Infecção natural por tripanosomatídeos (Kinetoplastida: Trypanosomatidae) em Lutzomyia umbratilis (Diptera: Psychodidae) em áreas de leishmaniose tegumentar americana no Amazonas, Brasil

Durante o período de 2002 a 2003 foram realizadas coletas de flebotomíneos em duas áreas do estado do Amazonas (Base de treinamento militar - BI1 e Tarumã Mirim). Nessas coletas foram capturadas um total de 1.440 fêmeas de Lutzomyia (Nyssomyia) umbratilis. Lu.umbratilis é a principal responsável pela transmissão da Leishmaniose Tegumentar Americana (LTA) ao norte do Rio Amazonas. Do total coletado apenas 15 espécimens (ou 1,04%) apresentaram infecção natural por tripanosomatídeos, sendo 12 na BI1 e 3 em Tarumã-Mirim. Isso representou uma taxa de infecção de 1,66% (12 dos 720 capturados em BI1) e 0,42% (3 dos 720 em Tarumã-Mirim). Estes resultados confirmam as informações prévias por outros autores de reduzidos valores de infecção natural por tripanosomatídeos em flebotomíneos, mesmo em áreas altamente endêmicas para leishmaniose.During the period of 2002 to 2003, there were collected sand flies in two areas of Amazon State (Forest Combat Training Base - BI1 and Tarumã-Mirim). Were collected the 1440 L. (Nyssomyia) umbratilis female. Lu. umbratilis is the main responsible for the transmission of American Tegumentary Leishmaniasis (ATL) in the northern of Amazon River. Only 15 specimens (or 1,04%) presented natural infection with trypanosomatids, being 12 at Bl1 and 3 at Tarumã-Mirim. The infection rate was 1,66% (12 of the 720 collected at BI1) and 0,42% (3 of the 720 at Tarumã-Mirim). These results confirm the previous informations described by other authors that insects have low rates of natural infection by trypanosomatids even in high endemic areas for Leishmaniasis

Qualidade fisiológica de sementes de alface submetidas a diferentes temperaturas na presença e ausência de luz Physiological quality of lettuce seeds under different temperatures, in presence and ausence of light

O trabalho foi conduzido no Laboratório Didático e de Pesquisas em Sementes da Universidade Federal de Santa Maria, com o objetivo de avaliar o efeito da temperatura e da luz sobre a germinação e vigor das plântulas de alface. Foram utilizados os cultivares Elisa, Regina e Rainha de Maio e submetidos aos tratamentos de temperatura a 20; 25; 30; 35°C e 20-30°C, estabelecendo um experimento bifatorial (3x5), conduzido na presença e ausência de luz. Utilizou-se o substrato sobre papel em caixas plásticas de germinação, sob o delineamento inteiramente casualizado, com quatro repetições de 100 sementes por tratamento. Na presença de luz as sementes foram colocadas em germinador no qual se efetuou o controle fotoperiódico de 8 horas de luz e 16 horas de escuro, para cada dia. Na ausência de luz as sementes foram semeadas e mantidas no escuro, durante todo o teste, cobrindo-se as caixas plásticas de germinação com papel alumínio. As avaliações de tamanho de plântula e primeira contagem de germinação foram efetuadas no quarto dia, e a percentagem final de germinação no sétimo dia. Observou-se que, na ausência de luz, quanto menor a temperatura utilizada maiores foram a germinação e o vigor (determinado pela primeira contagem de germinação). Quando testados com luz, verificou-se, para os cultivares Elisa e Regina, que a germinação e os maiores tamanhos de plântulas não variam com as diferentes temperaturas, exceto para 35ºC, que se mostrou desaconselhável para as sementes de alface, por impedir a germinaç ão. Conclui-se que existe influência do genótipo sobre a qualidade fisioló gica das sementes. A luz é um fator limitante na germinação. Para os cultivares Elisa, Regina e Rainha de Maio, a melhor temperatura, dentre as estudadas, é de 20°C. Na presença de luz, a germinação e o desenvolvimento inicial ocorrem numa faixa ampla de temperatura (20°C a 30°C). A temperatura de 35°C induz à dormência secundária das sementes de alface.<br>The experiment on the different types of lettuce seeds, and the effects of light and temperature occured in the Didactic Laboratory of Researches in Seeds, of Santa Maria Federal University, Brazil. Elisa, Regina and Rainha de Maio, were selected and tested under the tempreatures of 20°C; 25°C; 30°C; 35°C; 20-30°C, for establish a bifactorial experiment separately conducted, with and without light. The substratum was used on paper in gerbox, with four repetitions of 100 seeds for treatment. The selected light conditions were 8 hours of light and 16 hours of darkness, for every day. For the condition without light an aluminum paper was placed over the gerboxes. The evaluations of plant size and first germination were made in the fourth day and the final percentage of germination, in the seventh day. It was observed that without light, the lower the temperature the more plants germanated. When tested with light it was found that with Elisa and Regina, the tempurature had no effect except at 35º, in which germination was impeded. In conclusion, exist influence of lettuce genotypes in physiological quality seeds. The light is a limiter factor in germination. Within the tested temperatures, it was found that 20ºC was the best for the three cultivars. In presence of light, the plants initial development occured within a wide strip of temperature (20°C to 30°C). Temperature of 35°C cause secondary dormancy in lettuce seeds

Seasonal updraft speeds change cloud droplet number concentrations in low-level clouds over the western North Atlantic

To determine the impact of dynamic and aerosol processes on marine low clouds, we examine the seasonal impact of updraft speed w and cloud condensation nuclei concentration at 0.43 % supersaturation (NCCN0.43%) on the cloud droplet number concentration (NC) of low-level clouds over the western North Atlantic Ocean. Aerosol and cloud properties were measured with instruments on board the NASA LaRC Falcon HU-25 during the ACTIVATE (Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment) mission in summer (August) and winter (February-March) 2020. The data are grouped into different NCCN0.43% loadings, and the density functions of NC and w near the cloud bases are compared. For low updrafts (w 3 ms-1), NC is impacted by the aerosol population, while at clean marine conditions cloud nucleation is aerosol-limited, and for high NCCN0.43% it is influenced by aerosols and updraft. The aerosol size distribution in winter shows a bimodal distribution in clean marine environments, which transforms to a unimodal distribution in high NCCN0.43% due to chemical and physical aerosol processes, whereas unimodal distributions prevail in summer, with a significant difference in their aerosol concentration and composition. The increase of NCCN0.43% is accompanied with an increase of organic aerosol and sulfate compounds in both seasons. We demonstrate that NC can be explained by cloud condensation nuclei activation through upwards processed air masses with varying fractions of activated aerosols. The activation highly depends on w and thus supersaturation between the different seasons, while the aerosol size distribution additionally affects NC within a season. Our results quantify the seasonal influence of w and NCCN0.43% on NC and can be used to improve the representation of low marine clouds in models. © 2022 Simon Kirschler et al.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

An Empirical Test of Ecodevelopmental Theory in Predicting HIV Risk Behaviors Among Hispanic Youth

Ecodevelopmental theory is a theoretical framework used to explain the interplay among risk and protective processes associated with HIV risk behaviors among adolescents. Although ecodevelopmentally based interventions have been found to be efficacious in preventing HIV risk behaviors among Hispanic youth, this theory has not yet been directly empirically tested through a basic research study in this population. The purpose of this cross-sectional study was to empirically evaluate an ecodevelopmentally based model using structural equation modeling, with substance use and early sex initiation as the two outcomes of the ecodevelopmental chain of relationships. The sample consisted of 586 Hispanic youth (M age = 13.6; SD = 0.75) and their primary caregivers living in Miami, Florida. Adolescent, parent, and teacher reports were used. The results provided strong support for the theoretical model. More specifically, the parent–adolescent acculturation gap is indirectly related both to early sex initiation and to adolescent substance use through family functioning, academic functioning, perceived peer sexual behavior, and perceived peer substance use. Additionally, parent’s U.S. orientation is associated with adolescent substance use and adolescent sex initiation through social support for parents, parental stressors, family functioning, academic functioning, and perceived peer sexual behavior and substance use. These findings suggest that HIV risk behaviors may best be understood as associated with multiple and interrelated ecological determinants