77 research outputs found
Variations of cosmic rays according to the data of interplanetary probes Zond-3 and Venus-2
Cosmic ray intensity variation measured by Zond 3 and Venus 2 interplanetary probe
Quiet time fluxes and radial gradients of low-energy protons in the inner and outer heliosphere
Radial variations of low-energy (~1-8 MeV) quiet-time fluxes of protons are examined at distances of 20-85 AU during low solar activity periods using Voyager 1-2 data and compared with Ulysses fluxes at 1-5 AU as well as IMP-8 and SOHO at Earth and Helios between 0.3 and 1 AU. To obtain nearly background-free fluxes, the data are based on a careful pulse-height analysis. Except for high solar activity periods, contaminated with solar particles, all fluxes are very low, of the order of, and below 10^(-5) /(cm^2 s sr MeV). The Ulysses fluxes seem to be the lowest, whereas Helios and Voyager fluxes are nearly at the same level. The radial variation in 1-8 MeV suggests a negative gradient from 0.5 to about 2 AU that gradually turns
positive beyond 2 AU. Whereas the true variation is difficult to infer between 5 and 17 AU due to solar
contribution, from 30 to about 60 AU it exhibits a wide plateau, beyond which a slight increasing tendency is observed. At energies above ~6 MeV a clear contribution of anomalous hydrogen is observed
Enhancement of piezoelectricity in a mixed ferroelectric
We use first-principles density-functional total energy and polarization
calculations to calculate the piezoelectric tensor at zero temperature for both
cubic and simple tetragonal ordered supercells of Pb_3GeTe_4. The largest
piezoelectric coefficient for the tetragonal configuration is enhanced by a
factor of about three with respect to that of the cubic configuration. This can
be attributed to both the larger strain-induced motion of cations relative to
anions and higher Born effective charges in the tetragonal case. A normal mode
decomposition shows that both cation ordering and local relaxation weaken the
ferroelectric instability, enhancing piezoelectricity.Comment: 5 pages, revtex, 2 eps figure
LONG LASTING ENERGETIC PARTICLE INJECTION FROM A WEAK FLARE
ABSTRACT A relatively weak solar cosmic ray event registered at the Earth orbit following the flare of December 17, 1976 is discussed. The ma.in feature of the event is the existence of a prolonged unusually high proton and electron anisotropy; even at the end of the decay phase of the flare the motion of the particles were mainly directed away from the Sun.The durations of proton and electron anisotropies were different If prolonged particle injection is neglected the value of the anisotropy considerable exceeds all diffusive estimates. Time-intensity and anisotropy profiles of electrons and protons are fitted by a diffusive model including prolonged particle injection at the Sun The best agreement with the data is obtained if the duration of injection equals about 20 and 7 hours for protons and electrons, respectively
Influence of the space charge of an ion beam on the time-of-flight diagnostics of its composition
Measurement of the branching fraction of at KEDR
We present the study of the decay . The results
are based on of 5.2 million events collected by the KEDR detector at
VEPP-4M collider. The branching fraction is measured to be
where the first uncertainty is statistical, the second one
is systematic. This is the most precise single measurement of this quantity at
the moment
Investigations of Structural-Functional Aspects of Epizootic Process in Natural Plague Foci in Siberia
Comprehensively studied have been structural elements of ecosystems of Siberian natural plague foci, as well as levels of integration among epizootic process components, and ways of their functional interaction. Application of the complex approach to the surveillance over structural-functional elements of the parasitic system along with investigations of epizootic process dynamics has provided for identification of peculiarities as regards epizootics development, transformation and evolution of population and carrier/vector coenosis structure in time and space. Revealed is the genetic diversity of plague microbe circulating within the bounds of separate foci and zones of focality. Determined is a long-lasting anti-epidemic effect (more than 20 years) of the field desinsection in the Saglinsk meso-focus of the Tuva natural plague focus
Ожирение и метаболические нарушения у больных хронической обструктивной болезнью легких: возможности фенотипирования
The aim of the study was to compare clinical and functional features and healthrelated quality of life (HRQoL) in patients with chronic obstructive pulmonary disease (COPD) regarding to comorbid obesity as a phenotypic sign. Methods. Patient classification was performed using Kmeans clustering analysis (MacQueen). It resulted in the classification of subjects into four clinical groups with marked differences in COPD symptoms.Results. Subjects with obesity had severe airflow limitation and dyspnoea, frequent exacerbations, severely impaired HRQoL, poor survival, decreased physical activity, insulin resistance and increased systemic inflammation.Conclusion. Thus, COPD with comorbid obesity could be considered as a distinct phenotype of COPD with severe symptoms.Целью исследования явилось изучение клиникофункциональных параметров и качества жизни (КЖ) больных хронической обструктивной болезнью легких (ХОБЛ) c сопутствующим ожирением и метаболическими нарушениями с оценкой возможности их фенотипирования. На основании кластерного анализа, проведенного по методу kсредних МакКуина, выделены 4 группы пациентов с отличительными особенностями течения ХОБЛ. Установлено, что наличие сопутствующего ожирения у больных ХОБЛ ассоциировано со значительным снижением легочной функции, переносимости физической нагрузки, показателей КЖ и выживаемости, частыми обострениями, развитием инсулинорезистентности и активацией системных воспалительных реакций. Предполагается, что клинический вариант ХОБЛ с сопутствующим ожирением целесообразно рассматривать в качестве отдельного фенотипа заболевания, характеризующегося тяжелым течением
Ab Initio Study of the Structural Phase Transition in Cubic Pb_3GeTe_4
In the substitutionally disordered narrow-gap semiconductor Pb_{1-x}Ge_xTe, a
finite-temperature cubic-rhombohedral transition appears above a critical
concentration . As a first step towards a first-principles
investigation of this transition in the disordered system, a (hypothetical)
ordered cubic Pb_3GeTe_4 supercell is studied. First principles
density-functional calculations of total energies and linear response functions
are performed using the conjugate-gradients method with ab initio
pseudopotentials and a plane-wave basis set. Unstable modes in Pb_3GeTe_4 are
found, dominated by off-centering of the Ge ions coupled with displacements of
their neighboring Te ions. A model Hamiltonian for this system is constructed
using the lattice Wannier function formalism. The parameters for this
Hamiltonian are determined from first principles. The equilibrium
thermodynamics of the model system is studied via Metropolis Monte Carlo
simulations. The calculated transition temperature, T_c, is approximately 620K
for the cubic Pb_3GeTe_4 model, compared to the experimental value of T_c
\approx 350K for disordered Pb_{0.75}Ge_{0.25}Te. Generalization of this
analysis to the disordered Pb_{1-x}Ge_xTe system is discussed.Comment: 38 pages, LaTeX, 11 PostScript figure
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Energetic particle influence on the Earth's atmosphere
This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally
galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere
are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere
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