11,207 research outputs found
Parasitic pumping currents in an interacting quantum dot
We analyze the charge and spin pumping in an interacting dot within the
almost adiabatic limit. By using a non-equilibrium Green's function technique
within the time-dependent slave boson approximation, we analyze the pumped
current in terms of the dynamical constraints in the infinite-U regime. The
results show the presence of parasitic pumping currents due to the additional
phases of the constraints. The behavior of the pumped current through the
quantum dot is illustrated in the spin-insensitive and in the spin-sensitive
case relevant for spintronics applications
Rancang Bangun Aplikasi Pelayanan dan Rekam Medis Calon Tenaga Kerja Indonesia pada AL-HUDA MEDICAL CENTER
Al-Huda Medical Center is special unit of Al-Huda hospital which manages check-up service for Prospective Indonesian Migrant Worker (CTKI). Al-Huda Medical Center wants to improve the service process and medical record of CTKI using computer system. There are five main problems found in the field regarding this matter, they include (1) all data reports consisting of registration to medical record database is still in paper-based documents, (2) the registration number is processed manually, (3) there is no barcode in health certificate, (4) specimen is labelled using handwriting (5) registration report, medical record, form, and film paper is done manually in terms of calculation and writing. The solution offered for the aforementioned problems is developing a web-based application which is able to manage service process, medical record, and report. Furthermore, this application provides health certificate which fulfills the standardization of the destination country of CTKI. This application also offers the more accurate reports compared to paper-based documentation
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The Risk of Cancer from CT Scans and Other Sources of Low-Dose Radiation: A Critical Appraisal of Methodologic Quality
AbstractIntroduction: Concern exists that radiation exposure from computerized tomography (CT) will cause thousands of malignancies. Other experts share the same perspective regarding the risk from additional sources of low-dose ionizing radiation, such as the releases from Three Mile Island (1979; Pennsylvania USA) and Fukushima (2011; Okuma, Fukushima Prefecture, Japan) nuclear power plant disasters. If this premise is false, the fear of cancer leading patients and physicians to avoid CT scans and disaster responders to initiate forcedevacuations is unfounded.Study Objective: This investigation provides a quantitative evaluation of the methodologic quality of studies to determine the evidentiary strength supporting or refuting a causal relationshipbetween low-dose radiation and cancer. It will assess the number of higher qualitystudies that support or question the role of low-dose radiation in oncogenesis.Methods: This investigation is a systematic, methodologic review of articles published from 1975–2017 examining cancer risk from external low-dose x-ray and gamma radiation, defined as less than 200 millisievert (mSv). Following the PRISMA guidelines, the authors performed a search of the PubMed, Cochrane, Scopus, and Web of Science databases. Methodologies of selected articles were scored using the Newcastle Ottawa Scale (NOS) and a tool identifying 11 lower quality indicators. Manuscript methodologies were rankedas higher quality if they scored no lower than seven out of nine on the NOS and contained no more than two lower quality indicators. Investigators then characterized articles as supporting or not supporting a causal relationship between low-dose radiation and cancer.Results: Investigators identified 4,382 articles for initial review. A total of 62 articles met all inclusion/exclusion criteria and were evaluated in this study. Quantitative evaluation of the manuscripts’ methodologic strengths found 25 studies met higher quality criteria while 37 studies met lower quality criteria. Of the 25 studies with higher quality methods, 21 out of 25did not support cancer induction by low-dose radiation (P = .0003).Conclusions: A clear preponderance of articles with higher quality methods found no increased risk of cancer from low-dose radiation. The evidence suggests that exposure to multiple CT scans and other sources of low-dose radiation with a cumulative dose up to 100 mSv (approximately 10 scans), and possibly as high as 200 mSv (approximately 20 scans), does not increase cancer risk
Low energy phases of bilayer Bi predicted by structure search in two dimensions
We employ an ab-initio structure search algorithm to explore the
configurational space of Bi in quasi two dimensions. A confinement potential
restricts the movement of atoms within a pre-defined thickness during structure
search calculations within the minima hopping method to find the stable and
metastable forms of bilayer Bi. In addition to recovering the two known
low-energy structures (puckered monoclinic and buckled hexagonal), our
calculations predict three new structures of bilayer Bi. We call these
structures the , , and phases of bilayer Bi, which are,
respectively, 63, 72, and 83 meV/atom higher in energy than that of the
monoclinic ground state, and thus potentially synthesizable using appropriate
substrates. We also compare the structural, electronic, and vibrational
properties of the different phases. The puckered monoclinic, buckled hexagonal,
and phases exhibit a semiconducting energy gap, whereas and
phases are metallic. We notice an unusual Mexican-hat type band
dispersion leading to a van Hove singularity in the buckled hexagonal bilayer
Bi. Notably, we find symmetry-protected topological Dirac points in the
electronic spectrum of the phase. The new structures suggest that
bilayer Bi provides a novel playground to study distortion-mediated
metal-insulator phase transitions
3D numerical analysis of the unsteady turbulent swirling flow in a conical diffuser using Fluent and OpenFOAM
The paper presents three-dimensional numerical investigations of the unsteady swirling flow in a conical diffuser with a precessing vortex rope. The helical vortex breakdown, also known as precessing vortex rope in the engineering literature, benefits from a large body of literature aimed either at elucidating the physics of the phenomenon and building mathematical models, or at developing and testing practical solutions to control the causes and/or the effects. In this paper we investigate the unsteady hydrodynamic fields with a well-known precessing vortex rope computed with the FLUENT and OpenFOAM CFD codes. The main goal is to elucidate the physics of the phenomenon. The three-dimensional computational domain corresponds to the test section of a test rig designed and developed at Politehnica University of Timisoara. The same domain and grid with two millions cells is considered in both codes. The boundary conditions and problem setup are presented for each case. The unsteady pressure fluctuations along to the element of the conical diffuser are recorded. The numerical pressure fluctuations are validated against experimental data measured on the wall of the test rig. Consequently, the fundamental frequency and higher harmonics of the vortex rope is determined by a Fourier analysis
3D numerical analysis of the unsteady turbulent swirling flow in a conical diffuser using Fluent and OpenFOAM
The paper presents three-dimensional numerical investigations of the unsteady swirling flow in a conical diffuser with a precessing vortex rope. The helical vortex breakdown, also known as precessing vortex rope in the engineering literature, benefits from a large body of literature aimed either at elucidating the physics of the phenomenon and building mathematical models, or at developing and testing practical solutions to control the causes and/or the effects. In this paper we investigate the unsteady hydrodynamic fields with a well-known precessing vortex rope computed with the FLUENT and OpenFOAM CFD codes. The main goal is to elucidate the physics of the phenomenon. The three-dimensional computational domain corresponds to the test section of a test rig designed and developed at Politehnica University of Timisoara. The same domain and grid with two millions cells is considered in both codes. The boundary conditions and problem setup are presented for each case. The unsteady pressure fluctuations along to the element of the conical diffuser are recorded. The numerical pressure fluctuations are validated against experimental data measured on the wall of the test rig. Consequently, the fundamental frequency and higher harmonics of the vortex rope is determined by a Fourier analysis
Reference Profile Correlation Reveals Estrogen-like Trancriptional Activity of Curcumin
Background: Several secondary metabolites from herbal nutrient products act as weak estrogens (phytoestrogens), competing with endogenous estrogen for binding to the estrogen receptors and inhibiting steroid converting enzymes. However, it is still unclear whether these compounds elicit estrogen dependent transcription of genes at physiological concentrations. Methods: We compare the effects of physiological concentrations (100 nM) of the two phytoestrogens Enterolactone and Quercetin and the suspected phytoestrogen Curcumin on gene expression in the breast cancer cell line MCF7 with the effects elicited by 17-beta-estradiol (E2). Results: All three phytocompounds have weak effects on gene transcription; most of the E2 genes respond to the phytoestrogens in the same direction though to a much lesser extent and in the order Curcumin > Quercetin > Enterolactone. Gene regulation induced by these compounds was low for genes strongly induced by E2 and similar to the latter for genes only weakly regulated by the classic estrogen. Of interest with regard to the treatment of menopausal symptoms, the survival factor Birc5/survivin and the oncogene MYBL1 are strongly induced by E2 but only marginally by phytoestrogens. Conclusion: This approach demonstrates estrogenic effects of putative phytoestrogens at physiological concentrations and shows, for the first time, estrogenic effects of Curcumin. Copyright (C) 2010 S. Karger AG, Base
Inclusion for Cultural Education in Museums, Audio and Touch Interaction
Inclusive access to culture for all people in institutions, such as museums, is an important issue specified in French laws and is also recognized internationally. This article investigates inclusion of blind and partially blind visitors in museums. The pilot study conducted involves blind, partially blind, and sighted people and observes their perception of audio descriptions and different tactile representations within a museum. 12 participants were asked to experience three different conditions for 3 scenes of the Bayeux Tapestry using inclusive and co-created audio descriptions, simplified swell paper representations, and high relief representations. Overall, a high level of interest was found across all conditions, with multimodality through audio and tactile stimulus found to have enriched participants’ experience. However, more guided tactile exploration would be better. From participants’ feedback, some observations have emerged which could be explored for the development of new technologies to better respond to museum visitors’ expectations
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