Efeito da radiação UV-B sobre a capacidade antagônica de Clonostachys rosea a Botrytis cinerea em discos de folha de morango.

Resumo:: As atividades antrópicas estão alterando a concentração de gases na atmosfera, o ozônio da troposfera é um dos afetados e consequentemente a incidência de raios ultravioleta B (UV-B) na superfície da Terra tem sido alterada. A sensibilidade à radiação UV-B é uma das limitações do uso de agentes de biocontrole a campo. O objetivo deste trabalho foi avaliar o efeito da radiação UV-B em um isolado de Clonostachys rosea e quantificar a capacidade antagônica a Botrytis cinerea em discos de folhas de morango. Foram utilizadas quatro concentrações de conídios de C. rosea e quatro diferentes doses de radiação UV-B, sendo metade dos discos irradiados desafiados com conídios de B. cinerea. As concentrações de conídios de C. rosea acima de 105 conídios mL-1 apresentaram maior tolerância a radiação UV-B e apresentou nível de controle do patógeno superior a 75%, mesmo com a exposição à radiação. De acordo com os resultados, além de mostrar menor crescimento sob radiação UV-B, conídios de C. rosea apresentaram menor capacidade antagônica ao patógeno. Estudos adicionais são necessários para observar a tolerância de isolados de B. cinerea à radiação UV-B e assim, sugerir que um ambiente com radiação UV-B aumentada possa favorecer o patógeno

Research approaches, adaptation strategies, and knowledge gaps concerning the impacts of climate change on plant diseases.

This review discusses the present trends in studies on the impacts of climate change on plant diseases. Firstly, the approaches used for studying the potential effects of altered temperature, water availability, CO2 and O3 air concentrations, and UV-B radiation on components of the disease cycle are explained and discussed. Next, the impact of changes in climate patterns on the geographic and temporal distribution of diseases by integrating biological and epidemiological models into geographic and climate databases are assessed. Finally, adaptation strategies are discussed and areas where there is a recognized lack of knowledge are highlighted. The literature shows that different pathosystems respond in different ways to climate change. Thus, case-by-case studies on the responses of crop species or varieties and their diseases to climate change are necessary. In addition to that, wide-scale projections of disease risk are necessary in order to identify research priorities, whereas industry must be strategically directed and public policies developed to establish adaptation measures and to prevent potential food security crisis. Only by conducting long-term and multidisciplinary studies can we reduce the uncertainty regarding the effects of climate change on plant diseases

Voluntary Risk Taking By Young Bicyclists:A Case Study of University Students at Montreal

Young bicyclists in Montreal are taking voluntary risks such as bicycling without wearing helmet and braking system of bicycle although they are aware of the presence of danger. This article analyses the behaviour of young bicyclists taking voluntary risks. The university students in Montreal are considered as the case study since they are more risk takers and the bicycle is a favorite mode of transport among them. This study reveals that half of the respondents did not use helmets. They were also spontaneously taking a risk by high speeding, violating signals, bicycling in mixed traffic, ignoring protective equipment after dark, and avoiding the bicycle designated roads. They were taking voluntary risks based on their attitude, subjective norm and perceived behavioural control. They did not perceive the severity of risks since they experienced relevant and unremarkable minor injuries. The attractiveness of risk and accomplishing the risk activities encouraged the young bicyclists to take voluntary risks repeatedly. Increasing feelings of vulnerability among young bicyclists reduce voluntary risks taking attitude and physical and psychological sufferings of the victims of bicycle-related accidents. Findings of this study suggest that the City of Montreal as well as other cities consider the behaviour of bicyclists particularly the young people to avoid bicycle-related accidents along with other physical measures

Avaliação do desempenho de um pivo central da baixa pressão equipado com tubos de descida.

At the Corn and Sorghum National Research Center in Sete Lagoas, Minas Gerais State, an evaluation was made of the performance of a low pressure central pivot equipped with drop sparay, operating at 100% of its displacement capacity. The tests carried out were the following: without drop spray; drop spray of 1.2m; 2.0m and 2.6m lenght. For each test, the uniformity coefficients of Christiansen (CUC) and distribution (CUD), the application efficiency, in potential (EPa), and the highest precipitation intensity were determined. It was concluded that: The lenght of drop spray did not affect distribution uniformity; The collected water plate at the end of the pivot line showed a large variation; Topographic characteristics influenced distribution uniformity; Drop spray increased application efficiency, in potential, reducing pressure at the diffusor exit. Proximity of the diffusor to the ground decreased the covering diameter and increase precipitation density

Suite of simple metrics reveals common movement syndromes across vertebrate taxa

ecause empirical studies of animal movement are most-often site- and species-specific, we lack understanding of the level of consistency in movement patterns across diverse taxa, as well as a framework for quantitatively classifying movement patterns. We aim to address this gap by determining the extent to which statistical signatures of animal movement patterns recur across ecological systems. We assessed a suite of movement metrics derived from GPS trajectories of thirteen marine and terrestrial vertebrate species spanning three taxonomic classes, orders of magnitude in body size, and modes of movement (swimming, flying, walking). Using these metrics, we performed a principal components analysis and cluster analysis to determine if individuals organized into statistically distinct clusters. Finally, to identify and interpret commonalities within clusters, we compared them to computer-simulated idealized movement syndromes representing suites of correlated movement traits observed across taxa (migration, nomadism, territoriality, and central place foraging)