Abstract The objective of this study was to compare the population, weight and honey production of honey bee (Apis mellifera) colonies fed with three different energy-protein diets based on a feed supplement made with brewer's yeast and pollen, in combination with 55% high fructose corn syrup (JMAF), or sucrose syrup (JA), or inverted sucrose syrup (JAI). Ninety colonies equalized in terms of population size, food stores and queen origin and age were used. All colonies were fed the protein supplement, but 30 of them were fed JMAF, 30 JA and 30 JAI. The adult bee population, capped brood area, weight and honey production of the colonies was determined at 27, 49 and 76 days after they were established and fed with the diets. Colonies fed JMAF were significantly heavier than those fed JA and JAI, between which there were no differences. JMAF-fed colonies produced significantly more honey (35.8 ± 3.35 kg) than those fed JA (28.2 ± 2.65) and JAI (24.8 ± 2.70 kg), between which there were no differences. These results suggest that the use of JMAF in combination with a protein supplement to stimulate honey bee colonies represents a more efficient option than the use of JAI and JAI with protein supplementation.

Resumen El objetivo del presente trabajo fue comparar el desarrollo poblacional, peso y producción de miel en colonias de abejas melíferas (Apis mellifera) alimentadas con tres dietas energético-proteicas a base de un suplemento elaborado con levadura de cerveza y polen, en combinación con jarabe de maíz de alta fructosa al 55% (JMAF), jarabe de sacarosa (JA), o jarabe de sacarosa invertido (JAI). Se utilizaron 90 colonias homogeneizadas en cuanto a tamaño poblacional, reservas de alimento y origen y edad de las reinas, todas alimentadas con el suplemento proteico, pero además, 30 de ellas recibieron JMAF, 30 JA y 30 JAI. La población de abejas adultas, área de cría operculada, peso y producción de miel de las colonias se determinó a los 27, 49 y 76 días después de haber sido establecidas y alimentadas con las dietas. Las colonias alimentadas con JMAF fueron significativamente más pesadas que las alimentadas con JA y JAI entre las cuales no hubo diferencias. Las colonias alimentadas con JMAF produjeron significativamente más miel (35.8±3.35 kg) que las alimentadas con JA (28.2±2.65) y con JAI (24.8±2.70 kg), entre las cuales no hubo diferencias. Los resultados sugieren que el uso de JMAF en combinación con un suplemento proteico en la alimentación artificial de las colonias de abejas melíferas estimula su crecimiento poblacional y la producción de miel, representando una opción más eficiente en comparación con las alimentadas con el suplemento proteico más el JA y JAI.

Abstract We analyze the influence of three combined effects on the contact resistance in organic- based thin film transistors: a) the active layer thickness, b) device architecture and c) semiconductor degradation. Transfer characteristics and parasitic series resistance were analyzed in devices with three different active layer thicknesses (50, 100 and 150 nm) using top contact (TC) and bottom contact (BC) thin film transistor (TFT) configurations. In both configurations, the lowest contact resistance (2.49 x 106 Ω) and the highest field-effect mobility (4.8 x 10-2 cm2/Vs) was presented in devices with the thicker pentacene film. Top contact thin film transistors presented field-effect mobility values one order of magnitude higher (4.8 x 10-2 cm2/Vs) than bottom contact ones (1 x 10-3 cm2/Vs). Threshold voltage for top-contact thin film transistors was -3.1 V. After 2 months, performance in the devices degraded and presented an increase of one order of magnitude (105 - 106 Ω) for BC-TFTs and two orders of magnitude (106 - 108 Ω) for TC-TFTs in contact resistance.

Mastitis is a expensive disease for dairy farming, the highest incidence occurs in the peripartum. The objective of this study was to determine the oxidative stress (OE) and antioxidant activity (AA) in the milk of cows with mastitis. Crossbred cows Holstein x Carora (n=30) were evaluated in the first 150 days of lactation, belonging to a commercial exploitation of Lara (Venezuela), divided into two groups of 15 animals each: control and one with subclinical mastitis (SM). Two milk samples were collected and stored in cryovials in liquid nitrogen. As OE indicators conjugated dienes (CD) were quantified using the Wallin and malondialdehyde (MDA) method by TBARS. The AA was evaluated by enzyme glutathione peroxidase (GSHPx) and glutathione (GSH) using a commercial kit. Data were analyzed by the “t” test. CD increased in the group with SM (1.41±0.12 nmol/mg protein) compared to the control group (0.59±0.08; p<0.001), as well as MDA (0.38±0.02 nmol/mg protein) compared to control (0.29±0.02, p<0.001) value. GSH-Px activity was elevated in the group with SM (40.75±5.09 mmol/min/ mL) compared with the control group (27.65±2.18, p<0.05). GSH concentration was increased in the group with SM (273.71±37.51 μmol/L) compared to the control group (150.00±21.17; p<0.05). It is concluded that subclinical mastitis in milk induces a state of OE, accompanied with an increase in antioxidant activity. These results support antioxidant supplementation during the peripartum period bovine

La mastitis es una patología costosa en la ganadería lechera, su mayor incidencia ocurre en el periparto. El objetivo del presente estudio fue determinar el estrés oxidativo (EO) y la actividad antioxidante (AA) en la leche de vacas con mastitis. Se evaluaron 30 vacas mestizas Holstein x Carora en los primeros 150 días de lactancia, pertenecientes a una explotación comercial del estado Lara (Venezuela) divididas en dos grupos, cada uno de 15 animales: uno control y el otro con mastitis subclínica (MS). Se les extrajo dos muestras de leche en crioviales almacenados en nitrógeno líquido y una en tubos de ensayo que se mantuvieron a 8°C. Como indicadores de EO se cuantificaron dienos conjugados (DC) por método de Wallin y malondialdehído (MDA) por test de sustancias reaccionantes con el ácido 2-tío barbitúrico). La AA derivada de la enzima glutatión peroxidasa (GSH-Px) y del glutatión (GSH), fue evaluada por kit comerciales. Para establecer la significación estadística de los resultados se utilizó la prueba “t” de Student exigiéndose un 95% de certeza (p<0,05). Se observó un incremento de DC en el grupo con MS (1,41±0,12 nmoles/mg proteínas) en relación al grupo control (0,59±0,08; p<0,001), como también de MDA (0,38±0,02 nmoles/mg proteínas) al comparar con el valor control (0,29 ±0,02; p<0,001). La actividad de la GSH-Px se encontró elevada en el grupo con MS (40,75±5,09 mmoles/min/ml) al comparar con el grupo control (27,65±2,18; p<0,05). La concentración de GSH se presentó aumentada en el grupo con MS (273,71±37,51 mmoles/l) en relación al grupo control (150,00±21,17; p<0,05). Se concluye que la mastitis subclínica induce en la leche un estado de EO, acompañado con un aumento de la actividad antioxidante. Estos resultados apoyarían la suplementación controlada con antioxidantes durante el período del periparto bovino

We present the analysis of a multi-epoch spectroscopic monitoring campaign of the O6Iefstar λ Cep. Previous observations reported the existence of two modes of non-radial pulsations in this star. Our data reveal a much more complex situation. The frequency content of the power spectrum considerably changes from one epoch to the other. We find no stable frequency that can unambiguously be attributed to pulsations. The epoch-dependence of the frequencies and variability patterns are similar to what is seen in the wind emission lines of this and other Oef stars, suggesting that both phenomena likely have the same, currently still unknown, origin.

Reportamos el análisis de una campaña de monitoreo espectroscópico multiépoca de la estrella O6 Ief λ Cep. Observaciones previas habían reportado la existencia de dos modos de pulsaciones no-radiales en esta estrella. Nuestros datos revelan una situación considerablemente más compleja. Las frequencias contenidas en el espectro de potencia cambian considerablemente de una época a otra. No encontramos ninguna frecuencia estable que pueda ser atribuida inequívocamente a pulsaciones. La dependencia temporal de las frequencias y los patrones devariabilidad son similares a los observados en las líneas de emisión del viento en esta y otras estrellas Oef, lo cual sugiere que ambos fenómenos tienen probablemente el mismo origen, aunque éste siga todavía sin conocerse.

Currents mediated by calcium-activated chloride channels (CaCCs), observed for the first time in Xenopus oocytes, have been recorded in many cells and tissues ranging from different types of neurons to epithelial and muscle cells. CaCCs play a role in the regulation of excitability in neurons including sensory receptors. In addition, they are crucial mediators of chloride movements in epithelial cells where their activity regulates electrolyte and fluid transport. The roles of CaCCs, particularly in epithelia, are briefly reviewed with emphasis on their function in secretory epithelia. The recent identification by three independent groups, using different strategies, of TMEM16A as the molecular counterpart of the CaCC is discussed. TMEM16A is part of a family that has 10 other members in mice. The discovery of the potential TMEM16 anion channel activity opens the way for the molecular investigation of the role of these anion channels in specific cells and in organ physiology and pathophysiology. The identification of TMEM16A protein as a CaCC chloride channel molecule represents a great triumph of scientific perseverance and ingenuity. The varied approaches used by the three independent research groups also augur well for the solidity of the discovery.

In the present study, histopathological analysis of rat mesentery was used to quantify the effect of two anti-inflammatory agents, dexamethasone (Dex) and pertussis toxin (Ptx), on leukocyte migration. The intravenous injection of Dex (1 mg/kg) and Ptx (1,200 ng) 1 h prior to the intraperitoneal injection of the inflammatory stimuli lipopolysaccharide (LPS) or formyl-methionyl-leucyl-phenylalanine (fMLP) significantly reduced the neutrophil diapedesis (LPS: Ptx = 0.86 ± 0.19 and Dex = 0.35 ± 0.13 vs saline (S) = 2.85 ± 0.59; fMLP: Ptx = 0.43 ± 0.09 and Dex 0.01 ± 0.01 vs S = 1.08 ± 0.15 neutrophil diapedesis/field) and infiltration (LPS: Ptx = 6.29 ± 1.4 and Dex = 3.06 ± 0.76 vs S = 15.94 ± 3.97; fMLP: Ptx = 3.85 ± 0.56 and Dex = 0.40 ± 0.16 vs S = 7.15 ± 1.17 neutrophils/field) induced by the two agonists in the rat mesentery. The inhibitory effect of Dex and Ptx was clearly visible in the fields nearest the venule (up to 200 µm), demonstrating that these anti-inflammatory agents act preferentially in the transmigration of neutrophils from the vascular lumen into the interstitial space, but not in cell movement in response to a haptotactic gradient. The mesentery of rats pretreated with Dex showed a decreased number of neutrophils within the venules (LPS: Dex = 1.50 ± 0.38 vs S = 4.20 ± 1.01; fMLP: Dex = 0.25 ± 0.11 vs S = 2.20 ± 0.34 neutrophils in the lumen/field), suggesting that this inhibitor may be acting at a step that precedes neutrophil arrival in the inflamed tissue. In contrast to that observed with Dex treatment, the number of neutrophils found in mesenteric venules was significantly elevated in animals pretreated with Ptx (LPS: Ptx = 9.85 ± 2.25 vs S = 4.20 ± 1.01; fMLP: Ptx = 4.66 ± 1.24 vs S = 2.20 ± 0.34 neutrophils in the lumen/field). This discrepancy shows that Ptx and Dex act via different mechanisms and suggests that Ptx prevents locomotion of neutrophils from the vascular lumen to the interstitial space. In conclusion, the method described here is useful for quantifying the inflammatory and anti-inflammatory effect of different substances. The advantage of this histopathological approach is that it provides additional information about the steps involved in leucocyte migration.