19,210 research outputs found
High-Precision Entropy Values for Spanning Trees in Lattices
Shrock and Wu have given numerical values for the exponential growth rate of
the number of spanning trees in Euclidean lattices. We give a new technique for
numerical evaluation that gives much more precise values, together with
rigorous bounds on the accuracy. In particular, the new values resolve one of
their questions.Comment: 7 pages. Revision mentions alternative approach. Title changed
slightly. 2nd revision corrects first displayed equatio
Kinetics and Inhibition Studies of the L205R Mutant of cAMP-Dependent Protein Kinase Involved in Cushingās Syndrome
Overproduction of cortisol by the hypothalamusāpituitaryāadrenal hormone system results in the clinical disorder known as Cushing\u27s syndrome. Genomics studies have identified a key mutation (L205R) in the Ī±āisoform of the catalytic subunit of cAMPādependent protein kinase (PKACĪ±) in adrenal adenomas of patients with adrenocorticotropic hormoneāindependent Cushing\u27s syndrome. Here, we conducted kinetics and inhibition studies on the L205RāPKACĪ± mutant. We have found that the L205R mutation affects the kinetics of both Kemptide and ATP as substrates, decreasing the catalytic efficiency (kcat/KM) for each substrate by 12āfold and 4.5āfold, respectively. We have also determined the IC50 and Ki for the peptide substrateācompetitive inhibitor PKI(5ā24) and the ATPācompetitive inhibitor H89. The L205R mutation had no effect on the potency of H89, but causes a \u3e 250āfold loss in potency for PKI(5ā24). Collectively, these data provide insights for the development of L205RāPKACĪ± inhibitors as potential therapeutics
What is past is prologue: Pre-natal testosterone and parental bonding predicts adult attachment styles
Research consistently evidences deleterious consequences of poor parenting in the development of dysfunctional and antisocial behaviours in children (Jaffee et al., 2005). For example, foetal development is affected by the psychological and physical health of the mother. Indeed, maternal smoking increases in utero testosterone (Rizwan et al., 2007), which is associated with aggression (Bailey & Hurd, 2005), risk-taking (Stenstrom et al., 2010) and dom- inant (Millet, 2011) behaviours. However, interactions such as these may offer survival advantage to offspring within hostile environments (Belsky, Steinberg & Draper, 1991). We investigated relationships between prenatal testosterone (2D:4D ratio), perception of quality of parental bonding and adult attachment style. As expected, low maternal warmth and high levels of prenatal testosterone predicted anxious attachment, while the addition of maternal over-controlling to this model predicted avoidant attachment. This evidences how changes in hormonal level might equip an unborn child to survive more successfully within a prospective adversarial environment
Microwave properties of DyBa_2Cu_3O_(7-x) monodomains and related compounds in magnetic fields
We present a microwave characterization of a DyBaCuO
single domain, grown by the top-seeded melt-textured technique. We report the
(a,b) plane field-induced surface resistance, , at 48.3 GHz,
measured by means of a cylindrical metal cavity in the end-wall-replacement
configuration. Changes in the cavity quality factor Q against the applied
magnetic field yield at fixed temperatures. The temperature
range [70 K ; T_c] was explored. The magnetic field 0.8 T was
applied along the c axis. The field dependence of does not
exhibit the steep, step-like increase at low fields typical of weak-links. This
result indicates the single-domain character of the sample under investigation.
exhibits a nearly square-root dependence on H, as expected for
fluxon motion. From the analysis of the data in terms of motion of Abrikosov
vortices we estimate the temperature dependences of the London penetration
depth and the vortex viscosity , and their zero-temperature
values 165 nm and 3 10 Nsm, which are
found in excellent agreement with reported data in YBaCuO
single crystals. Comparison of microwave properties with those of related
samples indicate the need for reporting data as a function of T/T_c in order to
obtain universal laws.Comment: 6 pages, 4 figures, LaTeX, submitted to Journal of Applied Physic
Mine is Bigger than Yours! Narcissism Predicts Biases in Perceived Head Size
The expression big headed is often used to describe narcissists, however is it possible that this term signals a bias in how narcissists perceive themselves? We tested whether narcissistic traits predicted biases in the estimated size and weight of specific body parts, including head circumference and brain weight. In two questionnaire-based studies, participants estimated the size or weight of parts of their body. In Study 1 (n = 316), we found that the Leadership/Authority facet of narcissism significantly predicted greater estimates of head circumference in men, but lower estimates of head circumference in women. In Study 2 (n = 275), we found that when a sex-specific average head circumference was not provided, Leadership/Authority predicted greater estimates of head circumference overall. We present evidence that narcissism predicts biases in estimated head size and brain weight, but that the precise nature of these biases is dependent on the provided frame of reference for body size. These results are discussed with reference to within-sex competitive strategies, perceived intelligence and stereotypes for male and female attractiveness
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