Biogas will constitute a significant fraction of future power supply, since it is expected to contribute a large share of the EU renewable energy targets. Biogas, once produced, can be combusted in traditional boilers to provide heat, or to generate electricity. It can be used for the production of chemical compounds, or fed into a pipeline. This review paper will briefly analyze the current most promising emerging biogas technologies in the perspective of their potential uses, environmental benefits, and public acceptance; draw a picture of current conditions on the adoption of a biogas road map in the several EU Member States; analyze incentive and support policy implementation status and gaps; discuss non-technological barriers; and summarize proposed solutions to widen this energy's use.
Students from non-statistics degree programs often perceive statistics as a burden, underestimating its usefulness and encountering difficulties that cause them anxiety and stress, among others, which leads many of them to fail the course. Students’ attitudes can hinder their learning and development of useful skills associated with statistical thinking, which should be later applied outside the classroom. The aim of this study was to analyze students’ attitudes towards statistics in introductory courses in three schools of Argentina, grouped in Agricultural Sciences and Biological Sciences. We analyzed students’ attitudes at the beginning and at the end of the course, the differences between pre- and post-course attitudes and the relationship between these changes and students’ performances. The sample consisted of 436 students and their attitudes were measured using the Survey of Attitudes Towards Statistics (SATS-28), considering four components: Affect, Cognitive Competence, Value and Difficulty. Students’ performances were classified as: passed (and exempt from final exam), intermediate (but not exempt from final exam), and failed. Difficulty was not related to students’ performance, as opposed to what was detected with the other components. Cognitive competence was the only component that classified students’ performance in the correct order. Students who failed the course differed from the rest in that they developed more negative feelings towards statistics at the end of the course; in contrast, students with good performance showed an increase in the value given to statistics. Biological Sciences students presented higher average in the four components studied. Abstract: Spanish Los estudiantes de carreras universitarias no estadísticas a menudo perciben a estadística como una imposición, subestimando su utilidad, encontrando dificultades que les causan, entre otros, ansiedad y estrés y muchos desaprueban la materia. Las actitudes de los estudiantes pueden dificultar su aprendizaje y el desarrollo de habilidades útiles asociadas al pensamiento estadístico que deberían aplicarse posteriormente fuera del aula. El objetivo de este estudio fue analizar las actitudes de los estudiantes hacia la estadística en cursos introductorios en tres facultades de Argentina, agrupadas en Ciencias Agrícolas y Ciencias Biológicas. Analizamos sus actitudes al principio y al final del curso, las diferencias entre las actitudes posteriores y previas al curso y la relación entre estos cambios y el rendimiento del alumno. La muestra estaba compuesta por 436 estudiantes y sus actitudes se midieron utilizando la Encuesta de Actitudes Hacia la Estadística (SATS-28), considerando cuatro componentes: Afecto, Competencia Cognitiva, Valor y Dificultad. El rendimiento de los estudiantes se clasificó en promoción, intermedio y reprobación. Dificultad no se relacionó con el rendimiento del estudiante a diferencia con lo detectado con las otras componentes. La Competencia Cognitiva fue la única componente que clasificó el rendimiento en el orden correcto. Los estudiantes que reprobaron el curso se diferenciaron del resto en que desarrollaron más sentimientos negativos hacia la estadística al final del curso; en contraposición los que tuvieron un buen rendimiento, mostraron un aumento en el valor dado a la estadística. Los estudiantes de Ciencias Biológicas presentaron un promedio más alto en las cuatro componentes.
Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is distributed worldwide. BoHV-1 either alone or in association with other respiratory cattle pathogens causes significant economic losses to the livestock industry. The aim of this work was to validate a guinea pig model as an alternative method to the current BoHV-1 vaccine potency testing in calves. Guinea pigs were immunized with two doses of vaccine, 21 days apart and sampled at 30 days post vaccination (dpv). BoHV-1 antibody (Ab) response to vaccination in guinea pigs, measured by ELISA and virus neutralization (VN), was statistically compared to the Ab response in cattle. The guinea pig model showed a dose-response relationship to the BoVH-1 antigen concentration in the vaccine and it was able to discriminate among vaccines containing 1log(10) difference in its BoHV-1 concentration with very good repeatability and reproducibility (CV < or = 20%). A regression analysis of the Ab titers obtained in guinea pigs and bovines at 30 and 60dpv, respectively, allowed us to classify vaccines in three potency categories: "very satisfactory", "satisfactory" and "unsatisfactory". Bovines immunized with vaccines corresponding to each of these three categories were experimentally challenged with BoVH-1 virus, the level of protection, as measured by reduction of virus shedding and disease severity, correlated well with the vaccine category used. Data generated by 85 experiments, which included vaccination of calves and guinea pigs with 18 reference vaccines of known potency, 8 placebos and 18 commercial vaccines, was subjected to statistical analysis. Concordance analysis indicated almost perfect agreement between the model and the target species for Ab titers measured by ELISA and almost perfect to substantial agreement when Ab titers were measured by VN. Taken together these results indicate that the developed guinea pig model represents a novel and reliable tool to estimate batch-to-batch vaccine potency and to predict efficacy of killed BoHV-1 veterinary vaccines.
Morphological and physiological responses to freezing were evaluated in two ecotypes of the perennial turfgrass Paspalum vaginatum. Leaf extension rate, number of active meristems, leaf water potential and net photosynthesis were measured on plants of both a commercial cultivar, 'Sea Isle 2000', and a wild ecotype from the Flooding Pampa grasslands of Argentina. Plants were propagated by cloning, cultivated in pots, and examined during 18 consecutive days under two treatments: a non-frozen control treatment (15.5±7 ºC) and a frozen treatment with two stages: Stage 1 with four hours of freezing stress for 10 nights (-5ºC), and Stage 2 with 12 hours of freezing stress for eight nights (five nights at -5ºC and three nights at -8ºC). After these treatments, plants were returned to the outside environment to evaluate shoot injury and post-freezing recovery. Leaf water potential, net photosynthesis and leaf extension rate were significantly higher in the wild ecotype than in the commercial cultivar. Meristem density was reduced after freezing in both ecotypes, but was more pronounced in the commercial cultivar (98.5%) than in the wild ecotype (80%). Thus, the two ecotypes coming from different environments, exhibited different morphological and physiological responses to exposure to freezing temperatures.
Sixty-six fungi isolated from cyclamen phylloplanes were identified and assessed in vitro for antagonism to B. cinerea on leaves, petals, petioles and peduncles. The estimation of pathogen conidial production was used as indicator of biocontrol ability of each of the strains. They were classified by cluster analysis resulting in four categories according to their behavior in the different organs. The most promising category included 34 isolates that significantly reduced pathogen inoculum in all the organs. Correspondence analysis showed association among leaf isolations, strains of Clonostachys rosea and Penicillium spp. and the best biocontrol performance. The statistical analysis was successful in dealing with this complex set of experimental data. Leaf fungal diversity was higher than those of petals and petiols, with Shannon values of 2.7, 0.9 and 0.5 respectively. Evidence for antibiosis and hyperparasitism was found for C. rosea.
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