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排序方式: 共有112条查询结果,搜索用时 15 毫秒
1.
This paper studies the modelling of legal reasoning about evidence within general theories of defeasible reasoning and argumentation. In particular, Wigmore's method for charting evidence and its use by modern legal evidence scholars is studied in order to give a formal underpinning in terms of logics for defeasible argumentation. Two notions turn out to be crucial, viz. argumentation schemes and empirical generalisations.  相似文献   
2.
The amount of information available to information workers recently has becomeoverwhelming. This confronts information workers with two majorproblems: finding the information needed, and accessing it; they arecalled the search problem and the access problem, respectively. Asthe main result of our research an architecture is specified of anautomated tool that provides integrated support for searching andaccessing multimedia documents that may be located at arbitraryplaces. The architecture contains a database with information aboutthe documents and with thesaurus-like information. The architecturealso contains a browse mechanism and a query mechanism for inspectingthe database. In the design process of the architecture, severalfundamental questions arose, like “What is a document?”and “ What is a medium kind?”. The developed answers tosome of these questions are considered to have a general characterand thus to be useful also outside the scope of the research at hand.The paper concludes with an overview of the current status of theproject and a discussion of future work.  相似文献   
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Although the number of therapeutic options for the treatment of inflammatory bowel disease (IBD) has increased in recent years, patients suffer from decreased quality of life due to non-response or loss of response to the currently available treatments. An increased understanding of the disease’s etiology could provide novel insights for treatment strategies in IBD. Lymphatic system components are generally linked to immune responses and presumably related to inflammatory diseases pathophysiology. This review aims to summarize findings on immune-mediated mechanisms in lymphoid tissues linked with IBD pathogenesis and (potential) novel treatments. Enhanced innate and adaptive immune responses were observed in mesenteric lymph nodes (MLNs) and other lymphoid structures, such as Peyer’s patches, in patients with IBD and in animal models. Furthermore, the phenomenon of lymphatic obstruction in the form of granulomas in MLNs and lymphatic vessels correlates with disease activity. There is also evidence that abnormalities in the lymphatic stromal components and lymph node microbiome are common in IBD and could be exploited therapeutically. Finally, novel agents targeting lymphocyte trafficking have been added to the treatment armamentarium in the field of IBD. Overall, gut-associated lymphoid tissue plays a key role in IBD immunopathogenesis, which could offer novel therapeutic targets.  相似文献   
5.
Asymmetric hydrogenation of methyl acetoacetate to methyl (R)-3-hydroxybutyrate by [(R)- RuCl(binap)(p-cymen)]Cl has been studied in methanol-ionic liquid and methanol- dense CO2 solvent systems. The ionic pairs triethylhexylammonium and 1-methylimidazolium with bis(trifluoromethane sulfonyl) imide and hexafluorophosphates were used. The role of ionic pairs on the kinetic parameters and (enantio)selectivity has been demonstrated. Although the CO2 expanded methanol system suffered from a reduction in both reaction rate and product selectivity, this changed in the presence of water. The high selectivity of the optimized methanol-CO2-water-halide system was designed as a consequence of observed additive effects.  相似文献   
6.
The “Noyori” Ru-BINAP chiral complex is an industrially used homogeneous catalyst for stereoselective hydrogenations providing valuable fine chemicals with high optical yields. Its pseudo-immobilisation with help of various ionic liquids (ILs) represents an alternative to the not very efficient heterogenisation on inorganic supports. Many ILs are commercially readily available or could simply be produced, but in both cases a problem of their purity is encountered. Presence of even trace impurities may either suppress or promote the reaction progress, and most importantly, the parameter of enantioselectivity. The complex treatment of the reaction system must be always accepted whenever a genuine role of an ionic liquid is discussed. For this purpose a well understood reaction system—asymmetric hydrogenation of methyl-3-oxobutanoate (methylacetoacetate/MAA) to methyl-3-hydroxybutanoate (methylhydroxybutyrate/MHB) over the chiral Noyori type Ru-BINAP catalyst in the ethanol-bmimPF6 reversibly biphasic mixed phase was chosen. Self-prepared bmimPF6 ionic liquid was exposed to a series of normalized purification steps based on a theoretical semi-mechanistic model. It provided a clear evidence of the number and duration of necessary purification steps together with an effective “value” of each of them. Another important data were collected in the form of pseudo-ternary phase diagrams for all major components including the model impurities.  相似文献   
7.
Abstract Practical experience in the development of computer-based geometry exercises and their use in the classroom for a course on the equation of a straight line are presented. The task of creating the exercises with an authoring system for geometry is described first. Some didactical problems raised by this work are analysed in detail. The production time is estimated and discussed. A classroom experiment with pupils aged 15/16 is then presented and the teacher's organization problems are given (i.e. time spent on technical instruction, time-sharing between theory and practice, tackling the lack of material). Some pedagogical issues are then discussed.  相似文献   
8.
The field of organic electronics is advancing quickly towards ultra low-cost, low-end applications and is expected to provide the necessary technology required for flexible/printed electronics. Here we address the need for solution processed low-voltage complementary logic in order to reduce power consumption of organic circuits and hence enable their use in portable, i.e. battery-powered applications. We demonstrate both p- and n-channel solution processed high performance organic field-effect transistors that operate at voltages below |1.5| V. The reduction in operating voltage is achieved by implementing ultra-thin gate dielectrics based on solution processed self-assembled monolayers. This work demonstrates the feasibility of fabricating low-voltage complementary organic circuits by means of solution processing.  相似文献   
9.
Covalently bound azide on a (small) organic molecule or a (large) biomolecular structure has proven an important handle for bioconjugation. Azides are readily introduced, small, and stable, yet undergo smooth ligation with a range of reactive probes under mild conditions. In particular, the potential of azides to undergo metal‐free reactions with strained unsaturated systems has inspired the development of an increasing number of reactive probes, which are comprehensively summarized here. For each individual probe, the synthetic preparation is described, together with reaction kinetics and the full range of applications, from materials science to glycoprofiling. Finally, a qualitative and quantitative comparison of azido‐reactive probes is provided.  相似文献   
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