57 research outputs found

    Universal behavior of quantum Green's functions

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    We consider a general one-particle Hamiltonian H = - \Delta_r + u(r) defined in a d-dimensional domain. The object of interest is the time-independent Green function G_z(r,r') = . Recently, in one dimension (1D), the Green's function problem was solved explicitly in inverse form, with diagonal elements of Green's function as prescribed variables. The first aim of this paper is to extract from the 1D inverse solution such information about Green's function which cannot be deduced directly from its definition. Among others, this information involves universal, i.e. u(r)-independent, behavior of Green's function close to the domain boundary. The second aim is to extend the inverse formalism to higher dimensions, especially to 3D, and to derive the universal form of Green's function for various shapes of the confining domain boundary.Comment: 46 pages, the shortened version submitted to J. Math. Phy

    InGaAs n-MOS devices integrated using ALD-HfO2/metal gate without surface cleaning and interfacial layer passivation

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    [[abstract]]In this paper, there is no surface cleaning and interfacial passivation layer prior to the ALD-HfO2. However, the oxide/InGaAs interface is atomically sharp without the existence of arsenic oxides, strongly indicating self-cleaning of the ALD process. Excellent well-behaved J-EG and C-V characteristics of ALD-HfO2/In0.53Ga0.47As/InP have been demonstrated in this work.[[fileno]]2010113010135[[department]]物理

    Menopausal symptoms assessment among middle age women in Kushtia, Bangladesh

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    <p>Abstract</p> <p>Background</p> <p>There are few menopausal study data available in South East Asia especially in Bangladesh. This study was conducted in a well populated town named Kushtia, which is located in the western part of Bangladesh.</p> <p>Objectives</p> <p>This study was aimed to document the menopausal-related symptoms among middle age women of Kushtia region of Bangladesh.</p> <p>Methods</p> <p>By using modified MRS (Menopause Rating Scale) questionnaire, 509 women aged 40-70 years were interviewed to document symptoms commonly associated with menopause.</p> <p>Findings</p> <p>The mean age of menopause was 51.14 years. The most prevalent symptoms reported include, feeling tired (92.90%); headache (88.80%); joint and muscular discomfort (76.20%); physical and mental exhaustion (60.90%) and sleeplessness (54.40%) which are followed by depressive mood (37.30%); irritability (36%); dryness of vagina (36%); hot flushes and sweating (35.80%); anxiety (34.20%). However, noted less frequent symptoms were sexual problem (31.20%); cardiac discomfort (19.10%) and bladder problem (12.80%).</p> <p>Conclusions</p> <p>The prevalence of menopausal symptoms found in this study correspond to other studies on Asian women however the prevalence of classical menopausal symptoms of hot flushes and sweating were lower compared to studies on Caucasian women.</p

    Students’ satisfaction and teaching efficiency of university offer

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    This study analyses the factors affecting students’ satisfaction with university experience, focusing on the aspects characterising the teaching efficiency of educational offer. For this purpose, organisation of teaching activities, available information, teaching materials, and other facilities offered to students to make their learning experience more successful, are considered as indicators of teaching efficiency. Our interest in this topic is justified by the importance that students’ satisfaction assumes, not only as indicator of the quality of educational services but also for its relationship with overall life satisfaction and subjective well-being. A structural equation model with latent variables is estimated by using survey and administrative data of the University of Pisa. Main findings seem to show that teaching efficiency has a positive effect on satisfaction and suggest that whenever it is inadequate, or at least, considered as such, students are less satisfied for their university experience. The effects of other factors on students’ satisfaction such as studies organisation, social capital and internship experience are also discussed

    Study of e+eppˉe^+e^- \rightarrow p\bar{p} in the vicinity of ψ(3770)\psi(3770)

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    Using 2917 pb1\rm{pb}^{-1} of data accumulated at 3.773~GeV\rm{GeV}, 44.5~pb1\rm{pb}^{-1} of data accumulated at 3.65~GeV\rm{GeV} and data accumulated during a ψ(3770)\psi(3770) line-shape scan with the BESIII detector, the reaction e+eppˉe^+e^-\rightarrow p\bar{p} is studied considering a possible interference between resonant and continuum amplitudes. The cross section of e+eψ(3770)ppˉe^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}, σ(e+eψ(3770)ppˉ)\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}), is found to have two solutions, determined to be (0.059±0.032±0.0120.059\pm0.032\pm0.012) pb with the phase angle ϕ=(255.8±37.9±4.8)\phi = (255.8\pm37.9\pm4.8)^\circ (<<0.11 pb at the 90% confidence level), or σ(e+eψ(3770)ppˉ)=(2.57±0.12±0.12\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12) pb with ϕ=(266.9±6.1±0.9)\phi = (266.9\pm6.1\pm0.9)^\circ both of which agree with a destructive interference. Using the obtained cross section of ψ(3770)ppˉ\psi(3770)\rightarrow p\bar{p}, the cross section of ppˉψ(3770)p\bar{p}\rightarrow \psi(3770), which is useful information for the future PANDA experiment, is estimated to be either (9.8±5.79.8\pm5.7) nb (<17.2<17.2 nb at 90% C.L.) or (425.6±42.9)(425.6\pm42.9) nb

    Rapid identification of soil cadmium pollution risk at regional scale based on visible and near-infrared spectroscopy

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    Soil heavy metal pollution due to long-term sewage irrigation is a serious environmental problem in many irrigation areas in northern China. Quickly identifying its pollution status is an important basis for remediation. Visible-near-infrared reflectance spectroscopy (VNIRS) provides a useful tool. In a case study, 76 soil samples were collected and their reflectance spectra were used to estimate cadmium (Cd) concentration by partial least squares regression (PLSR) and back propagation neural network (BPNN). To reduce noise, six pre-treatments were compared, in which orthogonal signal correction (OSC) was first used in soil Cd estimation. Spectral analysis and geostatistics were combined to identify Cd pollution hotspots. Results showed that Cd was accumulated in topsoil at the study area. OSC can effectively remove irrelevant information to improve prediction accuracy. More accurate estimation was achieved by applying a BPNN. Soil Cd pollution hotspots could be identified by interpolating the predicted values obtained from spectral estimates. Keywords Soil cadmium; Visible and near-infrared spectroscopy; Orthogonal signal correction; Back propagation neural network; Indicator krigin

    Field resistance of transgenic plantain to nematodes has potential for future African food security.

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    Plant parasitic nematodes impose losses of up to 70% on plantains and cooking bananas in Africa. Application of nematicides is inappropriate and resistant cultivars are unavailable. Where grown, demand for plantain is more than for other staple crops. Confined field testing demonstrated that transgenic expression of a biosafe, anti-feedant cysteine proteinase inhibitor and an anti-root invasion, non-lethal synthetic peptide confers resistance to plantain against the key nematode pests Radopholus similis and Helicotylenchus multicinctus. The best peptide transgenic line showed improved agronomic performance relative to non-transgenic controls and provided about 99% nematode resistance at harvest of the mother crop. Its yield was about 186% in comparison with the nematode challenged control non-transgenic plants based on larger bunches and diminished plant toppling in storms, due to less root damage. This is strong evidence for utilizing this resistance to support the future food security of 70 million, mainly poor Africans that depend upon plantain as a staple food
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