Models and applications for risk assessment and prediction of Asian soybean rust epidemics

Asian rust of soybean [Glycine max (L.) Merril] is one of the most important fungal diseases of this crop worldwide. The recent introduction of Phakopsora pachyrhiziSyd. & P. Syd in the Americas represents a major threat to soybean production in the main growing regions, and significant losses have already been reported. P. pachyrhizi is extremely aggressive under favorable weather conditions, causing rapid plant defoliation. Epidemiological studies, under both controlled and natural environmental conditions, have been done for several decades with the aim of elucidating factors that affect the disease cycle as a basis for disease modeling. The recent spread of Asian soybean rust to major production regions in the world has promoted new development, testing and application of mathematical models to assess the risk and predict the disease. These efforts have included the integration of new data, epidemiological knowledge, statistical methods, and advances in computer simulation to develop models and systems with different spatial and temporal scales, objectives and audience. In this review, we present a comprehensive discussion on the models and systems that have been tested to predict and assess the risk of Asian soybean rust. Limitations, uncertainties and challenges for modelers are also discussed

Influence of culture media and growth periods on the sporulation Septoria glycines

Com o objetivo de obter um meio de cultura que proporcione produção rápida e abundante de esporos de Septoria glycines (Hemmi), agente causal da mancha-parda-da-folha-da-soja, foi efetuado o presente trabalho. Inicialmente compararam-se fontes de carbono e de nitrogênio e substâncias reguladoras de crescimento. Posteriormente com base nos primeiros resultados alcançados, foram comparados os meios de cultura usados como testemunhas (Czapek ágar e BDA) agregados de fatores de crescimento nas doses que propiciaram a maior produção de esporos. Estes foram avaliados em cinco épocas de crescimento. Nos primeiros ensaios, os fatores de crescimento extrato de malte, extrato de levedura e tiamina foram superiores aos meios básicos. No ensaio final, mantiveram-se com a máxima produção de esporos, nas cinco diferentes épocas de leitura efetuadas ao longo de 25 dias, os tratamentos contendo o fator de crescimento extrato de levedura. A maior produção de esporos foi obtida, quando a cultura alcançou 25 dias de desenvolvimento, com o tratamento Czapec ágar + 4 g/l de extrato de levedura. The object of the present study was to find a new culture medium to provide rapid and abundant Septoria glycines (Hemmi) sporulation, the causal agent of brown spot disease on soybean leaves. First, carbon and nitrogen sources and growth regulators were compared. Later, based on the first results obtained, the culture media used as checks, associated with growth factors in doses which resulted in the greatest spore production, were compared (Czapek agar and PDA). These were evaluated in five growth periods. In the first trials, the malt extract, yeast extract and thiamine growth factors were greater than the basic media. In the final trial, the treatments containing the yeast extract growth factor continued with the greatest spore production in the five different periods observed during 25 days. The greatest spore production was obtained when the culture reached 25 days of development, with the Czapek agar medium + 4 g/l of yeast extract.

Cue-Elicited Craving in Heroin Addicts at Different Abstinent Time: An fMRI Pilot Study

Objective: We evaluated the effect of short-term and long-term heroin abstinence on brain responses to heroin-related cues using functional magnetic resonance imaging (fMRI). Methods: Eighteen male heroin addicts following short-term abstinence and 19 male heroin addicts following long-term abstinence underwent fMRI scanning while viewing heroin-related and neutral images. Cue-elicited craving and withdrawal symptoms in the subjects were measured. Results: Following short-term abstinence, greater activation was found in response to heroin cues compared to neutral cues in bilateral temporal, occipital, posterior cingulate, anterior cingulate, thalamus, cerebellum, and left hippocampus. In contrast, activations in bilateral temporal and occipital and deactivations in bilateral frontal, bilateral parietal, left posterior cingulate, insula, thalamus, dorsal striatum, and bilateral cerebellum were observed following long-term abstinence. Direct comparisons between conditions showed greater brain reactivity in response to smoking cues following short-term abstinence. In addition, short-term abstinence had more serious withdrawal symptoms than the long-term. Conclusion: The present findings indicate that compared to short-term, long-term abstinence manifests less serious withdrawal symptoms and significantly decreases neural responses to heroin-related cues in brain regions subserving visual sensory processing, attention, memory, and action planning. These findings suggest that long-term abstinence can decrease the salience of conditioned cues, thereby reducing the risk of relapses. The study's limitations are noted