175 research outputs found
Spatial variability and seasonal dynamics of dissolved organic matter in surface and soil pore waters in mire-forest landscapes in the Komi Republic, Northwest-Russia
Proton-potassium exchange during fermentation of glucose and glycerol by Escherichia coli hydrogenase mutant at alkaline and acidic pH
Wightman function and Casimir densities for Robin plates in the Fulling-Rindler vacuum
Wightman function, the vacuum expectation values of the field square and the
energy-momentum tensor are investigated for a massive scalar field with an
arbitrary curvature coupling parameter in the region between two infinite
parallel plates moving by uniform proper acceleration. We assume that the field
is prepared in the Fulling-Rindler vacuum state and satisfies Robin boundary
conditions on the plates. The mode-summation method is used with a combination
of a variant of the generalized Abel-Plana formula. This allows to extract
manifestly the contributions to the expectation values due to a single boundary
and to present the second plate-induced parts in terms of exponentially
convergent integrals. Various limiting cases are investigated. The vacuum
forces acting on the boundaries are presented as a sum of the self-action and
'interaction' terms. The first one contains well known surface divergences and
needs a further renormalization. The 'interaction' forces between the plates
are investigated as functions of the proper accelerations and coefficients in
the boundary conditions. We show that there is a region in the space of these
parameters in which the 'interaction' forces are repulsive for small distances
and attractive for large distances.Comment: 20 pages, 2 figures, discussion added, accepted for publication in
Int. J. Mod. Phys.
Integrated pest management of major pests and diseases in eastern Europe and the Caucasus
This book promotes Integrated Pest Management, to contribute to reduced reliance on pesticides and the avoidance of adverse impacts from pesticide use on the health and safety of farming communities, consumers and the environment. Through the IPM approach, technical advice is provided to help plan methods and measures to control major pests and diseases occurring or expected to occur in the countries of Western Asia and Eastern Europe. The specific descriptions contain a short summary of the biology of the species, completed with information on methods and tools of monitoring and control. Preventive control methods are also discussed
Cosmological evolution with negative energy densities
For general number of spatial dimensions we investigate the cosmological
dynamics driven by a cosmological constant and by a source with barotropic
equation of state. It is assumed that for both those sources the energy density
can be either positive or negative. Exact solutions of the cosmological
equations are provided for flat models. For models with curved space and with
zero cosmological constant the general solutions are expressed in terms of the
hypergeometric function. The qualitative evolution is described for all values
of the equation of state parameter. We specify the values of that parameter and
the combinations of the signs for the cosmological constant and matter energy
density for which the cosmological dynamics is nonsingular. An example is
considered with positive cosmological constant and negative matter energy
density induced by the polarization of the hyperbolic vacuum.Comment: 12 pages, 3 figures. Discussion and references added, accepted for
publication in Astrophysic
Vacuum Quantum Effects for Parallel Plates Moving by Uniform Acceleration in Static de Sitter Space
The Casimir forces on two parallel plates moving by uniform proper
acceleration in static de Sitter background due to conformally coupled massless
scalar field satisfying Dirichlet boundary conditions on the plates is
investigated. Static de Sitter space is conformally related to the Rindler
space, as a result we can obtain vacuum expectation values of energy-momentum
tensor for conformally invariant field in static de Sitter space from the
corresponding Rindler counterpart by the conformal transformation.Comment: 10 pages, no figures, accepted for publication in Int. J. Mod. Phys.
May Measurement Month 2017: an analysis of blood pressure screening results in Armenia-Europe
Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative aimed at raising awareness of high BP and to act as a temporary solution to the lack of screening programmes worldwide. An opportunistic cross-sectional survey of volunteers aged ≥18 was carried out in May 2017. Blood pressure measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. The study was conducted in public areas (14 sites in Yerevan and 18 in regions), both indoor and outdoor, as well as in 42 primary care centres. A total of 9199 individuals were screened during MMM17 of which 9186 had three BP measurements available. The mean age of screened individuals was 50 ± 16.7 years, 57.3% was female. At the time of screening 17.9% were on antihypertensive medication. After imputation, a percentage of participants with hypertension was 33.9%, and 52.9% of them were on treatment. Of those treated, 77.0% had uncontrolled BP. MMM17 was the largest BP screening campaign undertaken in Armenia. We found that in Armenia, untreated hypertension is common, as is not adequately treated hypertension
Casimir energy in the Fulling--Rindler vacuum
The Casimir energy is evaluated for massless scalar fields under Dirichlet or
Neumann boundary conditions, and for the electromagnetic field with perfect
conductor boundary conditions on one and two infinite parallel plates moving by
uniform proper acceleration through the Fulling--Rindler vacuum in an arbitrary
number of spacetime dimension. For the geometry of a single plate the both
regions of the right Rindler wedge, (i) on the right (RR region) and (ii) on
the left (RL region) of the plate are considered. The zeta function technique
is used, in combination with contour integral representations. The Casimir
energies for separate RR and RL regions contain pole and finite contributions.
For an infinitely thin plate taking RR and RL regions together, in odd spatial
dimensions the pole parts cancel and the Casimir energy for the whole Rindler
wedge is finite. In spatial dimensions the total Casimir energy for a
single plate is negative for Dirichlet scalar and positive for Neumann scalar
and the electromagnetic field. The total Casimir energy for two plates geometry
is presented in the form of a sum of the Casimir energies for separate plates
plus an additional interference term. The latter is negative for all values of
the plates separation for both Dirichlet and Neumann scalars, and for the
electromagnetic field.Comment: 28 pages, 4 figures, references added, typos corrected, accepted for
publication in Phys. Rev.
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