Confined states in two-dimensional flat elliptic quantum dots and elliptic quantum wires

The energy spectrum and corresponding wave functions of a flat quantum dot with elliptic symmetry are obtained exactly. A detailed study is made of the effect of ellipticity on the energy levels and the corresponding wave functions. The analytical behavior of the energy levels in certain limiting cases is obtained.Comment: 8 figures, accepted for publication in Physica

Simplex solid states of SU(N) quantum antiferromagnets

I define a set of wavefunctions for SU(N) lattice antiferromagnets, analogous to the valence bond solid states of Affleck, Kennedy, Lieb, and Tasaki (AKLT), in which the singlets are extended over N-site simplices. As with the valence bond solids, the new simplex solid (SS) states are extinguished by certain local projection operators, allowing us to construct Hamiltonians with local interactions which render the SS states exact ground states. Using a coherent state representation, we show that the quantum correlations in each SS state are calculable as the finite temperature correlations of an associated classical model, with N-spin interactions, on the same lattice. In three and higher dimensions, the SS states can spontaneously break SU(N) and exhibit N-sublattice long-ranged order, as a function of a discrete parameter which fixes the local representation of SU(N). I analyze this transition using a classical mean field approach. For N>2 the ordered state is selected via an "order by disorder" mechanism. As in the AKLT case, the bulk representations fractionalize at an edge, and the ground state entropy is proportional to the volume of the boundary.Comment: 14 pages, 8 figures, minor typos correcte

Modality-specific Affective Responses and their Implications for Affective BCI

Reliable applications of multimodal affective brain-computer interfaces (aBCI) require a detailed understanding of the processes involved in emotions. To explore the modality-specific nature of affective responses, we studied neurophysiological responses of 24 subjects during visual, auditory, and audiovisual affect stimulation and obtained their subjective ratings. Coherent with literature, we found modality-specific responses in the EEG: parietal alpha power decreases during visual stimulation and increases during auditory stimulation, whereas more anterior alpha power decreases during auditory stimulation and increases during visual stimulation. We discuss the implications of these results for multimodal aBCI

Serine, but not glycine, supports one-carbon metabolism and proliferation of cancer cells

Previous work has shown that some cancer cells are highly dependent on serine/glycine uptake for proliferation. Although serine and glycine can be interconverted and either might be used for nucleotide synthesis and one-carbon metabolism, we show that exogenous glycine cannot replace serine to support cancer cell proliferation. Cancer cells selectively consumed exogenous serine, which was converted to intracellular glycine and one-carbon units for building nucleotides. Restriction of exogenous glycine or depletion of the glycine cleavage system did not impede proliferation. In the absence of serine, uptake of exogenous glycine was unable to support nucleotide synthesis. Indeed, higher concentrations of glycine inhibited proliferation. Under these conditions, glycine was converted to serine, a reaction that would deplete the one-carbon pool. Providing one-carbon units by adding formate rescued nucleotide synthesis and growth of glycine-fed cells. We conclude that nucleotide synthesis and cancer cell proliferation are supported by serine—rather than glycine—consumption

Brain computer interfaces as intelligent sensors for enhancing human-computer interaction

BCIs are traditionally conceived as a way to control apparatus, an interface that allows you to act on" external devices as a form of input control. We propose an alternative use of BCIs, that of monitoring users as an additional intelligent sensor to enrich traditional means of interaction. This vision is what we consider to be a grand challenge in the field of multimodal interaction. In this article, this challenge is introduced, related to existing work, and illustrated using some best practices and the contributions it has received

Wood gnawing in mice is not associated with open-field behaviour

The question was addressed whether in two strains of mice the amount chewed off supplied balsa wood is correlated with one of six measured aspects of open-field behaviour. For individual mice there were no significant correlations. This may either relate to a different nature of wood gnawing and open-field behaviour or to the observed low degree of stability of these behaviours in individual animals

Secondary traumatisation and emotional exhaustion in mental healthcare providers:The mediating role of social support

Background: Burnout, especially emotional exhaustion, is common among mental healthcare providers (MHP). It is caused by exposure to prolonged stress related job conditions, such as secondary traumatisation. Social support is a protective factor for developing emotional exhaustion. In addition, higher levels of social support are associated with lower levels of secondary traumatisation. However, it is unclear how social support and secondary traumatisation are related. Social support may be a protective factor for developing secondary traumatisation, as it is for emotional exhaustion. On the other hand, MHP who suffer more from secondary traumatisation might experience less social support, for example because they fear stigmatisation. This study examined whether social support mediates the relationship between secondary traumatisation and emotional exhaustion. Further, it is explored whether the relation between secondary traumatisation and social support is moderated by profession (physicians, psychologists and case managers). Method: In total, 593 MHP participated in this cross-sectional study. Participants completed a questionnaire including demographic characteristics, secondary traumatisation, emotional exhaustion, and social support. Results: It was shown that no MHP experience high levels of secondary traumatisation and relatively few experience high levels of emotional exhaustion, while they do experience much social support. Furthermore, as hypothesized, it was found that the relationship between secondary traumatisation and emotional exhaustion is partially mediated by social support. Finally, no moderation effect of profession was found. Conclusion: These results imply that MHP have access to social support and make use of it, preventing emotional exhaustion. Mental healthcare organisations should maintain these resources for social support to prevent emotional exhaustion. MHP who are less inclined to seek social support should receive extra attention, as should MHP who are more at risk of secondary traumatisation. Even though MHP experience the availability of social support, still 25% of the MHP do experience emotional exhaustion. Future research should examine which factors for this group contribute to the development of emotional exhaustion so that appropriate measures can be taken

Cyclosporin in atopic dermatitis: A multicentre placebo-controlled study

The efficacy of cyclosporin (Sandimmun®) given in a daily dose of 5 mg/kg for 6 weeks in severe atopic dermatitis was confirmed in this double-blind, placebo-controlled, short-term study. Of the 46 patients included in the study, 23 were randomized to receive cyclosporin and 23 to receive placebo. Four of the 23 patients (17%) on cyclosporin, and 14 of the 23 patients (61%) who received placebo, discontinued the trial because of inefficacy. All patients who discontinued the trial were assessed following the principle the principle of ‘intention to treat’. Compared with the baseline, the mean scores for disease severity [6-area, total body severity assessment (TBSA)] improved by 55%, and the mean scores for extent of disease [rule-of-nines area assessment (RoNAA)] improved by 40%, in patients treated with cyclosporin. Nine of the patients who received cyclosporin and completed the study (n=14) had an individual reduction of disease severity (TBSA) of 75% or more, and in three patients this reduction was nearly 100%. In the placebo group, a mean worsening of disease severity (4%) and of extent of the disease (25%), compared with the baseline, was observed al week 6. Patients' and investigators' mean scores for the overall efficacy were similar, and showed a statistically significant difference in favour of cyclosporin. Two patients on cyclosporin developed hypertension during therapy, and one of these withdrew from the study. At the end of the trial, no statistically significant differences in the systolic or diastolic blood pressures were observed between the two groups. In the cyclosporin group, the increases in the values of serum creatinine and bilirubin at week 6, compared with the respective values at the baseline, were statistically significantly different from those in the placebo group, but all values normalized in the post-treatment period. Cyclosporin can be a safe and very effective treatment in episodes of severe atopic dermatitis, provided that the recommended guidelines for its administration are strictly observed

Effect of spatially varying material properties on the post-buckling behaviour of composite panels utilising geodesic stochastic fields

The post-buckling behaviour of panels can be very sensitive to imperfections or variations in materials or geometry. This paper presents an ecient numerical model to calculate the eects of material stiffness variations on the non-linear response of a structure. This is done by first defining a geodesic mesh on which a unit variance random field is generated. This field uses the true geodesic distance on the structure to calculate how points in the field should be correlated. The fields generated are projected onto a 3D structural mesh which is used for assembly and post-processing of the structural model. The structural model, based on the Unified Formulation is capable of accurate non-linear calculations of both straight and curved elements. Baseline results generated using the implementation are compared to those in literature, and verified using Abaqus. Random material variations are then applied to the structure in a Monte Carlo analysis. The analyses show that the local variation of stiffness can have a variety of effects on the non-linear response of structures. Aside from the change of mean stiffness causing a change in bifurcation or limit point load, the different stiffness distributions can affect and trigger competing buckling modes and post-buckling modes and affect their corresponding post-buckling load-deflection paths