1,080 research outputs found

    Dangers of Indiscriminate Antibiotic Use

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    The introduction of antibiotics into therapy during the past ten years has provided a potent weapon against many diseases. The apparent innocuous nature and low toxicity of these drugs qualified them for the label of miracle drugs. The antibiotics have altered therapeutics to an amazing degree, and have done much in overcoming the dangers of some types of diseases. However, like high powered bullets, they can be dangerous if uncontrolled. Unlike most other drugs, antibiotics do not have a self-limiting cure-or-kill basis, but have ramifications of undesirable effects which may persist to provide health hazards to an alarming degree not only to animals but to persons working with them. In recent years an increasing number of articles have appeared in the scientific literature on hazards associated with indiscriminate widespread use of these potent drugs. While recognizing the undisputed role of antibiotics in present day therapy, the subject of this report is concerned with undesirable effects and an evaluation of what present indiscriminate use of antibiotics can lead to

    General CMB and Primordial Bispectrum Estimation I: Mode Expansion, Map-Making and Measures of f_NL

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    We present a detailed implementation of two bispectrum estimation methods which can be applied to general non-separable primordial and CMB bispectra. The method exploits bispectrum mode decompositions on the domain of allowed wavenumber or multipole values. Concrete mode examples constructed from symmetrised tetrahedral polynomials are given, demonstrating rapid convergence for known bispectra. We use these modes to generate simulated CMB maps of high resolution (l > 2000) given an arbitrary primordial power spectrum and bispectrum or an arbitrary late-time CMB angular power spectrum and bispectrum. By extracting coefficients for the same separable basis functions from an observational map, we are able to present an efficient and general f_NL estimator for a given theoretical model. The estimator has two versions comparing theoretical and observed coefficients at either primordial or late times, thus encompassing a wider range of models, including secondary anisotropies, lensing and cosmic strings. We provide examples and validation of both f_NL estimation methods by direct comparison with simulations in a WMAP-realistic context. In addition, we show how the full bispectrum can be extracted from observational maps using these mode expansions, irrespective of the theoretical model under study. We also propose a universal definition of the bispectrum parameter F_NL for more consistent comparison between theoretical models. We obtain WMAP5 estimates of f_NL for the equilateral model from both our primordial and late-time estimators which are consistent with each other, as well as with results already published in the literature. These general bispectrum estimation methods should prove useful for the analysis of nonGaussianity in the Planck satellite data, as well as in other contexts.Comment: 41 pages, 17 figure

    Constraining Variations in the Fine Structure Constant in the presence of Early Dark Energy

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    We discuss present and future cosmological constraints on variations of the fine structure constant α\alpha induced by an early dark energy component having the simplest allowed (linear) coupling to electromagnetism. We find that current cosmological data show no variation of the fine structure constant at recombination respect to the present-day value, with α\alpha / α0\alpha_0 = 0.975 \pm 0.020 at 95 % c.l., constraining the energy density in early dark energy to Ωe\Omega_e < 0.060 at 95 % c.l.. Moreover, we consider constraints on the parameter quantifying the strength of the coupling by the scalar field. We find that current cosmological constraints on the coupling are about 20 times weaker than those obtainable locally (which come from Equivalence Principle tests). However forthcoming or future missions, such as Planck Surveyor and CMBPol, can match and possibly even surpass the sensitivity of current local tests.Comment: 5 pages, 3 figure

    O problema da pesagem de bovinos no campo e o melhoramento genético.

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    O melhoramento genético utiliza dados de pesos ao nascimento, desmama, doze meses e aos dezoito meses para estimar componentes de variância e outros parâmetros genético afins

    Python I, II, and III CMB Anisotropy Measurement Constraints on Open and Flat-Lambda CDM Cosmogonies

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    We use Python I, II, and III cosmic microwave background anisotropy data to constrain cosmogonies. We account for the Python beamwidth and calibration uncertainties. We consider open and spatially-flat-Lambda cold dark matter cosmogonies, with nonrelativistic-mass density parameter Omega_0 in the range 0.1--1, baryonic-mass density parameter Omega_B in the range (0.005--0.029) h^{-2}, and age of the universe t_0 in the range (10--20) Gyr. Marginalizing over all parameters but Omega_0, the combined Python data favors an open (spatially-flat-Lambda) model with Omega_0 simeq 0.2 (0.1). At the 2 sigma confidence level model normalizations deduced from the combined Python data are mostly consistent with those drawn from the DMR, UCSB South Pole 1994, ARGO, MAX 4 and 5, White Dish, and SuZIE data sets.Comment: 20 pages, 7 figures, accepted by Ap

    Co-receptor and co-stimulation blockade for mixed chimerism and tolerance without myelosuppressive conditioning

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    BACKGROUND: A major challenge in the application of marrow transplantation as a route to immunological tolerance of a transplanted organ is to achieve hematopoietic stem cell (HSC) engraftment with minimal myelosuppressive treatments. RESULTS: We here describe a combined antibody protocol which can achieve long-term engraftment with clinically relevant doses of MHC-mismatched bone marrow, without the need for myelosuppressive drugs. Although not universally applicable in all strains, we achieved reliable engraftment in permissive strains with a two-stage strategy: involving first, treatment with anti-CD8 and anti-CD4 in advance of transplantation; and second, treatment with antibodies targeting CD4, CD8 and CD40L (CD154) at the time of marrow transplantation. Long-term mixed chimerism through co-receptor and co-stimulation blockade facilitated tolerance to donor-type skin grafts, without any evidence of donor-antigen driven regulatory T cells. CONCLUSION: We conclude that antibodies targeting co-receptor and co-stimulatory molecules synergise to enable mixed hematopoietic chimerism and central tolerance, showing that neither cytoreductive conditioning nor 'megadoses' of donor bone marrow are required for donor HSC to engraft in permissive strains

    ЕФЕКТИ НА ИЗЛИШЪКА НА Cu ВЪРХУ РАСТЕЖА И ФОТОСИНТЕЗАТА НА ЕЧЕМИЧНИ РАСТЕНИЯ. ВРЪЗКА СЪС СКРИНИНГ ТЕСТ ЗА ТОЛЕРАНТНОСТ КЪМ Cu

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    Twenty-day-old barley (Hordeum vulgare L. cv. Ribeka) plants grown as sand culture were exposed to Cu treatment (0, 10, 15 and 20 mg Cu kg-1 sand) for ten days. The effects of excess Cu on both growth and photosynthetic performance were studied in order to identify the most sensitive probes implicating a further development of screening test for Cu tolerance within barley genotypes. The results obtained indicated that stomata conductance and photosynthetic electron transport linked to PSII+OEC exhibited the highest sensitivity to excess Cu, followed by plant dry weigh accumulation, leaf area formation, net photosynthetic rate, photosynthetic electron transport linked to PSI and PSII-OEC. It was concluded that leaf gas exchange parameters, plant dry weight accumulation and leaf area formation present an effective plant test system for screening for barley genotypes with higher Cu tolerance.Двадесетдневни ечемични (Hordeum vulgare L. сорт Ribeka ) растения, отглеждани като пясъчна култура, са подложени на третиране с Cu (0, 10, 15 and 20 mg Cu kg-1 пясък) в продължение на 10 дни. Проучени са ефектите на излишъка на Cu върху растежа и фотосинтетичната активност на растенията с цел да се определят най-чувствителните индикатори във връзка с понататъшното разработване на тест за скрининг на толерантни към Cu ечемични генотипове. Получените резултати показват, че с най-висока чувствителност към Cu са устичната проводимост, фотосинтетичния електронен транспорт свързан с PSII+OEC, следвани от натрупването на суха маса в растенията, формирането на листната площ, нето скоростта на фотосинтезата, фотосинтетичния електронен транспорт свързан с PSI и PSIIOEC. Заключава се, че листният газообмен, натрупването на суха маса и формирането на листна площ представляват ефективна растителна система за скрининг за ечемични генотипове с по-висока толерантност към Cu
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