Evidence for unusual spatial location coding in Williams syndrome: An explanation for the local bias in visuo-spatial construction tasks?

Individuals with Williams syndrome (WS) display poor visuo-spatial cognition relative to verbal abilities. Furthermore, whilst perceptual abilities are delayed, visuo-spatial construction abilities are comparatively even weaker, and are characterised by a local bias. We investigated whether this differentiation in visuo-spatial abilities can be explained by a deficit in coding spatial location in WS. This can be measured by assessing participants? understanding of the spatial relations between objects within a visual scene. Coordinate and categorical spatial relations were investigated independently in four participant groups: 21 individuals with WS; 21 typically developing (TD) children matched for non-verbal ability; 20 typically developing controls of a lower non-verbal ability; and 21 adults. A third task measured understanding of visual colour relations. Results indicated first, that the comprehension of categorical and co-ordinate spatial relations is equally poor in WS. Second, that the comprehension of visual relations is also at an equivalent level to spatial relational understanding in this population. These results can explain the difference in performance on visuo-spatial perception and construction tasks in WS. In addition, both the WS and control groups displayed response biases in the spatial tasks. However, the direction of bias differed across the groups. This finding is explored in relation to current theories of spatial location coding

Orientatie-discriminatie en de visuele cortex : een experimenteel onderzoek bij het konijn

Het zenuwstelsel van mens en dier wordt met verschillende methoden bestudeerd. Di t leidt er vaak toe dat de onderzoeksresultaten met die methoden verkregen, resulteren in het ontstaan van onderling gescheiden subdisciplines. Dit geschiedt ook daar waar in beginsel integratie van vakgebieden technisch wel degelijk mogelijk is. Bij het bestuderen van het visueel systeem vormen de resultaten van electrofysiologisch onderzoek met behulp van micro-electroden een vakgebied op zichzelf. Slechts bij uitzondering wordt getracht verbanden te leggen met resultaten van gedragsexperimenten. In dit proefschrift wordt een poging gedaan om te onderzoeken in hoeverre er verband gelegd kan worden tussen visuele discriminatie experimenten bij het konijn en resultaten van electrofysiologisch onderzoek zoals beschreven in de literatuur. De gedachtengang is eenvoudig. Het konijn is in staat lijnstukken van verschillende helling te onderscheiden. Dit is aangetoond door middel van visuele discriminatie experimenten. Verder is uit dergelijke experimenten gebleken dat na ablatie van de visuele cortex het vermogen om lijnstukken van verschillende orientatie te detecteren - in tegenstelling tot het vermogen om vlakken van verschillende helderheid te discrimineren - verloren is

Der Paderborner Stiftsadel zur Mitte des 15. Jahrhunderts : Untersuchungen zum Auf- und Ausbau niederadliger Machtstrukturen

Lagers M. Der Paderborner Stiftsadel zur Mitte des 15. Jahrhunderts : Untersuchungen zum Auf- und Ausbau niederadliger Machtstrukturen. Studien und Quellen zur Westfälischen Geschichte. Vol 74. Paderborn: Bonifatius; 2013

Analysis of reservoir fluids: A review on Constant Volume Depletion

The importance of gas condensates as a hydrocarbon resource is of increasing importance in the world. The phase behaviour of the reservoir fluid should be well known for an appropriate development strategy of the gas condensate field. The complexity of the phase behaviour due to retrograde behaviour makes it necessary to produce good and reliable experimental data, so phase behaviour predictions can be made. These experimental data mostly are produced with constant volume depletion. While the data were analysed numerically, erroneous and non-physical component aspects, such as negative masses and negative densities, appeared. The Constant Volume Depletion experiment is evaluated, the material balance is given with which compositions, densities and masses are calculated and strategies are given for revealing inconect experimental data and for numerical adjustment of that data. Determining the retrograde liquid volume during the experiment seems to be a major source of error. Modifications of the experiment are mentioned and are used to collect extra experimental data, i.e. retrograde liquid compositions and densities during the depletion steps. With these experimental data a check can be made on the material balance calculations. For better results of the Constant Volume Depletion technique it is recommended that a better estimation of the retrograde liquid volume is made.Applied SciencesChemical Technology and Materials ScienceApplied Thermodynamics and Phase Equilibri