332 research outputs found

    Typical Gibbs configurations for the 1d Random Field Ising Model with long range interaction

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    We study a one--dimensional Ising spin systems with ferromagnetic, long--range interaction decaying as n^{-2+\a}, \a \in [0,\frac 12], in the presence of external random fields. We assume that the random fields are given by a collection of symmetric, independent, identically distributed real random variables, gaussian or subgaussian with variance θ\theta. We show that for temperature and variance of the randomness small enough, with an overwhelming probability with respect to the random fields, the typical configurations, within volumes centered at the origin whose size grow faster than any power of th1\th^{-1}, % {\bf around the origin} are intervals of ++ spins followed by intervals of - spins whose typical length is \simeq \th^{-\frac{2}{(1-2\a)}} for 0\le \a<1/2 and e1th2\simeq e^{\frac 1 {\th^{2}}} for \a=1/2

    Geometry of contours and Peierls estimates in d=1 Ising models

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    Following Fr\"ohlich and Spencer, we study one dimensional Ising spin systems with ferromagnetic, long range interactions which decay as xy2+α|x-y|^{-2+\alpha}, 0α1/20\leq \alpha\leq 1/2. We introduce a geometric description of the spin configurations in terms of triangles which play the role of contours and for which we establish Peierls bounds. This in particular yields a direct proof of the well known result by Dyson about phase transitions at low temperatures.Comment: 28 pages, 3 figure

    A note on the effect of pre-slaughter transport duration on nutrient composition and fatty acid profile of broiler breast meat

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    WOS: 000294933400008The aim of this study was to investigate the influence of pre-slaughter transport duration, as a stress factor, on nutrient and fatty acid composition of broiler breast meat. The study was conducted on 48 breast muscles obtained from Ross broilers slaughtered at the average weight of 1.8 or 2.6 kg, 36 and 46 days old, respectively. Transport duration was 1.5 or 3 h. Heavier broilers transported for longer duration had the higher protein content, while lighter broilers gave similar results. Lower moisture but higher lipid content was observed for the long transported broilers. Fatty acid composition was significantly influenced by body weight and transport duration: a lower content of PUFA was obtained for heavier broilers. Ratios of PUFA/SFA was lower in heavier broilers. A decrease in MUFA and a lower n-3/n-6 ratio was evidenced in the meat from broilers transported for longer duration.Abalioglu Yem; Soya ve Tekstil Sanayi A.SSupported by Abalioglu Yem, Soya ve Tekstil Sanayi A.

    The low-temperature phase of Kac-Ising models

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    We analyse the low temperature phase of ferromagnetic Kac-Ising models in dimensions d2d\geq 2. We show that if the range of interactions is \g^{-1}, then two disjoint translation invariant Gibbs states exist, if the inverse temperature \b satisfies \b -1\geq \g^\k where \k=\frac {d(1-\e)}{(2d+1)(d+1)}, for any \e>0. The prove involves the blocking procedure usual for Kac models and also a contour representation for the resulting long-range (almost) continuous spin system which is suitable for the use of a variant of the Peierls argument.Comment: 19pp, Plain Te

    Genetic characterization of local Italian breeds of chickens undergoing in situ conservation

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    The objectives of this study were to determine genetic variation and to analyze population structure of 6 Italian local chicken breeds involved in a conservation program. Twenty microsatellite markers were investigated in 337 birds belonging to 6 breeds: Ermellinata di Rovigo, Robusta Maculata, Robusta Lionata, Pepoi, Padovana, and Polverara; a commercial layer cross was used as reference. One hundred twelve alleles were detected in the overall population, with a mean number of 5.6 +/- 2.1 alleles per locus. For the local breeds, the observed and expected heterozygosity ranged from a minimum of 0.240 to a maximum of 0.413 and from 0.243 to 0.463 for the Pepoi and Polverara breeds, respectively. Deviation from Hardy-Weinberg equilibrium was observed in 5 breeds and in the commercial cross. The overall population heterozygote deficiency was 0.427, the average inbreeding coefficient was 0.097, and the heterozygote deficiency due to breed subdivisions was 0.437. Reynolds' distances were used to draw an unrooted neighbor-joining tree, which topology gave information on the genetic origin of these breeds and confirmed their known history. The estimated molecular kinship within a breed ranged from 0.559 to 0.769, evidencing high coancestry. Structure analysis was performed to detect the presence of population substructures. Inferred clusters corresponded to the different breeds, without presence of admixture. The exception was the Polverara breed, for which a more complex genetic structure was found. The results supported the decision of safeguarding these breeds as an important reservoir of genetic diversity and confirmed the usefulness of microsatellite markers to characterize and to monitor genetic variability in local chicken breeds

    genetic variation and population structure of italian native sheep breeds undergoing in situ conservation

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    The genetic variability and presence of population substructures in 4 native Northern Italian sheep breeds, Alpagota, Brogna, Foza, and Lamon, un- dergoing in situ conservation, and 1 widespread Italian breed, Bergamasca, were studied by investigating 19 microsatellite markers. The breeds showed considerable genetic variability in terms of number of alleles and heterozygosity, with the exception of Alpagota, which was the least variable (0.607). Nevertheless, a signifi- cant deficit of heterozygotes was observed in each breed due to rather increased levels of inbreeding or to the presence of population substructures, probably caused by increased genetic variation in the founder popula- tions. The analyses evidenced clear genetic differentia- tion (FST = 0.085), reduced levels of admixture, and presence of private alleles among the breeds, confirm- ing their genetic uniqueness. In particular, according to Reynolds genetic distances, Alpagota was the most differentiated, perhaps because it had been bred mostly in a rather isolated area. Loss of any of the investi- gated breeds would result in a loss of genetic diversity ranging from 0.5 to 1.6% of the total observed gene diversity. Results supported the decision to safeguard these breeds as important reservoirs of genetic diver- sity and suggested breeding and mating practices to maintain variability and to overcome within-breed sub- structures

    variation of genetic diversity over time in local italian chicken breeds undergoing in situ conservation

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    ABSTRACT The aim of this study was to analyze the variation of different genetic diversity measures in 5 Italian local chicken breeds over a 4-yr period of conservation. The local breeds were Ermellinata di Rovigo, Padovana, Pepoi, Robusta Lionata, and Robusta Maculata. A total of 368 samples were chosen for the analysis among the birds hatched in the years 2002 and 2006. Genetic variation over 30 microsatellite loci was analyzed. All 30 microsatellites were polymorphic, with a total number of alleles equal to 251, a mean (±SD) of 8.367 ± 3.378 across populations and 3.233 ± 1.338 within population. After 4 yr of conservation, a loss of alleles occurred for all the microsatellites, with the exception of 4 loci. The total number of alleles and expected heterozygosity estimates significantly decreased during the 4 yr of conservation, whereas no significant differences were detected for the microsatellites polymorphism information content or for the observed heterozygosity estimates. A decrease of the inbreeding coefficient occurred for all the breeds, with the exception of Padovana and Robusta Lionata. All populations showed evidence of a persistent significant deviation from Hardy-Weinberg equilibrium caused by an excess of homozygotes, except Robusta Maculata, which reached the equilibrium in 2006. For Pepoi, Padovana, Ermellinata di Rovigo, and Robusta Maculata, molecular coancestry increased significantly (

    Recurrence of non-hydropic sudden sensorineural hearing loss (SSNHL): a literature review

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    Sudden Sensorineural Hearing Loss (SSNHL) is typically defined as the acute onset (less than 3 days) of a perceptive hearing loss of more than 30dB over at least three contiguous frequencies on pure tone audiometry. The exact incidence of SSNHL is uncertain, since many patients have a rapid and spontaneous resolution of symptoms and therefore don’t reach medical attention. Estimate of incidence ranges from 5 to 20 per 100.000 individuals, and bilateral involvement is very rare; it increases in the older patients (&gt;65 yo)(77 per 100.000) the in younger population (&lt;18 yo)(11 per 100.000) [3]. The true incidence of paediatric SSNHL is not established in literature; 40% of examined child with SSNHL, showed anatomic abnormaliti
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