1,760 research outputs found

    Hydrogen peroxide etching proves useful for germanium

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    Influence of process variations in the etching of germanium with hydrogen peroxide has been studied, along with damage effects due to radiation. The work advances the knowledge of the etching process for germanium

    Absence of long-range superconducting correlations in the frustrated 1/2-filled band Hubbard model

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    We present many-body calculations of superconducting pair-pair correlations in the ground state of the half-filled band Hubbard model on large anisotropic triangular lattices. Our calculations cover nearly the complete range of anisotropies between the square and isotropic triangular lattice limits. We find that the superconducting pair-pair correlations decrease monotonically with increasing onsite Hubbard interaction U for inter-pair distances greater than nearest neighbor. For the large lattices of interest here the distance dependence of the correlations approaches that for noninteracting electrons. Both these results are consistent with the absence of superconductivity in this model in the thermodynamic limit. We conclude that the effective 1/2-filled band Hubbard model, suggested by many authors to be appropriate for the kappa-(BEDT-TTF)-based organic charge-transfer solids, does not explain the superconducting transition in these materials.Comment: 9 pages, 7 figures. Revised version to appear in Phys. Rev.

    Neuro-Fuzzy Navigation Technique for Control of Mobile Robots

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    Antigens of a Human Breast Carcinoma Cell Line (BT 20). I. Synthesis of Serum Proteins, Membrane-Associated Antigens, and Oncofetal-Associated Antigens

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    The synthesis of various products by a human mammary cell line (BT 20) was studied by incorporation of 14Clabeled amino acids, choline, glucosamine, or galactosamine into nondialyzable materials. These products had molecular weights ranging from less than 12,300 daltons to more than 200,000 daltons. They were analyzed by immunoelectrophoresis and double diffusion in agar. Among the synthesized products, the following proteins were identified: β2-glycoprotein I, α2HS-glycoprotein, α2-lipoprotein, actin, β2-microglobulin, carcinoembryonic antigen, three oncofetal-associated antigens, and various erythrocyte membrane-associated antigens (namely, glycophorin). Synthesis of milk proteins was not detectable. Only the protein moiety of the glycophorin molecule seemed to be synthesized. The β2-microglobulin was synthesized in an unbound state as well as bound to a glycoprotein whose relationship with the transplantation or tumor antigens must be determined. The three oncofetal-associated antigens were also synthesized in vitro by human fetal tissues and neoplastic and dysplastic human mammary tissue

    Search for Technology to Maximise Pyrite utility in Bihar

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    Rapid increase in population growth rate is greatly affecting the economy of the country. The development in the field of food production is required to keep pace with the increase of the population which is added every year, depite the boost provided by green revolution duly aided by the latest water-management techniques, which have largely helped in increasing the agricultural prod-uction.production. Thus our Nation continues to be under the threat of food scarcity even today. To meet the chall-enge of this threat agricultural output perforce, has to be stepped up from the available land. Besides the exis-ting vast tract of barren land, some of the present fertile land is also becoming barren due to its conti-nuous use. Thus in the present context, need for recl-aiming and replenishing the sick alkaline or acidic soils of the country and Bihar in particular is a necessity

    Lyman Alpha Emitter Evolution in the Reionization Epoch

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    Combining cosmological SPH simulations with a previously developed Lyman Alpha production/transmission model and the Early Reionization Model (ERM, reionization ends at redshift z~7), we obtain Lyman Alpha and UV Luminosity Functions (LFs) for Lyman Alpha Emitters (LAEs) for redshifts between 5.7 and 7.6. Matching model results to observations at z~5.7 requires escape fractions of Lyman Alpha, f_alpha=0.3, and UV (non-ionizing) continuum photons, f_c=0.22, corresponding to a color excess, E(B-V)=0.15. We find that (i) f_c increases towards higher redshifts, due the decreasing mean dust content of galaxies, (ii) the evolution of f_alpha/f_c hints at the dust content of the ISM becoming progressively inhomogeneous/clumped with decreasing redshift. The clustering photoionization boost is important during the initial reionization phases but has little effect on the Lyman Alpha LF for a highly ionized IGM. Halo (stellar) masses are in the range 10.0 < \log M_h < 11.8 (8.1 < \log M_* < 10.4) with M_h \propto M_*^{0.64}. The star formation rates are between 3-120 solar masses per year, mass-weighted mean ages are greater than 20 Myr at all redshifts, while the mean stellar metallicity increases from Z=0.12 to 0.22 solar metallicity from z~7.6 to z~5.7; both age and metallicity positively correlate with stellar mass. The brightest LAEs are all characterized by large star formation rates and intermediate ages (~200 Myr), while objects in the faint end of the Lyman Alpha LF show large age and star formation rate spreads. With no more free parameters, the Spectral Energy Distributions of three LAE at z~5.7 observed by Lai et al. (2007) are well reproduced by an intermediate age (182-220 Myr) stellar population and the above E(B-V) value.Comment: 13 pages, 9 figures, accepted to MNRA

    SF6 arc spectroscopy

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    Terminology and tensions within evidence-informed decision-making in South Africa over a 15-year period

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    In this article, we examine a key premise underlying evidence-informed decisionmaking (EIDM) – that research is for all, including service users and potential users, service providers and a wide range of decision-makers, from those running local services to national government officials and international agencies. Qualitative data collected on terminology used when writing and talking about EIDM over a period of 15 years during the implementation of a number of capacity development programmes in South Africa were combined with critical reflections in practice. Findings reveal that tensions exist in the titles and terminology used to describe the relationships between academia and government or between research and policy, and that these tensions have shifted over time, but not necessarily diminished. An analysis and critique of this terminology is provided to identify and unpack these tensions, which challenge the central premise of 'research for all'. The perpetuation of divisive labels that profile people, of job titles and specific terminology that describe agency, as well as the use of technical language, continues to exclude people from the approach. These have the effect of setting up users against producers of evidence. In conclusion, we challenge the advocates of the EIDM approach to review language and terminology to be more inclusive, to enable relationship-building and ease the process of engagement to ensure evidence-informed decision-making is true to its premise that research is for all

    Childhood Obstructive Sleep Apnea

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    Obstructive sleep apnea (OSA) is a common condition in childhood and can result insevere complications if left untreated. It is showing a rising trend in India. A significantassociation with obesity has been observed; however, some children with enlargedtonsils and/or adenoids may even be underweight. The patient usually presents withsnoring and other respiratory problems like mouth breathing, choking and gaspingepisodes in night. Poor school performance and neurocognitive deficits have beenreported. Pulmonary hypertension and cor pulmonale are seen in severe cases. Besidesthe history and clinical examination, for definitive diagnosis an overnightpolysomnographic evaluation is the gold standard. In all cases, the specific treatmentranges from simple lifestyle modifications and medications to surgeries likeadenotonsillectomy. Early diagnosis is vital.Key words: Childhood OSA, Obesity, adenotonsillar hypertroph

    Prevention of Fungal Growth on Rubber Earpads of Telecommunication Equipments

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    This paper recommends an addition of 100% zinc oxide to the rubber composition during its manufacture to effectively prevent fungal growth on the earpads without producing any adverse on its materials/performance or the user
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