2,852 research outputs found

    Evolução da Sustentabilidade nas Regiões Vitícolas do Norte eAlentejo

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    The wine sector currently lacks nuclear fea-tures, which makes Portugal’s producing per-formance drift away from the frontline world-wide wine producers. The aim of this paper is to evaluate the evolution of the Portuguese wine industry’s performance through the world and national available statistical data. Also, this work tries to evaluate the sustainability dyna-mic regarding theNorth and Alentejo, using the Portuguese Farm Accountancy Data Network from 2001 to 2012. From the sustain-nability indicators, the results show that Alente-jo presents the best performance in terms of environmental sustainability. The North has an increasing economic dimension of sustainabil-ity and good social performance. The conclu-sions suggest that academic research can im-prove the wine industry’s overall orientation to sustainability.O setor vitivinícola carece atualmente de ca-racterísticas nucleares que fazem o desempenho produtivo do país afastar-se dos líderes da pro-dução mundial de vinho. O objetivo deste traba-lho consiste em avaliar a evolução do desempe-nho do setor vitivinícola português através dos dados estatísticos disponíveis, a nível mundial e nacional. Pretende-se ainda avaliar a dinâmica da sua sustentabilidade, no Norte e Alentejo, através dos dados da Rede de Informação de Contabilidade Agrícola de 2001 a 2012. Dos indicadores de sustentabilidade obtidos verifi-ca-se que o Alentejo obtém o melhor desempe-nho em termos de sustentabilidade ambiental. O Norte tem uma tendência para melhorar a di-mensão económica da sustentabilidade e revela bom desempenho social. As conclusões suge-rem que a investigação académica pode melho-rar a orientação geral desta indústria para a sua sustentabilidade.info:eu-repo/semantics/publishedVersio

    Slow and population specific evolutionary response to a warming environment

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    Adaptation to increasingly warmer environments may be critical to avoid extinction. Whether and how these adaptive responses can arise is under debate. Though several studies have tackled evolutionary responses under different thermal selective regimes, very few have specifically addressed the underlying patterns of thermal adaptation under scenarios of progressive warming conditions. Also, considering how much past history affects such evolutionary response is critical. Here, we report a long-term experimental evolution study addressing the adaptive response of Drosophila subobscura populations with distinct biogeographical history to two thermal regimes. Our results showed clear differences between the historically differentiated populations, with adaptation to the warming conditions only evident in the low latitude populations. Furthermore, this adaptation was only detected after more than 30 generations of thermal evolution. Our findings show some evolutionary potential of Drosophila populations to respond to a warming environment, but the response was slow and population specific, emphasizing limitations to the ability of ectotherms to adapt to rapid thermal shifts.info:eu-repo/semantics/publishedVersio

    Translocating the blood-brain barrier using electrostatics

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    Copyright © 2012 Ribeiro,Domingues, Freire,Santos and Castanho. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.Mammalian cell membranes regulate homeostasis, protein activity, and cell signaling. The charge at the membrane surface has been correlated with these key events. Although mammalian cells are known to be slightly anionic, quantitative information on the membrane charge and the importance of electrostatic interactions in pharmacokinetics and pharmacodynamics remain elusive. Recently, we reported for the first time that brain endothelial cells (EC) are more negatively charged than human umbilical cord cells, using zeta-potential measurements by dynamic light scattering. Here, we hypothesize that anionicity is a key feature of the blood-brain barrier (BBB) and contributes to select which compounds cross into the brain. For the sake of comparison, we also studied the membrane surface charge of blood components—red blood cells (RBC), platelets, and peripheral blood mononuclear cells (PBMC).To further quantitatively correlate the negative zeta-potential values with membrane charge density, model membranes with different percentages of anionic lipids were also evaluated. From all the cells tested, brain cell membranes are the most anionic and those having their lipids mostly exposed, which explains why lipophilic cationic compounds are more prone to cross the blood-brain barrier.Fundação para a Ciência e Tecnologia — Ministério da Educação e Ciência (FCT-MEC, Portugal) is acknowledged for funding (including fellowships SFRH/BD/42158/2007 to Marta M.B. Ribeiro, SFRH/BD/41750/2007 to Marco M. Domingues and SFRH/BD/70423/2010 to João M. Freire) and project PTDC/QUI-BIQ/119509/2010. Marie Curie Industry-Academia Partnerships and Pathways (European Commission) is also acknowledged for funding (FP7-PEOPLE-2007-3-1-IAPP, Project 230654)

    No evidence for short‐term evolutionary response to a warming environment in Drosophila

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    Adaptive evolution is key in mediating responses to global warming and may sometimes be the only solution for species to survive.Such evolution will expectedly lead to changes in the populations’ thermal reaction norm and improve their ability to cope with stressful conditions. Conversely, evolutionary constraints might limit the adaptive response. Here, we test these expectations by performing a real-time evolution experiment in historically differentiated Drosophila subobscura populations. We address the phenotypic change after nine generations of evolution in a daily fluctuating environment with average constant temperature, or in a warming environment with increasing average and amplitude temperature across generations. Our results showed that (1) evolution under a global warming scenario does not lead to a noticeable change in the thermal response; (2) historical background appears to be affecting responses under the warming environment, particularly at higher temperatures; and (3) thermal reaction norms are trait dependent: although lifelong exposure to low temperature decreases fecundity and productivity but not viability,high temperature causes negative transgenerational effects on productivity and viability, even with high fecundity. These findings in such an emblematic organism for thermal adaptation studies raise concerns about the short-term effciency of adaptive responses to the current rising temperatures.info:eu-repo/semantics/acceptedVersio

    High developmental temperature leads to low reproduction despite adult temperature

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    Phenotypic plasticity can help organisms cope with changing thermal conditions and it may depend on which life-stage the thermal stress is imposed: for instance, exposure to stressful temperatures during development can trigger a positive plastic response in adults. Here, we analyze the thermal plastic response of laboratory populations of Drosophila subobscura, derived from two contrasting latitudes of the European cline. We measured reproductive performance through fecundity characters, after the experimental populations were exposed to five thermal treatments, with different combinations of developmental and adult temperatures (14°C, 18°C, or 26°C). Our questions were whether (1) adult performance is changed with exposure to higher (or lower) temperatures during development; (2) flies raised at lower temperatures outperform those developed at higher ones, supporting the “colder is better” hypothesis; (3) there is a cumulative effect on adult performance of exposing both juveniles and adults to higher (or lower) temperatures; (4) there is evidence for biogeographical effects on adult performance. Our main findings were that (1) higher developmental temperatures led to low reproductive performance regardless of adult temperature, while at lower temperatures reduced performance only occurred when colder conditions were persistent across juvenile and adult stages; (2) flies raised at lower temperatures did not always outperform those developed at other temperatures; (3) there were no harmful cumulative effects after exposing both juveniles and adults to higher temperatures; (4) both latitudinal populations showed similar thermal plasticity patterns. The negative effect of high developmental temperature on reproductive performance, regardless of adult temperature, highlights the developmental stage as very critical and most vulnerable to climate change and associated heat waves.info:eu-repo/semantics/publishedVersio

    Beneficial developmental acclimation in reproductive performance under cold but not heat stress

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    Thermal plasticity can help organisms coping with climate change. In this study, we analyse how laboratory populations of the ectotherm species Drosophila subobscura, originally from two distinct latitudes and evolving for several generations in a stable thermal environment (18 °C), respond plastically to new thermal challenges. We measured adult performance (fecundity traits as a fitness proxy) of the experimental populations when exposed to five thermal regimes, three with the same temperature during development and adulthood (15-15 °C, 18-18 °C, 25-25 °C), and two where flies developed at 18 °C and were exposed, during adulthood, to either 15 °C or 25 °C. Here, we test whether (1) flies undergo stress at the two more extreme temperatures; (2) development at a given temperature enhances adult performance at such temperature (i.e. acclimation), and (3) populations with different biogeographical history show plasticity differences. Our findings show (1) an optimal performance at 18 °C only if flies were subjected to the same temperature as juveniles and adults; (2) the occurrence of developmental acclimation at lower temperatures; (3) detrimental effects of higher developmental temperature on adult performance; and (4) a minor impact of historical background on thermal response. Our study indicates that thermal plasticity during development may have a limited role in helping adults cope with warmer - though not colder - temperatures, with a potential negative impact on population persistence under climate change. It also emphasizes the importance of analysing the impact of temperature on all stages of the life cycle to better characterize the thermal limits.info:eu-repo/semantics/publishedVersio

    The effect of instruction to synchronize over step frequency while walking with auditory cues on a treadmill

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    "Available online 16 January 2014"Walking to a pacing stimulus has proven useful in motor rehabilitation, and it has been suggested that spontaneous synchronization could be preferable to intentional synchronization. But it is still unclear if the paced walking effect can occur spontaneously, or if intentionality plays a role. The aim of this work is to analyze the effect of sound pacing on gait with and without instruction to synchronize, and with different rhythmic auditory cues, while walking on a treadmill. Firstly, the baseline step frequency while walking on a treadmill was determined for all participants, followed by experimental sessions with both music and footstep sound cues. Participants were split into two groups, with one being instructed to synchronize their gait to the auditory stimuli, and the other being simply told to walk. Individual auditory cues were generated for each participant: for each trial, cues were provided at the participant’s baseline walking frequency, at 5% and 10% above baseline, and at 5% and 10% below baseline. This study’s major finding was the role of intention on synchronization, given that only the instructed group synchronized their gait with the auditory cues. No differences were found between the effects of step or music stimuli on step frequency. In conclusion, without intention or cues that direct the individual’s attention, spontaneous gait synchronization does not occur during treadmill walking.This study was financed by the Portuguese Foundation for Science and Technology and FEDER (projects FCOMP-01-0124-FEDER-007560, FCOMP-01-0124-FEDER-022674, PEst-OE/ECI/UI4047/2011, PTDC/TRA/67859/2006 and PTDC/EEA-ELC/112137/2009), by the German Cluster of Excellence Hearing4all, and by the Academy of Finland project 13266239-Audiovisual Space

    Detrimental impact of a heatwave on male reproductive behaviour and fertility

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    Understanding how heatwaves impact on different aspects of mating behaviour and fertility is getting increasingly important. In this context, laboratory fertility and mating experiments involving manipulation and exposure of insects to different thermal conditions are common procedures. To conduct such experiments practical methods such as dyes are needed for an easy, non-invasive discrimination of individuals. We report here a study measuring the effect of an extended heat stress applied to males on several parameters of mating behaviour and fertility of laboratory populations of Drosophila subobscura derived from two distinct European locations. We found highly detrimental effects of heatwave on mating behaviour—with longer (courtship and copulation) latencies and lower mating occurrence but no changes in mating duration—and fertility, with reduced fecundity and reproductive success. Furthermore, we also tested the efficacy of food dye as a marker for individual discrimination and mating occurrence. While food dye did not allow to infer the occurrence of a mating based on a transfer of coloration from male to female, it did not affect mating and fertility, attesting its utility has a method for discriminating individuals within mating experiments in the context of thermal studies. Importantly, despite the fact that the heatwave was only applied in males, we observed an impact on behaviour of females that mated with stressed males, by often refusing their nuptial feeding. This opens possibilities for further integrated research on the changes of female and male mating behaviour and fertility under different thermal scenarios.info:eu-repo/semantics/publishedVersio

    Phage amplification coupled with loop-mediated isothermal amplification (PA-LAMP) for same-day detection of viable Salmonella Enteritidis in raw poultry meat

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    Salmonella Enteritidis is the main serotype responsible for human salmonellosis in the European Union. One of the main sources of Salmonella spp. in the food chain are poultry products, such as eggs or chicken meat. In recent years, molecular methods have become an alternative to culture dependent methods for the rapid screening of Salmonella spp. In this work, the strain S. Enteritidis S1400, and previously isolated and characterized bacteriophage PVP-SE2, were used to develop and evaluate a same-day detection method combining Phage Amplification and Loop-mediated isothermal amplification (PA-LAMP) to specifically detect viable S. Enteritidis in chicken breast. This method is based on the detection of the phage DNA rather than bacterial DNA. The virus is added to the sample during pre-enrichment in buffered peptone water, where it replicates in the presence of viable S. Enteritidis. The detection of phage DNA allows, on the one hand to detect viable bacteria, since viruses only replicate in them, and on the other hand to increase the sensitivity of the method since for each infected S. Enteritidis cell, hundreds of new viruses are produced. Two different PA-LAMP detection strategies were evaluated, a real time fluorescence and a naked-eye detection. The present method could down to 0.2 fg/L of pure phage DNA and a concentration of viral particles of 2.2 log PFU/mL. After a short Salmonella recovery step of 3 h and a co-culture of 4 h of the samples with phage particles, both real-time fluorescence and naked-eye method showed a LoD95 of 6.6 CFU/25 g and a LoD50 of 1.5/25 g in spiked chicken breast samples. The entire detection process, including DNA extraction and LAMP analysis, can be completed in around 8 h. In the current proof-of-concept, the novel PA-LAMP obtained comparable results to those of the reference method ISO 6579, to detect Salmonella Enteritidis in poultry meat.Dr. Alexandre Lamas was funded by a postdoctoral fellowship from Xunta de Galicia (Axudas de apoio a étapa de formación posdoutoral IN606B (Modalidade A)). Dr. Alejandro Garrido-Maestu acknowledges funding from the Fundação para a Ciência e Tecnologia through the Scientific Employment Stimulus Program (2021.02810.CEECIND).info:eu-repo/semantics/publishedVersio
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