Evidence of anomalous dispersion of the generalized sound velocity in glasses

The dynamic structure factor, S(Q,w), of vitreous silica, has been measured by inelastic X-ray scattering in the exchanged wavevector (Q) region Q=4-16.5 nm-1 and up to energies hw=115 meV in the Stokes side. The unprecedented statistical accuracy in such an extended energy range allows to accurately determine the longitudinal current spectra, and the energies of the vibrational excitations. The simultaneous observation of two excitations in the acoustic region, and the persistence of propagating sound waves up to Q values comparable with the (pseudo-)Brillouin zone edge, allow to observe a positive dispersion in the generalized sound velocity that, around Q=5 nm-1, varies from 6500 to 9000 m/s: this phenomenon was never experimentally observed in a glass.Comment: 5 pages, 3 figures. To appear in Phys. Rev.

Selection signatures of fat tail in sheep

The investigation of the genes with a role in lipid metabolism enjoy considerable scientific and commercial interest because of the strong correlations between fat deposition and the risk of cardiovascular disease. The fat tail characteristic of sheep is the adaptive response to harsh environment, and beyond representing a valuable energy reserve for facing future climate changes provides clues for elucidating the physiology of fat deposition. Studies on various sheep populations detected fat-tail signatures on chromosomes 2, 3, 5, 6, 7 and 13. Fat-tailed sheep represent about 25% of the world\u2019s sheep population, and the genes with a role in this phenotype are likely not the same for every breed, since the wild ancestor of sheep had a thin tail, and the fat tail was selected by humans in longstanding husbandry practices in different regions. In the present work, a genome-wide scan using ~50,000 Single Nucleotide Polymorphisms was performed to identify selection signatures for the f at tail in the Barbaresca sheep, an Italian breed originating from North Africa. Fst values of differentiation, and \u3c72 test of significance of allele frequency were calculated, for each marker, between the Barbaresca and each of 13 Italian thin-tailed breeds. Strong signals of selection were detected for all 13 breeds on chromosome 6, in a region encoding the SLIT homolog 2 gene, this gene acting as a molecular guidance cue in cellular migration. The signature on chromosome 7 was very strong only in some of the breeds used for comparison: the detected signal was located in proximity of the Vertnin gene, a candidate for variation in vertebral number, and was already revealed in Iranian and Mediterranean fat-tailed breeds, but not in the Chinese sheep, so confirming the complexity of the fat-tail phenotype, which is associated in some breeds to long and pendulous tail, while, in other breeds, to the short tail

Evaluation of three new surface irrigation parameterizations in the WRF-ARW v3.8.1 model: the Po Valley (Italy) case study

Abstract. Irrigation is a method of land management that can affect the local climate. Recent literature shows that it affects mostly the near-surface variables and it is associated with an irrigation cooling effect. However, there is no common parameterization that also accounts for a realistic water amount, and this factor could ascribe one cause to the different impacts found in previous studies. This work aims to introduce three new surface irrigation parameterizations within the WRF-ARW model (v3.8.1) that consider different evaporative processes. The parameterizations are tested on one of the regions where global studies disagree on the signal of irrigation: the Mediterranean area and in particular the Po Valley. Three sets of experiments are performed using the same irrigation water amount of 5.7 mm d−1, derived from Eurostat data. Two complementary validations are performed for July 2015: monthly mean, minimum, and maximum temperature with ground stations and potential evapotranspiration with the MODIS product. All tests show that for both mean and maximum temperature, as well as potential evapotranspiration simulated fields approximate observation-based values better when using the irrigation parameterizations. This study addresses the sensitivity of the results to human-decision assumptions of the parameterizations: start time, length, and frequency. The main impact of irrigation on surface variables such as soil moisture is due to the parameterization choice itself affecting evaporation, rather than the timing. Moreover, on average, the atmosphere and soil variables are not very sensitive to the parameterization assumptions for realistic timing and length

Growth, carcass and meat quality of Casertana, Italian Large White and Duroc x (Landrace x Italian Large White) pigs reared outdoors

To compare growth, skeletal development, carcass traits and meat quality of different genotypes, 10 Casertana (CT), 10 Italian Large White (LW) and 10 Duroc x (Landrace x Italian Large White) (DU) crosses, barrows of 90 days of age, were allotted to the same outdoor rearing and feeding conditions. Live weight was recorded and average daily gain (ADG) was calculated. At slaughter (330-day-old) dressing and lean percentages were determined; backfat thickness and loin eye depth were measured. Carcasses were dissected into commercial cuts. Water holding capacity, pH and colour (45 min and 24 h post-mortem) were measured. Longissimus lumborum muscle samples were collected for cholesterol, \u3b1-tochopherol and intramuscular collagen (IMC) analyses. CT compared to DU and LW had the lowest growth rate and skeletal development. Casertana showed higher backfat thickness, lower lean cut/fatty cut ratio and less lean meat (P<0.05). Loin eye depth differed among genotypes with LW>DU>CT (P<0.05). CT showed higher red colour of the meat than DU and LW (P<0.05). CT compared to LW had the highest hydroxylysylpiridinoline (HLP) crosslink concentration and HLP/IMC ratio, and a lower IMC amount (P<0.05). Casertana pigs produced meat that could be tougher than that from the improved breed, but more acceptable from the technological point of view. At eleven months of age bone weight, length and diameter were clearly genetic type-related; differently, the bone maturit

Vibrational states and disorder in continuously compressed model glasses

We present in this paper a numerical study of the vibrational eigenvectors of a two-dimensional amorphous material, previously deeply studied from the point of view of mechanical properties and vibrational eigen-frequencies [7-10]. Attention is paid here to the connection between the mechanical properties of this material in term of elastic heterogeneities (EH), and how these inherent heterogeneous structures affect the vibrational eigenvectors and their plane waves decomposition. The systems are analysed for different hydrostatic pressures, and using results from previous studies, a deeper understanding of the boson peak scenario is obtained. The vibrational spectrum of a continuously densified silica glass is also studied, from which it appears that the pulsation associated with the boson peak follows the same pressure dependence trend than that of transverse waves with pulsation associated with the EH characteristic size.Comment: 9 pages, 12 figure

A re-examination of the life and work of A.F.G. Kerr and of his colleagues and friends

Arthur Francis George Kerr’s life is reviewed and related to a previously published account. Kerr’s collecting activity is analysed using an expanded version of the Thai Biogeography Group’s database of collections. 8,666 of the total 48,970 collections are Kerr’s and 3,178 are those of his colleagues and friends. Therefore, the total number of collections made by Kerr and his acquaintances is likely to be larger and more diverse than previously believed. Mapping of these data using GIS show that Kerr’s collecting activities focussed on particular regions of Thailand at particular times. Also large areas of the country remained unexplored by Kerr and his acquaintances: a pattern that, to some extent, persists to this day. The large, but dispersed, archive of Kerr’s photographs, maps, living collections and correspondence indicate that he was a skilled photographer (taking at least 3,000 images), cartographer (producing many hand-drawn maps) and exceptionally acute, accurate and detailed observer (fi lling numerous notebooks and leaving other records). It is clear that digitising these collections to form an on-line dedicated website is highly desirable to further progress on the fl ora of Thailand and surrounding countries and would form an unique record of the social history of early 20thC Thailand