1,080 research outputs found
Dangers of Indiscriminate Antibiotic Use
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
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
We discuss present and future cosmological constraints on variations of the
fine structure constant 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 / =
0.975 \pm 0.020 at 95 % c.l., constraining the energy density in early dark
energy to < 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.
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
Micropropagação de Eucalyptus citriodora e Eucalyptus tereticornis.
Edição dos Anais do Congresso Florestal Brasileiro, 6., 1990, Campos do Jordão
Python I, II, and III CMB Anisotropy Measurement Constraints on Open and Flat-Lambda CDM Cosmogonies
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
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
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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