116 research outputs found
(Ruminal methane emission related aspects in cattle production systems
Methane is well known as a greenhouse
effect intensifier. Ruminants, during the ruminal digestive
fermentation process, transform carbohydrates available
in the diet to volatile fatty acids, with production of carbon
dioxide and methane. Therefore, ruminants are known
as important methane source to the atmosphere.
Methane production also means animal losses of
ingested energy. Ruminal fermentation process is driven
by dry matter intake, and feed quality. Therefore,
consume of low quality diets will produce more methane
per product unit (milk or beef) compared to high
producing animals ingesting great amounts of high quality
diets. The sulphur hex fluoride gas tracer technique did
allow good methane emission measurements by grazing
or free managed animals. Results show that the
reduction of methane emission by cattle is related to
better quality diet, to improvement of forage quality of
pastures, to grain inclusion in diet, to animal breeds with
greater production potential, and other practices that
improve production efficiency, and result in shorter
production cycles.O gás metano possui reconhecidamente
um importante papel como intensificador do efeito
estufa. Pelo seu processo digestivo de fermentação
entérica, os ruminantes convertem os carboidratos
presentes na dieta em ácidos graxos voláteis,
resultando na produção de dióxido de carbono e
metano. Dessa forma, os ruminantes são
reconhecidos como importantes emissores de
metano ruminal para a atmosfera, sendo que a
produção deste gás representa ainda perdas
energéticas para os animais em relação à energia
consumida. Animais consumindo dietas de baixa
qualidade podem produzir mais metano por unidade
de produto (carne ou leite) em relação aos animais
de alta produção consumindo dietas de melhor
qualidade em maiores níveis de ingestão. Resultados
têm mostrado que a redução da emissão de metano
pela pecuária está ligada à melhoria da dieta, à
melhoria dos pastos, à suplementação alimentar, à
seleção por maior potencial genético de produção e
a outras medidas que reflitam na melhor eficiência
produtiva, resultando em menores ciclos de
produção
Rare Variants in 48 Genes Account for 42% of Cases of Epilepsy With or Without Neurodevelopmental Delay in 246 Pediatric Patients
In order to characterize the genetic architecture of epilepsy in a pediatric population from the Iberian Peninsula (including the Canary Islands), we conducted targeted exome sequencing of 246 patients with infantile-onset seizures with or without neurodevelopmental delay. We detected 107 variants in 48 different genes, which were implicated in neuronal excitability, neurodevelopment, synaptic transmission, and metabolic pathways. In 104 cases (42%) we detected variant(s) that we classified as pathogenic or likely pathogenic. Of the 48 mutated genes, 32 were dominant, 8 recessive and 8 X-linked. Of the patients for whom family studies could be performed and in whom pathogenic variants were identified in dominant or X-linked genes, 82% carried de novo mutations. The involvement of small copy number variations (CNVs) is 9%. The use of progressively updated custom panels with high mean vertical coverage enabled establishment of a definitive diagnosis in a large proportion of cases (42%) and detection of CNVs (even duplications) with high fidelity. In 10.5% of patients we detected associations that are pending confirmation via functional and/or familial studies. Our findings had important consequences for the clinical management of the probands, since a large proportion of the cohort had been clinically misdiagnosed, and their families were subsequently able to avail of genetic counseling. In some cases, a more appropriate treatment was selected for the patient in question, or an inappropriate treatment discontinued. Our findings suggest the existence of modifier genes that may explain the incomplete penetrance of some epilepsy-related genes. We discuss possible reasons for non-diagnosis and future research directions. Further studies will be required to uncover the roles of structural variants, epimutations, and oligogenic inheritance in epilepsy, thereby providing a more complete molecular picture of this disease. In summary, given the broad phenotypic spectrum of most epilepsy-related genes, efficient genomic tools like the targeted exome sequencing panel described here are essential for early diagnosis and treatment, and should be implemented as first-tier diagnostic tools for children with epilepsy without a clear etiologic basis
Produção e composição bromatológica de vinte e cinco genótipos de sorgo (Sorghum bicolor (L.) Moench)
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
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Diversity and nitrogen fixation efficiency of rhizobia isolated from nodules of Centrolobium paraense
Fontes de fósforo em suplementos minerais para bovinos de corte em pastagem de Cynodon nlemfuensis Vanderyst
Cinética e parâmetros de fermentação ruminal in vitro de silagens de parte aérea e raízes de mandioca
Forage yield and grazing efficiency on rotationally stocked pastures of 'Tanzania-1' guineagrass and 'Guaçu' elephantgrass
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