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The Journal of Electroceramics is a peer-reviewed scientific journal that was established in 1997. It is published by Springer Science+Business Media on behalf of The Minerals, Metals & Materials Society . The editor-in-chief is Harry L. Tuller .
This journal covers research on electrical, optical, and magnetic ceramics , including silicon-electroceramic integration, nanotechnology , ceramic - polymer composites, grain boundary and defect engineering. Invited papers occasionally appear in the journal which provide information that encompasses significant progress and analysis of future trends in the various interdisciplinary sub-fields.
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 1.785. [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_Electroceramics |
The Journal of Electronic Materials is a monthly peer-reviewed scientific journal that publishes studies, research, developments, and applications of materials that produce electronics . The editor-in-chief is Shadi Shahedipour-Sandvik, SUNY Polytechnic Institute.The IEEE/TMS Journal of Electronic Materials (JEM) is jointly sponsored by the IEEE Electron Devices Society and The Minerals, Metals and Materials Society. It is published by Springer on behalf of IEEE and TMS.
The journal also investigates the latest uses for semiconductors , magnetic alloys , dielectrics , nanoscale materials, and photonic materials. It also publishes methodologies for investigating the chemical properties , physical properties , and the electronic , and optical properties of these materials . Also, the specific materials science involves transistors , nanotechnology , electronic packaging , detectors, emitters , metallization , superconductivity , and energy applications.
Publishing formats include review papers and selected conference papers . Specialists and non-specialists, interested in this journal's topical coverage, are the target audience . [ 1 ] [ 2 ]
According to the Journal Citation Reports , the Journal of Electronic Materials has a 2020 impact factor of 1.938.
The following databases provide indexing and abstracting services : [ 3 ] | https://en.wikipedia.org/wiki/Journal_of_Electronic_Materials |
The Journal of Environmental Biology is a bimonthly peer-reviewed scientific journal published by Triveni Enterprises. It covers all aspects of environmental sciences , toxicology , and related fields. The editor-in-chief is R.C. Dalela, who started the journal in 1980.
Print-issues are published bimonthly (January, March, May, July, September, November) and almost immediately after that, the contents are also published online with free access.
According to the Journal Citation Reports , the journal has a 2011 impact factor of 0.640, ranking it 180th out of 205 journals in the category "Environmental Sciences". [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_Environmental_Biology |
The Journal of Environmental Engineering is a monthly engineering journal published by the American Society of Civil Engineers . [ 1 ]
The main editor is Dionysios D. Dionysiou of University of Cincinnati .
The journal presents broad interdisciplinary information on the practice and status of research in environmental engineering science, systems engineering, and sanitation. [ 2 ] Papers focus on engineering methods; impacts of wastewater collection and treatment; watershed contamination; environmental biology ; nonpoint-source pollution on watersheds; air pollution and acid deposition; and solid waste management .
As one of ASCE's flagship journals which began publication in 1956, this journal's origin goes back to the publication of the first volume of Transactions of the American Society of Civil Engineers in 1892. [ 3 ] Established originally as Journal of the Sanitary Engineering Division and renamed Journal of the Environmental Engineering Division in 1973, it acquired its current name in 1983.
The journal is indexed in Google Scholar , Baidu, Elsevier (Ei Compendex), Clarivate Analytics (Web of Science), ProQuest, Civil engineering database , TRDI, OCLC (WorldCat), [ 4 ] IET/INSPEC, Crossref, Scopus , [ 5 ] and EBSCOHost. | https://en.wikipedia.org/wiki/Journal_of_Environmental_Engineering |
The Journal of Environmental Management is a semi-monthly peer-reviewed scientific journal covering research on environmental science and quality that was established in 1973 by Academic Press in London. It is currently published by Elsevier and the editors-in-chief are Raf Dewil ( KU Leuven ), Jason Evans ( Stetson University ), and Lixiao Zhang ( Beijing Normal University ). [ 1 ]
The journal absorbed Advances in Environmental Research which was published between 1997 and 2004. [ 2 ] The open access journal Environmental Challenges , published since 2020, is a companion journal . [ 3 ]
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2021 impact factor of 8.910, ranking it 34th out of 279 journals in the category "Environmental Sciences". [ 13 ] | https://en.wikipedia.org/wiki/Journal_of_Environmental_Management |
The Journal of Environmental Quality is a bimonthly peer-reviewed scientific journal publishing original research in the area of anthropogenic impacts on the environment, including terrestrial , atmospheric and aquatic systems. According to Journal Citation Reports , the journal has a 2020 impact factor of 2.751. [ 1 ] It was established in 1972 as the first joint publication of the not-for-profit American Society of Agronomy , Crop Science Society of America , and Soil Science Society of America . The journal is currently published by the three societies in partnership with Wiley. The journal was a quarterly publication for the period of 1972 to 1993. Since 1994 it has been a bimonthly publication journal. Since 2013, it is available online only.
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Journal of Environmental Radioactivity is a monthly peer-reviewed scientific journal on environmental radioactivity and radioecology . It was proposed and started by Founding Editor Murdoch Baxter in 1984 and is published by Elsevier . Its current editor-in-chief is Stephen C. Sheppard (ECOMatters Inc.) and is an affiliated journal of the International Union of Radioecology .
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 2.674. [ 5 ]
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The Journal of Enzyme Inhibition and Medicinal Chemistry is a peer-reviewed open access medical journal published by Taylor & Francis that covers research on enzyme inhibitors and inhibitory processes as well as agonist/antagonist receptor interactions in the development of medicinal and anti-cancer agents. The editor-in-chief is Claudiu T. Supuran.
The Journal of Enzyme Inhibition and Medicinal Chemistry is abstracted and indexed in:
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The Journal of Ethnobiology is a quarterly peer-reviewed academic journal covering ethnobiology . Founded in 1981, JoE is the oldest ethnobiological journal in the world. JoE is an interdisciplinary and transdisciplinary journal publishing work from across the biological sciences, ecological sciences, humanities and social sciences that explores human engagement with, and knowledge of, biophysical environments across space and time.
The journal publishes high-quality and high-impact research in the field of ethnobiology s ensu lato . Work published in the journal demonstrates how an ethnobiological perspective can not only inform other related disciplines but also policy and practice for biocultural conservation.
The editor-in-chief is John Richard Stepp . According to the Journal Citation Reports , it has a 2022 impact factor of 2.9, making it the 7th (out of 92) highest ranked journal in the field of Anthropology, and in the top third of all Biology journals.
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The Journal of Experimental Marine Biology and Ecology is a peer-reviewed bimonthly journal which publishes work on the biochemistry, physiology, behaviour, and genetics of marine plants and animals in relation to their ecology. According to the Journal Citation Reports , the journal has a 2015 impact factor of 1.796. [ 1 ]
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The Journal of Fire Sciences is a bimonthly peer-reviewed scientific journal that covers the fields of engineering and materials science as applied to fire prevention . The editor-in-chief is Alexander B. Morgan. It was established in 1983 and is published by SAGE Publications .
The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded . According to the Journal Citation Reports , its 2020 impact factor is 1.694, ranking it 57th out of 91 journals in the category "Engineering, Multidisciplinary" [ 1 ] and 269th out of 334 journals in the category "Materials Science, Multidisciplinary". [ 2 ] | https://en.wikipedia.org/wiki/Journal_of_Fire_Sciences |
The Journal of Formalized Reasoning is a peer-reviewed open access academic journal established in 2009. It publishes formalization efforts in any area, including classical mathematics, constructive mathematics , formal algorithms , and program verifications . It is maintained by AlmaDL , the digital library of the University of Bologna .
The journal is abstracted and indexed in Scopus , MathSciNet , and Zentralblatt MATH .
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Journal of Functional Biomaterials is a peer-reviewed open-access scientific journal covering various aspects of biomaterials research. It is published by MDPI and was established in 2012. The editor-in-chief is Pankaj Vadgama ( Queen Mary University of London ). [ 1 ]
The journal publishes research articles, reviews, and commentaries related to research, including nanomedicine , nanotechnology , and sensors for health.
The journal is abstracted and indexed, for example, in: [ 2 ]
According to the Journal Citation Reports , the journal has a 2022 impact factor of 4.8. [ 3 ] | https://en.wikipedia.org/wiki/Journal_of_Functional_Biomaterials |
The Journal of Geometry is a triannual peer-reviewed scientific journal covering geometry , broadly considered. In particular this includes "foundations of geometry, geometric algebra, finite geometries, combinatorial geometry, and special geometries". [ 1 ] It was established in 1971 by Walter Benz [ 2 ] and is published by Birkhäuser . [ 1 ] The editors-in-chief are Hans Havlicek ( Technische Universität Wien ) and Alexander Kreuzer ( Universität Hamburg ). [ 3 ]
The journal is abstracted and indexed in EBSCO databases , [ 4 ] Emerging Sources Citation Index , [ 5 ] Scopus , [ 6 ] and zbMATH Open . [ 7 ] | https://en.wikipedia.org/wiki/Journal_of_Geometry |
The Journal of Geometry and Physics is a scientific journal in mathematical physics . Its scope is to stimulate the interaction between geometry and physics by publishing primary research and review articles which are of common interest to practitioners in both fields. The journal is published by Elsevier since 1984.
The Journal covers the following areas of research:
Methods of:
Applications to:
The editor-in-chief is G. Landi ( Università di Trieste ).
The Advisory Editor is U. Bruzzo.
The Editors are L. Jeffrey, V. Mathai and V. Rubtsov.
This journal is indexed by the following services: | https://en.wikipedia.org/wiki/Journal_of_Geometry_and_Physics |
The Journal of Green Building is a quarterly peer-reviewed academic journal covering research on green buildings , applications, techniques, and processes. It was established in 2006 and the editor-in-chief is Steffen Lehmann ( University of South Australia ). The journal is abstracted and indexed in the Arts & Humanities Citation Index and Current Contents /Arts & Humanities. [ 1 ]
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The Journal of Group Theory is a bimonthly peer-reviewed mathematical journal covering all aspects of group theory . It was established in 1998 and is published by Walter de Gruyter . The editor-in-chief is Chris Parker ( University of Birmingham ).
The journal is abstracted and indexed in:
Its 2018 MCQ is 0.48. [ 1 ] According to the Journal Citation Reports , the journal has a 2018 impact factor of 0.47, and the 5-year impact factor is 0.52. [ 2 ] | https://en.wikipedia.org/wiki/Journal_of_Group_Theory |
The Journal of Hazardous Materials is a peer-reviewed , scientific journal that covers the study of hazardous materials and their impact on the environment. The journal is published by Elsevier and was established in 1975. [ 1 ] Since 2022, the editor-in-chief is Zhen He ( Washington University in St. Louis ). [ 2 ] The journal publishes original research articles , review articles , and short communications.
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2021 impact factor of 14.224. [ 12 ] | https://en.wikipedia.org/wiki/Journal_of_Hazardous_Materials |
The Journal of Industrial Ecology is a bimonthly peer-reviewed academic journal covering industrial ecology . It is published by Wiley-Blackwell on behalf of the Yale School of the Environment [ 1 ] and is an official journal of the International Society for Industrial Ecology . [ 2 ] The editor-in-chief is Reid Lifset. According to the Journal Citation Reports , the journal had an impact factor of 6.946 in 2020. [ 3 ]
The journal is abstracted and indexed in: [ citation needed ]
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The Journal of Industrial Textiles is a peer-reviewed scientific journal that covers materials science as applied to textiles . Its editor-in-chief is Dong Zhang . It was established in 1971 and is published by SAGE Publications .
The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded . According to the Journal Citation Reports , its 2020 impact factor is 3.732, ranking it 4th out of 25 journals in the category "Materials Science, Textiles". [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_Industrial_Textiles |
The Journal of Inorganic Biochemistry is a monthly peer-reviewed scientific journal covering research on the inorganic aspects of biochemistry , such as metalloenzymes and metallobiomolecules . The journal was established in 1971 as Bioinorganic Chemistry , obtaining its current name in 1979. Since 1996, the editor-in-chief has been John H. Dawson ( University of South Carolina ). [ 1 ]
According to the Journal Citation Reports , the journal has a 2020 impact factor of 4.155, ranking it 7th out of 44 journals in the category "Chemistry, Inorganic and Nuclear". [ 2 ]
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The Journal of Materials Chemistry was a weekly peer-reviewed scientific journal covering the applications, properties and synthesis of new materials. It was established in 1991 and published by the Royal Society of Chemistry . At the end of 2012 the journal was split into three independent journals: Journal of Materials Chemistry A (energy and sustainability), Journal of Materials Chemistry B (biology and medicine) and Journal of Materials Chemistry C (optical, magnetic and electronic devices). [ 1 ] The editor-in-chief was Liz Dunn.
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The Journal of Materials Chemistry A is a weekly peer-reviewed scientific journal that covers the synthesis, properties, and applications of novel materials related to energy and sustainability. It is one of three journals created after the Journal of Materials Chemistry was split at the end of 2012. Its first issue was published in January 2013. [ 1 ] The journal is published by the Royal Society of Chemistry and has two sister journals, Journal of Materials Chemistry B and Journal of Materials Chemistry C , which cover different materials science topics. The editor-in-chief for the Journal of Materials Chemistry family of journals is currently Nazario Martin. The deputy editor-in-chief for Journal of Materials Chemistry A is Anders Hagfeldt , [ 2 ] while the executive editor is Michaela Mühlberg. [ 3 ]
The journal is abstracted and indexed in the Science Citation Index Expanded , Current Contents /Physical, Chemical & Earth Sciences, and Current Contents/Engineering, Computing & Technology. [ 4 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Chemistry_A |
The Journal of Materials Chemistry B is a weekly peer-reviewed scientific journal covering the properties, applications, and synthesis of new materials related to biology and medicine . It is one of the three journals that were created after the Journal of Materials Chemistry was split at the end of 2012. The first issue was published in January 2013. [ 1 ] It is published by the Royal Society of Chemistry . The other two parts of the Journal of Materials Chemistry family are Journal of Materials Chemistry A and Journal of Materials Chemistry C , which cover different materials science topics. The editor-in-chief for the Journal of Materials Chemistry family of journals is currently Nazario Martin. The current editor-in-chief for Journal of Materials Chemistry B is Jessica Winter. [ 2 ]
The journal is abstracted and indexed in the Science Citation Index . [ 3 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Chemistry_B |
The Journal of Materials Chemistry C is a weekly peer-reviewed scientific journal covering the properties, applications, and synthesis of new materials related to optical , magnetic and electronic devices. It is one of the three journals created from the splitting of Journal of Materials Chemistry at the end of 2012. Its first issue was published in January 2013. [ 1 ] The journal is published by the Royal Society of Chemistry and has two sister journals, Journal of Materials Chemistry A and Journal of Materials Chemistry B . The editor-in-chief for the Journal of Materials Chemistry family of journals is currently Nazario Martin. The deputy editor-in-chief for Journal of Materials Chemistry C is Natalie Stingelin . [ 2 ]
The journal is abstracted and indexed in the Science Citation Index . [ 3 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Chemistry_C |
The Journal of Materials Engineering and Performance is a monthly peer-reviewed scientific journal published by Springer Science+Business Media on behalf of ASM International . The editor-in-chief is Rajiv Asthana ( University of Wisconsin ). The journal covers all aspects of materials engineering broadly described as materials selection, design, processing, characterization, and evaluation. The scope includes all substances used in engineering applications with a tendency toward constituent materials that comprise a larger system.
This journal is abstracted and indexed by:
According to the Journal Citation Reports , the journal has a 2021 impact factor of 1.819. [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Engineering_and_Performance |
Journal of Materials Processing Technology is a peer-reviewed scientific journal covering research on all aspects of processing techniques used in manufacturing components from various materials. It is published by Elsevier and the editor-in-chief is J. Cao ( Northwestern University ). [ 1 ]
The journal is abstracted and indexed in Scopus , Science Citation Index Expanded , Metadex , and Inspec . The journal has a 2021 impact factor of 6.162. [ 2 ]
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The Journal of Materials Research and Technology is a quarterly peer-reviewed open access scientific journal covering metallurgy and materials and minerals research and technology. It is published by Elsevier on behalf of the Brazilian Metallurgical, Materials and Mining Association . The editor-in-chief is Marc A. Meyers ( University of California, San Diego ).
The journal is abstracted and indexed in Scopus . [ 1 ]
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The Journal of Materials Science is a weekly peer-reviewed scientific journal covering all aspects of materials science . It was established in 1966 by Robert W. Cahn and is published by Springer Science+Business Media . The journal incorporated Journal of Materials Science Letters in 2003 and Interface Science in 2004. The Editor-in-Chief is C. Barry Carter ( University of Connecticut ).
In 2012, the journal announced an annual "Cahn Prize" for best paper published in the journal, in honor of its founding editor. [ 1 ] In 2021, the journal announced a similar annual "Bonfield Prize" for best review paper published in the journal, in honor of a former Editor-in-Chief, William Bonfield . [ 2 ] There are two more specialized sister journals, Journal of Materials Science: Materials in Medicine and Journal of Materials Science: Materials in Electronics .
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 4.220, ranking it 82nd out of 293 journals in the category "Materials Science, Multidisciplinary". [ 7 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Science |
The Journal of Materials Science: Materials in Electronics is a peer-reviewed scientific journal published by Springer Science+Business Media . It is an offshoot of the Journal of Materials Science , focusing specifically on materials used in electronics . The editor-in-chief is Safa Kasap ( University of Saskatchewan , Canada).
This journal was originally published quarterly by Chapman & Hall from May 1990. This frequency was changed to six issues per year from 1994 to 1998, and then nine issues per year from 1999 to 2000. From 2001, the journal has been published monthly. [ 1 ] [ 2 ]
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 2.478. [ 3 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Science:_Materials_in_Electronics |
The Journal of Materials Science: Materials in Medicine is a peer-reviewed scientific journal published by Springer Science+Business Media . It is an offshoot of the Journal of Materials Science , focusing specifically on materials in medicine and dentistry. The founding editor in chief was William Bonfield; the current editor-in-chief is Luigi Ambrosio (National Research Council (CNR) Naples, Italy).
According to the Journal Citation Reports , the Journal of Materials Science: Materials in Medicine has a 2020 impact factor of 3.896. [ 1 ]
The journal's content focusses on the development of synthetic and natural materials for orthopaedic, maxillofacial, cardiovascular, neurological, ophthalmic and dental applications. Further, biocompatibility studies, nanomedicine , studies on regenerative medicine , computer modelling , and other advanced experimental methodologies are included. [ 2 ] | https://en.wikipedia.org/wiki/Journal_of_Materials_Science:_Materials_in_Medicine |
The Journal of Materials in Civil Engineering is a monthly peer-reviewed scientific journal established in 1989 by the American Society of Civil Engineers . It covers research and best practices concerns on development, processing, evaluation, applications, and performance of construction materials in civil engineering . It consists of four sections: cementitious material, asphalt , geo-materials, and hybrids (which encompass steel , timber , masonry , and composite materials ).
The journal is abstracted and indexed in Ei Compendex , ProQuest databases , Civil engineering database , Inspec , Scopus , [ 1 ] and EBSCO databases . | https://en.wikipedia.org/wiki/Journal_of_Materials_in_Civil_Engineering |
The Journal of Mathematical Analysis and Applications is an academic journal in mathematics, specializing in mathematical analysis and related topics in applied mathematics . It was founded in 1960 by Richard Bellman , [ 1 ] as part of a series of new journals on areas of mathematics published by Academic Press , [ 2 ] and is now published by Elsevier . For most years since 2003 it has been ranked by SCImago Journal Rank as among the top 25% of journals in its topic areas. [ 3 ]
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The Journal of Mathematical Physics, Analysis, Geometry is a quarterly peer-reviewed scientific journal covering mathematics as applied to physics . It is published by the Verkin Institute for Low Temperature Physics and Engineering and was established in 1994 as Mathematical Physics, Analysis, Geometry . Papers are published in English, Ukrainian, and Russian. The journal is abstracted and indexed by Scopus . According to the Journal Citation Reports , the journal has a 2017 impact factor of 0.531. [ 1 ]
The following persons are or have been editors-in-chief :
The Kharkov Mathematical Society was founded in 1879 and, starting in 1880, the society published the journal named Communications of the Kharkov Mathematical Society (Russian Сообщения и протоколы заседаний математического общества при Императорском Харьковском университете ). Publication was suspended in 1960, but in 1965 due to the efforts of Naum Akhiezer the journals Theory of functions, functional analysis and their applications , and Ukrainian Geometric Collection» were established. In 1994, these journals were merged by the Mathematical Division of the Verkin Institute to establish the current journal. The first editor was Vladimir Marchenko . [ 2 ] | https://en.wikipedia.org/wiki/Journal_of_Mathematical_Physics,_Analysis,_Geometry |
The Journal of Mechanics of Materials and Structures is a peer-reviewed scientific journal covering research on the mechanics of materials and deformable structures of all types. It was established by Charles R. Steele , who was also the first editor-in-chief .
The journal was established in 2006 after 21 of the 23 members of the editorial board of the International Journal of Solids and Structures resigned in protest of Elsevier 's "pressure for increased profits out of the limited institutional resources." [ 1 ] [ 2 ] In their founding issue, the editors of the new journal indicated several desires for the publication, including, "a low subscription price that will not grow faster than the number of pages and indeed may drop as the subscriber base expands." [ 3 ]
The journal is abstracted and indexed in Current Contents /Engineering, Computing & Technology, [ 4 ] Ei Compendex , [ 5 ] Science Citation Index Expanded , [ 4 ] and Scopus . [ 6 ] According to the Journal Citation Reports , the journal has a 2020 impact factor of 0.987. [ 7 ]
Official website | https://en.wikipedia.org/wiki/Journal_of_Mechanics_of_Materials_and_Structures |
The Journal of Medicinal Chemistry is a biweekly peer-reviewed medical journal covering research in medicinal chemistry . It is published by the American Chemical Society . It was established in 1959 as the Journal of Medicinal and Pharmaceutical Chemistry and obtained its current name in 1963. [ 1 ] Philip S. Portoghese served as editor-in-chief from 1972 to 2011. [ 1 ] In 2012, Gunda Georg ( University of Minnesota ) and Shaomeng Wang ( University of Michigan ) succeeded Portoghese ( University of Minnesota ). In 2021, Craig W. Lindsley ( Vanderbilt University ) became editor-in-chief. According to the Journal Citation Reports , the journal has a 2023 impact factor of 7.1. [ 2 ]
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Journal of Micro/Nanopatterning, Materials, and Metrology is a peer-reviewed scientific journal published quarterly by SPIE . It covers science, development, and practice of micro and nanofabrication processes and metrology . [ 1 ] Established in 2002 under the name Journal of Microlithography, Microfabrication, and Microsystems , it was subsequently retitled to Journal of Micro/Nanolithography, MEMS, and MOEMS in 2007. The journal title was changed to its current name in 2021. [ 2 ]
The editor-in-chief of the journal is Harry Levinson (HJL Lithography). [ 1 ]
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2023 impact factor of 3.4. [ 8 ] | https://en.wikipedia.org/wiki/Journal_of_Micro/Nanopatterning,_Materials,_and_Metrology |
Journal of Microelectromechanical Systems is a peer-reviewed scientific journal published bimonthly by IEEE . It covers advances in MEMS and related microtechnologies . Published under the joint sponsorship of IEEE Electron Devices Society, IEEE Industrial Electronics Society, and IEEE Robotics and Automation Society, its editor-in-chief is Gianluca Piazza ( Carnegie Mellon University ). [ 1 ] [ 2 ]
According to the Journal Citation Reports , the journal has a 2022 impact factor of 2.7. [ 3 ]
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The Journal of Microscopy is the monthly peer-reviewed scientific journal of the Royal Microscopical Society which covers all aspects of microscopy including spatially resolved spectroscopy , compositional mapping, and image analysis . This includes technology and applications in physics , chemistry , material science , and the life sciences. It is published by Wiley-Blackwell on behalf of the Society. The editor-in-chief is Michelle Peckham, a Cell Biology professor at University of Leeds . The journal publishes review articles , original research papers, short communications, and letters to the editor . It was established in 1841 as the Transactions of the Microscopical Society of London , obtaining its current name in 1869, with volume numbering restarting at 1. [ 1 ] [ clarification needed ]
The journals is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 1.758. [ 2 ]
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The Journal of Mining and Metallurgy, Section B: Metallurgy is a biannual peer-reviewed scientific journal that covers mining and metallurgy . The editor-in-chief is Dragana Živković ( University of Belgrade ). Publishing formats include original research articles, review articles, short notices, letters, and book reviews .
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2012 impact factor of 1.435, ranking it 12th out of 75 journals in the category "Metallurgy & Metallurgical Engineering". [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_Mining_and_Metallurgy,_Section_B |
Journal of Molecular Structure is a scientific journal published by Elsevier through ScienceDirect since 1968. It specializes in research on the structural properties of molecules, emphasizing experimental and computational studies in fields like chemistry , physics , and materials science .
The journal publishes work on a wide array of topics, including molecular spectroscopy, crystallography, and molecular modeling. It serves as a platform for advancements in structural analysis techniques, such as X-ray diffraction, nuclear magnetic resonance (NMR), and vibrational spectroscopy, contributing to a deeper understanding of molecular systems and interactions.
The journal operates under a peer-review system, ensuring the quality and significance of its published research. It offers both subscription-based and open-access publishing options, making it accessible to a broad scientific audience. Researchers value the journal for its comprehensive coverage and rigorous editorial standards.
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Journal of Nanophotonics is a quartertly peer-reviewed scientific journal published by SPIE . It covers theoretical, computational and experimental aspects of nanophotonics and their applications. It began publication in 2007 with Akhlesh Lakhtakia of Pennsylvania State University as its editor-in-chief. In 2013, Ali Adibi of Georgia Institute of Technology became its second editor-in-chief. [ 1 ]
According to the Journal Citation Reports , the journal has a 2023 impact factor of 1.1. [ 2 ]
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The Journal of Non-Equilibrium Thermodynamics is a quarterly peer-reviewed scientific journal covering the field of non-equilibrium thermodynamics . It was established in 1976 by Jurgen Keller and its current editor-in-chief is Karl-Heinz Hoffmann ( Chemnitz University of Technology ).
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2021 impact factor of 4.290. [ 1 ]
Official website
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The Journal of Nonlinear Optical Physics & Materials is a quarterly peer-reviewed scientific journal that was established in 1992 and is published by World Scientific . It covers developments in the field of nonlinear interactions of light with matter , guided waves , and solitons , as well as their applications, such as in laser and coherent lightwave amplification, and information processing. [ 1 ]
The journal is abstracted and indexed in:
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The Journal of Nuclear Materials is a monthly peer-reviewed scientific journal on materials research for accelerator physics , nuclear power generation and fuel cycle applications. It was established in 1959 and is published by Elsevier . The current editor-in-chief is Gary S. Was ( University of Michigan ).
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 2.936. [ 5 ]
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The Journal of Number Theory ( JNT ) is a monthly peer-reviewed scientific journal covering all aspects of number theory . The journal was established in 1969 by R.P. Bambah, P. Roquette, A. Ross , A. Woods, and H. Zassenhaus ( Ohio State University ). It is currently published monthly by Elsevier and the editor-in-chief is Dorian Goldfeld ( Columbia University ). According to the Journal Citation Reports , the journal has a 2022 impact factor of 0.7. [ 1 ]
The David Goss Prize in Number theory, founded by the Journal of Number Theory, is awarded every two years, to mathematicians under the age of 35 for outstanding contributions to number theory. The prize is dedicated to the memory of David Goss who was the former editor in chief of the Journal of Number Theory. The current award is 10,000 USD.
The winners are selected and chosen by the scientific organizing committee of the JNT Biennial Conference and announced during the JNT Biennial Conference.
JNT 2019 Biennial: https://www.math.columbia.edu/~goldfeld/JNTBiennial2019.html
JNT 2022 Biennial: https://www.math.columbia.edu/~goldfeld/JNTBiennial2022.html
JNT 2024 Biennial: https://www.math.columbia.edu/~goldfeld/JNTBiennial2024.html
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The Journal of Organometallic Chemistry is a peer-reviewed scientific journal published by Elsevier , covering research on organometallic chemistry . According to the Journal Citation Reports , the journal has a 2021 impact factor of 2.345. [ 1 ]
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The Journal of Photochemistry and Photobiology is a series of peer-reviewed scientific journals covering the fields of photochemistry and photobiology , published by Elsevier . It was originally established in 1972, and split into Journal of Photochemistry and Photobiology A: Chemistry and Journal of Photochemistry and Photobiology B: Biology in 1987. A third title; Journal of Photochemistry and Photobiology C: Photochemistry Reviews , was established in 2000 and is the official journal of the Japanese Photochemistry Association .
The Journal of Photochemistry was established in 1972 under founding editor-in-chief Richard P. Wayne . [ 1 ] Originally published quarterly, by 1987 frequency had increased to monthly. [ 2 ]
In 1986, the 38th Council of the American Society for Photobiology (ASP) established a committee to investigate the proposal that the European Society for Photobiology (ESP) share the operation of the ASP official journal, Photochemistry and Photobiology . In 1987, financial and contractual problems prevented agreement and, instead, ESP contracted with Elsevier , [ 3 ] leading to the restructuring of the Journal of Photochemistry into two separate journals: the Journal of Photochemistry and Photobiology A: Chemistry , [ 4 ] continuing under Richard P. Wayne [ 5 ] and covering photochemistry and the Journal of Photochemistry and Photobiology B: Biology [ 6 ] under founding editor Giulio Jori , [ 7 ] covering photobiology.
The Journal of Photochemistry and Photobiology C: Photochemistry Reviews was first published in 2000 [ 8 ] with Akira Fujishima as founding editor-in-chief. When the journal was first established, it aimed to increase from two issues a year to four, [ 9 ] an objective achieved and maintained since 2003. [ 8 ]
The Journal of Photochemistry and Photobiology A: Chemistry is published biweekly. There is no editor-in-chief; editorial responsibility is shared and divided geographically with Hiroshi Masuhara covering Asia, Russ Schmehl covering America, and Monique Martin covering Europe. [ 5 ]
The Journal of Photochemistry and Photobiology A: Chemistry is abstracted and indexed in BIOSIS Previews , Chemical Abstracts , Chemical Citation Index , Current Contents /Physics, Chemistry & Engineering, Engineering Index , Metals Abstracts , PASCAL , Physics Abstracts , Physikalische Berichte , Polymer Contents , Science Citation Index and Scopus . According to the Journal Citation Reports , the journal has a 2019 impact factor of 3.261. [ 10 ]
The Journal of Photochemistry and Photobiology B: Biology is published monthly. The editors are Robert Carpentier and Dominic J. Robinson . Carpentier covers the fields of biophysics , biomolecular spectroscopy , photosynthesis , environmental photobiology, oxygen radicals , DNA repair , and UV- /VIS effects. Robinson covers photomedicine , photodynamic therapy , photosensitisers and dermatology . [ 7 ]
The Journal of Photochemistry and Photobiology B: Biology is abstracted and indexed in BIOSIS , Cambridge Scientific Abstracts , Chemical Abstracts, Current Contents, BIOBASE /Current Awareness in Biological Sciences, EMBASE , Embiology , Engineering Index, Metals Abstracts, PASCAL, Physics Abstracts, Physikalische Berichte, Polymer Contents, Science Citation Index, and Scopus. According to the Journal Citation Reports , the journal has a 2016 impact factor of 2.673. [ 11 ]
Journal of Photochemistry and Photobiology C: Photochemistry Reviews focusses on photochemistry literature reviews . It is the official journal of the Japanese Photochemistry Association and is published quarterly. The editor-in-chief is Hiroaki Misawa .
The Journal of Photochemistry and Photobiology C: Photochemistry Reviews is abstracted and indexed in BIOSIS Previews, Chemistry & Chemical Engineering , Chemistry Citation Index, Current Contents/Physical, Chemical & Earth Sciences, Science Citation Index and Scopus. According to the Journal Citation Reports , the journal has a 2014 impact factor of 16.094. [ 12 ] | https://en.wikipedia.org/wiki/Journal_of_Photochemistry_and_Photobiology |
The Journal of Physical Organic Chemistry is a monthly peer-reviewed scientific journal , published since 1988 by John Wiley & Sons . It covers research in physical organic chemistry in its broadest sense and is available both online and in print. The current editor-in-chief is Rik Tykwinski ( University of Alberta ). [ 1 ]
According to Web of Science the three most cited papers in the journal are: [ 2 ]
The journal is indexed in Chemical Abstracts Service , Scopus , and Web of Science . According to the Journal Citation Reports , the journal has a 2021 impact factor of 2.155. [ 3 ]
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Journal of Physics and Chemistry of Solids is a peer-reviewed scientific journal of condensed matter physics and material science . The journal is edited by M. Azuma, A. Bansil, H.-P. Cheng, and K. Prassides. The journal was established in 1957 by Harvey Brooks , [ 1 ] and is published monthly by Elsevier .
In 1963 the Letters section of the journal split to form Solid State Communications .
The journal is abstracted and indexed in the following databases: | https://en.wikipedia.org/wiki/Journal_of_Physics_and_Chemistry_of_Solids |
The Journal of Plastic Film and Sheeting is a peer-reviewed scientific journal that covers the field of materials science , especially the development and processing of plastic film and sheeting. The editors-in-chief are John R. Wagner Jr. and James P. Harrington. It was established in 1985 and is published by SAGE Publications .
The journal is abstracted and indexed in Scopus , and the Science Citation Index Expanded . According to the Journal Citation Reports , its 2020 impact factor is 2.750, ranking it 12th out of 21 journals in the category "Materials Science, Coatings & Films". [ 1 ]
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Journal of Polymer Science is a peer-reviewed journal of polymer science currently published by John Wiley & Sons . It was originally established as the Journal of Polymer Science in 1946 by Interscience Publishers and the founding editor Herman F. Mark , but it was split in various parts in 1962. The journal has undergone re-organization several times since. In 2020, the journal will consolidate in one single publication. [ 1 ] The editor-in-chief is Joseph W Krumpfer. [ 2 ]
The coverage of biopolymers was split into a distinct journal, Biopolymers . | https://en.wikipedia.org/wiki/Journal_of_Polymer_Science |
The Journal of Pure and Applied Algebra is a monthly peer-reviewed scientific journal covering that part of algebra likely to be of general mathematical interest: algebraic results with immediate applications, and the development of algebraic theories of sufficiently general relevance to allow for future applications.
Its founding editors-in-chief were Peter J. Freyd ( University of Pennsylvania ) and Alex Heller ( City University of New York ). The current managing editors are Srikanth Iyengar ( University of Utah ), Charles Weibel ( Rutgers University ), and Aldo Conca ( Università di Genova ).
The journal is abstracted and indexed in Current Contents /Physics, Chemical, & Earth Sciences, Mathematical Reviews , PASCAL , Science Citation Index , Zentralblatt MATH , and Scopus . According to the Journal Citation Reports , the journal has a 2016 impact factor of 0.652. [ 1 ]
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The Journal of Radiation Research is a bimonthly peer-reviewed scientific journal covering research on radiation and oncology . It was established in 1960 and is published by Oxford University Press . Its editor-in-chief is Kenshi Komatsu ( University of Kyoto ).
It is an affiliated journal of the Japan Radiation Research Society and the Japanese Society for Radiation Oncology . In 1998 the journal absorbed the Japanese Society for Radiation Oncology's former title, the Journal of JASTRO . This extended the scope of the journal to include medical and oncology research.
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2019 impact factor of 2.014. 5 year Impact Factor 2.063 [ 5 ]
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The Journal of Recreational Mathematics was an American journal dedicated to recreational mathematics , started in 1968. [ 1 ] It had generally been published quarterly by the Baywood Publishing Company, until it ceased publication with the last issue (volume 38, number 2) published in 2014. The initial publisher (of volumes 1–5) was Greenwood Periodicals .
Harry L. Nelson was primary editor for five years [ 2 ] (volumes 9 through 13, excepting volume 13, number 4, when the initial editor returned as lead) and Joseph Madachy , the initial lead editor and editor of a predecessor called Recreational Mathematics Magazine which ran during the years 1961 to 1964, [ 1 ] was the editor for many years. Charles Ashbacher and Colin Singleton took over as editors when Madachy retired (volume 30 number 1). The final editors were Ashbacher and Lamarr Widmer. The journal has from its inception also listed associate editors, one of whom was Leo Moser .
The journal contains:
The journal is indexed in:
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The Journal of Reinforced Plastics and Composites is a peer-reviewed scientific journal that covers research in the field of materials science , especially plastics and composites . The editor-in-chief is G. Springer ( Stanford University ). It was established in 1982 and is currently published by SAGE Publications .
The Journal of Reinforced Plastics and Composites is abstracted and indexed in Scopus , and the Science Citation Index Expanded . According to Journal Citation Reports , its 2020 impact factor is 3.710. [ 1 ]
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The Journal of Separation Science is a biweekly peer-reviewed scientific journal covering analytical chemistry . It was established in 1978 as the Journal of High Resolution Chromatography & Chromatography Communications: HRC & CC . In 1989, it was renamed the Journal of High Resolution Chromatography . It obtained its current name in 2001, when it also absorbed the preexisting Journal of Microcolumn Separations , which had been established in 1989. It is an organ of the European Society for Separation Science and the California Separation Science Society. The editor-in-chief is František Švec ( Charles University ). According to the Journal Citation Reports , the journal has a 2020 impact factor of 3.645, ranking it 25th out of 83 journals in the category "Chemistry, Analytical". [ 1 ]
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The Journal of Solid State Chemistry is a monthly peer-reviewed scientific journal published by Elsevier . The journal covers the chemical , structural , thermodynamic , electronic , and electromagnetic characteristics and properties of solids , including ceramics and amorphous materials . The editor-in-chief is M.G. Kanatzidis ( Northwestern University ).
This journal is abstracted and indexed by:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 3.498. [ 1 ]
Official website | https://en.wikipedia.org/wiki/Journal_of_Solid_State_Chemistry |
The Journal of Strategic Information Systems is a quarterly peer-reviewed academic journal covering management , business, and organizational issues associated with the use of information systems . It was established in December 1991 by Bob Galliers, the initial editor-in-chief, and is published by Elsevier . The Co-Editors-in-Chief are Guy Gable ( Queensland University of Technology ; since 2019) and Yolande E. Chan ( Desautels Faculty of Management , McGill University ; since 2021).
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2023 impact factor of 8.7. [ 5 ] | https://en.wikipedia.org/wiki/Journal_of_Strategic_Information_Systems |
The Journal of Structural Engineering is the principal professional peer-reviewed journal of the American Society of Civil Engineers , the oldest professional civil engineering society in the United States. The journal is one of the flagship journals of the Society. It is sponsored by its division, the ASCE Structural Engineering Institute.
This journal shares knowledge and advances in the field of structural engineering . Topics that are covered include structural modeling and design; analytical, computational and experimental simulation techniques; and discuss methods for maintaining, rehabilitating monitoring existing structures, sustainable structures, resilient infrastructure, and state-of-the-art / state-of-practice content.
Originally, the journals was part of the proceedings of the American Society of Civil Engineers, first published in 1873 [ 1 ] The Journal started publishing separately in 1956 as part of the ASCE Journal of the Structural Division ( ISSN 0044-8001 ). In 1983, the title was changed to the Journal of Structural Engineering ( ISSN 0733-9445 ).
Past Editors of the Journal include:
The Journal of Structural Engineering is indexed in Scopus , [ 3 ] Web of Science , and Engineering Index , Civil engineering database , OCLC ( WorldCat ). [ 4 ] It is available on ProQuest and EbscoNet . | https://en.wikipedia.org/wiki/Journal_of_Structural_Engineering |
The Journal of Symbolic Computation is a peer-reviewed monthly scientific journal covering all aspects of symbolic computation published by Academic Press and then by Elsevier . It is targeted to both mathematicians and computer scientists . It was established in 1985 by Bruno Buchberger , who served as its editor until 1994.
The journal covers a wide variety of topics, including:
According to the Journal Citation Reports , its 2020 impact factor is 0.847. [ 2 ] The journal is abstracted and indexed by Scopus and the Science Citation Index . | https://en.wikipedia.org/wiki/Journal_of_Symbolic_Computation |
The Journal of Systems and Software is a computer science journal in the area of software systems , established in 1979 and published by Elsevier .
The journal publishes research papers , state-of-the-art surveys , and practical experience reports . It includes papers covering issues of programming methodology , software engineering , and hardware / software systems . Topics include: " software systems , prototyping issues, high-level specification techniques, procedural and functional programming techniques, data-flow concepts, multiprocessing , real-time , distributed , concurrent , and telecommunications systems, software metrics , reliability models for software, performance issues, and management concerns." [ 1 ]
According to the 2021 Journal Citation Reports , the Journal of Systems and Software has an impact factor of 3.514. [ 2 ] According to Google Scholar , the journal has an h 5-index of 61, which ranks third among international publication venues in software systems, after ICSE and IEEE Transactions on Software Engineering . [ 3 ]
A few of the most notable (downloaded) articles are: [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_Systems_and_Software |
The Journal of Thermal Analysis and Calorimetry is a bimonthly peer-reviewed scientific journal published by Springer Science+Business Media on behalf of Akadémiai Kiadó . It was established in 1969 as the Journal of Thermal Analysis , obtaining its current title in 1998. The journal covers all aspects of calorimetry , thermal analysis , and experimental thermodynamics . The editor-in-chief is I.M. Szilágyi ( Budapest University of Technology and Economics ).
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2021 impact factor of 4.755. [ 7 ] | https://en.wikipedia.org/wiki/Journal_of_Thermal_Analysis_and_Calorimetry |
The Journal of Thermal Stresses is a monthly peer-reviewed scientific journal covering the theoretical and industrial applications of thermal stresses . It is published by Taylor & Francis . The journal was established in 1978 with Richard B. Hetnarski ( Rochester Institute of Technology ) as founding editor-in-chief . In July 2018 he was succeeded by Martin Ostoja-Starzewski ( University of Illinois at Urbana-Champaign ).
The journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2020 impact factor of 3.28. [ 2 ]
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The Journal of Topology is a peer-reviewed scientific journal which publishes papers of high quality and significance in topology , geometry , and adjacent areas of mathematics. It was established in 2008, when the editorial board of Topology resigned due to the increasing costs of Elsevier 's subscriptions. [ 1 ]
The journal is owned and managed by the London Mathematical Society and produced, distributed, sold and marketed by John Wiley & Sons . It appears quarterly with articles published individually online prior to appearing in a printed issue. [ 2 ]
The journal is abstracted and indexed in Mathematical Reviews , Science Citation Index , and Zentralblatt MATH . | https://en.wikipedia.org/wiki/Journal_of_Topology |
The Journal of Trace Elements in Medicine and Biology is a bimonthly peer-reviewed medical journal covering the roles played by trace elements in medical and biological systems . It was established in 1987 as the Journal of Trace Elements and Electrolytes in Health and Disease , obtaining its current title in 1995. It is published by Elsevier on behalf of the Federation of European Societies on Trace Elements and Minerals (FESTEM), of which it is the official journal. The editor-in-chief is Dirk Schaumlöffel ( Université de Pau et des Pays de l'Adour / Centre national de la recherche scientifique ). According to the Journal Citation Reports , the journal has a 2017 impact factor of 3.755. [ 1 ]
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The Journal of Translational Medicine is a peer-reviewed open-access medical journal published by BioMed Central since 2003. The editor-in-chief is Francesco Marincola. According to the Journal Citation Reports , the journal had a 2021 impact factor of 8.440. [ 1 ]
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The Journal of the American Ceramic Society is a monthly peer-reviewed scientific journal published on behalf of the American Ceramic Society by Wiley-Blackwell . It was established in 1918 and is edited by John C. Mauro. Publishing formats include full length original research , communications (rapid publishing), feature articles, and review articles. The journal covers all aspects of research on ceramic materials science .
This journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2021 impact factor of 4.186. [ 1 ] | https://en.wikipedia.org/wiki/Journal_of_the_American_Ceramic_Society |
The Journal of the British Interplanetary Society ( JBIS ) is a monthly peer-reviewed scientific journal that was established in 1934. The journal covers research on astronautics and space science and technology , including spacecraft design, nozzle theory, launch vehicle design, mission architecture, space stations , lunar exploration, spacecraft propulsion , robotic and crewed exploration of the Solar System, interstellar travel , interstellar communications , extraterrestrial intelligence , philosophy , and cosmology . It is published monthly by the British Interplanetary Society .
The journal was established in 1934 when the British Interplanetary Society was founded. The inaugural editorial stated:
The ultimate aim of the society, of course, is the conquest of space and thence interplanetary travel.....(the) immediate task is the stimulation of public interest in the subject of interplanetary travel and the dissemination of knowledge concerning the true nature of the difficulties which as present hinder its achievements . [ 1 ]
The first issue was only a six-page pamphlet , but has the distinction of being the world's oldest surviving astronautical publication. [ citation needed ]
Notable papers [ according to whom? ] published in the journal include:
Some of the people that have been editor-in-chief of the journal are: | https://en.wikipedia.org/wiki/Journal_of_the_British_Interplanetary_Society |
The Journal of the Chemical Society, Faraday Transactions was a peer-reviewed scientific journal published from 1905 until 1998. The journal was originally published by the Faraday Society under the name Transactions of the Faraday Society and was renamed in 1972.
The journal began its publication in 1905 as Transactions of the Faraday Society . When the society merged with the other chemistry societies of the United Kingdom to form the Royal Society of Chemistry , the publication of the journal was transferred to the Chemical Society in 1972 as part of the merger negotiations. The journal was renamed Journal of the Chemical Society, Faraday Transactions , and split in two ( Faraday Transactions I: Physical Chemistry in Condensed Phases and Faraday Transactions II: Molecular and Chemical Physics ). After the merger, the Royal Society carried the publication until its end. In 1990, the two journals merged into a single Journal of the Chemical Society, Faraday Transactions , which continued publication until 1998 when it merged with a number of other physical chemistry journals published by different societies to form Physical Chemistry Chemical Physics .
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The Journal of the European Ceramic Society is a monthly peer-reviewed scientific journal published by Elsevier on behalf of the European Ceramic Society . It covers research related to conventional categories of ceramic : structural, functional, traditional or composite. It was established in 1985 as the International Journal of High Technology Ceramics , obtaining its current name in 1989.
This journal is abstracted and indexed in:
According to the Journal Citation Reports , the journal has a 2022 impact factor of 5.7. [ 4 ] | https://en.wikipedia.org/wiki/Journal_of_the_European_Ceramic_Society |
The Journal of the IEST is a peer-reviewed scientific journal and the official publication of the Institute of Environmental Sciences and Technology (IEST). It covers research on simulation , testing , modeling, control , and the teaching of the environmental sciences and technologies. The journal was established in 1958 as the Journal of Environmental Engineering . In October 1959, it was renamed Journal of Environmental Sciences and obtained its current title in 1998.
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The Journal of the Mechanics and Physics of Solids is a monthly peer-reviewed scientific journal covering research, theory, and practice concerning the properties of materials. The journal was established in 1952 by Rodney Hill and is published by Elsevier . As of February 2025, the editor-in-chief is Vikram Deshpande ( University of Cambridge ). According to the Journal Citation Reports , the journal has a 2023 impact factor of 5.0. [ 1 ]
The journal is abstracted and indexed in: | https://en.wikipedia.org/wiki/Journal_of_the_Mechanics_and_Physics_of_Solids |
The Journal of the Royal Institute of Chemistry was a scientific journal published by the Royal Institute of Chemistry which combined with other societies in 1980 to form the Royal Society of Chemistry (RSC). It had various names, including those with the title of the Institute prior to gaining its royal charter:-
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The jovilabe is a brass scientific instrument , undated and of unknown maker, currently in the collection of the Museo Galileo in Florence , Italy. [ 1 ]
The jovilabe was used by Galileo Galilei to determine the orbital periods of Jupiter's moons and to compute the times of their eclipses .
The instrument is engraved with tables showing the mean motions of each of the four moons. Two connected disks of different diameters are rotated by means of a movable rod. They are used to create a "view from the Sun " of the movements of Jupiter's moons observed from the Earth (movements that seem irregular because of the heliocentric motions of the Earth and Jupiter).
After announcing the discovery of Jupiter's moons in his 1610 treatise Sidereus Nuncius , Galileo began the systematic study of their periods in 1611, developing a micrometer for the purpose.
Galileo immediately realized that eclipses of the moons could provide a precise method to determine longitude .
Galileo compiled tables of the periods that he offered, with his telescopes , first to the King of Spain (1611, 1612, 1616, and 1627-1628), then to the States General of Holland (1637-1641). To convince his Spanish interlocutors that Jupiter and its moons could be observed on unstable ground, such as a ship's deck, Galileo designed a special helmet carrying a small telescope on a hinged mount. The device was named the celatone (celata = "helmet" in Italian). In this second proposal, he also described the advantages of applying the pendulum to the clock . Despite the interest they aroused, neither of his proposals were accepted. [ 1 ] [ 2 ]
Mara Miniati, ed. (1991). Museo di storia della scienza: catalogo . Firenze: Giunti. p. 60, board n. 3. ISBN 88-09-20036-5 .
Righini Bonelli, Maria Luisa (1971). "Galileo, l'orologio, il giovilabio". Physis Riv. Internaz. Storia Sci . 13 (4): 412– 420.
Bedini, Silvio A (1986). "The Galilean jovilabe". Nuncius . 1 (1): 24– 26.
"Museo Galileo - object description" . | https://en.wikipedia.org/wiki/Jovilabe |
Joyce Mary Waters, Lady Waters ONZM (née Partridge ; born 2 June 1931) is a New Zealand inorganic chemist and X-ray crystallographer , who is currently professor emeritus at Massey University . She was the second woman to receive a PhD in chemistry at the University of Auckland, and the first woman to serve as president of the New Zealand Institute of Chemistry.
Waters was born Joyce Mary Partridge in Auckland on 2 June 1931, the daughter of Mary Elizabeth Partridge (née Harrison) and Thomas Harold Charles Partridge. [ 1 ] She was educated at Diocesan School for Girls, Auckland , from 1938 to 1949, and went on to study at Auckland University College , graduating Bachelor of Science in 1954, Master of Science with first-class honours in 1955, and PhD in 1960. [ 1 ] [ 2 ] The title of her doctoral thesis, supervised by John Llewellyn and David Hall , was A study of some co-ordination compounds formed between nickel diammines and the nitrite ion . [ 3 ] She was the second woman to complete a PhD in chemistry at Auckland. [ 4 ]
In 1959, she married fellow inorganic chemist Neil Waters , who was knighted in 1995. [ 1 ]
Waters was appointed as a lecturer in chemistry at the University of Auckland in 1961, rising to the rank of associate professor. [ 1 ] In 1983, she joined Massey University as a senior research fellow and associate professor in chemistry, and in 2000 she was made a full professor at Massey's Albany campus. [ 1 ] Following her retirement, she was conferred with the title of professor emeritus. [ 4 ]
Her research focused on the determination of molecular structure using X-ray crystallography. [ 1 ] An early publication by Waters was the first to describe the structure of a coordination complex containing a metal–hydrogen bond. [ 4 ]
Waters served as president of the New Zealand Institute of Chemistry in 1989–1990, and was the first woman to hold the position. [ 1 ] [ 4 ]
Following her formal retirement, Waters continued part-time research and teaching activities at Massey Albany. [ 4 ] Her husband, Neil Waters, died in Auckland in 2018. [ 5 ]
In 1996, Waters was awarded the Massey Medal of Massey University, in recognition of services to the university and to science. [ 1 ] [ 6 ] In the 2006 New Year Honours , she was appointed an Officer of the New Zealand Order of Merit , for services to chemistry. [ 7 ]
Waters was elected a Fellow of the Royal Society of New Zealand in 1999, [ 8 ] and is also a Fellow of the New Zealand Institute of Chemistry. [ 1 ] | https://en.wikipedia.org/wiki/Joyce_Waters |
Jozef Stefaan "Jeff", Baron Schell (20 July 1935 – 17 April 2003) was a Belgian molecular biologist . [ 1 ] [ 2 ]
Schell studied zoology and microbiology at the University of Ghent , Belgium. From 1967 to 1995, he worked as a professor at the university. From 1978 to 2000 he was director and head of the Max Planck Institute for Plant Breeding Research (Institut für Züchtungsforschung) at the Max-Planck-Gesellschaft in Cologne , Germany. He received many prizes, among which were the Francqui Prize in 1979, the Wolf Prize in Agriculture in 1990, and the Japan Prize in 1998, which he shared with Marc Van Montagu . [ 3 ] He also was appointed Professeur Honoraire, Collège de France , Paris in 1998. He was granted the title of Baron by Baudouin of Belgium.
Schell was a pioneer in genetics who focused on the interaction between plants and soil bacteria. Along with his colleague, Marc Van Montagu , Jeff Schell discovered the gene transfer mechanism between Agrobacterium and plants, which resulted in the development of methods to alter Agrobacterium into an efficient delivery system for gene engineering in plants. Besides being a prominent scientist, in 1982 he co-founded, with Marc Van Montagu, the successful biotech company Plant Genetic Systems Inc., now part of Bayer CropScience .
This article about a Belgian scientist is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Jozef_Schell |
Jscrambler is a technology company mainly known for its JavaScript obfuscator and eponymous monitoring framework. The obfuscator makes it harder to reverse engineer a web application's client-side code and tamper with its integrity. For real-time detection of web skimming , DOM tampering and user interface changes, the monitoring framework can be used. [ 1 ] Jscrambler's products are used in a number of sectors including finance, broadcasting and online gaming. [ 2 ] [ 3 ] [ 4 ]
Jscrambler started as AuditMark, which was founded in 2009 by Pedro Fortuna and Rui Ribeiro. The company's initial focus was developing a solution to fight click-fraud in advertising campaigns, since the traffic audit mechanism was JavaScript dependent. The name of the flagship product - Jscrambler - also became the name of the company, which was officially founded in 2014. [ citation needed ] In September 2021, Jscrambler raised US$15 million in a series A led by Ace Capital Partners, with participation from Sonae IM and Portugal Ventures. [ 5 ] | https://en.wikipedia.org/wiki/Jscrambler |
In mathematics , the Jucys–Murphy elements in the group algebra C [ S n ] {\displaystyle \mathbb {C} [S_{n}]} of the symmetric group , named after Algimantas Adolfas Jucys and G. E. Murphy, are defined as a sum of transpositions by the formula:
They play an important role in the representation theory of the symmetric group .
They generate a commutative subalgebra of C [ S n ] {\displaystyle \mathbb {C} [S_{n}]} . Moreover, X n commutes with all elements of C [ S n − 1 ] {\displaystyle \mathbb {C} [S_{n-1}]} .
The vectors constituting the basis of Young's "seminormal representation" are eigenvectors for the action of X n . For any standard Young tableau U we have:
where c k ( U ) is the content b − a of the cell ( a , b ) occupied by k in the standard Young tableau U .
Theorem ( Jucys ): The center Z ( C [ S n ] ) {\displaystyle Z(\mathbb {C} [S_{n}])} of the group algebra C [ S n ] {\displaystyle \mathbb {C} [S_{n}]} of the symmetric group is generated by the symmetric polynomials in the elements X k .
Theorem ( Jucys ): Let t be a formal variable commuting with everything, then the following identity for polynomials in variable t with values in the group algebra C [ S n ] {\displaystyle \mathbb {C} [S_{n}]} holds true:
Theorem ( Okounkov – Vershik ): The subalgebra of C [ S n ] {\displaystyle \mathbb {C} [S_{n}]} generated by the centers
is exactly the subalgebra generated by the Jucys–Murphy elements X k . | https://en.wikipedia.org/wiki/Jucys–Murphy_element |
Judd–Ofelt theory is a theory in physical chemistry describing the intensity of electron transitions within the 4 f shell of rare-earth ions in solids and solutions. [ 1 ] [ 2 ] [ 3 ] It provides a mathematical framework for predicting and analyzing the spectra of rare-earth ions in solids and solutions, in particular branching ratios, radiative lifetimes, and oscillator strengths.
Judd-Ofelt theory may be used to predict and analyze the intensities of intra 4 f electronic dipole transitions. Such transitions are disallowed by Electronic Dipole Transition Selection rules in free space, as the initial and final states have the same parity. However, intra 4 f transitions have been observed. The transition strengths and the transition changing the orbital angular momentum quantum number are not consistent with them being Magnetic Dipole Transitions.
This apparent discrepancy is reconciled by treating the crystal field an ion in a solid experiences as a perturbation to the free space Hamiltonian. This perturbation mixes free space electronic states of opposite parity (namely the rare earth ion's ground 4 f n electronic configuration with the opposite parity 4 f n-1 5 d ). Thus Electronic Dipole transitions between these crystal field perturbed electronic states do not violate this parity change selection rule.
The theory quantitatively describes this mixing using three phenomenological parameters particular to the host crystal, denoted as Ω λ {\displaystyle \Omega _{\lambda }} (where λ = 2 , 4 , 6 {\displaystyle \lambda =2,4,6} ). These parameters account for the asymmetric nature of the crystal field and enable the calculation of transition probabilities, oscillator strengths, and radiative lifetimes of excited states, which are crucial for the development of various photonic devices such as lasers and optical amplifiers. [ 4 ]
Like Russell-Saunders Coupling (LS-Coupling), Judd-Ofelt theory can be simplified to a list of selection rules. The rules for Judd-Ofelt Induced Electric dipole transitions are listed in the following table and compared to LS-coupling Magnetic and Electric dipole transitions. [ 5 ]
Term symbols in LS-Coupling describe the total orbital angular momentum ( L {\displaystyle L} ), total spin ( S {\displaystyle S} ), and total angular momentum ( J = S + L {\displaystyle J=S+L} ). π {\displaystyle \pi } is the parity of an electronic configuration.
For example let us apply these selection rules to triply ionized Europium (Eu 3+ ). Eu 3+ has an electronic configuration of [ Xe ]4 f 6 . The ground term symbol for this configuration (according to Hund's Rules ) is 7 F 0 .
Applying the above selection rules, transitions from this state to 5 D 2 , 5 D 4 , and 5 D 6 are allowed, but not to 5 D 1 , 5 D 0 , or 5 L 7 (violating the restrictions on J {\displaystyle J} ). [ 5 ]
The theory was introduced independently in 1962 by Brian R. Judd of the University of California, Berkeley , and PhD candidate George S. Ofelt at Johns Hopkins University . [ 2 ] Their work was published in Physical Review and the Journal of Chemical Physics , respectively. [ 6 ] [ 7 ] Judd and Ofelt did not meet until 2003 at a workshop in Lądek-Zdrój , Poland . [ 1 ]
Judd-Ofelt Theory has become a standard tool in the field of lanthanide spectroscopy , providing insights into the optical properties of rare earth-doped materials and aiding in the design of materials for color display systems, fluorescent lamps, and lasers. [ 8 ] Their work was cited approximately 2000 times between 1962 and 2004. [ 1 ] Brian M. Walsh of NASA Langley places Judd and Ofelt's theory at the "forefront" of a 1960s revolution in spectroscopic research on rare-earth ions. [ 2 ]
Judd–Ofelt intensity parameters can be calculated from absorption spectrum of any lanthanide by the RELIC analysis software. [ 3 ] The intensity parameters and derived quantities (oscillator strengths, radiative transition probabilities, luminescence branching ratios, excited state radiative lifetimes, and estimates of quantum efficiencies) of Eu 3+ doped compounds, can be obtained by the JOES application software from their emission spectrum. [ 11 ] [ 12 ] Theoretical Judd-Ofelt intensity parameters for Eu 3+ can be obtained using the LUMPAC software. [ 13 ] Additionally, the JOYSpectra web platform provides these parameters for all Ln 3+ ions. [ 14 ] [ 15 ] | https://en.wikipedia.org/wiki/Judd–Ofelt_theory |
In mathematical logic , a judgment (or judgement ) or assertion is a statement or enunciation in a metalanguage . For example, typical judgments in first-order logic would be that a string is a well-formed formula , or that a proposition is true . Similarly, a judgment may assert the occurrence of a free variable in an expression of the object language, or the provability of a proposition . In general, a judgment may be any inductively definable assertion in the metatheory .
Judgments are used in formalizing deduction systems : a logical axiom expresses a judgment, premises of a rule of inference are formed as a sequence of judgments, and their conclusion is a judgment as well (thus, hypotheses and conclusions of proofs are judgments). A characteristic feature of the variants of Hilbert-style deduction systems is that the context is not changed in any of their rules of inference, while both natural deduction and sequent calculus contain some context-changing rules. Thus, if we are interested only in the derivability of tautologies , not hypothetical judgments, then we can formalize the Hilbert-style deduction system in such a way that its rules of inference contain only judgments of a rather simple form. The same cannot be done with the other two deductions systems: as context is changed in some of their rules of inferences, they cannot be formalized so that hypothetical judgments could be avoided—not even if we want to use them just for proving derivability of tautologies.
This basic diversity among the various calculi allows such difference, that the same basic thought (e.g. deduction theorem ) must be proven as a metatheorem in Hilbert-style deduction system, while it can be declared explicitly as a rule of inference in natural deduction .
In type theory , some analogous notions are used as in mathematical logic (giving rise to connections between the two fields, e.g. Curry–Howard correspondence ). The abstraction in the notion of judgment in mathematical logic can be exploited also in foundation of type theory as well. | https://en.wikipedia.org/wiki/Judgment_(mathematical_logic) |
In China, judgment defaulter ( Chinese : 失信被执行人 ) [ 1 ] or court defaulters , commonly known as laolai ( Chinese : 老赖 ) or untrustworthy person ( Chinese : 失信人 ), is defined as a person who is able to fulfill legal obligations determined by the court, but has refused to do so, or illegally tries to evade enforcement such as hiding their assets. [ 2 ]
According to the relevant regulations, persons who receive default judgment by the People's Courts are subject to restrictions on "high spending" or "high consumption" that are unrelated to basic living or business activities. These can include bans from traveling on high speed trains, or not being able to have your children go to private schools . [ 3 ] [ 4 ] [ 5 ] Jeremy Daum, a senior research fellow at Yale Law School's Paul Tsai China Center, explains that the idea is that since the majority of "court awards" are going to be monetary, the "judgement defaulters" should not be continuing to be spending a lot of money if they have not yet paid back the court award, and instead their money should be spent to "fix that problem". [ 6 ]
According to statistics from the Supreme People's Court , the number of the cases concluded by People's Courts at all levels from 2008 to 2012 in which the defendant had property, more than 70 percent of the defendants had evaded, avoided or even violently resisted enforcement, and less than 30 percent of them had automatically fulfilled their obligations. It is also reported that the chronic problems caused by the laolai have seriously affected the harmony and stability of society. [ 7 ] To this end, at the end of August 2013, the Supreme People's Court issued Several Provisions on the Publication of Information on the List of Judgement Defaulters . [ 7 ] [ 8 ]
According to the Decision of the Supreme People's Court on Amending the Several Provisions of the Supreme People's Court on the Publication of Information on the List of Judgment Defaulters in Default of Trust adopted at the 1582nd meeting of the Judgment Committee of the Supreme People's Court on July 1, 2013, and amended according to the 1707th meeting of the Judgment Committee of the Supreme People's Court on January 16, 2017, the Supreme People's Court on the Publication of Information on the List of judgment defaulters in Default provides that the people's courts at all levels shall list judgment defaulters and impose credit discipline on them in accordance with the law: [ 9 ]
According to the Regulations , the period of inclusion in the list of persons who have failed to trust is two years. When the judgment defaulter has engaged in violence, threats to obstruct, resisted the implementation, or if the circumstances are particularly serious or the judgment defaulter has a number of breaches of trust, the period can be extended by 1 to 3 years. In addition, the people's courts at all levels shall not include the judgment defaulter in the list under one of the following circumstances, in accordance with the provisions of Article 1, paragraph 1: [ 9 ]
In addition, if the judgment defaulter is a minor, the people's courts at all levels shall not include him/her in the list of judgment defaulters. [ 9 ]
According to the Several Provisions of the Supreme People's Court on the Publication of Information on the List of Judgement Defaulters , the recorded and published information on the list of judgment defaulters shall include the following: [ 9 ]
On October 24, 2013, the information publication and query platform of the list of judgment defaulters of the national courts (now China Defaulter Information Public Notification ) was opened to the public. The public can input the name or name of the judgment defaulter to inquire about the information of the judgment defaulter, and the above information is announced to the public. [ 10 ] In addition, local courts can also publish information on the list of judgment defaulters through bulletin boards, newspapers, radio, television, the Internet, and press conferences. [ 7 ] In recent years there have also been court publicity of judgment defaulters through cinema screenings of films, [ 11 ] and the information on the list of judgment defaulters is published in the form of Douyin and other social media. [ 12 ] In July 2014, the Executive Bureau of the Supreme People's Court and People's Daily Online jointly launched the Ranking of Judgment Defaulter . [ 13 ]
According to the Several Provisions of the Supreme People's Court on the Publication of Information on the List of Judgment Defaulter in Default of Trust, the Judgment Defaulter in default of trust will be subject to credit discipline in government procurement, bidding and tendering, administrative approval, government support, financing and credit, market access, qualification recognition, etc. [ 9 ] According to the Decision of the Supreme People's Court on Amending the Several Provisions of the Supreme People's Court on Restricting High Consumption of Judgment Defaulter adopted at the 1487th Session of the Judicial Committee of the Supreme People's Court on May 17, 2010, and Amended in accordance with the Decision of the Supreme People's Court on Amending Certain Provisions of the Supreme People's Court on Restricting the High Consumption of the Judgment Defaulter adopted at the 1657th Meeting of the Judicial Committee of the Supreme People's Court on July 6, 2015 Supreme People's Court on Restricting the High Consumption of the Judgment Defaulter and Related Consumption Several Provisions on Consumption " stipulates that persons (natural persons) included in the list of judgment defaulters shall not engage in the following acts of high consumption and consumption not essential to life and work: [ 14 ]
In addition to the above measures, the judgment defaulter included in the list see their housing, bank accounts, pension , mobile payment accounts (such as Alipay , WeChat Pay , etc.) frozen and seized, and the judgment defaulter is not allowed to serve as the legal representative, director, supervisor, and senior management of any company nationwide, nor be allowed to enroll his or her children in private schools , and their speculation in stocks, leaving the country, taking out loans or applying for credit cards in financial institutions will also be restricted. At the same time, vehicles under the defaulter's name are not allowed to drive into the Expressways of the People's Republic of China , and once a vehicle under the defaulter's name enters or leaves an expressway toll booth, the vehicle will be suspended and transferred to the court by the highway enforcement brigade. According to the Criminal Law of the People's Republic of China Amendment (IX), which was implemented on November 1, 2015, people's court judgments and rulings have the ability to perform but refuse to do so, will be punished with "refusal to take action called by the judgment. For serious circumstances, the penalty shall be imprisonment for up to three years, detention, or a fine; if the circumstances are particularly serious, the penalty shall be imprisonment for a term of more than three years and up to seven years and a fine. [ 16 ] [ 17 ]
Since July 2015, Zhima Credit , a subsidiary of Ant Group , and the Supreme People's Court have realized a system connection to update the data of judgment defaulters in real time. Once an Alipay user is included in the list of judgment defaulters, their Sesame Credit score will be deducted, and their consumption and shopping at Sesame Credit's merchant partners will also be restricted. [ 18 ] In addition, there are also some places that cooperate with communication operators to set up exclusive colored ring for the judgment defaulter, and the opening cannot be canceled without the consent of the court. If the public calls the phone number under the name of the judgment defaulter, an alert will be reported that the owner is listed as a judgment defaulter. [ 19 ] In Beijing, people who are included in the list of judgment defaulters are not allowed to participate in the minibus lottery. [ 20 ]
According to a press conference held by the Supreme People's Court on July 10, 2018, as of July 2018, there were 7.89 million cases of judgment defaulters in mainland China under publication, involving 4.4 million judgment defaulters. In terms of punishment, 12.22 million people have been restricted from purchasing air tickets, 4.58 million people have been restricted from purchasing tickets for moving trains and high-speed trains, and 280,000 people have been restricted from serving as legal representatives and executives of enterprises. Nationwide, 2.8 million judgment defaulters are forced to fulfill their obligations automatically due to the pressure of credit discipline. [ 21 ]
Prominent persons included in the list of judgment defaulter judgment defaulters | https://en.wikipedia.org/wiki/Judgment_defaulter |
Judicial interpretation is the way in which the judiciary construes the law , particularly constitutional documents, legislation and frequently used vocabulary . This is an important issue in some common law jurisdictions such as the United States , Australia and Canada , because the supreme courts of those nations can overturn laws made by their legislatures via a process called judicial review .
For example, the United States Supreme Court has decided such topics as the legality of slavery as in the Dred Scott decision , and desegregation as in the Brown v Board of Education decision, and abortion rights as in the Roe v Wade decision. As a result, how justices interpret the constitution, and the ways in which they approach this task has a political aspect. Terms describing types of judicial interpretation can be ambiguous; for example, the term judicial conservatism can vary in meaning depending on what is trying to be "conserved". One can look at judicial interpretation along a continuum from judicial restraint to judicial activism , with different viewpoints along the continuum.
Phrases which are regularly used, for example in standard contract documents, may attract judicial interpretation applicable within a particular jurisdiction whenever the same words are used in the same context.
In the United States , there are different methods to perform judicial interpretation:
Examples of phrases which have been the subject of judicial interpretation include: | https://en.wikipedia.org/wiki/Judicial_interpretation |
Judicial populism or juridical populism is a phenomenon where the judgments and actions of the courts are driven by the perception of the masses or certain groups. [ 1 ] The term, which some refer to as popular constitutionalism , has been described as a reaction to the perceived elitist bias in the legal system.
Judicial populism can also refer to the actions of the courts that reflect public sentiment or those aimed at garnering public support for the judicial institution. [ 2 ]
Judicial populism is considered an aspect of populism , particularly the strand that claims to represent the interests of the people against a corrupt elite. [ 3 ] Due to accusations of excessive privileges, inefficiencies, and possible political corruption , there is an increased hostility towards the judicial system and the creation of an atmosphere of distrust for the courts. [ 2 ] Activism among populist groups calls for judicial decisions that reflect the collective will of the people within a particular subculture.
In response, there are court judgments that are made as a form of self-representation to appease the public, obtain support or legitimacy by reflecting public sentiment. This can be demonstrated in the so-called dialectic court proceedings, which no longer focus on the evaluation of evidence but their legitimacy. [ 4 ] The position is that this type of populism can reduce the alienation or distance of the citizens to the judicial institution due to an expectation that decisions are more meaningful to their lives. [ 4 ]
There are also theorists who maintain that judicial decisions are anti-democratic in character and view these decisions as judicial intervention. [ 5 ] This position is prominent in the antagonism towards decisions involving social rights where the constitutional backgrounds of judges are considered inadequate due to issues of technical competence or a perceived judicial prejudice. [ 5 ] It is also argued that judges are not elected to their positions and, for this reason, must not be allowed to decide on the social or economic path of a country. [ 5 ]
In the United States, the call for judicial populism also emerges according to political ideologies. In the past, it came with the conservative assault to the so-called "judicial supremacy" as the courts outlawed segregation and created reproductive rights , among other issues. [ 6 ] In the modern period, the call is often made by liberal critics who assail what is perceived as "right-wing rulings". [ 6 ]
As a theory, judicial populism holds that the law emanates from some kind of collective general will. [ 7 ] It is founded on democratic and participatory theory wherein the people or at least their elected representatives get to decide policy, the state's developmental path, and the administration of justice. [ 5 ] Larry Kramer , for instance, argued that the people do not only share in construing the Constitution but also render the final judgment concerning its meaning. [ 6 ] The concept is also a basis of the Chinese legal tradition established during the Cultural Revolution -era and its modern revival. [ 8 ] It draws from the cultural belief of the non-finality of justice as well as the revolutionary values such as democratic justice and deliberative justice , which rely on the collective judgment of the people. [ 9 ]
Critics argue that instead of the courts serving as places that determine the liability for criminally relevant acts, the emergence of judicial populism crushes the criminal justice system as it transforms trials into methods of social control. [ 10 ] The opposing concept to judicial populism is judicial professionalism. This view maintains that knowledge, rationality, and ethics should be the focus in legal practice. [ 1 ] There is also a requirement for judges to be neutral and to avoid conflict of interest, a component that is present in judicial populism as the judge is involved in local affairs and forges a close relationship with the people. [ 9 ]
Judicial populism is distinguished from judicial activism , which is described as a phenomenon wherein judges allow their personal views to guide their decisions. [ 11 ] Like judicial populism, the latter - as described by Bradley Canon - draws from the constitutional dialogue/constitutional interdependence paradigm, which describes the judiciary as a participant to the constitutional interactions that involve other government branches. Here, instead of an omnipotent institution, the judiciary operates according to a framework based on interdependency and interaction while assuming the role of active protector of core social values. [ 12 ] However, judicial activism is about the forced reading of the law by judges with the goal different from the intention of the legislative branch. [ 13 ]
An example of judicial populism is Mark Tushnet 's suggestion of a populist American constitutional law that advances the so-called "thin Constitution", which would codify constitutionally protected and enforceable positive economic and social rights. [ 14 ]
There is also the case of judicial elections, which has been identified as an instrument of popular constitutionalism. [ 15 ] This framework emphasizes the importance of state judicial elections in the United States, particularly how the elected state justices can "stimulate and structure constitutional deliberations" on the national level. [ 16 ]
Mass media has been cited for its role in dictating judicial agenda. [ 4 ] It serves as a platform where the judicial institution is evaluated, facilitating new types of accountability regarding how justice is administered. [ 17 ] For instance, it is claimed that media reporting has led to juristic activism that favor a populist expansion of fundamental rights and natural justice . [ 17 ]
Cases of judicial populism include its emergence in Brazil since the mass protests of 2013. The series of political and economic crises that ensued have influenced the shift towards judicial decisions that involve judicial self-presentation before the public. [ 18 ] It is also observed that judges at various points have made decisions sought by the masses or the middle class, promulgating decisions that have no legal arguments, no constitutional basis, and narrow constitutional protection in the name of justice. [ 19 ] | https://en.wikipedia.org/wiki/Judicial_populism |
Judith Klein-Seetharaman (born May 30, 1971) is a German-American biochemist who is a professor at Arizona State University . Her research considers the structure-function properties of proteins using computational bio-linguistics. She was supported by the Bill & Melinda Gates Foundation to identify novel therapies to tackle HIV .
Klein-Seetharaman was born in Germany. She completed her undergraduate training at the University of Cologne , where she earned dual honours in biology and chemistry. [ 2 ] [ 3 ] After earning her doctorate, she moved to the United States , where she worked in the laboratory of Har Gobind Khorana at the Massachusetts Institute of Technology . [ 1 ] [ 2 ] Her research considered conformational changes in rhodopsin , the G protein coupled receptor. [ 4 ] She was a postdoctoral researcher at MIT with Harald Schwalbe , focusing on nuclear magnetic resonance spectroscopy . After eight months as a postdoc, Klein-Seetharaman moved Carnegie Mellon University where she worked with Raj Reddy in biology. She was eventually appointed to the faculty at Carnegie Mellon. [ 1 ] [ 5 ]
Klein-Seetharaman moved to the University of Pittsburgh as an assistant professor in 2002 and was promoted to associate professor in 2009. [ 1 ] She joined the Warwick Medical School as a professor in medicine in 2013. [ 1 ] She returned to the United States in 2017, first as a professor at the Colorado School of Mines and then as a professor at the Arizona State University in 2021. [ 1 ] Her research looks to uncover the structure-property relationships of membrane proteins. [ 2 ] | https://en.wikipedia.org/wiki/Judith_Klein-Seetharaman |
Jugaad ( Hindustani : जुगाड़ jugaaḍ ( Hindi ) / جگاڑ jugaaṛ ( Urdu )) is a concept of non-conventional, frugal innovation in the Indian subcontinent . [ 1 ] It also includes innovative fixes or simple workarounds, solutions that bend the rules, or resources that can be used in such a way. It is considered creative to make existing things work and create new things with meager resources.
Jugaad is increasingly accepted [ when? ] as a management technique [ 2 ] [ 3 ] and is recognized all over the world as a form of frugal innovation . [ 4 ] Companies in Southeast Asia are adopting [ when? ] jugaad as a practice to reduce research and development costs. [ 5 ] Jugaad also applies to any kind of creative and out-of-the-box thinking or life hacks that maximize resources for a company and its stakeholders.
According to author and professor Jaideep Prabhu, jugaad is an "important way out of the current [ when? ] economic crisis in developed economies and also holds important lessons for emerging economies". [ 6 ]
Jugaad can also refer to a homemade or locally made vehicle in India, Pakistan and Bangladesh . They are made by local mechanics using wooden planks, metal sheets and parts taken from different machines and vehicles.
One type of jugaad is a quadricycle , a vehicle made of wooden planks and old SUV parts, variously known as kuddukka [ clarification needed ] and peter rehra in Northern India . However, jugaad is also used as a term for any low-cost vehicle which typically costs around Rs 50,000 (US$674.77). [ 7 ] Jugaads may be powered by a diesel engine originally intended to power agricultural irrigation pumps. They are known for poor brakes, and cannot go faster than about 60 km/h (37 mph). The vehicle often carries more than 20 people at a time in remote locations and poor road conditions.
Though no statistical data is available, it is reported that there are a number of instances of failing brakes, requiring a passenger to jump off and manually apply a wooden block as a brake. As part of research for his 2013 book, Innovation and a Global Knowledge Economy in India, Thomas Birtchnell, a lecturer of Sustainable Communities at University of Wollongong , Australia, found that of 2,139 cases of road traffic casualties in 72 hours at J N Medical College hospital in Aligarh , 13.88% of pedestrian casualties were due to jugaad . It was stated by Minister of Road Transport and Highways Pon Radhakrishnan that jugaad do not conform to the specifications of a motor vehicle under the Motor Vehicles Act, 1988 . [ 8 ] These vehicles hence do not have any vehicle registration plate and they are not registered with the Regional Transport Office (RTO). Hence, no road tax is paid on them, neither there exists any official count of such vehicles.
Jugaad vehicles are not officially recognized as road-worthy, and despite a few proposals to regulate them, vote-bank politics have trumped safety concerns. The improvised vehicles have now become rather popular as a means to transport all manner of burdens, from lumber to steel rods to school children. [ 9 ] For safety reasons the Government of India has officially banned jugaad vehicles. [ 10 ]
Another type of jugaad called bike- rehra or motorcycle- rehri , a motorcycle, moped or scooter modified into motorized trikes are used in the northern states of India , especially Punjab . [ 11 ] [ 12 ]
Another type of jugaad called phat-phatri rickshaw or phatphatiya rickshaw, WWII -era Harley Davidson motorcycles modified into motorized trikes which were earlier used in New Delhi. [ 13 ]
A variant of the jugaad vehicle in the Tamil Nadu state of Southern India is the meen body vandi . This roughly translates to 'fish bed vehicle' because they originated among local fishermen who needed a quick and cheap transport system to transport fish. It is a motorized tri-wheeler (derived from the non-motorized variant) [ 14 ] [ 15 ] with a heavy-duty suspension and a motorcycle engine—typically recycled from Czech Yezdi or Enfield Bullet vehicles. Its origins are typical of other jugaadu innovations—dead fish are typically considered unhygienic, and vehicles that carry them cannot be typically used to carry anything else. Similar vehicles can be found throughout much of Southeast Asia. [ 16 ]
Another variant of the jugaad called chakkda rickshaw, a motorcycle modified into a tri-wheeler with truck wheels in the rear, is used in the Gujarat state of India. [ 17 ]
A variant of jugaad in Pakistan is a motorcycle made into a motorized trike called chand-gari meaning "moon vehicle" or chingchee after the Chinese company Jinan Qingqi who first introduced these to the market. [ 18 ]
Today, a jugaad is one of the most cost-effective transportation solutions for rural Indians, Pakistanis, and Bangladeshis. | https://en.wikipedia.org/wiki/Jugaad |
Juice jacking is a theoretical type of compromise of devices like smartphones and tablets which use the same cable for charging and data transfer, typically a USB cable. The goal of the attack is to either install malware on the device, or to surreptitiously copy potentially sensitive data. [ 1 ] As of April 2023 [update] there have been no credible reported cases of juice jacking outside of research efforts. [ 2 ]
The Wall of Sheep, an event at Defcon , has set up and allowed public access to an informational juice jacking kiosk each year at Defcon since 2011. Their intent is to bring awareness of this attack to the general public. Each of the informational juice jacking kiosks set up at the Wall of Sheep village have included a hidden CPU, which is used in some way to notify the user that they should not plug their devices in to public charging kiosks. The first informational juice jacking kiosk included a screen that would change from "Free charging station" to a warning message that the user "should not trust public charging stations with their devices". [ 3 ] One of the researchers who designed the charging station for the Wall of Sheep has given public presentations showcasing more malicious acts that could be taken via the kiosk, such as data theft, device tracking and information on compromising existing charging kiosks. [ 4 ]
Security researcher Kyle Osborn released an attack framework called P2P-ADB in 2012, which utilized USB On-The-Go to connect an attacker's phone to a target victim's device. This framework included examples and proof of concepts that would allow attackers to unlock locked phones, steal data from a phone including authentication keys granting the attacker access to the target device owner's Google Account . [ 5 ]
Security researcher graduates and students from Georgia Tech released a proof-of-concept malicious tool "Mactans" that utilized the USB charging port on Apple mobile devices at the 2013 Blackhat USA security briefings. They utilized inexpensive hardware components to construct a small sized malicious wall charger that could infect an iPhone with the then-current version of iOS with malicious software while it was being charged. The software could defeat any security measures built into iOS and mask itself in the same way Apple masks background processes in iOS. [ 6 ]
Security researchers Karsten Nohl and Jakob Lell from SRLabs published their research on BadUSB during the 2014 Blackhat USA security briefings. [ 7 ] [ 8 ] Their presentation on this attack mentions that a cellphone or tablet device charging on an infected computer would be one of the simplest method of propagating the BadUSB vulnerability. They include example malicious firmware code that would infect Android devices with BadUSB. [ 9 ]
Researchers at Aries Security and the Wall of Sheep later revisited the juice jacking concept in 2016. They set up a "Video Jacking" charging station, able to record the mirrored screen from phones plugged into their malicious charging station. Affected devices at the time included Android devices supporting SlimPort or MHL protocols over USB, as well as the most recent iPhone using an Apple Lightning charging cable connector. [ 10 ]
Researchers at Symantec disclosed their findings on an attack they called "Trustjacking" [ 11 ] during the 2018 RSA Conference . The researchers identified that when a user approves access for a computer on an iOS device over USB, that this trusted access level is also applied to the device's iTunes API, which is accessible over Wi-Fi . This would allow attackers access to an iOS device even after the user had unplugged the device from a malicious or infected USB-based charge source.
A researcher who goes by _MG_ released a USB cable implant they called the "O.MG Cable". [ 12 ] The O.MG Cable has a microcontroller embedded within the cable and a visual inspection would likely not detect a difference between the O.MG cable and a normal charging cable. The O.MG Cable allows attackers or red team penetration testers to remotely issue commands to the cable over Wi-Fi, and have those commands run on the host computer with the O.MG cable plugged in to it.
Brian Krebs was the first to report on this attack and he coined the term "juice jacking". After seeing the informational cell phone charging kiosk set up in the Wall of Sheep at DefCon 19 in August 2011, he wrote the first article on his security journalism site, "Krebs on Security". [ 13 ] The Wall of Sheep researchers, including Brian Markus, Joseph Mlodzianowski and Robert Rowley, designed the kiosk as an information tool to bring awareness of the potential attack vector and they have discussed, but not publicly released, tools to perform malicious actions on the charging devices. [ 4 ]
An episode of the hacking series Hak5 released in September 2012 showcased a number of attacks that can be conducted using an attack framework named P2P-ADB released by Kyle Osborn. The P2P-ADB attack framework discussed utilizes one phone to attack another phone over a USB On-the-Go connection. [ 14 ]
In late 2012, a document was released by the National Security Agency (NSA) warning government employees who travel about the threat of juice jacking. The document reminded readers to only use their personal power charging cables during overseas travel, to not charge in public kiosks, and to not utilize other people's computers for charging. [ 15 ] [ 16 ]
The Android Hackers Handbook released in March 2014 has dedicated sections discussing both juice jacking and the ADB-P2P framework. [ 17 ]
Juice jacking was the central focus on an episode of CSI: Cyber . Season 1: Episode 9, "L0M1S" aired in April 2015 [ 18 ]
In November 2019, the Los Angeles Deputy District Attorney issued a public service announcement warning about the risks of juice jacking during the upcoming holiday travel season. [ 19 ] This PSA came under scrutiny due to the fact that no public cases have come to light related to malicious charging kiosks found in public or any criminal cases being tried under the Los Angeles District Attorney's purview at the time of the PSA. [ 20 ]
On April 6, 2023, the FBI Denver X.com account published a warning that "bad actors have figured out ways to use public USB ports ..." [ 21 ] as if the attack vector were novel. At nearly the same time, the FCC updated a warning published in 2019 about multiple hacking attempts without citations. "In some cases, criminals may have intentionally left cables plugged in at charging stations." [ 22 ] This update, along with tweets on April 11 gave credence to social media posts and internet news articles that spread the information as fact. There were no actual instances cited of this threat being used in the wild. The original FBI tweet was not based on specific intelligence. [ 23 ]
Already in 2013, both iOS and Android devices got updates to mitigate the threat.
Apple's iOS has taken multiple security measures to reduce the attack surface over USB including no longer allowing the device to automatically mount as a hard drive when plugged in over USB, as well as release security patches for vulnerabilities such as those exploited by Mactans. [ 6 ]
Android devices commonly prompt the user before allowing the device to be mounted as a hard drive when plugged in over USB. In release 4.2.2, Android implemented a whitelist verification step to prevent attackers from accessing the Android Debug Bridge without authorization. [ 24 ]
Juice jacking is not possible if a device is charged via a trusted AC adapter or battery backup device, or if using a USB cable with only power wires. For USB cables with data wires, a USB data blocker (sometimes called a USB condom) [ 25 ] can be connected between device and charging port to disallow a data connection. [ 26 ] | https://en.wikipedia.org/wiki/Juice_jacking |
A jukebox is a partially automated music-playing device, usually a coin-operated machine, that plays a user-selected song from a self-contained media library. Traditional jukeboxes contain records, compact discs, or digital files, and allow users to select songs through mechanical buttons, a touch screen, or keypads. They were most commonly found in diners, bars, and entertainment venues throughout the 20th century. [ 1 ]
The modern concept of the jukebox evolved from earlier automatic phonographs of the late 19th century. The first coin-operated phonograph was introduced by Louis Glass and William S. Arnold in 1889 at the Palais Royale Saloon in San Francisco. [ 2 ] The term "jukebox" itself is believed to derive from the Gullah word "juke" or "joog", meaning disorderly or rowdy, referring to juke joints where music and dancing were common. [ 3 ]
Jukeboxes became especially popular from the 1940s to the 1960s, with models produced by companies such as Wurlitzer, Seeburg, Rock-Ola, and AMI. In the digital age, traditional jukeboxes have been largely replaced by internet-enabled systems and digital streaming services, though vintage and retro-style jukeboxes remain popular in niche markets and among collectors. [ 4 ]
Coin-operated music boxes and player pianos were the first forms of automated coin-operated musical devices. These devices used paper rolls , metal disks, or metal cylinders to play a musical selection on an actual instrument, or on several actual instruments, enclosed within the device.
In the 1890s, these devices were joined by machines which used recordings instead of actual physical instruments. [ 5 ] [ 6 ]
In 1889, Louis Glass and William S. Arnold invented the nickel-in-the-slot phonograph, in San Francisco . [ 7 ] This was an Edison Class M Electric Phonograph retrofitted with a device patented under the name of ‘Coin Actuated Attachment for Phonograph’. The music was heard via one of four listening tubes. [ 8 ]
In 1928, Justus P. Seeburg , who was manufacturing player pianos, combined an electrostatic loudspeaker with a record player that was coin-operated. [ 9 ] This ‘Audiophone’ machine was wide and bulky because it had eight separate turntables mounted on a rotating Ferris wheel-like device, allowing patrons to select from eight different 10″ 78rpm records.
Also in 1928, Homer E. Capehart and some backers founded the Capehart Automatic Phonograph Company, which brought out the Orchestrope. It was a device in which the tone arm slipped between each record in a vertical stack, playing that record on which the needle fell. [ 10 ]
A similar system to Seeburg’s Audiophone was employed by the Mills Novelty Company in their 1935 Dancemaster Automatic Phonograph. The Seeburg Symphonola “Trashcan” jukebox of 1938 holds 20 10″ 78rpm records each in a shallow centreless drawer so that when the selected record’s drawer opens, the turntable can rise through the open centre of the drawer to lift the record up to meet the pickup arm at the top of the mechanism, where it plays. Working examples of both these instruments may be seen and heard at the Musical Museum , Brentford, England. [ 11 ]
Later versions of the jukebox included Seeburg’s Selectophone with 10 turntables mounted vertically on a spindle. By maneuvering the tone arm up and down, the customer could select from 10 different records. [ 8 ]
The word “jukebox” came into use in the United States beginning in 1940, apparently derived from the familiar usage “ juke joint ”, derived from the Gullah word juke , which means “bawdy”. [ 12 ] Manufacturers of jukeboxes tried to avoid using the term, associated with unreputable places, for many years. [ 13 ]
Wallboxes were an important, and profitable, part of any jukebox installation. Serving as a remote control, they enabled patrons to select tunes from their table or booth. One example is the Seeburg 3W1, introduced in 1949 as companion to the 100-selection Model M100A jukebox. Stereo sound became popular in the early 1960s, and wallboxes of the era were designed with built-in speakers to provide patrons a sample of this latest technology.
Jukeboxes were most popular from the 1940s through the mid-1960s, particularly during the 1950s. By the middle of the 1940s, three-quarters of the records produced in America went into jukeboxes. [ 14 ] Billboard published a record chart measuring jukebox play during the 1950s, which briefly became a component of the Hot 100 ; by 1959, the jukebox’s popularity had waned to the point where Billboard ceased publishing the chart and stopped collecting jukebox play data. [ 15 ] Jukeboxes were popular in 1960s and 1970s Japan. [ 16 ]
As of 2016, at least two companies still manufacture classically styled jukeboxes: Rockola, based in California, and Sound Leisure, based in Leeds in the UK. Both companies manufacture jukeboxes based on a CD playing mechanism. However, in April 2016, Sound Leisure showed a prototype of a “Vinyl Rocket” at the UK Classic Car Show. It stated that it would start production of the 140 7″ vinyl selector (70 records) in summer of the same year. [ 17 ] [ 18 ]
Since 2018, Orphéau, based in Brittany in France manufactures the original styled “Sunflower” Jukebox with the first 12″ vinyl record selector (20 records), on both sides. [ 19 ]
Traditional jukeboxes once were an important source of income for record publishers. Jukeboxes received the newest recordings first. They became an important market-testing device for new music, since they tallied the number of plays for each title. They let listeners control the music outside of their home, before audio technology became portable. They played music on demand without commercials. They also offered high fidelity listening before home high fidelity equipment became affordable. [ 8 ]
In 1995, the United States Postal Service issued a 25-cent stamp commemorating the jukebox. [ 22 ]
Disc changers are similar devices for personal use. Record changers on turntables typically lacked any selection mechanism, instead playing an entire stack of up to a dozen records in order. CD changers identical in size to standard players or inside a single-DIN car stereo hold several discs; slightly larger changers that fit on a shelf or in a car’s trunk attached to its vehicle audio system controlled from the dashboard, hold up to hundreds of discs; these can be arbitrarily autoplayed, removed, or inserted by the user. If under software control, especially for computer file storage, these are often called optical jukeboxes .
The term “jukebox” was used to describe high-capacity, hard disk mobile digital audio players due to their amount of digital space allowing someone’s entire personal music library to be stored and played anywhere. [ 23 ] [ 24 ] The term was popularized following the introduction of the Creative NOMAD Jukebox in 2000, which could store the MP3 compressed equivalent of 150 CDs of music on its six gigabyte hard drive. [ 25 ] In later years, the “classic” iPod would become the most iconic product in this category. [ 23 ]
While the number of vinyl-based jukeboxes declined, digital jukeboxes, also called the “social jukebox”, have been introduced in bars and clubs. [ 26 ] | https://en.wikipedia.org/wiki/Jukebox |
Guillaume-Jules Hoüel (7 April 1823 – 14 June 1886) was a French mathematician . He entered the École Normale Supérieure in 1843 and received his doctoral degree in 1855 from the Sorbonne . He was sought by Urbain Le Verrier at the Paris Observatory , but chose instead to return to Thaon to study there. In 1859 he began to teach at Bordeaux .
In 1863 Hoüel expressed his doubts about the verifiability of the parallel postulate of Euclid . [ 1 ]
In 1867 Hoüel produced French translations of two key publications of non-Euclidean geometry : Lobachevski 's Geometrical Studies on the Theory of Parallels [ 2 ] and Bolyai 's Science of Absolute Space . [ 3 ]
Hoüel published a four volume work titled Théorie Élémentaire des Quantités Complexes . Volume four, published in 1874, began with a discussion of properties of algebraic operations (commutativity, associativity, distribution, and inverses) and used the algebra of quaternions and versors to describe spherical trigonometry . [ 4 ] However, in 1890 P. G. Tait revealed his dissatisfaction with Hoüel's changes in notation with text that Tait had given for Hoüel's use. Tait wrote: [ 5 ]
In 1876 Hoüel reviewed a Russian language quaternion textbook written by Romer (1868) [ 6 ] | https://en.wikipedia.org/wiki/Jules_Hoüel |
Jules Lefèvre (1863 – May 1944) [ 1 ] was a French biochemist and writer. He was for his work in bioenergetics , thermoregulation , and nutrition. His research in bioenergetics, particularly his 1911 publication Chaleur animale et bioénergétique ("Animal Heat and Bioenergetics"), contributed to early understandings of metabolic heat production, body heat exchange, and the physiological mechanisms involved in thermoregulation. He also authored the Traité de Bioénergétique ("Treatise on Bioenergetics") in 1911, one of the first comprehensive works on the emerging field of bioenergetics.
Lefèvre's work extended beyond bioenergetics to include topics related to vegetarianism . In 1904, he published Examen scientifique du végétarisme ("A Scientific Investigation into Vegetarianism"), which explored vegetarianism from a scientific, nutritional, and physiological perspective and introduced the term végétalisme to describe a vegan diet.
Throughout his career, Lefèvre received several awards for his contributions to science, including the Laborde Prix (1894), the Montyon Prix for experimental physiology (1905), Petit-d'Ormoy and Mallanet Prix (1913), and the Grand Prix Albert de Monaco (1939). In 1923, he was awarded one of the three rosettes of the Legion of Honour in recognition of his scientific work.
Lefèvre studied at the École Normale Supérieure from 1884 to 1887 and at the Muséum national d'histoire naturelle from 1887 to 1888. During this period, he earned triple degrees in mathematics, physics, and chemistry, as well as natural sciences, between 1885 and 1887. [ 2 ]
Lefèvre was appointed agrégé in natural sciences in 1888, working as professor of biology at the Lycée du Havre until 1928. [ 2 ] [ 3 ] Afterward, he continued teaching biology in several private institutions, including Stanislas and Sainte-Croix. [ 2 ]
Lefèvre also designed and supervised the creation of a bioenergetics laboratory between 1923 and 1927, which became a crucial tool for studying nutrition and metabolism in both humans and animals. His laboratory was considered more advanced in flexibility and precision compared to earlier models, such as the calorimeter chamber of Atwater and Benedict . [ 2 ]
Lefèvre has been described as the "father of bioenergetics". [ 4 ] His research on animal energetics began in 1893 and led to over a hundred communications and forty original papers published in prominent scientific journals. His 1911 Treatise on Bioenergetics was the first to define the science of the "animal machine", a term he introduced. In 1929, he further developed this field in Volume VIII of his Traité de physiologie normale et pathologique ("Treatise on Normal and Pathological Physiology"). [ 2 ]
Lefèvre conducted research on human thermoregulation using calorimetric techniques. Continuing earlier work by Bordier, he studied how the thermal conductivity of the skin changes with ambient temperature, observing that the outer layers of skin reduce conductivity in cold conditions, while deeper layers continue to receive thermal energy. In 1901, he reported that heat loss at 5 °C, due to internal skin warming, could be two to three times greater than predicted by Newton's law . His 1911 publication Chaleur animale et bioénergétique ("Animal heat and bioenergetics"), included detailed information on bioenergetics, body heat exchange, and metabolic heat production during rest and physical activity. Lefèvre also described the use of ergometers and methods for direct and indirect calorimetry, and examined the effects of clothing and circadian temperature variations in night workers. [ 5 ]
Lefèvre's research focused on the mechanisms of thermoregulation, heat loss, and thermogenesis in mammals. He contributed to resolving debates regarding the role of heat in biological systems, demonstrating that heat production in organisms serves both as a byproduct of metabolic activity and as an essential function for maintaining constant core temperature, particularly in homeothermic animals. His work also established a relationship between heat loss and ambient temperature, showing that heat production accelerates as environmental temperature decreases. [ 2 ]
In 1904, Lefèvre published Examen scientifique du végétarisme by the French Vegetarian Society ; he was elected to the Society's management committee in 1905, along with Jules Grand . [ 6 ] A revised edition of the book was published in 1919. [ 7 ] An authorised English translation was published in 1923 by Fred Rothwell, as A Scientific Investigation into Vegetarianism . [ 8 ]
The book explores vegetarianism from scientific, historical, physiological, and social perspectives. It begins with a historical overview of vegetarianism, including movements in various countries and key figures like Jean-Antoine Gleizes . The second section examines the physiological basis of vegetarian doctrines, covering nutrition, food composition, and critiques of flesh-eating diets. It discusses alternative dietary systems such as fruitarianism and veganism (termed végétalisme ), and analyzes human dietary needs from a biological and anatomical standpoint. Additional chapters address the role of diet in illness, social and economic aspects of food systems, human energy and nutrition, and the body's thermal regulation in relation to diet. [ 8 ]
Lefèvre presented arguments regarding human anatomy, the health impacts of meat consumption, and its potential role in promoting behaviors such as alcohol and drug use. He suggested that the high nitrogen content in meat could disrupt intestinal health and possibly contribute to kidney failure, while providing limited energy. According to Lefèvre, plant-based glucose, particularly from fruit, was a more efficient source of energy, especially for athletes. His perspective included detailed scientific explanations of energy transformation, from sunlight through plants to humans. While his views did not heavily rely on religious or metaphysical reasoning, he implied a natural order in this process. Additionally, Lefèvre argued that vegetarianism could reduce class conflict and encourage a return to rural living. He also believed that meat consumption could foster violent behaviors, presenting vegetarianism as a countermeasure to societal decline and regression. [ 9 ]
Lefèvre received several significant awards throughout his career. These included the Laborde Prix in 1894, the Montyon Prix for experimental physiology in 1905, the Pourat Prix in 1908, and the Petit-d'Ormoy and Mallanet Prix in 1913. In 1923, Hhe was also designated to receive one of the three rosettes of the Legion of Honor in recognition of his scientific contributions. In 1939, he was awarded the Grand Prix Albert de Monaco, receiving 61 out of 63 votes. [ 4 ]
Lefèvre was the father of Abbé Luc-J. Lefèvre, who later founded the traditionalist journal La Pensée catholique . [ 10 ] | https://en.wikipedia.org/wiki/Jules_Lefèvre |
Julia Y. Chan is a professor of chemistry and biochemistry at Baylor University . Chan is an expert in the area of intermetallic crystal growth with a focus on new quantum materials. She is a fellow of both the American Chemical Society and the American Association for the Advancement of Science .
Chan moved to New York City at the age of eight and spent her childhood in North America . [ 1 ] Chan studied at Baylor University and graduated in 1993. [ 2 ] [ 3 ] Initially a music major – specialising in the violin – she soon became interested in chemistry. [ 4 ] At Baylor, Chan worked under the supervision of Carlos Manzanares and Marianna Busch. She earned her doctoral degree under the supervision of Susan M. Kauzlarich at the University of California, Davis in 1998. [ 5 ] Chan completed postdoctoral research in the ceramics division at the National Institute of Standards and Technology . [ 6 ] She has continued to play violin in her church orchestra. [ 4 ]
Chan began her career as an assistant professor of chemistry at Louisiana State University in 2000. In 2002 she was awarded an National Science Foundation CAREER Award and selected as one of the American Chemical Society women making an impact in chemistry. [ 4 ] In 2004 Chan was awarded an ExxonMobil Faculty Fellowship Award. She was part of the 2010 American Chemical Society Women Chemists of Colour Summit. [ 7 ] She joined the chemistry department at University of Texas at Dallas as a full professor in 2013. [ 2 ] In 2022 Chan moved to Baylor University .
At the Baylor University , Chan investigates the physical properties of magnetic materials synthesized in her laboratory, with a focus on the growth and characterization of quantum materials . [ 8 ] She has developed new techniques to grow single crystals of intermetallic phases. She was the Guest Editor of the American Chemical Society Inorganic Chemistry theme issue on Solid-State Inorganic Chemistry. [ 9 ] In 2019 Chan was inducted into the American Association for the Advancement of Science .
Her awards and honors include:
Her publications include: [ 17 ]
Chan is a Deputy Editor of Science Advances . [ 18 ] | https://en.wikipedia.org/wiki/Julia_Chan_(chemist) |
The Julia olefination (also known as the Julia–Lythgoe olefination) is the chemical reaction used in organic chemistry of phenyl sulfones (1) with aldehydes (or ketones ) to give alkenes (olefins)(3) after alcohol functionalization and reductive elimination using sodium amalgam [1] [2] or SmI 2 . [3] The reaction is named after the French chemist Marc Julia .
The utility of this connective olefination reaction arises from its versatility, its wide functional group tolerance, and the mild reaction conditions under which the reaction proceeds.
All four steps can be carried out in a single reaction vessel, and use of R 3 X is optional. However, purification of the sulfone intermediate 2 leads to higher yield and purity. Most often R 3 is acetyl or benzoyl , with acetic anhydride or benzoyl chloride used in the preparation of 2.
In 1973, Marc Julia and Jean-Marc Paris reported a novel olefin synthesis in which β-acyloxysulfones were reductively eliminated to the corresponding di-, tri-, or tetrasubstituted alkenes. [4] Basil Lythgoe and Philip J. Kocienski explored the scope and limitation of the reaction, and today this olefination is formally known as the Julia-Lythgoe olefination. [5] The reaction involves the addition of a sulfonyl-stabilized carbanion to a carbonyl compound, followed by elimination to form an alkene. In the initial versions of the reactions, the elimination was done under reductive conditions. More recently, a modified version that avoids this step was developed by Sylvestre Julia (no relation to Marc). [ 1 ] The former version is sometimes referred to as the Julia-Lythgoe olefination, whereas the latter is called the Julia-Kocienski olefination. In the reductive variant, the adduct is usually acylated and then treated with a reducing agent, such as sodium amalgam [6] [7] or SmI 2 . [8] Several reviews of these reactions have been published. [9] [10]
The initial steps are straightforward. The phenyl sulfone anion (2) reacts with an aldehyde to form the alkoxide (3). The alkoxide is functionalized with R 3 -X to give the stable intermediate (4). The exact mechanism of the sodium amalgam reduction is unknown but has been shown to proceed through a vinylic radical species (5) [11] . Protonation of the vinylic radical gives the desired product (6).
The stereochemistry of the alkene (6) is independent of the stereochemistry of the sulfone intermediate 4. It is thought that the radical intermediates are able to equilibrate so that the more thermodynamically stable trans-olefin is produced most often. This transformation highly favors formation of the E -alkene. [12]
The modified Julia olefination, also known as the one-pot Julia olefination is a modification of the classical Julia olefination. The replacement of the phenyl sulfones with heteroaryl sulfones greatly alters the reaction pathway. [13] The most popular example is the benzothiazole sulfone. [14] The reaction of the benzothiazole sulfone (1) with lithium diisopropylamide (LDA) gives a metallated benzothiazolyl sulfone, which reacts quickly with aldehydes (or ketones) to give an alkoxide intermediate (2). Unlike the phenyl sulfones, this alkoxide intermediate (2) is more reactive and will undergo a Smiles rearrangement [15] to give the sulfinate salt (4). The sulfinate salt (4) will spontaneously eliminate sulfur dioxide and lithium benzothiazolone (5) producing the desired alkene (6).
Since the benzothiazole variation of the Julia olefination does not involve equilibrating intermediates, the stereochemical outcome is a result of the stereochemistry of the initial carbonyl addition. As a result, this reaction often generates a mixture of alkene stereoisomers.
The Julia–Kocienski Olefination, a further refinement of the Modified Julia olefination, offers very good E -selectivity. In the Julia–Kocienski olefination [16] the alkylating agent is a tetrazole . It proceeds with the same mechanism as the benzothiazole sulfone above. The high E -selectivity of the Julia–Kocienski olefination is the result of kinetically controlled diastereoselective addition of metalated 1-phenyl-1H-tetrazol-5-yl (PT) sulfones to nonconjugated aldehydes. This yields anti-β-alkoxysulfones which stereospecifically decompose to the E -alkenes. [17] In one adaptation, [18] with t-butyltetrazoylmethyl sulfone the reaction conditions are either sodium bis(trimethylsilyl)amide at −70 °C in tetrahydrofuran or caesium carbonate at +70 °C. This reaction is named after Philip J. Kocienski for his modification to the Julia olefination.
The Julia or modified Julia olefination reaction is a powerful and versatile synthetic transformation, widely utilized in the construction of complex natural products with excellent control of geometrical isomerism.
Pterostilbene is a stilbenoid chemically related to resveratrol. It belongs to the group of phytoalexins, agents produced by plants to fight infections. [19] Pterostilbene is a naturally occurring dimethyl ether analog of resveratrol. It is believed that the compound also has anti-diabetic properties, but so far very little has been studied on this issue.
Compared to the Wittig , Wittig-Horner, Perkin , or transition-metal-catalyzed reactions to synthesize pterostilebene, the Julia olefination offers a simple, economical alternative method for preparation of pterostilbene. [20] [21]
One adaptation of the Julia-Kocienski olefination gives the synthesis of the stilbenoid resveratrol , a natural compound found in common foods like grapes, wines and nuts. Resveratrol is a biologically important stilbenoid which has been suggested to have many health benefits. The Julia-Kocienski olefination serves as a powerful reaction in the synthesis of resveratrol analogues with 3,5-bis(trifluoromethyl)phenyl sulfones. The following schematic displays the general scheme for synthesizing resveratrol analogues, where R 2 is an aryl group. [22]
In the asymmetric total synthesis of (−)-callystatin A by Amos Smith , two separate Julia olefinations were used to append two E -alkene moieties. [23] (−)-callystatin A is a member of the leptomycin family of antibiotics. The following schematic displays the Julia-Kocienski olefination used to achieve the precursor to the natural product, as indicated by use of the PT-sulfone. | https://en.wikipedia.org/wiki/Julia_olefination |
The Julian day is a continuous count of days from the beginning of the Julian period; it is used primarily by astronomers , and in software for easily calculating elapsed days between two events (e.g. food production date and sell by date). [ 1 ]
The Julian period is a chronological interval of 7980 years, derived from three multi-year cycles: the Indiction , Solar , and Lunar cycles. The last year that was simultaneously the beginning of all three cycles was 4713 BC (−4712) , [ 2 ] so that is year 1 of the current Julian period, making AD 2025 year 6738 of that Period. The next Julian Period begins in the year AD 3268. Historians used the period to identify Julian calendar years within which an event occurred when no such year was given in the historical record, or when the year given by previous historians was incorrect. [ 3 ]
The Julian day number (JDN) has the same epoch as the Julian period, but counts the number of days since the epoch rather than the number of years since then. Specifically, Julian day number 0 is assigned to the day starting at noon Universal Time on Monday, January 1, 4713 BC, proleptic Julian calendar (November 24, 4714 BC, in the proleptic Gregorian calendar ). [ 4 ] [ 5 ] [ 6 ] [ a ] For example, the Julian day number for the day starting at 12:00 UT (noon) on January 1, 2000, was 2 451 545 . [ 7 ]
The Julian date ( JD ) of any instant is the Julian day number plus the fraction of a day since the preceding noon in Universal Time. Julian dates are expressed as a Julian day number with a decimal fraction added. [ 8 ] For example, the Julian Date for 00:30:00.0 UT January 1, 2013, is 2 456 293 .520 833 . [ 9 ] This article was loaded at 2025-05-20 11:32:41 ( UTC ) – expressed as a Julian date this is 2460815.9810301.
The term Julian date may also refer, outside of astronomy, to the day-of-year number (more properly, the ordinal date ) in the Gregorian calendar , especially in computer programming, the military and the food industry, [ 10 ] or it may refer to dates in the Julian calendar . For example, if a given "Julian date" is "October 5, 1582", this means that date in the Julian calendar (which was October 15, 1582, in the Gregorian calendar – the date it was first established). Without an astronomical or historical context, a "Julian date" given as "36" most likely means the 36th day of a given Gregorian year, namely February 5. Other possible meanings of a "Julian date" of "36" include an astronomical Julian Day Number, or the year AD 36 in the Julian calendar, or a duration of 36 astronomical Julian years ). This is why the terms "ordinal date" or "day-of-year" are preferred. In contexts where a "Julian date" means simply an ordinal date, calendars of a Gregorian year with formatting for ordinal dates are often called "Julian calendars" , [ 10 ] but this could also mean that the calendars are of years in the Julian calendar system.
Historically, Julian dates were recorded relative to Greenwich Mean Time (GMT) (later, Ephemeris Time ), but since 1997 the International Astronomical Union has recommended that Julian dates be specified in Terrestrial Time . [ 11 ] Seidelmann indicates that Julian dates may be used with International Atomic Time (TAI), Terrestrial Time (TT), Barycentric Coordinate Time (TCB), or Coordinated Universal Time (UTC) and that the scale should be indicated when the difference is significant. [ 12 ] The fraction of the day is found by converting the number of hours, minutes, and seconds after noon into the equivalent decimal fraction. Time intervals calculated from differences of Julian Dates specified in non-uniform time scales, such as UTC, may need to be corrected for changes in time scales (e.g. leap seconds ). [ 8 ]
Because the starting point or reference epoch is so long ago, numbers in the Julian day can be quite large and cumbersome. A more recent starting point is sometimes used, for instance by dropping the leading digits, in order to fit into limited computer memory with an adequate amount of precision. In the following table, times are given in 24-hour notation.
In the table below, Epoch refers to the point in time used to set the origin (usually zero, but (1) where explicitly indicated) of the alternative convention being discussed in that row. The date given is a Gregorian calendar date unless otherwise specified. JD stands for Julian Date. 0h is 00:00 midnight, 12h is 12:00 noon, UT unless otherwise specified. Current value is at 11:32, Tuesday, May 20, 2025 ( UTC ) and may be cached. [ refresh ]
The Julian day number is based on the Julian Period proposed by Joseph Scaliger , a classical scholar, in 1583 (one year after the Gregorian calendar reform) as it is the product of three calendar cycles used with the Julian calendar:
Its epoch occurs when all three cycles (if they are continued backward far enough) were in their first year together. Years of the Julian Period are counted from this year, 4713 BC , as year 1 , which was chosen to be before any historical record. [ 31 ]
Scaliger corrected chronology by assigning each year a tricyclic "character", three numbers indicating that year's position in the 28-year solar cycle, the 19-year lunar cycle, and the 15-year indiction cycle. One or more of these numbers often appeared in the historical record alongside other pertinent facts without any mention of the Julian calendar year. The character of every year in the historical record was unique – it could only belong to one year in the 7980-year Julian Period. Scaliger determined that 1 BC or year 0 was Julian Period (JP) 4713 . He knew that 1 BC or year 0 had the character 9 of the solar cycle, 1 of the lunar cycle, and 3 of the indiction cycle. By inspecting a 532-year Paschal cycle with 19 solar cycles (each of 28 years, each year numbered 1–28) and 28 lunar cycles (each of 19 years, each year numbered 1–19), he determined that the first two numbers, 9 and 1, occurred at its year 457. He then calculated via remainder division that he needed to add eight 532-year Paschal cycles totaling 4256 years before the cycle containing 1 BC or year 0 in order for its year 457 to be indiction 3. The sum 4256 + 457 was thus JP 4713. [ 32 ]
A formula for determining the year of the Julian Period given its character involving three four-digit numbers was published by Jacques de Billy in 1665 in the Philosophical Transactions of the Royal Society (its first year). [ 33 ] John F. W. Herschel gave the same formula using slightly different wording in his 1849 Outlines of Astronomy . [ 34 ]
Multiply the Solar Cycle by 4845, and the Lunar , by 4200, and that of the Indiction , by 6916. Then divide the Sum of the products by 7980, which is the Julian Period : The Remainder of the Division, without regard to the Quotient , shall be the year enquired after.
Carl Friedrich Gauss introduced the modulo operation in 1801, restating de Billy's formula as:
where a is the year of the indiction cycle, b of the lunar cycle, and c of the solar cycle. [ 35 ] [ 36 ]
John Collins described the details of how these three numbers were calculated in 1666, using many trials. [ 37 ] A summary of Collin's description is in a footnote. [ 38 ] Reese, Everett and Craun reduced the dividends in the Try column from 285, 420, 532 to 5, 2, 7 and changed remainder to modulo, but apparently still required many trials. [ 39 ]
The specific cycles used by Scaliger to form his tricyclic Julian Period were, first, the indiction cycle with a first year of 313. [ d ] [ 40 ] Then he chose the dominant 19-year Alexandrian lunar cycle with a first year of 285, the Era of Martyrs and the Diocletian Era epoch, [ 41 ] or a first year of 532 according to Dionysius Exiguus . [ 42 ] Finally, Scaliger chose the post-Bedan solar cycle with a first year of 776, when its first quadrennium of concurrents , 1 2 3 4 , began in sequence. [ e ] [ 43 ] [ 44 ] [ 45 ] Although not their intended use, the equations of de Billy or Gauss can be used to determined the first year of any 15-, 19-, and 28-year tricyclic period given any first years of their cycles. For those of the Julian Period, the result is AD 3268, because both remainder and modulo usually return the lowest positive result. Thus 7980 years must be subtracted from it to yield the first year of the present Julian Period, −4712 or 4713 BC, when all three of its sub-cycles are in their first years.
Scaliger got the idea of using a tricyclic period from "the Greeks of Constantinople" as Herschel stated in his quotation below in Julian day numbers . [ 46 ] Specifically, the monk and priest Georgios wrote in 638/39 that the Byzantine year 6149 AM (640/41) had indiction 14, lunar cycle 12, and solar cycle 17, which places the first year of the Byzantine Era in 5509/08 BC, the Byzantine Creation. [ 47 ] Dionysius Exiguus called the Byzantine lunar cycle his "lunar cycle" in argumentum 6, in contrast with the Alexandrian lunar cycle which he called his "nineteen-year cycle" in argumentum 5. [ 42 ]
Although many references say that the Julian in "Julian Period" refers to Scaliger's father, Julius Scaliger , at the beginning of Book V of his Opus de Emendatione Temporum ("Work on the Emendation of Time") he states, " Iulianam vocauimus: quia ad annum Iulianum accomodata ", [ 48 ] [ 49 ] which Reese, Everett and Craun translate as "We have termed it Julian because it fits the Julian year". [ 39 ] Thus Julian refers to the Julian calendar .
Julian days were first used by Ludwig Ideler for the first days of the Nabonassar and Christian eras in his 1825 Handbuch der mathematischen und technischen Chronologie . [ 50 ] [ 51 ] John F. W. Herschel then developed them for astronomical use in his 1849 Outlines of Astronomy , after acknowledging that Ideler was his guide. [ 52 ]
The period thus arising of 7980 Julian years, is called the Julian period, and it has been found so useful, that the most competent authorities have not hesitated to declare that, through its employment, light and order were first introduced into chronology. [ 53 ] We owe its invention or revival to Joseph Scaliger, who is said to have received it from the Greeks of Constantinople. The first year of the current Julian period, or that of which the number in each of the three subordinate cycles is 1, was the year 4713 BC , and the noon of January 1 of that year, for the meridian of Alexandria, is the chronological epoch, to which all historical eras are most readily and intelligibly referred, by computing the number of integer days intervening between that epoch and the noon (for Alexandria) of the day, which is reckoned to be the first of the particular era in question. The meridian of Alexandria is chosen as that to which Ptolemy refers the commencement of the era of Nabonassar, the basis of all his calculations. [ 46 ]
At least one mathematical astronomer adopted Herschel's "days of the Julian period" immediately. Benjamin Peirce of Harvard University used over 2,800 Julian days in his Tables of the Moon , begun in 1849 but not published until 1853, to calculate the lunar ephemerides in the new American Ephemeris and Nautical Almanac from 1855 to 1888. The days are specified for "Washington mean noon", with Greenwich defined as 18 h 51 m 48 s west of Washington (282°57′W, or Washington 77°3′W of Greenwich). A table with 197 Julian days ("Date in Mean Solar Days", one per century mostly) was included for the years –4713 to 2000 with no year 0, thus "–" means BC, including decimal fractions for hours, minutes, and seconds. [ 54 ] The same table appears in Tables of Mercury by Joseph Winlock, without any other Julian days. [ 55 ]
The national ephemerides started to include a multi-year table of Julian days, under various names, for either every year or every leap year beginning with the French Connaissance des Temps in 1870 for 2,620 years, increasing in 1899 to 3,000 years. [ 56 ] The British Nautical Almanac began in 1879 with 2,000 years. [ 57 ] The Berliner Astronomisches Jahrbuch began in 1899 with 2,000 years. [ 58 ] The American Ephemeris was the last to add a multi-year table, in 1925 with 2,000 years. [ 59 ] However, it was the first to include any mention of Julian days with one for the year of issue beginning in 1855, as well as later scattered sections with many days in the year of issue. It was also the first to use the name "Julian day number" in 1918. The Nautical Almanac began in 1866 to include a Julian day for every day in the year of issue. The Connaissance des Temps began in 1871 to include a Julian day for every day in the year of issue.
The French mathematician and astronomer Pierre-Simon Laplace first expressed the time of day as a decimal fraction added to calendar dates in his book, Traité de Mécanique Céleste , in 1823. [ 60 ] Other astronomers added fractions of the day to the Julian day number to create Julian Dates, which are typically used by astronomers to date astronomical observations, thus eliminating the complications resulting from using standard calendar periods like eras, years, or months. They were first introduced into variable star work in 1860 by the English astronomer Norman Pogson , which he stated was at the suggestion of John Herschel. [ 61 ] They were popularized for variable stars by Edward Charles Pickering , of the Harvard College Observatory , in 1890. [ 62 ]
Julian days begin at noon because when Herschel recommended them, the astronomical day began at noon. The astronomical day had begun at noon ever since Ptolemy chose to begin the days for his astronomical observations at noon. He chose noon because the transit of the Sun across the observer's meridian occurs at the same apparent time every day of the year, unlike sunrise or sunset, which vary by several hours. Midnight was not even considered because it could not be accurately determined using water clocks . Nevertheless, he double-dated most nighttime observations with both Egyptian days beginning at sunrise and Babylonian days beginning at sunset. [ 63 ] Medieval Muslim astronomers used days beginning at sunset, so astronomical days beginning at noon did produce a single date for an entire night. Later medieval European astronomers used Roman days beginning at midnight so astronomical days beginning at noon also allow observations during an entire night to use a single date. When all astronomers decided to start their astronomical days at midnight to conform to the beginning of the civil day, on January 1, 1925 , it was decided to keep Julian days continuous with previous practice, beginning at noon.
During this period, usage of Julian day numbers as a neutral intermediary when converting a date in one calendar into a date in another calendar also occurred. An isolated use was by Ebenezer Burgess in his 1860 translation of the Surya Siddhanta wherein he stated that the beginning of the Kali Yuga era occurred at midnight at the meridian of Ujjain at the end of the 588,465th day and the beginning of the 588,466th day (civil reckoning) of the Julian Period, or between February 17 and 18 JP 1612 or 3102 BC. [ 64 ] [ 65 ] Robert Schram was notable beginning with his 1882 Hilfstafeln für Chronologie . [ 66 ] Here he used about 5,370 "days of the Julian Period". He greatly expanded his usage of Julian days in his 1908 Kalendariographische und Chronologische Tafeln containing over 530,000 Julian days, one for the zeroth day of every month over thousands of years in many calendars. He included over 25,000 negative Julian days, given in a positive form by adding 10,000,000 to each. He called them "day of the Julian Period", "Julian day", or simply "day" in his discussion, but no name was used in the tables. [ 67 ] Continuing this tradition, in his book "Mapping Time: The Calendar and Its History" British physics educator and programmer Edward Graham Richards uses Julian day numbers to convert dates from one calendar into another using algorithms rather than tables. [ 68 ]
The Julian day number can be calculated using the following formulas ( integer division rounding towards zero is used exclusively, that is, positive values are rounded down and negative values are rounded up): [ f ]
The months January to December are numbered 1 to 12. For the year, astronomical year numbering is used, thus 1 BC is 0, 2 BC is −1, and 4713 BC is −4712. JDN is the Julian Day Number. Use the previous day of the month if trying to find the JDN of an instant before midday UT.
The algorithm is valid for all (possibly proleptic ) Gregorian calendar dates after November 23, −4713. Divisions are integer divisions towards zero ; fractional parts are ignored. [ 69 ]
The algorithm [ 70 ] is valid for all (possibly proleptic ) Julian calendar years ≥ −4712, that is, for all JDN ≥ 0. Divisions are integer divisions, fractional parts are ignored.
For the full Julian Date of a moment after 12:00 UT one can use the following. Divisions are real numbers .
So, for example, January 1, 2000, at 18:00:00 UT corresponds to JD = 2451545.25 and January 1, 2000, at 6:00:00 UT corresponds to JD = 2451544.75.
Because a Julian day starts at noon while a civil day starts at midnight, the Julian day number needs to be adjusted to find the day of week: for a point in time in a given Julian day after midnight UT and before 12:00 UT, add 1 or use the JDN of the next afternoon.
The US day of the week W1 (for an afternoon or evening UT) can be determined from the Julian Day Number J with the expression:
If the moment in time is after midnight UT (and before 12:00 UT), then one is already in the next day of the week.
The ISO day of the week W0 can be determined from the Julian Day Number J with the expression:
This is an algorithm by Edward Graham Richards to convert a Julian Day Number, J , to a date in the Gregorian calendar (proleptic, when applicable). Richards states the algorithm is valid for Julian day numbers greater than or equal to 0. [ 72 ] [ 73 ] All variables are integer values, and the notation " a div b " indicates integer division , and "mod( a , b )" denotes the modulus operator .
For Julian calendar:
For Gregorian calendar:
For Julian or Gregorian, continue:
D , M , and Y are the numbers of the day, month, and year respectively for the afternoon at the beginning of the given Julian day.
Let Y be the year BC or AD and i, m, and s respectively its positions in the indiction, Metonic and solar cycles. Divide 6916i + 4200m + 4845s by 7980 and call the remainder r.
Example
i = 8, m = 2, s = 8. What is the year?
As stated above, the Julian date (JD) of any instant is the Julian day number for the preceding noon in Universal Time plus the fraction of the day since that instant. Ordinarily calculating the fractional portion of the JD is straightforward; the number of seconds that have elapsed in the day divided by the number of seconds in a day, 86,400. But if the UTC timescale is being used, a day containing a positive leap second contains 86,401 seconds (or in the unlikely event of a negative leap second, 86,399 seconds). One authoritative source, the Standards of Fundamental Astronomy (SOFA), deals with this issue by treating days containing a leap second as having a different length (86,401 or 86,399 seconds, as required). SOFA refers to the result of such a calculation as "quasi-JD". [ 75 ] | https://en.wikipedia.org/wiki/Julian_day |
In astronomy , a Julian year (symbol: a or a j ) is a unit of measurement of time defined as exactly 365.25 days of 86 400 SI seconds each. [ 1 ] [ 2 ] [ 3 ] [ 4 ] The length of the Julian year is the average length of the year in the Julian calendar that was used in Western societies until the adoption of the Gregorian Calendar , and from which the unit is named. Nevertheless, because astronomical Julian years are measuring duration rather than designating dates, this Julian year does not correspond to years in the Julian calendar or any other calendar. Nor does it correspond to the many other ways of defining a year.
The Julian year is not a unit of measurement in the International System of Units (SI), but it is recognized by the International Astronomical Union (IAU) as a non-SI unit for use in astronomy. [ 3 ] Before 1984, both the Julian year and the mean tropical year were used by astronomers. In 1898, Simon Newcomb used both in his Tables of the Sun in the form of the Julian century (36 525 days) and the "solar century" ( 36 524 .22 days), a rounded form of 100 mean tropical years of 365.242 198 79 days each according to Newcomb. [ 5 ] However, the mean tropical year is not suitable as a unit of measurement because it varies from year to year by a small amount, 6.14 × 10 −8 days according to Newcomb. [ 5 ] In contrast, the Julian year is defined in terms of the SI unit one second , so is as accurate as that unit and is constant. It approximates both the sidereal year and the tropical year to about ±0.008 days. The Julian year is the basis of the definition of the light-year as a unit of measurement of distance. [ 2 ]
In astronomy, an epoch specifies a precise moment in time. The positions of celestial objects and events, as measured from Earth , change over time, so when measuring or predicting celestial positions, the epoch to which they pertain must be specified. A new standard epoch is chosen about every 50 years.
The standard epoch in use today is Julian epoch J2000.0 . It is exactly 12:00 TT (close to but not exactly Greenwich mean noon) on January 1, 2000 in the Gregorian ( not Julian) calendar. Julian within its name indicates that other Julian epochs can be a number of Julian years of 365.25 days each before or after J2000.0. For example, the future epoch J2100.0 will be exactly 36,525 days (one Julian century) from J2000.0 at 12:00 TT on January 1, 2100 (the dates will still agree because the Gregorian century 2000–2100 will have the same number of days as a Julian century).
Because Julian years are not exactly the same length as years on the Gregorian calendar, astronomical epochs will diverge noticeably from the Gregorian calendar in a few hundred years. For example, in the next 1000 years, seven days will be dropped from the Gregorian calendar but not from 1000 Julian years, so J3000.0 will be January 8, 3000 12:00 TT .
The Julian year , being a uniform measure of duration, should not be confused with the variable length historical years in the Julian calendar. An astronomical Julian year is never individually numbered. When not using Julian day numbers ( see next §), astronomers follow the same conventional calendars that are accepted in the world community: They use the Gregorian calendar for events since its introduction on October 15, 1582 (or later, depending on country), and the Julian calendar for events before that date, and occasionally other, local calendars when appropriate for a given publication.
A Julian year should not be confused with the Julian day , which is also used in astronomy (more properly called the Julian day number or JDN ). The JDN uniquely specifies a place in time, without becoming bogged down in its date-in-month, week, month, or year in any particular calendar. Despite the similarity of names, there is almost no connection between the Julian day numbers and Julian years .
The Julian day number is a simplified time-keeping system originally intended to ease calculation with historical dates which involve a diversity of local, idiosyncratic calendars. It was adopted by astronomers in the mid-1800s, and identifies each date as the integer number of days that have elapsed since a reference date ( "epoch" ), chosen to precede most, if not all, historical records. A specific time within a day, always using UTC , is specified via a decimal fraction. | https://en.wikipedia.org/wiki/Julian_year_(astronomy) |
The Julia olefination (also known as the Julia–Lythgoe olefination) is the chemical reaction used in organic chemistry of phenyl sulfones (1) with aldehydes (or ketones ) to give alkenes (olefins)(3) after alcohol functionalization and reductive elimination using sodium amalgam [1] [2] or SmI 2 . [3] The reaction is named after the French chemist Marc Julia .
The utility of this connective olefination reaction arises from its versatility, its wide functional group tolerance, and the mild reaction conditions under which the reaction proceeds.
All four steps can be carried out in a single reaction vessel, and use of R 3 X is optional. However, purification of the sulfone intermediate 2 leads to higher yield and purity. Most often R 3 is acetyl or benzoyl , with acetic anhydride or benzoyl chloride used in the preparation of 2.
In 1973, Marc Julia and Jean-Marc Paris reported a novel olefin synthesis in which β-acyloxysulfones were reductively eliminated to the corresponding di-, tri-, or tetrasubstituted alkenes. [4] Basil Lythgoe and Philip J. Kocienski explored the scope and limitation of the reaction, and today this olefination is formally known as the Julia-Lythgoe olefination. [5] The reaction involves the addition of a sulfonyl-stabilized carbanion to a carbonyl compound, followed by elimination to form an alkene. In the initial versions of the reactions, the elimination was done under reductive conditions. More recently, a modified version that avoids this step was developed by Sylvestre Julia (no relation to Marc). [ 1 ] The former version is sometimes referred to as the Julia-Lythgoe olefination, whereas the latter is called the Julia-Kocienski olefination. In the reductive variant, the adduct is usually acylated and then treated with a reducing agent, such as sodium amalgam [6] [7] or SmI 2 . [8] Several reviews of these reactions have been published. [9] [10]
The initial steps are straightforward. The phenyl sulfone anion (2) reacts with an aldehyde to form the alkoxide (3). The alkoxide is functionalized with R 3 -X to give the stable intermediate (4). The exact mechanism of the sodium amalgam reduction is unknown but has been shown to proceed through a vinylic radical species (5) [11] . Protonation of the vinylic radical gives the desired product (6).
The stereochemistry of the alkene (6) is independent of the stereochemistry of the sulfone intermediate 4. It is thought that the radical intermediates are able to equilibrate so that the more thermodynamically stable trans-olefin is produced most often. This transformation highly favors formation of the E -alkene. [12]
The modified Julia olefination, also known as the one-pot Julia olefination is a modification of the classical Julia olefination. The replacement of the phenyl sulfones with heteroaryl sulfones greatly alters the reaction pathway. [13] The most popular example is the benzothiazole sulfone. [14] The reaction of the benzothiazole sulfone (1) with lithium diisopropylamide (LDA) gives a metallated benzothiazolyl sulfone, which reacts quickly with aldehydes (or ketones) to give an alkoxide intermediate (2). Unlike the phenyl sulfones, this alkoxide intermediate (2) is more reactive and will undergo a Smiles rearrangement [15] to give the sulfinate salt (4). The sulfinate salt (4) will spontaneously eliminate sulfur dioxide and lithium benzothiazolone (5) producing the desired alkene (6).
Since the benzothiazole variation of the Julia olefination does not involve equilibrating intermediates, the stereochemical outcome is a result of the stereochemistry of the initial carbonyl addition. As a result, this reaction often generates a mixture of alkene stereoisomers.
The Julia–Kocienski Olefination, a further refinement of the Modified Julia olefination, offers very good E -selectivity. In the Julia–Kocienski olefination [16] the alkylating agent is a tetrazole . It proceeds with the same mechanism as the benzothiazole sulfone above. The high E -selectivity of the Julia–Kocienski olefination is the result of kinetically controlled diastereoselective addition of metalated 1-phenyl-1H-tetrazol-5-yl (PT) sulfones to nonconjugated aldehydes. This yields anti-β-alkoxysulfones which stereospecifically decompose to the E -alkenes. [17] In one adaptation, [18] with t-butyltetrazoylmethyl sulfone the reaction conditions are either sodium bis(trimethylsilyl)amide at −70 °C in tetrahydrofuran or caesium carbonate at +70 °C. This reaction is named after Philip J. Kocienski for his modification to the Julia olefination.
The Julia or modified Julia olefination reaction is a powerful and versatile synthetic transformation, widely utilized in the construction of complex natural products with excellent control of geometrical isomerism.
Pterostilbene is a stilbenoid chemically related to resveratrol. It belongs to the group of phytoalexins, agents produced by plants to fight infections. [19] Pterostilbene is a naturally occurring dimethyl ether analog of resveratrol. It is believed that the compound also has anti-diabetic properties, but so far very little has been studied on this issue.
Compared to the Wittig , Wittig-Horner, Perkin , or transition-metal-catalyzed reactions to synthesize pterostilebene, the Julia olefination offers a simple, economical alternative method for preparation of pterostilbene. [20] [21]
One adaptation of the Julia-Kocienski olefination gives the synthesis of the stilbenoid resveratrol , a natural compound found in common foods like grapes, wines and nuts. Resveratrol is a biologically important stilbenoid which has been suggested to have many health benefits. The Julia-Kocienski olefination serves as a powerful reaction in the synthesis of resveratrol analogues with 3,5-bis(trifluoromethyl)phenyl sulfones. The following schematic displays the general scheme for synthesizing resveratrol analogues, where R 2 is an aryl group. [22]
In the asymmetric total synthesis of (−)-callystatin A by Amos Smith , two separate Julia olefinations were used to append two E -alkene moieties. [23] (−)-callystatin A is a member of the leptomycin family of antibiotics. The following schematic displays the Julia-Kocienski olefination used to achieve the precursor to the natural product, as indicated by use of the PT-sulfone. | https://en.wikipedia.org/wiki/Julia–Kocienski_olefination |
Julie Elizabeth Gough is a Professor of Biomaterials and Tissue Engineering at The University of Manchester . She specializes on controlling cellular responses at the cell-biomaterial interface by engineering defined surfaces for mechanically sensitive connective tissues.
Gough is a cell biologist. She studied cell- and immunobiology, and molecular pathology and toxicology at the University of Leicester , graduating with a BSc in 1993 and an MSc in 1994, respectively. She continued her doctoral studies at the University of Nottingham , earning her PhD in Biomaterials in 1998. Between 1998 and 2002, she furthered her studies at both Nottingham and Imperial College London as a postdoctoral fellow working on novel composites and bioactive glasses for bone repair. [ 1 ]
Gough joined the School of Materials , Faculty of Science and Engineering at The University of Manchester, as a lecturer in 2002. She was quickly promoted to Senior lecturer and Reader in 2006 and 2010, respectively. [ citation needed ]
From 2012 to 2013 she was a Royal Academy of Engineering/Leverhulme Trust Senior Research Fellow. [ 2 ] Gough was made full Professor in 2014.
Since then, she has continued her research in tissue engineering of mechanically sensitive connective tissues such as bone, cartilage, skeletal muscle and the intervertebral disc. This includes analysis and control of cells such as osteoblasts, chondrocytes, fibroblasts, keratinocytes, myoblasts and macrophages on a variety of materials and scaffolds. Her research also involves the development of scaffolds for tissue repair using novel hydrogels and magnesium alloys as various porous and fibrous materials. Gough has worked on the advisory board of the journal Biomaterials Science , [ 3 ] and as part of the local organising committee for the World Biomaterials Congress. [ 4 ]
This article about a biologist from the United Kingdom is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Julie_Elizabeth_Gough |
Julio M. Ottino is a chemical engineer known for his research in fluid dynamics , chaos and mixing, and complex systems. [ 1 ] He is also an artist, author, and educator. [ 2 ] He is currently the Distinguished Robert R. McCormick Institute Professor and Walter P. Murphy Professor of chemical and biological engineering at Northwestern University , and is also a professor of management and organizations in the Kellogg School of Management .
He previously served as the dean of the McCormick School of Engineering and Applied Science at Northwestern University from 2005-2023. [ 3 ]
Ottino was born in La Plata, Argentina . Growing up with twin interests in art and science, he received a degree in chemical engineering from the National University of La Plata in 1974. After this, while drafted as an officer in the Argentinean Navy , [ 4 ] he mounted a solo art exhibit with his friend, Dane McRae. Immediately after finishing a two-year term in the Navy, he got married and moved to the United States for graduate school in chemical engineering at the University of Minnesota , where he received his PhD in 1979. [ 5 ]
After his PhD, Ottino held faculty positions at University of Massachusetts , Amherst and held visiting appointments at Caltech , Stanford , and the University of Minnesota before joining Northwestern in 1991.
He was chair of Northwestern ’s Department of Chemical Engineering from 1992 to 2000 and was founder and co-director of NICO, the Northwestern Institute for Complex Systems. In 2005, he became dean of Northwestern’s McCormick School of Engineering. As dean, he developed the whole-brain engineering approach [ 6 ] to research and education, integrating both left-brain analysis and right brain creativity through design, entrepreneurship, and leadership and personal development. [ 7 ]
He created university-wide centers and initiatives, including the Segal Design Institute and the Farley Center for Entrepreneurship and Innovation. [ 8 ]
In education, he launched several new master’s degrees programs in analytics , artificial intelligence , robotics , and energy and sustainability. At the undergraduate level, he made the first-year Design Thinking and Communication course a centerpiece of the engineering education experience. He was instrumental in developing several cross-school initiatives, including the NUvention series of courses, which brought together university-wide multidisciplinary teams to create and launch startups, and the Bay Area Immersion program, which educates students at the intersection of design, technology, and digital media. [ 4 ]
He was also instrumental in developing more education and programming at the intersection of fine arts. With the Block Museum, he developed the Artist-at-Large and the Art + Engineering program. He partnered with the Art Institute of Chicago to facilitate the creation of the Center for Scientific Studies in the Arts and to create joint courses such as "Data as Art." [ 7 ]
During his tenure, applications to the engineering school quadrupled, and research funding doubled. [ 3 ] In 2017, he was awarded the Bernard M. Gordon Prize for Innovation in Engineering and Technology Education [ 9 ] from the National Academy of Engineering for developing and implementing whole-brain engineering.
In 2022, his book The Nexus: Augmented Thinking for a Complex World – The New Convergence of Art, Technology, and Science , [ 10 ] co-authored with Bruce Mau , was published by MIT Press .
Ottino's experimental and theoretical work in chemical engineering connected the fields of chaos and fluid mixing. For the first 10 years of his career, Ottino's principal focus was on fluid mixing. [ 11 ] He established the scientific basis of mixing and developed mathematical frameworks that showed flows can produce stretching and folding that creates chaotic motion and effective mixing. He has extended this foundational knowledge to applications including microfluidics, materials processing, and CO2 capture. [ 12 ] Recently, Ottino turned his attention to the mixing and segregation of granular materials, [ 13 ] exploiting the mathematics of piecewise isometries. [ 14 ]
His research has been featured in articles and on the covers of Nature , [ 11 ] Science , [ 15 ] Scientific American [ 16 ] , the Proceedings of the National Academy of Sciences of the USA [ 17 ] and other publications and has impacted fields such as complex systems, microfluidics, geophysical sciences, and nonlinear dynamics and chaos. He has directed more than 65 PhD theses and is the author of nearly 250 papers and three books. | https://en.wikipedia.org/wiki/Julio_M._Ottino |
The Juliá–Colonna epoxidation is an asymmetric poly- leucine catalyzed nucleophilic epoxidation of electron deficient olefins in a triphasic system . The reaction was reported by Sebastian Juliá at the Chemical Institute of Sarriá in 1980, [ 1 ] with further elaboration by both Juliá and Stefano Colonna (Istituto di Chimica Industriale dell'Università, Milan, Italy). [ 2 ]
In the original triphasic protocol, the chalcone substrate is soluble in the organic phase, generally toluene or carbon tetrachloride . The alkaline hydrogen peroxide oxidant is soluble primarily in the aqueous phase, and the reaction occurs at the insoluble polymer layer at the interface of the two phases. Alternative biphasic and monophasic protocols have been developed with increased substrate accessibility and reaction rate. [ 3 ] [ 4 ]
The efficient enantioselective catalytic epoxidation under mild conditions is of great synthetic utility. Not only are epoxides effective synthons for a range of transformations, they have a significant presence in natural products structures. Furthermore, the reaction has been effectively scaled up to industrially useful levels, with work conducted notably by Bayer and Evonik . Finally, the enzyme-like activity of the poly-amino acid segments is suggestive of a role of the reaction in the prebiotic origin of life . [ 5 ] [ 6 ]
The Juliá–Colonna epoxidation is an asymmetric nucleophilic epoxidation of electron-deficient olefins such as α,β-unsaturated ketones . The general mechanism shown in Figure 2 applies to all nucleophilic epoxidations but is controlled in this reaction by the poly-leucine catalyst.
The hydroperoxide anion and chalcone assemble in a complex with the poly-leucine catalyst before reacting to form a peroxide enolate intermediate. The intermediate subsequently closes, as controlled by the catalyst structure, to form the epoxide product stereoselectively.
The poly-leucine strands demonstrate enzyme-like kinetics with a first-order dependence on and eventual saturation with both the hydroperoxide anion (K M = 30 mM) and the olefin substrate (K M =110 mM.) Kinetic study suggests that the reaction proceeds by random steady-state formation of a ternary (polyleucine+hydroperoxide anion+olefin) complex . Both substrates must bind prior to reaction, and while either may bind first, initial hydroperoxide binding is kinetically preferred. The rapid equilibrium enabling complex formation is followed by the rate-limiting formation of the peroxide enolate (Figure 3). [ 5 ] [ 8 ]
All of the reactants associate with the polyleucine catalyst prior to reaction to form the hydroperoxide enolate intermediate. The catalyst orients the reactants and, even more significantly, the peroxide enolate intermediate by a series of hydrogen bonding interactions with the four N-terminal amino groups in the poly-leucine α-helix . While other models have been proposed, [ 9 ] computations by Kelly et al. have suggested that the NH-2, NH-3, and NH-4 form an isosceles triangle available for hydrogen bonding as an intermediate-stabilizing oxyanion hole . While olefin binding to either the endo or exo face of the helix is sterically allowed, only endo binding orients the NH-4 group to bind with the hydroperoxide moiety allowing for hydroxide displacement in the final reaction step (Figure 4). [ 7 ]
Enantioselectivity is maximized by poly-amino acid sequences containing the greatest α-helical content; these include poly- leucine and poly- alanine . [ 1 ] Both poly-L- and poly-D-amino acids are available and cause the opposite stereoinduction. [ 10 ]
The original poly-leucine catalysts were formed by reacting leucine-N-carboxyanhydrides with an initiator such as an amine, an alcohol or water (Figure 5). [ 2 ] In triphasic systems, the polymer catalyst must be soaked in the organic solvent and peroxide solution to generate a gel prior to reaction. [ 11 ] –
Especially in biphasic systems, reaction time may be reduced and enantioselectivity increased by activating the catalyst with NaOH prior to reaction. Furthermore, in biphasic systems the polymer may be immobilized on polystyrene , polyethylene glycol (PEG), or silica gel and formed into a paste. [ 4 ]
The active component of the catalyst assumes an α-helical structure where the four to five N-terminal residues are actively involved in catalysis. While active catalysts have been generated from scalemic leucine, consistent enantiomeric content must be maintained through the N-terminal region to give appropriate handedness to the structure. [ 10 ] While the greatest enantioselectivity was originally observed when n=30 residues, [ 2 ] a 10-mer leucine polypeptide is of sufficient length to provide significant enantioselectivity [ 10 ] Following improvement of the original procedure, greater enantioselectivity has been observed for lower molecular weight polymers, presumably due to the greater number of N-termini available per mass used. [ 4 ]
The Juliá–Colonna epoxidation of electron-deficient olefins was originally demonstrated with chalcones, but it was soon extended to other systems with electron withdrawing moieties such as α,β-unsaturated ketones, esters, and amides. [ 1 ] [ 2 ] The reaction has also demonstrated efficiency with sulfone substrates, and the scope of the reaction is being expanded with further methodological investigation. [ 12 ]
Several classes of substrates, however, are not suitable for the Juliá–Colonna Epoxidation. These include: [ 10 ]
The nucleophilic epoxidation is naturally complementary in scope to electrophilic epoxidations such as the Sharpless epoxidation and Jacobsen epoxidation .
The stereoinduction of the Juliá–Colonna epoxidation is dependent on the α-helical secondary structure of the poly-leucine catalyst. While the consistent stereochemistry of the N-terminal amino acids is necessary for this induction, even a 10-mer leucine polypeptide is of sufficient length to provide significant enantioselectivity. [ 10 ]
This dependence solely on the N-terminal region of the helix is most pronounced in enantioselective stereoinduction by scalemic catalysts. Even a 40% enantiomeric excess of L vs. D-leucine in catalyst formation can yield the same enantiomeric enriched epoxide as the enantiopure catalyst. The relationship between catalyst and product enantiopurity can be closely approximated with a Bernoullian statistical model: ee n =(L n -D n )/(L n +D n ) where L and D are the proportions of L- and D-leucine used to generate the catalytic polymers and n is the length of the catalytic component. [ 5 ] [ 6 ]
Chiral amino acids, including leucine, have been generated in electrical discharge experiments designed to mimic the prebiotic conditions on Earth, and they have been found in scalemic mixtures in meteorites. It has been suggested that poly-amino acid fragments analogous to the Juliá–Colonna catalyst may have been initiated by imidazole or cyanide derivatives, and the resulting fragments may have played a catalytic role in the origin of enantiomeric enrichment ubiquitous in life today. [ 5 ]
Silica -grafted polyleucine has been shown to effectively catalyze epoxidation of α,β-unsaturated aromatic ketones. The silica graft allows for the catalyst to be easily recovered with only mild loss of activity and is particularly useful for scale-up reactions. [ 13 ]
For the alternative biphasic protocol, the olefin substrate is dissolved in tetrahydrofuran (THF) along with the urea hydrogen peroxide (UHP) oxidant and a tertiary amine base such as 8-diazabicyclo[5.4.0]undec-7-ene (DBU.) The immobilized polymer catalyst forms a paste which serves as the reaction site. The two phase reaction conditions extended the range of enones to which the reaction could be applied. [ 3 ]
A soluble initiator O,O′-bis(2-aminoethyl)polyethylene glycol (diaminoPEG) for poly-leucine assembly was utilized to generate a THF-soluble triblock polymer . Utilization of this catalyst in homogeneous reaction conditions enabled marked extension of the methodology to α,β-unsaturated ketones , dienes , and bis -dienes. [ 4 ]
Addition of tetrabutylammonium bromide as a phase transfer catalyst dramatically increases the rate of reaction. The co-catalyst is presumed to increase the concentration of the peroxide oxidant in the organic phase enabling more efficient access to the reactive ternary complex. [ 14 ] These conditions were developed for application to two phase systems but also function for three phase systems and have been utilized up to the 100g scale [ 5 ] [ 12 ]
Immobilized catalysts have been used in membrane reactors and are being investigated for application to continuous flow fixed bed reactors. [ 11 ]
Adger et al. utilized the biphasic Juliá–Colonna epoxidation with immobilized poly-L-leucine (I-PLL) and urea hydrogen peroxide (UHP), and 8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the key step in the efficient synthesis of Diltiazem (Figure 6.) Diltiazem is a commercially available pharmaceutical which acts as a calcium channel blocker. [ 11 ]
Cappi et al. utilized the Juliá–Colonna epoxidation with PEG-immobilized poly-L-leucine (PEG-PLL) and DABCO hydrogen peroxide (DABCO-H 2 O 2 ) or urea hydrogen peroxide (UHP) in a miniature fixed-bed continuous flow reactor system (Figure 7.) This protocol was exploited to synthesize (+)-clausenamide as a proof of concept in the development of the novel reaction protocol; (+)-clausenamide exhibits anti-amnesiac and hepatoprotective activity. [ 15 ]
Chen et al. utilized the biphasic Juliá–Colonna Epoxidation protocol with urea hydrogen peroxide (UHP), poly-L-leucine (PLL), and 8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a key step in the synthesis of a family of styryl lactones isolated from Goniothalamus giganteus (Figure 8.) These compounds, including (+)-goniotriol 7, (+)-goniofufurone 8, (+)-8-acetylgoniotriol 9 and gonio-pypyrone, have demonstrated cytotoxic activity against human tumor cells. [ 16 ] | https://en.wikipedia.org/wiki/Juliá–Colonna_epoxidation |
In computing and electronic systems, binary-coded decimal ( BCD ) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits , usually four or eight. Sometimes, special bit patterns are used for a sign or other indications (e.g. error or overflow).
In byte -oriented systems (i.e. most modern computers), the term unpacked BCD [ 1 ] usually implies a full byte for each digit (often including a sign), whereas packed BCD typically encodes two digits within a single byte by taking advantage of the fact that four bits are enough to represent the range 0 to 9. The precise four-bit encoding, however, may vary for technical reasons (e.g. Excess-3 ).
The ten states representing a BCD digit are sometimes called tetrades [ 2 ] [ 3 ] (the nibble typically needed to hold them is also known as a tetrade) while the unused, don't care -states are named pseudo-tetrad(e)s [ de ] , [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] pseudo-decimals , [ 3 ] or pseudo-decimal digits . [ 9 ] [ 10 ] [ nb 1 ]
BCD's main virtue, in comparison to binary positional systems , is its more accurate representation and rounding of decimal quantities, as well as its ease of conversion into conventional human-readable representations. Its principal drawbacks are a slight increase in the complexity of the circuits needed to implement basic arithmetic as well as slightly less dense storage.
BCD was used in many early decimal computers , and is implemented in the instruction set of machines such as the IBM System/360 series and its descendants, Digital Equipment Corporation 's VAX , the Burroughs B1700 , and the Motorola 68000 -series processors.
BCD per se is not as widely used as in the past, and is unavailable or limited in newer instruction sets (e.g., ARM ; x86 in long mode ). However, decimal fixed-point and decimal floating-point formats are still important and continue to be used in financial, commercial, and industrial computing, where the subtle conversion and fractional rounding errors that are inherent in binary floating point formats cannot be tolerated. [ 11 ]
BCD takes advantage of the fact that any one decimal numeral can be represented by a four-bit pattern. An obvious way of encoding digits is Natural BCD (NBCD), where each decimal digit is represented by its corresponding four-bit binary value, as shown in the following table. This is also called "8421" encoding.
This scheme can also be referred to as Simple Binary-Coded Decimal ( SBCD ) or BCD 8421 , and is the most common encoding. [ 12 ] Others include the so-called "4221" and "7421" encoding – named after the weighting used for the bits – and " Excess-3 ". [ 13 ] For example, the BCD digit 6, 0110'b in 8421 notation, is 1100'b in 4221 (two encodings are possible), 0110'b in 7421, while in Excess-3 it is 1001'b ( 6 + 3 = 9 {\displaystyle 6+3=9} ).
The following table represents decimal digits from 0 to 9 in various BCD encoding systems. In the headers, the " 8 4 2 1 " indicates the weight of each bit. In the fifth column ("BCD 8 4 −2 −1"), two of the weights are negative. Both ASCII and EBCDIC character codes for the digits, which are examples of zoned BCD, are also shown.
As most computers deal with data in 8-bit bytes , it is possible to use one of the following methods to encode a BCD number:
As an example, encoding the decimal number 91 using unpacked BCD results in the following binary pattern of two bytes:
In packed BCD, the same number would fit into a single byte:
Hence the numerical range for one unpacked BCD byte is zero through nine inclusive, whereas the range for one packed BCD byte is zero through ninety-nine inclusive.
To represent numbers larger than the range of a single byte any number of contiguous bytes may be used. For example, to represent the decimal number 12345 in packed BCD, using big-endian format, a program would encode as follows:
Here, the most significant nibble of the most significant byte has been encoded as zero, so the number is stored as 012345 (but formatting routines might replace or remove leading zeros). Packed BCD is more efficient in storage usage than unpacked BCD; encoding the same number (with the leading zero) in unpacked format would consume twice the storage.
Shifting and masking operations are used to pack or unpack a packed BCD digit. Other bitwise operations are used to convert a numeral to its equivalent bit pattern or reverse the process.
Some computers whose words are multiples of an octet (8-bit byte), for example contemporary IBM mainframe systems, support packed BCD (or packed decimal [ 38 ] ) numeric representations, in which each nibble represents either a decimal digit or a sign. [ nb 8 ] Packed BCD has been in use since at least the 1960s and is implemented in all IBM mainframe hardware since then. Most implementations are big endian , i.e. with the more significant digit in the upper half of each byte, and with the leftmost byte (residing at the lowest memory address) containing the most significant digits of the packed decimal value. The lower nibble of the rightmost byte is usually used as the sign flag, although some unsigned representations lack a sign flag.
As an example, a 4-byte value consists of 8 nibbles, wherein the upper 7 nibbles store the digits of a 7-digit decimal value, and the lowest nibble indicates the sign of the decimal integer value. Standard sign values are 1100 ( hex C) for positive (+) and 1101 (D) for negative (−). This convention comes from the zone field for EBCDIC characters and the signed overpunch representation.
Other allowed signs are 1010 (A) and 1110 (E) for positive and 1011 (B) for negative. IBM System/360 processors will use the 1010 (A) and 1011 (B) signs if the A bit is set in the PSW, for the ASCII-8 standard that never passed. Most implementations also provide unsigned BCD values with a sign nibble of 1111 (F). [ 39 ] [ 40 ] [ 41 ] ILE RPG uses 1111 (F) for positive and 1101 (D) for negative. [ 42 ] These match the EBCDIC zone for digits without a sign overpunch. In packed BCD, the number 127 is represented by 0001 0010 0111 1100 (127C) and −127 is represented by 0001 0010 0111 1101 (127D). Burroughs systems used 1101 (D) for negative, and any other value is considered a positive sign value (the processors will normalize a positive sign to 1100 (C)).
No matter how many bytes wide a word is, there is always an even number of nibbles because each byte has two of them. Therefore, a word of n bytes can contain up to (2 n )−1 decimal digits, which is always an odd number of digits. A decimal number with d digits requires 1 / 2 ( d +1) bytes of storage space.
For example, a 4-byte (32-bit) word can hold seven decimal digits plus a sign and can represent values ranging from ±9,999,999. Thus the number −1,234,567 is 7 digits wide and is encoded as:
Like character strings, the first byte of the packed decimal – that with the most significant two digits – is usually stored in the lowest address in memory, independent of the endianness of the machine.
In contrast, a 4-byte binary two's complement integer can represent values from −2,147,483,648 to +2,147,483,647.
While packed BCD does not make optimal use of storage (using about 20% more memory than binary notation to store the same numbers), conversion to ASCII , EBCDIC, or the various encodings of Unicode is made trivial, as no arithmetic operations are required. The extra storage requirements are usually offset by the need for the accuracy and compatibility with calculator or hand calculation that fixed-point decimal arithmetic provides. Denser packings of BCD exist which avoid the storage penalty and also need no arithmetic operations for common conversions.
Packed BCD is supported in the COBOL programming language as the "COMPUTATIONAL-3" (an IBM extension adopted by many other compiler vendors) or "PACKED-DECIMAL" (part of the 1985 COBOL standard) data type. It is supported in PL/I as "FIXED DECIMAL". Beside the IBM System/360 and later compatible mainframes, packed BCD is implemented in the native instruction set of the original VAX processors from Digital Equipment Corporation and some models of the SDS Sigma series mainframes, and is the native format for the Burroughs Medium Systems line of mainframes (descended from the 1950s Electrodata 200 series ).
Ten's complement representations for negative numbers offer an alternative approach to encoding the sign of packed (and other) BCD numbers. In this case, positive numbers always have a most significant digit between 0 and 4 (inclusive), while negative numbers are represented by the 10's complement of the corresponding positive number.
As a result, this system allows for 32-bit packed BCD numbers to range from −50,000,000 to +49,999,999, and −1 is represented as 99999999. (As with two's complement binary numbers, the range is not symmetric about zero.)
Fixed-point decimal numbers are supported by some programming languages (such as COBOL and PL/I). These languages allow the programmer to specify an implicit decimal point in front of one of the digits.
For example, a packed decimal value encoded with the bytes 12 34 56 7C represents the fixed-point value +1,234.567 when the implied decimal point is located between the fourth and fifth digits:
The decimal point is not actually stored in memory, as the packed BCD storage format does not provide for it. Its location is simply known to the compiler, and the generated code acts accordingly for the various arithmetic operations.
If a decimal digit requires four bits, then three decimal digits require 12 bits. However, since 2 10 (1,024) is greater than 10 3 (1,000), if three decimal digits are encoded together, only 10 bits are needed. Two such encodings are Chen–Ho encoding and densely packed decimal (DPD). The latter has the advantage that subsets of the encoding encode two digits in the optimal seven bits and one digit in four bits, as in regular BCD.
Some implementations, for example IBM mainframe systems, support zoned decimal numeric representations. Each decimal digit is stored in one 8-bit [ nb 9 ] byte, with the lower four bits encoding the digit in BCD form. The upper four [ nb 10 ] bits, called the "zone" bits, are usually set to a fixed value so that the byte holds a character value corresponding to the digit, or to values representing plus or minus. EBCDIC [ nb 11 ] systems use a zone value of 1111 2 (F 16 ), yielding F0 16 -F9 16 , the codes for "0" through "9", a zone value of 1100 2 (C 16 ) for positive, yielding C0 16 -C9 16 , the codes for "{" through "I" and a zone value of 1110 2 (D 16 ) for negative, yielding D0 16 -D9 16 , the codes for the characters "}" through "R". Similarly, ASCII systems use a zone value of 0011 (hex 3), giving character codes 30 to 39 (hex).
For signed zoned decimal values, the rightmost (least significant) zone nibble holds the sign digit, which is the same set of values that are used for signed packed decimal numbers (see above). Thus a zoned decimal value encoded as the hex bytes F1 F2 D3 represents the signed decimal value −123:
(*) Note: These characters vary depending on the local character code page setting.
Some languages (such as COBOL and PL/I) directly support fixed-point zoned decimal values, assigning an implicit decimal point at some location between the decimal digits of a number.
For example, given a six-byte signed zoned decimal value with an implied decimal point to the right of the fourth digit, the hex bytes F1 F2 F7 F9 F5 C0 represent the value +1,279.50:
It is possible to perform addition by first adding in binary, and then converting to BCD afterwards. Conversion of the simple sum of two digits can be done by adding 6 (that is, 16 − 10) when the five-bit result of adding a pair of digits has a value greater than 9. The reason for adding 6 is that there are 16 possible 4-bit BCD values (since 2 4 = 16), but only 10 values are valid (0000 through 1001). For example:
10001 is the binary, not decimal, representation of the desired result, but the most significant 1 (the "carry") cannot fit in a 4-bit binary number. In BCD as in decimal, there cannot exist a value greater than 9 (1001) per digit. To correct this, 6 (0110) is added to the total, and then the result is treated as two nibbles:
The two nibbles of the result, 0001 and 0111, correspond to the digits "1" and "7". This yields "17" in BCD, which is the correct result.
This technique can be extended to adding multiple digits by adding in groups from right to left, propagating the second digit as a carry, always comparing the 5-bit result of each digit-pair sum to 9. Some CPUs provide a half-carry flag to facilitate BCD arithmetic adjustments following binary addition and subtraction operations. The Intel 8080 , the Zilog Z80 and the CPUs of the x86 family provide the opcode DAA (Decimal Adjust Accumulator).
Subtraction is done by adding the ten's complement of the subtrahend to the minuend . To represent the sign of a number in BCD, the number 0000 is used to represent a positive number , and 1001 is used to represent a negative number . The remaining 14 combinations are invalid signs. To illustrate signed BCD subtraction, consider the following problem: 357 − 432.
In signed BCD, 357 is 0000 0011 0101 0111. The ten's complement of 432 can be obtained by taking the nine's complement of 432, and then adding one. So, 999 − 432 = 567, and 567 + 1 = 568. By preceding 568 in BCD by the negative sign code, the number −432 can be represented. So, −432 in signed BCD is 1001 0101 0110 1000.
Now that both numbers are represented in signed BCD, they can be added together:
Since BCD is a form of decimal representation, several of the digit sums above are invalid. In the event that an invalid entry (any BCD digit greater than 1001) exists, 6 is added to generate a carry bit and cause the sum to become a valid entry. So, adding 6 to the invalid entries results in the following:
Thus the result of the subtraction is 1001 1001 0010 0101 (−925). To confirm the result, note that the first digit is 9, which means negative. This seems to be correct since 357 − 432 should result in a negative number. The remaining nibbles are BCD, so 1001 0010 0101 is 925. The ten's complement of 925 is 1000 − 925 = 75, so the calculated answer is −75.
If there are a different number of nibbles being added together (such as 1053 − 2), the number with the fewer digits must first be prefixed with zeros before taking the ten's complement or subtracting. So, with 1053 − 2, 2 would have to first be represented as 0002 in BCD, and the ten's complement of 0002 would have to be calculated.
IBM used the terms Binary-Coded Decimal Interchange Code (BCDIC, sometimes just called BCD), for 6-bit alphanumeric codes that represented numbers, upper-case letters and special characters. Some variation of BCDIC alphamerics is used in most early IBM computers, including the IBM 1620 (introduced in 1959), IBM 1400 series , and non- decimal architecture members of the IBM 700/7000 series .
The IBM 1400 series are character-addressable machines, each location being six bits labeled B, A, 8, 4, 2 and 1, plus an odd parity check bit ( C ) and a word mark bit ( M ). For encoding digits 1 through 9 , B and A are zero and the digit value represented by standard 4-bit BCD in bits 8 through 1 . For most other characters bits B and A are derived simply from the "12", "11", and "0" "zone punches" in the punched card character code, and bits 8 through 1 from the 1 through 9 punches. A "12 zone" punch set both B and A , an "11 zone" set B , and a "0 zone" (a 0 punch combined with any others) set A . Thus the letter A , which is (12,1) in the punched card format, is encoded (B,A,1) . The currency symbol $ , (11,8,3) in the punched card, was encoded in memory as (B,8,2,1) . This allows the circuitry to convert between the punched card format and the internal storage format to be very simple with only a few special cases. One important special case is digit 0 , represented by a lone 0 punch in the card, and (8,2) in core memory. [ 43 ]
The memory of the IBM 1620 is organized into 6-bit addressable digits, the usual 8, 4, 2, 1 plus F , used as a flag bit and C , an odd parity check bit. BCD alphamerics are encoded using digit pairs, with the "zone" in the even-addressed digit and the "digit" in the odd-addressed digit, the "zone" being related to the 12 , 11 , and 0 "zone punches" as in the 1400 series. Input/output translation hardware converted between the internal digit pairs and the external standard 6-bit BCD codes.
In the decimal architecture IBM 7070 , IBM 7072 , and IBM 7074 alphamerics are encoded using digit pairs (using two-out-of-five code in the digits, not BCD) of the 10-digit word, with the "zone" in the left digit and the "digit" in the right digit. Input/output translation hardware converted between the internal digit pairs and the external standard 6-bit BCD codes.
With the introduction of System/360 , IBM expanded 6-bit BCD alphamerics to 8-bit EBCDIC, allowing the addition of many more characters (e.g., lowercase letters). A variable length packed BCD numeric data type is also implemented, providing machine instructions that perform arithmetic directly on packed decimal data.
On the IBM 1130 and 1800 , packed BCD is supported in software by IBM's Commercial Subroutine Package.
Today, BCD data is still heavily used in IBM databases such as IBM Db2 and processors such as z/Architecture and POWER6 and later Power ISA processors. In these products, the BCD is usually zoned BCD (as in EBCDIC or ASCII), packed BCD (two decimal digits per byte), or "pure" BCD encoding (one decimal digit stored as BCD in the low four bits of each byte). All of these are used within hardware registers and processing units, and in software.
The Digital Equipment Corporation VAX series includes instructions that can perform arithmetic directly on packed BCD data and convert between packed BCD data and other integer representations. [ 41 ] The VAX's packed BCD format is compatible with that on IBM System/360 and IBM's later compatible processors. The MicroVAX and later VAX implementations dropped this ability from the CPU but retained code compatibility with earlier machines by implementing the missing instructions in an operating system-supplied software library. This is invoked automatically via exception handling when the defunct instructions are encountered, so that programs using them can execute without modification on the newer machines.
Many processors have hardware support for BCD-encoded integer arithmetic. For example, the 6502 , [ 44 ] [ 45 ] the Motorola 68000 series , [ 46 ] and the x86 series. [ 47 ] The Intel x86 architecture supports a unique 18-digit (ten-byte) BCD format that can be loaded into and stored from the floating point registers, from where computations can be performed. [ 48 ]
In more recent computers such capabilities are almost always implemented in software rather than the CPU's instruction set, but BCD numeric data are still extremely common in commercial and financial applications.
There are tricks for implementing packed BCD and zoned decimal add–or–subtract operations using short but difficult to understand sequences of word-parallel logic and binary arithmetic operations. [ 49 ] For example, the following code (written in C ) computes an unsigned 8-digit packed BCD addition using 32-bit binary operations:
BCD is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit.
This matches much more closely the physical reality of display hardware—a designer might choose to use a series of separate identical seven-segment displays to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing with such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to an overall simpler system than converting to and from binary. Most pocket calculators do all their calculations in BCD.
The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, representing numbers internally in BCD format results in smaller code, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature dedicated arithmetic modes, which assist when writing routines that manipulate BCD quantities. [ 50 ] [ 51 ]
Various BCD implementations exist that employ other representations for numbers. Programmable calculators manufactured by Texas Instruments , Hewlett-Packard , and others typically employ a floating-point BCD format, typically with two or three digits for the (decimal) exponent. The extra bits of the sign digit may be used to indicate special numeric values, such as infinity , underflow / overflow , and error (a blinking display).
Signed decimal values may be represented in several ways. The COBOL programming language, for example, supports five zoned decimal formats, with each one encoding the numeric sign in a different way:
3GPP developed TBCD , [ 53 ] an expansion to BCD where the remaining (unused) bit combinations are used to add specific telephony symbols, [ 54 ] [ 55 ] similar to those in telephone keypad design.
The mentioned 3GPP document defines TBCD-STRING with swapped nibbles in each byte. Bits, octets and digits indexed from 1, bits from the right, digits and octets from the left.
bits 8765 of octet n encoding digit 2 n
bits 4321 of octet n encoding digit 2( n – 1) + 1
Meaning number 1234 , would become 21 43 in TBCD.
This format is used in modern mobile telephony to send dialed numbers, as well as operator ID (the MCC/MNC tuple), IMEI , IMSI (SUPI), et.c. [ 56 ] [ 57 ]
If errors in representation and computation are more important than the speed of conversion to and from display, a scaled binary representation may be used, which stores a decimal number as a binary-encoded integer and a binary-encoded signed decimal exponent. For example, 0.2 can be represented as 2 × 10 −1 .
This representation allows rapid multiplication and division, but may require shifting by a power of 10 during addition and subtraction to align the decimal points. It is appropriate for applications with a fixed number of decimal places that do not then require this adjustment—particularly financial applications where 2 or 4 digits after the decimal point are usually enough. Indeed, this is almost a form of fixed point arithmetic since the position of the radix point is implied.
The Hertz and Chen–Ho encodings provide Boolean transformations for converting groups of three BCD-encoded digits to and from 10-bit values [ nb 1 ] that can be efficiently encoded in hardware with only 2 or 3 gate delays. Densely packed decimal (DPD) is a similar scheme [ nb 1 ] that is used for most of the significand , except the lead digit, for one of the two alternative decimal encodings specified in the IEEE 754-2008 floating-point standard.
The BIOS in many personal computers stores the date and time in BCD because the MC6818 real-time clock chip used in the original IBM PC AT motherboard provided the time encoded in BCD. This form is easily converted into ASCII for display. [ 58 ] [ 59 ]
The Atari 8-bit computers use a BCD format for floating point numbers. The MOS Technology 6502 processor has a BCD mode for the addition and subtraction instructions. The Psion Organiser 1 handheld computer's manufacturer-supplied software also uses BCD to implement floating point; later Psion models use binary exclusively.
Early models of the PlayStation 3 store the date and time in BCD. This led to a worldwide outage of the console on 1 March 2010. The last two digits of the year stored as BCD were misinterpreted as 16 causing an error in the unit's date, rendering most functions inoperable. This has been referred to as the Year 2010 problem .
In the 1972 case Gottschalk v. Benson , the U.S. Supreme Court overturned a lower court 's decision that had allowed a patent for converting BCD-encoded numbers to binary on a computer.
The decision noted that a patent "would wholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itself". [ 60 ] This was a landmark judgement that determined the patentability of software and algorithms . | https://en.wikipedia.org/wiki/Jump-at-2_code |
In computing and electronic systems, binary-coded decimal ( BCD ) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits , usually four or eight. Sometimes, special bit patterns are used for a sign or other indications (e.g. error or overflow).
In byte -oriented systems (i.e. most modern computers), the term unpacked BCD [ 1 ] usually implies a full byte for each digit (often including a sign), whereas packed BCD typically encodes two digits within a single byte by taking advantage of the fact that four bits are enough to represent the range 0 to 9. The precise four-bit encoding, however, may vary for technical reasons (e.g. Excess-3 ).
The ten states representing a BCD digit are sometimes called tetrades [ 2 ] [ 3 ] (the nibble typically needed to hold them is also known as a tetrade) while the unused, don't care -states are named pseudo-tetrad(e)s [ de ] , [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] pseudo-decimals , [ 3 ] or pseudo-decimal digits . [ 9 ] [ 10 ] [ nb 1 ]
BCD's main virtue, in comparison to binary positional systems , is its more accurate representation and rounding of decimal quantities, as well as its ease of conversion into conventional human-readable representations. Its principal drawbacks are a slight increase in the complexity of the circuits needed to implement basic arithmetic as well as slightly less dense storage.
BCD was used in many early decimal computers , and is implemented in the instruction set of machines such as the IBM System/360 series and its descendants, Digital Equipment Corporation 's VAX , the Burroughs B1700 , and the Motorola 68000 -series processors.
BCD per se is not as widely used as in the past, and is unavailable or limited in newer instruction sets (e.g., ARM ; x86 in long mode ). However, decimal fixed-point and decimal floating-point formats are still important and continue to be used in financial, commercial, and industrial computing, where the subtle conversion and fractional rounding errors that are inherent in binary floating point formats cannot be tolerated. [ 11 ]
BCD takes advantage of the fact that any one decimal numeral can be represented by a four-bit pattern. An obvious way of encoding digits is Natural BCD (NBCD), where each decimal digit is represented by its corresponding four-bit binary value, as shown in the following table. This is also called "8421" encoding.
This scheme can also be referred to as Simple Binary-Coded Decimal ( SBCD ) or BCD 8421 , and is the most common encoding. [ 12 ] Others include the so-called "4221" and "7421" encoding – named after the weighting used for the bits – and " Excess-3 ". [ 13 ] For example, the BCD digit 6, 0110'b in 8421 notation, is 1100'b in 4221 (two encodings are possible), 0110'b in 7421, while in Excess-3 it is 1001'b ( 6 + 3 = 9 {\displaystyle 6+3=9} ).
The following table represents decimal digits from 0 to 9 in various BCD encoding systems. In the headers, the " 8 4 2 1 " indicates the weight of each bit. In the fifth column ("BCD 8 4 −2 −1"), two of the weights are negative. Both ASCII and EBCDIC character codes for the digits, which are examples of zoned BCD, are also shown.
As most computers deal with data in 8-bit bytes , it is possible to use one of the following methods to encode a BCD number:
As an example, encoding the decimal number 91 using unpacked BCD results in the following binary pattern of two bytes:
In packed BCD, the same number would fit into a single byte:
Hence the numerical range for one unpacked BCD byte is zero through nine inclusive, whereas the range for one packed BCD byte is zero through ninety-nine inclusive.
To represent numbers larger than the range of a single byte any number of contiguous bytes may be used. For example, to represent the decimal number 12345 in packed BCD, using big-endian format, a program would encode as follows:
Here, the most significant nibble of the most significant byte has been encoded as zero, so the number is stored as 012345 (but formatting routines might replace or remove leading zeros). Packed BCD is more efficient in storage usage than unpacked BCD; encoding the same number (with the leading zero) in unpacked format would consume twice the storage.
Shifting and masking operations are used to pack or unpack a packed BCD digit. Other bitwise operations are used to convert a numeral to its equivalent bit pattern or reverse the process.
Some computers whose words are multiples of an octet (8-bit byte), for example contemporary IBM mainframe systems, support packed BCD (or packed decimal [ 38 ] ) numeric representations, in which each nibble represents either a decimal digit or a sign. [ nb 8 ] Packed BCD has been in use since at least the 1960s and is implemented in all IBM mainframe hardware since then. Most implementations are big endian , i.e. with the more significant digit in the upper half of each byte, and with the leftmost byte (residing at the lowest memory address) containing the most significant digits of the packed decimal value. The lower nibble of the rightmost byte is usually used as the sign flag, although some unsigned representations lack a sign flag.
As an example, a 4-byte value consists of 8 nibbles, wherein the upper 7 nibbles store the digits of a 7-digit decimal value, and the lowest nibble indicates the sign of the decimal integer value. Standard sign values are 1100 ( hex C) for positive (+) and 1101 (D) for negative (−). This convention comes from the zone field for EBCDIC characters and the signed overpunch representation.
Other allowed signs are 1010 (A) and 1110 (E) for positive and 1011 (B) for negative. IBM System/360 processors will use the 1010 (A) and 1011 (B) signs if the A bit is set in the PSW, for the ASCII-8 standard that never passed. Most implementations also provide unsigned BCD values with a sign nibble of 1111 (F). [ 39 ] [ 40 ] [ 41 ] ILE RPG uses 1111 (F) for positive and 1101 (D) for negative. [ 42 ] These match the EBCDIC zone for digits without a sign overpunch. In packed BCD, the number 127 is represented by 0001 0010 0111 1100 (127C) and −127 is represented by 0001 0010 0111 1101 (127D). Burroughs systems used 1101 (D) for negative, and any other value is considered a positive sign value (the processors will normalize a positive sign to 1100 (C)).
No matter how many bytes wide a word is, there is always an even number of nibbles because each byte has two of them. Therefore, a word of n bytes can contain up to (2 n )−1 decimal digits, which is always an odd number of digits. A decimal number with d digits requires 1 / 2 ( d +1) bytes of storage space.
For example, a 4-byte (32-bit) word can hold seven decimal digits plus a sign and can represent values ranging from ±9,999,999. Thus the number −1,234,567 is 7 digits wide and is encoded as:
Like character strings, the first byte of the packed decimal – that with the most significant two digits – is usually stored in the lowest address in memory, independent of the endianness of the machine.
In contrast, a 4-byte binary two's complement integer can represent values from −2,147,483,648 to +2,147,483,647.
While packed BCD does not make optimal use of storage (using about 20% more memory than binary notation to store the same numbers), conversion to ASCII , EBCDIC, or the various encodings of Unicode is made trivial, as no arithmetic operations are required. The extra storage requirements are usually offset by the need for the accuracy and compatibility with calculator or hand calculation that fixed-point decimal arithmetic provides. Denser packings of BCD exist which avoid the storage penalty and also need no arithmetic operations for common conversions.
Packed BCD is supported in the COBOL programming language as the "COMPUTATIONAL-3" (an IBM extension adopted by many other compiler vendors) or "PACKED-DECIMAL" (part of the 1985 COBOL standard) data type. It is supported in PL/I as "FIXED DECIMAL". Beside the IBM System/360 and later compatible mainframes, packed BCD is implemented in the native instruction set of the original VAX processors from Digital Equipment Corporation and some models of the SDS Sigma series mainframes, and is the native format for the Burroughs Medium Systems line of mainframes (descended from the 1950s Electrodata 200 series ).
Ten's complement representations for negative numbers offer an alternative approach to encoding the sign of packed (and other) BCD numbers. In this case, positive numbers always have a most significant digit between 0 and 4 (inclusive), while negative numbers are represented by the 10's complement of the corresponding positive number.
As a result, this system allows for 32-bit packed BCD numbers to range from −50,000,000 to +49,999,999, and −1 is represented as 99999999. (As with two's complement binary numbers, the range is not symmetric about zero.)
Fixed-point decimal numbers are supported by some programming languages (such as COBOL and PL/I). These languages allow the programmer to specify an implicit decimal point in front of one of the digits.
For example, a packed decimal value encoded with the bytes 12 34 56 7C represents the fixed-point value +1,234.567 when the implied decimal point is located between the fourth and fifth digits:
The decimal point is not actually stored in memory, as the packed BCD storage format does not provide for it. Its location is simply known to the compiler, and the generated code acts accordingly for the various arithmetic operations.
If a decimal digit requires four bits, then three decimal digits require 12 bits. However, since 2 10 (1,024) is greater than 10 3 (1,000), if three decimal digits are encoded together, only 10 bits are needed. Two such encodings are Chen–Ho encoding and densely packed decimal (DPD). The latter has the advantage that subsets of the encoding encode two digits in the optimal seven bits and one digit in four bits, as in regular BCD.
Some implementations, for example IBM mainframe systems, support zoned decimal numeric representations. Each decimal digit is stored in one 8-bit [ nb 9 ] byte, with the lower four bits encoding the digit in BCD form. The upper four [ nb 10 ] bits, called the "zone" bits, are usually set to a fixed value so that the byte holds a character value corresponding to the digit, or to values representing plus or minus. EBCDIC [ nb 11 ] systems use a zone value of 1111 2 (F 16 ), yielding F0 16 -F9 16 , the codes for "0" through "9", a zone value of 1100 2 (C 16 ) for positive, yielding C0 16 -C9 16 , the codes for "{" through "I" and a zone value of 1110 2 (D 16 ) for negative, yielding D0 16 -D9 16 , the codes for the characters "}" through "R". Similarly, ASCII systems use a zone value of 0011 (hex 3), giving character codes 30 to 39 (hex).
For signed zoned decimal values, the rightmost (least significant) zone nibble holds the sign digit, which is the same set of values that are used for signed packed decimal numbers (see above). Thus a zoned decimal value encoded as the hex bytes F1 F2 D3 represents the signed decimal value −123:
(*) Note: These characters vary depending on the local character code page setting.
Some languages (such as COBOL and PL/I) directly support fixed-point zoned decimal values, assigning an implicit decimal point at some location between the decimal digits of a number.
For example, given a six-byte signed zoned decimal value with an implied decimal point to the right of the fourth digit, the hex bytes F1 F2 F7 F9 F5 C0 represent the value +1,279.50:
It is possible to perform addition by first adding in binary, and then converting to BCD afterwards. Conversion of the simple sum of two digits can be done by adding 6 (that is, 16 − 10) when the five-bit result of adding a pair of digits has a value greater than 9. The reason for adding 6 is that there are 16 possible 4-bit BCD values (since 2 4 = 16), but only 10 values are valid (0000 through 1001). For example:
10001 is the binary, not decimal, representation of the desired result, but the most significant 1 (the "carry") cannot fit in a 4-bit binary number. In BCD as in decimal, there cannot exist a value greater than 9 (1001) per digit. To correct this, 6 (0110) is added to the total, and then the result is treated as two nibbles:
The two nibbles of the result, 0001 and 0111, correspond to the digits "1" and "7". This yields "17" in BCD, which is the correct result.
This technique can be extended to adding multiple digits by adding in groups from right to left, propagating the second digit as a carry, always comparing the 5-bit result of each digit-pair sum to 9. Some CPUs provide a half-carry flag to facilitate BCD arithmetic adjustments following binary addition and subtraction operations. The Intel 8080 , the Zilog Z80 and the CPUs of the x86 family provide the opcode DAA (Decimal Adjust Accumulator).
Subtraction is done by adding the ten's complement of the subtrahend to the minuend . To represent the sign of a number in BCD, the number 0000 is used to represent a positive number , and 1001 is used to represent a negative number . The remaining 14 combinations are invalid signs. To illustrate signed BCD subtraction, consider the following problem: 357 − 432.
In signed BCD, 357 is 0000 0011 0101 0111. The ten's complement of 432 can be obtained by taking the nine's complement of 432, and then adding one. So, 999 − 432 = 567, and 567 + 1 = 568. By preceding 568 in BCD by the negative sign code, the number −432 can be represented. So, −432 in signed BCD is 1001 0101 0110 1000.
Now that both numbers are represented in signed BCD, they can be added together:
Since BCD is a form of decimal representation, several of the digit sums above are invalid. In the event that an invalid entry (any BCD digit greater than 1001) exists, 6 is added to generate a carry bit and cause the sum to become a valid entry. So, adding 6 to the invalid entries results in the following:
Thus the result of the subtraction is 1001 1001 0010 0101 (−925). To confirm the result, note that the first digit is 9, which means negative. This seems to be correct since 357 − 432 should result in a negative number. The remaining nibbles are BCD, so 1001 0010 0101 is 925. The ten's complement of 925 is 1000 − 925 = 75, so the calculated answer is −75.
If there are a different number of nibbles being added together (such as 1053 − 2), the number with the fewer digits must first be prefixed with zeros before taking the ten's complement or subtracting. So, with 1053 − 2, 2 would have to first be represented as 0002 in BCD, and the ten's complement of 0002 would have to be calculated.
IBM used the terms Binary-Coded Decimal Interchange Code (BCDIC, sometimes just called BCD), for 6-bit alphanumeric codes that represented numbers, upper-case letters and special characters. Some variation of BCDIC alphamerics is used in most early IBM computers, including the IBM 1620 (introduced in 1959), IBM 1400 series , and non- decimal architecture members of the IBM 700/7000 series .
The IBM 1400 series are character-addressable machines, each location being six bits labeled B, A, 8, 4, 2 and 1, plus an odd parity check bit ( C ) and a word mark bit ( M ). For encoding digits 1 through 9 , B and A are zero and the digit value represented by standard 4-bit BCD in bits 8 through 1 . For most other characters bits B and A are derived simply from the "12", "11", and "0" "zone punches" in the punched card character code, and bits 8 through 1 from the 1 through 9 punches. A "12 zone" punch set both B and A , an "11 zone" set B , and a "0 zone" (a 0 punch combined with any others) set A . Thus the letter A , which is (12,1) in the punched card format, is encoded (B,A,1) . The currency symbol $ , (11,8,3) in the punched card, was encoded in memory as (B,8,2,1) . This allows the circuitry to convert between the punched card format and the internal storage format to be very simple with only a few special cases. One important special case is digit 0 , represented by a lone 0 punch in the card, and (8,2) in core memory. [ 43 ]
The memory of the IBM 1620 is organized into 6-bit addressable digits, the usual 8, 4, 2, 1 plus F , used as a flag bit and C , an odd parity check bit. BCD alphamerics are encoded using digit pairs, with the "zone" in the even-addressed digit and the "digit" in the odd-addressed digit, the "zone" being related to the 12 , 11 , and 0 "zone punches" as in the 1400 series. Input/output translation hardware converted between the internal digit pairs and the external standard 6-bit BCD codes.
In the decimal architecture IBM 7070 , IBM 7072 , and IBM 7074 alphamerics are encoded using digit pairs (using two-out-of-five code in the digits, not BCD) of the 10-digit word, with the "zone" in the left digit and the "digit" in the right digit. Input/output translation hardware converted between the internal digit pairs and the external standard 6-bit BCD codes.
With the introduction of System/360 , IBM expanded 6-bit BCD alphamerics to 8-bit EBCDIC, allowing the addition of many more characters (e.g., lowercase letters). A variable length packed BCD numeric data type is also implemented, providing machine instructions that perform arithmetic directly on packed decimal data.
On the IBM 1130 and 1800 , packed BCD is supported in software by IBM's Commercial Subroutine Package.
Today, BCD data is still heavily used in IBM databases such as IBM Db2 and processors such as z/Architecture and POWER6 and later Power ISA processors. In these products, the BCD is usually zoned BCD (as in EBCDIC or ASCII), packed BCD (two decimal digits per byte), or "pure" BCD encoding (one decimal digit stored as BCD in the low four bits of each byte). All of these are used within hardware registers and processing units, and in software.
The Digital Equipment Corporation VAX series includes instructions that can perform arithmetic directly on packed BCD data and convert between packed BCD data and other integer representations. [ 41 ] The VAX's packed BCD format is compatible with that on IBM System/360 and IBM's later compatible processors. The MicroVAX and later VAX implementations dropped this ability from the CPU but retained code compatibility with earlier machines by implementing the missing instructions in an operating system-supplied software library. This is invoked automatically via exception handling when the defunct instructions are encountered, so that programs using them can execute without modification on the newer machines.
Many processors have hardware support for BCD-encoded integer arithmetic. For example, the 6502 , [ 44 ] [ 45 ] the Motorola 68000 series , [ 46 ] and the x86 series. [ 47 ] The Intel x86 architecture supports a unique 18-digit (ten-byte) BCD format that can be loaded into and stored from the floating point registers, from where computations can be performed. [ 48 ]
In more recent computers such capabilities are almost always implemented in software rather than the CPU's instruction set, but BCD numeric data are still extremely common in commercial and financial applications.
There are tricks for implementing packed BCD and zoned decimal add–or–subtract operations using short but difficult to understand sequences of word-parallel logic and binary arithmetic operations. [ 49 ] For example, the following code (written in C ) computes an unsigned 8-digit packed BCD addition using 32-bit binary operations:
BCD is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit.
This matches much more closely the physical reality of display hardware—a designer might choose to use a series of separate identical seven-segment displays to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing with such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to an overall simpler system than converting to and from binary. Most pocket calculators do all their calculations in BCD.
The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, representing numbers internally in BCD format results in smaller code, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature dedicated arithmetic modes, which assist when writing routines that manipulate BCD quantities. [ 50 ] [ 51 ]
Various BCD implementations exist that employ other representations for numbers. Programmable calculators manufactured by Texas Instruments , Hewlett-Packard , and others typically employ a floating-point BCD format, typically with two or three digits for the (decimal) exponent. The extra bits of the sign digit may be used to indicate special numeric values, such as infinity , underflow / overflow , and error (a blinking display).
Signed decimal values may be represented in several ways. The COBOL programming language, for example, supports five zoned decimal formats, with each one encoding the numeric sign in a different way:
3GPP developed TBCD , [ 53 ] an expansion to BCD where the remaining (unused) bit combinations are used to add specific telephony symbols, [ 54 ] [ 55 ] similar to those in telephone keypad design.
The mentioned 3GPP document defines TBCD-STRING with swapped nibbles in each byte. Bits, octets and digits indexed from 1, bits from the right, digits and octets from the left.
bits 8765 of octet n encoding digit 2 n
bits 4321 of octet n encoding digit 2( n – 1) + 1
Meaning number 1234 , would become 21 43 in TBCD.
This format is used in modern mobile telephony to send dialed numbers, as well as operator ID (the MCC/MNC tuple), IMEI , IMSI (SUPI), et.c. [ 56 ] [ 57 ]
If errors in representation and computation are more important than the speed of conversion to and from display, a scaled binary representation may be used, which stores a decimal number as a binary-encoded integer and a binary-encoded signed decimal exponent. For example, 0.2 can be represented as 2 × 10 −1 .
This representation allows rapid multiplication and division, but may require shifting by a power of 10 during addition and subtraction to align the decimal points. It is appropriate for applications with a fixed number of decimal places that do not then require this adjustment—particularly financial applications where 2 or 4 digits after the decimal point are usually enough. Indeed, this is almost a form of fixed point arithmetic since the position of the radix point is implied.
The Hertz and Chen–Ho encodings provide Boolean transformations for converting groups of three BCD-encoded digits to and from 10-bit values [ nb 1 ] that can be efficiently encoded in hardware with only 2 or 3 gate delays. Densely packed decimal (DPD) is a similar scheme [ nb 1 ] that is used for most of the significand , except the lead digit, for one of the two alternative decimal encodings specified in the IEEE 754-2008 floating-point standard.
The BIOS in many personal computers stores the date and time in BCD because the MC6818 real-time clock chip used in the original IBM PC AT motherboard provided the time encoded in BCD. This form is easily converted into ASCII for display. [ 58 ] [ 59 ]
The Atari 8-bit computers use a BCD format for floating point numbers. The MOS Technology 6502 processor has a BCD mode for the addition and subtraction instructions. The Psion Organiser 1 handheld computer's manufacturer-supplied software also uses BCD to implement floating point; later Psion models use binary exclusively.
Early models of the PlayStation 3 store the date and time in BCD. This led to a worldwide outage of the console on 1 March 2010. The last two digits of the year stored as BCD were misinterpreted as 16 causing an error in the unit's date, rendering most functions inoperable. This has been referred to as the Year 2010 problem .
In the 1972 case Gottschalk v. Benson , the U.S. Supreme Court overturned a lower court 's decision that had allowed a patent for converting BCD-encoded numbers to binary on a computer.
The decision noted that a patent "would wholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itself". [ 60 ] This was a landmark judgement that determined the patentability of software and algorithms . | https://en.wikipedia.org/wiki/Jump-at-8_code |
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