Low-|t| structures in elastic scattering at the LHC

Possible low-$|t|$ structures in the differential cross section of $pp$ elastic scattering at the LHC are predicted. It is argued that the change of the slope of the elastic cross section near $t=-0.1$ GeV$^2$ has the same origin as that observed in 1972 at the ISR, both related to the $4m_{\pi}^2$ branch point in the $|t|$-channel of the scattering amplitude. Apart from that structure, tiny oscillations at small $|t|$ may be present on the cone at low $|t|$.Comment: 13 pages, 4 Tables; to be published in Acta Physica Polonica

Scalar perturbations in cosmological models with quark nuggets

In this paper we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Supposing that a small fraction of colored objects escaped hadronization and survived up to now in the form of quark-gluon nuggets (QNs), and also taking into account radiation, we investigate scalar perturbations of the FRW metrics due to inhomogeneities of dustlike matter as well as fluctuations of QNs and radiation. In particular, we demonstrate that the nonrelativistic gravitational potential is defined by the distribution of inhomogeneities/fluctuations of both dustlike matter and QNs. Consequently, QNs can be distributed around the baryonic inhomogeneities (e.g., galaxies) in such a way that it can solve the problem of the flatness of the rotation curves. We also show that the fluctuations of radiation are caused by both the inhomogeneities in the form of galaxies and the fluctuations of quark-gluon nuggets. Therefore, if QNs exist, the CMB anisotropy should contain also the contributions from QNs. Additionally, the spatial distribution of the radiation fluctuations is defined by the gravitational potential. All these results look physically reasonable.Comment: 7 pages, no figures. arXiv admin note: text overlap with arXiv:1301.041

Predictive Value of ADHD Symptomatology on Motives and Outcomes of Stimulant Misuse

ADHD stimulant misuse is defined as taking a stimulant used to treat ADHD either without having a prescription for that stimulant or in a manner that deviates from the prescription’s instructions. This has been a growing trend among undergraduate students over recent years. Prior research has found that misusers are likely to have severe symptoms of ADHD, misuse for primarily academic reasons, and display problems associated with substance abuse. The current study aimed to determine the predictive value of ADHD symptomatology on frequency of ADHD stimulant misuse, mediated by academic motives for misuse and substance abuse problems. The survey for this study was completed by 1,082 students at a state university in southeastern Virginia. Data from 184 misusers were analyzed using SEM path analysis. A significant direct effect was found with ADHD symptomatology on frequency of misuse, and this effect was mediated by academic motives for misuse, but not by substance abuse problems. The results suggest that undergraduate students with undiagnosed problems with attention and hyperactivity might have academic difficulties for which they would turn to ADHD stimulant misuse as a solution. While not analyzed in this study, such a student, who may already be using other substances for non-academic reasons, could later develop medical, social, and family problems associated with substance abuse

Eastern Policy of the EU: the Visegrad Countries' Perspective. OSW Point of View, February 2003

1. After its enlargement, scheduled for 2004, the European Union will face a completely new situation at its eastern borders. This new situation calls for a new concept of the EU eastern activities, i.e. for development of the new Eastern Policy of the EU. 2. Due to a number of specific features such as geographical location, closeness of ties, direct risk factors etc., the Visegrad countries will and should be particularly interested in the process of formulating the new EU Eastern Policy. Consequently, they should be the co-makers of this policy. 3. The new EU Eastern Policy should differ fundamentally from the Union's traditional eastern relations. Firstly, its scope should not cover the entire CIS area: instead, the policy should focus on some of the European successor states of the former Soviet Union, namely Belarus, Russia and Ukraine, as well as Moldova, following the accession of Romania. It does not seem advisable to exclude the Russian Federation from this policy and to develop and implement a separate policy towards it. The new Eastern Policy should be an autonomous component and one of the most important elements in the overall foreign policy of the EU. 4. Secondly, the new Eastern Policy should be founded on the following two pillars: a region-oriented strategy, which could be called the Eastern Dimension, and reshaped strategies for individual countries. The Eastern Dimension should set up a universal framework of co-operation, defining its basic mechanisms and objectives. These should include: the adaptation assistance programme, JHA, transborder co-operation, social dialogue and transport infrastructures. The approach, however, should be kept flexible, taking into account the specific situation of each country. This purpose should be served by keeping in place the existing bilateral institutional contacts between the EU and each of its eastern neighbours, and by developing a national strategy for each neighbour

Temporal structure in spiking patterns of ganglion cells defines perceptual thresholds in rodents with subretinal prosthesis.

Subretinal prostheses are designed to restore sight in patients blinded by retinal degeneration using electrical stimulation of the inner retinal neurons. To relate retinal output to perception, we studied behavioral thresholds in blind rats with photovoltaic subretinal prostheses stimulated by full-field pulsed illumination at 20 Hz, and measured retinal ganglion cell (RGC) responses to similar stimuli ex-vivo. Behaviorally, rats exhibited startling response to changes in brightness, with an average contrast threshold of 12%, which could not be explained by changes in the average RGC spiking rate. However, RGCs exhibited millisecond-scale variations in spike timing, even when the average rate did not change significantly. At 12% temporal contrast, changes in firing patterns of prosthetic response were as significant as with 2.3% contrast steps in visible light stimulation of healthy retinas. This suggests that millisecond-scale changes in spiking patterns define perceptual thresholds of prosthetic vision. Response to the last pulse in the stimulation burst lasted longer than the steady-state response during the burst. This may be interpreted as an excitatory OFF response to prosthetic stimulation, and can explain behavioral response to decrease in illumination. Contrast enhancement of images prior to delivery to subretinal prosthesis can partially compensate for reduced contrast sensitivity of prosthetic vision

FFCA: a feasibility-based method for flux coupling analysis of metabolic networks

<p>Abstract</p> <p>Background</p> <p>Flux coupling analysis (FCA) is a useful method for finding dependencies between fluxes of a metabolic network at steady-state. FCA classifies reactions into subsets (called coupled reaction sets) in which activity of one reaction implies activity of another reaction. Several approaches for FCA have been proposed in the literature.</p> <p>Results</p> <p>We introduce a new FCA algorithm, FFCA (Feasibility-based Flux Coupling Analysis), which is based on checking the feasibility of a system of linear inequalities. We show on a set of benchmarks that for genome-scale networks FFCA is faster than other existing FCA methods.</p> <p>Conclusions</p> <p>We present FFCA as a new method for flux coupling analysis and prove it to be faster than existing approaches. A corresponding software tool is freely available for non-commercial use at <url>http://www.bioinformatics.org/ffca/</url>.</p