3,551 research outputs found
Improving stress coping ability: comparison between the CYP17 genotype Of Ovis Aries and Capra Hircus
The ability of animals to adapt to stress is not only an animal health and welfare concern, but also influences reproduction potential and robustness. An important pathway involved in the stress response is the hypothalamic-pituitary-adrenal axis (HPAA) that results in the release of cortisol from the adrenal gland. In this study the cortisol responses of South African Merinos were measured to assess HPAA responsiveness to stress and relate it to behavioural stress responses to
flock-isolation. The experiment was structured according to a 2×2 statistical design, with CYP17 genotype (WT1/WT1 vs. WT1/WT2) and selection line (H-line vs. L-line) as factors. Selection line criteria was based on divergent selection for (H-line) or against (L-line) maternal multiple rearing ability, where the H-line generally outperformed the L-line in terms of reproduction, animal
welfare and resistance to certain pathogens. The CYP17 genotype is involved in the biosynthesis pathway of cortisol. In the present study the CYP17 genotype showed a significant influence on behavioural stress responses, where three parameters of the flock-isolation test were affected (P<0.05), namely the number of bleats uttered, the urinating frequency and the average distance from a human operator. It is suggested that the CYP17 genotype affects behavioural responses via its effects on cortisol production, and that the SNPs located within the CYP17 genotype may have application in marker-assisted selection of sheep
The role of Cytochrome P450 17-alpha-Hydroxylase/ 17,20-Lyase (CYP17) in the stress coping ability in a divergently selected Merino sheep population
South African Merino sheep were selected divergently from the same base population for their ability to rear multiples. Two distinct populations were formed over a period of more than 20 years of selection. Reproduction (and therefore presumably fitness) in the line selected in the upward direction (H-line) was substantially improved compared to the line selected in the downward direction (L-line). In the present study, it was demonstrated that the H-line was more stresstolerant
than the L-line in terms of their glucose and cortisol response when challenged with insulin. Sheep from the breeding program were genotyped according to one of two cytochrome P450 17α-hydroxylase/17-20 lyase (CYP17) alleles, as these genotypes were previously linked to the ability of Angora goats to cope with external stressors. However, no association was found between CYP17 genotype and selection line. The difference in insulin induced stress response between the H- and the L-line can therefore not be attributed to CYP17 genotype
Three dimensional line stochastic matrices and extreme points
AbstractSeveral properties of the extreme points of the convex set of three dimensional line stochastic matrices of order n are presented. The existence of many different classes of extremal configurations is established. These extremal matrices exhibit a large variety of patterns with some unexpected configurations. Latin squares of special types are used in some of the existence results. Furthermore, three questions raised by Brualdi and Csima are answered concerning the extreme points of three dimensional plane stochastic matrices of order n
Adverbial hurdles in Dutch scrambling
This paper addresses the role of the adverb in Dutch direct object scrambling constructions. We report four experiments in which we investigate whether the structural position and the scope sensitivity of the adverb affect acceptability judgments of scrambling constructions and native speakers' tendency to scramble definite objects. We conclude that the type of adverb plays a key role in Dutch word ordering preferences
European air quality maps 2005 including uncertainty analysis
The objective of this report is (a) the updating and refinement of European air quality maps based on annual statistics of the 2005 observational data reported by EEA Member countries in 2006, and (b) the further improvement of the interpolation methodologies. The paper presents the results achieved and an uncertainty analysis of the interpolated maps and builds upon earlier reports from Horalék et al. (2005; 2007)
Intramolecular halogen-halogen bonds?
By analysing the properties of the electron density in the structurally simple perhalogenated ethanes, X3C–CY3 (X, Y = F, Cl), a previously overlooked non-covalent attraction between halogens attached to opposite carbon atoms is found. Quantum chemical calculations extrapolated towards the full solution of the Schrödinger equation reveal the complex nature of the interaction. When at least one of the halogens is a chlorine, the strength of the interaction is comparable to that of hydrogen bonds. Further analysis shows that the bond character is quite different from standard non-covalent halogen bonds and hydrogen bonds; no bond critical points are found between the halogens, and the σ-holes of the halogens are not utilised for bonding. Thus, the nature of the intramolecular halogen···halogen bonding studied here appears to be of an unusually strong van der Waals type.Peer reviewe
Origin of salinity variations in Florida Bay
This note presents a method of distinguishing the source of freshwater that causes reductions in salinity in the coastal environment of South Florida. This technique, which uses the 18O and D of the water, allows for differentiation of the freshwater derived from precipitation as opposed to runoff, because surface waters in the Everglades have been highly evaporated and therefore have elevated 18O and dD values relative to precipitation. A time series of monthly 18O and D values of surface waters, collected from stations in Florida Bay between 1993 and 1999, has shown that, during this time, the major source of freshwaters causing depressions in the salinity in the western portion of Florida Bay was derived from precipitation rather than from the runoff of water from the Everglades. In the eastern portion of Florida Bay, close to the boundary between peninsular Florida and the Bay, the proportion of freshwater derived from precipitation drops steadily, reaching \u3c10%. This method not only allows differentiation between the sources of freshwater but can, in a temporal sense, ascertain the effectiveness of water management practices on the salinity of the estuarine ecosystems of South Florida
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