38 research outputs found

    Motion of a Vector Particle in a Curved Spacetime. II First Order Correction to a Geodesic in a Schwarzschild Background

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    The influence of spin on a photon's motion in a Schwarzschild and FRW spacetimes is studied. The first order correction to the geodesic motion is found. It is shown that unlike the world-lines of spinless particles, the photons world-lines do not lie in a plane.Comment: 14 pages, LaTeX2e, second paper in the series (the first one: gr-qc/0110067), replaced with typos and style corrected version, accepted in MPL

    The most general axially symmetric electrovac spacetime adimitting separable equations of motion

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    We obtain the most general solution of the Einstein electro - vacuum equation for the stationary axially symmetric spacetime in which the Hamilton-Jacobi and Klein - Gordon equations are separable. The most remarkable feature of the solution is its invariance under the duality transformation involving mass and NUT parameter, and the radial and angle coordinates. It is the general solution for a rotating (gravitational dyon) particle which is endowed with both gravoelectric and gravomagnetic charges, and there exists a duality transformation from one to the other. It also happens to be a transform of the Kerr - NUT solution. Like the Kerr family, it is also possible to make this solution radiating which asymptotically conforms to the Vaidya null radiation.Comment: 9 pages, RevTex, Accepted by Class. Quantum Grav. Title, Abstract and some expressions have been modified, typos corrected. The solution and main result remain unaltere

    Detailed study of the astrophysical direct capture reaction 6Li(p,γ)7Be^{6}{\rm Li}(p, \gamma)^{7}{\rm Be} in a potential model approach

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    The astrophysical SS factor and reaction rates of the direct capture process 6^{6}Li(p,γ)7\gamma)^{7}Be are estimated within a two-body single-channel potential model approach. Central potentials of the Gaussian-form in the 2P3/2^2P_{3/2} and 2P1/2^2P_{1/2} waves are adjusted to reproduce the binding energies and the empirical values of the asymptotic normalization coefficients (ANC) for the 7^7Be(3/2−^-) ground and 7^7Be(1/2−^-) excited bound states, respectively. The parameters of the potential in the most important 2S1/2^2S_{1/2} scattering channel were fitted to reproduce the empirical phase shifts from the literature and the low-energy astrophysical SS factor of the LUNA collaboration. The obtained results for the astrophysical SS factor and the reaction rates are in a very good agreement with available experimental data sets. The numerical estimates reproduce not only the absolute values, but also the energy and temperature dependence of the SS factor and reaction rates of the LUNA collaboration, respectively. The estimated 7Li/H^{7}{\rm Li/H} primordial abundance ratio (4.67±0.04)×10−10(4.67\pm 0.04 )\times 10^{-10} is well consistent with recent BBN result of (4.72±0.72)×10−10(4.72\pm 0.72) \times 10^{-10} after the Planck observation.Comment: 18 pages, 7 figure

    Agronomical Field Testing of New Kinds of Multicomponent Mineral Fertilizers

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    Analysis of modern scientific literature and patents has shown the absence of acid-free production technology of a mechanically activated multicomponent mineral fertilizer containing water-holding substances. Experimental researches connecting with mechanochemical activation and physicochemical properties of Karatau phosphorites prove a possibility of development of a new multicomponent mineral fertilizer. Application of inorganic and organic activators considerably improves qualities of fertilizers because the developed fertilizer mixtures contain nitrogen, phosphorus, potassium, humate and microelements. The suggested technology intends to use wastes of coal mining that leads to presence of humates and microelements in the end product. It was determined, that content of total nitrogen, phosphorus and potassium depends on a form of nitrogen-phosphorus-potassium-containing substances. The given article contains data of researches connecting with use of multicomponent mineral fertilizers in field conditions for cotton cultivation on irrigated light sierozems consisting of soil-forming rocks of loess and loess-type clay loams. The research results show the increase of soil’s fertility and cotton’s productivity. Studying of agronomic efficiency of the new kinds of mechanically activated multicomponent mineral fertilizers at the cultivation of a bean-cereal mixture has been carried out in the Negorelsk experimental nursery-garden of the Belarus State Technical University on a sod-podzol sandy-loam soil and has shown the essential influence on productivity and quality of the bean-cereal mixture. The researches fulfilled on a sod-podzol sandy-loam soil have revealed the essential increase of key indicators of feed productivity. Application of the mineral fertilizers has promoted increase of nitrogen, phosphorus and potassium content in green plants. In so doing content of calcium and magnesium in green mass depends from quantity of the fertilizer used to a smaller extent. An essential difference of crop capacity and feed productivity indicators depending on forms of the applied mineral fertilizers has not been found

    Pooling/bootstrap-based GWAS (pbGWAS) identifies new loci modifying the age of onset in PSEN1 p.Glu280Ala Alzheimer\u27s disease

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    The literature on GWAS (genome-wide association studies) data suggests that very large sample sizes (for example, 50,000 cases and 50,000 controls) may be required to detect significant associations of genomic regions for complex disorders such as Alzheimer\u27s disease (AD). Because of the challenges of obtaining such large cohorts, we describe here a novel sequential strategy that combines pooling of DNA and bootstrapping (pbGWAS) in order to significantly increase the statistical power and exponentially reduce expenses. We applied this method to a very homogeneous sample of patients belonging to a unique and clinically well-characterized multigenerational pedigree with one of the most severe forms of early onset AD, carrying the PSEN1 p.Glu280Ala mutation (often referred to as E280A mutation), which originated as a consequence of a founder effect. In this cohort, we identified novel loci genome-wide significantly associated as modifiers of the age of onset of AD (CD44, rs187116, P=1.29 _ 10?12; NPHP1, rs10173717, P=1.74 _ 10?12; CADPS2, rs3757536, P=1.54 _ 10?10; GREM2, rs12129547, P=1.69 _ 10?13, among others) as well as other loci known to be associated with AD. Regions identified by pbGWAS were confirmed by subsequent individual genotyping. The pbGWAS methodology and the genes it targeted could provide important insights in determining the genetic causes of AD and other complex conditions
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