1,427 research outputs found
Do estimable relations exist between size and efficiency of institutions and productivity growth? An exercise in the spirit of D. C. North
No full textThis paper, seeks to test the Fuess and van den Berg (1992) hypothesis on the influence of transactions costs on the productivity growth rate for the Italian economy in the period 1951-89, taking into account the increasing size of the transactions sector.
Some sulphur-nitrogen ring transformations using tetrasulphur tetranitride and trichlorotrithiatriazene as precursors
No full textAs part of a general study of 1, 2, 3, 5-dithiadiazolium cations, a series of 4-phenyl-1, 2, 3, 5-dithiadiazolium salts were produced by anion exchange reactions, both in the solid phase and in solution. The reduction of the 4-phenyl -1, 2, 3, 5- dithiadiazoliurn cation gave the previously unreported, 4-phenyl- 1, 2-dithia-3, 5-diazole, the crystal structure of which indicates that the dithiadiazole exists as an eclipsed dimmer. By analogy with the solid phase exchange reactions which occur between 4-phenyl-1, 2, 3, 5-dithiadiazolium chloride and Group I metal halides, the metathetical reactions between s (_3) N (_2) Cl and metal halides were investigated. The product isolated from the reaction of s (_3) N(_2) Cl with CsI was identified as tetrasulphur tetranitride. The reductions of S (_4) N (_3) C1, S (_3) N (_2) C1 (_2) and (NSC1) (_3) were studied using a variety of reducing agents. The majority of the reduction reactions gave tetrasulphur tetranitride but the reduction of trichlorotrithiatriazene by iron using sulphur dioxide as a solvent provided a convenient synthesis of the cyclocyclopentathiapentazenium cation (S (_5) N (_5) +). The reduction of chlorothiodithiazyl chloride by iron using sulphur dioxide as a solvent produced the previously unreported salt (s (_10) N (_8) (^2) +) (FeC1 (_4) -) (_2). The synthesis of the cations S (_x) N (^+) (x>l) was approached from two angles, that of reacting sulphur polycations (s (_8) (^2+) (AsF (_6) (^-)) (_2)) with nitrogen containing species (MN (_3) and S (_4) N (_4) and that of reacting the thionitrosyl cation (NS (^+)) with sulphur. The reactions of s (_8) (^2) (^+) (AsF (_6) (^-)) (_2) with azides and tetrasulphur tetranitride led to the formation of the S (_2) N(^+) cation and with excess tetrasulphur tetranitride to the production of S (_10) N (_8) (^2) (^+) (AsF (_6) (^-)) (_2) Some preliminary investigative reactions of selenium (Se (_4) (^2) (^+) (AsF (_6) (^-)) (_2) and Se (_8) (^2) (^+) (AsF (_6) (^-)) (_2)) and tellurium (Te (_4) (^2) (^+) (AsF (_6) (^-)) (_2)) polycations with both azides and tetrasulphur tetranitride were carried out and a selenium analogue of "S (_3) N (_2) (^+)” isolated. In an attempt to prepare thiazyl fluoride (as a precursor to thionitrosyl salts) by a simple single stage process, chlorine monofluoride was reacted with S (_4) N (_4) and (NSCL) (_3) are discussed. NSF was synthesised by a metathersis reaction between thiazyl chloride and cesium fluoride. A facile route to the thionitrosyl cation via the oxidation of (NSCL) (_3) and S (_4) N (_4) using Group V Lewis acids (AsF (_5), SbF (_5)) at 100-150 C failed. However a convenient route to thionitrosyl hexachloroantimonate (v) has been found in the vapour phase reaction of thiazyl chloride with antimony pentachloride
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Object based data access at the D0 experiment
No full textThe D{O} Experiment at Fermilab is currently participating in the FNAL Computing Division`s ``Computing for Analysis Project`` (CAP) to investigate object based data storage and access. Following a short description of the CAP system architecture, the D{O} data model is explored. A brief discussion of the method of operation of the CAP system leads into a concluding section
Looking underneath fullerenes on Au(110): Formation of dimples in the substrate
No full textThe adsorption of organic molecules on metal surfaces can lead to complex nanostructuration of the supporting substrate. The precise atomistic and electronic structures of the C60/Au(110) interface are unveiled by combining synchrotron-based diffraction and spectroscopic techniques with density functional theory calculations. We show that the interaction between C60 molecules with Au(110) surface induces a massive interface reorganization, which leads to the Au(110)-p(6 x 5) substrate reconstruction and to the formation of surface nanodimples. The fullerenes are hosted by these nanodimples, which are one and two layers deep. We provide evidence that the larger contact area between the C60 and the metal, which results from the substrate rearrangement, allows for the formation of strong directional C-Au bonds
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Electroweak boson pair production in p{bar p} collisions at {radical}s = 1.8 TeV
No full textResults from CDF on W{sup +}W{sup {minus}}, WZ, and W{gamma} production in {radical}s = 1.8 TeV {bar p}-p collisions from the 1992--1993 collider run are presented. Direct limits on WW{gamma} and WWZ anomalous couplings are obtained
Study of intermittency in h h collisions at s**(1/2) = 16.7 GeV.
No full textCharged-particle multiplicity distributions from hadron-hadron collisions at sqrt{s} =16.7 GeV are analyzed in rapidity, pseudorapidity and azimuthal angle intervals. The data—fully reconstructed events—were taken in the rapid-cycling Bubble Chamber of the International Hybrid Spectrometer Consortium exposed to a hadron beam (147 GeV/c momentum) of the Tevatron at Fermilab. The factorial moments of the multiplicity distributions increase with decreasing rapidity interval. The energy dependence of the slopes in h-h collisions is discussed. Suitable phase-space cuts show that most of the intermittency effect stems from low-transverse-momentum particles. In the two-dimensional analysis (rapidity azimuthal angle) we find a weak enhancement of the slope values, more in agreement with the observations by the NA22 experiment, rather than the observations in e+e− by the HRS collaboration
The Saif al-mulūk wa-l-ḥukkām of Muḥyī ad-Dīn Muḥammad b. Sulaimān al-Kāfiyaǧī (d. 1474), Edition, translation and commentary.
No full textMuḥyi ad-Dīn al-Kāfiyaǧī, Verfasser des Werkes Saif 'l-mulūk wa-l-ḥukkām (Das Schwert der Könige und Herrscher), lebte im fünzehnten Jahrhundert im mamlukischen Kairo.
Sein Werk ruft die Herrscher zur Ausübung der Gerechtigkeit und zur Fürsorge gegenüber ihren Völkern auf. Gleichzeitig ruft es die Völker dazu auf, den gerechten Herrschern Gehorsam entgegen zu bringen. Dabei unterstreicht es von Beginn an die Gerechtigkeit als menschlichen und sozialen Wert, zu dem Gott die Menschen aufrief und sie dabei aufforderte, ihn als Hauptbedingung für den Zusammenhalt der islamischen Gesellschaft zu betrachten, um infolgedessen deren Fortbestand und Entwicklung zu garantieren. Saif 'l-mulūk wa-l-ḥukkām behandelt somit wichtige politische, soziale und moralische Themen und stellt Reformen in Form von Ratschlägen und Hinweisen vor.
Das Werk gehört zum Genre des „Fürstenspiegels“. Aus diesem Grund soll diese Arbeit einen Überblick über die Kunst des Fürstenspiegel und seiner Entwicklung im muslimischen Kontext geben und eine Liste von Schriften erstellt werden, die man als Ratgeberliteratur bezeichnen kann. Da es sich bei dieser Arbeit um eine Edition des Werkes handelt, werden zunächst die Inhalte des Manuskripts und der Abschriften erklärt. Es folgt die Edition und die Übersetzung des Textes mit Kommentaren zum Manuskript und dessen wissenschaftlicher Bedeutung. Unter anderem sollen dabei die ursprünglichen Beweggründe für das Verfassen des Werkes geklärt werden.Muḥyi ad-Dīn al-Kāfiyaǧī, author of Saif 'l-mulūk wa-l-ḥukkām (The sword of kings and rulers), lived in Mamluk Cairo in the fifteenth century.
His work reminds rulers to practice justice and benevolence towards their suzerains. At the same time it urges people to show obedience to their just rulers. Central for the work is its emphasis for justice as a human and social value, which was postulated from God, who demanded from the human kind to guarantee the main requirements for the cohesion and maintenance of the Islamic society. Thus Saif 'l-mulūk wa-l-ḥukkām discusses important political, social and moral issues and presents reforms in terms of advice and suggestions.
The book belongs to the genre of ”Mirrors of Princes”. Therefore this study is supposed to give an overview of the genre and its development in a Muslim context. Furthermore it will contain a list of works, which can be seen as advising literature. Since this study is an edition of al-Kāfiyaǧīs work, it will explain the content of the manuscripts first, followed by the edition and translation of the text with commentaries about the manuscript and its scientific significance. Among other things this part will attempt to clarify the original motives for writing Saif 'l-mulūk wa-l-ḥukkām
Contributions of Crystallography to Materials Science
No full textThe properties o fmaterials used in various domains of science and engineering are directly correlated to the microstructure. Crystallography is devoted to the investigaton of microstructure of substances and materials by a variety of diffraction and spectroscopic methods. Several examples related to research in the department of materials science at the Technical University of Darmstadt are presented. The structure and dynamics of aromatic host molecules in catalytically active zeolites are investigated by X-ray and neutron diffraction and NMR-spectroscopy combined with inelastic neutron scattering. Surfaces and interfaces of semiconductors and thin superconducting films are studied by grazing incidence techniques. By examination of the reflectogram details on thickness, composition, surface roughness and a possible modification of these values are obtained. Transmission electron microscopy provides complementary information on the structure of interfaces, especially through the support of simulated images by a multi-slice method. Work is presented on CoSi2-filmson Si and wafers of GaAs with LaB6 films. Modification of the seewafers by ion mixing techniques is attempted. Furthermore, surface hardening of steel by ion implantation (carbon and nitrogen) is away of improving tribological properties. Grazing incidence provides results on the formation of different carbides as a function of depth. Superconducting films of Bi2Sr2CaCu20s on SrTi03 showed an improvement by a factor of 10 in critical current density by creating holes (Xe,Au, U'-irradiation) as pinning centres. The examination by TEM revealed an amorphization of the channel s with dear boundaries between the channel and nonirradiated material
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Inclusive J/{psi}, {psi}(2S) and b-quark production in {bar p}p collisions at {radical}s = 1.8 TeV
No full textInclusive J/{psi} and {psi}(2S) production has been studied in {bar p}p collisions at {radical}s = 1.8 TeV using the Collider Detector at Fermilab. The products of production cross section times branching fraction have been measured as functions of P{sub T} for J/{psi}({psi}(2S)) {yields} {mu}{sup +}{mu}{sup {minus}} in the kinematic range P{sub T}{sup J/{psi}({psi}(2S))} > 6 GeV/c and {vert_bar}{eta}{sup J/{psi}({psi}(2S)){vert_bar}} {le} 0.5. The products of the integrated cross section times branching fraction are calculated and used to obtain an inclusive b-quark production cross section
A Multi-Omics Approach to Investigate Immune Regulation of Host Symbiont Dynamics in Astrangia poculata
No full textAstrangia poculata is a temperate coral model system that engages in a facultative relationship with its algal symbiont meaning that it can exist in states of high symbiont density (brown), and low symbiont density (white) with no apparent cost to its fitness. Astrangia poculata can also be found in mixed forms which have brown and white polyps on a single individual, however the effects of symbiont density on immunity is poorly understood. Fortunately, A. poculata’s facultative nature makes it an ideal model for studying how symbiont density affects immunity. In this project, we split mixed A. poculata colonies into high and low symbiont density portions for the purpose of conducting immune assays, transcriptomics, and symbiont counts. DNA and RNA were extracted then processed and the data was analyzed. The corals were then airbrushed to remove tissue from the skeleton in order to perform immune assays. No significant differences were found in immunity between symbiont state within individual colonies, but protein synthesis and metabolic processes were found to be enriched in the high symbiont density portion, while structural integrity was enriched in the low symbiont density portion. The data gathered from this study has contributed to an understanding of how symbiont density contributes to the coral's immune system and differential gene expression.Biolog
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