6,864 research outputs found

    Williams Syndrome: The extent of agreement between parent and self report of psychological

    Get PDF
    Background and Objectives: People with Williams syndrome (WS) have been reported by their carers to have problems with attention, anxiety and social relationships. People with WS have been shown to report their anxieties. This study extends our knowledge of how people with WS see themselves in terms of behaviour and social relationships. Methods: A survey using self and parent report forms of the Strengths and Difficulties Questionnaire. Results: Both parents and individuals with WS (N = 31) reported difficulties in emotional disorder and hyperactivity symptoms and strengths in prosocial behaviours such as altruism and empathy. They disagreed about peer problems. Conclusions: People with WS understand some but not all of their difficulties. In particular they fail to recognize their social difficulties which may lead them to be vulnerable to exploitation.</p

    Pseudogap, Superconducting Energy Scale, and Fermi Arcs in Underdoped Cuprate Superconductors

    Full text link
    Through the measurements of magnetic field dependence of specific heat in La2xSrxCuO4La_{2-x}Sr_xCuO_4 in zero temperature limit, we determined the nodal slope vΔv_\Delta of the quasiparticle gap. It is found that vΔv_\Delta has a very similar doping dependence of the pseudogap temperature TT^* or value Δp\Delta_p. Meanwhile the virtual maximum gap at (π,0\pi,0) derived from vΔv_\Delta is found to follow the simple relation Δq=0.46kBT\Delta_q=0.46k_BT^* upon changing the doping concentration. This strongly suggests a close relationship between the pseudogap and superconductivity. It is further found that the superconducting transition temperature is determined by both the residual density of states of the pseudogap phase and the nodal gap slope in the zero temperature limit, namely, TcβvΔγn(0)T_c \approx \beta v_\Delta \gamma_n(0), where γn(0)\gamma_n(0) is the extracted zero temperature value of the normal state specific heat coefficient which is proportional to the size of the residual Fermi arc karck_{arc}. This manifests that the superconductivity may be formed by forming a new gap on the Fermi arcs near nodes below TcT_c. These observations mimic the key predictions of the SU(2) slave boson theory based on the general resonating-valence-bond (RVB) picture.Comment: 6 pages, 6 figures, to be published in Phys. Rev.

    Electronic specific heat and low energy quasiparticle excitations in superconducting state of La2xSrxCuO4La_{2-x}Sr_xCuO_4 single crystals

    Full text link
    Low temperature specific heat has been measured and extensively analyzed on a series of La2xSrxCuO4La_{2-x}Sr_xCuO_4 single crystals from underdoped to overdoped regime. From these data the quasiparticle density of states (DOS) in the mixed state is derived and compared to the predicted scaling law Cvol/TH=f(T/H)C_{vol}/T\sqrt{H}=f(T/\sqrt{H}) of d-wave superconductivity. It is found that the scaling law can be nicely followed by the optimally doped sample (x=0.15) in quite wide region of (T/H8K/TT/\sqrt{H} \leq 8 K /\sqrt{T}). However, the region for this scaling becomes smaller and smaller towards more underdoped region: a clear trend can be seen for samples from x=0.15 to 0.069. Therefore, generally speaking, the scaling quality becomes worse on the underdoped samples in terms of scalable region of T/HT/\sqrt{H}. This feature in the underdoped region is explained as due to the low energy excitations from a second order (for example, anti-ferromagnetic correlation, d-density wave, spin density wave or charge density wave order) that may co-exist or compete with superconductivity. Surprisingly, deviations from the d-wave scaling law have also been found for the overdoped sample (x=0.22). While the scaling law is reconciled for the overdoped sample when the core size effect is taken into account. An important discovery of present work is that the zero-temperature data follow the Volovik's relation Δγ(T=0)=AH\Delta \gamma(T=0)=A\sqrt{H} quite well for all samples investigated here although the applicability of the d-wave scaling law to the data at finite temperatures varies with doped hole concentration. Finally we present the doping dependence of some parameters, such as, the residual linear term γ0\gamma_0, the α\alpha value, etc. ...Comment: 15 pages, 24 figure

    Cancers attributable to overweight and obesity from 2012 to 2014 in Nigeria: A population-based cancer registry study

    Get PDF
    Background: Overweight and obesity are known risk factors for chronic diseases including cancers. In this study, we evaluated the age standardized incidence rates (ASR) and proportion of cancers attributable to overweight and obesity in Nigeria. Methods: We obtained incidence data from the databases of two population-based cancer registries (PBCRs) in Nigeria (Abuja and Enugu cancer registries), on cancer site for which there is established evidence of an association with overweight or obesity based on the International Agency for Research on Cancer (IARC) and the World Cancer Research Fund (WCRF) classification. We analyzed the data using population attributable fraction (PAF) for overweight or obesity associated cancers calculated using prevalence data and relative risk estimates in previous studies. Results: The two PBCRs reported 4,336 new cancer cases (ASR 113.9 per 100,000) from 2012 to 2014. Some 21% of these cancers were associated with overweight and obesity. The ASR for overweight and obesity associated cancers was 24.5 per 100,000; 40.7 per 100,000 in women and 8.2 per 100,000 in men. Overall, only 1.4% of incident cancers were attributable to overweight and obesity. The ASR of cancers attributable to overweight and obesity was 2.0 per 100,000. Postmenopausal breast cancer was the most common cancer attributable to overweight and obesity (n = 25; ASR 1.2 per 100,000). Conclusion: Our results suggest that a small proportion of incident cancer cases in Nigeria are potentially preventable by maintaining normal body weight. The burden of cancer attributed to overweight and obesity in Nigeria is relatively small, but it may increase in future

    Monitoring the process of formation of ZnO from ZnO2 using in situ combined XRD/XAS technique

    Get PDF
    Use of in situ combined X-ray diffraction and X-ray absorption spectroscopy for the study of the thermal decomposition of zinc peroxide to zinc oxide is reported here. Comparison of data extracted from both X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) with thermo gravimetric analysis (TGA) enabled us to follow the nature of the conversion of ZnO2 to ZnO. A temperature range between 230 and 350oC appears to show a very poorly crystalline ZnO is formed prior to the formation of ordered ZnO material. Both the decrease in white line intensity in the Zn K-edge XANES and resulting lower coordination numbers estimated from analysis of Zn K-edge data of ZnO heated at 500oC, in comparison to bulk ZnO, suggest that that the ZnO produced by this method has significant defects in the system

    Repeated cocaine exposure decreases dopamine D2-like receptor modulation of Ca2+ homeostasis in rat nucleus accumbens neurons

    Get PDF
    The nucleus accumbens is a limbic structure in the forebrain which plays a critical role in cognitive function and addiction.  Dopamine modulates activity of medium spiny neurons in the nucleus accumbens.  Both dopamine D1-like and D2-like receptors (including D1R or D1,5R, and D2R or D2,3,4R, respectively) are thought to play critical roles in cocaine addiction.  Our previous studies demonstrated that repeated cocaine exposure (which alters dopamine transmission) decreases excitability of nucleus accumbens medium spiny neurons in cocaine-sensitized, withdrawn rats.  This decrease is characterized by a reduction in voltage-sensitive Na+ currents and high voltage-activated Ca2+ currents, along with increased voltage-gated K+ currents.  These changes are associated with enhanced activity in the D1R/cAMP/PKA/protein phosphatase 1 pathway and diminished calcineurin function.  Though D1R-mediated signaling is enhanced by repeated cocaine exposure, little is known whether and how the D2R is implicated in the cocaine-induced nucleus accumbens dysfunction.  Here, we performed a combined electrophysiological, biochemical, and neuroimaging study that reveals the cocaine-induced dysregulation of Ca2+ homeostasis with involvement of D2R.  Our novel findings reveal that D2R stimulation reduced Ca2+ influx preferentially via the L-type Ca2+ channels and evoked intracellular Ca2+ release, likely via inhibiting the cAMP/PKA cascade, in the nucleus accumbens medium spiny neurons of drug-free rats.  However, repeated cocaine exposure abolished the D2R effects on modulating Ca2+ homeostasis with enhanced PKA activity and led to a decrease in whole-cell Ca2+ influx.  These adaptations, which persisted for 21 days during cocaine abstinence, may contribute to the mechanism of cocaine withdrawal.Fil: Perez, Mariela Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Farmacología Experimental de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Farmacología Experimental de Córdoba; ArgentinaFil: Ford, Kerstin A.. Rosalind Franklin University of Medicine and Science; Estados UnidosFil: Goussakov, Ivan. Rosalind Franklin University of Medicine and Science; Estados UnidosFil: Stutzmann, Grace E.. Rosalind Franklin University of Medicine and Science; Estados UnidosFil: Hu, Xiu-Ti. Rush University Medical Center; Estados Unido

    Comparison of statistical approaches to rare variant analysis for quantitative traits

    Get PDF
    With recent advances in technology, deep sequencing data will be widely used to further the understanding of genetic influence on traits of interest. Therefore not only common variants but also rare variants need to be better used to exploit the new information provided by deep sequencing data. Recently, statistical approaches for analyzing rare variants in genetic association studies have been proposed, but many of them were designed only for dichotomous outcomes. We compare the type I error and power of several statistical approaches applicable to quantitative traits for collapsing and analyzing rare variant data within a defined gene region. In addition to comparing methods that consider only rare variants, such as indicator, count, and data-adaptive collapsing methods, we also compare methods that incorporate the analysis of common variants along with rare variants, such as CMC and LASSO regression. We find that the three methods used to collapse rare variants perform similarly in this simulation setting where all risk variants were simulated to have effects in the same direction. Further, we find that incorporating common variants is beneficial and using a LASSO regression to choose which common variants to include is most useful when there is are few common risk variants compared to the total number of risk variants
    corecore