Alterações morfométricas em dois híbridos de palma de óleo submetidos ao déficit hídrico.

O déficit hídrico causa significativos prejuízos ao crescimento vegetativo das plantas. A magnitude desses danos pode variar dentre cultivares, variedades e híbridos de uma mesma espécie. Nesta pesquisa, objetivou-se quantificar as variações no crescimento de dois híbridos de palma de óleo (BRS C 2501 e BRS Manicoré) a fim de comparar suas respostas ao déficit hídrico e inferir acerca de suas tolerâncias ao estresse. Os híbridos foram avaliados sob plena irrigação e sob déficit hídrico induzido pela suspensão completa da irrigação. As avaliações foram realizadas no momento da diferenciação dos tratamentos (Dia 0) e após 57 dias da suspensão da irrigação (Dia 57), quando as plantas estressadas de ambos os híbridos apresentaram médias de potencial hídrico foliar na antemanhã de -4,0 MPa. O estresse causou reduções significativas na altura das plantas e no número de folíolos, com efeito na área foliar total e massa seca de folhas. Foi observado ainda menor massa seca de caule e raízes nas plantas estressadas de ambos os híbridos. Conclui-se que ambos os híbridos apresentaram similares padrões de resposta ao estresse aplicad

Trocas gasosas em dois híbridos de palma de óleo submetidos ao déficit hídrico progressivo.

No estado do Pará, áreas que apresentam período seco definido ao longo do ano são consideradas inapropriadas ao cultivo do dendezeiro. Portanto, a busca por genótipos mais tolerantes à seca é uma estratégia interessante. Assim, esta pesquisa objetivou avaliar a magnitude das alterações nas trocas gasosas e na eficiência instantânea do uso da água em dois híbridos de palma de óleo (BRS Manicoré e BRS C2501) submetidos a um déficit hídrico progressivo do solo a fim de avaliar suas capacidades de tolerância à seca. O experimento foi conduzido em delineamento inteiramente casualizado comparando-se plantas irrigadas e não irrigadas de ambos os híbridos por um período de 57 dias. Foi observado que o déficit hídrico promoveu reduções significativas no potencial hídrico foliar, cujo valor mínimo foi de -4,40 MPa para o BRS C2501 e de -4,03MPa para o BRS Manicoré. Ambos os híbridos apresentaram reduções significativas em todas as variáveis de trocas gasosas avaliadas, porém, essas reduções foram mais expressivas para o BRS C 2501, principalmente a partir do 28o dia de experimento. Os resultados indicam que o BRS C 2501 apresenta uma maior sensibilidade ao déficit hídrico que o BRS Manicoré

7th Drug hypersensitivity meeting: part two

No abstract availabl

Vegetation chlorophyll estimates in the Amazon from multi-angle MODIS observations and canopy reflectance model

As a preparatory study for future hyperspectral missions that can measure canopy chemistry, we introduce a novel approach to investigate whether multi-angle Moderate Resolution Imaging Spectroradiometer (MODIS) data can be used to generate a preliminary database with long-term estimates of chlorophyll. MODIS monthly chlorophyll estimates between 2000 and 2015, derived from a fully coupled canopy reflectance model (ProSAIL), were inspected for consistency with eddy covariance fluxes, tower-based hyperspectral images and chlorophyll measurements. MODIS chlorophyll estimates from the inverse model showed strong seasonal variations across two flux-tower sites in central and eastern Amazon. Marked increases in chlorophyll concentrations were observed during the early dry season. Remotely sensed chlorophyll concentrations were correlated to field measurements (r2 = 0.73 and r2 = 0.98) but the data deviated from the 1:1 line with root mean square errors (RMSE) ranging from 0.355 μg cm−2 (Tapajós tower) to 0.470 μg cm−2 (Manaus tower). The chlorophyll estimates were consistent with flux tower measurements of photosynthetically active radiation (PAR) and net ecosystem productivity (NEP). We also applied ProSAIL to mono-angle hyperspectral observations from a camera installed on a tower to scale modeled chlorophyll pigments to MODIS observations (r2 = 0.73). Chlorophyll pigment concentrations (ChlA+B) were correlated to changes in the amount of young and mature leaf area per month (0.59 ≤ r2 ≤ 0.64). Increases in MODIS observed ChlA+B were preceded by increased PAR during the dry season (0.61 ≤ r2 ≤ 0.62) and followed by changes in net carbon uptake. We conclude that, at these two sites, changes in LAI, coupled with changes in leaf chlorophyll, are comparable with seasonality of plant productivity. Our results allowed the preliminary development of a 15-year time series of chlorophyll estimates over the Amazon to support canopy chemistry studies using future hyperspectral sensors. © 2017 Elsevier B.V

Comparison of Interferon-γ Release Assay to Two Cut-Off Points of Tuberculin Skin Test to Detect Latent Mycobacterium tuberculosis Infection in Primary Health Care Workers

BackgroundAn interferon-γ release assay, QuantiFERON-TB (QFT) test, has been introduced an alternative test for the diagnosis of latent Mycobacterium tuberculosis infection (LTBI). Here, we compared the performance of QFT with tuberculin skin test (TST) measured at two different cut-off points among primary health care work (HCW) in Brazil.MethodsA cross-sectional study was carried out among HCWs in four Brazilian cities with a known history of high incidence of TB. Results of the QFT were compared to TST results based on both ≥5 mm and ≥10 mm as cut-off points.ResultsWe enrolled 632 HCWs. When the cut-off value of ≥10 mm was used, agreement between QFT and TST was 69% (k = 0.31), and when the cut-off of ≥5 mm was chosen, the agreement was 57% (k = 0.22). We investigated possible factors of discordance of TST vs QFT. Compared to the TST-/QFT- group, risk factors for discordance in the TST+/QFT- group with TST cut-off of ≥5 mm included age between 41-45 years [OR = 2.70; CI 95%: 1.32-5.51] and 46-64 years [OR = 2.04; CI 95%: 1.05-3.93], BCG scar [OR = 2.72; CI 95%: 1.40-5.25], and having worked only in primary health care [OR = 2.30; CI 95%: 1.09-4.86]. On the other hand, for the cut-off of ≥10 mm, BCG scar [OR = 2.26; CI 95%: 1.03-4.91], being a household contact of a TB patient [OR = 1.72; CI 95%: 1.01-2.92] and having had a previous TST [OR = 1.66; CI 95%: 1.05-2.62], were significantly associated with the TST+/QFT- group. No statistically significant associations were found among the TST-/QFT+ discordant group with either TST cut-off value.ConclusionsAlthough we identified BCG vaccination to contribute to the discordance at both TST cut-off measures, the current Brazilian recommendation for the initiation of LTBI treatment, based on information gathered from medical history, TST, chest radiograph and physical examination, should not be changed