Rationale for XML in databases.

There are a number of reasons to directly specify data in XML or other document formats such as JSON. For XML in particular, they include:  Steve O'Connell gives one reason for the use of XML in databases: the increasingly common use of XML for data transport, which has meant that "data is extracted from databases and put into XML documents and vice-versa". It may prove more efficient (in terms of conversion costs) and easier to store the data in XML format. In content-based applications, the ability of the native XML database also minimizes the need for extraction or entry of metadata to support searching and navigation.

XML enabled databases.

XML enabled databases typically offer one or more of the following approaches to storing XML within the traditional relational structure:  RDBMS that support the ISO XML Type are:  Typically an XML enabled database is best suited where the majority of data are non-XML. For datasets where the majority of data are XML, a native XML database is better suited.

Example of XML Type Query in IBM DB2 SQL.

select from where

Native XML databases.

Native XML databases are especially tailored for working with XML data. As managing XML as large strings would be inefficient, and due to the hierarchical nature of XML, custom optimized data structures are used for storage and querying. This usually increases performance both in terms of read-only queries and updates. XML nodes and documents are the fundamental unit of (logical) storage, just as a relational database has fields and rows.  The standard for querying XML data per W3C recommendation is XQuery; the latest version is XQuery 3.1. XQuery includes XPath as a sub-language and XML itself is a valid sub-syntax of XQuery. In contrast to XML enabled databases, native databases provide full support for XQuery. In addition to XPath, some XML databases support XSLT as a method of transforming documents or query results retrieved from the database.

Data-centric XML datasets.

For data-centric XML datasets, the unique and distinct keyword search method, namely, XDMA for XML databases is designed and developed based on dual indexing and mutual summation.

An XML database is a data persistence software system that allows data to be specified, and sometimes stored, in XML format. This data can be queried, transformed, exported and returned to a calling system. XML databases are a flavor of document-oriented databases which are in turn a category of NoSQL database.

Der Begriff XML-Datenbank charakterisiert die Eigenschaft einer Datenbank oder eines Datenbankverwaltungssystems, mit XML ausgezeichnete Dokumente speichern und durchsuchen zu können.


Shihan.

Within the JAA there were two Shihan: Tetsuro Nariyama and Fumiaki Shishida. Nariyama as the technical director of the JAA and chief instructor of the Shodokan hombu dojo in Osaka, Japan. Shishida is Professor of Intellectual History of the Japanese Martial Arts at Waseda University in Tokyo. Together, they wrote a key monograph, in Japanese, entitled "Aikido Kyougi", which describes the history of, and many technical details about, the style of aikido propounded by Tomiki. This book, first published in 1985, was subsequently translated into English under the title, "Aikido: Tradition and the Competitive Edge". Nariyama Shihan has also produced a further book, "Aikido Randori", describing the practice system of randori within aikido.  In recent years, Sato Tadayuki was made Shihan of Waseda University Aikido Club. He, along with the now late Kenshi Uno, of Shikoku Japan, created Shidokan, with the blessing of Shishida Shihan. This system follows the same teachings of Tomiki, but with different emphasis, a return to Tomiki's earliest methods. Tomiki gave his art the name Shodokan, and many people were concerned with the introduction of a new name Shidokan. However this is just to show the various paths available within Tomiki's aikido.  As of 2012, the division between Nariyama Shihan and Shishida Shihan grew into a situation where the two of them remaining within a single organization became an untenable position. Thus Nariyama Shihan decided to resolve any conflict by resigning from the JAA and creating a new organization known as Shodokan Aikido Renmei (also known as Shodokan Aikido Federation). This effectively was an official split of the Shodokan Aikido world into two. The JAA now refer to Shodokan Aikido as "Tomiki Aikido". However, because Tomiki Shihan emphatically was against the use of his name being attached to his system of practice, the JAA also commonly refers to the system as "The Aikido of Kenji Tomiki Sensei".

Kata.

Shodokan defines several kata. Some of the more important kata are listed below.

Junanahon.

Randori no kata is the basic kata set for Shodokan Aikido. Junanahon consists of 17 basic techniques, which, with their variations, are legal within Shodokan randori. They are broken down into four different categories: Atemi, Hiji, Tekubi and Uki. Kenji Tomiki thought for many years about the construction of the 17 techniques as he omitted techniques from the old styles that he deemed too complex or too dangerous for competition.

Atemi Waza.

The Atemi Waza is a set of five techniques that are classified as striking techniques.

Hiji Waza.

The Hiji Waza is a set of five techniques that are classified as elbow techniques.

Tekubi Waza.

The Tekubi Waza is a set of four techniques that are classified as wrist techniques.

Uki Waza.

The Uki Waza is a set of three techniques that are classified as floating techniques.

Koryu Goshin no Kata.

"Old stream self defense kata," includes many techniques that harken back to pre-war aikido (when the art was still taught as Daito-ryu aiki-jujutsu). This set of 50 techniques is sometimes referred to as the "Koryu dai san" and includes weapons as well as empty-hand techniques. Suwari Waza: 4 techniques Hanza Handachi: 4 techniques Tachi Waza: 8 techniques Tanto dori: 8 techniques Tachi dori: 5 techniques Yari dori: 5 techniques Yari wo kumitsukareta: 8 techniques Kumi Tachi: 8 techniques

Nage no kata.

A set of 14 throwing techniques: 7 direct (omote) and 7 more circular and fluid (ura). This sequence is actually the first part of "Koryu dai yon" which includes 11 more techniques.

Goshin Ho.

Self-defense techniques several of which are part of the curriculum for yondan and up.

Competition.

Competitions take the form of "tanto randori" or "toshu randori", and also "embu" (演武) in which pairs (tori and uke) are judged on their kata. "Toshu randori" (徒手乱取) is barehanded, and both practitioners are expected to perform techniques on one another and attempt to resist and counter each other's techniques. The appearance of this form is heavily influenced by judo randori with a few changes designed to enhance the use of aikido technique (for example, one is not allowed to grasp the opponent's keikogi).  In "tanto randori" (短刀乱取), there is a designated attacker ("tantō") and a designated empty-handed defender ("toshu"). The attacker attempts to stab the defender with a training knife (usually rubber or stuffed) while the defender attempts, with any of seventeen basic aikido techniques, to throw or perform joint-locks on the attacker. "Tantō" is expected to resist or counter with the first five techniques. In competition, the roles switch, with competitors having the same amount of time with and without the knife. In both these forms of "randori", the traditional separation between the performer of technique ("tori") and the receiver of technique ("uke") no longer exists, as either participant may throw the opponent.

World Championships.

The Aikido World Championships are held every two years, rotating between Japan and a foreign location.

International Instruction.

Instructors from Shodokan Hombu regularly teach internationally. Currently the main traveling instructors are Tetsuro Nariyama (9th Dan), Omori Ryuichi (7th Dan), Endo Sekio (6th Dan) and Sakai Shinnosuke (6th Dan).

In 1967 Kenji Tomiki built a Shodokan hombu dojo in Osaka, Japan, to teach, train and promote his style. The style itself, could arguably have been founded with the formation of the Waseda University Aikido Club in 1958, although Tomiki didn't actually name his style Shodokan until 1976. Today, Shodokan Aikido is organised with two major groups, the Japan Aikido Association "(JAA)" and the Shodokan Aikido Federation "(SAF)".

Shodokan (jap. 昭道館 Shōdōkan) ist eine Stilrichtung der japanischen Kampfkunst Aikidō, die von Tomiki Kenji (1900–1979) entwickelt wurde. Tomiki war ein Schüler von Kanō Jigorō, Gründer des Kōdōkan (Jūdō)-Judo, und Ueshiba Morihei, Gründer des Aikidō. Shodokan-Aikidō vereinigt die Techniken des traditionellen Aikidō mit der modernen Didaktik und Struktur, die Kanō Jigorō zur Lehre des Judo einsetzt. Das Resultat ist ein modernes, wirksames und strukturiertes Aikidō, das heute in Japan und in vielen Ländern weltweit unterrichtet wird.


Professional.

Professional peer review focuses on the performance of professionals, with a view to improving quality, upholding standards, or providing certification. In academia, peer review is used to inform in decisions related to faculty advancement and tenure. Henry Oldenburg (1619–1677) was a German-born British philosopher who is seen as the 'father' of modern scientific peer review.  WA prototype is a professional peer-review process originally recommended in the "Ethics of the Physician" written by Ishāq ibn ʻAlī al-Ruhāwī (854–931). He stated that a visiting physician had to make duplicate notes of a patient's condition on every visit. When the patient was cured or had died, the notes of the physician were examined by a local medical council of other physicians, who would decide whether the treatment had met the required standards of medical care.  Professional peer review is common in the field of health care, where it is usually called "clinical peer review". Further, since peer review activity is commonly segmented by clinical discipline, there is also physician peer review, nursing peer review, dentistry peer review, etc. Many other professional fields have some level of peer review process: accounting, law, engineering (e.g., software peer review, technical peer review), aviation, and even forest fire management.  Peer review is used in education to achieve certain learning objectives, particularly as a tool to reach higher order processes in the affective and cognitive domains as defined by Bloom's taxonomy. This may take a variety of forms, including closely mimicking the scholarly peer review processes used in science and medicine.

Government policy.

The European Union has been using peer review in the "Open Method of Co-ordination" of policies in the fields of active labour market policy since 1999. In 2004, a program of peer reviews started in social inclusion. Each program sponsors about eight peer review meetings in each year, in which a "host country" lays a given policy or initiative open to examination by half a dozen other countries and the relevant European-level NGOs. These usually meet over two days and include visits to local sites where the policy can be seen in operation. The meeting is preceded by the compilation of an expert report on which participating "peer countries" submit comments. The results are published on the web.  The United Nations Economic Commission for Europe, through UNECE Environmental Performance Reviews, uses peer review, referred to as "peer learning", to evaluate progress made by its member countries in improving their environmental policies.  The State of California is the only U.S. state to mandate scientific peer review. In 1997, the Governor of California signed into law Senate Bill 1320 (Sher), Chapter 295, statutes of 1997, which mandates that, before any CalEPA Board, Department, or Office adopts a final version of a rule-making, the scientific findings, conclusions, and assumptions on which the proposed rule are based must be submitted for independent external scientific peer review. This requirement is incorporated into the California Health and Safety Code Section 57004.

Medical.

Medical peer review may be distinguished in 4 classifications: 1) clinical peer review; 2) peer evaluation of clinical teaching skills for both physicians and nurses; 3) scientific peer review of journal articles; 4) a secondary round of peer review for the clinical value of articles concurrently published in medical journals. Additionally, "medical peer review" has been used by the American Medical Association to refer not only to the process of improving quality and safety in health care organizations, but also to the process of rating clinical behavior or compliance with professional society membership standards. Thus, the terminology has poor standardization and specificity, particularly as a database search term.

Technical.

In engineering, technical peer review is a type of engineering review. Technical peer reviews are a well defined review process for finding and fixing defects, conducted by a team of peers with assigned roles. Technical peer reviews are carried out by peers representing areas of life cycle affected by material being reviewed (usually limited to 6 or fewer people). Technical peer reviews are held within development phases, between milestone reviews, on completed products or completed portions of products.

Criticism.

To an outsider, the anonymous, pre-publication peer review process is opaque. Certain journals are accused of not carrying out stringent peer review in order to more easily expand their customer base, particularly in journals where authors pay a fee before publication. Richard Smith, MD, former editor of the "British Medical Journal", has claimed that peer review is "ineffective, largely a lottery, anti-innovatory, slow, expensive, wasteful of scientific time, inefficient, easily abused, prone to bias, unable to detect fraud and irrelevant; Several studies have shown that peer review is biased against the provincial and those from low- and middle-income countries; Many journals take months and even years to publish and the process wastes researchers' time. As for the cost, the Research Information Network estimated the global cost of peer review at £1.9 billion in 2008."  In addition, Australia's Innovative Research Universities group (a coalition of seven comprehensive universities committed to inclusive excellence in teaching, learning and research in Australia) has found that "peer review disadvantages researchers in their early careers, when they rely on competitive grants to cover their salaries, and when unsuccessful funding applications often mark the end of a research idea".

Low-end distinctions in articles understandable to all peers.

John Ioannidis argues that since the exams and other tests that people pass on their way from "layman" to "expert" focus on answering the questions in time and in accordance with a list of answers, and not on making precise distinctions (the latter of which would be unrecognizable to experts of lower cognitive precision anyway), there is as much individual variation in the ability to distinguish causation from correlation among "experts" as there is among "laymen". Ioannidis argues that as a result, scholarly peer review by many "experts" allows only articles that are understandable at a wide range of cognitive precision levels including very low ones to pass, biasing publications towards favoring articles that infer causation from correlation while mislabelling articles that make the distinction as "incompetent overestimation of one's ability" on the side of the authors because some of the reviewing "experts" are cognitively unable to distinguish the distinction from alleged rationalization of specific conclusions. It is argued by Ioannidis that this makes peer review a cause of selective publication of false research findings while stopping publication of rigorous criticism thereof, and that further postpublication review repeats the same bias by selectively retracting the few rigorous articles that may have made it through initial prepublication peer review while letting the low-end ones that confuse correlation and causation remain in print.

Peer review and trust.

Researchers have peer reviewed manuscripts prior to publishing them in a variety of ways since the 18th century. The main goal of this practice is to improve the relevance and accuracy of scientific discussions. Even though experts often criticize peer review for a number of reasons, the process is still often considered the "gold standard" of science. Occasionally however, peer review approves studies that are later found to be wrong and rarely deceptive or fraudulent results are discovered prior to publication. Thus, there seems to be an element of discord between the ideology behind and the practice of peer review. By failing to effectively communicate that peer review is imperfect, the message conveyed to the wider public is that studies published in peer-reviewed journals are "true" and that peer review protects the literature from flawed science. A number of well-established criticisms exist of many elements of peer review. In the following we describe cases of the wider impact inappropriate peer review can have on public understanding of scientific literature.  Multiple examples across several areas of science find that scientists elevated the importance of peer review for research that was questionable or corrupted. For example, climate change deniers have published studies in the "Energy and Environment" journal, attempting to undermine the body of research that shows how human activity impacts the Earth's climate. Politicians in the United States who reject the established science of climate change have then cited this journal on several occasions in speeches and reports.  At times, peer review has been exposed as a process that was orchestrated for a preconceived outcome. "The New York Times" gained access to confidential peer review documents for studies sponsored by the "National Football Leagues" (NFL) that were cited as scientific evidence that brain injuries do not cause long-term harm to its players. During the peer review process, the authors of the study stated that all NFL players were part of a study, a claim that the reporters found to be false by examining the database used for the research. Furthermore, "The Times" noted that the NFL sought to legitimize the studies" methods and conclusion by citing a "rigorous, confidential peer-review process" despite evidence that some peer reviewers seemed "desperate" to stop their publication. Recent research has also demonstrated that widespread industry funding for published medical research often goes undeclared and that such conflicts of interest are not appropriately addressed by peer review.  Another problem that peer review fails to catch is ghostwriting, a process by which companies draft articles for academics who then publish them in journals, sometimes with little or no changes. These studies can then be used for political, regulatory and marketing purposes. In 2010, the US Senate Finance Committee released a report that found this practice was widespread, that it corrupted the scientific literature and increased prescription rates. Ghostwritten articles have appeared in dozens of journals, involving professors at several universities.  Just as experts in a particular field have a better understanding of the value of papers published in their area, scientists are considered to have better grasp of the value of published papers than the general public and to see peer review as a human process, with human failings, and that "despite its limitations, we need it. It is all we have, and it is hard to imagine how we would get along without it". But these subtleties are lost on the general public, who are often misled into thinking that published in a journal with peer review is the "gold standard" and can erroneously equate published research with the truth. Thus, more care must be taken over how peer review, and the results of peer reviewed research, are communicated to non-specialist audiences; particularly during a time in which a range of technical changes and a deeper appreciation of the complexities of peer review are emerging. This will be needed as the scholarly publishing system has to confront wider issues such as retractions and replication or reproducibility "crisis'.

Views of peer review.

Peer review is often considered integral to scientific discourse in one form or another. Its gatekeeping role is supposed to be necessary to maintain the quality of the scientific literature and avoid a risk of unreliable results, inability to separate signal from noise, and slow scientific progress.  Shortcomings of peer review have been met with calls for even stronger filtering and more gatekeeping. A common argument in favor of such initiatives is the belief that this filter is needed to maintain the integrity of the scientific literature.  Calls for more oversight have at least two implications that are counterintuitive of what is known to be true scholarship.  Others argue that authors most of all have a vested interest in the quality of a particular piece of work. Only the authors could have, as Feynman (1974) puts it, the "extra type of integrity that is beyond not lying, but bending over backwards to show how you're maybe wrong, that you ought to have when acting as a scientist." If anything, the current peer review process and academic system could penalize, or at least fail to incentivize, such integrity.  Instead, the credibility conferred by the "peer-reviewed" label could diminish what Feynman calls the "culture of doubt" necessary for science to operate a self-correcting, truth-seeking process. The effects of this can be seen in the ongoing replication crisis, hoaxes, and widespread outrage over the inefficacy of the current system. It's common to think that more oversight is the answer, as peer reviewers are not at all lacking in skepticism. But the issue is not the skepticism shared by the select few who determine whether an article passes through the filter. It is the validation, and accompanying lack of skepticism, that comes afterwards. Here again more oversight only adds to the impression that peer review ensures quality, thereby further diminishing the culture of doubt and counteracting the spirit of scientific inquiry.  Quality research - even some of our most fundamental scientific discoveries - dates back centuries, long before peer review took its current form. Whatever peer review existed centuries ago, it took a different form than it does in modern times, without the influence of large, commercial publishing companies or a pervasive culture of publish or perish. Though in its initial conception it was often a laborious and time-consuming task, researchers took peer review on nonetheless, not out of obligation but out of duty to uphold the integrity of their own scholarship. They managed to do so, for the most part, without the aid of centralised journals, editors, or any formalised or institutionalised process whatsoever. Supporters of modern technology argue that it makes it possible to communicate instantaneously with scholars around the globe, make such scholarly exchanges easier, and restore peer review to a purer scholarly form, as a discourse in which researchers engage with one another to better clarify, understand, and communicate their insights.  Such modern technology includes posting results to preprint servers, preregistration of studies, open peer review, and other open science practices. In all these initiatives, the role of gatekeeping remains prominent, as if a necessary feature of all scholarly communication, but critics argue that a proper, real-world implementation could test and disprove this assumption; demonstrate researchers' desire for more that traditional journals can offer; show that researchers can be entrusted to perform their own quality control independent of journal-coupled review. Jon Tennant also argues that the outcry over the inefficiencies of traditional journals centers on their inability to provide rigorous enough scrutiny, and the outsourcing of critical thinking to a concealed and poorly-understood process. Thus, the assumption that journals and peer review are required to protect scientific integrity seems to undermine the very foundations of scholarly inquiry.  To test the hypothesis that filtering is indeed unnecessary to quality control, many of the traditional publication practices would need to be redesigned, editorial boards repurposed if not disbanded, and authors granted control over the peer review of their own work. Putting authors in charge of their own peer review is seen as serving a dual purpose. On one hand, it removes the conferral of quality within the traditional system, thus eliminating the prestige associated with the simple act of publishing. Perhaps paradoxically, the removal of this barrier might actually result in an increase of the quality of published work, as it eliminates the cachet of publishing for its own sake. On the other hand, readers know that there is no filter so they must interpret anything they read with a healthy dose of skepticism, thereby naturally restoring the culture of doubt to scientific practice.  In addition to concerns about the quality of work produced by well-meaning researchers, there are concerns that a truly open system would allow the literature to be populated with junk and propaganda by those with a vested interest in certain issues. A counterargument is that the conventional model of peer review diminishes the healthy skepticism that is a hallmark of scientific inquiry, and thus confers credibility upon subversive attempts to infiltrate the literature. Allowing such "junk" to be published could make individual articles less reliable but render the overall literature more robust by fostering a "culture of doubt".  One initiative experimenting in this area is Researchers.One, a non-profit peer review publication platform featuring a novel author-driven peer review process. Other similar examples include the Self-Journal of Science, PRElights, and The Winnower, which do not yet seem to have greatly disrupted the traditional peer review workflow. Supporters conclude that researchers are more than responsible and competent enough to ensure their own quality control; they just need the means and the authority to do so.

Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review methods are used to maintain quality standards, improve performance, and provide credibility. In academia, scholarly peer review is often used to determine an academic paper's suitability for publication. Peer review can be categorized by the type of activity and by the field or profession in which the activity occurs, e.g., medical peer review.

Ein oder eine Peer-Review (englisch von "Peer", Gleichrangiger und "Review", Begutachtung, seltener : Kreuzgutachten) ist ein Verfahren zur Qualitätssicherung einer wissenschaftlichen Arbeit oder eines Projektes durch unabhängige Gutachter aus dem gleichen Fachgebiet.


Development.

The Le Prieur rocket was essentially a cardboard tube filled with 200 grams of black powder with a wooden conical head attached (by doped paper or linen tape) and had a triangular knife blade inserted in a slot across its apex forming a spear point. A square-section wooden stick (usually pine) was taped to the fish with about extending back from the base of the rocket and fitted snugly into a launch tube attached to the aircraft inter-plane struts.  As top French military officers had expressed concerns about fire hazard for the attacking aircraft, Yves Le Prieur first experimented with his weapon by fitting one on a short section of a Voisin aircraft wing bolted on a Piccard Pictet (Pic-Pic) automobile (one of the few period cars with a genuine 120 km/h capability). As the tests went on with full success, the weapon was soon put into active service.

Method of use.

The rockets were fired electrically from the interplane struts supporting the wings of biplanes via a cockpit switch. The switch launched all the rockets consecutively. The rockets were generally fired at a range of 100–150 metres with the aircraft at an inclined dive angle of 45 degrees. The steeper the dive the straighter the trajectory and the more accurate the attack. Attacks were made in the direction of the length of the balloon and against the wind, the pilot taking aim via the plane's existing gun-sight. However, the ignition and discharge of each rocket did not occur immediately and a delay varied slightly from one rocket to another. Thus the pilot had to continue to hold the target in his gun-sight and the dive continued until the last rocket discharged.  It successfully brought down observation balloons, but never managed to bring down a Zeppelin, although it was used to defend the United Kingdom from Zeppelin raids.  Amongst users of the rockets were France, United Kingdom, Belgium, and Germany. After planes became equipped with tracer rounds and incendiary bullets which were highly effective against hydrogen filled aerostats, the rockets were gradually abandoned through 1918. Aircraft that were armed with the rockets included the Nieuport 11/16/17, SPAD 7/13, Sopwith Baby/Pup/Camel, Farman HF.20/21, and the B.E.2/B.E.12. They were usually armed with eight rockets but the SPAD 7 carried six and the B.E.12 had ten.  The Pioneers-Yves Le Prieur

"Le Prieur" rockets (French "Fusées Le Prieur") were a type of incendiary air-to-air rockets used in World War I against observation balloons and airships. They were invented by the French Lieutenant Yves Le Prieur and were first used in the Battle of Verdun in April 1916. Due to great inaccuracy their range was limited to about.

Le-Prieur-Raketen (fr.: "fusées Le Prieur") waren während des Ersten Weltkrieges von den Westalliierten eingesetzte Luft-Luft-Raketen, die zum Abschuss feindlicher Fesselballons und Luftschiffe verwendet werden sollten.


Graph theory.

Incidence matrices are frequently used in graph theory.

Undirected and directed graphs.

In graph theory an undirected graph has two kinds of incidence matrices: unoriented and oriented.  The "unoriented incidence matrix" (or simply "incidence matrix") of an undirected graph is a matrix "B", where "n" and "m" are the numbers of vertices and edges respectively, such that if the vertex "v" and edge "e" are incident and 0 otherwise.  For example the incidence matrix of the undirected graph shown on the right is a matrix consisting of 4 rows (corresponding to the four vertices, 1–4) and 4 columns (corresponding to the four edges, e1–e4): If we look at the incidence matrix, we see that the sum of each column is equal to 2. This is because each edge has a vertex connected to each end.  The "incidence matrix" of a directed graph is a matrix "B" where "n" and "m" are the number of vertices and edges respectively, such that if the edge "e" leaves vertex "v", 1 if it enters vertex "v" and 0 otherwise (many authors use the opposite sign convention).  The "oriented incidence matrix" of an undirected graph is the incidence matrix, in the sense of directed graphs, of any orientation of the graph. That is, in the column of edge "e", there is one 1 in the row corresponding to one vertex of "e" and one −1 in the row corresponding to the other vertex of "e", and all other rows have 0. The oriented incidence matrix is unique up to negation of any of the columns, since negating the entries of a column corresponds to reversing the orientation of an edge.  The unoriented incidence matrix of a graph "G" is related to the adjacency matrix of its line graph "L"("G") by the following theorem:  where "A"("L"("G")) is the adjacency matrix of the line graph of "G", "B"("G") is the incidence matrix, and I is the identity matrix of dimension "m".  The discrete Laplacian (or Kirchhoff matrix) is obtained from the oriented incidence matrix "B"("G") by the formula  The integral cycle space of a graph is equal to the null space of its oriented incidence matrix, viewed as a matrix over the integers or real or complex numbers. The binary cycle space is the null space of its oriented or unoriented incidence matrix, viewed as a matrix over the two-element field.

Signed and bidirected graphs.

The incidence matrix of a signed graph is a generalization of the oriented incidence matrix. It is the incidence matrix of any bidirected graph that orients the given signed graph. The column of a positive edge has a 1 in the row corresponding to one endpoint and a −1 in the row corresponding to the other endpoint, just like an edge in an ordinary (unsigned) graph. The column of a negative edge has either a 1 or a −1 in both rows. The line graph and Kirchhoff matrix properties generalize to signed graphs.

Multigraphs.

The definitions of incidence matrix apply to graphs with loops and multiple edges. The column of an oriented incidence matrix that corresponds to a loop is all zero, unless the graph is signed and the loop is negative; then the column is all zero except for ±2 in the row of its incident vertex.

Hypergraphs.

Because the edges of ordinary graphs can only have two vertices (one at each end), the column of an incidence matrix for graphs can only have two non-zero entries. By contrast, a hypergraph can have multiple vertices assigned to one edge; thus, a general matrix of non-negative integers describes a hypergraph.

Incidence structures.

The "incidence matrix" of an incidence structure "C" is a matrix "B" (or its transpose), where "p" and "q" are the number of "points" and "lines" respectively, such that if the point "p" and line "L" are incident and 0 otherwise. In this case, the incidence matrix is also a biadjacency matrix of the Levi graph of the structure. As there is a hypergraph for every Levi graph, and "vice versa", the incidence matrix of an incidence structure describes a hypergraph.

Finite geometries.

An important example is a finite geometry. For instance, in a finite plane, "X" is the set of points and "Y" is the set of lines. In a finite geometry of higher dimension, "X" could be the set of points and "Y" could be the set of subspaces of dimension one less than the dimension of the entire space (hyperplanes); or, more generally, "X" could be the set of all subspaces of one dimension "d" and "Y" the set of all subspaces of another dimension "e", with incidence defined as containment.

Polytopes.

In a similar manner, the relationship between cells whose dimensions differ by one in a polytope, can be represented by an incidence matrix.

Block designs.

Another example is a block design. Here "X" is a finite set of "points" and "Y" is a class of subsets of "X", called "blocks", subject to rules that depend on the type of design. The incidence matrix is an important tool in the theory of block designs. For instance, it can be used to prove Fisher's inequality, a fundamental theorem of balanced incomplete 2-designs (BIBDs), that the number of blocks is at least the number of points. Considering the blocks as a system of sets, the permanent of the incidence matrix is the number of systems of distinct representatives (SDRs).

In mathematics, an incidence matrix is a matrix that shows the relationship between two classes of objects. If the first class is "X" and the second is "Y", the matrix has one row for each element of "X" and one column for each element of "Y". The entry in row "x" and column "y" is 1 if "x" and "y" are related (called "incident" in this context) and 0 if they are not. There are variations; see below.

Eine Inzidenzmatrix eines Graphen ist eine Matrix, welche die Beziehungen der Knoten und Kanten des Graphen speichert. Wenn der Graph formula_1 Knoten und formula_2 Kanten besitzt, ist seine Inzidenzmatrix eine formula_3-Matrix. Der Eintrag in der formula_4-ten Zeile und formula_5-ten Spalte gibt an, ob der formula_4-te Knoten Teil der formula_5-ten Kante ist. Steht an dieser Stelle eine 1, ist eine Inzidenzbeziehung gegeben, bei einer 0 liegt keine Inzidenz vor. Es wird davon ausgegangen, dass die Knoten von 1 bis formula_1 und die Kanten von 1 bis formula_2 durchnummeriert sind.


Biography.

Early life.

Acuff was born on September 15, 1903 in Maynardville, Tennessee, to Ida (née Carr) and Simon E. Neill Acuff, the third of their five children. Roy Acuff is of English ancestry, and his ancestors came to North America during the colonial era, settling in the mountains of Virginia and the Carolinas. The Acuffs were a fairly prominent family in Union County. Roy's paternal grandfather, Coram Acuff, had been a Tennessee state senator, and his maternal grandfather was a local physician. Roy's father was an accomplished fiddler and a Baptist preacher, his mother was proficient on the piano, and during Roy's early years the Acuff house was a popular place for local gatherings. At such gatherings, Roy would often amuse people by balancing farm tools on his chin. He also learned to play the harmonica and jaw harp at an early age.  In 1919, the Acuff family relocated to Fountain City (now a suburb of Knoxville), a few miles south of Maynardville. Roy attended Central High School, where he sang in the school chapel's choir and performed in "every play they had." His primary passion, however, was athletics. He was a three-sport standout at Central and, after graduating in 1925, was offered a scholarship to Carson-Newman University but turned it down. He played with several small baseball clubs around Knoxville, worked at odd jobs, and occasionally boxed.  In 1929, Acuff tried out for the Knoxville Smokies, a minor-league baseball team then affiliated with the New York Giants (now the San Francisco Giants). A series of collapses in spring training following a sunstroke, however, ended his baseball career. The effects left him ill for several years, and he suffered a nervous breakdown in 1930. "I couldn't stand any sunshine at all," he later recalled. While recovering, Acuff began to hone his fiddle skills, often playing on the family's front porch after the sun went down. His father gave him several records of regionally renowned fiddlers, such as Fiddlin' John Carson and Gid Tanner, which were important influences on his early style.

Early music career.

In 1932, Dr. Hauer's medicine show, which toured the southern Appalachian region, hired Acuff as one of its entertainers. The purpose of the entertainers was to draw a large crowd to whom Hauer could sell medicines (of suspect quality) for various ailments. While on the medicine show circuit, Acuff met the legendary Appalachian banjoist Clarence Ashley, from whom he learned "The House of the Rising Sun" and "Greenback Dollar", both of which Acuff later recorded. As the medicine show lacked microphones, Acuff learned to sing loud enough to be heard above the din, a skill that would later help him stand out on early radio broadcasts.  In 1934, Acuff left the medicine show circuit and began playing at local shows with various musicians in the Knoxville area, where he had become a celebrity and fixture in local newspaper columns. That year, the guitarist Jess Easterday and the Hawaiian guitarist Clell Summey joined Acuff to form the Tennessee Crackerjacks, which performed regularly on the Knoxville radio stations WROL and WNOX (the band moved back and forth between stations as Acuff bickered with their managers about compensation). Within a year, the group had added the bassist Red Jones and changed its name to the Crazy Tennesseans after being introduced as such by a WROL announcer named Alan Stout. Fans often remarked to Acuff how "clear" his voice was coming through over the radio, important in an era when singers were often drowned out by string band cacophony. The popularity of Acuff's rendering of the song "The Great Speckled Bird" helped the group land a contract with ARC, for which they recorded several dozen tracks (including the band's best-known track, "Wabash Cannonball") in 1936. Needing to complete a 20-song commitment, the band recorded two ribald tunes—including "When Lulu's Gone"—but released them under a pseudonym, the Bang Boys. The group split from ARC in 1937 over a separate contract dispute.

Grand Ole Opry.

In 1938, the Crazy Tennesseans moved to Nashville to audition for the Grand Ole Opry. Although their first audition went poorly, the band's second audition impressed Opry founder George D. Hay and producer Harry Stone, and they offered the group a contract later that year. On Hay and Stone's suggestion, Acuff changed the group's name to the Smoky Mountain Boys, referring to the mountains near where he and his bandmates grew up. Shortly after the band joined the Opry, Clell Summey left the group and was replaced by the dobro player Beecher (Pete) Kirby—best known by his stage name Bashful Brother Oswald—whom Acuff had met in a Knoxville bakery earlier that year. Acuff's powerful lead vocals and Kirby's dobro playing and high-pitched backing vocals gave the band its distinctive sound. By 1939, Jess Easterday had switched to bass to replace Red Jones, and Acuff had added the guitarist Lonnie "Pap" Wilson and the banjoist Rachel Veach to fill out the band's lineup. Within a year, Roy Acuff and the Smoky Mountain Boys rivaled the long-time Opry banjoist Uncle Dave Macon as the troupe's most popular act. In the same period, he was initiated to the Masonic Lodge of East Nashville No. 560.  In spring 1940, Acuff and his band traveled to Hollywood, where they appeared with Hay and Macon in the motion picture "Grand Ole Opry". Acuff appeared in several subsequent B-movies, including "O, My Darling Clementine" (1943), in which he played a singing sheriff; "Night Train to Memphis" (1946), the title of which comes from a song Acuff recorded in 1940; and "Home in San Antone" (1949), in which he starred with Lloyd Corrigan and William Frawley.  Acuff and his band also joined Macon and other Opry acts at various tent shows held throughout the Southeast in the early 1940s. The crowds at these shows were so large that roads leading into the venues were jammed with traffic for miles. Starting in 1939, Acuff hosted the Opry's "Prince Albert" segment. He left the show in 1946 after a dispute with management.

Acuff-Rose.

In 1942, Acuff and songwriter Fred Rose (1897–1954) formed Acuff-Rose Music. Acuff originally sought the company to publish his own music, but soon realized there was a high demand from other country artists, many of whom had been exploited by larger publishing firms. Due in large part to Rose's ASCAP connections and gifted ability as a talent scout, Acuff-Rose quickly became the most important publishing company in country music. In 1946, the company signed Hank Williams, and in 1950 published their first major hit, Patti Page's rendition of "Tennessee Waltz".

Political ambitions.

In 1943, Acuff was initiated into the East Nashville Freemasonic Lodge in Tennessee, of which he would remain a lifelong member. Later that same year, Acuff invited Tennessee Governor Prentice Cooper to be the guest of honor at a gala held to mark the nationwide premiere of the Opry's "Prince Albert" show. Cooper rejected the offer, however, and lambasted Acuff and his "disgraceful" music for making Tennessee the "hillbilly capital of the United States." A Nashville journalist reported the governor's comments to Acuff and suggested Acuff run for governor himself. While Acuff initially did not take the suggestion seriously, he did accept the Republican Party nomination for governor in 1948.  Acuff's nomination caused great concern for E. H. Crump, the head of a Memphis Democratic Party political machine that had dominated Tennessee state politics for nearly a quarter-century. Crump was not worried so much about losing the governor's office—in spite of Acuff's name recognition—but did worry that Acuff would draw large crowds to Republican rallies and bolster other statewide candidates. While Acuff did relatively well and helped reinvigorate Tennessee's Republicans, his opponent, Gordon Browning, still won with 67 percent of the vote.

Later career.

After leaving the Opry, Acuff spent several years touring the Western United States, although demand for his appearances dwindled with the lack of national exposure and the rise of musicians such as Ernest Tubb and Eddy Arnold, who were more popular with younger audiences. He eventually returned to the Opry, although by the 1960s, his record sales had dropped off considerably. After nearly losing his life in an automobile accident outside of Sparta, Tennessee, in 1965, Acuff pondered retiring, making only token appearances on the Opry stage and similar shows, and occasionally performing duos with long-time bandmate Bashful Brother Oswald.  In 1972, Acuff's career received a brief resurgence in the folk revival movement after he appeared on the Nitty Gritty Dirt Band album, "Will the Circle Be Unbroken". The appearance paved the way for one of the defining moments of Acuff's career, which came on the night of March 16, 1974, when the Opry officially moved from the Ryman Auditorium to the Grand Ole Opry House at Opryland. The first show at the new venue opened with a huge projection of a late-1930s image of Roy Acuff and the Smoky Mountain Boys onto a large screen above the stage. A recording from one of the band's 1939 appearances was played over the sound system, with the iconic voice of George Hay introducing the band, followed by the band's performance of "Wabash Cannonball". That same night, Acuff showed President Richard Nixon, an honored guest at the event, how to yo-yo, and convinced the president to play several songs on the piano.  In the early 1980s, after the death of his wife, Mildred, Acuff, then in his 80s, moved into a small house on the Opryland grounds and continued performing daily on stage. He arrived early most days at the Opry before the shows and performed odd jobs, such as stocking soda in backstage refrigerators. He made a cameo appearance in the music video for Moe Bandy and Joe Stampley's 1984 parody hit song "Where's The Dress?" In 1991, he was awarded the National Medal of Arts, and given a lifetime achievement award by the John F. Kennedy Center for the Performing Arts, the first Country music act to receive the esteemed honor. Roy Acuff died in Nashville on November 23, 1992 of congestive heart failure at the age of 89.

Repertoire and legacy.

Many of Acuff's songs show a strong religious influence, most notably "Great Speckled Bird", "The Prodigal Son" and "Lord, Build Me a Cabin". Such songs were typically set to a traditional Anglo-Celtic melody, which is most apparent on "Great Speckled Bird" and the 1940 recording "The Precious Jewel". Acuff performed popular songs of the day, including Pee Wee King's "Tennessee Waltz" and Dorsey Dixon's "I Didn't Hear Nobody Pray", the latter of which he appropriated and renamed "Wreck on the Highway". He also recorded a version of the Cajun fiddler Harry Choates's "Jole Blon". Traditional recordings included "Greenback Dollar", which he probably learned from Clarence Ashley while on the medicine show circuit, and "Lonesome Old River Blues", which he recorded with the Smoky Mountain Boys in the 1940s. Acuff and the Crazy Tennesseans recorded "Wabash Cannonball"—another traditional song—in 1936, although Acuff did not provide the vocals on this early recording. The better-known version of the song with Acuff providing the vocals was recorded in 1947.  In 1979, Opryland opened the Roy Acuff Theatre, which was dedicated in Acuff's honor (it was demolished in 2011 after suffering extensive damage in the 2010 Tennessee floods). Dunbar Cave State Natural Area was established in 1973 from a recreational area the state had purchased from Mrs. McKay King. The cave was owned by Acuff from 1948 to 1963. Two museums have been named in Acuff's honor—the Roy Acuff Museum at Opryland (now closed) and the Roy Acuff Union Museum and Library in his hometown of Maynardville. Acuff has a star on the Hollywood Walk of Fame located at 1541 Vine Street. He is pictured with other country singers at the new Smoky Mountain Opera in Pigeon Forge, Tennessee.

Roy Claxton Acuff (September 15, 1903 – November 23, 1992) was an American country music singer, fiddler, promoter, and freemason. Known as the "King of Country Music", Acuff is often credited with moving the genre from its early string band and "hoedown" format to the singer-based format that helped make it internationally successful. In 1952, Hank Williams told Ralph Gleason, "He's the biggest singer this music ever knew. You booked him and you didn't worry about crowds. For drawing power in the South, it was Roy Acuff, then God."

Roy Claxton Acuff (* 15. September 1903 in Maynardville, Tennessee; † 23. November 1992 in Nashville, Tennessee) war ein US-amerikanischer Countrysänger und Musikverleger. Er war einer der größten und einflussreichsten Stars der Countrymusik in der Zeit zwischen dem Tod von Jimmie Rodgers 1933 und dem Aufstieg von Hank Williams Ende der 1940er Jahre. Er verkaufte mehr als dreißig Millionen Schallplatten und wurde mit den größten Ehrungen seines Genres ausgezeichnet.


Chemistry.

Notation.

The chemical formula for kaolinite as used in mineralogy is, however, in ceramics applications the formula is typically written in terms of oxides, thus the formula for kaolinite is.

Structural transformations.

Kaolinite group clays undergo a series of phase transformations upon thermal treatment in air at atmospheric pressure.

Drying.

Below, exposure to dry air will slowly remove liquid water from the kaolin. The end-state for this transformation is referred to as "leather dry". Between 100 °C and about, any remaining liquid water is expelled from kaolinite. The end state for this transformation is referred to as "bone dry". Throughout this temperature range, the expulsion of water is reversible: if the kaolin is exposed to liquid water, it will be reabsorbed and disintegrate into its fine particulate form. Subsequent transformations are "not" reversible, and represent permanent chemical changes.

Metakaolin.

Endothermic dehydration of kaolinite begins at 550–600 °C producing disordered metakaolin, but continuous hydroxyl loss is observed up to. Although historically there was much disagreement concerning the nature of the metakaolin phase, extensive research has led to a general consensus that metakaolin is not a simple mixture of amorphous silica () and alumina (), but rather a complex amorphous structure that retains some longer-range order (but not strictly crystalline) due to stacking of its hexagonal layers.<chem>Al2Si2O5(OH)4 -> Al2Si2O7 + 2 H2O</chem>

Spinel.

Further heating to 925–950 °C converts metakaolin to an aluminium-silicon spinel which is sometimes also referred to as a gamma-alumina type structure:<chem>2 Al2Si2O7 -> Si3Al4O12 + SiO2</chem>

Platelet mullite.

Upon calcination above 1050 °C, the spinel phase nucleates and transforms to platelet mullite and highly crystalline cristobalite:<chem>3 Si3Al4O12 -> 2(3 Al2O3. 2 SiO2) + 5 SiO2</chem>

Needle mullite.

Finally, at 1400 °C the "needle" form of mullite appears, offering substantial increases in structural strength and heat resistance. This is a structural but not chemical transformation. See stoneware for more information on this form.

Occurrence.

Kaolinite is one of the most common minerals; it is mined, as kaolin, in Malaysia, Pakistan, Vietnam, Brazil, Bulgaria, Bangladesh, France, the United Kingdom, Iran, Germany, India, Australia, South Korea, the People's Republic of China, the Czech Republic, Spain, South Africa, and the United States.  Mantles of kaolinitic saprolite are common in Western and Northern Europe. The ages of these mantles are Mesozoic to Early Cenozoic.  Kaolinite clay occurs in abundance in soils that have formed from the chemical weathering of rocks in hot, moist climates—for example in tropical rainforest areas. Comparing soils along a gradient towards progressively cooler or drier climates, the proportion of kaolinite decreases, while the proportion of other clay minerals such as illite (in cooler climates) or smectite (in drier climates) increases. Such climatically-related differences in clay mineral content are often used to infer changes in climates in the geological past, where ancient soils have been buried and preserved.  In the "Institut National pour l'Etude Agronomique au Congo Belge" (INEAC) classification system, soils in which the clay fraction is predominantly kaolinite are called "kaolisol" (from kaolin and soil).  In the US, the main kaolin deposits are found in central Georgia, on a stretch of the Atlantic Seaboard fall line between Augusta and Macon. This area of thirteen counties is called the "white gold" belt; Sandersville is known as the "Kaolin Capital of the World" due to its abundance of kaolin. In the late 1800s, an active kaolin surface-mining industry existed in the extreme southeast corner of Pennsylvania, near the towns of Landenberg and Kaolin, and in what is present-day White Clay Creek Preserve. The product was brought by train to Newark, Delaware, on the Newark-Pomeroy line, along which can still be seen many open-pit clay mines. The deposits were formed between the late Cretaceous and early Paleogene, about 100 to 45 million years ago, in sediments derived from weathered igneous and metakaolin rocks. Kaolin production in the US during 2011 was 5.5 million tons.  During the Paleocene–Eocene Thermal Maximum sediments were enriched with kaolinite from a detrital source due to denudation.

Synthesis and genesis.

Difficulties are encountered when trying to explain kaolinite formation under atmospheric conditions by extrapolation of thermodynamic data from the more successful high-temperature syntheses (as for example Meijer and Van der Plas, 1980 have pointed out). La Iglesia and Van Oosterwijk-Gastuche (1978) thought that the conditions under which kaolinite will nucleate can be deduced from stability diagrams, based as they are on dissolution data. Because of a lack of convincing results in their own experiments, La Iglesia and Van Oosterwijk-Gastuche (1978) had to conclude, however, that there were other, still unknown, factors involved in the low-temperature nucleation of kaolinite. Because of the observed very slow crystallization rates of kaolinite from solution at room temperature Fripiat and Herbillon (1971) postulated the existence of high activation energies in the low-temperature nucleation of kaolinite.  At high temperatures, equilibrium thermodynamic models appear to be satisfactory for the description of kaolinite dissolution and nucleation, because the thermal energy suffices to overcome the energy barriers involved in the nucleation process. The importance of syntheses at ambient temperature and atmospheric pressure towards the understanding of the mechanism involved in the nucleation of clay minerals lies in overcoming these energy barriers. As indicated by Caillère and Hénin (1960) the processes involved will have to be studied in well-defined experiments, because it is virtually impossible to isolate the factors involved by mere deduction from complex natural physico-chemical systems such as the soil environment. Fripiat and Herbillon (1971), in a review on the formation of kaolinite, raised the fundamental question how a disordered material (i.e., the amorphous fraction of tropical soils) could ever be transformed into a corresponding ordered structure. This transformation seems to take place in soils without major changes in the environment, in a relatively short period of time, and at ambient temperature (and pressure).  Low-temperature synthesis of clay minerals (with kaolinite as an example) has several aspects. In the first place the silicic acid to be supplied to the growing crystal must be in a monomeric form, i.e., silica should be present in very dilute solution (Caillère et al., 1957; Caillère and Hénin, 1960; Wey and Siffert, 1962; Millot, 1970). In order to prevent the formation of amorphous silica gels precipitating from supersaturated solutions without reacting with the aluminium or magnesium cations to form crystalline silicates, the silicic acid must be present in concentrations below the maximum solubility of amorphous silica. The principle behind this prerequisite can be found in structural chemistry: "Since the polysilicate ions are not of uniform size, they cannot arrange themselves along with the metal ions into a regular crystal lattice." (Iler, 1955, p. 182)  The second aspect of the low-temperature synthesis of kaolinite is that the aluminium cations must be hexacoordinated with respect to oxygen (Caillère and Hénin, 1947; Caillère et al., 1953; Hénin and Robichet, 1955). Gastuche et al. (1962), as well as Caillère and Hénin (1962) have concluded, that only in those instances when the aluminium hydroxide is in the form of gibbsite, kaolinite can ever be formed. If not, the precipitate formed will be a "mixed alumino-silicic gel" (as Millot, 1970, p. 343 put it). If it were the only requirement, large amounts of kaolinite could be harvested simply by adding gibbsite powder to a silica solution. Undoubtedly a marked degree of adsorption of the silica in solution by the gibbsite surfaces will take place, but, as stated before, mere adsorption does not create the layer lattice typical of kaolinite crystals.  The third aspect is that these two initial components must be incorporated into one and the same mixed crystal with a layer structure. From the following equation (as given by Gastuche and DeKimpe, 1962) for kaolinite formation<chem>2Al(OH)3 + 2H4SiO4 -> Si2O5. 2Al(OH)3 + 5H2O</chem>it can be seen, that five molecules of water must be removed from the reaction for every molecule of kaolinite formed. Field evidence illustrating the importance of the removal of water from the kaolinite reaction has been supplied by Gastuche and DeKimpe (1962). While studying soil formation on a basaltic rock in Kivu (Zaïre), they noted how the occurrence of kaolinite depended on the of the area involved. A clear distinction was found between areas with good drainage (i.e., areas with a marked difference between wet and dry seasons) and those areas with poor drainage (i.e., perennially swampy areas). Only in the areas with distinct seasonal alternations between wet and dry was kaolinite found. The possible significance of alternating wet and dry conditions on the transition of allophane into kaolinite has been stressed by Tamura and Jackson (1953). The role of alternations between wetting and drying on the formation of kaolinite has also been noted by Moore (1964).

Laboratory syntheses.

Syntheses of kaolinite at high temperatures (more than ) are relatively well known. There are for example the syntheses of Van Nieuwenberg and Pieters (1929); Noll (1934); Noll (1936); Norton (1939); Roy and Osborn (1954); Roy (1961); Hawkins and Roy (1962); Tomura et al. (1985); Satokawa et al. (1994) and Huertas et al. (1999). Relatively few low-temperature syntheses have become known (cf. Brindley and DeKimpe (1961); DeKimpe (1969); Bogatyrev et al. (1997)).  Laboratory syntheses of kaolinite at room temperature and atmospheric pressure have been described by DeKimpe et al. (1961). From those tests the role of periodicity becomes convincingly clear. DeKimpe et al. (1961) had used daily additions of alumina (as ) and silica (in the form of ethyl silicate) during at least two months. In addition, adjustments of the pH took place every day by way of adding either hydrochloric acid or sodium hydroxide. Such daily additions of Si and Al to the solution in combination with the daily titrations with hydrochloric acid or sodium hydroxide during at least 60 days will have introduced the necessary element of periodicity. Only now the actual role of what has been described as the "aging" ("Alterung") of amorphous alumino-silicates (as for example Harder, 1978 had noted) can be fully understood. Time as such is not bringing about any change in a closed system at equilibrium; but a series of alternations, of periodically changing conditions (by definition, taking place in an open system), will bring about the low-temperature formation of more and more of the stable phase kaolinite instead of (ill-defined) amorphous alumino-silicates.

Uses.

The main use of the mineral kaolinite (about 50% of the time) is the production of paper; its use ensures the gloss on some grades of coated paper.  Kaolin is also known for its capabilities to induce and accelerate blood clotting. In April 2008 the US Naval Medical Research Institute announced the successful use of a kaolinite-derived aluminosilicate infusion in traditional gauze, known commercially as QuikClot Combat Gauze, which is still the hemostat of choice for all branches of the US military.  Kaolin is used (or was used in the past):

Geophagy.

Humans sometimes eat kaolin for health or to suppress hunger, a practice known as geophagy. Consumption is greater among women, especially during pregnancy. This practice has also been observed within a small population of African-American women in the Southern United States, especially Georgia. There, the kaolin is called "white dirt", "chalk", or "white clay".

Safety.

People can be exposed to kaolin in the workplace by breathing in the powder or from skin or eye contact.

United States.

The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for kaolin exposure in the workplace as 15 mg/m total exposure and 5 mg/m respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 10 mg/m total exposure TWA 5 mg/m respiratory exposure over an 8-hour workday.

Kaolinite () is a clay mineral, part of the group of industrial minerals with the chemical composition AlSiO(OH). It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral sheet of alumina () octahedra. Rocks that are rich in kaolinite are known as kaolin or china clay.

Das Mineral Kaolinit ist ein sehr häufig vorkommendes Schichtsilikat aus der Kaolinit-Serpentin-Gruppe mit der kristallchemischen Zusammensetzung Al[(OH)|SiO]. Es ist ein typischer Vertreter der Zweischicht-Tonminerale. Kaolinit kristallisiert im triklinen Kristallsystem und entwickelt meist blättrige, schuppige, erdige oder massige Aggregate, selten aber auch pseudohexagonale Kristalle von überwiegend weißer Farbe. Durch Verunreinigungen kann seine Farbe aber auch ins rötliche, bräunliche oder bläuliche spielen. Seine Strichfarbe ist weiß. Kaolinit kann gesteinsbildend als Kaolin auftreten.


History.

The city's name is most commonly attributed to Muskogee origin, "Haiyakpo" (prairie) and "hili" (pretty) combining in "Hialeah" to mean "pretty prairie". Alternatively, the word is of Seminole origin meaning "Upland Prairie". The city is located upon a large prairie between Biscayne Bay and the Everglades.  The Seminole interpretation of its name, "High Prairie", evokes a picture of the grassy plains used by the native Indians coming from the everglades to dock their canoes and display their wares for the newcomers of Miami. This "high prairie" caught the eye of pioneer aviator Glenn Curtiss and Missouri cattleman James H. Bright in 1921. Together, they developed not only the town of Hialeah but also Hialeah Park Race Track.  In the early "Roaring '20s", Hialeah produced significant entertainment contributions. Sporting included the Spanish sport of jai alai and greyhound racing, and media included silent movies like D.W. Griffith's "The White Rose" which was made at the Miami Movie Studios located in Hialeah. However, the 1926 Miami hurricane brought many of these things to an end.  In the years since its incorporation in 1925, many historical events and people have been associated with Hialeah. The opening of the horse racing course at Hialeah Park Race Track in 1925 (which was nicknamed the "Grand Dame") received more coverage in the Miami media than any other sporting event in the history of Dade County up to that time and since then there have been countless horse racing histories played out at the world-famous park. It was considered one of the most grand of thoroughbred horse racing parks with its majestic Mediterranean style architecture and was considered the Jewel of Hialeah at the time.  The park's grandeur has attracted millions, included among them are names known around the world such as the Kennedy family, Harry Truman, General Omar Bradley, Winston Churchill, and J.P. Morgan. The Hialeah Park Race Track also holds the dual distinction of being an Audubon Bird Sanctuary due to its famous pink flamingos and being listed on the National Register of Historic Places. The famous aviator Amelia Earhart in 1937 said her final good-byes to the continental U.S. from Hialeah as she left on her ill-fated flight around the world in 1937.  While Hialeah was once envisioned as a playground for the elite, Cuban exiles, fleeing Fidel Castro's 1959 revolution as well as World War II veterans and city planners transformed the city into a working-class community. Hialeah historian Patricia Fernández-Kelly explained "It became an affordable Eden." She further describes the city as "a place where different groups have left their imprint while trying to create a sample of what life should be like." Several waves of Cuban exiles, starting after the Cuban Revolution in 1959 and continuing through to the Freedom Flights from 1965 to 1973, the Mariel boatlift in 1980, and the Balseros or boat people of the late 1990s, created what at least one expert has considered the most economically successful immigrant enclave in U.S. history as Hialeah is the only American industrial city that continues to grow.  From a population of 1,500 in 1925, Hialeah has grown at a rate faster than most of the 10 larger cities in the state of Florida since the 1960s and holds the rank of Florida's fifth-largest city, with more than 224,000 residents. The city is also one of the largest employers in Dade County.  In January 2009, "Forbes" magazine listed Hialeah as one of the most boring cities in the United States citing the city's large population and anonymity in the national media.

Geography.

Hialeah is located at (25.860474, -80.293971).  According to the United States Census Bureau, the city has a total area of. of it is land and of it (2.53%) is water.

Demographics.

Hialeah is the tenth-largest city in the United States among cities with a population density of more than 10,000 people per square mile.  As of 2010, there were 74,067 households, with 3.9% being vacant. As of 2000, 36.2% had children under the age of 18 living with them, 57.4% were married couples living together, 17.4% had a female householder with no husband present, and 18.7% were non-families. 14.7% of all households were made up of individuals and 7.8% had someone living alone who was 65 years of age or older. The average household size was 3.15 and the average family size was 3.39.  In 2015 through 2016 the population in Hialeah grew from 234,714 to 235,626, a 0.39% increase. The median household income grew from $29,249 to $29,817, a 1.94% increase.  In 2000, the age distribution of the population showed 23.0% under the age of 18, 8.2% from 18 to 24, 29.4% from 25 to 44, 22.9% from 45 to 64, and 16.6% who were 65 years of age or older. The median age was 43.5 years. For every 100 females, there were 92.7 males. For every 100 females age 18 and over, there were 89.6 males.  In 2000, the median income for a household in the city was $29,492, and the median income for a family was $31,621. Males had a median income of $23,133 versus $17,886 for females. The per capita income for the city was $12,402. About 16.0% of families and 18.6% of the population were below the poverty line, including 22.2% of those under age 18 and 22.4% of those age 65 or over.  As of 2010, Hialeah had the highest percentage of Cuban and Cuban American residents in the United States, with 73.37% of the populace. It had the forty-third highest percentage of Colombian and Colombian American residents in the US, at 3.16% of the city's population, and the eighty-fifth highest percentage of Dominican and Dominican American residents in the US, at 1.81% of its population. It also had the thirty-eighth highest percentage of Hondurans and Honduran American in the US, at 1.15%, while it had the eighth highest percentage of Nicaraguans and Nicaraguan American, at 4.07% of all residents.  Hialeah ranks #2 (nearby Hialeah Gardens ranks as #1) in the list of cities in the United States where Spanish is most spoken. As of 2000, 92.14% of the population spoke Spanish at home, while those who spoke only English made up 7.37% of the population. All other languages spoken were below 1% of the population.

Economy.

The city of Hialeah is a significant commercial center in Miami-Dade County. The city is host to national retailers such as Starbucks, Target, Best Buy, Walmart, Lowe's, and The Home Depot, as well as homegrown businesses such as Navarro and Sedano's.  Hialeah is also home to vibrant community of mom-and-pop stores. These shops have successfully competed against national name brand retailers, outfitters, and franchises. In order to remain competitive national businesses have altered their traditional business strategy to meet the demands of the local community. Publix supermarkets opened a Publix Sabor along one of the city's main streets which caters to Latin American and Hispanic clientele. While most of the manufacturing and cloth industries that made Hialeah an industrial city in the 1970s–1980s have disappeared, new electronics and technology businesses have reinvigorated the local economy.  Westland Mall contains over 100 stores and several restaurants. Macy's, J. C. Penney, and Sears are the main anchor stores located at the mall, while restaurants include Fuddruckers, IHOP, Los Ranchos Steakhouse, Chili's, Manchu Wok, and Edy's.  Telemundo, the second largest Spanish-language TV network in the United States, was headquartered at 2340 West 8th Avenue in Hialeah until 2018.

Recreation.

In March 2009, it was announced that a $40–$90 million restoration project was set to begin within the year on the Hialeah Park Race Track. On May 7, 2009 the Florida legislature agreed to a deal with the Seminole Tribe of Florida that allowed Hialeah Park to operate slot machines and run Quarter Horse races. The historic racetrack reopened on November 28, 2009 but only for Quarter Horse races. The park installed slot machines in January 2010 as part of a deal to allow for two calendar seasons of racing. The races went on all the way until February 2, 2010. Only a portion of the park has been restored, and an additional $30 million will be needed to complete this first phase of the project. The full transformation is expected to cost $1 billion since the plan includes a complete redevelopment of the surrounding area including the construction of an entertainment complex to include a hotel, restaurants, casinos, stores and a theater. In June 2010 concerns were raised over the preservation of Hialeah Park's historical status, as the planned development threatens to hurt Hialeah Park's status as a National Historic Landmark.  The City of Hialeah is home to three tennis centers, five public swimming pools and aquatic centers, and more than 14 public parks totaling more than combined. Milander Park features a municipal auditorium and a 10,000 seat football stadium.  Amelia Earhart Park also serves the Hialeah community. Located just south of the Opa Locka Airport, the park consists of 515 acres, including a five-acre Bark Park for dogs. It offers a variety of amenities, programs and activities including mountain biking, soccer, Tom Sawyer's Play Island and Bill Graham Farm Village. It also houses the new Miami Watersports Complex, which offers cable and boat wakeboarding, waterskiing, wake surfing, kneeboarding and paddleboarding.

Government and infrastructure.

The University of Florida College of Dentistry operates the Hialeah Dental Clinic. It opened in 1997 to serve Hispanic populations in South Florida.

Politics.

Hialeah is located within Florida's 25th Congressional District. It is currently represented in the House of Representatives by Mario Díaz-Balart, a Republican. According to the nonpartisan Bay Area Center for Voting Research (BACVR) Hialeah, Florida is the fourth most conservative city in the United States. The current mayor of Hialeah is Carlos Hernández.

Education.

Public primary and secondary schools.

Miami-Dade County Public Schools serves Hialeah.  Two high schools serving the Hialeah community, Mater Academy Charter High School and Miami Lakes Tech, were named as "Silver" award winners in "U.S. News & World Report"s "Best High Schools 2008 Search".

Public library.

Hialeah's public library was founded in 1924, one year prior to the incorporation of the city. While over the years the county-wide Miami-Dade Public Library System has taken over the libraries of most of the cities in the county, Hialeah public libraries function independently from the county-wide system. The first branch was a donation by the Hialeah Women's Club. It was actually located in the house of one of the Hialeah Women's Club's home. The home of Ms. J Sommers Garwood. The club was founded by Ms. Lua Adams Curtiss, who was the late mother of the famous aviator, Glen Curtiss. The club asked for donations to get the library started and was fortunate enough to receive enough to get the system started. The latest branch, John F. Kennedy Library is now the main library for Hialeah and is easily recognizable for its grand murals. In 2017, the branch set out to renovate the entire library and they added new furniture, the art murals, polished terrazzo floors, and new sculptures. The library hosts a print collection, digital resources, and a Hialeah History Collection which collects, preserves and provides access to information about the City of Hialeah's history.

Transportation.

In 2013, Hialeah was named a top five city with the worst drivers by "Slate" and Allstate.

Rail.

Hialeah is served by Miami-Dade Transit along major thoroughfares by Metrobus, and by the Miami Metrorail, Tri-Rail, and Amtrak at:  Metrorail:  Tri-Rail:  Amtrak:

Road.

"All Ways Lead to Hialeah" was one of the city's first slogans. At the time, Glenn Curtiss and James Bright could not have imagined the important link in the transportation chain provided by Hialeah's location. Sitting in the heart of northwest Dade, Hialeah has access to every major thoroughfare, linked by:

Hialeah () is a city in Miami-Dade County, Florida, United States. With the population of 233,339 at the 2019 United States Census, Hialeah is the sixth-largest city in Florida. It is a principal city of the Miami metropolitan area, which was home to an estimated 6,198,782 people at the 2018 census. It is located west-northwest of Miami, and is the only place in the county, other than Homestead, Florida, to have its own street grid numbered separately from the rest of the county (which is otherwise based on Miami Avenue at Flagler Street in downtown Miami, the county seat).

Hialeah ist eine Stadt im Miami-Dade County im US-Bundesstaat Florida mit 224.669 Einwohnern (Stand: 2010). Nach Miami ist Hialeah die größte Stadt des Miami-Dade County und der Metropolregion Miami.


Motivation.

A block cipher is one of the most basic primitives in cryptography, and frequently used for data encryption. However, by itself, it can only be used to encode a data block of a predefined size, called the block size. For example, a single invocation of the AES algorithm transforms a 128-bit plaintext block into a ciphertext block of 128 bits in size. The key, which is given as one input to the cipher, defines the mapping between plaintext and ciphertext. If data of arbitrary length is to be encrypted, a simple strategy is to split the data into blocks each matching the cipher's block size, and encrypt each block separately using the same key. This method is not secure as equal plaintext blocks get transformed into equal ciphertexts, and a third party observing the encrypted data may easily determine its content even when not knowing the encryption key.  To hide patterns in encrypted data while avoiding the re-issuing of a new key after each block cipher invocation, a method is needed to randomize the input data. In 1980, the NIST published a national standard document designated Federal Information Processing Standard(FIPS) PUB 81, which specified four so-called block cipher modes of operation, each describing a different solution for encrypting a set of input blocks. The first mode implements the simple strategy described above, and was specified as the electronic codebook (ECB) mode. In contrast, each of the other modes describe a process where ciphertext from one block encryption step gets intermixed with the data from the next encryption step. To initiate this process, an additional input value is required to be mixed with the first block, and which is referred to as an "initialization vector". For example, the cipher-block chaining (CBC) mode requires an unpredictable value of the cipher's block size as additional input, and adds it to the first plaintext block before subsequent encryption. In turn, the ciphertext produced in the first encryption step is added to the second plaintext block, and so on. The ultimate goal for encryption schemes is to provide semantic security: by this property, it is practically impossible for an attacker to draw any knowledge from observed ciphertext. It can be shown that each of the three additional modes specified by the NIST are semantically secure under so-called chosen-plaintext attacks.

Properties.

Properties of an IV depend on the cryptographic scheme used. A basic requirement is "uniqueness", which means that no IV may be reused under the same key. For block ciphers, repeated IV values devolve the encryption scheme into electronic codebook mode: equal IV and equal plaintext result in equal ciphertext. In stream cipher encryption uniqueness is crucially important as plaintext may be trivially recovered otherwise.  Many schemes require the IV to be "unpredictable" by an adversary. This is effected by selecting the IV at random or pseudo-randomly. In such schemes, the chance of a duplicate IV is negligible, but the effect of the birthday problem must be considered. As for the uniqueness requirement, a predictable IV may allow recovery of (partial) plaintext.  Depending on whether the IV for a cryptographic scheme must be random or only unique the scheme is either called "randomized" or "stateful". While randomized schemes always require the IV chosen by a sender to be forwarded to receivers, stateful schemes allow sender and receiver to share a common IV state, which is updated in a predefined way at both sides.

Block ciphers.

Block cipher processing of data is usually described as a mode of operation. Modes are primarily defined for encryption as well as authentication, though newer designs exist that combine both security solutions in so-called authenticated encryption modes. While encryption and authenticated encryption modes usually take an IV matching the cipher's block size, authentication modes are commonly realized as deterministic algorithms, and the IV is set to zero or some other fixed value.

Stream ciphers.

In stream ciphers, IVs are loaded into the keyed internal secret state of the cipher, after which a number of cipher rounds are executed prior to releasing the first bit of output. For performance reasons, designers of stream ciphers try to keep that number of rounds as small as possible, but because determining the minimal secure number of rounds for stream ciphers is not a trivial task, and considering other issues such as entropy loss, unique to each cipher construction, related-IVs and other IV-related attacks are a known security issue for stream ciphers, which makes IV loading in stream ciphers a serious concern and a subject of ongoing research.

WEP IV.

The 802.11 encryption algorithm called WEP (short for Wired Equivalent Privacy) used a short, 24-bit IV, leading to reused IVs with the same key, which led to it being easily cracked. Packet injection allowed for WEP to be cracked in times as short as several seconds. This ultimately led to the deprecation of WEP.

SSL 2.0 IV.

In cipher-block chaining mode (CBC mode), the IV must, in addition to being unique, be unpredictable at encryption time. In particular, the (previously) common practice of re-using the last ciphertext block of a message as the IV for the next message is insecure (for example, this method was used by SSL 2.0). If an attacker knows the IV (or the previous block of ciphertext) before he specifies the next plaintext, he can check his guess about plaintext of some block that was encrypted with the same key before. This is known as the TLS CBC IV attack, also called the BEAST attack.

Louis Francis Cristillo (March 6, 1906 – March 3, 1959), professionally known as Lou Costello, was an American actor, best known for his film comedy double act with straight man Bud Abbott and their comedy routine "Who's on First?"

Louis Francis Cristillo, bekannt als Lou Costello (* 6. März 1906 in Paterson, New Jersey, USA; † 3. März 1959 in Los Angeles, Kalifornien, USA), war ein US-amerikanischer Schauspieler, Produzent und Komiker. Zusammen mit Bud Abbott war er das populäre Komiker-Duo Abbott und Costello, in dem Abbott als Stichwortgeber für Costello fungierte. Letztlich in Nachfolge von Stan Laurel und Oliver Hardy waren die beiden das wohl erfolgreichste US-amerikanische Komiker-Duo der 1940er Jahre und hielten ihre Popularität bis weit in die 1950er Jahre hinein aufrecht.


Basic definition.

The most common definition of elliptic coordinates formula_6 is  where formula_9 is a nonnegative real number and formula_10  On the complex plane, an equivalent relationship is  These definitions correspond to ellipses and hyperbolae. The trigonometric identity  shows that curves of constant formula_9 form ellipses, whereas the hyperbolic trigonometric identity  shows that curves of constant formula_15 form hyperbolae.

Scale factors.

In an orthogonal coordinate system the lengths of the basis vectors are known as scale factors. The scale factors for the elliptic coordinates formula_6 are equal to  Using the "double argument identities" for hyperbolic functions and trigonometric functions, the scale factors can be equivalently expressed as  Consequently, an infinitesimal element of area equals  and the Laplacian reads  Other differential operators such as formula_21 and formula_22 can be expressed in the coordinates formula_6 by substituting the scale factors into the general formulae found in orthogonal coordinates.

Alternative definition.

An alternative and geometrically intuitive set of elliptic coordinates formula_24 are sometimes used, where formula_25 and formula_26. Hence, the curves of constant formula_27 are ellipses, whereas the curves of constant formula_28 are hyperbolae. The coordinate formula_28 must belong to the interval [-1, 1], whereas the formula_27 coordinate must be greater than or equal to one. The coordinates formula_24 have a simple relation to the distances to the foci formula_1 and formula_2. For any point in the plane, the "sum" formula_34 of its distances to the foci equals formula_35, whereas their "difference" formula_36 equals formula_37. Thus, the distance to formula_1 is formula_39, whereas the distance to formula_2 is formula_41. (Recall that formula_1 and formula_2 are located at formula_44 and formula_45, respectively.)  A drawback of these coordinates is that the points with Cartesian coordinates (x,y) and (x,-y) have the same coordinates formula_24, so the conversion to Cartesian coordinates is not a function, but a multifunction.

Alternative scale factors.

The scale factors for the alternative elliptic coordinates formula_24 are  Hence, the infinitesimal area element becomes  and the Laplacian equals  Other differential operators such as formula_21 and formula_22 can be expressed in the coordinates formula_24 by substituting the scale factors into the general formulae found in orthogonal coordinates.

Extrapolation to higher dimensions.

Elliptic coordinates form the basis for several sets of three-dimensional orthogonal coordinates. The elliptic cylindrical coordinates are produced by projecting in the formula_57-direction. The prolate spheroidal coordinates are produced by rotating the elliptic coordinates about the formula_5-axis, i.e., the axis connecting the foci, whereas the oblate spheroidal coordinates are produced by rotating the elliptic coordinates about the formula_59-axis, i.e., the axis separating the foci.

Applications.

The classic applications of elliptic coordinates are in solving partial differential equations, e.g., Laplace's equation or the Helmholtz equation, for which elliptic coordinates are a natural description of a system thus allowing a separation of variables in the partial differential equations. Some traditional examples are solving systems such as electrons orbiting a molecule or planetary orbits that have an elliptical shape.  The geometric properties of elliptic coordinates can also be useful. A typical example might involve an integration over all pairs of vectors formula_60 and formula_61 that sum to a fixed vector formula_62, where the integrand was a function of the vector lengths formula_63 and formula_64. (In such a case, one would position formula_65 between the two foci and aligned with the formula_5-axis, i.e., formula_67.) For concreteness, formula_65, formula_60 and formula_61 could represent the momenta of a particle and its decomposition products, respectively, and the integrand might involve the kinetic energies of the products (which are proportional to the squared lengths of the momenta).

In geometry, the elliptic coordinate system is a two-dimensional orthogonal coordinate system in which the coordinate lines are confocal ellipses and hyperbolae. The two foci formula_1 and formula_2 are generally taken to be fixed at formula_3 and formula_4, respectively, on the formula_5-axis of the Cartesian coordinate system.

In einem elliptischen Koordinatensystem wird ein Punkt der Ebene durch Angabe der Lage auf konfokalen Ellipsen und Hyperbeln bestimmt. Allgemeiner existieren auch elliptische Koordinatensysteme im dreidimensionalen Raum.