Large deviations for ideal quantum systems

We consider a general d-dimensional quantum system of non-interacting particles, with suitable statistics, in a very large (formally infinite) container. We prove that, in equilibrium, the fluctuations in the density of particles in a subdomain of the container are described by a large deviation function related to the pressure of the system. That is, untypical densities occur with a probability exponentially small in the volume of the subdomain, with the coefficient in the exponent given by the appropriate thermodynamic potential. Furthermore, small fluctuations satisfy the central limit theorem.Comment: 28 pages, LaTeX 2

Allele mining in solanum: conserved homologues of Rpi-blb 1 are identified in Solanum stoloniferum

Allele mining facilitates the discovery of novel resistance (R) genes that can be used in breeding programs and sheds light on the evolution of R genes. Here we focus on two R genes, Rpi-blb1 and Rpi-blb2, originally derived from Solanum bulbocastanum. The Rpi-blb1 gene is part of a cluster of four paralogues and is flanked by RGA1-blb and RGA3-blb. Highly conserved RGA1-blb homologues were discovered in all the tested tuber-bearing (TB) and non-tuber-bearing (NTB) Solanum species, suggesting RGA1-blb was present before the divergence of TB and NTB Solanum species. The frequency of the RGA3-blb gene was much lower. Interestingly, highly conserved Rpi-blb1 homologues were discovered not only in S. bulbocastanum but also in Solanum stoloniferum that is part of the series Longipedicellata. Resistance assays and genetic analyses in several F1 populations derived from the relevant late blight resistant parental genotypes harbouring the conserved Rpi-blb1 homologues, indicated the presence of four dominant R genes, designated as Rpi-sto1, Rpi-plt1, Rpi-pta1 and Rpi-pta2. Furthermore, Rpi-sto1 and Rpi-plt1 resided at the same position on chromosome VIII as Rpi-blb1 in S. bulbocastanum. Segregation data also indicated that an additional unknown late blight resistance gene was present in three populations. In contrast to Rpi-blb1, no homologues of Rpi-blb2 were detected in any material examined. Hypotheses are proposed to explain the presence of conserved Rpi-blb1 homologues in S. stoloniferum. The discovery of conserved homologues of Rpi-blb1 in EBN 2 tetraploid species offers the possibility to more easily transfer the late blight resistance genes to potato varieties by classical breeding

Scenemash: Multimodal Route Summarization for City Exploration

The potential of mining tourist information from social multimedia data gives rise to new applications offering much richer impressions of the city. In this paper we propose Scenemash, a system that generates multimodal summaries of multiple alternative routes between locations in a city. To get insight into the geographic areas on the route, we collect a dataset of community-contributed images and their associated annotations from Foursquare and Flickr. We identify images and terms representative of a geographic area by jointly analysing distributions of a large number of semantic concepts detected in the visual content and latent topics extracted from associated text. Scenemash prototype is implemented as an Android app for smartphones and smartwatches

Factors contributing to the negation of therapeutic services by emerging adults at a South African university

From a practice point of view it seems as if there are certain factors that might contribute to the fact that emerging adults tend to negate therapeutic help and services. It also seems to be specifically true with regard to emerging adults at university. Help negation seems to occur albeit the fact that therapeutic intervention is seen as an effective tool in managing distress. The aim of the study therefore was to explore which factors contribute to help negation behaviour in emerging adults at a specific university in South Africa.A qualitative case study design was employed where participants who complied with the inclusion criteria set out for the study, were selected by means of non-probability target and snowball sampling. Fifteen students residing in campus residences respectively participated in one of three focus group discussions. Creswell’s spiral of data analysis was used to analyse the transcribed data.The data crystallised into four themes, which contribute to help negation behaviour in emerging adults. Emerging adults have a fear of being judged, stigmatised, recognised, of not being treated confidentially and a fear of being vulnerable and hurt. They prefer to seek help and support from their family and peers and to put their trust in God and their religion; they have internalised beliefs about themselves and therapy and a need for independence; student interns work at the therapeutic centres on campus which specifically contributes to help negation for emerging adults at the university. It is crucial that the professionals revisit their strategies and approaches in order to overcome negation of formal help and create a more understandable, approachable and effective therapeutic service to emerging adults, especially at university therapeutic centres

High orders of Weyl series for the heat content

This article concerns the Weyl series of spectral functions associated with the Dirichlet Laplacian in a $d$-dimensional domain with a smooth boundary. In the case of the heat kernel, Berry and Howls predicted the asymptotic form of the Weyl series characterized by a set of parameters. Here, we concentrate on another spectral function, the (normalized) heat content. We show on several exactly solvable examples that, for even $d$, the same asymptotic formula is valid with different values of the parameters. The considered domains are $d$-dimensional balls and two limiting cases of the elliptic domain with eccentricity $\epsilon$: A slightly deformed disk ($\epsilon\to 0$) and an extremely prolonged ellipse ($\epsilon\to 1$). These cases include 2D domains with circular symmetry and those with only one shortest periodic orbit for the classical billiard. We analyse also the heat content for the balls in odd dimensions $d$ for which the asymptotic form of the Weyl series changes significantly.Comment: 20 pages, 1 figur

Warehouse design and planning: A mathematical programming approach

The dynamic nature of today's competitive markets compels organizations to an incessant reassessment in an effort to respond to continuous challenges. Therefore, warehouses as an important link in most supply chains, must be continually re-evaluated to ensure that they are consistent with both market's demands and management's strategies. A number of warehouse decision support models have been proposed in the literature but considerable difficulties in applying these models still remain, due to the large amount of information to be processed and to the large number of possible alternatives. In this paper we discuss a mathematical programming model aiming to support some warehouse management and inventory decisions. In particular a large mixed-integer nonlinear programming model (MINLP) is presented to capture the trade-offs among the different inventory and warehouse costs in order to achieve global optimal design satisfying throughput requirements.(undefined)info:eu-repo/semantics/publishedVersio

English medium of instruction: A situation analysis

The majority of learners in southern Africa receive their education through the medium of a second language, English. Although teachers of English play a crucial role in helping learners to acquire language skills in the medium of instruction, we argue that subject content teachers' lack of attention to the teaching of the four language skills may be a raison d'être for learners' lack of academic achievement. A situation analysis conducted among three study populations examined the extent to which subject content teachers took responsibility for the teaching of language skills in the content classroom, as well as possible reasons for not doing so. It also shed some light on the amount of language teaching that actually took place in a content classroom. The aim of the situation analysis was to determine whether there was a need for a specialised training course for English second language medium of instruction teachers.South African Journal of Education Vol. 27 (1) 2007: pp. 69-8

Perpendicular transport and magnetization processes in magnetic multilayers with strongly and weakly coupled magnetic layers

Within the framework of a two-band tight-binding model, we have performed calculations of giant magnetoresistance, exchange coupling and thermoelectric power (TEP) for a system consisting of three magnetic layers separated by two non-magnetic spacers with the first two magnetic layers strongly antiferromagnetically exchange-coupled. We have shown how does the GMR relate with the corresponding regions of magnetic structure phase diagrams and computed some relevant hysteresis loops, too. The GMR may take negative values for specific layers thicknesses, and the TEP reveals quite pronounced oscillations around a negative bias.Comment: 16 pages, 10 figures, submited to Journal of Magnetism and Magnetic Material