Variational separable expansion scheme for two-body Coulomb-scattering problems

We present a separable expansion approximation method for Coulomb-like potentials which is based on Schwinger variational principle and uses Coulomb-Sturmian functions as basis states. The new scheme provides faster convergence with respect to our formerly used non-variational approach.Comment: some typos correcte

Jets and produced particles in pp collisions from SPS to RHIC energies for nuclear applications

Higher-order pQCD corrections play an important role in the reproduction of data at high transverse momenta in the energy range 20 GeV $\leq \sqrt{s} \leq 200$ GeV. Recent calculations of photon and pion production in $pp$ collisions yield detailed information on the next-to-leading order contributions. However, the application of these results in proton-nucleus and nucleus-nucleus collisions is not straightforward. The study of nuclear effects requires a simplified understanding of the output of these computations. Here we summarize our analysis of recent calculations, aimed at handling the NLO results by introducing process and energy-dependent $K$ factors.Comment: 4 pages with 5 eps figures include

Continued fraction representation of the Coulomb Green's operator and unified description of bound, resonant and scattering states

If a quantum mechanical Hamiltonian has an infinite symmetric tridiagonal (Jacobi) matrix form in some discrete Hilbert-space basis representation, then its Green's operator can be constructed in terms of a continued fraction. As an illustrative example we discuss the Coulomb Green's operator in Coulomb-Sturmian basis representation. Based on this representation, a quantum mechanical approximation method for solving Lippmann-Schwinger integral equations can be established, which is equally applicable for bound-, resonant- and scattering-state problems with free and Coulombic asymptotics as well. The performance of this technique is illustrated with a detailed investigation of a nuclear potential describing the interaction of two $\alpha$ particles.Comment: 7 pages, 4 ps figures, revised versio

Exploring Self-Determination and Recreational Sports Participation for Adolescents with Disabilities

Self-determination is a vital skill for individuals with disabilities and provides significant benefits, such as more positive adult outcomes and greater quality of life. Recreational sports participation is another fundamental aspect of life for individuals with disabilities, as it leads to increased physical activity, enhanced self-esteem, and improved peer acceptance. Despite the well-researched benefits of both self-determination skills and recreational sports participation, a literature review revealed few studies that examined the relationship between self-determination and recreational sports participation for individuals, particularly adolescents, with disabilities. This mixed methods study was designed to fill this void, using questionnaires, interviews, and observations to explore the intersection of self-determination and recreational sports participation for adolescents with disabilities. The results of the study suggested that students and parents had not considered self-determination in conjunction with recreational sports. Categories and themes derived from qualitative analyses supported the quantitative analyses indicating that three rounds of self-determination coaching and feedback combined with action plans improved student self-determination. The results provide significant implications for coaches, parents, and teachers to promote and support self-determination within recreational sports environments. Future research should continue to explore ways to support the development of self-determined activities and abilities for individuals with disabilities within recreational sports, enhancing the generalizability of the present study and expanding the findings to provide models for infusing self-determined learning opportunities within recreational sports for adolescents with disabilities

Effective Q-Q Interactions in Constituent Quark Models

We study the performance of some recent potential models suggested as effective interactions between constituent quarks. In particular, we address constituent quark models for baryons with hybrid Q-Q interactions stemming from one-gluon plus meson exchanges. Upon recalculating two of such models we find them to fail in describing the N and \Delta spectra. Our calculations are based on accurate solutions of the three-quark systems in both a variational Schr\"odinger and a rigorous Faddeev approach. It is argued that hybrid {Q-Q} interactions encounter difficulties in describing baryon spectra due to the specific contributions from one-gluon and pion exchanges together. In contrast, a chiral constituent quark model with a Q-Q interaction solely derived from Goldstone-boson exchange is capable of providing a unified description of both the N and \Delta spectra in good agreement with phenomenology.Comment: 21 pages, LaTe

Three-potential formalism for the three-body scattering problem with attractive Coulomb interactions

A three-body scattering process in the presence of Coulomb interaction can be decomposed formally into a two-body single channel, a two-body multichannel and a genuine three-body scattering. The corresponding integral equations are coupled Lippmann-Schwinger and Faddeev-Merkuriev integral equations. We solve them by applying the Coulomb-Sturmian separable expansion method. We present elastic scattering and reaction cross sections of the $e^++H$ system both below and above the $H(n=2)$ threshold. We found excellent agreements with previous calculations in most cases.Comment: 12 pages, 3 figure

A PNJL model in 0+1 Dimensions

We formulate the Polyakov-Nambu-Jona-Lasinio (PNJL) model in 0+1 dimensions. The thermodynamics captured by the partition function yields a bulk pressure, as well as quark susceptibilities versus temperature that are similar to the ones in 3+1 dimensions. Around the transition temperature the behavior in the pressure and quark susceptibilities follows from the interplay between the lowest Matsubara frequency and the Polyakov line. The reduction to the lowest Matsubara frequency yields a matrix Model. In the presence of the Polyakov line the UV part of the Dirac spectrum features oscillations when close to the transition temperature.Comment: 18 pages, 13 figure

Parthenogenetic capability of three species in Poa pratensis L. aggregation

Parthenogenesis, as an asexual reproductive method gives rise to a new prospect in agricultural production: the opportunity to establish genetically stable, seed-propagating clones of crops, which can perpetuate themselves across countless sporophytic generations. Apomictic processes of Poa pratensis has been extensively discussed by several studies. We studied the parthenogenesis capability of species in Poa pratensis L. aggregation collected from seminatural habitats by auxin-test. The article presents that this asexual mode of reproduction occurs in two other species of the Poa pratensis group, in Poa angustifolia and Poa humilis too. The results add more information to the reproductive behavior of these Poa species and could be useful in plant breeding

Reducing systematic errors in time-frequency resolved mode number analysis

The present paper describes the effect of magnetic pick-up coil transfer functions on mode number analysis in magnetically confined fusion plasmas. Magnetic probes mounted inside the vacuum chamber are widely used to characterize the mode structure of magnetohydrodynamic modes, as, due to their relative simplicity and compact nature, several coils can be distributed over the vessel. Phase differences between the transfer functions of different magnetic pick-up coils lead to systematic errors in time- and frequency resolved mode number analysis. This paper presents the first in-situ, end-to-end calibration of a magnetic pick-up coil system which was carried out by using an in-vessel driving coil on ASDEX Upgrade. The effect of the phase differences in the pick-up coil transfer functions is most significant in the 50-250 kHz frequency range, where the relative phase shift between the different probes can be up to 1 radian (~60{\deg}). By applying a correction based on the transfer functions we found smaller residuals of mode number fitting in the considered discharges. In most cases an order of magnitude improvement was observed in the residuals of the mode number fits, which could open the way to investigate weaker electromagnetic oscillations with even high mode numbers

Disseminated eruptive giant mollusca contagiosa in an adult psoriasis patient during efalizumab therapy

Molluscum contagiosum is a common viral skin infection in children with atopic diathesis and not rare in HIV patients. We report a 45-year-old psoriasis patient who developed eruptive mollusca contagiosa during an antipsoriatic treatment with efalizumab. Copyright (C) 2008 S. Karger AG, Basel