155 research outputs found
Influence of relaxation on propagation, storage and retrieving of light pulses in electromagnetically induced transparency medium
By solving the self-consistent system of Maxwell and density matrix equations
to the first order with respect to nonadiabaticity, we obtain an analytical
solution for the probe pulse propagation. The conditions for efficient storage
of light are analyzed. The necessary conditions for optical propagation
distance has been obtained.Comment: 7 pages, 7 figure
On details of the thermodynamical derivation of the Ginsburg--Landau equations
We examine the procedure of thermodynamical derivation of the
Ginsburg--Landau equation for current, which is given unclear and contradictory
interpretations in existing textbooks. We clarify all steps of this procedure
and find as a consequence a limitation on the validity range of the
thermodynamic Ginsburg--Landau theory, which does not seem to be explicitely
stated up to now: we conclude that the thermodynamic theory is applicable only
to a superconducting specimen that is not a part of an external
current-carrying loop.Comment: 11 pages. Accepted for publication in 'Superconductor Science and
Technology
Dynamics of gas bubble growth in a supersaturated solution with Sievert's solubility law
This paper presents a theoretical description of diffusion growth of a gas
bubble after its nucleation in supersaturated liquid solution. We study systems
where gas molecules completely dissociate in the solvent into two parts, thus
making Sievert's solubility law valid. We show that the difference between
Henry's and Sievert's laws for chemical equilibrium conditions causes the
difference in bubble growth dynamics. Assuming that diffusion flux is steady we
obtain a differential equation on bubble radius. Bubble dynamics equation is
solved analytically for the case of homogeneous nucleation of a bubble, which
takes place at a significant pressure drop. We also obtain conditions of
diffusion flux steadiness. The fulfillment of these conditions is studied for
the case of nucleation of water vapor bubbles in magmatic melts.Comment: 22 pages, 3 figure
EVALUATION OF PRESCRIBING PATTERN OF FIXED DOSE COMBINATIONS OF ANTIHYPERTENSIVES AND ANTIDIABETIC AGENTS
  Objective: The objective of this research was to evaluate prescribing pattern of fixed dose combinations (FDCs) of antihypertensives and antidiabetic agents among patients of private hospitals.Methods: An observational study was carried out in the outpatient department of two hospitals. Data of patients being diagnosed with the symptoms of hypertension and diabetes were enrolled which mainly included information related to prescribe FDCs, i.e., antihypertensives and antidiabetics, respectively. Descriptive analysis of collected information was done which involved representation of demographical data, number of comorbidities, number of FDCs prescribed, and type of FDCs consequently.Results: Combination drug therapy was prescribed in maximum patients, which was enumerated as 93% among hypertensive patients and about 91% in diabetics. Average age of patients suffering more from hypertension was 64.5±18 years and that in case of diabetes sufferers was 54.5±18 years. The most frequent combination prescribed in hypertensive patients was of angiotensin receptor blocker (ARB) and calcium channel blocker (CCB) which were about 53%, and in diabetic patients, it was of biguanides and sulfonylureas about 63%. Comorbidity too was notified, and its estimation was 61% in hypertensive patients and 72% in diabetic patients, respectively.Conclusion: The study here demonstrates that the most often prescribed antihypertensive combination is of ARB and CCB, and subsequently for diabetes, the oral hypoglycemic combination is of biguanides and sulfonylureas. Most of FDCs contained medications of these two classes. Positive results were also observed in levels of blood pressure and glucose within the normal range
A super-Ohmic energy absorption in driven quantum chaotic systems
We consider energy absorption by driven chaotic systems of the symplectic
symmetry class. According to our analytical perturbative calculation, at the
initial stage of evolution the energy growth with time can be faster than
linear. This appears to be an analog of weak anti-localization in disordered
systems with spin-orbit interaction. Our analytical result is also confirmed by
numerical calculations for the symplectic quantum kicked rotor.Comment: 4 pages, 2 figure
Switchable collective pinning of flux quanta using magnetic vortex arrays
We constructed a superconducting/ferromagnetic hybrid system in which the
ordering of the pinning potential landscape for flux quanta can be manipulated.
Flux pinning is induced by an array of magnetic nanodots in the magnetic vortex
state, and controlled by the magnetic history. This allows switching on and off
the collective pinning of the flux-lattice. In addition, we observed
field-induced superconductivity that originates from the annihilation of flux
quanta induced by the stray fields from the magnetic vortices.Comment: PDF file 18 pages including 5 figures, accepted for publication in
Phys. Rev.
Modeling the organization of the WUSCHEL expression domain in the shoot apical meristem
Motivation: The above-ground tissues of higher plants are generated from a small region of cells situated at the plant apex called the shoot apical meristem. An important genetic control circuit modulating the size of the Arabidopsis thaliana meristem is a feed-back network between the CLAVATA3 and WUSCHEL genes. Although the expression patterns for these genes do not overlap, WUSCHEL activity is both necessary and sufficient (when expressed ectopically) for the induction of CLAVATA3 expression. However, upregulation of CLAVATA3 in conjunction with the receptor kinase CLAVATA1 results in the downregulation of WUSCHEL. Despite much work, experimental data for this network are incomplete and additional hypotheses are needed to explain the spatial locations and dynamics of these expression domains. Predictive mathematical models describing the system should provide a useful tool for investigating and discriminating among possible hypotheses, by determining which hypotheses best explain observed gene expression dynamics. Results: We are developing a method using in vivo live confocal microscopy to capture quantitative gene expression data and create templates for computational models. We present two models accounting for the organization of the WUSCHEL expression domain. Our preferred model uses a reaction-diffusion mechanism in which an activator induces WUSCHEL expression. This model is able to organize the WUSCHEL expression domain. In addition, the model predicts the dynamical reorganization seen in experiments where cells, including the WUSCHEL domain, are ablated, and it also predicts the spatial expansion of the WUSCHEL domain resulting from removal of the CLAVATA3 signal
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