349 research outputs found

    Assessment of Structural Traits and Management Related to Dairy Herds in the Peri-urban Area of Bobo Dioulasso (South West of Burkina Faso)

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    To define mean herd size, structural traits, animal sourcing and use, management and aspects related to the milk production, 118 dairy herds, involved in a FAO dairy development project were studied. The mean herd size after allocation to clusters: Small (≤38 heads), Medium (>38, ≤61 heads) and Large (>61 heads) was 52.8±25.8, ranging from 7 to 134 heads of cattle. The following genotypes: Cross bred (CR) 58.8%, Zebu (ZB) 23.2% and Taurine cattle (TA) 18.0% which were not uniformly distributed neither across nor within herds were identified. Sex ratio was two thirds of females (70.6%), one third of males (28.1%) and a low proportion (1.3%) of castrated males. No mature TA males compared to 53.3% of the male ZB and 31.4% of the male CR, were indicated as potential sires. Investments in purchase of animals were higher in Small than in Medium and Large herds; of all purchased sires 53.8% were found in Small herds vs. 28.2% and 18.0% in Medium and Large. Herd property was equally distributed between single (56.8%) and multi property (43.2%). There was more manpower available per 100 cows in Small, being almost double and triple than in Medium and Large herds. Although milk extracted, was similar in all clusters averaging 2.4±0.5 litres/day/cow, milk off take rate, due to higher proportion of lactating cows, appeared higher in Small herds

    Atomistic Simulations of P(NDI2OD-T2) Morphologies: From Single Chain to Condensed Phases

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    We investigate theoretically the structure, crystallinity, and solubility of a high-mobility n-type semiconducting copolymer, P(NDI2OD-T2), and we propose a set of new force field parameters. The force field is reparametrized against density functional theory (DFT) calculations, with the aim to reproduce the correct torsional angles that govern the polymer chain flexibility and morphology. We simulate P(NDI2OD-T2) oligomers in different environments, namely, in vacuo, in the bulk phase, and in liquid toluene and chloronaphthalene solution. The choice of these solvents is motivated by the fact that they induce different kinds of molecular preaggregates during the casting procedures, resulting in variable device performances. Our results are in good agreement with the available experimental data; the polymer bulk structure, in which the chains are quite planar, is correcly reproduced, yet the isolated chains are flexible enough to fold in vacuo. We also calculate the solubility of P(NDI2OD-T2) in toluene and chloronaphthalene, predicting a much better solubility of the polymer in the latter, also in accordance to experimental observations. Different morphologies and dynamics of the oligomers in the two solvents have been observed. The proposed parameters make it possible to obtain the description of P(NDI2OD-T2) in different environments and can serve as a basis for extensive studies of this polymer semiconductor, such as, for example, the dynamics of aggregation in solvent

    Epitaxial growth and thermodynamic stability of SrIrO3/SrTiO3 heterostructures

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    Obtaining high-quality thin films of 5d transition metal oxides is essential to explore the exotic semimetallic and topological phases predicted to arise from the combination of strong electron correlations and spin-orbit coupling. Here, we show that the transport properties of SrIrO3 thin films, grown by pulsed laser deposition, can be optimized by considering the effect of laser-induced modification of the SrIrO3 target surface. We further demonstrate that bare SrIrO3 thin films are subject to degradation in air and are highly sensitive to lithographic processing. A crystalline SrTiO3 cap layer deposited in-situ is effective in preserving the film quality, allowing us to measure metallic transport behavior in films with thicknesses down to 4 unit cells. In addition, the SrTiO3 encapsulation enables the fabrication of devices such as Hall bars without altering the film properties, allowing precise (magneto)transport measurements on micro- and nanoscale devices.Comment: 5 pages, 3 figure

    Fundamentals of tin iodide perovskites:A promising route to highly efficient, lead-free solar cells

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    Hybrid tin-iodide perovskites are investigated as potential lead-free replacement of the lead-iodide perovskites; however, the intrinsic operational limit of these systems has not been described in detail, so far. In this work we combine advanced ab initio calculations with XRD and absorption measurements to lay out the fundamentals of formamidinium (FASnI3) and methylammonium (MASnI3) tin iodide perovskites, in comparison with the lead-halide MAPbI3 prototype. Our theoretical analysis reveals that the tin-based materials display an intrinsic photoconversion efficiency on a par with the lead perovskites, and even superior in the thick-layer limit, where the theoretical PCE reaches 30.5% for lead-halides, and 32.3% for tin-halides under AM1.5G illumination; this is the result of two competing factors: a smaller absorption cross section at the onset for stannates, and their smaller band gap of 1.36 eV, thus very close to the ideal Shockley-Queisser limit. We found the rate of photoluminescence emission extremely sensitive to the absorption spectral weight at the band extrema, resulting in B-factor as different as 7.6 × 10-9 s-1 cm3 for MASnI3 and 0.4 × 10-10 s-1 cm3 for FASnI3. The additional impact of Urbach energy and hole doping, giving rise to large Burstein-Moss effect, is described in detail. This journal i

    Systematic revision of the granulatus group of urophonius pocock, 1893 (Scorpiones, Bothriuridae), with description of a new species from central Chile

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    A systematic revision of the granulatus group of the bothriurid scorpion genus Urophonius Pocock, 1893 is presented. Urophonius pizarroi, n. sp., a new species from central Chile, is described. Urophonius granulatus Pocock, 1898, Urophonius somuncura Acosta, 2003, and Urophonius tregualemuensis Cekalovic, 1981, are redescribed using modern standards. The adult males of U. somuncura and U. tregualemuensis are described for the first time. A distribution map and key to the species of the granulatus group are provided, along with a discussion of their phenology.Fil: Ojanguren Affilastro, Andres Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Ochoa, José A.. Universidade de Sao Paulo; Brasil. American Museum of Natural History; Estados UnidosFil: Mattoni, Camilo Ivan. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Prendini, Lorenzo. American Museum of Natural History; Estados Unido

    Prevention of Breast cancer with tamoxifen:preliminary findings from the italian randomised trial among hysterectomised women

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    Prevention of breast cancer with tamoxifen: preliminary findings from the Italian randomised trial among hysterectomised women. Italian Tamoxifen Prevention Study. Veronesi U, Maisonneuve P, Costa A, Sacchini V, Maltoni C, Robertson C, Rotmensz N, Boyle P. SourceEuropean Institute of Oncology, Milan, Italy. Abstract BACKGROUND: Tamoxifen is a candidate chemopreventive agent in breast cancer, although the drug may be associated with the development of endometrial cancer. Therefore we did a trial in hysterectomised women of tamoxifen as a chemopreventive. METHODS: In October, 1992, we started a double-blind placebo-controlled, randomised trial of tamoxifen in women (mainly in Italy) who did not have breast cancer and who had had a hysterectomy. Women were randomised to receive tamoxifen 20 mg per day or placebo, both orally for 5 years. The original plan was to follow the intervention phase by 5 years' follow-up. In June, 1997, the trialists and the data-monitoring committee decided to end recruitment primarily because of the number of women dropping out of the study. Recruitment ended on July 11, 1997, and the study will continue as planned. The primary endpoints are the occurrence of and deaths from breast cancer. This preliminary interim analysis is based on intention-to-treat. FINDINGS: 5408 women were randomised; participating women have a median follow-up of 46 months for major endpoints. 41 cases of breast cancer occurred so far; there have been no deaths from breast cancer. There is no difference in breast-cancer frequency between the placebo (22 cases) and tamoxifen (19) arms. There is a statistically significant reduction of breast cancer among women receiving tamoxifen who also used hormone-replacement therapy during the trial: among 390 women on such therapy and allocated to placebo, we found eight cases of breast cancer compared with one case among 362 women allocated to tamoxifen. Compared with the placebo group, there was a significantly increased risk of vascular events and hypertriglyceridaemia among women on tamoxifen. INTERPRETATION: Although this preliminary analysis has low power, in this cohort of women at low-to-normal risk of breast cancer, the postulated protective effects of tamoxifen are not yet apparent. Women using hormone-replacement therapy appear to have benefited from use of tamoxifen. There were no deaths from breast cancer recorded in women in the study. It is essential to continue follow-up to quantify the long-term risks and benefits of tamoxifen therapy

    Revision of Orobothriurus Maury, 1976.

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    90 p. : ill. (some col.), maps ; 26 cm.The systematics of the Andean scorpion genus, Orobothriurus Maury, 1976 (Bothriuridae Simon, 1880), is revised. New locality records, obtained during recent field expeditions, distribution maps, and a key to identification of the 15 known species, are provided. Six new species are described: Orobothriurus calchaqui, n. sp., from northwestern Argentina; Orobothriurus compagnuccii, n. sp., from the central Andes of Argentina; Orobothriurus huascaran, n. sp., from central Peru; Orobothriurus quewerukana, n. sp., from southern Peru and northern Chile; Orobothriurus ramirezi, n. sp., from central Chile; and Orobothriurus tamarugal, n. sp., from northern Chile. The known distribution of Orobothriurus and the altitude record for scorpions are discussed. The world's altitude record for a scorpion, previously reported as 5550 m, is demonstrated to be 4910 m

    Urophonius granulatus group.

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    40 p. : ill., map ; 26 cm. "August 23, 2010."A systematic revision of the granulatus group of the bothriurid scorpion genus Urophonius Pocock, 1893 is presented. Urophonius pizarroi, n. sp., a new species from central Chile, is described. Urophonius granulatus Pocock, 1898, Urophonius somuncura Acosta, 2003, and Urophonius tregualemuensis Cekalovic, 1981, are redescribed using modern standards. The adult males of U. somuncura and U. tregualemuensis are described for the first time. A distribution map and key to the species of the granulatus group are provided, along with a discussion of their phenology

    Rumikiru, n. gen. (Scorpiones: Bothriuridae), a new scorpion genus from the Atacama Desert

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    Rumikiru, n. gen., a new bothriurid scorpion genus from the coastal Atacama Desert, Chile, is described. This is the first scorpion genus endemic to northern Chile. It is most closely related to Pachakutej Ochoa, 2004, from the inter-Andean valleys of Peru. Orobothriurus lourencoi Ojanguren-Affilastro, 2003, is transferred to the new genus and redescribed, creating Rumikiru lourencoi (Ojanguren-Affilastro, 2003), n. comb., and a second species of the genus, Rumikiru atacama, n. sp., is described.Fil: Ojanguren Affilastro, Andres Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Mattoni, Camilo Ivan. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ochoa, José A.. Universidade de Sao Paulo; Brasil. Universidad Nacional de San Antonio Abad del Cusco. Museo de Historia Natural; PerúFil: Prendini, Lorenzo. American Museum Of Natural History; Estados Unido
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