6,848 research outputs found
Chalcogen and Hydrogen Bonds at the Periphery of Arylhydrazone Metal Complexes
No full textLigands comprising an intramolecular resonance-assisted hydrogen bond (RAHB) and an intramolecular resonance-assisted chalcogen bond (RAChB) have been used to form Cu(II), Ag(I), and Cd(II) metal complexes. Both interactions undergo major changes on ligand binding to the metal even though metal-ligand binding does not directly involve either interactions. In fact, the RAChB synthon can act as an intermolecular H-bond donor or acceptor, is involved in intramolecular coordination-coupled proton transfer, or exhibits an ionic pattern
Generation of high-quality charged particle beams during the acceleration of ions by high-power laser radiation
No full textNumerous applications of protons and ions accelerated by laser radiation require charged particle beams of high quality (i.e., such that the ratio of the energy width of the beam to its mean energy is small). In order to produce beams with controlled quality, it is proposed to use two-layer targets in which the first layer consists of heavy multicharged. ions and the second layer (thin and narrow in the transverse direction) consists of protons. The possibility of generating a high-quality proton beam in the interaction of ultraintense laser radiation with such a two-layer target is demonstrated by two- and three-dimensional particle-in-cell computer simulations. (C) 2002 MAIK "Nauka/Interperiodica"
Fluorpyromorphite, Pb5(PO4)3F, a new apatite-group mineral from Sukhovyaz Mountain, Southern Urals, and Tolbachik volcano, Kamchatka
No full textFluorpyromorphite, ideally Pb5(PO4)3F, a new apatite-group member, an F-dominant analog of pyromorphite and hydrox-ylpyromorphite. It is a supergene mineral found at two localities: Sukhovyaz Mountain, Ufaley District, Southern Urals (holotype) and Mountain 1004, Tolbachik volcano, Kamchatka (co-type), both in Russia. At Sukhovyaz, fluorpyromorphite forms anhedral grains up to 0.2 mm across (usually much smaller), filling cavities in quartz and sometimes partially replacing fluorapatite. Associated supergene minerals include pyromorphite, hydroxylpyromorphite, fluorphosphohedy-phane, mimetite, and nickeltsumcorite. At Tolbachik, fluorpyromorphite occurs in the oxidation zone of paleo-fumarolic deposits in close association with pyromorphite, fluorphosphohedyphane, wulfenite, cerussite, munakataite, vanadinite, chrysocolla, and opal. It forms crude long-prismatic to acicular crystals up to 0.1 mm long and up to 5 mu m thick com-bined in bunches and spherulites up to 0.2 mm. Fluorpyromorphite is colorless (Sukhovyaz) or yellow (Tolbachik), translucent to transparent and has a vitreous luster. It is brittle, with an uneven fracture and poor cleavage on (001). The calculated density values are 7.382 (holotype) and 6.831 (cotype) g/cm3. Fluorpyromorphite is optically uniaxial (-). In reflected light, it is light-grey, weakly anisotropic. The reflectance values (Rmin/Rmax, %) are: 15.8/16.6 (470 nm), 16.2/17.2 (546 nm), 15.9/16.9 (589 nm), 15.4/16.2 (650 nm). The chemical composition is (electron microprobe, wt. %; holotype/co-type): CaO 0.10/3.16, SrO 0.17/0.00, PbO 83.51/77.39, P2O516.13/16.35, CrO3 0.00/0.49, SeO3 0.00/0.98, F 1.00/1.35, Cl 0.29/0.40, H2Ocalc 0.13/0.00, -O=(F,Cl) -0.49/-0.66, total 100.84/99.46. The empirical formulae based on 13 anions (O +F + Cl+OH)pfu are Pb4.95Ca0.02Sr0.02P3.00O12F0.70(OH)0.19Cl0.11 (holotype) and Pb4.26Ca0.69P2.83Se6+0.09Cr6+0.06 O11.99F0.87Cl0.14 (co-type). Fluorpyromorphite is hexagonal, space group P63/m, unit-cell parameters (from powder X-ray diffraction data; holotype / co-type) are: a = 9.779(5) / 9.732(1), c = 7.241(9) / 7.242(1) angstrom, V = 599.6(7) / 594.0(2) angstrom 3, and Z = 2. The crystal structure was refined using the Rietveld method to Rp= 0.1764 (holotype). Fluorpyromorphite is isostructural with other members of the apatite group, a subdivision of the apatite supergroup
Computational investigation of the role of low-density lipoprotein and oxygen transport in atherosclerotic arteries
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Competing conventions: The Big Branders’ struggle to incorporate new quality conceptions in the Norwegian food market
No full textThe paper addresses recent changes in the Norwegian agrifood industry from the analytical perspective of quality conventions. Storper and Salais’ “worlds of production” plus Boltanski and Thévenots’ “orders of worth” are used as a basis for the empirical study. First, the paper discusses how the largest Norwegian branders try to strategically adapt to “novel” quality attributes like health-enhancing food, origin/terroir, environmental sustainability and ethics. Second, the paper investigates the companies’ quality signalling strategy: How are these “novel” qualities communicated to consumers? Multiple options are available: Do they attempt to systematically incorporate “novel qualities” into their private brand equity (“conventionalizing qualities”)? Do they prefer a co-labelling scheme with a third party control, or do they use any other measures for quality signalling? The paper thereby discusses how the largest Norwegian branders in the food sector cope with conflicting and competing quality conventions.Food quality, economics of convention., Food Consumption/Nutrition/Food Safety,
On mean value properties involving a logarithm-type weight
No full textsummary:Two new assertions characterizing analytically disks in the Euclidean plane are proved. Weighted mean value property of positive solutions to the Helmholtz and modified Helmholtz equations are used for this purpose; the weight has a logarithmic singularity. The obtained results are compared with those without weight that were found earlier
The Worldview and the Author´s (Self)Reflection in Czech Contemporary Historiography
No full textCílem studie je představit možnosti, jak na základě publikovaných autorských textů zkoumat světový názor historiků a historiček, zejména v oboru soudobých dějin, kde lze předpokládat vliv jejich hodnotového horizontu na interpretaci relativně nedávné minulosti. Autor nejprve vymezuje pojetí světového názoru vzhledem ke stanovenému záměru a zdůvodňuje analytické užití tohoto pojmu v historiografickém textu, v daném kontextu se také zamýšlí nad vztahem paměti, dějin a historiografie. Konstatuje, že poměrně málo českých historiků a historiček dosud reflektuje vztah (individuální či kolektivní) paměti a práce dějepisce, zvláště s ohledem na jeho pozici v současné společnosti, která bývá často redukována na roli objektivního „objevitele historické pravdy“. Taková (sebe)reflexe předpokládá přiznání vlivu individuálního světového názoru historika (komplexu názorů a postojů formovaných výchovou, vzděláním, vzpomínkami, generační příslušností a podobně) na jeho vědeckou činnost. Autor studie nabízí dvě možné a vzájemně se doplňující cesty k poznání historikova světového názoru: jednak prostřednictvím vlastních svědectví a prohlášení z jeho osobněji laděných textů a egodokumentů (eseje, rozhovory, vzpomínky, příspěvky na sociálních sítích), jednak analýzou jeho vědeckých textů (časopiseckých studií, knižních monografií, recenzí). Oba přístupy autor dokumentuje na konkrétních příkladech z produkce historiků a historiček českých soudobých dějin. V závěru studie pak nastiňuje cíle a smysl zkoumání historikova světového názoru.The aim of this study is to present the opportunities for research into the worldview of historians, especially historians focused on contemporary history, where it can be assumed that their set of values may influence their interpretation of the rela-tively recent past. The author first defines the notion of worldview and justifies the analytical use of this concept in historiographical texts. He also considers the relationship between memory, history and historiography in the given context. The author states that not many Czech historians have so far reflected on the relationship between (individual and collective) memory and the work of the historian, especially with regard to his or her position in contemporary society, which is often reduced to the role of an objective “discoverer of historical truth”. Such (self)reflection presupposes the acknowledgement of the influence of the historian’s individual worldview (a complex of opinions and attitudes shaped by upbringing, education, memories, generational affiliation and so on) on his or her scholarly activity. The author of the study offers two possible and complementary ways to learn about the historian’s worldview: first, through his or her own testimonies and statements from more personal texts and ego-documents (essays, interviews, memoirs or social me-dia posts), and second, through the analysis of his or her scholarly texts (journal studies, monographs and book reviews). The author demonstrates both approaches with concrete examples of works by historians of Czech contemporary history and concludes by outlining the aims and purpose of examining the historian’s worldview. © 2022, Institute of Contemporary History of the Czech Academy of Sciences. All rights reserved
Inventering av biologiskt kulturarv
No full textFältmanual till biologiskt kulturarv Föreliggande skrift är framför allt en fältmanual till biologiskt kulturarv (och ett urval av andra biologiska kulturbärare), en checklista med bilder och beskrivningar. Det tar också upp några aspekter på själva metodiken för inventering, kartering och tolkning. Fältmanualen omfattar de vanligaste aspekterna av biologiskt kulturarv som man kan hitta i svenska landskap från söder till norr. Listan beskriver biologiskt kulturarv huvudsakligen från nivåerna egenskaper, individer och artförekomster enligt RAÄ:s indelning
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