Chuva de sementes: dinâmica de dispersão na presença de uma espécie exótica invasora, Artocarpus heterophyllus Lam. (jaqueira), no Parque Estadual da Ilha Grande, Angra dos Reis, RJ

A chuva de sementes é a dinâmica de dispersão de uma floresta, representando o que chega ao solo por meio dos agentes dispersores. Na comunidade de plantas, as síndromes de dispersão predominantes permitem entender os estádios sucessionais, estrutura e o nível de conservação da vegetação. No Brasil, a jaqueira, Artocarpus heterophyllus, é considerada uma espécie exótica invasora, que foi introduzida no período colonial. Essa invasão biológica pode comprometer a dispersão dos diásporos de espécies nativas pela chuva de sementes, já que a dispersão é influenciada pela distribuição espacial das plantas e pelas barreiras presentes no ambiente. O trabalho teve por objetivo verificar se a jaqueira, por ser uma espécie exótica invasora, influência na composição e abundância da chuva de sementes. O estudo foi realizado em floresta Atlântica, localizada no Parque Estadual da Ilha Grande, RJ. Foram utilizados para a coleta da chuva de semente 16 coletores de 1m de diâmetro, em áreas com (C) e sem (S) jaqueira, totalizando 32 coletores verificados mensalmente durante um ano de coleta. As análises estatísticas realizadas foram ANOVA, Regressão e NMDS, com o objetivo de verificar se a presença da jaqueira estaria influenciando na chuva de sementes quanto a riqueza, composição e abundância. Foram coletadas 320 amostras e contabilizadas 166.376 sementes, sendo encontrados 84 morfoespécies, 29 espécies em 25 famílias e 55 morfoespécies não identificadas. As áreas sem (S) jaqueira apresentaram maior riqueza, menor abundância e maior diversidade. Nas áreas com jaqueira (C) a abundância de sementes nativas apresentou uma relação negativa com a abundância dessa exótica nas parcelas. A composição e a abundância dos diásporos não tiveram uma separação nítida entre as áreas com e sem jaqueiras, como mostrado no NMDS. Porém, quando analisado o primeiro eixo do NMDS com a abundância de jaqueiras, a ordenação das grades mostrou ter uma relação com a abundância de jaqueiras. As principais síndromes de dispersão observadas no trabalho, referente às espécies que foram identificadas, foram à anemocoria e a zoocoria, sendo esta ultima síndrome a mais abundante entre as áreas. Os resultados mostraram que a presença das jaqueiras afeta, negativamente a chuva de sementes no Parque Estadual da Ilha Grande. Uma menor riqueza e abundância de sementes nativas alcançaram o solo nas áreas com jaqueira (C) podendo afetar a sucessão e a dinâmica da floresta.

Levantamento florístico de Floresta Atlântica no sul do Estado de São Paulo, Parque Estadual Intervales, Base Saibadela

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Composição florística de comunidades epifíticas vasculares em unidades de conservação no Estado de São Paulo

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Caracterización morfofisiológica de semillas de especies leñosas distribuidas en dos zonas secas presentes en el Sur del Ecuador

Sudamérica es una de las zonas con mayor cantidad de bosque seco tropical a nivel mundial. No obstante, estos bosques han sido poco conocidos y la mayoría de estudios han estado orientados hacia los bosques húmedos tropicales. Los bosques secos se han reducido drásticamente y siguen muy amenazados, corriendo el riesgo de desaparecer en los próximos años. Por ello, es fundamental, generar investigación aplicada para la conservación inmediata de los ecosistemas secos tropicales. En Ecuador, la situación no es diferente y las zonas secas catalogadas como biodiversas están en constante amenaza. Los pocos estudios realizados en Ecuador sobre zonas secas, han permitido mejorar nuestro conocimiento referente a la diversidad y abundancia de las especies, relaciones planta-planta y síndromes de dispersión. No existen estudios sobre caracteres morfológicos en frutos y semillas de las especies leñosas de bosque seco. Sin embargo, nuestra comprensión de la dinámica y estructura de las comunidades ecológicas de zonas secas poco estudiadas, puede mejorar rápidamente mediante el estudio y enfoque de rasgos morfofisiológicos funcionales. El objetivo general del presente estudio fue aportar al conocimiento de la ecología y biología de semillas de zonas secas tropicales mediante el análisis y evaluación de rasgos morfofisiológicos de frutos y semillas de una comunidad de especies leñosas. El estudio se realizó en una zona de bosque y matorral seco, ubicados al sur occidente del Ecuador, a una altitud comprendida entre los 250 a 1 200 m s.n.m. caracterizada por una marcada estacionalidad ambiental, con lluvias desde diciembre a abril y una estación seca de mayo a noviembre. Precipitación media anual de 500 mm con una temperatura media anual de 20° a 26 °C. La zona de estudio forma parte de la región Tumbesina compartida entre el sur del Ecuador y el norte del Perú con gran diversidad de especies vegetales endémicas. Para el estudio se colectaron frutos con semillas maduras previamente a su dispersión de entre ocho y diez individuos de 80 especies entre árboles y arbustos más representativos de los bosques secos ecuatorianos. De los frutos colectados se utilizó una muestra al azar de 50 frutos y semillas por especie para los diferentes análisis. Se midió y evaluó 18 rasgos morfológicos y fisiológicos cuantitativos y cualitativos de frutos, semillas y de la especie. Se realizaron diferentes análisis de asociación y correlación entre los rasgos evaluados, con cinco variables ambientales registradas de las 109 parcelas establecidas en el área de estudio, además analizamos el tipo de dormición y comparamos la respuesta germinativa a la deshidratación relacionada con dos comunidades secas, matorral y bosque seco. Los resultados mostraron que las especies presentan gran heterogeneidad en rasgos continuos de las semillas. La variabilidad fue más evidente en rasgos como tamaño, volumen, masa y número de semillas por fruto. Sin embargo, una alta proporción de las especies tiende a producir una semilla por fruto. Además, la mayoría de las especies de bosque seco se caracterizan por no poseer algún tipo de apéndices o areola en sus semillas, forma ovalada y sin endospermo. La reserva nutritiva de las semillas se encuentra especialmente en los cotiledones de los embriones. Se encontraron seis tipos diferentes de embriones y la mayoría de las especies presentó embriones gruesos e invertidos. La dispersión de semillas está dominada por zoocoria en un 38 %, con relación a anemocoria (22 %) y autocoria (19 %). Sin embargo, encontramos que el 70 % de las especies posee frutos secos. Los análisis de dormición en las semillas de bosque seco, mostraron que el 60 % de las especies de bosque seco presentaron semillas con algún tipo de latencia, menor a la encontrada en especies de bosque deciduo tropical y sabanas, sin embargo, la dormición de las especies de bosque seco fue mayor al porcentaje de especies con dormición de bosque semiperenne y selva lluviosa tropical. La dormición física constituyó el 35 % de las especies de bosque seco, seguido del 12 % con dormición fisiológica, mientras que solamente una especie tuvo dormición morfológica. Encontramos que la dormición de las semillas de las especies en estudio se relaciona significativamente con el tipo y función del embrión y con el endospermo. Existieron relaciones significativas entre los rasgos morfológicos de los frutos, semillas, embriones y atributos de los individuos de 46 especies, aunque en algunos casos con coeficientes de correlación bajos. Hubo pocas relaciones entre los rasgo morfológicos de las semillas con las variables ambientales registradas. Solamente el tipo de testa y la presencia de apéndices en las semillas mostraron relación con el pH y la temperatura media del suelo. No obstante usando el modelo fouth corner-RLQ, no se encontraron asociaciones claras ni significativas entre rasgos morfológicos de semillas y frutos con variables ambientales. Al medir el efecto de la deshidratación en las semillas de los dos hábitats secos tropicales: bosque y matorral seco, los resultados determinaron que tanto las semillas de las especies leñosas de ambientes más áridos (matorral seco) están en gran medida pre-adaptadas a la desecación que las especies de ambientes menos áridos (bosque seco). Los tratamientos de deshidratación ejercieron un efecto negativo en los porcentajes de germinación en todas las especies, excepto para C. platanifolia. Los resultados más sorprendentes se registraron para Senna alata que mostró germinación extremadamente baja o incluso sin germinación a contenidos de humedad de la semillas de 0,10 g H2O g de peso seco. Las curvas de germinación difirieron significativamente entre los tratamientos de deshidratación en cada especie. Aportar al conocimiento la fisiología de la deshidratación y los límites de tolerancia de las semillas de bosque y matorral seco ayudará a entender mejor el papel de este rasgo en la ecología de las semillas y dinámica de las comunidades áridas tropicales. El estudio demostró, que la adaptación ecológica de las semillas de las especies leñosas de bosque seco a factores ambientales extremos, puede verse reflejada en una red de interacciones y correlaciones complejas entre los propios rasgos morfológicos y fisiológicos continuos y cuantitativos, sobre todo en rasgos internos de las semillas, quienes ejercerían una mayor influencia en toda la red de interacciones. Si bien, los rasgos de las semillas no mostraron fuertes relaciones con las variables ambientales, posiblemente las asociaciones presentes entre rasgos morfológicos pudiesen predecir en cambio interacciones entre especies y comportamientos y procesos relacionados con la tolerancia a la deshidratación y dormición de las semillas. ABSTRACT South America is one of the areas with the largest number of tropical dry forest in the world. However, these forests have been poorly understood and most studies have been directed to tropical rainforests. Dry forests have been drastically reduced and are very threatened, risking desaparecerer in the next years. It is therefore essential, generate applied research for conservation of tropical dry ecosystems. In Ecuador the situation is no different and dry areas classified as biodiverse are under constant threat. The few studies made in Ecuador on drylands have improved our knowledge concerning the diversity and abundance of species, plant-plant relationships and dispersion syndromes. Morphological studies on fruits and seeds of woody dry forest species do not exist. However, our understanding of the dynamics and structure of ecological communities dryland little studied, may improve quickly through the study and functional approach morphophysiological traits. The overall objective of this study was to contribute to the knowledge of the ecology and biology of tropical dry seeds through analysis and evaluation of morphophysiological traits of fruits and seeds of a community of woody species. The study was conducted in an area of dry scrub forest, located at the southwest of Ecuador, at an altitude between 250 to 1200 m asl. Environmental characterized by a marked seasonality, with rainfall from December to April and a dry season from May to November. Annual rainfall of 500 mm with an average annual temperature of 20° to 26 °C. The study area is part of the shared Tumbesina region between southern Ecuador and northern Peru with a great diversity of endemic plant species. For the study, we collected fruit and seed madure of eight and ten individuos of 80 species of trees and shrub most representated of the Ecuador dry forest. We selected a sample of 50 fruits and seeds for different analysis. We measure and evaluate 18 morphological and physiological traits of fruits, seeds and species. We perform analysis and correlation between traits associated with five environmental variables taken from the 109 plots established in the study area also analyze and compare the germination response to dehydration related to two dry communities, scrub and dry forest. The results showed that the species have great heterogeneity in continuous seed traits. Variability was more evident in features such as size, volume, mass, and number of seeds per fruit. However, a high proportion of species tends to produce a seed per fruit. In addition, most of the species of dry forest is characterized by not having some sort of ppendices or areola in its seeds, oval form and without endosperm. The nutrient reserves of seeds are especially in the cotyledons of the embryos. Six different embryos were found and most of the species presented thick and inverted embryos. Seed dispersal zoochory is dominated by 38 %, relative to anemochory (22 %) and autochory (19 %). However, we found that 70 % of the species has dried fruits. The analysis of dormancy from tropical dry forest, showed that 60 % of species showed seed dormancy, down from species found in tropical deciduous forest and savanna, however dormancy dry forest species was higher than the percentage of forest species dormancy semi-evergreen and tropical rain forest. Physical dormancy corresponds to 35 % of species, followed by 12 % with physiological dormancy, while only one species had morphological dormancy. We found that dormancy of the seeds was significantly related to the type and function of the embryo and the endospemo. There were significant relationships between morphological traits of fruits, seeds, embryos and attributes of individuals of 46 species, although in some cases with low correlation coefficients. There was little relationship between the morphologic traits of the seeds with the registered environmental variables. Only the type of tesla and the presence of appendages on the seeds showed relation to pH and the mean soil temperature. However, using the fourth corner-RLQ model, neither clear nor significant between morphological traits of seeds and fruits associations with environmental variables were found. The effect of dehydration on seeds of two tropical dry forest habitats was evident in dry scrub. The results determined that both the seeds of woody species forest and dry scrub are pre-adapted to drier conditions. Dehydration treatments exerted a negative effect on germination percentage in all species, except for C. platanifolia. However, all species germinated in treatments of extreme dryness, but in low percentages. The most striking results were recorded for Senna alata showed no germination when its moisture content was 0.10 g H2O g dry weight. Germination curves differ significantly between the treatments of dehydration in each species. Contribute to the knowledge of physiology and dehydration tolerance limits seeds dry scrub forest and help you better understand the role of this trait in seed ecology and dynamics of tropical arid communities. The study showed that the ecological adaptation of seeds of woody species of dry forest to extreme environmental factors may be reflected in a complex web of interactions and correlations between morphological and physiological traits continuous and quantitative themselves, especially in internal seed traits, who exerted a major influence on the entire network of interactions. While the seed traits showed strong relationships with environmental variables possibly present associations between morphological traits could predict interactions between species and change behaviors related to desiccation tolerance and seed dormancy processes.

Simulations of pollutant dispersion at toll plazas using three-dimensional CFD models

Toll plazas are particularly susceptible to build-ups of vehicle-emitted pollutants because vehicles pass through in low gear. To look at this, three-dimensional computational fluid dynamics simulations of pollutant dispersion are used on the standard k e turbulence model. The effects of wind speed, wind direction and topography on pollutant dispersion were discussed. The Wuzhuang toll plaza on the Hefei-Nanjing expressway is considered, and the effects of the retaining walls along both sides of the plaza on pollutant dispersion is analysed. There are greater pollutant concentrations near the tollbooths as the angle between the direction of the wind and traffic increases implying that retaining walls impede dispersion. The slope of the walls has little influence on the variations in pollutant concentration.

Ticagrelor, a platelet aggregation inhibitor for the potential prevention and treatment of arterial thrombosis and acute coronary syndromes

Ticagrelor is an orally active ADP P2Y12 receptor antagonist in development by AstraZeneca plc for the reduction of recurrent ischemic events in patients with acute coronary syndromes (ACS). Prior to the development of ticagrelor, thienopyridine compounds, such as clopidogrel, were the focus of research into therapies for ACS. Although the thienopyridines are effective platelet aggregation inhibitors, they are prodrugs and, consequently, exert a slow onset of action. In addition, the variability in inter-individual metabolism of thienopyridine prodrugs has been associated with reduced efficacy in some patients. Ticagrelor is not a prodrug and exhibits a more rapid onset of action than the thienopyridine prodrugs. In clinical trials conducted to date, ticagrelor was a potent inhibitor of ADP-induced platelet aggregation and demonstrated effects that were comparable to clopidogrel. In a phase II, short-term trial, the bleeding profile of participants treated with ticagrelor was similar to that obtained with clopidogrel; however, an increased incidence of dyspnea was observed - an effect that has not been reported with the thienopyridines. Considering the occurrence of dyspnea, and the apparent non-superiority of ticagrelor to clopidogrel, it is difficult to justify a clear benefit to the continued development of ticagrelor. Outcomes from an ongoing phase III trial comparing ticagrelor with clopidogrel in 18,000 patients with ACS are likely to impact on the future development of ticagrelor.

Difference and dispersion : educational research in a postmodern context

Difference and Dispersion is the fourth in a series of annual research papers produced by doctoral students from The Graduate School of Education, The University of Queensland, following their presentation at the School’s annual Postgraduate Research Conference in Education. The work featured herein celebrates the diversity of cultural and disciplinary backgrounds of education researchers who come from as far afield as Germany, Hong Kong, China, Nigeria, Russia, Singapore, Thailand and of course different parts of Australia. In keeping with a postmodern epistemology, ‘difference’ and ‘dispersion’ are key themes in apprehending the multiplicity of their research topics, methodologies, methods and speaking/writing positions. From widely differing contexts and situations, these writers address the consequences, implications and possibilities for education at the beginning of the third millennium. Their interest ranges from location-specific issues in schools and classrooms, change in learning contexts and processes, educational discourses and relations of power in diverse geographical settings, and the differing articulations of the local and the global in situated policy contexts. Conceived and developed in a spirit of ongoing dialogue with and insight to alternative views and visions of education and society, this edited collection exemplifies the quality in diversity and the high levels of scholarship and supervision at one of Australia’s finest Graduate Schools of Education.

Psychosocial outcomes of Hong Kong Chinese diagnosed with acute coronary syndromes: a prospective repeated measures study.

BACKGROUND: Western studies have suggested that emotional stress and distress impacted on the morbidity and mortality in people following acute coronary events. Symptoms of anxiety and depression have been associated with re-infarction and death, prolonged recovery and disability and depression may precipitate the client's low self-esteem. This study examined perceived anxiety, depression and self-esteem of Hong Kong Chinese clients diagnosed with acute coronary syndrome (ACS) over a 6-month period following hospital admission. OBJECTIVES: To examine: DESIGN: A prospective, repeated measures design with measures taken on two occasions over a 6-month period; (1) within the 1st week of hospital admission following the onset of ACS and (2) at 6 months follow up. SETTING AND PARTICIPANTS: Convenient sample of 182 voluntary consented clients admitted with ACS to a major public hospital in Hong Kong who could communicate in Chinese, complete questionnaires, cognitive intact, and were haemodynamically stable and free from acute chest pain at the time of interview. METHODS: Baseline data were obtained within 1 week after hospital admission. The follow-up data was collected 6 months after hospital discharge. The Chinese version of the Hospital Anxiety and Depression Scale (HADS), State Self-esteem Scale (SSES), and Rosenberg's Self-Esteem Scale (RSES) were used to assess anxiety and depression, state self-esteem, and trait self-esteem, respectively. RESULTS: Findings suggested gender differences in clients' perception in anxiety, depression and self-esteem. Improvements in clients' perception of these variables were evident over the 6-month period following their acute coronary events. CONCLUSION: The study confirmed the western notion that psychosocial problems are common among coronary clients and this also applies to Hong Kong Chinese diagnosed with ACS. Further studies to explore effective interventions to address these psychosocial issues are recommended.