33,128 research outputs found
Comparative Enumeration Gene Expression
This paper is about differential gene expression measured by transcript counting methods such as SAGE or MPSS. It introduces two significance tests for detection of differential expressed tags: frequentist and Bayesian. Under the frequentist view, it is proposed a test that computes the critical level as a function of each tag total frequency. Under the Bayesian view the Full Bayesian Significance Test is used considering the logistic normal distribution. The two proposed significance levels, the frequentist and the Bayesian, are compared for a data set with four libraries. The linking function between them is a Beta distribution function with mean 0.39 and standard deviation 0.30
Normal Heat Conduction in a Chain with Weak Interparticle Anharmonic Potential
We analytically study heat conduction in a chain with interparticle
interaction V(x)=lambda[1-cos(x)] and harmonic on-site potential. We start with
each site of the system connected to a Langevin heat bath, and investigate the
case of small coupling for the interior sites in order to understand the
behavior of the system with thermal reservoirs at the boundaries only. We
study, in a perturbative analysis, the heat current in the steady state of the
one-dimensional system with weak interparticle potential. We obtain an
expression for the thermal conductivity, compare the low and high temperature
regimes, and show that, as we turn off the couplings with the interior heat
baths, there is a "phase transition:'' the Fourier's law holds only at high
temperatures
Space-time Torsion and Neutrino Oscillations in Vacuum
The objective of this study is to verify the consistency of the prescription
of alternative minimum coupling (connection) proposed by the Teleparallel
Equivalent to General Relativity (TEGR) for the Dirac equation. With this aim,
we studied the problem of neutrino oscillations in Weitzenbock space-time in
the Schwarzschild metric. In particular, we calculate the phase dynamics of
neutrinos. The relation of spin of the neutrino with the space-time torsion is
clarified through the determination of the phase differences between spin
eigenstates of the neutrinos.Comment: 07 pages, no figure
Geoconservation education: the leading role of the University of Minho (Portugal)
In the University of Minho the first works concerning geoconservation were developed in 1996 in the Earth Sciences Department but it was only in 2005 that a major step was taken by this university with the creation of the master course on Geological Heritage and Geoconservation. Since that time, around 70 students were enrolled with an average of 10 new students each year. The University of Minho is also engaged with geoconservation at the PhD level. Several theses have been produced focused of themes centred in Portugal, Cape Verde and Brazil. In addition to post-graduation studies on geoconservation, there are also optional courses (5 ECTS) on geodiversity and geoconservation for the graduations on Geology, Biology and Geography. In what concerns non-formal education, the University of Minho has also some work done on raising public awareness of geoconservation through the organisation of guided fieldtrips to selected geosites, participation in TV documentaries and edition of publications
Quantitative assessment of geosites with national and international relevance in Portugal: methodological procedures
During the last years geoscientists of
various institutions have developed a
project aiming the establishment of a
geoconservation strategy in Portugal.
One of the main goals of this project was the
inventory of the most important Portuguese
the definition of the frameworks representing
the most important geological features in
Portugal and considering all geodiversity.
With the participation of more than seventy geoscientists, twenty-seven geological
frameworks were defined according to their
scientific value at both national and international levels. The scientific value together with the vulnerability was numerically assessed in order to obtain a sorted list of all
geosites with scientific value. The first step geosites. The Portuguese geosites inventory will be used in nature conservation policies and land-use strategies in different levels of country's administration
The inventory of the Portuguese geological heritage: a good example of scientific cooperation between universities
The first systematic inventory of the Portuguese geological heritage is a clear example of the academic collaboration that characterizes the geoconservation in Portugal. Three hundred and twenty six geosites with inter- national or national relevance have been inventoried under the scope of the scientific research project âIdentifica- tion, characterisation and conservation of geological heritage: a geoconservation strategy for Portugalâ. The geosites were selected exclusively based on their scientific value and support twenty-seven frameworks. For each geological framework a leading geoscientist from a university was responsible for the scientific characterization of the framework, to invite collaborators to identify representative geosites, and to assess the scientific value and vulnerability of the geosites. In the end, seventy geoscientists, mainly from universities, took part in the scientific results that are now important raw data to support nature conservation initiatives
The genetic architecture of emerging fungicide resistance in populations of a global wheat pathogen
Containing fungal diseases often depends on the application of fungicidal compounds. Fungicides can rapidly lose effectiveness due to the rise of resistant individuals in populations. However, the lack of knowledge about resistance mutations beyond known target genes challenges investigations into pathways to resistance. We used whole-genome sequencing data and association mapping to reveal the multilocus genetic architecture of fungicide resistance in a global panel of 159 isolates of Parastagonospora nodorum, an important fungal pathogen of wheat. We found significant differences in azole resistance among global field populations. The populations evolved distinctive combinations of resistance alleles which can interact when co-occurring in the same genetic background. We identified 34 significantly associated single nucleotide polymorphisms located in close proximity to genes associated with fungicide resistance in other fungi, including a major facilitator superfamily transporter. Using fungal colony growth rates and melanin production at different temperatures as fitness proxies, we found no evidence that resistance was constrained by genetic trade-offs. Our study demonstrates how genome-wide association studies of a global collection of pathogen strains can recapitulate the emergence of fungicide resistance. The distinct complement of resistance mutations found among populations illustrates how the evolutionary trajectory of fungicide adaptation can be complex and challenging to predict
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