135 research outputs found
Variable range cotunneling and conductivity of a granular metal
The Efros-Shklovskii law for the conductivity of granular metals is
interpreted as a result of a variable range cotunneling process. The
cotunneling between distant resonant grains is predominantly elastic at low T
<< T_c, while it is inelastic (i.e., accompanied by creation of electron-hole
pairs on a string of intermediate non-resonant grains) at T > T_c. The
corresponding E-S temperature T_ES in the latter case is slightly
(logarithmically) T-dependent. The magnetoresistance in the two cases is
different: it may be relatively strong and negative at T much below T_c, while
at T>T_c it is suppressed due to inelastic processes which destroy the
interference.Comment: Submitted to JETP Letter
The combined action of binase and bleomycin on human lung adenocarcinoma cells
© 2016, Pleiades Publishing, Ltd.Some microbial ribonucleases (RNases) demonstrate selective cytotoxic effect against a wide range of tumor cells. In this context combined use of cytotoxic RNases in complex therapy with other chemotherapeutic agents appears to be especially promising. In this study we have investigated the apoptosisinduced effect of Bacillus pumilus RNase (binase) in combination with known antitumor antibiotic bleomycin on human lung adenocarcinoma A549 cells. The combined effect of high concentrations of these agents did not have any mutual increase in their apoptosisinduced action, while a combination of nonapoptotic concentrations resulted in the increase of proportion of apoptotic cells up to 22% as compared with individual effect of bleomycin (6%) and binase (12%) used separately. These results indicate that binase and bleomycin are effective in combination of their low concentrations and ineffective in combination of their high concentrations
QCD and electromagnetic effects in polarization asymmetry of deep inelastic lepton-nucleon scattering under EMS experiment conditions
The results of experiment carried out by EMC in CERN are discussed,
as regards the influence of radiative effects on the observable parameter -
spin asymmetry
Negative hopping magnetoresistance of two-dimensional electron gas in a smooth random potential
We show that the tunnel coupling between semiclassical states localized in
different minima of a smooth random potential increases when magnetic field is
applied. This increase originates from the difference in gauge factors which
electron wave functions belonging to different electron ``lakes'' acquire in
the presence of the field. We illustrate the increase of coupling by a model
calculation of tunneling through a saddle point separating two adjacent lakes.
In the common case, when the barrier between two lakes is much narrower than
their size, the characteristic magnetic field is determined by the area of the
lakes, and thus may be quite small. The effect of the field on coupling
constants leads to a negative magnetoresistance in low-temperature conduction.Comment: 9 pages RevTe
Magnetoconductivity of Hubbard bands induced in Silicon MOSFETs
Sodium impurities are diffused electrically to the oxide-semiconductor
interface of a silicon MOSFET to create an impurity band. At low temperature
and at low electron density, the band is split into an upper and a lower
sections under the influence of Coulomb interactions. We used
magnetoconductivity measurements to provide evidence for the existence of
Hubbard bands and determine the nature of the states in each band.Comment: In press in Physica
Digitalization of the Educational Environment: Risk Assessment of Distance Education by Russian and Vietnamese Students
The digitalization of higher education is a long-term trend that gained a new impetus for further development because of the forced transition to distance learning during the COVID-19 pandemic. The aim of the article is to analyze the impact of digital transformation on the educational process in universities and to describe the risks through the students’ eyes. The analysis is based on the results of a survey conducted by the authors in 2020 among students of two universities - Moscow State Institute of International Relations (MGIMO) and the Institute of the Trade Union Movement of the General Confederation of Labor of Vietnam (IPLV).The article describes the methodology of the online survey. The attitude towards distance learning is interpreted as a three-level attitude with emotional, cognitive and behavioral aspects. It is suggested that students’ readiness to switch to distance learning is determined by a set of macro and micro factors. Among the macro factors are the national specifics of the educational system, traditions in the field of higher education, infrastructure, the national educational policy, and the mobilization potential of the population. Among the micro factors are the cognitive and other psychological characteristics of the students, the socio-psychological openness to innovation.According to the survey results, there is certain similarity in the way Russian and Vietnamese students assess their experience of distance learning. At the same time, significant differences in the perception of the outcome of the digital transformation of education have been revealed. For MGIMO students, major risks are associated with dehumanization, the severing of social ties, and the possible loss of student status. For Vietnamese students the most significant risks are mainly associated with the fears of the decreasing quality of education. It is therefore concluded that distance learning is both the field of opportunities and possible source of individual and institutional risks
Influence of Trichoderma asperellum metabolites on tissue regeneration against pyrene
We studied the influence of the culture fluid of fungi of the genus Trichoderma on Swiss Webster CFW mice after exposure to pyrene - polycyclic aromatic hydrocarbons, which can cause pathological changes in the body. Beneficial effect of Trichoderma metabolites on haematological parameters, the functioning of liver and nephros was shown, the trend toward regeneration of the structure of skin and liver after the damages, caused by the introduction of pyrene, was identified
Population of isomers in decay of the giant dipole resonance
The value of an isomeric ratio (IR) in N=81 isotones (Ba, Ce,
Nd and Sm) is studied by means of the ( reaction.
This quantity measures a probability to populate the isomeric state in respect
to the ground state population. In ( reactions, the giant dipole
resonance (GDR) is excited and after its decay by a neutron emission, the
nucleus has an excitation energy of a few MeV. The forthcoming decay
by direct or cascade transitions deexcites the nucleus into an isomeric or
ground state. It has been observed experimentally that the IR for Ba
and Ce equals about 0.13 while in two heavier isotones it is even less
than half the size. To explain this effect, the structure of the excited states
in the energy region up to 6.5 MeV has been calculated within the Quasiparticle
Phonon Model. Many states are found connected to the ground and isomeric states
by , and transitions. The single-particle component of the wave
function is responsible for the large values of the transitions. The calculated
value of the isomeric ratio is in very good agreement with the experimental
data for all isotones. A slightly different value of maximum energy with which
the nuclei rest after neutron decay of the GDR is responsible for the reported
effect of the A-dependence of the IR.Comment: 16 pages, 4 Fig
Why do adult women in Vietnam take iron tablets?
BACKGROUND: Conducting iron supplementation programs has been a major strategy to reduce iron deficiency anemia in pregnancy. However, only a few countries have reported improvements in the anemia rate at a national level. The strategies used for control of nutrition problems need regular review to maintain and improve their effectiveness. The objective of this study was to analyze the factors in compliance with taking iron tablets, where daily doses of iron (60 mg) and folic acid (400 μg) were distributed in rural Vietnamese communes. METHODS: A cross sectional survey was conducted in Nghe An province, Vietnam in January, 2003. The study population was adult women aged less than 35 years who delivered babies between August 1(st )2001 and December 1(st )2002 (n = 205), of which 159 took part in the study. Data for the study were collected from a series of workshops with community leaders, focus group discussions with community members and a questionnaire survey. RESULTS: Improvements in the rate of anemia was not given a high priority as one of the commune's needs, but the participants still made efforts to continue taking iron tablets. Two major factors motivated the participants to continue taking iron tablets; their experience of fewer spells of dizziness (50%), and their concern for the health of their newborn baby (54%). When examining the reasons for taking iron tablets for at least 5–9 months, the most important factor was identified as 'a frequent supply of iron tablets' (OR = 11.93, 95% CI: 4.33–32.85). CONCLUSION: The study found that multiple poor environmental risk factors discouraged women from taking iron tablets continuously. The availability (frequent supply) of iron tablets was the most effective way to help adult women to continue taking iron tablets
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