711 research outputs found
Evidence for narrow resonant structures at and GeV in real Compton scattering off the proton
First measurement of the beam asymmetry for Compton scattering off
the proton in the energy range GeV is presented. The
data reveals two narrow structures at and
GeV. They may signal narrow resonances with masses near
and GeV, or they may be generated by the sub-threshold
and production. Their decisive identification requires additional
theoretical and experimental efforts.Comment: Published versio
Stochastic Resonance in Two Dimensional Landau Ginzburg Equation
We study the mechanism of stochastic resonance in a two dimensional Landau
Ginzburg equation perturbed by a white noise. We shortly review how to
renormalize the equation in order to avoid ultraviolet divergences. Next we
show that the renormalization amplifies the effect of the small periodic
perturbation in the system. We finally argue that stochastic resonance can be
used to highlight the effect of renormalization in spatially extended system
with a bistable equilibria
Distribution of functional variants within Runs of Homozygosity in four Italian cattle breeds
Several methods have been used to identify genomic regions subjected to
selective sweeps. An alternative method can make use of runs of
homozygosity (ROH), defined as stretches of homozygous regions in a
genome. The aim of the present study was to detect selective sweeps using
ROH in four cattle breeds. Individuals of Cinisara (71), Modicana (72),Reggiana (168) and Italian Holstein (96) were genotyped with the Illumina
Bovine50SNP v2 BeadChip. To identify genomic regions that were most
commonly associated with ROH within each breed, the percentage of
occurrences of a single nucleotide polymorphism (SNP) in ROH was
calculated across animals. The genomic regions most commonly associated
with ROH were identified by selecting the top 1% of the SNPs most
commonly observed in ROH in each breed. This approach resulted in the
identification of 11 genomic regions in the Cinisara and Italian Holstein,
and 8 in Modicana and Reggiana showing increased frequency of ROH.
Generally, ROH patterns differed between breeds. There were two
commons genomic regions between breed pairs, and in particular one in
BTA6 between Modicana and Reggiana and one in BTA10 between Cinisara
and Italian Holstein. A highly homozygous region (> 45% of individuals
with ROH) was found only in Modicana breed in BTA6 (6:37,019,972-
39,069,719) within a QTL affecting milk fat and protein concentration. In
these genomic regions we identified from 126 to 347 genes for each breed.
According to Panther and KEGG database, a majority of the genes was
involved in multiple signaling and signal transduction pathways in a wide
variety of cellular and biochemical processes. Several of these genes were
also comprised in a list of genes related to phenotypes for which cattle
breeds have been subjected to strong positive selection. For most genes
associated with ROH islands, a biological link to traits such as milk yield
and composition, reproduction, immune response, coat colour, genetic
disorders and resistance/susceptibility to infectious and diseases, which are
known to be under selection, can be hypothesized. These results showed
that selective sweeps detected with ROH approach are shared among
breeds and that scanning the genome for ROH might be an alternative or
complementary strategy to detect selective sweep related with important
economically traits
Full-length sequencing and identification of novel polymorphisms in the ACACA gene of Valle del Belice sheep breed
The essential role of the acetyl-CoA carboxylase (ACACA) enzyme in milk fatty acid (FA) synthesis suggests that it may be responsible for the phenotypic variability observed in milk. Before attempting association analyses between this gene and/or enzyme and phenotypic traits, a study on the genetic variability within this locus is required. The aim of this work was to sequence the entire coding region of ACACA gene in Valle del Belice sheep breed to identify polymorphic sites. A total of 51 coding exons of ACACA gene were sequenced in 32 individuals of Valle del Belice sheep breed. Sequencing analysis and alignment of obtained sequences showed the presence of 23 polymorphic sites. The most polymorphic was exon 53 which showed presence of 12 single-nucleotide polymorphisms (SNPs), of which eight were missense mutations, caused amino acid changes and therefore may affect protein function or stability causing variation in phenotype. The identified polymorphisms showed high variability of the ACACA gene. Sequences analysis allowed to find six new SNPs in exon 53 (6832C>T; 6835C>A; 6840G>A; 6847G>T; 6852C>T and 6860G>C). A total of 31 haplotypes were inferred. Although this study could not provide association study with production traits, it shows finding of novel SNPs that might be important in future studies and laid the basis for further association analyses needed to evaluate the potential use of these SNPs as genetic markers for fat content and FAs composition in milk of Valle del Belice sheep breed
Force balance and membrane shedding at the Red Blood Cell surface
During the aging of the red-blood cell, or under conditions of extreme
echinocytosis, membrane is shed from the cell plasma membrane in the form of
nano-vesicles. We propose that this process is the result of the
self-adaptation of the membrane surface area to the elastic stress imposed by
the spectrin cytoskeleton, via the local buckling of membrane under increasing
cytoskeleton stiffness. This model introduces the concept of force balance as a
regulatory process at the cell membrane, and quantitatively reproduces the rate
of area loss in aging red-blood cells.Comment: 4 pages, 3 figure
Monitoring commercial starter culture development in presence of red grape pomace powder to produce polyphenol-enriched fresh ovine cheeses at industrial scale level
Red grape Nero d'Avola cultivar grape pomace powder (GPP) was applied during fresh ovine cheese production in order to increase polyphenol content. Before cheeses were produced, the bacteria of a freeze-dried commercial starter culture were isolated and tested in vitro against GPP. Two dominant strains, both resistant to GPP, were identified. Thestarter culture was inoculated in pasteurized ewe's milk and the curd was divided into two bulks, one added with 1% (w/w) GPP and another one GPP-free. GPP did not influence the starter culture development, since lactic acid bacteria (LAB) counts were 109 CFU/g in both cheeses at 30 d. To exclude the interference of indigenous LAB, the pasteurized milk was analyzed, and several colonies of presumptive LAB were isolated, purified and typed. Four strains were allotted into Enterococcus and Lacticaseibacillus genera. The direct comparison of the polymorphic profiles of cheese bacteria evidenced the dominance of the starter culture over milk LAB. The addition of GPP increased cheese total phenolic compounds by 0.42 g GAE/kg. Sensory evaluation indicated that GPP-enriched cheese was well appreciated by the judges, providing evidence that GPP is a suitable substrate to increase the availability of total phenolic content in fresh ovine cheese
Eta photoproduction off the neutron at GRAAL: Evidence for a resonant structure at W=1.67 GeV
New (preliminary) data on eta photoproduction off the neutron are presented.
These data reveal a resonant structure at W=1.67 GeV.Comment: 8 pages, 4 figures. Published in Proceedings of Workshop on the
Physics of Excited Nucleons NSTAR2004, Grenoble, France, March 24 - 27,
pg.19
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