711 research outputs found

    Evidence for narrow resonant structures at W≈1.68W \approx 1.68 and W≈1.72W \approx 1.72 GeV in real Compton scattering off the proton

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    First measurement of the beam asymmetry Σ\Sigma for Compton scattering off the proton in the energy range Eγ=0.85−1.25E_{\gamma}=0.85 - 1.25 GeV is presented. The data reveals two narrow structures at Eγ=1.036E_{\gamma}= 1.036 and Eγ=1.119E_{\gamma}=1.119 GeV. They may signal narrow resonances with masses near 1.681.68 and 1.721.72 GeV, or they may be generated by the sub-threshold KΛK\Lambda and ωp\omega p production. Their decisive identification requires additional theoretical and experimental efforts.Comment: Published versio

    Stochastic Resonance in Two Dimensional Landau Ginzburg Equation

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    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

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    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

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    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

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    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

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    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

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    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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