Anaerobic co-digestion of solid slaughterhouse wastes with agro-residues : Synergistic and antagonistic interactions determined in batch digestion assays

Different mixture ratios of solid cattle slaughterhouse wastes (SB), manure (M), various crops (VC), and municipal solid wastes (MSW) were investigated for biogas production. The objective was to explore possible significant synergistic effects obtained from the combination of these different substrates. The performance of the process was assessed in thermophilic anaerobic batch co-digestion assays, using a four factor mixture design and methane yield (Y-CH4) and specific methane production rate (r(scH4)) as response variables. The highest methane yield, 655 NmL CH4/g VS was obtained when equal parts (ww) of SB, M, VC, and MSW were combined, while the combination of SB, M, and MSW resulted in the highest specific methane production rate (43 NmL CH4/g VS/d). A mixture design model was fitted to data in order to appraise synergistic and antagonistic interactions. Mixing all four substrates resulted in a 31% increase of the expected yield which was calculated from the methane potential of the individual fractions, clearly demonstrating a synergistic effect due to more balanced nutrient composition enhancing the anaerobic digestion process. However, no significant antagonistic effects were observed. In order to maximize both response variables simultaneously, a response surface method was employed to establish the optimal combination of substrate mixtures. The statistical results and analysis of the biological process gave a coherent picture of the results. (C) 2014 Elsevier B.V. All rights reserved

Epidemiological factors associated with the exposure of cattle to Coxiella burnetii in the Madrid region of Spain

2012 Elsevier Ltd. All rights reserved.;Domestic ruminants are considered to be the major source of Coxiella burnetii, the causative agent of Q fever. Even though Q fever is considered to be present worldwide, its distribution in many areas and countries remains unknown. Here, a serological assay was used to estimate the seroprevalence of C. burnetii in cattle in the Madrid region of Spain, to assess its spatial distribution, and to identify risk factors associated with positive results. Ten animals from each of 110 herds (n=1100) were randomly selected and analyzed using an ELISA test. In addition, epidemiological information, at both the herd and individual level, was collected. Variables for which an association with test results was detected in a bivariate analysis were included as predictors (main effects) in a multivariable logistic regression model. Herd and individual seroprevalences were 30% (95% CI=22.2-39.1) and 6.76% (95% CI=5.42-8.41), respectively, and a strong spatial dependence was identified at the first neighbour level using the Cuzick-Edwards test. Production type (dairy >beef >bullfighting) and age of animals (old vs. young) were the only variables significantly associated (P<0.05) with positive serological results at the herd and individual levels, respectively. These results indicate that cattle are exposed to C. burnetii in the Madrid region The high herd seroprevalence found in dairy herds (75%) indicates a higher risk of infection (probably for management reasons) whereas no C. burnetii positive bullfighting herds were identified.Depto. de Sanidad AnimalCentro de Vigilancia Sanitaria Veterinaria (VISAVET)Fac. de VeterinariaTRUEpu

¿Los de afuera?: Patrones cambiantes de exclusión en América Latina y el Caribe

En ¿Los de afuera? se plantean varios interrogantes fundamentales acerca de la naturaleza multidimensional e interrelacionada de la exclusión social, y se trasciende el énfasis tradicional en los resultados y los grupos para tratar el fenómeno como un proceso que se origina en características sociales que limitan los funcionamientos de los excluidos. En el informe se emplean las herramientas de la Economía experimental a fin de demostrar los enormes costos de la exclusión en términos de economía y bienestar, lo que indica que las políticas orientadas a la inclusión deberán verse como una inversión y no como una dádiva supuestamente generosa a quienes están en la peor situación social. Por ende, las políticas de este tipo no abarcan simplemente nuevos programas o nuevas instituciones para remediar las injusticias del pasado por medio de transferencias de ingresos, sino que implican cambios fundamentales en la manera en que se toman las decisiones, se asignan los recursos y se ponen en práctica las medidas de política en las sociedades democráticas.