Acquisition of new concepts by two amnesic patients

Two Korsakoff amnesics (A.G. and G.S.) and two control subjects were taught six new concepts. Each concept was composed of three parts: the name of the concept, the context in which the concept originated and its definition. The learning procedure consisted of two phases: (1) learning the concept names and definitions by means of the vanishing-cues method; (2) practice on examples of the concepts through a classification task: examples were either set in the same context as that given in the original definition or in mixed contexts (same and new contexts). Subjects were then tested after 24 hours, a week and a month on their ability to identify new examples as belonging to one of the conceptual rules studied (transfer tests). Both patients showed substantial learning. Patient A.G. was slow and dependent of the first letter cues in the vanishing-cues learning phase but nevertheless, she acquired a large and flexible conceptual knowledge and this was especially true for concepts that were practised by means of mixed-context examples. Patient G.S. easily learned to associate the definitions with the concept names but her conceptual knowledge remained more limited. These results confirm the existence of a semantic learning ability in amnesic patients. They also suggest that under appropriate learning conditions, amnesics may eventually acquire a new flexible conceptual knowledge.     

Diffusion coefficients and half-lives of nitric oxide and N-nitroso-L-arginine in rat cortex

In vivo voltammetry was performed in rat brain cortex and in rat brain endothelial constitutive NO-synthase preparations. The use of a recent microcaptor detecting N-hydroxy- and N-nitroso-L-arginine permitted to find only the latest in biological preparations. The construction of a new membrane selective electrode for nitric oxide (NO) allowed to assert its absence in these preparations at micromolar level. Half-live of N-nitroso-L-arginine was 4 s in rat brain cortex and the washout curve of NO after over brain insufflation gave an half-life of 10.5 min; their diffusion coefficients in brain were 3.810(-5) for NO and 3.910(-6) cm2.s-1 for N-nitroso-L-arginine. These facts indicate that N-nitroso-L-arginine is degraded directly into nitrites and citrulline after its synthesis by endothelial NO-synthase.     

Quantitative autoradiography using a radioimager based on a multiwire proportional chamber

Determination of the biodistribution of radiopharmaceuticals is an important issue for the evaluation of their performance in diagnosis and therapy. In this study, we evaluated a digital radioimager (RI) based on a multiwire proportional chamber for quantitative autoradiography (AR). The RI allows direct detection of electronic emissions of gamma emitters. Its qualitative and quantitative performances were tested on 99mTc and (111)In labelled sections and compared with conventional film AR. Linearity of count rate versus activity was verified over a 104 range of activity. As compared with film AR, a substantial improvement of the detection limit was obtained even for acquisition periods up to 20 times less than film exposure times. We provided the basis for quantitative analysis with tissue equivalent paste standards: the 99mTc and (111)In RI counting efficiencies were respectively 1.19% and 2.35%. We illustrated the respective values of RI and film AR in two rat studies: 99mTc-DMSA in kidney and dual-isotope 99mTc-MIBI and (111)In-antimyosin in heart. Calculated activity concentrations on sections of rat organs confirmed good correlation to gamma counting (deviation less than 12%). We suggest RI as a convenient technique for fast localization of single or dual-isotope tracers and determination of activity distribution.     

Housing indicators in europe,a tool for housing research and housing policy?

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Housing indicators in europe, a tool for housing research and housing policy?     

Trouble in paraside? On increasing housing problems in flanders

The survey data for this article was collected by the Center for Social Policy (Antwerp University). At regular intervals, they question a representative number of Belgian families in order to make the operation and effects of social policy measurable. On the basis of that data, this article traces the evolution of housing indicators in Flanders, the Dutch-speaking part of Belgium. After outlining the key issues in housing policy in Belgium and Flanders, the article presents the facts: for several population groups, it sketches the developments of tenure, housing amenities, housing costs, and affordability. The emerging picture is one of overall improvement. Nevertheless, some groups lag behind, while new social groups in need of housing emerge (e.g., lone parents). Age and the number of incomes per family seem to be the breaking points. The second part deals specifically with the housing situation of young families (head under 40 years of age). This population group is (historically) responsible for most new building of houses in Belgium and Flanders. Since we observe a decline in ownership, the reasons for this decline are of strategic importance to our understanding of the level of new housing construction and scarcity on the housing market. At the time of the research,Pascal De Decker (sociologist and urban planner) held an appointment at the Center for Housing and Housing Policy (Steunpunt voor Wonen en Woonbeleid) at Antwerp University (UFSIA). At present, he is an expert consultant to the Cabinet of the Flemish Minister for Urban Policy and Housing. Bert Meulemans (sociologist) supervised the reported research on target groups. He is a researcher at the Center for Social Policy (Centrum voor Sociaal Beleid) at Antwerp University (UFSIA) Veerle Geurts (criminologist) is a researcher at the Center for Housing and Housing Policy (Steunpunt voor Wonen en Woonbeleid) at Antwerp University (UFSIA)     

Efficient Optimal Overlap Removal: Algorithms and Experiments

Motivated by visualizing spatial data using proportional symbols, we study the following problem: given a set of overlapping squares of varying sizes, minimally displace the squares as to remove the overlap while maintaining the orthogonal order on their centers. Though this problem is NP‐hard, we show that rotating the squares by 45 degrees into diamonds allows for a linear or convex quadratic program. It is thus efficiently solvable even for relatively large instances. This positive result and the flexibility offered by constraint programming allow us to study various trade‐offs for overlap removal. Specifically, we model and evaluate through computational experiments the relations between displacement, scale and order constraints for static data, and between displacement and temporal coherence for time‐varying data. Finally, we also explore the generalization of our methodology to other shapes.     

Associative chunk strength in artificial grammar learning.

In 4 experiments, adherence to grammatical rules and associative chunk strength (including different measures, each calculated on the basis of the frequency with which bigrams and trigrams present in the test strings appeared in the learning strings) were manipulated independently in the test phase of an artificial grammar learning task. When participants learned few items of the grammar (Experiments 1A and 2A), the associated items were more often classified as grammatical than the nonassociated ones. On the other hand, when the learning phase included most of the grammatical items (Experiments 1B and 2B), the only effect observed was an effect of grammaticality. These results suggest that, depending on the specific constraints of the tasks, knowledge based on bigrams and trigrams and knowledge based on the abstraction of the grammatical structure can be used for the classification task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential Effects of Furin Deficiency on Insulin Receptor Processing and Glucose Control in Liver and Pancreatic β Cells of Mice

The insulin receptor (IR) is critically involved in maintaining glucose homeostasis. It undergoes proteolytic cleavage by proprotein convertases, which is an essential step for its activation. The importance of the insulin receptor in liver is well established, but its role in pancreatic β cells is still controversial. In this study, we investigated the cleavage of the IR by the proprotein convertase FURIN in β cells and hepatocytes, and the contribution of the IR in pancreatic β cells and liver to glucose homeostasis. β-cell-specific Furin knockout (βFurKO) mice were glucose intolerant, but liver-specific Furin knockout (LFurKO) mice were normoglycemic. Processing of the IR was blocked in βFurKO cells, but unaffected in LFurKO mice. Most strikingly, glucose homeostasis in β-cell-specific IR knockout (βIRKO) mice was normal in younger mice (up to 20 weeks), and only mildly affected in older mice (24 weeks). In conclusion, FURIN cleaves the IR non-redundantly in β cells, but redundantly in liver. Furthermore, we demonstrated that the IR in β cells plays a limited role in glucose homeostasis.