2,587 research outputs found

    Commenting on the 'great debate' : general abilities, specific abilities, and the tools of the trade

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    We review papers in the special issue regarding the great debate on general and specific abilities. Papers in the special issue either provided an empirical examination of the debate using a uniform dataset or they provided a debate commentary. Themes that run through the papers and that are discussed further here are that: (1) the importance of general and specific ability predictors will largely depend on the outcome to be predicted, (2) the effectiveness of both general and specific predictors will largely depend on the quality and breadth of how the manifest indicators are measured, and (3) research on general and specific ability predictors is alive and well and more research is warranted. We conclude by providing a review of potentially fruitful areas of future research

    Conditions of the Development of Logistic Centers in Poland in the Context of European States Experiences

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    The article is, for the most part, the aftermath of his own examinations carried out in years 2007-2010 and concerning logistic centers development conditioning.Artykuł jest w znacznej mierze pokłosiem badań własnych autora przeprowadzonych w latach: 2007-2010 dotyczących uwarunkowań rozwoju centrów logistycznych

    Toward high-precision values of the self energy of non-S states in hydrogen and hydrogen-like ions

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    The method and status of a study to provide numerical, high-precision values of the self-energy level shift in hydrogen and hydrogen-like ions is described. Graphs of the self energy in hydrogen-like ions with nuclear charge number between 20 and 110 are given for a large number of states. The self-energy is the largest contribution of Quantum Electrodynamics (QED) to the energy levels of these atomic systems. These results greatly expand the number of levels for which the self energy is known with a controlled and high precision. Applications include the adjustment of the Rydberg constant and atomic calculations that take into account QED effects.Comment: Minor changes since previous versio

    Recoil correction to the bound-electron g factor in H-like atoms to all orders in αZ\alpha Z

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    The nuclear recoil correction to the bound-electron g factor in H-like atoms is calculated to first order in m/Mm/M and to all orders in αZ\alpha Z. The calculation is performed in the range Z=1-100. A large contribution of terms of order (αZ)5(\alpha Z)^5 and higher is found. Even for hydrogen, the higher-order correction exceeds the (αZ)4(\alpha Z)^4 term, while for uranium it is above the leading (αZ)2(\alpha Z)^2 correction.Comment: 6 pages, 3 tables, 1 figur

    Evidence for the absence of regularization corrections to the partial-wave renormalization procedure in one-loop self energy calculations in external fields

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    The equivalence of the covariant renormalization and the partial-wave renormaliz ation (PWR) approach is proven explicitly for the one-loop self-energy correction (SE) of a bound electron state in the presence of external perturbation potentials. No spurious correctio n terms to the noncovariant PWR scheme are generated for Coulomb-type screening potentia ls and for external magnetic fields. It is shown that in numerical calculations of the SE with Coulombic perturbation potential spurious terms result from an improper treatment of the unphysical high-energy contribution. A method for performing the PWR utilizing the relativistic B-spline approach for the construction of the Dirac spectrum in external magnetic fields is proposed. This method is applied for calculating QED corrections to the bound-electron gg-factor in H-like ions. Within the level of accuracy of about 0.1% no spurious terms are generated in numerical calculations of the SE in magnetic fields.Comment: 22 pages, LaTeX, 1 figur

    Calculated Electron Fluxes at Airplane Altitudes

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    A precision measurement of atmospheric electron fluxes has been performed on a Japanese commercial airliner (Enomoto, {\it et al.}, 1991). We have performed a monte carlo calculation of the cosmic ray secondary electron fluxes expected in this experiment. The monte carlo uses the hadronic portion of our neutrino flux cascade program combined with the electromagnetic cascade portion of the CERN library program GEANT. Our results give good agreement with the data, provided we boost the overall normalization of the primary cosmic ray flux by 12\% over the normalization used in the neutrino flux calculation.Comment: in REVTEX, 12 pages + 4 figures available upon reques

    Finite nuclear size and Lamb shift of p-wave atomic states

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    We consider corrections to the Lamb shift of p-wave atomic states due to the finite nuclear size (FNS). In other words, these are radiative corrections to the atomic isotop shift related to FNS. It is shown that the structure of the corrections is qualitatively different from that for s-wave states. The perturbation theory expansion for the relative correction for a p1/2p_{1/2}-state starts from αln(1/Zα)\alpha\ln(1/Z\alpha)-term, while for s1/2s_{1/2}-states it starts from Zα2Z\alpha^2 term. Here α\alpha is the fine structure constant and ZZ is the nuclear charge. In the present work we calculate the α\alpha-terms for 2p2p-states, the result for 2p1/22p_{1/2}-state reads (8α/9π)[ln(1/(Zα)2)+0.710](8\alpha/9\pi)[\ln(1/(Z\alpha)^2)+0.710]. Even more interesting are p3/2p_{3/2}-states. In this case the ``correction'' is by several orders of magnitude larger than the ``leading'' FNS shift.Comment: 4 pages, 2 figure

    Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia

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    Citation: Barhoumi, W., Fares, W., Cherni, S., Derbali, M., Dachraoui, K., Chelbi, I., . . . Zhioua, E. (2016). Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia. International Journal of Environmental Research and Public Health, 13(3), 10. doi:10.3390/ijerph13030329The current spread of zoonotic visceral leishmaniasis (ZVL) throughout arid areas of Central Tunisia is a major public health concern. The main objective of this study is to investigate whether the development of irrigation in arid bio-geographical areas in Central Tunisia have led to the establishment of a stable cycle involving sand flies of the subgenus Larroussius and Leishmania infantum, and subsequently to the emergence of ZVL. Sand flies were collected from the village of Saddaguia, a highly irrigated zone located within an arid bio-geographical area of Central Tunisia by using modified Centers for Diseases Control (CDC) light traps. Morphological keys were used to identify sand flies. Collected sand flies were pooled with up to 30 specimens per pool according to date and tested by nested Polymerase Chain Reaction (PCR) DNA sequencing from positive pools was used to identify Leishmania spp. A total of 4915 sand flies (2422 females and 2493 males) were collected from Saddaguia in September and in October 2014. Morphological identification confirmed sand flies of the subgenus Larroussius to be predominant. PCR analysis followed by DNA sequencing indicated that 15 pools were infected with L. infantum yielding an overall infection rate of 0.6%. The majority of the infected pools were of sand fly species belonging to subgenus Larroussius. Intense irrigation applied to the arid bio-geographical areas in Central Tunisia is at the origin of the development of an environment capable of sustaining important populations of sand flies of the subgenus Larroussius. This has led to the establishment of stable transmission cycles of L. infantum and subsequently to the emergence of ZVL

    Soft Contributions to Hard Pion Photoproduction

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    Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where perturbatively calculable processes dominate. Our soft process estimate is based on vector meson dominance and data based parameterizations of semiexclusive hadronic cross sections. We find that soft processes dominate in single pion photoproduction somewhat past 2 GeV transverse momentum at a few times 10 GeV incoming energy. The recent polarization asymmetry data is consistent with the perturbative asymmetry being diluted by polarization insensitive soft processes. Determining the polarized gluon distribution using hard pion photoproduction appears feasible with a few hundred GeV incoming energy (in the target rest frame).Comment: 6 pages, 5 figure

    Charged Scalar Particles and τ\tau Leptonic Decay

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    Charged scalar particles introduced in some extensions of the standard model can induce τ\tau leptonic decay at tree level. We find that with some charged SU(2)-singlet scalar particles, like ones introduced in Zee-type models, τ\tau leptonic decay width is always smaller than what is predicted by the standard model, therefore they may offer a natural solution to τ\tau decay puzzle. To be more specific, we examine some Zee-type models in detail to see if at the same time they are acceptable in particle physics, cosmology and astrophysics. It is shown that τ\tau decay data do put some constrains on these models.Comment: ICTP Report No. IC/93/31, 12 pages, Latex, one figure is not included, it is available upon deman
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