Three-body correlations in a two-dimensional SU(3) Fermi gas

We consider a three-component Fermi gas that has SU(3) symmetry and is confined to two dimensions (2D). For realistic cold atomic gas experiments, we show that the phase diagram of the quasi-2D system can be characterized using two 2D scattering parameters: the scattering length and the effective range. Unlike the case in 3D, we argue that three-body bound states (trimers) in the quasi-2D system can be stable against three-body losses. Using a low-density expansion coupled with a variational approach, we investigate the fate of such trimers in the many-body system as the attractive interactions are decreased (or, conversely, as the density of particles is increased). We find that remnants of trimers can persist in the form of strong three-body correlations in the weak-coupling (high-density) limit.Comment: 13 pages, 4 figure

A reinforcing circuit action of extrasynaptic GABAA receptor modulators on cerebellar granule cell inhibition.

GABAA receptors (GABARs) are the targets of a wide variety of modulatory drugs which enhance chloride flux through GABAR ion channels. Certain GABAR modulators appear to acutely enhance the function of δ subunit-containing GABAR subtypes responsible for tonic forms of inhibition. Here we identify a reinforcing circuit mechanism by which these drugs, in addition to directly enhancing GABAR function, also increase GABA release. Electrophysiological recordings in cerebellar slices from rats homozygous for the ethanol-hypersensitive (α6100Q) allele show that modulators and agonists selective for δ-containing GABARs such as THDOC, ethanol and THIP (gaboxadol) increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in granule cells. Ethanol fails to augment granule cell sIPSC frequency in the presence of glutamate receptor antagonists, indicating that circuit mechanisms involving granule cell output contribute to ethanol-enhancement of synaptic inhibition. Additionally, GABAR antagonists decrease ethanol-induced enhancement of Golgi cell firing. Consistent with a role for glutamatergic inputs, THIP-induced increases in Golgi cell firing are abolished by glutamate receptor antagonists. Moreover, THIP enhances the frequency of spontaneous excitatory postsynaptic currents in Golgi cells. Analyses of knockout mice indicate that δ subunit-containing GABARs are required for enhancing GABA release in the presence of ethanol and THIP. The limited expression of the GABAR δ subunit protein within the cerebellar cortex suggests that an indirect, circuit mechanism is responsible for stimulating Golgi cell GABA release by drugs selective for extrasynaptic isoforms of GABARs. Such circuit effects reinforce direct actions of these positive modulators on tonic GABAergic inhibition and are likely to contribute to the potent effect of these compounds as nervous system depressants

Changes in Purkinje cell firing and gene expression precede behavioral pathology in a mouse model of SCA2.

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominantly inherited disorder, which is caused by a pathological expansion of a polyglutamine (polyQ) tract in the coding region of the ATXN2 gene. Like other ataxias, SCA2 most overtly affects Purkinje cells (PCs) in the cerebellum. Using a transgenic mouse model expressing a full-length ATXN2(Q127)-complementary DNA under control of the Pcp2 promoter (a PC-specific promoter), we examined the time course of behavioral, morphologic, biochemical and physiological changes with particular attention to PC firing in the cerebellar slice. Although motor performance began to deteriorate at 8 weeks of age, reductions in PC number were not seen until after 12 weeks. Decreases in the PC firing frequency first showed at 6 weeks and paralleled deterioration of motor performance with progression of disease. Transcription changes in several PC-specific genes such as Calb1 and Pcp2 mirrored the time course of changes in PC physiology with calbindin-28 K changes showing the first small, but significant decreases at 4 weeks. These results emphasize that in this model of SCA2, physiological and behavioral phenotypes precede morphological changes by several weeks and provide a rationale for future studies examining the effects of restoration of firing frequency on motor function and prevention of future loss of PCs

The relationship between taste sensitivity to phenylthiocarbamide and anhedonia

It has been proposed that taste sensitivity to bitter compounds such as, phenylthiocarbamide (PTC) and 6 n-propylthiouracil (PROP), represents a genetic marker for an increased vulnerability to depressive illness. Previous explorations of this idea have proven equivocal. This study refines and further explores this idea by focusing specifically on anhedonia (diminished hedonic capacity), a key symptom in some depressive illness, linked also with sensory pleasure. It is hypothesized that diminished PTC taste sensitivity will be associated with more general decrements in hedonic capacity (anhedonia). An opportunity sample of 198 university students were assessed using paper strips impregnated with PTC, the same participants also completed a widely used assessment of hedonic capacity, the Snaith-Hamilton Pleasure Scale (SHAPS). Hedonic capacity scores positively correlated with PTC taste sensitivity; specifically, heightened hedonic capacity was associated with heightened sensitivity to the bitter taste of PTC. Furthermore, modest differences were observed between those least (non-tasters) and most (supertasters) sensitive to PTC, with non-tasters reporting significantly lower hedonic capacity scores than supertasters. PTC taste sensitivity may represent a peripheral risk factor for anhedonia. © 2013 Elsevier Ireland Ltd

Religiosity: Reducing Depressive Symptoms Amongst Muslim Females in the United Arab Emirates

Religiosity has previously been associated with greater wellbeing, as well as with lower rates of depressive disorders and less severe levels of depressive symptoms. Relatively few studies however, have explored this association in Muslim populations. The present study explores the relationship between religiosity and depressive symptoms amongst female citizens of the United Arab Emirates. Using a cross-sectional correlational design, a convenience sample of college students (N = 459) completed the Religious Conviction Inventory (RCI-10), adapted to the Islamic context, along with the Beck Depression Inventory (BDI-II). Both instruments demonstrated good psychometric properties and as hypothesized, religiosity was negatively correlated with depressive symptoms. Further, individuals categorized as experiencing severe depressive symptoms reported significantly lower levels of religiosity, compared to their asymptomatic counterparts. These findings lend further support to the idea that religiosity may act as a resilience-factor in the context of depression, extending this idea to female citizens of the United Arab Emirates. The findings of this study are understood in the context of the second wave of positive psychology, called PP 2.0, which looks at positive and negative factors in individual\u27s lives as both interact to produce positive clinical outcomes

Carotenoid, Vitamin A, Vitamin C, and Vitamin E Intake and Risk of Ovarian Cancer: a Prospective Cohort Study

It is thought that oxidative stress resulting to repeated ovulation may increase the risk of ovarian cancer by inducing DNA damage (1). Consumption of antioxidants may, therefore, decrease ovarian cancer risk by counteracting oxidative stress and the resultant DNA damage (2, 3). Currently, the epidemiologic evidence regarding associations between antioxidants and risk of ovarian cancer is mixed (4-12). Of the two prospective studies, Kushi et al. (4) and Fairfield et al. (7) both reported no association between β-carotene and ovarian cancer risk. In addition, Fairfield et al. (7) found no association with any of the other four major carotenoids (α-carotene, β-cryptoxanthin, lycopene, and lutein) or vitamins A or C. However, they did observe a statistically significant increased risk of ovarian cancer associated with relatively high intake of vitamin E from food sources (7). Given the current lack of prospective data regarding these relationships, we examined the association between intake of dietary carotenoids and vitamins A, C, and E and ovarian cancer risk in a cohort of Canadian women

GRAPHENE BASED MATERIALS FOR SUPERCAPACITORS

The adoption of more environmental friendly means of harnessing and storing energy while minimizing harmful effects on the environment is becoming more significant. Supercapacitors are becoming a more favored means of energy storage systems owing to their higher surface area electrodes and thinner dielectrics. For greater capacitances, a suitable material must have high porosity. Such a suitable material is carbon, most notably graphene, with superior electrical properties, chemical stability and high surface area. This review focuses on the types of mechanism for storing energy, the types of materials used in supercapacitors, and the applications and scope of supercapacitor research and development