Influence of impurities in polygonization of fcc metals of low stacking fault energy

Several studies performed on metal polygonization [1-3] indicate that impurities lock the dislocations and prevent their motion during a thermal treatment of previously deformed crystals. Nevertheless, the study made on polygonization of Cu showed contradictory results. Young [4, 5] and Wei et al. [6] observed polygonization in OFHC Cu, but not in 99.999% Cu, and pointed out that polygonization in Cu is very slow and occurs upon prolonged annealing at temperatures near the melting point. Seeger and Schoeck [7, 8] suggested that, in metals of low stacking fault energy like Cu, Ag and Au, the dislocations would be extended into widely separated partials, and thus climbing would be difficult. The fact that polygonization has been observed [4, 5] in OFHC Cu, but not in 99.999% Cu, was explained by considering that impurities tend to allow the partial dislocations to recombine. More recently, French workers [9 - 13], showed that pure Cu polygonizes more easily than impure. In order to clarify the effect of impurities in climbing of the extended dislocations in fcc metals, and to find the effect of the stacking fault energy, the present study was carried out in Cu and Ag crystals.Laboratorio de Investigaciones de Metalurgia Físic

Maximum entropy niche-based modelling of seasonal changes in little bustard (Tetrax tetrax) distribution

P. 17-29The effects of habitat fragmentation on species may change seasonally mainly due to variations in resource availability and biotic interactions. In critical periods, such as winter, when the importance of intraspecific competition diminish, species may relax their environmental requirements widening their ecological niche to exploit the scarcer trophic resources more efficiently in comparison with spring. Those variations in niche width may implicate seasonal expansions/retractions in species distribution. In this sense, an integrated knowledge on the spatial arrangement of breeding and wintering suitable patches is essential to infer seasonal movements (migratory connectivity). This paper shows that little bustard environmental preferences were more predictable and complex (controlled by a larger number of environmental factors) in spring than in winter, when potential distribution and ecological niche width were slightly larger. In spring, habitat variables (i.e. percentage of dry crops and pasturelands and altitude) ruled species’ distribution; while, winter pattern was driven by mixed criteria, based on both habitat and climate (i.e. percentage of dry crops and wastelands and winter rainfall). Suitable patches were more connected across spatial scales in winter than in spring, i.e. landscape was perceived as less fragmented. The overlap between potential breeding and wintering distribution areas was high. In fact, most of the predicted wintering areas coincided or showed high connectedness with predicted breeding patches. Conversely, there were significant breeding patches that were predicted with low suitability, showing little connectedness with potential winter areas. Spring habitat was a better predictor of little bustard’s wintering range than vice versa, which has clear management implications (preserving breeding sites closer to wintering areas ensures the conservation of a larger proportion of the total distribution range). This is an example of how predictive large-scale modeling procedures can contribute to the optimization of land management aimed at species conservation.S

New data (U–Pb, K–Ar) on the geochronology of the alkaline-carbonatitic association of Fuerteventura, Canary Islands, Spain

Zircons from a nepheline-syenite of the Fuerteventura Basal Complex were dated by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The age obtained from a total of 21 U–Th–Pb analyses is 25.4F0.3 Ma (2r) indicating a late Oligocene–early Miocene crystallization. This age is consistent with new K–Ar ages on nepheline-syenites and pyroxenites, and contradicts previously published 39Ar–40Ar (feldspar) ages that were interpreted to represent a late Cretaceous–early Paleocene, pyroxenitic–syenitic magmatic episode. These new geochronological data are consistent with both field observations and most of the previously published ages on alkaline silicate rocks and associated carbonatites of Fuerteventura. Therefore, they strongly support the existence of a single, late Oligocene–early Miocene event of alkaline–carbonatitic magmatism in the Basal Complex of Fuerteventura, taking place at approximately 25 Ma and comprising: alkaline-pyroxenites, melteigites-ijolites, nepheline-syenites and carbonatites, as well as their volcanic equivalents and associated dykes. These new data provide an estimate for the length of time that it took the island to grow, thus eliminating one of the major problems in explaining its development by a hot-spot model

Fattening Commercial Zebu with Grazing and Low Supplementation on Small Farms.

The aim of this paper was to describe and group grazing commercial Zebu bulls, with low supplementation. Forty-four beef-producing farms from several cooperatives of credits and services were studied. Their members are private farmers from Sibanicu, Camaguey, Cuba. The farms were visited for three years,  and official records were made of each farmer for these variables: resources, animals, management, production, and economy. The main statigraph for the variables were calculated. The  average  initial weight, final weight, weight gain, and production per ha were, 202.6; 371.6; 501; and 326.2 kg, during 339.7 fattening days, respectively. The principal component  analysis (PCA) showed  a Kaiser-Meyer-Olkin coefficient higher than 0.66, and a significant Bartlett  sphericity  coefficient (P < 0.01), with self-values above 1. The two groups were made using a BIETAPIC cluster analysis

Efficacy of treatment for hyperglycemic crisis in elderly diabetic patients in a day hospital

The purpose of this prospective cohort study was to compare the costs of day hospital (DH) care for hyperglycemic crisis in elderly diabetic patients with those of conventional hospitalization (CH). Secondary objectives were to compare these two clinical scenarios in terms of glycemic control, number of emergency and outpatient visits, readmissions, hypoglycemic episodes, and nosocomial morbidity. The study population comprised diabetic patients aged >74 years consecutively admitted to a tertiary teaching hospital in Spain for hyperglycemic crisis (sustained hyperglycemia [>300 mg/dL] for at least 3 days with or without ketosis). The patients were assigned to DH or CH care according to time of admission and were followed for 6 months after discharge. Exclusion criteria were ketoacidosis, hyperosmolar crisis, hemodynamic instability, severe intercurrent illness, social deprivation, or Katz index >D. Sixty-four diabetic patients on DH care and 36 on CH care were included, with no differences in baseline characteristics. The average cost per patient was 1,345.1±793.6 € in the DH group and 2,212.4±982.5 € in the CH group (P <0.001). There were no differences in number of subjects with mild hypoglycemia during follow-up (45.3% DH versus 33.3% CH, P =0.24), nor in the percentage of patients achieving a glycated hemoglobin (HbA) <8% (67.2% DH versus 58.3% CH, P =0.375). Readmissions for hyperglycemic crisis and pressure ulcer rates were significantly higher in the CH group. DH care for hyperglycemic crises is more cost-effective than CH care, with a net saving of 1,418.4 € per case, lower number of readmissions and pressure ulcer rates, and similar short-term glycemic control and hypoglycemia rates

Petrología y geoquímica del magmatismo Jurásico-Cretácico vinculado a las mineralizaciones de Fe-Cu del cerro Pepita, SO del Chubut

Fe-Gu skarn arel hydrothermal deposils, al the Pepita Hill (&#39;Al Chubut Pruvince), are relat&oacute; to Jurassic-Cretaccous magmatism. Detailed petrographic studies arel Mole rock cieocliernical analyses perforrned on andesite fk-D.vs (Lago La Plata Fm) arad rhyol&iacute;tic-dacitic dikesand subvolcanic bodies (ElGato Fm) allowed tocharacterize the meta-aluminous to weakly per-aluminous, tholeiite-calc-alkaline signature, associated to a magrnaticarcsetting. The iron source of the El Abuelo ore deposit is possiblyrelated to the tholeiitic affinity of rocks from Lago La Plata Forrnation