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51.
The domain analysis process is used to identify and document common and variable characteristics of systems in a specific domain. In order to achieve an effective result, it is necessary to collect, organize and analyze several sources of information about different applications in this domain. Consequently, this process involves distinct phases and activities and also needs to identify which artifacts, arising from these activities, have to be traceable and consistent. In this context, performing a domain analysis process without tool support increases the risks of failure, but the used tool should support the complete process and not just a part of it. This article presents a systematic review of domain analysis tools that aims at finding out how the available tools offer support to the process. As a result, the review identified that these tools are usually focused on supporting only one process and there are still gaps in the complete process support. Furthermore, the results can provide insights for new research in the domain engineering area for investigating and defining new tools, and the study also aids in the identification of companies’ needs for a domain analysis tool.  相似文献   
52.
The solubility of calcium carbonate (limestone) particles depends on the amount of CO2 dissolved in the water, which is a function of temperature and the pressure of CO2 that is in equilibrium with water. At a constant temperature, increasing CO2 pressure increases the solubility of CaCO3, and decreasing CO2 pressure favours the crystallisation of CaCO3. This dissolution–crystallisation behaviour of CaCO3 can be used in the development of carbonate binders—a process called “cold sintering”—of limestone. This paper examines the effect of a range of parameters on the cold sintering process of limestone powder. The parameters studied are CO2 gas pressure (atmospheric, 10 atm and 35 atm), exposure time (0–90 min), post-compaction pressure (10 and 15 MPa) and compact pressing time (10–60 min). The water/limestone powder ratio was kept constant at 0.2 (by weight). The compressive strength of the limestone compacts was used as a measure of the efficiency of the carbonate binder formation process, and scanning electron microscopy was used to study the microstructural developments. The results show that carbonate binders can be produced by cold sintering of limestone powder. Exposure of limestone compacts to high CO2 pressure followed by post-compaction at high mechanical pressure, enhances the strength of the compact. From the microstructural data, it is evident that newly formed calcium carbonate crystal growths are responsible for the strength improvements observed. The amount of water that is used in the limestone powder mixture is one factor that controls the quantity of the cementing phase. Future work has to be focussed on the application of methods to further increase the solubility of calcium carbonate, as the amount of calcium carbonate available for recrystallisation is important in producing a strong binder.  相似文献   
53.

Several challenges need to be met by a new generation of learning services. On one hand, they need to fit into a ubiquitous and serendipitous learning vision, to adapt to different types of users with different backgrounds and needs. On the other hand, they need to integrate modern pedagogical approaches of learning. These services will probably rely on the cooperation of different distributed, autonomous, goal-oriented entities, and they can be Grid- or Web-Oriented. In this paper, we show how core technologies can contribute to the development of a next generation of learning services. In particular, we focus our attention on personalized services delivery for learning by employing an ontological perspective and user modeling techniques. This paper presents some preliminary results obtained within Elegi FP6 project.  相似文献   
54.
Object perception requires interpolation processes that connect visible regions despite spatial gaps. Some research has suggested that interpolation may be a 3-D process, but objective performance data and evidence about the conditions leading to interpolation are needed. The authors developed an objective performance paradigm for testing 3-D interpolation and tested a new theory of 3-D contour interpolation, termed 3-D relatability. The theory indicates for a given edge which orientations and positions of other edges in space may be connected to it by interpolation. Results of 5 experiments showed that processing of orientation relations in 3-D relatable displays was superior to processing in 3-D nonrelatable displays and that these effects depended on object formation. 3-D interpolation and 3-D relatabilty are discussed in terms of their implications for computational and neural models of object perception, which have typically been based on 2-D-orientation-sensitive units. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
55.
Induction of BDNF-TrkB signaling is associated with the action mechanisms of conventional and fast-acting antidepressants. GSB-106, developed as a small dimeric dipeptide mimetic of BDNF, was previously shown to produce antidepressant-like effects in the mouse Porsolt test, tail suspension test, Nomura water wheel test, in the chronic social defeat stress model and in the inflammation-induced model of depression. In the present study, we evaluated the effect of chronic per os administration of GSB-106 to Balb/c mice under unpredictable chronic mild stress (UCMS). It was observed for the first time that long term GSB-106 treatment (1 mg/kg, 26 days) during ongoing UCMS procedure ameliorated the depressive-like behaviors in mice as indicated by the Porsolt test. In addition, chronic per os administration of GSB-106 resulted in an increase in BDNF levels, which were found to be decreased in the prefrontal cortex and hippocampus of mice after UCMS. Furthermore, prolonged GSB-106 treatment was accompanied by an increase in the content of pTrkB706/707 in the prefrontal cortex and by a pronounced increase in the level of pTrkB816 in both studied brain structures of mice subjected to UCMS procedure. In summary, the present data show that chronic GSB-106 treatment produces an antidepressant-like effect in the unpredictable chronic mild stress model, which is likely to be associated with the regulation of the BDNF-TrkB signaling.  相似文献   
56.
In this study, chemical transformations of benzyl ester of О-(phenyl-2-acetamido-2,3-dideoxy-1-thio-β-d-glucopyranoside-3-yl)-d-lactoyl-l-alanyl-d-isoglutamine (SPhMDPOBn) on the fumed silica surface were examined, and the surface complex structure was characterized by temperature-programmed desorption mass spectrometry (TPD-MS), infrared spectroscopy (FTIR) and electrospray ion trap mass spectrometry (ES IT MS). Stages of pyrolysis of SPhMDPOBn in pristine state and on the silica surface have been determined. Probably, hydrogen-bonded complex forms between silanol surface groups and the C = O group of the acetamide moiety NH-(CH3)-C = O…H-O-Si≡. The thermal transformations of such hydrogen-bonded complex result in pyrolysis of SPhMDPOBn immobilized on the silica surface under TPD-MS conditions. The shifts ∆ν of amide I band (measured from 1,626 to 1,639 cm−l for SPhMDPOBn in pristine state) of 33 and 35 cm−l which occurred when SPhMDPOBn was immobilized on the silica surface may be caused by a weakening of the intramolecular hydrogen bonding of the SPhMDPOBn because the interaction with the silica surface as hydrogen bond with silanol groups is weaker than that in associates.  相似文献   
57.
The ability of NQO2 to increase the production of free radicals under enhanced generation of quinone derivatives of catecholamines is considered to be a component of neurodegenerative disease pathogenesis. The present study aimed to investigate the neuroprotective mechanisms of original NQO2 inhibitor M-11 (2-[2-(3-oxomorpholin-4-il)-ethylthio]-5-ethoxybenzimidazole hydrochloride) in a cellular damage model using NQO2 endogenous substrate adrenochrome (125 µM) and co-substrate BNAH (100 µM). The effects of M-11 (10–100 µM) on the reactive oxygen species (ROS) generation, apoptosis and lesion of nuclear DNA were evaluated using flow cytometry and single-cell gel electrophoresis assay (comet assay). Results were compared with S29434, the reference inhibitor of NQO2. It was found that treatment of HT-22 cells with M-11 results in a decline of ROS production triggered by incubation of cells with NQO2 substrate and co-substrate. Pre-incubation of HT-22 cells with compounds M-11 or S29434 results in a decrease of DNA damage and late apoptotic cell percentage reduction. The obtained results provide a rationale for further development of the M-11 compound as a potential neuroprotective agent.  相似文献   
58.
59.
To elucidate the dynamic interactions of cortical and subcortical oculomotor systems, the authors investigated reflexive and strategic control over fixation and saccades in patients with chronic unilateral lesions that involved either frontal or parietal cortex. They measured the effects of indicating the location of the forthcoming target and removing the fixation stimulus on the latencies of eye movements toward a peripheral visual target in 12 patients with frontal eye field (FEF) lesions, 9 patients with lesions restricted to parietal cortex, and 12 neurologically healthy controls. They found that chronic damage to FEF cortex disrupts cortico-collicular interactions, resulting in hypoactivity in the contralesional superior colliculus and a loss of strategic control over the intrinsic collicular circuits that regulate fixation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
60.
Physical–mechanical properties of superconducting polymer–ceramic composites, obtained on the basis of oxide ceramics Y1Ba2Cu3O7−x and a number of polymeric binders have been investigated. As it could be expected, the decrease of temperature of composite experiments till cryogen temperature leads to a rigid decrease of deformation of materials. However, it increases their resistance to rupture.

The influence of granule metrical content and degree of filling Y1Ba2Cu3O7−x by ceramic on the interstitial boundary, the module of flexibility, elongation, and on the critical temperature of transition into superconducting condition has been investigated. It has been discovered, that regardless of the size of ceramic's grains, the increase of its amount leads to the increase of resistance to rupture, module and to the decrease of limiting deformation, whereas the increase of average sizes of ceramic's grains worsens resistant properties. However, it increases superconducting properties of composites.

Thermo-physical properties for superconducting polymer–ceramic composites with superhighmolecular polyethylene and isotactic polypropylene binders has been investigated. For the composites mentioned the increase of melting heats has been found out. This has been explained by intercalation of macromolecules’ fragments into the interstitial layer of ceramics’ grains. This phenomena leads to the change of morphological structure of superconducting nano-composites obtained. The latter has been proved by electron microscopy.  相似文献   

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