1,017 research outputs found

    Midday measurements of leaf water potential and stomatal conductance are highly correlated with daily water use of Thompson Seedless grapevines

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    A study was conducted to determine the relationship between midday measurements of vine water status and daily water use of grapevines measured with a weighing lysimeter. Water applications to the vines were terminated on August 24th for 9 days and again on September 14th for 22 days. Daily water use of the vines in the lysimeter (ETLYS) was approximately 40 L vine−1 (5.3 mm) prior to turning the pump off, and it decreased to 22.3 L vine−1 by September 2nd. Pre-dawn leaf water potential (ΨPD) and midday Ψl on August 24th were −0.075 and −0.76 MPa, respectively, with midday Ψl decreasing to −1.28 MPa on September 2nd. Leaf g s decreased from ~500 to ~200 mmol m−2 s−1 during the two dry-down periods. Midday measurements of g s and Ψl were significantly correlated with one another (r = 0.96) and both with ETLYS/ETo (r = ~0.9). The decreases in Ψl, g s, and ETLYS/ETo in this study were also a linear function of the decrease in volumetric soil water content. The results indicate that even modest water stress can greatly reduce grapevine water use and that short-term measures of vine water status taken at midday are a reflection of daily grapevine water us

    Conclusion : what's next ?

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    This book offered a broad overview of the different business models in the wine industry worldwide. It showed the diversity of this highly fragmented and extremely diverse sector. Above all, the different chapters showed that there is no dominant model and no guarantee of success at national scale in whatever we are talking about Old, New or New World wine countries. In particular, this book refutes the idea, however widespread in the Old World, that the model of the large, vertically integrated industries relying on one or more strong brands sold internationally would be the unique way for success in wine-producing countries. (...

    Reinforcement learning or active inference?

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    This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural policies that reproduce those optimised by reinforcement learning and dynamic programming. Critically, we do not need to invoke the notion of reward, value or utility. We illustrate these points by solving a benchmark problem in dynamic programming; namely the mountain-car problem, using active perception or inference under the free-energy principle. The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain

    Influence of soil water content and atmospheric conditions on leaf water potential in cv. "Touriga Nacional" deep-rooted vineyards

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    Abstract In this study, the influence of soil and atmosphere conditions on noon and basal leaf water potential of vines ‘‘Touriga Nacional’’ in the Da˜o region submitted to different irrigation treatments is analysed. Both indicators showed to be dependent on environmental conditions at the time of measurement. Leaf water potential at noon of fully watered plants was linearly related with atmospheric conditions, with values registered when vapour pressure deficit (VPD) was higher than approximately 3 kPa being no different from the values registered in stressed plants. Therefore, this indicator cannot be reliably used to distinguish different plant water stress levels when atmospheric conditions induce high evaporative demands. The basal leaf water potential (wb) was also influenced by VPD at the time of measurement for all soil water conditions. In well irrigated plants, it was even possible to establish a baseline that can therefore be used to identify nonwater stressed conditions (wb (MPa) = -0.062–0.0972 VPD (kPa), r2 = 0.78). A good correlation was found between soil humidity and wb. However, more than the average value of the whole thickness of soil monitored, the wb values were dependent on the distribution of soil humidity, with the plants responding to the presence of wet layers

    Photosynthetic Responses to Heat Treatments at Different Temperatures and following Recovery in Grapevine (Vitis amurensis L.) Leaves

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    BACKGROUND: The electron transport chain, Rubisco and stomatal conductance are important in photosynthesis. Little is known about their combined responses to heat treatment at different temperatures and following recovery in grapevines (Vitis spp.) which are often grown in climates with high temperatures. METHODOLOGY/FINDINGS: The electron transport function of photosystem II, the activation state of Rubisco and the influence of stomatal behavior were investigated in grapevine leaves during heat treatments and following recovery. High temperature treatments included 35, 40 and 45°C, with 25°C as the control and recovery temperature. Heat treatment at 35°C did not significantly (P>0.05) inhibit net photosynthetic rate (P(n)). However, with treatments at 40 and 45°C, P(n) was decreased, accompanied by an increase in substomatal CO(2) concentration (C(i)), decreases in stomatal conductance (g(s)) and the activation state of Rubisco, and inhibition of the donor side and the reaction center of PSII. The acceptor side of PSII was inhibited at 45°C but not at 40°C. When grape leaves recovered following heat treatment, P(n), g(s) and the activation state of Rubisco also increased, and the donor side and the reaction center of PSII recovered. The increase in P(n) during the recovery period following the second 45°C stress was slower than that following the 40°C stress, and these increases corresponded to the donor side of PSII and the activation state of Rubisco. CONCLUSIONS: Heat treatment at 35°C did not significantly (P>0.05) influence photosynthesis. The decrease of P(n) in grape leaves exposed to more severe heat stress (40 or 45°C) was mainly attributed to three factors: the activation state of Rubisco, the donor side and the reaction center of PSII. However, the increase of P(n) in grape leaves following heat stress was also associated with a stomatal response. The acceptor side of PSII in grape leaves was responsive but less sensitive to heat stress

    Sequential modulations of the Simon effect depend on episodic retrieval

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    Sequential modulations of conflict effects, like the reduction of the Simon effect after incompatible trials, have been taken to reflect the operation of a proactive control mechanism commonly called conflict monitoring. However, such modulations are often contaminated by episodic effects like priming and stimulus-response feature integration. It has previously been observed that if the episodic representation of a conflicting trial is altered by rotating the stimulus framing 180° around its axis, the subsequent “conflict adaptation” pattern is eliminated. In Experiment 1, we replicate the findings and provide the basic episodic interpretation. In Experiment 2, we extend the framework to include rotations of 90°, and verify that the episodic effects generalize to scenarios of neutral compatibility. Finally, in Experiment 3, we add complete, 360° rotations, and show that the episodic manipulation by itself does not eliminate the conflict adaptation patterns – as long as conditions favor episodic retrieval. The experiments are argued to demonstrate that an episodic account of the conflict adaptation effect can most parsimoniously account for the behavioral effects without relying on higher order cognition. Accordingly, we conclude that conflict adaptation can be understood either as critically depending on episodic retrieval, or alternatively reflecting only episodic retrieval itself

    The Current Crisis in Emergency Care and the Impact on Disaster Preparedness

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    <p>Abstract</p> <p>Background</p> <p>The Homeland Security Act (HSA) of 2002 provided for the designation of a critical infrastructure protection program. This ultimately led to the designation of emergency services as a targeted critical infrastructure. In the context of an evolving crisis in hospital-based emergency care, the extent to which federal funding has addressed disaster preparedness will be examined.</p> <p>Discussion</p> <p>After 9/11, federal plans, procedures and benchmarks were mandated to assure a unified, comprehensive disaster response, ranging from local to federal activation of resources. Nevertheless, insufficient federal funding has contributed to a long-standing counter-trend which has eroded emergency medical care. The causes are complex and multifactorial, but they have converged to present a severely overburdened system that regularly exceeds emergency capacity and capabilities. This constant acute overcrowding, felt in communities all across the country, indicates a nation at risk. Federal funding has not sufficiently prioritized the improvements necessary for an emergency care infrastructure that is critical for an all hazards response to disaster and terrorist emergencies.</p> <p>Summary</p> <p>Currently, the nation is unable to meet presidential preparedness mandates for emergency and disaster care. Federal funding strategies must therefore be re-prioritized and targeted in a way that reasonably and consistently follows need.</p

    Towards a national trauma registry for the United Arab Emirates

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    <p>Abstract</p> <p>Background</p> <p>Trauma is a major health problem in the United Arab Emirates (UAE) as well as worldwide. Trauma registries provide large longitudinal databases for analysis and policy improvement. We aim in this paper to report on the development and evolution of a national trauma registry using a staged approach by developing a single-center registry, a two-center registry, and then a multi-center registry. The three registries were established by developing suitable data collection forms, databases, and interfaces to these databases. The first two registries collected data for a finite period of time and the third is underway. The steps taken to establish these registries depend on whether the registry is intended as a single-center or multi-center registry.</p> <p>Findings</p> <p>Several issues arose and were resolved during the development of these registries such as the relational design of the database, whether to use a standalone database management system or a web-based system, and the usability and security of the system. The inclusion of preventive medicine data elements is important in a trauma registry and the focus on road traffic collision data elements is essential in a country such as the UAE. The first two registries provided valuable data which has been analyzed and published.</p> <p>Conclusions</p> <p>The main factors leading to the successful establishment of a multi-center trauma registry are the development of a concise data entry form, development of a user-friendly secure web-based database system, the availability of a computer and Internet connection in each data collection center, funded data entry personnel well trained in extracting medical data from the medical record and entering it into the computer, and experienced personnel in trauma injuries and data analysis to continuously maintain and analyze the registry.</p

    Context-dependent preferences in starlings: linking ecology, foraging and choice

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    Foraging animals typically encounter opportunities that they either pursue or skip, but occasionally meet several alternatives simultaneously. Behavioural ecologists predict preferences using absolute properties of each option, while decision theorists focus on relative evaluations at the time of choice. We use European starlings (Sturnus vulgaris) to integrate ecological reasoning with decision models, linking and testing hypotheses for value acquisition and choice mechanism. We hypothesise that options' values depend jointly on absolute attributes, learning context, and subject's state. In simultaneous choices, preference could result either from comparing subjective values using deliberation time, or from processing each alternative independently, without relative comparisons. The combination of the value acquisition hypothesis and independent processing at choice time has been called the Sequential Choice Model. We test this model with options equated in absolute properties to exclude the possibility of preference being built at the time of choice. Starlings learned to obtain food by responding to four stimuli in two contexts. In context [AB], they encountered options A5 or B10 in random alternation; in context [CD], they met C10 or D20. Delay to food is denoted, in seconds, by the suffixes. Observed latency to respond (Li) to each option alone (our measure of value) ranked thus: LA≈LC<LB<<LD, consistently with value being sensitive to both delay and learning context. We then introduced simultaneous presentations of A5 vs. C10 and B10 vs. C10, using latencies in no-choice tests to predict sign and strength of preference in pairings. Starlings preferred A5 over C10 and C10 over B10. There was no detectable evaluation time, and preference magnitude was predictable from latency differentials. This implies that value reflects learning rather than choice context, that preferences are not constructed by relative judgements at the time of choice, and that mechanisms adapted for sequential decisions are effective to predict choice behaviour.This work was supported by Biotechnology and Biological Sciences Research Council (BBSRC) Grant BB/G007144/1 to AK www.bbsrc.ac.uk; TM was supported by a Doctoral Grant from the Portuguese Foundation for Science and Technology (FCT) www.fct.pt/index.phtml.en. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Pharmacologically directed strategies in academic anticancer drug discovery based on the European NCI compounds initiative

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    Background: The European NCI compounds programme, a joint initiative of the EORTC Research Branch, Cancer Research Campaign and the US National Cancer Institute, was initiated in 1993. The objective was to help the NCI in reducing the backlog of in vivo testing of potential anticancer compounds, synthesised in Europe that emerged from the NCI in vitro 60-cell screen. Methods: Over a period of more than twenty years the EORTC—Cancer Research Campaign panel reviewed ~2000 compounds of which 95 were selected for further evaluation. Selected compounds were stepwise developed with clear go/no go decision points using a pharmacologically directed programme. Results: This approach eliminated quickly compounds with unsuitable pharmacological properties. A few compounds went into Phase I clinical evaluation. The lessons learned and many of the principles outlined in the paper can easily be applied to current and future drug discovery and development programmes. Conclusions: Changes in the review panel, restrictions regarding numbers and types of compounds tested in the NCI in vitro screen and the appearance of targeted agents led to the discontinuation of the European NCI programme in 2017 and its transformation into an academic platform of excellence for anticancer drug discovery and development within the EORTC-PAMM group. This group remains open for advice and collaboration with interested parties in the field of cancer pharmacology
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