The use of renewable energy sources is growing worldwide and the search for alternative biomass for the production of fuel, such as ethanol, has intensified. The aim of this study was to evaluate the effect of different nitrogen (N) rates on use efficiency and several attributes of the sugar and lignocellulosic biomass of four morphotypes (Hyb) of sorghum (Sorghum bicolor (L.) Moench). During two growing seasons, fermentable sugar yield (FSY), theoretical ethanol yield from fermentable sugar (EYsug), cellulosic ethanol yield (EYcel), and the nitrogen use efficiency (NUE) for dry matter yield (DMY) were evaluated. Significant year effects were observed for all measured traits. Nitrogen application strongly influenced all the traits measured, except soluble sugars (TSS). No significant N rate x morphotype interaction for any variable was noted. In both seasons sweet sorghum morphotypes were superior in FSY, due to higher values of soluble sugars (TSS). The 50 N rate presented the highest values in NUE. Although there were no significant differences between hybrids, the biomass yield of photosensitive types was decisive for ethanol yield prediction, both from sugars and cellulose.

El uso de fuentes de energía renovable está creciendo en el mundo y la búsqueda de biomasa alternativa para la producción de combustible, como el etanol, se ha intensificado. El objetivo de este trabajo fue estudiar el efecto de diferentes dosis de nitrógeno (N) sobre la eficiencia de uso y distintos atributos de la biomasa azucarada y lignocelulósica de cuatro morfotipos (Hib) de sorgo (Sorghum bicolor (L.) Moench). Durante dos campañas se evaluó el rendimiento de azúcar fermentable (RAF), rendimiento teórico de etanol a partir del jugo azucarado (REazu), rendimiento de etanol celulósico (REcel) y la eficiencia de uso de N (EUN) para la producción de materia seca (RMS). Se detectó significancia del efecto año en la mayoría de las variables. La aplicación de N influenció sobre todas las variables estudiadas, excepto azúcares solubles (SST). La interacción NxHib no influyó significativamente sobre ningún atributo. Los morfotipos sileros se destacaron para RAF, debido a mayores valores de SST. La dosis de 50 N presentó el valor más alto de EUN. Si bien no existieron diferencias significativas entre morfotipos, la productividad de biomasa en morfotipos fotosensitivos fue determinante en la predicción del rendimiento de etanol, tanto a partir de azúcares como celulosa.

We determined the effect of the opiate receptor antagonist naloxone on aggression, emotion, feeder control, and eating behavior in high and low aggression female pigeons maintained at 80% of their normal weight and exposed to food competition interactions. Pigeons were divided into pairs by previously ranked high aggression (total time spent in offensive aggression exceeding 60 s/5 min; N = 6 pairs) and low aggression females (time spent in offensive aggression less than 10 s/5 min; N = 6 pairs). A pigeon in each pair received an sc dose of naloxone (1 mg kg-1 ml saline-1) and the other animal received the vehicle. Trials (10 min) were performed 30 min after the naloxone/vehicle administration. The naloxone group of high aggression pigeons showed lower scores of total time spent in offensive aggression (control: 98.6 ± 12.0; naloxone: 46.8 ± 6.6 s; P < 0.05) and higher scores of time spent in emotional responses (control: 3.5 ± 0.6; naloxone: 10.8 ± 2.4 s; P < 0.05) than controls. The other behaviors scored, feeder control and eating behavior, were not affected in this group. The naloxone group of low aggression pigeons, however, showed higher scores of offensive aggression than their controls (5.3 ± 1.3; naloxone: 28.7 ± 8.0 s; P < 0.05). The present results suggest that opiate receptor mechanisms are implicated in offensive aggression responses in high and low aggression pigeons. However, as reported for brain 5-hydroxytryptamine manipulation and GABA-A-benzodiazepine receptor manipulation, the effect of the opiate receptor antagonist on food competition aggression in pigeons was related to their pretreatment level of aggression.