Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for $^{54,55,56}$Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic \textit{state-by-state} calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, $^{54,55,56}$Fe, are considered to be key players in decreasing the electron-to-baryon ratio ($Y_{e}$) mainly via electron capture on these nuclide. The structure of the presupernova star is altered both by the changes in $Y_{e}$ and the entropy of the core material. Results are encouraging and are compared against measurements (where possible) and other calculations. The calculated electron capture rates are in overall good agreement with the shell model results. During the presupernova evolution of massive stars, from oxygen shell burning stages till around end of convective core silicon burning, the calculated electron capture rates on $^{54}$Fe are around three times bigger than the corresponding shell model rates. The calculated positron capture rates, however, are suppressed by two to five orders of magnitude.Comment: 18 pages, 12 figures, 10 table

Empirical Formulae Evaluation for Hydraulic Conductivity Determination Based on Grain Size Analysis

Seven empirical formulae to calculate hydraulic conductivity using grain size distribution of unconsolidated aquifer materials have been evaluated in this study. Four soil samples extracted from an injection or recharge well during borehole drilling aimed at recharging the ground water through rainwater harvesting in Lahore Pakistan. The sample testing and grading analysis were done in CEWRE, UET Lahore soil laboratory. Results showed that out of seven empirical formulae three formulae (Kozeny-Carman, Hazen and Breyer) reliably estimated hydraulic conductivities of the various soil samples well within the known ranges while the others four formulae Slitcher, Terzaghi, USBR, Alyamani & Sen methods underestimated the results as compared to constant head method results for all samples. Kozeny-Carman Equation proved to be the best estimator of most samples analyzed, and maybe, even for a wide range of other soil types. This best estimation is followed by Hazen and Breyer formula after Kozeny-Carman formula. Most importantly, all these empirical formulae are to be used strictly within their domains of applicability

Fine-Grid Calculations for Stellar Electron and Positron Capture Rates on Fe-Isotopes

The acquisition of precise and reliable nuclear data is a prerequisite to success for stellar evolution and nucleosynthesis studies. Core-collapse simulators find it challenging to generate an explosion from the collapse of the core of massive stars. It is believed that a better understanding of the microphysics of core-collapse can lead to successful results. The weak interaction processes are able to trigger the collapse and control the lepton-to-baryon ratio ($Y_{e}$) of the core material. It is suggested that the temporal variation of $Y_{e}$ within the core of a massive star has a pivotal role to play in the stellar evolution and a fine-tuning of this parameter at various stages of presupernova evolution is the key to generate an explosion. During the presupernova evolution of massive stars, isotopes of iron, mainly $^{54,55,56}$Fe, are considered to be key players in controlling $Y_{e}$ ratio via electron capture on these nuclide. Recently an improved microscopic calculation of weak interaction mediated rates for iron isotopes was introduced using the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic \textit{state-by-state} calculation of stellar capture rates which greatly increases the reliability of calculated rates. The results were suggestive of some fine-tuning of the $Y_{e}$ ratio during various phases of stellar evolution. Here we present for the first time the fine-grid calculation of the electron and positron capture rates on $^{54,55,56}$Fe. Core-collapse simulators may find this calculation suitable for interpolation purposes and for necessary incorporation in the stellar evolution codes.Comment: 21 pages, 6 ps figures and 2 table

Development of a Standalone Application to Measure Crosstalk in MMG Signals from Forearm Muscles during Wrist Postures

Mechanomyography (MMG) signals can be used to study and analyze skeletal muscles. It retains its potential application in various fields including athletics, sports, medicine and prosthetic control. MMG signals do exhibit crosstalk from adjacent muscles. The measurement of crosstalk in MMG signals could be beneficial for the study of muscle mechanics. Hence, this research contributes to the development of a standalone application (APP) to measure crosstalk in MMG signals coming from human forearm muscles during various wrist postures. The application has been developed on National Instruments LabVIEW software version 14.0. Peak cross correlations have been used as a measure of crosstalk between neighboring muscles. The results produced by APP while measuring crosstalk in MMG signals are very close to literature. Hence the results for APP have been validated by previous studies. The APP can be used for both forms of MMG data either stored in the form of tdms files or real-time signals. MMG signals are acquired, displayed, processed and finally used for measurement of crosstalk. All the steps are done automatically in the APP. Hence APP cannot only save time to measure crosstalk through other tedious methods but it also provides a source of MMG data validation in a real-time environment

Basic psychological needs and psychological well-being: the mediating role of Instagram addiction

Instagram is a popular social network platform that brings benefits to many. However, for a small minority, problematic use may be an issue of concern (i.e., Instagram addiction). This addiction appears to originate from various contexts and can also have psychosocial consequences. The present study investigated the basic psychological needs and psychological well-being and the mediating role of Instagram addiction. The sample comprised 660 participants who completed a number of psychometric scales including the: Instagram Addiction Scale (15 questions), Basic Psychological Needs Scale (21 questions), and Psychological Well-being Scale (18 questions). The results confirmed the fit of the model, and showed the direct adverse and significant effects of basic psychological needs on Instagram addiction, Instagram addiction on psychological well-being, and the positive and significant direct impact of basic needs on psychological well-being. There were also significant indirect effects of basic needs (autonomy, competence, and relatedness) in well-being via Instagram addiction. The failure to satisfy basic psychological needs appears to play an important role in the addictive use of Instagram, leading to a decrease in psychological well-being

Coulomb breakup of 6Li^6\rm{Li} into α + d\alpha\,+\,\rm{d} in the field of ion 208Pb^{208}\rm{Pb}

The triple differential cross section of $^{208}\rm{Pb}(^6\rm{Li};\alpha,\rm{d})^{208}\rm{Pb}$ elastic Coulomb breakup is calculated using the semiclassical method. We fit the parameters of the Woods-Saxon potential using the experimental $\alpha-\rm{d}$ phase shifts for different states to describe the relative motion of $\alpha$-particle and deuteron. In order to check the validity of the two particle approach for $\alpha-d$ system we apply a potential model to describe the $^2\rm{H}(\alpha,\gamma)^6\rm{Li}$ radiative capture. Our results for the Coulomb breakup of $^6\rm{Li}$ show large value of the forward-backward asymmetry of the $\alpha$-particle and deuteron emission around zero energy in the $^6\rm{Li}$ center-of-mass (c.m.) system. Comparison of the results of our calculation with experimental data gives evidence for the dominance of the Coulomb dissociation mechanism at the $\alpha-d$ relative energy larger than $E_{\alpha\,d}>300\,\rm{keV}$ and sufficiently big contribution of nuclear distortion at $E_{\alpha\,d}$ near zero energy, but essentially smaller than the value reported in Ref.[F. Hammache et al. Phys.Rev. C82, 065802 (2010)].Comment: 11 pages, 5 figures (one figure removed), added the results of new calculations and performed the audit of the tex

Biosynthesis of Mitochondrial Porin and Insertion into the Outer Mitochondrial Membrane of Neuruspora crassa

Mitochondrial porin, the major protein of the outer mitochondrial membrane is synthesized by free cytoplasmic polysomes. The apparent molecular weight of the porin synthesized in homologous or heterologous cell-free systems is the same as that of the mature porin. Transfer in vitro of mitochondrial porin from the cytosolic fraction into the outer membrane of mitochondria could be demonstrated. Before membrane insertion, mitochondrial porin is highly sensitive to added proteinase; afterwards it is strongly protected. Binding of the precursor form to mitochondria occurs at 4°C and appears to precede insertion into the membrane. Unlike transfer of many precursor proteins into or across the inner mitochondrial membrane, assembly of the porin is not dependent on an electrical potential across the inner membrane

Involvement of (pro)renin receptor in the glomerular filtration barrier

(Pro)renin receptor-bound prorenin not only causes the generation of angiotensin II via the nonproteolytic activation of prorenin, it also activates the receptor’s own intracellular signaling pathways independent of the generated angiotensin II. Within the kidneys, the (pro)renin receptor is not only present in the glomerular mesangium, it is also abundant in podocytes, which play an important role in the maintenance of the glomerular filtration barrier. Recent in vivo studies have demonstrated that the overexpression of the (pro)renin receptor to a degree similar to that observed in hypertensive rat kidneys leads to slowly progressive nephropathy with proteinuria. In addition, the handle region peptide, which acts as a decoy peptide and competitively inhibits the binding of prorenin to the receptor, is more beneficial than an angiotensin-converting enzyme inhibitor with regard to alleviating proteinuria and glomerulosclerosis in experimental animal models of diabetes and essential hypertension. Thus, the (pro)renin receptor may be upregulated in podocytes under hypertensive conditions and may contribute to the breakdown of the glomerular filtration barrier

The effect of curricular and extracurricular activities on university students? entrepreneurial intention and competences

This study examines how the alliance-building process affects the intention to enter into international alliances in the case of small and medium-sized enterprises (SMEs). From a psychological perspective (Perceived Behavioural Control), the authors analyse the alliance-building process as an inhibitor of the international collaboration intention, considering to what extent the experience affects the intention of the partners involved. The study explores these hypotheses based on a sample of 220 Spanish SMEs. The results provide empirical evidence showing that the intention to develop international alliances is negatively affected by the search and the selection process as well as by the negotiation of the agreement, which reduces the intention to establish an international agreement. In addition, the intention is moderated by the experience of the SME manager. Moreover, there is a negative relationship between the extent of the SME manager's international experience and the intention to develop an international alliance