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.

Investigation of pulse shape neutron-gamma discrimination

The role of neutron beam investigation is significant not only for fundamental science but also for various fields of applied science. This work is dedicated to the formation of neutron beams using the external 18-MeV proton beam of IBA cyclotron C18/18 with a beam current of up to 100 µA. The facility is located at the A. Alikhanyan National Science Laboratory (Yerevan Physics Institute). The possibility to obtain thermal or epithermal neutron beams using the external proton beam of the cyclotron is studied using Geant4 simulations. In this case, a quasimonoenergetic neutron source 9Be (p, n)9B reaction is chosen. As a result of the simulations, the optimal thickness of the 9Be beryllium isotope target is determined. The induced neutron beam is accompanied by a gamma ray background. To decrease the number of accompanying gamma rays, the lead absorber is considered. As a method of separating neutrons from gamma rays, the pulse shape discrimination (PSD) technique is developed. This study shows the possibility of neutron-gamma PSD and its applicability using the EJ-299-33A plastic scintillator

An analysis of blood pressure screening of 21 112 participants in Armenia: May Measurement Month 2018.

Elevated blood pressure (BP) is a growing burden worldwide and is the leading cause of mortality and disability-adjusted life years all over the world. May Measurement Month (MMM) is a global initiative aimed to raise 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 to July 2018. Blood pressure measurement, the definition of hypertension (HTN) and statistical analysis followed the standard MMM protocol. The study was conducted in public areas (17 sites in Yerevan and 22 in regions), both indoor and outdoor, as well as in 78 primary care centres. A total of 21 112 individuals were screened during MMM18, of which 20 732 had three BP measurements available. The mean age of screened individuals was 46.2 ± 17.3 years, 57.8% were female. At the time of screening, 26.1% were on antihypertensive medication. After imputation, the percentage of participants with HTN was 38.7%, and 76.7% of them were aware of their high BP. Of participants receiving treatment, 47.1% had a controlled BP. MMM18 was the largest BP screening campaign undertaken in Armenia. We found that the proportion of HTN is substantial in Armenia, which may be a vital contributor to the growing burden of non-communicable diseases. Our results also suggest that untreated HTN is common and when treated still not adequately controlled in Armenia. The current situation, with an insufficient control rate of HTN, must be changed as soon as possible

On the energy-momentum tensor for a scalar field on manifolds with boundaries

We argue that already at classical level the energy-momentum tensor for a scalar field on manifolds with boundaries in addition to the bulk part contains a contribution located on the boundary. Using the standard variational procedure for the action with the boundary term, the expression for the surface energy-momentum tensor is derived for arbitrary bulk and boundary geometries. Integral conservation laws are investigated. The corresponding conserved charges are constructed and their relation to the proper densities is discussed. Further we study the vacuum expectation value of the energy-momentum tensor in the corresponding quantum field theory. It is shown that the surface term in the energy-momentum tensor is essential to obtain the equality between the vacuum energy, evaluated as the sum of the zero-point energies for each normal mode of frequency, and the energy derived by the integration of the corresponding vacuum energy density. As an application, by using the zeta function technique, we evaluate the surface energy for a quantum scalar field confined inside a spherical shell.Comment: 25 pages, 2 figures, section and appendix on the surface energy for a spherical shell are added, references added, accepted for publication in Phys. Rev.

Self-determined citizens? New forms of civic activism and citizenship in Armenia

This article examines the recent emergence and growth of grassroots social movements in Armenia which are locally known as ‘civic initiatives’. It considers what their emergence tells us about the development of civil society and the changing understandings and practices of citizenship in Armenia in the post-Soviet period. It analyses why civic initiatives explicitly reject and distance themselves from formal, professionalised NGOs and what new models of civic activism and citizenship they have introduced. It argues that civic initiatives embrace a more political understanding of civil society than that which was introduced by Western donors in the 1990s