1,705 research outputs found
FCNC in the 3-3-1 model with right-handed neutrinos
Flavor changing neutral currents coming from a new non-universal neutral
Gauge-Boson and from the non-unitary quark mixing matrix for the
model with right handed neutrinos are
studied. By imposing as experimental constraints the measured values of the 3x3
quark mixing matrix, the neutral meson mixing, and the bounds measured values
for direct flavor changing neutral current processes, the largest mixing of the
known quarks with the exotic ones can be established, with new sources of
flavor changing neutral currents being identified. Our main result is that for
a value smaller than one, large rates of rare top decays such as
, , and (where g stands for the gluon field)
are obtained; but if the model can survive present
experimental limits only if the mass of the new neutral Gauge Boson becomes
larger that 10 TeV.Comment: 30 pages, 1 figure. Accepted for publication in Phys. Rev.
Como prevenir surtos de cenurose no rebanho ovino.
O que é cenurose; Quais são os sintomas; Como é o ciclo evolutivo; Como tratar os ovinos; O que pode ser feito com ovinos com cenurose; Como prevenir; Esquema de tratamento dos cães.bitstream/item/63865/1/CO63.pdfDisponÃvel no formato online
The use of artificial neural networks to diagnose mastitis in dairy cattle
The use of milk sample categorization for diagnosing mastitis using Kohonen's self-organizing feature map (SOFM) is reported. Milk trait data of 14 weeks of milking from commercial dairy cows in New Zealand was used to train and test a SOFM network. The SOFM network was useful in discriminating data patterns into four separate mastitis categories. Several other artificial neural networks were tested to predict the missing data from the recorded milk traits. A multi-layer perceptron (MLP) network proved to be most accurate (R² = 0.84, r = 0.92) when compared to other MLP (R² = 0.83, r = 0.92), Elman (R² = 0.80, r = 0.92), Jordan (R² = 0.81, r = 0.92) or linear regression (R² = 0.72, r = 0.85) methods. It is concluded that the SOFM can be used as a decision tool for the dairy farmer to reduce the incidence of mastitis in the dairy herd
Mesopelagic N-2 fixation related to organic matter composition in the Solomon and Bismarck Seas (Southwest Pacific)
Dinitrogen (N-2) fixation was investigated together with organic matter composition in the mesopelagic zone of the Bismarck (Transect 1) and Solomon (Transect 2) Seas (Southwest Pacific). Transparent exopolymer particles (TEP) and the presence of compounds sharing molecular formulae with saturated fatty acids and sugars, as well as dissolved organic matter (DOM) compounds containing nitrogen (N) and phosphorus (P) were higher on Transect 1 than on Transect 2, while oxygen concentrations showed an opposite pattern. N-2 fixation rates (up to similar to 1 nmol N L-1 d(-1)) were higher in Transect 1 than in Transect 2, and correlated positively with TEP, suggesting a dependence of diazotroph activity on organic matter. The scores of the multivariate ordination of DOM molecular formulae and their relative abundance correlated negatively with bacterial abundances and positively with N-2 fixation rates, suggesting an active bacterial exploitation of DOM and its use to sustain diazotrophic activity. Sequences of the nifH gene clustered with Alpha-, Beta-, Gamma- and Deltaproteobacteria, and included representatives from Clusters I, III and IV. A third of the clone library included sequences close to the potentially anaerobic Cluster III, suggesting that N-2 fixation was partially supported by presumably particle-attached diazotrophs. Quantitative polymerase chain reaction (qPCR) primer-probe sets were designed for three phylotypes and showed low abundances, with a phylotype within Cluster III at up to 10(3) nifH gene copies L-1. These results provide new insights into the ecology of non-cyanobacterial diazotrophs and suggest that organic matter sustains their activity in the mesopelagic ocean
Longitudinal variability of diazotroph abundances in the subtropical North Atlantic Ocean
Diazotrophy-related studies in the North Atlantic have largely focused on its western tropical area, leaving the subtropics and the east undersampled. We studied the longitudinal distribution of Trichodesmium, UCYN-A, UCYN-B, the putative Gammaproteobacterium g-24774A11 and Richelia (Het1) along 24.58N, using quantitative polymerase chain reaction on different size fractions (10, 10–3 and 3–0.2 mm) and additional filament counts for Trichodesmium. Trichodesmium was the most abundant phylotype, followed by UCYN-A, g-24774A11 and Het1, with maximum abundances of 8.8 ! 105, 2.0 ! 105, 3.3 ! 103 and 3.4 ! 102 nifH copies L21, respectively, whereas UCYN-B was mostly undetected. A clear shift in the diazotroph community was observed at !308W, coinciding with the transition between the North Atlantic Subtropical Gyre boundary and inner core. This transition zone divided the transect into an eastern half dominated by UCYN-A and western half dominated by Trichodesmium and g-24774A11. g-24774A11
was only detected in the 10–3 mm fraction, suggesting their association with larger microbes or aggregates. Our results indicate that typical size fractionation by 10 mm is not optimal for reconciling diazotroph phylotypes to N2 fixation rates and that non-cyanobacterial diazotrophs may contribute importantly to bulk diazotrophic activity in the western subtropical North Atlantic.Consolider-Malaspina (CSD2008-00077), CAIBEX (CTM2007-66408- CO2-02). HOTMIX (CTM2011-30010-CO2-01)Versión del editor1,749
Genetic variation in the eastern subterranean termite Reticulitermes flavipes (Isoptera: Rhinotermitidae)
The eastern subterranean termite, Reticulitermes flavipes, is the most widely dispersed termite in North America. The genus Reticulitermes spp. is responsible for 80% of total termite damage caused to urban structures each year. Little is known about the genetic structure of termites, particularly at the colony level. Evidence for what genetically defines a termite colony is a hotly debated topic in current literature due to the implications such findings would have regarding current lawsuits against pest control operations. Information on termite genetic structure is sparse.
In this study, the genetic variation and gene flow among Texas populations of R. flavipes at the statewide level and city level was examined. A 324-337 base pairs segment of the mtDNA, AT-rich region was a polymerase chain reaction amplified from 104 different termite specimens from 12 Texas cities. The DNA extracts were then subjected to PCR amplification using specific primers and it was then sequenced. Using the sequence data and appropriate statistical measures it was found that, at the statewide level, nucleotide and haplotypic diversity is low. Gene flow was found to be low on a statewide basis. At the city level nucleotide and haplotypic diversity was high. The findings of this study provide insights into termite genetic structure
Mermelada de papaya
Una de las frutas perecederas más difÃcil de conservar es la papaya; la cual al llegar a su punto de madurez exige ser consumida rápidamente, hecho que ha venido ocasionando pérdidas considerables tanto al productor como al consumidor: especialmente en épocas de cosecha. La siguiente cartilla es una alternativa a ese problema, en donde se explicará paso a paso la forma de elaborar Mermelada de Papaya.Introducción -- Objetivo general -- Proceso -- Cuadro de registro -- Seguridad e higienenaDocumento sin fecha. Se aproxima la fecha a la década.11 página
Cuidados com cordeiros hipotérmicos.
A mortalidade perinatal de cordeiros ainda é um dos grandes gargalos na produção ovina em condições extensivas de criação. Alguns estudos apontam o complexo inanição-exposição (inabilidade de mamar acompanhada de frio e/ou chuva) como responsável por 40 a 80% das perdas de cordeiros antes da assinalação.bitstream/item/67091/1/CR-33-circular-tecnica-cuidados-com-cordeiros-hipotermicos.pd
Introgressão assistida por diagnóstico molecular da mutação Booroola em rebanhos comerciais das raças Texel e Corriedale.
A alta prolificidade das ovelhas Booroola é causada por uma mutação que ocorreu naturalmente no gene do receptor para proteÃnas morfogenéticas de osso tipo1 B (BMPR1B). A partir de 2001 o desenvolvimento de testes genéticos possibilitou o diagnóstico desta mutação através de PCR-RFLP
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