300 research outputs found
Analytical Evaluation of the MoM Matrix Elements
Cataloged from PDF version of article.Derivation of the closed-form Green’s functions has
eliminated the computationally expensive evaluation of the Sommerfeld
integrals to obtain the Green’s functions in the spatial
domain. Therefore, using the closed-form Green’s functions in
conjunction with the method of moments (MOM) has improved
the computational efficiency of the technique significantly. Further
improvement can he achieved on the calculation of the
matrix elements involved in the MOM, usually double integrals for
planar geometries, by eliminating the numerical integration. The
contribution of this paper is to present the analytical evaluation
of the matrix elements when the closed-form Green’s functions
are used, and to demonstrate the amount of improvement in
computation time
Small-Energy Analysis for the Selfadjoint Matrix Schroedinger Operator on the Half Line
The matrix Schroedinger equation with a selfadjoint matrix potential is
considered on the half line with the most general selfadjoint boundary
condition at the origin. When the matrix potential is integrable and has a
first moment, it is shown that the corresponding scattering matrix is
continuous at zero energy. An explicit formula is provided for the scattering
matrix at zero energy. The small-energy asymptotics are established also for
the corresponding Jost matrix, its inverse, and various other quantities
relevant to the corresponding direct and inverse scattering problems.Comment: This published version has been edited to improve the presentation of
the result
A unified approach to Darboux transformations
We analyze a certain class of integral equations related to Marchenko
equations and Gel'fand-Levitan equations associated with various systems of
ordinary differential operators. When the integral operator is perturbed by a
finite-rank perturbation, we explicitly evaluate the change in the solution. We
show how this result provides a unified approach to Darboux transformations
associated with various systems of ordinary differential operators. We
illustrate our theory by deriving the Darboux transformation for the
Zakharov-Shabat system and show how the potential and wave function change when
a discrete eigenvalue is added to the spectrum.Comment: final version that will appear in Inverse Problem
Exact solutions to the focusing nonlinear Schrodinger equation
A method is given to construct globally analytic (in space and time) exact
solutions to the focusing cubic nonlinear Schrodinger equation on the line. An
explicit formula and its equivalents are presented to express such exact
solutions in a compact form in terms of matrix exponentials. Such exact
solutions can alternatively be written explicitly as algebraic combinations of
exponential, trigonometric, and polynomial functions of the spatial and
temporal coordinates.Comment: 60 pages, 18 figure
Vagal nerve stimulation started just prior to reperfusion limits infarct size and no-reflow
Vagal nerve stimulation (VNS) started prior to, or during, ischemia has been shown to reduce infarct size. Here, we investigated the effect of VNS when started just prior to, and continued during early, reperfusion on infarct size and no-reflow and studied the underlying mechanisms. For this purpose, swine (13 VNS, 10 sham) underwent 45 min mid-LAD occlusion followed by 120 min of reperfusion. VNS was started 5 min prior to reperfusion and continued until 15 min of reperfusion. Area at risk, area of no-reflow (% of infarct area) and infarct size (% of area at risk), circulating cytokines, and regional myocardial leukocyte influx were assessed after 120 min of reperfusion. VNS significantly reduced infarct size from 67 ± 2 % in sham to 54 ± 5 % and area of no-reflow from 54 ± 6 % in sham to 32 ± 6 %. These effects were accompanied by reductions in neutrophil (~40 %) and macrophage (~60 %) infiltration in the infarct area (all p < 0.05), whereas systemic circulating plasma levels of TNFα and IL6 were not affected. The degree of cardioprotection could not be explained by the VNS-induced bradycardia or the VNS-induced decrease in the double product of heart rate and left ventricular systolic pressure. In the presence of NO-synthase inhibitor LNNA, VNS no longer attenuated infarct size and area of no-reflow, which was paralleled by similarly unaffected regional leukocyte infiltration. In conclusion, VNS is a promising novel adjunctive therapy that limits reperfusion injury in a large animal model of acute myocardial infarction
Inverse Spectral-Scattering Problem with Two Sets of Discrete Spectra for the Radial Schroedinger Equation
The Schroedinger equation on the half line is considered with a real-valued,
integrable potential having a finite first moment. It is shown that the
potential and the boundary conditions are uniquely determined by the data
containing the discrete eigenvalues for a boundary condition at the origin, the
continuous part of the spectral measure for that boundary condition, and a
subset of the discrete eigenvalues for a different boundary condition. This
result extends the celebrated two-spectrum uniqueness theorem of Borg and
Marchenko to the case where there is also a continuous spectru
Evaluation of ocular pulse amplitude in non-arteritic anterior ischaemic optic neuropathy
Correlates of loneliness among university students
Background The purpose of this study was to investigate level of loneliness, essential needs during university education, and relationships between loneliness, essential needs, and characteristics of university students. A sample comprising 721 students participated in the study. The mean age was 21.58 (SD = 1.73) with a range from 18 to 25. The majority of the students were female (70.6%) and were living in students' dormitory (67.5%) with low (87.8%) income, away from their parents. Methods The UCLA-R loneliness scale and sociodemographic questionnaire which includes an open-ended question on essential needs during university education were administered. Pearson-Product-Moment correlations were used to explore the relationships between participants' loneliness, needs, and characteristics. Results It was found that 60.2% of the participants experienced loneliness. Economical support (81.6%), social interaction (46.9%) and psychosocial support (35%) were the essential needs during university education reported by the participants. The study findings indicate that there were significant relationships between the needs of economical support, social interaction, and loneliness level of university students. Results also show that there were significant relationships among romantic relationship, parents' status and loneliness. Participants' loneliness levels were relatively higher who had not any romantic relationship and were not from married families. Conclusion The findings of this study provided essential information, about Turkish university students, concerning: level of loneliness and relationships that exist among loneliness, needs and sociodemographic characteristics. The findings also suggest implications for psychosocial practice. Because of the mean of loneliness were found to be high (45.49 ± 10.07), for this study, professionals need to pay attention to Turkish university students' psychosocial state, and need to empower them in establishing social relations
Window of opportunity to achieve major outcomes in early rheumatoid arthritis patients: how persistence with therapy matters
The histone methyltransferase SETD2 negatively regulates cell size
Cell size varies between cell types but is tightly regulated by cell intrinsic and extrinsic mechanisms. Cell size control is important for cell function, and changes in cell size are frequently observed in cancer. Here, we uncover a role for SETD2 in regulating cell size. SETD2 is a lysine methyltransferase and a tumor suppressor protein involved in transcription, RNA processing and DNA repair. At the molecular level, SETD2 is best known for associating with RNA polymerase II through its Set2-Rbp1 interacting (SRI) domain and methylating histone H3 on lysine 36 (H3K36) during transcription. Using multiple independent perturbation strategies, we identify SETD2 as a negative regulator of global protein synthesis rates and cell size. We provide evidence that overexpression of the H3K36 demethylase KDM4A or the oncohistone H3.3K36M also increase cell size. In addition, ectopic overexpression of a decoy SRI domain increased cell size, suggesting that the relevant substrate is engaged by SETD2 via its SRI domain. These data add a central role of SETD2 in regulating cellular physiology and warrant further studies on separating the different functions of SETD2 in cancer development
- …