Tricofagia en chinchillas (chinchilla lanígera): un problema de bienestar animal

Las estereotipias son desórdenes conductuales que se desarrollan en los animales como consecuencia de ambientes sub-óptimos, sobre los cuales no tienen control. Al estar asociadas con problemas de manejo que afectan el bienestar de los animales, y muchas veces resultar en un deterioro del fitness del animal estas pueden ser utilizadas como un indicador directo (basado en el animal) de bienestar animal. En el caso de la chinchilla la conducta de tricofagia (chinchillas come-pelo) ha sido asociada con problemas de manejo cuando estas son mantenidas en criaderos con fines comerciales y algunos factores individuales. A pesar de que se le ha dado menos atención en los estudios de estereotipias a la chinchilla, es importante su estudio ya que aún existe un importante número de criaderos de esta especie con fines peleteros, y la conducta de tricofagia no sólo afecta el bienestar del individuo, si no que además afecta su producto principal, la piel, por lo que es una patología conductual de importancia económica para el productor. El objetivo de la presente revisión es dar a conocer algunos posibles factores causales de la conducta de tricofagia en chinchillas y las implicancias de las estereotipias sobre el bienestar animal

Estimate of control voltage tolerances for a photo-electron analyzer of toroidal design

Sem informaçãoWe have run electron optics simulations and determined the tolerance in the control voltages of all elements (retarding input lens, analyzer, accelerating exit lens) of the La Trobe University photoelectron analyzer, recently redesigned to reach a spectral resolution of 5000, and which will be installed at LNLS (Campinas Brasil) and BESSY II (Berlin, Germany).We have run electron optics simulations and determined the tolerance in the control voltages of all elements (retarding input lens, analyzer, accelerating exit lens) of the La Trobe University photoelectron analyzer, recently redesigned to reach a spectral resolution of 5000, and which will be installed at LNLS (Campinas Brasil) and BESSY II (Berlin, Germany).We have run electron optics simulations and determined the tolerance in the control voltages of all elements (retarding input lens, analyzer, accelerating exit lens) of the La Trobe University photoelectron analyzer, recently redesigned to reach a spectral resolution of 5000, and which will be installed at LNLS (Campinas Brasil) and BESSY II (Berlin, Germany).334788791Sem informaçãoSem informaçãoSem informaçã

Quasi free-standing epitaxial graphene fabrication on 3C-SiC/Si(111)

© 2018 IOP Publishing Ltd. Growing graphene on SiC thin films on Si is a cheaper alternative to the growth on bulk SiC, and for this reason it has been recently intensively investigated. Here we study the effect of hydrogen intercalation on epitaxial graphene obtained by high temperature annealing on 3C-SiC/Si(111) in ultra-high vacuum. By using a combination of core-level photoelectron spectroscopy, low energy electron diffraction, and near-edge x-ray absorption fine structure (NEXAFS) we find that hydrogen saturates the Si atoms at the topmost layer of the substrate, leading to free-standing graphene on 3C-SiC/Si(111). The intercalated hydrogen fully desorbs after heating the sample at 850 °C and the buffer layer appears again, similar to what has been reported for bulk SiC. However, the NEXAFS analysis sheds new light on the effect of hydrogen intercalation, showing an improvement of graphene's flatness after annealing in atomic H at 600 °C. These results provide new insight into free-standing graphene fabrication on SiC/Si thin films

Effect of Methionine Supplementation During Late Gestation in Beef Females

Some amino acids are known to be essential to cattle and effect protein availability to the animal, especially during gestation when nutrient requirements are higher. Methionine is found to be one of the most limiting in low quality forage diets. Two 3-yr studies were performed to evaluate the impact of methionine supplementation during late gestation on intake, body weight, average daily gain, and subsequent calf performance in primiparous and multiparous females. In exp 1, 120 artificially inseminated pregnancy heifers were placed in a Calan gate feeding system (n=40/yr) and assigned 1 of 3 treatments during late gestation and fed ad libitum grass hay with either: no supllement, 2 lbs. distillers based supplement with 1 oz of rumen protected methionine. In exp 2, multiparous cows on upland winter range were fed 1 of 5 treatments; no supplement, ad libitum meadow hay, 1 lb. of a distiller\u27s based cube, 2 lb. of a distiller\u27s based cube, or 2 lb. of a distiller\u27s based cube plus 1 oz of a rumen protected methionine. Body weight, body condition score, reproductive responses, and subequent calf performance were recorded in both studies. No differences were observed in calving performance or progeny carcass characteristics in either experiment in response to methionine supplementation, so it may not be a necessary supplementation strategy

A graphene field-effect transistor as a molecule-specific probe of DNA nucleobases

© 2015 Macmillan Publishers Limited. All rights reserved. Fast and reliable DNA sequencing is a long-standing target in biomedical research. Recent advances in graphene-based electrical sensors have demonstrated their unprecedented sensitivity to adsorbed molecules, which holds great promise for label-free DNA sequencing technology. To date, the proposed sequencing approaches rely on the ability of graphene electric devices to probe molecular-specific interactions with a graphene surface. Here we experimentally demonstrate the use of graphene field-effect transistors (GFETs) as probes of the presence of a layer of individual DNA nucleobases adsorbed on the graphene surface. We show that GFETs are able to measure distinct coverage-dependent conductance signatures upon adsorption of the four different DNA nucleobases; a result that can be attributed to the formation of an interface dipole field. Comparison between experimental GFET results and synchrotron-based material analysis allowed prediction of the ultimate device sensitivity, and assessment of the feasibility of single nucleobase sensing with graphene

Molecular nitrogen acceptors in ZnO nanowires induced by nitrogen plasma annealing

©2015 American Physical Society. X-ray absorption near-edge spectroscopy, photoluminescence, cathodoluminescence, and Raman spectroscopy have been used to investigate the chemical states of nitrogen dopants in ZnO nanowires. It is found that nitrogen exists in multiple states: NO,NZn, and loosely bound N2 molecule. The results establish a direct link between a donor-acceptor pair emission at 3.232 eV and the concentration of loosely bound N2. This work confirms that N2 at Zn site is a potential candidate for producing a shallow acceptor state in N-doped ZnO as theoretically predicted by Lambrecht and Boonchun [Phys. Rev. B 87, 195207 (2013)10.1103/PhysRevB.87.195207]. Additionally, shallow acceptor states arising from NO complexes have been ruled out in this paper