38 resultados para allelic discrimination
Resumo:
Heritage tourism depends on a physical resource based primarily on listed buildings and scheduled monuments. Visiting or staying in a historic building provides a rich tourism experience, but historic environments date from eras when access for disabled people was not a consideration. Current UK Government policy now promotes social inclusion via an array of equal opportunities, widening participation and anti-discrimination policies. Historic environments enjoy considerable legislative protection from adverse change, but now need to balance conservation with public access for all. This paper discusses the basis of research being undertaken by The College of Estate Management funded by the Mercers Company of London and the Harold Samuel Trust. It assesses how the 1995 Disability Discrimination Act has changed the legal obligations of owners/operators in managing access to listed buildings in tourism use. It also examines the key stakeholders and power structures in the management of historic buildings and distinguishes other important players in the management process.
Resumo:
Infants' responses in speech sound discrimination tasks can be nonmonotonic over time. Stager and Werker (1997) reported such data in a bimodal habituation task. In this task, 8-month-old infants were capable of discriminations that involved minimal contrast pairs, whereas 14-month-old infants were not. It was argued that the older infants' attenuated performance was linked to their processing of the stimuli for meaning. The authors suggested that these data are diagnostic of a qualitative shift in infant cognition. We describe an associative connectionist model showing a similar decrement in discrimination without any qualitative shift in processing. The model suggests that responses to phonemic contrasts may be a nonmonotonic function of experience with language. The implications of this idea are discussed. The model also provides a formal framework for studying habituation-dishabituation behaviors in infancy.
Resumo:
Standardisation of microsatellite allele profiles between laboratories is of fundamental importance to the transferability of genetic fingerprint data and the identification of clonal individuals held at multiple sites. Here we describe two methods of standardisation applied to the microsatellite fingerprinting of 429 Theobroma cacao L. trees representing 345 accessions held in the worlds largest Cocoa Intermediate Quarantine facility: the use of a partial allelic ladder through the production of 46 cloned and sequenced allelic standards (AJ748464 to AJ48509), and the use of standard genotypes selected to display a diverse allelic range. Until now a lack of accurate and transferable identification information has impeded efforts to genetically improve the cocoa crop. To address this need, a global initiative to fingerprint all international cocoa germplasm collections using a common set of 15 microsatellite markers is in progress. Data reported here have been deposited with the International Cocoa Germplasm Database and form the basis of a searchable resource for clonal identification. To our knowledge, this is the first quarantine facility to be completely genotyped using microsatellite markers for the purpose of quality control and clonal identification. Implications of the results for retrospective tracking of labelling errors are briefly explored.
Resumo:
Twenty-eight microsatellite primer pairs developed from Fragaria vesca ‘Rügen’ were applied to sixteen accessions representing eight diploid Fragaria species. The number of alleles generated, the power of discrimination and the percentage of accessions where no PCR product could be amplified were calculated for each locus for the thirteen non-F. vesca accessions. A phylogeny was then generated for the species accessions sampled, using the presence or absence of alleles at the polymorphic loci as character states. Despite the problems inherent in phylogeny reconstruction from microsatellite data, the phylogeny showed some congruence with a previously published phylogeny of Fragaria, based on nucleotide sequence data. However, relationships inferred from microsatellite allele data were relatively unresolved and poorly supported. The genetic basis of allelic polymorphisms at specific loci was investigated through direct sequencing of the PCR products amplified by three primer pairs. The potential utility of sequence data generated from microsatellite loci in evolutionary studies of closely related species groups is briefly explored.
Resumo:
A Bayesian approach to analysing data from family-based association studies is developed. This permits direct assessment of the range of possible values of model parameters, such as the recombination frequency and allelic associations, in the light of the data. In addition, sophisticated comparisons of different models may be handled easily, even when such models are not nested. The methodology is developed in such a way as to allow separate inferences to be made about linkage and association by including theta, the recombination fraction between the marker and disease susceptibility locus under study, explicitly in the model. The method is illustrated by application to a previously published data set. The data analysis raises some interesting issues, notably with regard to the weight of evidence necessary to convince us of linkage between a candidate locus and disease.
Resumo:
The visuospatial perceptual abilities of individuals with Williams syndrome (WS) were investigated in two experiments. Experiment I measured the ability of participants to discriminate between oblique and between nonoblique orientations. Individuals with WS showed a smaller effect of obliqueness in response time, when compared to controls matched for nonverbal mental age. Experiment 2 investigated the possibility that this deviant pattern of orientation discrimination accounts for the poor ability to perform mental rotation in WS (Farran, Jarrold, & Gathercole, 2001). A size transformation task was employed, which shares the image transformation requirements of mental rotation, but not the orientation discrimination demands. Individuals with WS performed at the same level as controls. The results suggest a deviance at the perceptual level in WS, in processing orientation, which fractionates from the ability to mentally transform images.
Resumo:
Perirhinal cortex in monkeys has been thought to be involved in visual associative learning. The authors examined rats' ability to make associations between visual stimuli in a visual secondary reinforcement task. Rats learned 2-choice visual discriminations for secondary visual reinforcement. They showed significant learning of discriminations before any primary reinforcement. Following bilateral perirhinal cortex lesions, rats continued to learn visual discriminations for visual secondary reinforcement at the same rate as before surgery. Thus, this study does not support a critical role of perirhinal cortex in learning for visual secondary reinforcement. Contrasting this result with other positive results, the authors suggest that the role of perirhinal cortex is in "within-object" associations and that it plays a much lesser role in stimulus-stimulus associations between objects.