Kiwi forego vison in the guidance of their nocturnal activities

We propose that the Kiwi visual system has undergone adaptive regression evolution driven by the trade-off between the relatively low rate of gain of visual information that is possible at low light levels, and the metabolic costs of extracting that information

Excesso de peso em escolares de Florianópolis: um estudo de coorte retrospectivo sobre os padrões de crescimento e fatores associados

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Saúde Pública, Florianópolis, 2008.O objetivo do presente estudo foi avaliar a influência dos fatores preditores para excesso de peso em escolares de Florianópolis/SC. Foram avaliadas doze variáveis: IMC na coleta de dados, IMC materno e paterno, IMC aos 2 anos de idade, peso ao nascer, nível de atividade física, escolaridade materna e paterna, emprego da mãe, amamentação, renda familiar e tipo de locomoção da criança até a escola. Um modelo de regressão binária logística foi aplicado para determinar variáveis associadas com o IMC na faixa etária escolar de 7 a 10 anos, onde o modelo teórico preconizava as seguintes variáveis: IMC da mãe, atividade física da criança e renda familiar; a variável IMC do pai foi excluída apesar de apresentar um valor de p < 0,20 devido a grande número de perdas de indivíduos. O modelo final apresentou como fatores significantes o IMC da mãe - OR = 2,68 [IC95% 1,427; 5,039]; atividade física das crianças - OR = 1,705 [IC95% 0,660; 4,404]) e uma variável "proxy" que foi a renda familiar - OR = 1,188 [IC95% 0,499; 2,827] para até 2, 5 salários mínimos e OR = 1,118 [IC95% 0,530; 2,358] para 2, 5 - 5 salários mínimos. Esse modelo apresentou-se bem ajustado e foi capaz de identificar corretamente 98% das crianças sem excesso de peso. Os resultados encontrados neste estudo, apontam que crianças sem excesso de peso estiveram associadas a mães eutróficas ou com baixo peso, independente de outras variáveis analisadas. A atividade física não se apresentou estatisticamente significativa; a renda familiar também não foi significativa, porém melhorou o modelo final, mas não explica o excesso de peso em escolares. A escolaridade do pai e da mãe, amamentação, emprego da mãe, peso ao nascer e IMC da criança aos dois anos de idade, não foram apontadas como variáveis preditoras para o excesso e peso infantil, devendo outros estudos serem realizados para melhor caracterização dessa correlação.The goal of the present study is to evaluate the influence of predictive factors regarding weight excess amongst students in Florianópolis/SC. Twelve variables were evaluated: maternal and paternal BMI, BMI amongst the two years young, BMI by time of birth, physical activities level, maternal and paternal scholarship, mother's job, breast feeding, familiar budget and the means of locomotion used by the child to go to school. A model of logistic binary regression was applied to determine variables associated with the BMI amongst 7 to 10 years old students, where the theoretical model defined the following variables: BMI of the mother, physical activity of the children and family budget, the father's BMI variable was excluded despite presenting a value of p < 0,20 because a great number of individual losses. The final model presented as important factors the mother's BMI - OR = 2,68 [CI95% 0,499; 2,827]; physical activity of the children - OR = 1,705 [CI95% 0,660;4,404] and a "proxy" variable that was the family budget - OR = 1,188 [CI95% 0,499; 2,827] up to 2, 5 minimum wage and OR = 1,118[CI95% 0,530; 2,358] for 2, 5 - 5 minimum wage. This model presented itself well adjusted and was capable to correctly identify 98% of the children without weight excess. The results found on this study shows that children without excess weight were associated with mothers at normal or below normal weight, independently of the other evaluated variables. The physical activity did not presented to be statistically significant. The familiar budget was also not significant, however it improved the final model, but it does not explain the excess weight amongst students. The maternal and paternal scholarship, breast-feeding, mother's job, weight by time of birth and BMI amongst the two years young, were not pointed as predictive variables for children's weight excess, having other studies to be carried through for better characterization of this possible correlation

Start-up financing : how credit ratings and bank concentration impact credit access

Externe Kreditwürdigkeitsprüfungen durch Rating-Agenturen haben für Banken bei der Kreditvergabe an Unternehmen, aufgrund der verschärften Regulierung durch Basel II, erheblich an Bedeutung gewonnen. Die These, ungünstige oder fehlende Ratings seien der Grund dafür, dass insbesondere innovative, noch nicht etablierte Unternehmen ohne aussagekräftige Kredithistorie oft erhebliche Schwierigkeiten hätten, Bankkredite zu erhalten, bestätigt sich jedoch nicht. Eine Studie des Zentrums für Europäische Wirtschaftsforschung (ZEW) zeigt zwar, dass negative Ratings generell für Unternehmen den Zugang zu Krediten erschweren. Gerade für junge, innovative Unternehmen fällt dieser Effekt allerdings deutlich geringer aus als für andere

How do banks screen innovative firms? Evidence from start-up panel data

Start-up firms often face difficulties in raising external funds. Employing a unique panel dataset covering 9,715 start-up firms over the period 2007-2009, we find that high-tech startups are less likely to use bank finance and face more difficulties in raising bank finance than low-tech start-ups. We find that external credit scores do affect the availability of credit for start-up firms, but that banks rely less on external rating information in their decision making for high-tech start-ups than low-tech start-ups. Start-ups that have their main relation with a small bank use more bank finance and report less difficulties in getting credit. By contrast, a greater expertise of the bank in the firm’s industry is not associated with fewer difficulties to get bank loans. There are no differences between high-tech and low-tech start-ups regarding the impact of bank size

De la prevención a la promoción cultural: acciones pedagógicas en contextos de consumo problemático de drogas

La mejor forma de prevenir el abuso de las drogas es no ocuparse de las drogas en sí, sino de todo lo demás: el hueco social en que la droga se instala señalando con su presencia otras carencias. Este corrimiento conceptual, desde la droga hacia lo que subyace al consumo en la persona y su grupo social, es el punto de partida de la prevención como promoción, como elemento constitutivo de la educación social. Así, como educadores, es posible tomar distancia de la prevención y proponer acciones de promoción de conductas saludables; de desarrollo de capacidades autónomas; de construcción de sentidos de pertenencia; de rescate de lazos de solidaridad. Alentando la participación con miras a producir cambios de comportamientos y hábitos que posibiliten un mejor nivel de vida. El problema no es sólo de los que consumen, sino que se requiere una lectura que exceda el marco de lo individual para referenciarlo en las condiciones sociohistóricas en las que el consumo se produce. Este trabajo pretende dar cuenta de una propuesta de acción pedagógica en el campo de la articulación educación no formal – educación formal, en tanto refiere a la capacitación docente en la temática de las problemáticas sociales, específicamente, del uso problemático de drogas. El trabajo toma como antecedente directo la práctica profesional que desarrollo en el tema y reflexiona críticamente sobre esa práctica e intenta mejorarla y superarla, elaborando un dispositivo integral en el abordaje de la temática, desde la mirada de la Pedagogía Social. En este marco, presentamos una propuesta de acción pedagógica desarrollada desde la Dirección de Coordinación Institucional y Planificación de la Superintendencia de Investigaciones de Drogas Ilícitas del Ministerio de Justicia y Seguridad de la Provincia de Buenos Aires. No cabe duda de la importancia que tienen las grandes políticas que deben abordar esta problemática, pero tanto o más importantes son aquellos esfuerzos que se llevan a cabo día a día en las distintas instituciones, para evitar el desenganche de aquellos que están en relación con el uso problemático de drogas. Se torna ineludible, una mirada que asuma la necesidad y la especificidad de la acción pedagógica en esta problemática y la torne relevante en contextos educativos. Docentes, agentes escolares y extraescolares, construyen cotidianamente acciones como pueden y hasta donde les resulta posible, abriéndose paso entre el mandato redentor y la opción de no ver.Facultad de Humanidades y Ciencias de la Educació

Forest active restoration for silvopastoral use in Northwestern Patagonia: relative importance of the nurse effect

Ecological interactions, such as facilitation among plant species, has been identified as key for restoration actions. The stress-gradient hypothesis predicts that facilitation increases under harsh environments, but disturbance type and nurse shrub characteristics may modify this prediction. We aim at assessing the effect of two interacting factors (herbivory pressure and light availability) and palatability of the nurse shrub on the importance of nurse effect for active restoration of mixed evergreen forests of northern Patagonia (Argentina) for silvopastoral use. We planted Austrocedrus chilensis seedlings under two silvopastoral use intensities (higher and lower according to livestock seasonal movements) and under three micro-site treatments (palatable shrub, non-palatable shrub, inter-canopy), and evaluated survival and growth during three consecutive years. Under higher use intensity (increasing stress of light availability as desiccation risk and herbivory) we found contrasting effects of the nurse effect on seedling survival and growth, but the palatability of nurse shrub had no effect. Under higher use intensity, seedling survival was lower, while growth was higher. Higher values of seedling survival were found under low use intensity inter-canopy micro-site. Under high use, the presence of a nurse shrub is important for summer seedling survival, indicating its role in avoiding desiccation. The same occurred for winter seedling survival, where a nurse shrub may decrease mainly trampling risk. We highlight the importance of considering the interaction between disturbance factors for the net outcome of the nurse effect in active restoration actions, as it may allow for diverse actions to restoration.Fil: Chillo, María Verónica. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Amoroso, Mariano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Arpigiani, Daniela Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Rezzano, Carlos Abraham. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentin

Evidence for an Auditory Fovea in the New Zealand Kiwi (Apteryx mantelli)

Kiwi are rare and strictly protected birds of iconic status in New Zealand. Yet, perhaps due to their unusual, nocturnal lifestyle, surprisingly little is known about their behaviour or physiology. In the present study, we exploited known correlations between morphology and physiology in the avian inner ear and brainstem to predict the frequency range of best hearing in the North Island brown kiwi. The mechanosensitive hair bundles of the sensory hair cells in the basilar papilla showed the typical change from tall bundles with few stereovilli to short bundles with many stereovilli along the apical-to-basal tonotopic axis. In contrast to most birds, however, the change was considerably less in the basal half of the epithelium. Dendritic lengths in the brainstem nucleus laminaris also showed the typical change along the tonotopic axis. However, as in the basilar papilla, the change was much less pronounced in the presumed high-frequency regions. Together, these morphological data suggest a fovea-like overrepresentation of a narrow high-frequency band in kiwi. Based on known correlations of hair-cell microanatomy and physiological responses in other birds, a specific prediction for the frequency representation along the basilar papilla of the kiwi was derived. The predicted overrepresentation of approximately 4-6 kHz matches potentially salient frequency bands of kiwi vocalisations and may thus be an adaptation to a nocturnal lifestyle in which auditory communication plays a dominant role

How does the silvopastoral use modify the structure and population dynamics of mixed cypress and coihue forests?

Los bosques mixtos de ciprés de la cordillera (Austrocedrus chilensis) y coihue (Nothofagus dombeyi) del noroeste de la Patagonia están influenciados por fuertes presiones antrópicas como el uso silvopastoril, y en los cuales no existe una planificación sostenible. Los efectos de esta actividad son diversos y pueden producir impactos negativos a través de cambios en la composición y la dinámica del ecosistema. El objetivo fue caracterizar la estructura y composición de la comunidad vegetal de dosel y del sotobosque en bosques mixtos de ciprés y coihue bajo diferentes intensidades de uso silvopastoril, para inferir el impacto de ésta actividad sobre la dinámica poblacional del bosque. Se trabajó en tres establecimientos ganaderos con bosque bajo dos niveles de uso silvopastoril en un diseño de muestreo apareado. La comunidad del sotobosque fue afectada por la intensidad de uso, mostrando una mayor heterogeneidad y complejidad de la vegetación en zonas con alta intensidad, y una modificación en la arquitectura de los renovales de las principales especies del dosel por la mayor severidad del ramoneo. Estos cambios en el sotobosque potencialmente pueden generar cambios en los patrones de desarrollo de los renovales. Sin embargo, la intensidad de uso no tuvo un efecto significativo sobre la estructura demográfica de las poblaciones para las principales especies forestales, indicando que los establecimientos estudiados y la intensidad de uso silvopastoril no afectarían de manera diferencial la dinámica de la comunidad vegetal de dosel forestal.The mixed cypress (Austrocedrus chilensis) and coihue (Nothofagus dombeyi) forests of northwestern Patagonia are influenced by strong anthropic pressures such as silvopastoral, where sustainable management were not applied. The effects of this activity are diverse and can result in negative impacts through changes in the composition and dynamics of the plant community. The objective was to characterize the structure and composition of the canopy and understory vegetation of mixed cypress and coihue forests, under different intensities of silvopastoral use, to infer the impact of this activity on the population dynamics. We worked in three farms with livestock activity with forests under two use intensity levels (high and low) in a paired sampling design. The understory community was affected by the intensity of use, showing greater heterogeneity and complexity of the vegetation in areas of high intensity use and a modification in the architecture of the seedlings of the main canopy species due to the greater browsing severity. The changes found in the understory have the potential to cause changes in the developmental patterns of regeneration. However, the use intensity did not have a significant effect on the demographic structure of the populations of the major species indicating the studied farms and the different intensities of silvopastoral use that result, would not affect in a differential way the dynamics of the canopy community.Fil: Amoroso, Mariano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Chillo, María Verónica. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Alcalá, V. M.. Universidad del Aconcagua; ArgentinaFil: Rezzano, Carlos Abraham. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Arpigiani, Daniela Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Villacide, Ezequiel Martin. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentin

Solid state hydrogen storage in alanates and alanate-based compounds: a review

The safest way to store hydrogen is in solid form, physically entrapped in molecular form in highly porous materials, or chemically bound in atomic form in hydrides. Among the different families of these compounds, alkaline and alkaline earth metals alumino-hydrides (alanates) have been regarded as promising storing media and have been extensively studied since 1997, when Bogdanovic and Schwickardi reported that Ti-doped sodium alanate could be reversibly dehydrogenated under moderate conditions. In this review, the preparative methods; the crystal structure; the physico-chemical and hydrogen absorption-desorption properties of the alanates of Li, Na, K, Ca, Mg, Y, Eu, and Sr; and of some of the most interesting multi-cation alanates will be summarized and discussed. The most promising alanate-based reactive hydride composite (RHC) systems developed in the last few years will also be described and commented on concerning their hydrogen absorption and desorption performanc

CO2 reactivity with Mg2NiH4 synthesized by: In situ monitoring of mechanical milling

CO2 capture and conversion are a key research field for the transition towards an economy only based on renewable energy sources. In this regard, hydride materials are a potential option for CO2 methanation since they can provide hydrogen and act as a catalytic species. In this work, Mg2NiH4 complex hydride is synthesized by in situ monitoring of mechanical milling under a hydrogen atmosphere from a 2MgH2:Ni stoichiometric mixture. Temperature and pressure evolution is monitored, and the material is characterized, during milling in situ, thus providing a good insight into the synthesis process. The cubic polymorph of Mg2NiH4 (S.G. Fm3m) starts to be formed in the early beginning of the mechanical treatment due to the mechanical stress induced by the milling process. Then, after 25 hours of milling, Mg2NiH4 with a monoclinic (S.G. C12/c1) structure appears. The formation of the monoclinic polymorph is most likely related to the stress release that follows the continuous refinement of the material's microstructure. At the end of the milling process, after 60 hours, the as-milled material is composed of 90.8 wt% cubic Mg2NiH4, 5.7 wt% monoclinic Mg2NiH4, and 3.5 wt% remnant Ni. The as-milled Mg2NiH4 shows high reactivity for CO2 conversion into CH4. Under static conditions at 400 °C for 5 hours, the interactions between as-milled Mg2NiH4 and CO2 result in total CO2 consumption and in the formation of the catalytic system Ni-MgNi2-Mg2Ni/MgO. Experimental evidence and thermodynamic equilibrium calculations suggest that the global methanation mechanism takes place through the adsorption of C and the direct solid gasification towards CH4 formation.Fil: Grasso, María Laura. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada CAB. Departamento Fisicoquímica de Materiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Puszkiel, Julián Atilio. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada CAB. Departamento Fisicoquímica de Materiales; Argentina. Helmholtz-Zentrum Geesthacht GmbH; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Gennari, Fabiana Cristina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada CAB. Departamento Fisicoquímica de Materiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Santoru, Antonio. Helmholtz-Zentrum Geesthacht GmbH; AlemaniaFil: Dornheim, Martin. Helmholtz-Zentrum Geesthacht GmbH; AlemaniaFil: Pistidda, Claudio. Helmholtz-Zentrum Geesthacht GmbH; Alemani