Stock margins and the condition probability of price reversals

Does the cost of trading affect stock prices? Yes, according to the evidence in this article. The authors find that high costs seem to reduce the frequency of price reversals.Stocks ; Stock - Prices

EXPLORING THE EFFECT OF 8 WEEKS OF CANNABIDIOL ON SERUM BRAIN-DERIVED NEUROTROPHIC FACTOR

Studies have shown that cannabidiol (CBD) consumption may lead to neuroprotective effects. Brain-derived neurotrophic factor (BDNF) is a circulating biomarker of neural health and studies exploring the effects of CBD on BDNF concentrations are limited. Purpose: The purpose of this study is to determine whether a longer-term CBD intervention would significantly change BDNF concentrations in human serum. Methods: This study used a double-blind placebo-controlled design where thirty-five healthy adult participants were randomly assigned into two groups. Participants were 25.94 ± 6.5 years of age with a body weight of 72.35 ± 13.89 kg and a body fat percentage of 22.61 ± 7.95%. One group (CB, n=18) ingested a 50mg CBD gel capsule orally once a day for 8 weeks while the control group (PL, n=17) group consumed a calorie-matched placebo (PL) over the course of the same 8-week period. At pre intervention and post intervention time points, participant body size, body composition was obtained. Blood was also collected at both time points and serum was used to determine BDNF concentration using an enzyme-linked immunosorbent assay (ELISA). An ANOVA was used to determine whether there were differences at the pre-intervention time point and the way CB and PL groups responded to the intervention. Significance was set at p \u3c 0.05. Results: There were no differences between groups at the pre-intervention time points or as a result of the intervention. Mean concentrations of BDNF at the pre-intervention time point were 25.35 ± 7.3 ng/ml and 23.03 ± 5.2 ng/ml in the PL and CB groups, respectively. Conclusion: Eight weeks of daily, low-dose CBD does not improve BDNF concentrations in healthy people. Future studies may want to explore a higher dose in individuals with impaired neural health

ISW effect in Unified Dark Matter Scalar Field Cosmologies: an analytical approach

We perform an analytical study of the Integrated Sachs-Wolfe (ISW) effect within the framework of Unified Dark Matter models based on a scalar field which aim at a unified description of dark energy and dark matter. Computing the temperature power spectrum of the Cosmic Microwave Background anisotropies we are able to isolate those contributions that can potentially lead to strong deviations from the usual ISW effect occurring in a $\Lambda$CDM universe. This helps to highlight the crucial role played by the sound speed in the Unified Dark Matter models. Our treatment is completely general in that all the results depend only on the speed of sound of the dark component and thus it can be applied to a variety of unified models, including those which are not described by a scalar field but relies on a single dark fluid.Comment: 15 pages, LateX file; one comment after Eq.(36) and formula (44) added in order to underline procedure and main results. Accepted for publication in JCAP; some typos correcte

China and the internationalisation of the sociology of contemporary work and employment

The China e-Special Issue brings together 11 articles on the sociology of contemporary work and employment in China which have been published in WES in the past two decades, highlighting the increasing frequency of submissions, and also reflecting the diversity, complexity and plurality of work and employment in the region. The foci of debates include the changing fault lines of work and employment; the changing relationships between state, employers and workers; the impact of rural to urban migration and urbanisation on the labour process and employment configurations; the interrelations between production and social reproduction and its gendered dimensions; and the need to develop established methodologies further given the changing nature of the research subject

Some Remarks on Oscillating Inflation

In a recent paper Damour and Mukhanov describe a scenario where inflation may continue during the oscillatory phase. This effect is possible because the scalar field spends a significant fraction of each period of oscillation on the upper part of the potential. Such additional period of inflation could push perturbations after the slow roll regime to observable scales. Although in this work we show that the small region of the Damour-Mukhanov parameter q gives the main contribution to oscillating inflation, it was not satisfactory understood until now. Furthermore, it gives an expression for the energy density spectrum of perturbations, which is well behaved in the whole physical range of q .Comment: 4 pages including figures caption, 3 ps-figures. To appear in Phys. Rev.

Topological Defects Formation after Inflation on Lattice Simulation

We consider the formation of topological defects after inflation. In order to take into account the effects of the rescattering of fluctuations, we integrate the classical equation that describes the evolution of a complex scalar field on the two-dimensional lattice with a slab symmetry. The growth of fluctuations during preheating is found not to be enough for defect formation, and rather a long stage of the rescattering of fluctuations after preheating is necessary. We conclude that the topological defects are not formed if the breaking scale \eta is lager than \sim (2 - 3)\times 10^{16} GeV.Comment: 7 pages, RevTex, 10 postscript figures included; version to be published in Phys. Rev.

The Development of Equilibrium After Preheating

We present a fully nonlinear study of the development of equilibrium after preheating. Preheating is the exponentially rapid transfer of energy from the nearly homogeneous inflaton field to fluctuations of other fields and/or the inflaton itself. This rapid transfer leaves these fields in a highly nonthermal state with energy concentrated in infrared modes. We have performed lattice simulations of the evolution of interacting scalar fields during and after preheating for a variety of inflationary models. We have formulated a set of generic rules that govern the thermalization process in all of these models. Notably, we see that once one of the fields is amplified through parametric resonance or other mechanisms it rapidly excites other coupled fields to exponentially large occupation numbers. These fields quickly acquire nearly thermal spectra in the infrared, which gradually propagates into higher momenta. Prior to the formation of total equilibrium, the excited fields group into subsets with almost identical characteristics (e.g. group effective temperature). The way fields form into these groups and the properties of the groups depend on the couplings between them. We also studied the onset of chaos after preheating by calculating the Lyapunov exponent of the scalar fields.Comment: 15 pages, 23 figure

Cosmological perturbations from inhomogeneous preheating and multi-field trapping

We consider inhomogeneous preheating in a multi-field trapping model. The curvature perturbation is generated by inhomogeneous preheating which induces multi-field trapping at the enhanced symmetric point (ESP), and results in fluctuation in the number of e-foldings. Instead of considering simple reheating after preheating, we consider a scenario of shoulder inflation induced by the trapping. The fluctuation in the number of e-foldings is generated during this weak inflationary period, when the additional light scalar field is trapped at the local maximum of its potential. The situation may look similar to locked or thermal inflation or even to hybrid inflation, but we will show that the present mechanism of generating the curvature perturbation is very different from these others. Unlike the conventional trapped inflationary scenario, we do not make the assumption that an ESP appears at some unstable point on the inflaton potential. This assumption is crucial in the original scenario, but it is not important in the multi-field model. We also discuss inhomogeneous preheating at late-time oscillation, in which the magnitude of the curvature fluctuation can be enhanced to accommodate low inflationary scale.Comment: 18pages, 2 figures, to appear in JHE

Gendered dynamics of transnational social protection

Social protection refers to resources and strategies to deal with social risks, such as poverty or obligations and needs of care, which might impede the realization of life chances and well-being. Previous research has shown that migrants are particularly affected by challenges when accessing or providing social protection, because of unfamiliar welfare regulations in the immigration country and their family and friends being located in various locations, calling for an investigation of gendered dynamics in transnational spaces. In this special issue we aim to advance these vital debates by elucidating the social consequences of the articulation and organization of formal and informal social protection across borders for different actors involved through a joint investigation of gender and transnationality as key dimensions of social inequality