8 research outputs found
Tight-minimal dichotomies in Banach spaces
We extend the methods used by V. Ferenczi and Ch. Rosendal to obtain the
`third dichotomy' in the program of classification of Banach spaces up to
subspaces, in order to prove that a Banach space E with an admissible system of
blocks with admissible set A, contains an infinite dimensional subspace with a
basis which is either A-tight or A-minimal. In this setting we obtain, in
particular, dichotomies regarding subsequences of a basis, and as a corollary,
we show that every normalized basic sequence has a subsequence which either
satisfies a tightness property or is spreading. Other dichotomies between
notions of minimality and tightness are demonstrated, and the Ferenczi-Godefroy
interpretation of tightness in terms of Baire category is extended to this new
context.Comment: 42 page
Revisão das interações ecológicas da mosca Cochliomyia hominivorax e avaliação dos possíveis impactos ecológicos de sua erradicação no Uruguai
Controlling a pest species raises questions about the harmful effects its eradication could cause in ecosystems. Currently, in Uruguay are being analyzed strategies to eradicate the New World Screwworm (NWS), Cochliomyia hominivorax (Diptera: Calliphoridae), an obligatory ectoparasite that causes myiasis in warm-blooded vertebrates, including humans. The loss of a species implies a risk of secondary extinctions and cascading effects that depend on the ecological function of the species and the capacity of the rest of the species with which it interacts to compensate for its loss. To assess the ecological impact of the NWS eradication, we analyzed its ecological redundancy, its effect as an indirect regulatory agent for other species, and its participation in critical ecosystem functions. We conclude that the NWS presents high functional redundancy in most ecological interactions. It does not play an essential role as a regulatory agent of other species and does not play an important role in critical ecosystem functions. Without ignoring the information gaps that certainly exist about the ecological interactions network of the NWS in Uruguay, we estimate that its eradication is unlikely to cause secondary extinctions or cascading effects in the networks it integrates. In order to timely detect possible impacts during the course of the program, it is recommended to monitor the ecosystems using indicators related to direct and indirect partners in the ecological interactions of the NWS.El control de una especie plaga genera interrogantes sobre los efectos nocivos que su erradicación podría causar en los ecosistemas. Actualmente, en Uruguay se analizan estrategias para erradicar la mosca de la bichera (MB), Cochliomyia hominivorax (Diptera: Calliphoridae), un ectoparásito obligatorio que causa miasis en vertebrados de sangre caliente, incluidos los humanos. La pérdida de una especie supone un riesgo de extinciones secundarias y efectos en cascada que dependen de la función ecológica de la especie que se pierde y la capacidad del resto de las especies con las que interactúa para compensar su pérdida. Para evaluar el impacto ecológico de la erradicación de la MB analizamos su redundancia ecológica, su efecto como agente regulador indirecto de otras especies y su participación en funciones críticas de los ecosistemas. Concluimos que la MB presenta alta redundancia funcional en la mayoría de sus interacciones ecológicas, no juega un papel importante como agente regulador de otras especies y no juega un papel importante en funciones ecosistémicas críticas. Sin desconocer los vacíos de información que ciertamente existen sobre la red de interacciones ecológicas de la MB en Uruguay, estimamos que es poco probable que su erradicación cause extinciones secundarias o efectos en cascada en las redes de interacciones ecológicas que integra. A fin de detectar oportunamente eventuales impactos durante el curso del programa, se recomienda monitorear los ecosistemas utilizando indicadores relacionados con socios directos e indirectos en las interacciones ecológicas de la MB.O controle de uma espécie praga levanta questões sobre os efeitos nocivos que a erradicação pode causar nos ecossistemas. Atualmente, no Uruguai estão sendo analisadas estratégias de controle para erradicar a mosca da bicheira (MB), Cochliomyia hominivorax (Diptera: Calliphoridae), um ectoparasita obrigatório que causa miíase em vertebrados de sangue quente, incluindo o homem. A perda de uma espécie implica um risco de extinções secundárias e efeitos em cascata que dependem da função ecológica da espécie que se perde e da capacidade do resto das espécies com as quais interage para compensar a sua perda. Para avaliar o impacto ecológico da erradicação da MB, analisamos sua redundância ecológica, seu efeito como agente regulador indireto para outras espécies e sua participação em funções críticas do ecossistema. Concluímos que a MB apresenta alta redundância funcional na maioria de suas interações ecológicas, não desempenha um papel importante como agente regulador de outras espécies e não desempenha um papel importante em funções críticas do ecossistema. Sem ignorar as lacunas de informação que certamente existem sobre a rede de interações ecológicas do NWS no Uruguai, estimamos que é improvável que sua erradicação cause extinções secundárias ou efeitos em cascata nas redes de interações ecológicas que integra. Para detectar oportunamente possíveis impactos durante o curso do programa, recomenda-se monitorar os ecossistemas usando indicadores relacionados a parceiros diretos e indiretos nas interações ecológicas da MB
Leaf proline content and its relation to fruit load and flowering in citrus under field conditions
Abstract Citrus species grown in temperate zones have sprouting inhibited in winter and this is retaken in spring when they also bloom. The main factor that defines the vegetative or reproductive destiny of the buds is the presence of fruits in development. Low winter temperatures slow plant metabolism, which has been reported as necessary for the expression of the reproductive program. During the winter period of the annual cycle, osmotically active compounds such as proline are increased as part of the cold tolerance response. We investigated whether the presence of developing fruit and the application of exogenous gibberellins affect the proline level in citrus leaves. In an orchard of adult ‘Montenegrina’ mandarin trees, leaf proline contents were measured over two rest periods for branches with or without fruits. Branches that bloomed, the ones that did not have developing fruits, had higher proline levels as well as higher proline: chlorophyll and proline: total amino acid ratios than did branches with fruits. However, the application of exogenous gibberellins, which reduced flowering, did not affect proline content during the same periods. We discuss the ways in which proline may be involved in floral induction in citrus
Intensificación agrícola : oportunidades y amenazas para un país productivo y natural
Prólogo -- La Universidad al servicio de la República -- Colección Artículo 2 – Introducción --
Capítulo 1 : La Agricultura en Uruguay y su Evolución -- Capítulo 2 : Biotecnología moderna, cultivares transgénicos y proceso de adopción en Uruguay -- Capítulo 3 : La erosión de suelos en sistemas agrícolas -- Capítulo 4 : Valorización y conservación de la biodiversidad en Uruguay --
Capítulo 5 : Impactos socio-económicos de la expansión agrícol
Review on ecological interactions of the Cochliomyia hominivorax fly and assessment of the possible impacts of its eradication in Uruguay
Controlling a pest species raises questions about the harmful effects its eradication could cause in ecosystems. Currently, in Uruguay are being analyzed strategies to eradicate the New World Screwworm (NWS), Cochliomyia hominivorax (Diptera: Calliphoridae), an obligatory ectoparasite that causes myiasis in warm-blooded vertebrates, including humans. The loss of a species implies a risk of secondary extinctions and cascading effects that depend on the ecological function of the species and the capacity of the rest of the species with which it interacts to compensate for its loss. To assess the ecological impact of the NWS eradication, we analyzed its ecological redundancy, its effect as an indirect regulatory agent for other species, and its participation in critical ecosystem functions. We conclude that the NWS presents high functional redundancy in most ecological interactions. It does not play an essential role as a regulatory agent of other species and does not play an important role in critical ecosystem functions. Without ignoring the information gaps that certainly exist about the ecological interactions network of the NWS in Uruguay, we estimate that its eradication is unlikely to cause secondary extinctions or cascading effects in the networks it integrates. In order to timely detect possible impacts during the course of the program, it is recommended to monitor the ecosystems using indicators related to direct and indirect partners in the ecological interactions of the NWS
The Coronavirus Anxiety Scale: Cross-National Measurement Invariance and Convergent Validity Evidence
Coronavirus Anxiety Scale (CAS) is a widely used measure that captures somatic symptoms of coronavirus-related anxiety. In a large-scale collaboration spanning 60 countries (Ntotal = 21,513), we examined the CAS’s measurement invariance and assessed the convergent validity of CAS scores in relation to the fear of COVID-19 (FCV-19S) and the satisfaction with life (SWLS-3) scales. We utilized both conventional exact invariance tests and alignment procedures, with results revealing that the single-factor model fit the data well in almost all countries. Partial scalar invariance was supported in a subset of 56 countries. To ensure the robustness of results, given the unbalanced samples, we employed resampling techniques both with and without replacement and found the results were more stable in larger samples. The alignment procedure demonstrated a high degree of measurement invariance with 9% of the parameters exhibiting noninvariance. We also conducted simulations of alignment using the parameters estimated in the current model. Findings demonstrated reliability of the means but indicated challenges in estimating the latent variances. Strong positive correlations between CAS and FCV-19S estimated with all three different approaches were found in most countries. Correlations of CAS and SWLS-3 were weak and negative, but significantly differed from zero in several countries. Overall, the study provided support for the measurement invariance of the CAS and offered evidence of its convergent validity while also highlighting issues with variance estimation
Trust in government moderates the association between fear of COVID-19 as well as empathic concern and preventive behaviour
With the COVID-19 pandemic, behavioural scientists aimed to illuminate reasons why people comply with (or not) large-scale cooperative activities. Here we investigated the motives that underlie support for COVID-19 preventive behaviours in a sample of 12,758 individuals from 34 countries. We hypothesized that the associations of empathic prosocial concern and fear of disease with support towards preventive COVID-19 behaviours would be moderated by trust in the government. Results suggest that the association between fear of disease and support for COVID-19 preventive behaviours was strongest when trust in the government was weak (both at individual- and country-level). Conversely, the association with empathic prosocial concern was strongest when trust in the government was high, but this moderation was only found at individual-level scores of governmental trust. We discuss how motivations may be shaped by socio-cultural context, and outline how findings may contribute to a better understanding of collective action during global crises
The Coronavirus Anxiety Scale: Cross-National Measurement Invariance and Convergent Validity Evidence
Coronavirus Anxiety Scale (CAS) is a widely used measure that captures somatic symptoms of coronavirus-related anxiety. In a large-scale collaboration spanning 60 countries (Ntotal = 21,513), we examined the CAS’s measurement invariance and assessed the convergent validity of CAS scores in relation to the fear of COVID-19 (FCV-19S) and the satisfaction with life (SWLS-3) scales. We utilized both conventional exact invariance tests and alignment procedures, with results revealing that the single-factor model fit the data well in almost all countries. Partial scalar invariance was supported in a subset of 56 countries. To ensure the robustness of results, given the unbalanced samples, we employed resampling techniques both with and without replacement and found the results were more stable in larger samples. The alignment procedure demonstrated a high degree of measurement invariance with 9% of the parameters exhibiting noninvariance. We also conducted simulations of alignment using the parameters estimated in the current model. Findings demonstrated reliability of the means but indicated challenges in estimating the latent variances. Strong positive correlations between CAS and FCV-19S estimated with all three different approaches were found in most countries. Correlations of CAS and SWLS-3 were weak and negative, but significantly differed from zero in several countries. Overall, the study provided support for the measurement invariance of the CAS and offered evidence of its convergent validity while also highlighting issues with variance estimation