179 research outputs found

    Sturm-Liouville boundary conditions for a second order ODE

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    We study the semilinear second order ODE u00 + g(t, u) = 0 under the following Sturm- Liouville boundary condition au(0) + bu0(0) = u0 and cu(T) + du0(T) = uT . We obtain solutions by topological methods. Moreover, we show that a solution may be constructed recursively, under appropriate conditions

    Preliminary Results from the 1997 Bottom Trawl Survey in the NAFO Regulatory Area for Divisions 3NO

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    As the previous years, a stratified-random bottom trawl survey was performed in NAFO Regulatory area (Division 3NO) during 26th April to 17th May. The survey, which covered offshore areas on the Grand Bank, was conducted following the same procedures and the same vessel and gear of the 1995 and 1996 surveys (Paz et al. 1995; 1996). The area and the strata to be covered by the survey were based on the stratification charts and tables in Bishop (1994)

    Preliminary Results from the 96 Spanish Bottom Trawl Survey in the NAFO Regulatory Area for Divisions 3NO

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    As the last year a stratified-random bottom trawl survey was performed in NAFO Regulatory Area (Divisions 3NO) during May: 7th to 24th. The survey, wich covered offshore areas of the Grand Bank, was conducted following the sames procedures and the same vessel and gear of the 1995 survey (Paz, et al, 1995). The area and strata to be covered by the survey were based on the stratification charts and tables in Bishop (1994)

    GAME9 regulates the biosynthesis of steroidal alkaloids and upstream isoprenoids in the plant mevalonate pathway

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    Steroidal glycoalkaloids (SGAs) are cholesterol-derived molecules produced by solanaceous species. They contribute to pathogen defence but are toxic to humans and considered as anti-nutritional compounds. Here we show that GLYCOALKALOID METABOLISM 9 (GAME9), an APETALA2/Ethylene Response Factor, related to regulators of alkaloid production in tobacco and Catharanthus roseus, controls SGA biosynthesis. GAME9 knockdown and overexpression in tomato and potato alters expression of SGAs and upstream mevalonate pathway genes including the cholesterol biosynthesis gene STEROL SIDE CHAIN REDUCTASE 2 (SSR2). Levels of SGAs, C24-alkylsterols and the upstream mevalonate and cholesterol pathways intermediates are modified in these plants. Delta(7)-STEROL-C5(6)-DESATURASE (C5-SD) in the hitherto unresolved cholesterol pathway is a direct target of GAME9. Transactivation and promoter-binding assays show that GAME9 exerts its activity either directly or cooperatively with the SlMYC2 transcription factor as in the case of the C5-SD gene promoter. Our findings provide insight into the regulation of SGA biosynthesis and means for manipulating these metabolites in crops

    Decadal variability 2010-2021 of zooplankton community at the Guadalquivir estuary (southern Spain)

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    A Long Term Ecological Research Program has been monitoring the Guadalquivir estuary meso- and macro- zooplankton community monthly since January 2010. As an important nursery area for many marine species (fish and crustacean) from the Gulf of Cadiz, whose juveniles and recruits depend on zooplankton as main prey, understanding how abiotic and biotic factors determine zooplankton community structure it´s necessary to unreveal recruitment variability. We sampled throughout the whole salinity gradient, 2 locations, the two diurnal ebb and flood tides during the new moon days using a 100 μm zooplankton net. Zooplankton community is mainly composed by copepods and mysids. While the exotic Acartia tonsa calanoid copepod is the most abundant specie by abundance, mysid Mesopodopsis slabberi contribute the most to total biomass, followed by mysids Rhopalophthalmus tartessicus and Neomysis integer. Other abundant groups were copepods Acartia bifilosa and Acartia clausii, Calanipeda aquaedulcis, Paracalanus parvus and Acanthocyclops robustus, cladocera Pleopis polyphaemoides, together with veliger larvae, Cirripeda and Ostracoda, and Decapoda larvae. About total biodiversity, we found up to 183 species, estimating a total mean Species Richness of 9.7 (minimum 2- maximum 33) per sample, mean Shannon Diversity Index 3.27, Pielou Evenness 0.50 and mean betadiversity 0.630. While copepods area abundant form fall to early spring and summer, mysid density peaks form spring to fall. Community is structured by Salinity, but Temperature, Turbidity, Nitrate, Nitrite and Dissolved Oxygen were also important variables leading spatio-temporal variability, mainly when estuary recives high freshwater discharges from Alcala del Río dam

    The half-time talk: A mixed-method examination of youth-elite football coaches’ behaviours and team-management strategies

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    Football, unlike some other team sports, includes limited game interruptions for coaches to easily communicate with players and affect their performance. However, a reduced number of studies have explored how coaches attempt to influence players during half-time. This study examined football coaches’ behaviours during half-time and their perceptions underpinning their talks’ delivery. Five Spanish coaches (Mage = 32.2, SD = 8.8) working for a La Liga academy were systematically observed during half-time talks (n = 20) and participated in a semi-structured interview each. Half-time talks were coded using a modified version of the Coach Analysis and Intervention System, and semi-structured interviews were analysed following thematic analysis procedures. Instruction and feedback were the most employed behaviours for four coaches, with younger age-group coaches employing greater divergent questioning and in-talk player participation. Furthermore, data suggested that coaches conferred with their staff, before entering the changing room and rapidly progressed from divergent to convergent questions and feedback and instruction. The team's ‘level of play’ was the most perceived relevant factor affecting the verbal and vocal strategies of coaches’ messages, albeit the score gained importance for coaches of older age-groups. This study is pioneering, examining how coaches attempt to influence their players during half-time talks of competitive youth football

    TweetLID : a benchmark for tweet language identification

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    Language identification, as the task of determining the language a given text is written in, has progressed substantially in recent decades. However, three main issues remain still unresolved: (1) distinction of similar languages, (2) detection of multilingualism in a single document, and (3) identifying the language of short texts. In this paper, we describe our work on the development of a benchmark to encourage further research in these three directions, set forth an evaluation framework suitable for the task, and make a dataset of annotated tweets publicly available for research purposes. We also describe the shared task we organized to validate and assess the evaluation framework and dataset with systems submitted by seven different participants, and analyze the performance of these systems. The evaluation of the results submitted by the participants of the shared task helped us shed some light on the shortcomings of state-of-the-art language identification systems, and gives insight into the extent to which the brevity, multilingualism, and language similarity found in texts exacerbate the performance of language identifiers. Our dataset with nearly 35,000 tweets and the evaluation framework provide researchers and practitioners with suitable resources to further study the aforementioned issues on language identification within a common setting that enables to compare results with one another

    Group-level selection increases cooperation in the public goods game

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    When groups compete for resources, some groups will be more successful than others, forcing out less successful groups. Group-level selection is the most extreme form of group competition, where the weaker group ceases to exist, becoming extinct. We implement group-level selection in a controlled laboratory experiment in order to study its impact on human cooperation. The experiment uses variations on the standard linear public goods game. Group-level selection operates through competition for survival: the least successful, lowest-earning groups become extinct, in the sense that they no longer are able to play the game. Additional control treatments include group comparison without extinction, and extinction of the least successful individuals across groups. We find that group-level extinction produces very high contributions to the provision of the public good, while group comparison alone or individual extinction fail to cause higher contributions. Our results provide stark evidence that group-level selection enhances within-group cooperation
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