimaging studies regarding size and activation of different brain regions. Research seems to focus especially on gender differences in explicit memory. Like many other nuances of the human psyche, these differences are studied with the goal of lending insight to a greater understanding of the human brain.
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  • 10 Oct 2022
Topic Review
Cascading Style Sheets
Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language like HTML. CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript. CSS is designed to enable the separation of presentation and content, including layout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple web pages to share formatting by specifying the relevant CSS in a separate .css file, and reduce complexity and repetition in the structural content. Separation of formatting and content also makes it feasible to present the same markup page in different styles for different rendering methods, such as on-screen, in print, by voice (via speech-based browser or screen reader), and on Braille-based tactile devices. CSS also has rules for alternate formatting if the content is accessed on a mobile device. The name cascading comes from the specified priority scheme to determine which style rule applies if more than one rule matches a particular element. This cascading priority scheme is predictable. The CSS specifications are maintained by the World Wide Web Consortium (W3C). Internet media type (MIME type) text/css is registered for use with CSS by RFC 2318 (March 1998). The W3C operates a free CSS validation service for CSS documents. In addition to HTML, other markup languages support the use of CSS including XHTML, plain XML, SVG, and XUL.
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  • 10 Oct 2022
Topic Review
Plug-in Electric Vehicles in Germany
The adoption of plug-in electric vehicles in Germany is actively supported by the German Federal Government. Under its National Plattform for Electric Mobility, Chancellor Angela Merkel set an initial goal in 2010 to deploy one million electric vehicles on German roads by 2020. Initially, the government did not provide subsidies to promote sales of plug-in electric vehicles, however, by the end of 2014 it was recognized that the country was well behind the set sales targets. A purchase bonus scheme was approved in 2016, but premium cars were not eligible to the incentive. In order to meet the climate targets for the transport sector, in 2016 the government set the goal to have from 7 to 10 million plug-in electric cars on the road by 2030, and 1 million charging points deployed by 2030. In June 2020, and as a result of the economic impact of the COVID-19 pandemic, the government approved a recovery plan which included €8 billion to promote electric vehicle adoption and deployment of charging infrastructure. The purchase bonus for all-electric cars was raised temporarily from €6,000 to €9,000 for cars costing less than €40,000. There are lower bonuses for the purchase of plug-in hybrids, used cars and for leasing. The additional bonus will be available until the end of 2025. The initial one million goal was achieved in July 2021. The stock of plug-in electric vehicles in Germany is the largest in Europe, and (As of July 2021), there were 1 million plug-in electric vehicles on the road, including buses and commercial vehicles. The German fleet in use consists of 54% all-electric vehicles and 46% plug-in hybrids. (As of December 2019), Germany had a stock of 21,890 light-duty electric commercial vehicles, the second largest in Europe after France. (As of March 2020), the country had 27,730 public charging stations. The plug-in electric car segment market share was 1.58% in 2017 and 1.9% in 2018. The segment market share rose to 3.10% in 2019, and despite the global strong decline in car sales brought by the COVID-19 pandemic, the uptake rate achieved a record 13.6% in 2020. (As of January 2021), the stock of German plug-in electric cars on the road totaled 588,944 units, representing 1.2% of all registered passenger cars, up from 0.5% the previous year. In 2019, Germany surpassed Norway as Europe's top selling country market in terms of annual sales, and with a record volume of 394,632 plug-in passenger cars registered in 2020, up 263% from 2019, Germany listed for a second year running as the best selling European plug-in market. Both years, the German market led both the fully electric and plug-in hybrid segments. The only country that outsold Germany in 2020 was China.
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  • 10 Oct 2022
Topic Review
Services for Mental Disorders
Services for mental health disorders provide treatment, support, or advocacy to people who have psychiatric illnesses. These may include medical, behavioral, social, and legal services. Medical services are usually provided by mental health experts like psychiatrists, psychologists, and behavioral health counselors in a hospital or outpatient clinic. Behavioral services go hand-in-hand with medical services, referring specifically to pharmacological and cognitive therapy. Social services are usually provided by the government or nonprofit organizations. They arrange housing options, job training, or other community resources overseen by experienced professionals to ensure overall productivity and well being of individuals with mental illnesses. Legal services ensure that people with mental health disorders are not discriminated against in society and advocate for their basic human rights. In addition, legal services make sure that those individuals who might be a danger to themselves or others are diverted away from the judicial system to receive adequate treatment for underlying mental health issues. The information provided below is primarily regarding services offered within the United States of America, unless otherwise specified.
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  • 10 Oct 2022
Topic Review
London School of Economics Gaddafi Links
The affair of the LSE Libya Links refers to the various connections that existed between the London School of Economics and Political Science (LSE) and the Libyan government and its leader Muammar Gaddafi and his son Saif al-Islam Gaddafi. The NGO Gaddafi Foundation pledged to donate £1.5 million over five years to a research centre, LSE Global Governance, of which £300k were paid. In addition, LSE Enterprise established a contract worth £2.2 million to train Libyan officials. In 2008, the LSE granted a PhD degree to Saif al-Islam Gaddafi, the son of the Libyan leader, for a dissertation. Currently, allegations circulate that Gaddafi's thesis was ghost-written and/or plagiarised. In December 2010, Muammar Gaddafi addressed members of the School in a video link-up where he was addressed as "Brother Leader" and received an LSE cap previously given to Nelson Mandela. In connection with the civil uprising in Libya in February and March 2011, the links between LSE and the Gaddafi regime, and the conduct of individual members of LSE's staff, came increasingly to be questioned. As a result of the revelations, the LSE's Director, Sir Howard Davies, resigned on 3 March 2011, citing "errors of judgement". In a New York Times op-ed piece on 7 March 2011, Roger Cohen wrote, in reference to events that had transpired at the School, "It may be possible to sink to greater depths but right now I can't think how. ...The Arab Spring is also a Western Winter. ...How did we back, use and encourage the brutality of Arab dictators over so many years? To what degree did that cynical encouragement of despots foster the very jihadist rage Western societies sought to curb?"
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  • 10 Oct 2022
Topic Review
Snorkeling
Snorkeling (British and Commonwealth English spelling: snorkelling) is the practice of swimming on or through a body of water while equipped with a diving mask, a shaped breathing tube called a snorkel, and usually swimfins. In cooler waters, a wetsuit may also be worn. Use of this equipment allows the snorkeler to observe underwater attractions for extended periods with relatively little effort and to breathe while face-down at the surface. Snorkeling is a popular recreational activity, particularly at tropical resort locations. The primary appeal is the opportunity to observe underwater life in a natural setting without the complicated equipment and training required for scuba diving. It appeals to all ages because of how little effort there is, and without the exhaled bubbles of scuba-diving equipment. It is the basis of the two surface disciplines of the underwater sport of finswimming. Snorkeling is also used by scuba divers when on the surface, in underwater sports such as underwater hockey and underwater rugby, and as part of water-based searches conducted by search and rescue teams.
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  • 10 Oct 2022
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