5,440 research outputs found

    Intersubband transitions in pseudomorphic InGaAs/GaAs/AlGaAs multiple step quantum wells

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    Intersubband transitions from the ground state to the first and second excited states in pseudomorphic AlGaAs/InGaAs/GaAs/AlGaAs multiple step quantum wells have been observed. The step well structure has a configuration of two AlGaAs barriers confining an InGaAs/GaAs step. Multiple step wells were grown on GaAs substrate with each InGaAs layer compressively strained. During the growth, a uniform growth condition was adopted so that inconvenient long growth interruptions and fast temperature ramps when switching the materials were eliminated. The sample was examined by cross‐sectional transmission electron microscopy, an x‐ray rocking curve technique, and the results show good crystal quality using this simple growth method. Theoretical calculations were performed to fit the intersubband absorption spectrum. The calculated energies are in good agreement with the observed peak positions for both the 1→2 and 1→3 transitions

    Pemahaman Manajemen Perusahaan Tentang Peraturan Perpajakan Dan Kepatuhan Wajib Pajak Badan (Studi Kasus Di Kota Metro)

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    This study aims to analyze how an understanding of the companys management and tax laws and how an understanding of the compliance management company corporate taxpayers in Metro City. From the analysis and discussion, it can be concluded that the understanding of the companys management at Metro City on tax laws and compliance with corporate taxpayers is good. This indicates that the company has to understand the obligations and rights as a taxpayer as stated in the taxation legislation.It may be advisable for the company is the management should further deepen the existing section of each item in the tax laws that apply today. As for the tax laws suggested policy makers should not make taxpayers feel difficulty in meeting its obligations as a taxpayer and where to make changes to the tax laws should be communicated to the taxpayer in order to avoid errors in the implementation and fulfillment of the rights of taxpayers

    Isgur - Wise Functions for Confined Light Quarks in a Colour Electric Potential

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    We explore the influence on the Isgur-Wise function of the colour electric potential between heavy and light quarks in mesons. It is shown that in bag models, its inclusion tends to restore light quark flavour symmetry relative to the MIT bag predictions, and that relative to this model it flattens the Isgur-Wise function. Results compare very well with observations.Comment: 9 pages, 1 figure (available upon request), Latex, TPJU - 4/9

    Pengaruh Komposisi Nano Semen Pada Perilaku Beton

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    This study aimed to investigate the influence of the composition nano-cement to compressive strength and flexural strength on concrete. First step in the produced of concrete with nano materials, necessary constituent concepts concrete material selection right. Cement with fine grains have a larger surface area than the coarse grained cement, thus increasing the surface area of a grain of cement hydration process faster so that more amount of cement that can react with water to increase so the compressive strength will be increase too. Increased in the compressive strength of concrete will be accompanied by a increased in flexural strength. To determine the effect of the composition nano-cement was used variation of composition nano-cement 0%, 5%, 10%, 15%, and 20%. Specimens for compression test is a cylindrical 10 cm diameter and 20 cm high, and Specimens for flexural test is 15 x 15 x 60 cm. The tools used in the testing is a load cell, LVDT (Linear Variable Displacement Transducer), and data loggers. Through this research is expected, in addition to knowing its effects on concrete compressive strength and flexural strength, can also determine relationship between compressive strength and flexural strength

    Quantum Monte Carlo Method for Attractive Coulomb Potentials

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    Starting from an exact lower bound on the imaginary-time propagator, we present a Path-Integral Quantum Monte Carlo method that can handle singular attractive potentials. We illustrate the basic ideas of this Quantum Monte Carlo algorithm by simulating the ground state of hydrogen and helium.Comment: 7 pages, 3 table

    Gauge Theory for Quantum Spin Glasses

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    The gauge theory for random spin systems is extended to quantum spin glasses to derive a number of exact and/or rigorous results. The transverse Ising model and the quantum gauge glass are shown to be gauge invariant. For these models, an identity is proved that the expectation value of the gauge invariant operator in the ferromagnetic limit is equal to the one in the classical equilibrium state on the Nishimori line. As a result, a set of inequalities for the correlation function are proved, which restrict the location of the ordered phase. It is also proved that there is no long-range order in the two-dimensional quantum gauge glass in the ground state. The phase diagram for the quantum XY Mattis model is determined.Comment: 15 pages, 2 figure

    Effects on osteoclast and osteoblast activities in cultured mouse calvarial bones by synovial fluids from patients with a loose joint prosthesis and from osteoarthritis patients

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    Aseptic loosening of a joint prosthesis is associated with remodelling of bone tissue in the vicinity of the prosthesis. In the present study, we investigated the effects of synovial fluid (SF) from patients with a loose prosthetic component and periprosthetic osteolysis on osteoclast and osteoblast activities in vitro and made comparisons with the effects of SF from patients with osteoarthritis (OA). Bone resorption was assessed by the release of calcium 45 ((45)Ca) from cultured calvariae. The mRNA expression in calvarial bones of molecules known to be involved in osteoclast and osteoblast differentiation was assessed using semi-quantitative reverse transcription-polymerase chain reaction (PCR) and real-time PCR. SFs from patients with a loose joint prosthesis and patients with OA, but not SFs from healthy subjects, significantly enhanced (45)Ca release, effects associated with increased mRNA expression of calcitonin receptor and tartrate-resistant acid phosphatase. The mRNA expression of receptor activator of nuclear factor-kappa-B ligand (rankl) and osteoprotegerin (opg) was enhanced by SFs from both patient categories. The mRNA expressions of nfat2 (nuclear factor of activated T cells 2) and oscar (osteoclast-associated receptor) were enhanced only by SFs from patients with OA, whereas the mRNA expressions of dap12 (DNAX-activating protein 12) and fcrÎł (Fc receptor common gamma subunit) were not affected by either of the two SF types. Bone resorption induced by SFs was inhibited by addition of OPG. Antibodies neutralising interleukin (IL)-1α, IL-1ÎČ, soluble IL-6 receptor, IL-17, or tumour necrosis factor-α, when added to individual SFs, only occasionally decreased the bone-resorbing activity. The mRNA expression of alkaline phosphatase and osteocalcin was increased by SFs from patients with OA, whereas only osteocalcin mRNA was increased by SFs from patients with a loose prosthesis. Our findings demonstrate the presence of a factor (or factors) stimulating both osteoclast and osteoblast activities in SFs from patients with a loose joint prosthesis and periprosthetic osteolysis as well as in SFs from patients with OA. SF-induced bone resorption was dependent on activation of the RANKL/RANK/OPG pathway. The bone-resorbing activity could not be attributed solely to any of the known pro-inflammatory cytokines, well known to stimulate bone resorption, or to RANKL or prostaglandin E(2 )in SFs. The data indicate that SFs from patients with a loose prosthesis or with OA stimulate bone resorption and that SFs from patients with OA are more prone to enhance bone formation

    Deformation of Quantum Dots in the Coulomb Blockade Regime

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    We extend the theory of Coulomb blockade oscillations to quantum dots which are deformed by the confining potential. We show that shape deformations can generate sequences of conductance resonances which carry the same internal wavefunction. This fact may cause strong correlations of neighboring conductance peaks. We demonstrate the relevance of our results for the interpretation of recent experiments on semiconductor quantum dots.Comment: 4 pages, Revtex, 4 postscript figure

    High prevalence of functional vitamin deficiencies in a psychogeriatric ward

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    Choline (Ch) is involved in relevant neurochemical processes. It is the precursor and metabolite of acetylcholine (ACh). It plays a role in single-carbon metabolism and is an essential component of different membrane phospholipids (PLs). These PLs are structural components of cell membranes, and involved in intraneuronal signal transduction. An increased ACh release was found after Ch treatment in rat corpus striatum slices. An in vivo proton magnetic resonance study has analyzed Ch ingestion effect. This work which represents the first non invasive study for exploring in vivo human brain neurochemistry showed the transfer of an oral Ch load in the brain of normal volunteers. These results were not confirmed by other in vivo studies. Cellular membranes breakdown is suggested as a feature of neurodegeneration in acute (stroke) and chronic (Alzheimer’s and vascular dementias) brain disorders. The effects of exogenous CCPLs on different brain areas were largely studied. Our group has assessed the influence of treatment with the CCPL, choline alphoscerate (GPC) on brain cholinergic neurotransmission markers in an animal model of brain vascular injury. A neuroprotective effect of GPC alone or in association with acetylcholinesterase inhibitor, galantamine was found. These results suggest that GPC could stimulate the expression of vesicular ACh transporter and Ch transporter primarily in areas involved in cognitive processes. These cholinergic markers could represent an appropriate mean to investigate brain cholinergic pathways. In the lack of novel therapeutic strategies, safe compounds developed since a long time such as the CCPLs could have still a place in pharmacotherapy and would merit to be investigated by new clinical studies

    Heretability and Correlation of Vegetative and Generative Character on Genotypes of Jatropha (Jatropha curcas Linn.)

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    AbstractThis study was aimed to obtain information of heritability predictive value and correlations of vegetative and generative characters on six genotypes of J. curcas. The characters of plant height, leaf number, leaf width, number of primary and secondary branches, number of fruit bunches, number of fruits per plant, seed's and 100 seeds’ dry weight showed high predictive value of heritability. Characters related to positive correlation and high heritability values (leaf width, number of primary branches, number of secondary branches, number of fruit bunches, number of fruits per plant) are able to be used as criteria for selection of J. curcas plant
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