1,714 research outputs found

    Local conditions influence thermal sensitivity of pencil urchin populations (Eucidaris galapagensis) in the Galápagos Archipelago

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    The responses of ectothermic organisms to changes in temperature can be modified by acclimatization or adaptation to local thermal conditions. Thus, the effect of global warming and the deleterious effects of extreme heating events (e.g., heatwaves) on the metabolism and fitness of ectotherms can be population specific and reduced at warmer sites. We tested the hypothesis that when environmental temperature is greater, grazer populations in the Galápagos are less thermally sensitive (potentially due to acclimatization or adaptation). We quantified the acute thermal sensitivity of four populations of the pencil sea urchin, Eucidaris galapagensis, by measuring individual oxygen consumption across a range of temperatures. Thermal performance curves were estimated for each population and compared to local thermal conditions 2 months prior to collection. Results indicate that E. galapagensis populations were adapted and/or acclimatized to short-term local temperature as populations at warmer sites had substantially higher thermal tolerances. The acute thermal optimum (Topt) for the warmest and coolest site populations differed by 3 °C and the Topt was positively correlated with maximum temperature recorded at each site. Additionally, temperature-normalized respiration rate and activation energy (E) were negatively related to the maximum temperature. Understanding the temperature-dependent performance of the pencil urchin (the most significant mesograzer in this system), including its population specificity, provides insight into how herbivores and the functions they perform might be affected by further ocean heating

    Developmental Regulation of Transcription in Touriga Nacional Berries under Deficit Irrigation

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    Grapevine (Vitis vinifera L.) is one of the most economically important crops worldwide, especially due to the economic relevance of wine production. Abiotic stress, such as drought, may contribute to low yield, shifts in quality, and important economic loss. The predicted climate change phenomena point to warmer and dryer Mediterranean environmental conditions; as such, it is paramount to study the effects of abiotic stress on grapevine performance. Deficit irrigation systems are applied to optimize water use efficiency without compromising berry quality. In this research, the effect of two deficit irrigation strategies, sustained deficit irrigation (SDI) and regulated deficit irrigation (RDI), in the grape berry were assessed. The effects of different levels of drought were monitored in Touriga Nacional at key stages of berry development (pea size, véraison, and full maturation) through RNA-Seq transcriptome analysis and by specific differentially expressed genes (DEGs) monitoring through RT-qPCR. Handy datasets were obtained by bioinformatics analysis of raw RNA-Seq results. The dominant proportion of transcripts was mostly regulated by development, with véraison showing more upregulated transcripts. Results showed that primary metabolism is the functional category more severely affected under water stress. Almost all DEGs selected for RT-qPCR were significantly upregulated in full maturation and showed the highest variability at véraison and the lowest gene expression values in the pea size stageinfo:eu-repo/semantics/publishedVersio

    Effectiveness of brief intervention and contact for suicide attempters: A randomized controlled trial in five countries

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    Objective: To determine whether brief intervention and contact is effective in reducing subsequent suicide mortality among suicide attempters in low and middle-income countries. Methods: Suicide attempters (n = 1867) identified by medical staff in the emergency units of eight collaborating hospitals in five culturally different sites (Campinas, Brazil; Chennai, India; Colombo, Sri Lanka; Karaj, Islamic Republic of Iran; and Yuncheng, China) participated, from January 2002 to October 2005, in a randomized controlled trial to receive either treatment as usual, or treatment as usual plus brief intervention and contact (BIC), which included patient education and follow-up. Overall, 91 completed the study. The primary study outcome measurement was death from suicide at 18-month follow-up. Findings: Significantly fewer deaths from suicide occurred in the BIC than in the treatment-as-usual group (0.2 versus 2.2, respectively; �2 = 13.83, P < 0.001). Conclusion: This low-cost brief intervention may be an important part of suicide prevention programmes for underresourced low-and middle-income countries

    Cations extraction of sandy-clay soils from Cavado valley, Portugal, using sodium salts solutions

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    Cases of contamination by metals in the water wells of the Cavado Valley in north-west Portugal can be attributed to the heavy leaching of clay soils due to an excess of nitrogen resulting from the intensive use of fertilisers in agricultural areas. This work focuses on the natural weathering characteristics of soils, particularly the clay material, through the study of samples collected near the River Cavado. Samples taken from various sites, after physico-chemical characterisation, were subjected to clay dissolution tests, using sodium salts of different ionic forces, to detect the relationship between certain physico-chemical parameters of water, such as pH, nitrate, chloride and sulphate content, in the dissolution of clay and the subsequent extraction of such cations as Al, Fe and K. In acidic sandy clay soils, the mineralogical composition of which was characterised by a predominance of quartz, micas, kaolinite and K-feldspars, decreases of the clay material/water pH ratio increases dissolution of the micaceous and K-feldspars phases. The presence of nitrates in the aqueous solution apparently advanced the extraction of all three cations Al, Fe and K. The specific surface area of the clay material showed a significant correlation with the main kinetic parameters of cation extraction.Têm ocorrido casos de contaminações de águas de poços, por metais, no vale do Rio Cávado, região noroeste de Portugal. A princípio, poderiam ser explicáveis pela elevada lixiviação dos solos arenoargilosos da região, quando da prática de adubações intensivas de nitrogênio em áreas agrícolas. Assim, estudaram-se as características do intemperismo natural dos solos, particularmente da fração argila, característica da margem norte do rio Cávado. Coletaram-se amostras de vários locais, que foram submetidas, após caracterização físico-química, a ensaios de dissolução a partir de soluções de sais de sódio com diferentes forças iônicas. O objetivo foi observar as relações de determinados parâmetros físico-químicos da água, tais como: pH, nitratos, cloretos e sulfatos na dissolução das argilas e a conseqüente extração de espécies químicas tais como Al, K e Fe. Para solos areno-argilosos, ácidos, cuja composição mineralógica se caracteriza por um predomínio de quartzo, micas, caulinita e feldspato-K, o abaixamento do pH da suspensão solo/água promove a solubilização das fases micáceas e feldspáticas. A presença do nitrato nas soluções aquosas promoveu aparentemente a extração de todos os três cátions: Al, K e Fe. O efeito da área superfícial específica das partículas dos solos condicionou fortemente vários dos parâmetros cinéticos estudados relativos à extração dos cátions.(undefined
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