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1.
Despite new developments in the concept of vascular dementia, the Hachinski Ischemic Score (HIS) and its modified versions continue to be widely used in the clinical differentiation of Alzheimer's disease (AD) and ischemic vascular dementia (IVD). The sensitivity of the HIS and two modified versions in the diagnosis of AD, IVD, and single infarcts in a large, geriatric population with mild cognitive impairment (N = 100) was evaluated. Sensitivity for identification of AD was greater than 90% but was less than 70% for IVD. Over one third of patients with one or more infarcts on computed tomographic brain scans and 63% of mixed cases were classified as having probable AD. It is concluded that ischemic scores may be useful at predicting prevalence rates if individual case accuracy is ignored. Despite being sensitive to identifying AD, ischemic scores are insensitive to both cerebral infarction and IVD and cannot reliably exclude IVD. Finally, patients with mixed dementia should not be expected to have intermediate scores.  相似文献   
2.
Abstract

We are developing the control architecture of a portraitist artificial agent called DrawBot that reproduces the visuomotor behaviour of a human carrying out a realistic portrait. The visuomotor strategy adopted by DrawBot is based on computational models of eye movements in human beings,and one xperimental findings on eye-hand coordination in expert draughtsmen. In this paper we present a behavioural model of the visuomotor coordination adopted by a draughtsman, designed in terms of visual routines.Eventually we outline the implementation of the basic routines.  相似文献   
3.
Most one-dimensional soil moisture flow simulation models have restricted applicability due to (amongst other things): i) insufficient user flexibility; ii) a lack of user friendliness; iii) dependency on scale, temporal and/or spatial, and iv) fixed boundary conditions. Therefore, we developed a simple and highly flexible software package to simulate, visualize and analyze 1-D moisture flow in soils: SoWaM (Soil Water Model). The package has a modular setup and consists of a range of tools to visualize, analyze and compare input data and results. Soil hydraulic properties for each specified soil layer can be defined by either Van Genuchten parameters or cubical splines. Since the model does not impose limits on element size or time interval, it is possible to perform simulations in very high detail, both spatially and temporally. Furthermore, four different criteria for irrigation scheduling have been implemented. The SoWaM package provides an accurate, simple and highly flexible tool to simulate soil moisture flow and to evaluate the effects of various factors on soil water movement, such as timing and amount of irrigation, soil hydraulic properties and soil layering. Results of a case study are presented to illustrate model performance.  相似文献   
4.
This paper is a report about the use of Matita, an interactive theorem prover under development at the University of Bologna, for the solution of the POPLmark Challenge, part 1a. We provide three different formalizations, including two direct solutions using pure de Bruijn and locally nameless encodings of bound variables, and a formalization using named variables, obtained by means of a sound translation to the locally nameless encoding. According to this experience, we also discuss some of the proof principles used in our solutions, which have led to the development of a generalized inversion tactic for Matita.  相似文献   
5.
The chick chorioallantoic membrane (CAM) assay model of angiogenesis has been highlighted as a relatively quick, low cost and effective model for the study of pro-angiogenic and anti-angiogenic factors. The chick CAM is a highly vascularised extraembryonic membrane which functions for gas exchange, nutrient exchange and waste removal for the growing chick embryo. It is beneficial as it can function as a treatment screening tool, which bridges the gap between cell based in vitro studies and in vivo animal experimentation. In this review, we explore the benefits and drawbacks of the CAM assay to study microcirculation, by the investigation of each distinct stage of the CAM assay procedure, including cultivation techniques, treatment applications and methods of determining an angiogenic response using this assay. We detail the angiogenic effect of treatments, including drugs, metabolites, genes and cells used in conjunction with the CAM assay, while also highlighting the testing of genetically modified cells. We also present a detailed exploration of the advantages and limitations of different CAM analysis techniques, including visual assessment, histological and molecular analysis along with vascular casting methods and live blood flow observations.  相似文献   
6.
In this paper, the tensile, fatigue and creep properties of the Ferritic/Martensitic (F/M) steel T91 and of the Austenitic Stainless (AS) Steel 316L in lead-bismuth eutectic (LBE) or lead, obtained in the different organizations participating to the EUROTRANS-DEMETRA project are reviewed. The results show a remarkable consistency, referring to the variety of metallurgical and surface state conditions studied. Liquid Metal Embrittlement (LME) effects are shown, remarkable on heat-treated hardened T91 and also on corroded T91 after long-term exposure to low oxygen containing Liquid Metal (LM), but hardly visible on passive or oxidized smooth T91 specimens. For T91, the ductility trough was estimated, starting just above the melting point of the embrittler (TM,E = 123.5 °C for LBE, 327 °C for lead) with the ductility recovery found at 425 °C. LME effects are weaker on 316L AS steel. Liquid Metal Assisted Creep (LMAC) effects are reported for the T91/LBE system at 550 °C, and for the T91/lead system at 525 °C. Today, if the study of the LME effects on T91 and 316L in LBE or lead can be considered well documented, in contrast, complementary investigations are necessary in order to quantify the LMAC effects in these systems, and determine rigorously the threshold creep conditions.  相似文献   
7.
8.
Velocity-field curves for surface free-carriers in silicon are determined from measurements on resistivegate IGFETs. The measurements were performed on n-channel devices fabricated on both (100) and (111) substrates and on p-channel devices fabricated on (100) substrates. The channel length of the devices is ~8 μm and the impurity concentration of the substrates is ~ 1015 cm?3. The dependence of velocity on the field strength along the channel is found to be well approximated by an empirical relationship involving three parameters: low-field mobility μ0, a critical field Ecy signalling the onset of velocity saturation, and a parameter α that determines the curvature between the constant-mobility and constant-velocity branches of the curve. The curve-fitting parameters are given in tabular form for the two n-channel and one p-channel systems studied. The dependence of the velocity-field curves on temperatures in the range 100–350K is also reported.  相似文献   
9.
Advances in wireless sensing and actuation technology allow embedding significant amounts of application logic inside wireless sensor networks. Such active WSN applications are more autonomous, but are significantly more complex to implement. Event-based middleware lends itself to implementing these applications. It offers developers fine-grained control over how an individual node interacts with the other nodes of the network. However, this control comes at the cost of event handlers which lack composability and violate software engineering principles such as separation of concerns. In this paper, we present CrimeSPOT as a domain-specific language for programming WSN applications on top of event-driven middleware. Its node-centric features enable programming a node’s interactions through declarative rules rather than event handlers. Its network-centric features support reusing code within and among WSN applications. Unique to CrimeSPOT is its support for associating application-specific semantics with events that carry sensor readings. These preclude transposing existing approaches that address the shortcomings of event-based middleware to the domain of wireless sensor networks. We provide a comprehensive overview of the language and the implementation of its accompanying runtime. The latter comprises several extensions to the Rete forward chaining algorithm. We evaluate the expressiveness of the language and the overhead of its runtime using small, but representative active WSN applications.  相似文献   
10.
Abstract This paper reports on an experiment in which a whole semester course in psychology was replaced by a mixed formula consisting of a CD-ROM complemented by a series of seminars and workshops. The CD-ROM was conceived as a collection of documents (hypertexts, research data, references, videos and activities) linked together with genuine Netscape facilities. Students were invited to search through these documents for information to answer questions (called challenges ) on the topic. A multiple-choice questionnaire accompanied each challenge in order to foster students' self-evaluation. The seminars, held every other week, served both as forums to discuss each of the topics under the guidance of an expert. Careful analysis of students' answers to two questionnaires at the beginning and end of the course and during interviews, showed that such a formula was favourably accepted by a large majority of students, although it lead to more anxiety and work load than a traditional course. Positive effects were also observed on learning.  相似文献   
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