Resumo O objetivo deste trabalho é descrever um caso de resistência mista, registrando pela primeira vez baixa eficácia antiparasitária contra Cooperia curticei em um rebanho de ovinos na província de Salta. O trabalho foi realizado em um estabelecimento da localidade de Cerrillos, província de Salta. Foram formados quatro grupos de 10 animais cada: um grupo controle, um grupo tratado com ivermectina, outro tratado com albendazol e outro tratado com levamisol. Os resultados de eficácia foram de 50,5% para ivermectina, 68,7% para albendazol e 99,2% para levamisol. Quanto à eficácia por gênero, foi de 42,8%, 64,8% e 97% em Haemonchus contortus, 100%, 79,2% e 99,3% para Trichostrongylus colubriformis e 88,5%, 100% e 100% para C. curticei para ivermectina, albendazol e levamisol respectivamente. Esse achado alerta para a situação da RA e deve ser considerada a ampla distribuição do uso dos diversos grupos químicos em estudo nos rebanhos da região.

Resumen El objetivo del presente trabajo es describir un caso de resistencia mixta, registrándose por primera vez baja eficacia antiparasitaria contra Cooperia curticei en una majada ovina en la provincia de Salta. El trabajo fue llevado a cabo en un establecimiento de la localidad de Cerrillos, provincia de Salta. Se conformaron 4 grupos de 10 animales cada uno, un grupo control, un grupo tratado con ivermectina, otro tratado con albendazol y otro tratado con levamisol. Los resultados de eficacia fueron de 50,5% para ivermectina, de 68,7% para albendazol y de 99,2% para levamisol. En cuanto a la eficacia por género, fue de 42,8%, 64,8% y 97% en Haemonchus contortus, de 100%, 70,2% y 99,3% para Trichostrongylus colubriformis y de 88,5%, 100% y 100% para C. curticei para ivermectina, albendazol y levamisol respectivamente. Este hallazgo alerta sobre la situación de RA y debe considerarse la amplia distribución del uso de varios grupos químicos en estudio en las majadas de la región.

Abstract The aim of this work is to describe a case of mixed resistance, finding for the first time low antiparasitic efficacy against Cooperia curticei in a sheep flock in the province of Salta. The work was carried out in an establishment in Cerrillos town, province of Salta. Four groups of 10 animals each were formed: a control group, a group treated with ivermectin, another treated with albendazole and another treated with levamisole. The efficacy results were 50.5% for ivermectin, 68.7% for albendazole, and 99.2% for levamisole. Regarding the efficacy by gender, it was 42.8%, 64.8% and 97% in Haemonchus contortus, 100%, 79.2% and 99.3% for Trichostrongylus colubriformis and 88.5%, 100 % and 100% for C. curticei for ivermectin, albendazole and levamisole respectively. This finding warns about the AR situation and of the wide distribution of the use of various chemical groups under study in the region's flocks, which should be considered.

Sintering is a thermal treatment normally used to produce parts from different types of powders, and it is a phenomenon that has been studied since the 1950's. Mechanisms and diffusion paths for several materials have already been established. However, the use of sintering; powders to repair fissures on solid materials has rarely been studied. The aim of this work is to study the solid state sintering of copper powders filling artificial grooves in a bar of solid copper. Sintering was carried out in an electrical furnace under H2 and Ar (10-90 respectively) atmosphere at two different temperatures, 1000 and 1050°C. The powder used to fill the grooves was a spherical atomized copper powder with a wide particle size distribution, 0-63/μm. Sintering of particles wat evaluated at the edge of the solid bar and at the center of the groove by scanning electron microscopy (SEM). It was observed that particles sintered well on the wall's surface at the site of the artificial groove. Greater densification reached by the smaller particles and higher sintering temperatures creates defects inside the groove. Those defects are the consequence of the constraints of sintering, and the necks developed during the thermal cycle could be broken by the higher stresses generated during densification.

El sinterizado libre es un tratamiento térmico usado para fabricar partes sótidas a partir de diferentes tipos de polvos. Este fenómeno se ha estudiado desde los años 50 y los mecanismos de difusión para diversos materiales son conocidos. Sin embargo, el sinterizado restringido ha recibido poca atención, a pesar de las aplicaciones que puede tener como la reparación de fisuras en materiales que no pueden ser soldados. El objetivo de este trabajo es estudiar el sinterizado restringido de polvos de cobre depositados al interior de una ranura creada artificialmente en barras sólidas de cobre. Se evaluó el efecto del tamaño de partícula y de la temperatura de sinterizado sobre la evolución microestructural. El sinterizado se llevó a cabo en un horno eléctrico a dos temperaturas, 1000 y 1500°C, bajo una atmósfera reductora de una mezcla de H2 y Ar (10-90 respectivamente). Los polvos usados son esféricos y con dos distribuciones de tamaño de partícula, 0-40 y 40-63 /μm. La evolución del sinterizado fue evaluada al borde de la barra sólida y al centro de la ranura mediante microscopia electrónica de barrido. Los resultados muestran que el método es capaz de reparar fisuras y que los contactos entre partículas y las paredes se desarrollan de manera satisfactoria. Sin embargo, se encontró que altas densificaciones generan esfuerzos suficientemente fuertes para romper los contactos creados entre partícula-pared y también entre partícula-partícula, generando defectos como grietas o delaminaciones al borde de la pared. Se encontró que el uso de partículas de menor tamaño es más perjudicial para la unión entre partículas y pared.

The present study had the objective of investigating the performance of broilers housed immediately after hatching or after a 12 or 24 hour of post-hatching holding time. One thousand and six hundred male Ross 308 broiler chicks with an initial body weight of 46 grams were used. These chicks were distributed in a completely randomized experimental design with 5 treatments and 8 replications of 35 birds in each treatment. The treatments in this study consisted of the removal of chicks from the hatchery in three different times: after 480, 492 and 504 hours of incubation. In each one of these times, 280 chicks were removed from the hatchery and immediately housed. Another group of an identical number of chicks of each time remained in the hatchery to be housed at 504 hours after hatching. The chick group corresponding to those hatched at 480 and 492 hours performed better until 7 days. However, no differences in body weight or body weight gain were observed at the end of the study. Feed efficiency, however was worse for the birds hatched and placed at 480 hours. There were no differences among treatments for mortality.

This study aimed to evaluate broiler responses to increases in feed energy (2,870, 3,000 and 3,100 kcal ME/kg) and the inclusion of Acidulated Soybean Soapstock (ASS) when compared to Degummed Soybean Oil (DSO) in feeds from placement to 7 days of age. From 7 to 42 days ASS or DSO were included in diets that contained similar energy and nutrient levels. Metabolizable energy values used to formulate the diets for ASS and DSO were 8,351 and 7,701 kcal ME/kg in the first week and 9,314 and 8,559 kcal ME/kg afterwards, respectively. Diets were based on corn and soybean meal and were fed to 1,600 one-d-old male broiler chicks randomly placed in 40 floor pens. No differences in performance due to fat source were seen at 7 days. However, the increase in energy levels to 3,100 kcal ME/kg reduced feed intake, whereas feed conversion was improved with energy at 3,000 kcal ME/kg. Live performance, and the yields of carcass and commercial cuts were not affected by the type of fat included in the feeds from 7 to 42 days, except for increased body weight at 21 and 35 days with ASS supplementation. Litter moisture at 7, 21, 35 and 42 days was not affected by any of the factors and there were no residual effects of treatments at 21, 35 and 42 days of age. On the other hand, body weight at 35 days was affected by the interaction of diets fed in the first week with those provided afterwards. The results showed that ME values used for DSO and ASS are adequate and that ASS may be used as fat source in broiler feeds from placement to 42 days of age.

Broiler chicks from one incubator hatch within long periods of time, which leads to dehydration and reduction in yolk sac reserves of those chicks that have hatched earlier and potentially impairs early performance. The present research investigated the hatching distribution at intervals of incubation using eggs of different weights within one breeder age or eggs from widely different breeder ages. Eggs from breeders at 27 and 59 weeks of age (54 and 69 g) and from breeders at 40 weeks of age, which were graded as light (58 g) and heavy (73 g), were placed in a commercial incubator. There were a total of 1,184 eggs distributed in four treatments and eight replicates: eggs from 27-week-old breeders (27B), eggs from 59-week-old breeders (59B), light eggs from 40-week-old breeders (40BL) and heavy eggs from 40-week-old breeders (40BH). Replicates were comprised of 37 eggs that were placed in each incubator tray. The treatments were physically separated from each other using a plate. Eggs were transferred to a hatcher after 432 hours of incubation and the first chick hatched at 449 hours of incubation. Afterwards, the number of completely hatched chicks from each replicate was recorded at six-hour intervals until 503 hours of incubation, when the hatchings stopped. Hatched chicks were removed from the trays after each measurement. Data were submitted to an analysis of variance with repeated measures. There was a significant interaction between breeder age and incubation length. The hatching onset of eggs from the old breeders was later compared to young breeders. Hatchability (%incubated eggs) was lower for the old breeders; however, differences in hatchability as a percentage of the hatched eggs were not so evident. Complete hatchability occurred only at 503 hours of incubation; however, more than 90% eggs had hatched 18 hours earlier.