Three-dimensional dispersion induced by extreme tensile strain in La_(2–x)Sr_xCuO_4 films

The electronic band structure probed by angle-resolved photoemission spectroscopy on thin epitaxial La2–xSrxCuO4 films under extreme tensile strain shows anomalous features compatible with c-axis dispersion. This result is in striking contrast with the usual quasi-two-dimensional (2D) dispersion observed up to now in most superconducting cuprates, including relaxed and compressively strained La2–xSrxCuO4 films grown under the same conditions. The data were analyzed using a 3D tight-binding dispersion for a body-centered-tetragonal lattice. We relate the enhancement of the c-axis dispersion to the significant displacement of the apical oxygen induced by epitaxial strain

The effects of dams on longitudinal variation in river food webs

We examined the effects of two dams on longitudinal variation of riverine food webs using stable isotope and gut contents analyses along four rivers in the Hunter Valley in eastern Australia. Longitudinal 15N enrichment was observed in most invertebrate taxa and food sources but significant longitudinal variation was rare for 13C, and composition of gut contents of invertebrate taxa did not vary significantly with longitudinal position. Most invertebrates and food sources were more 15N-enriched at sites immediately downstream of the dams than expected from their upstream longitudinal position, a result not mirrored by gut contents and 13C. Enrichment of 15N downstream may be attributed to altered water quality as a result of impoundment but further research is necessary to elucidate whether physico-chemical riverine processes or trophic mechanisms are responsible. Our observations regarding the influence of dams on isotope ratios are contrary to the few existing studies, suggesting the small volumes relative to annual inflows of dams in the present study limit downstream impacts by maintaining aspects of flow variability. © 2013 © 2013 Taylor & Francis

Experimental Electronic Structure and Interband Nesting in BaVS_3

The correlated 3d sulphide BaVS_3 is a most interesting compound because of the apparent coexistence of one-dimensional and three-dimensional properties. Our experiments explain this puzzle and shed new light on its electronic structure. High-resolution angle-resolved photoemission measurements in a 4eV wide range below the Fermi level explored the coexistence of weakly correlated a_1g wide-band and strongly correlated e_g narrow-band d-electrons that is responsible for the complicated behavior of this material. The most relevant result is the evidence for a_1g--e_g inter-band nesting condition.Comment: 4 pages, 3 figure

Manifestation of pseudogap in ab-plane optical characteristics

A model in which a gap forms in the renormalized electronic density of state (DOS) with missing states recovered just above the pseudogap $\Delta_{pg}$, is able to give a robust description of the striking, triangular like, peak seen in the real part of the optical self-energy of underdoped cuprates. We use this model to explore the effect of the pseudogap on the real part of the optical conductivity and on the partial sum rule associated with it. An important result is that the optical spectral weight redistributes over a much larger frequency window than it does in the DOS.Comment: 12 pages, 3 figures. Submitted to Journal of Physics: Condensed Matte

Comparative Studies on the Reproductive and Productive Traits of New Hampshire and Sombor Crested Chicken Breeds Reared in Semi-Extensive Production System

Research was conducted on New Hampshire (in further text NH) and Sombor Crested (in further text SC) breeds which were kept in semi extensive system. 56 birds of each breed were used (50 females and 6 males) in the experiment. 100 eggs from every chicken breed were used for natural hatching, and remained eggs were sold. From the total number of the naturally incubated eggs, 83 (NH) and 85 (SC) chickens were hatched, and they were used for the study of performance and related parameters. Eggs and chickens originating from NH breed were statistically significantly heavier (P<0.001; P<0.01) compared with SC breed. Egg shape index and chicken percentage in egg weight were significantly higher at SC (P<0.001; P<0.05) compared to NH breed. Very strong positive correlation was determined between egg weight and chicken weight in both breeds. Very weak negative correlation was determined between egg weight and relative chicken intake in the egg weight. Similarly, between egg shape index and chicken weight, negative correlation coefficient was determined in both breeds. However, between egg shape index and chicken percentage, statistically significant (P<0.001) negative correlation coefficient was determined in NH breed. Significant (P<0.05) positive correlation for the same performances was determined in SC breed

Possibilities of more efficient usage of genetic potential of broilers breeders

During the last ten years, poultry production in the world and particularly, EU has been specific due to new trends, whereby special attention is focused on regulations and procedures that are adopted by European Union (EU), Food and Agriculture Organization of the United Nations (FAO), International Organization for Standardization (ISO) and the World Trade Organization. Legal regulations in EU (standards, directions) are focused on all species and categories of poultry. Based on this, breeding of broiler (meat-type line strains) and production of hatching eggs and day old chickens (incubation) as well as other issues are the focus of this review. This paper presented results of studies carried out using different technological procedures in the breeding of broiler and production of one day old chickens. These showed a full expression of genetic potential of strains, along with preservation of poultry welfare

The influence of population density and duration of breeding on broiler chickens productivity and profitability

Fattening of broiler chickens is a very specific production process characterized by intensive production principles, rapid increase in broilers, small consumption of food/kg of gain (feed conversion ratio) and a large production of broilers&#8217; meat per square meter of surface. In order to increase the profitability of this production, the intention of farmers is to reduce the duration of production as well as to increase population density, with the aim of increasing the production of broiler chickens&#8217; meat,calculated per unit of surface (m2). However, most of the countries in the world, in order to protect and preserve the welfare of poultry, limit the maximum of broilers&#8217; meat production by regulations and standards. These researches aim to determine the optimal density and duration of fattening in a way to achieve the best production results and the profitability of fattening the broiler chickens hybrids Cobb 500 in temperate continental climate, while preserving the welfare of poultry. From six different population densities (16.84, 16.33, 14.29, 12.75, 14.80 and 15.46 birds per m2) and fattening period between 37 and 40 days, the best production and economic performance showed that a group ofchickens that was fattened in a period of 40 days had a population density of about 16 birds per m2. This group of broilers produced the most meat per m2 (about 33 kg), the welfare of poultry is maintained and the standard was not exceeded, so we can say that the best economy and profitability of fattening broiler chickens in the concerned region is achieved. In other groups of chickens, profitability could be more advantageous if the increased population density goes up to 16 birds perm2; or the duration of fattening could be extended up to 40 days and by this way the welfare of poultry would not be violated