38 research outputs found
Motion of a Vector Particle in a Curved Spacetime. II First Order Correction to a Geodesic in a Schwarzschild Background
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
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 in a potential model approach
The astrophysical factor and reaction rates of the direct capture process
Li(p,Be are estimated within a two-body single-channel
potential model approach. Central potentials of the Gaussian-form in the
and waves are adjusted to reproduce the binding
energies and the empirical values of the asymptotic normalization coefficients
(ANC) for the Be(3/2) ground and Be(1/2) excited bound states,
respectively. The parameters of the potential in the most important
scattering channel were fitted to reproduce the empirical phase shifts from the
literature and the low-energy astrophysical factor of the LUNA
collaboration. The obtained results for the astrophysical 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 factor and reaction rates of
the LUNA collaboration, respectively. The estimated primordial
abundance ratio is well consistent with recent
BBN result of after the Planck observation.Comment: 18 pages, 7 figure
Agronomical Field Testing of New Kinds of Multicomponent Mineral Fertilizers
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
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