4,568 research outputs found

    Acute exercise intensity and memory function: Evaluation of the transient hypofrontality hypothesis

    Get PDF
    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background and Objective: The transient hypofrontality hypothesis predicts that memory function will be impaired during high-intensity exercise, as a result of a need for metabolic and cognitive resources to be allocated toward sustaining movement, as opposed to performing a cognitive task. The purpose of these experiments was to evaluate this transient hypofrontality hypothesis. Materials and Methods: Experiment 1 involved participants (n = 24; Mage = 21.9 years) completing four counterbalanced visits. Two visits evaluated working memory function, either at rest or during a high-intensity bout of acute exercise. The other two visits evaluated episodic memory function, either at rest or during a high-intensity bout of acute exercise. Experiment 2 (n = 24; Mage = 20.9 years) extended Experiment 1 by evaluating memory function (working memory) across 4 counterbalanced conditions, including at rest and during light (30% of heart rate reserve; HRR), moderate (50% HRR) and high-intensity (80% HRR) acute exercise. Results: Experiment 1 demonstrated that, when compared to rest, both working memory and episodic memory were impaired during high-intensity acute exercise. Experiment 2 replicated this effect, but then also showed that, unlike high-intensity acute exercise, memory function was not impaired during low-and moderate-intensity acute exercise. Conclusions: Our experiments provide support for the transient hypofrontality hypothesis. Both working memory and episodic memory are impaired during high-intensity acute exercise. Working memory does not appear to be impaired during lower exercise intensities

    UNA PROPUESTA PARA LA ENSEÑANZA DEL FRANCÉS A TRAVÉS DE LA MARSELLESA

    Get PDF
    La investigación se desarrolló con los estudiantes de quinto año de la carrera de Licenciatura en Turismo de la Universidad de Ciego de Ávila Máximo Gómez Báez con el objetivo de ofrecer una nueva alternativa en la enseñanza del idioma francés incorporando de esta forma un nuevo material a la escasa bibliografía existente para esta especialidad. Se comprobó que los estudiantes poseen un pobre vocabulario en sentido general, así como dificultades con algunos elementos gramaticales particularmente con la conjugación de los verbos franceses en los distintos tiempos verbales, los adjetivos demostrativos  los pronombres posesivos y los adjetivos posesivos. La Marsellesa ofreció la posibilidad de trabajar no solo en aquellos aspectos de la gramática mencionados con anterioridad sino que permitió también enriquecer el vocabulario de los estudiantes, mejorar la ortografía, la pronunciación y contribuir a elevar la cultura general e integral de los futuros profesionales del turism

    GDP estimation for Barcelona and the Barcelona Metropolitan Area. Methodological improvement in the estimation of productivity dynamics with wage information

    Get PDF
    The Gross Domestic Product (GDP) is the most important macroeconomic magnitude of the economic accounting of a territory. In spite of its known limitations, it is a basic magnitude in knowing the sectoral structure of an economy; furthermore, its evolution is the indicator that best measures economic dynamics. The relevance of GDP is not limited to the knowledge of country or regional economies, but it is also key to the knowledge of local and metropolitan economies. In the case of Barcelona, the estimates made by the Technical Planning Office (GTP) of the Barcelona City Council available up to now start from the calculation for the base year 2011, calculating the values of the following years assuming that the effect of the agglomeration economies (characteristics of urban areas) does not vary from year to year. The availability of wages data from Barcelona, the Barcelona Metropolitan Area (AMB) and Catalonia from the Continuous Sample of Labour Lives (MCVL) allows us to relax this assumption, opening up the possibility of a methodological improvement in which the effect of agglomeration is picked up by the wage differentials between sectors and territorial areas registered every year. The aim of this paper is, therefore, to methodologically improve the calculation of the GDP of Barcelona and the AMB with the introduction of information on wage levels as indicators of productivity. The results achieved with this methodological improvement show a high correlation with the data so far prepared by the GTP, both for Barcelona and for the AMB, so that the methodology used here is validated. The implication of these results is quite significant: the wage differentials between territorial areas would be reflecting differences in the levels of productivity. To our understanding, these are very relevant results that may be of considerable interest for urban economic statistics, as they allow a more up-to-date estimate of municipal GDP (with an annual frequency) and with a significant degree of reliability

    Making the case for an International Decade of Radiocarbon

    Get PDF
    Radiocarbon (14C) is a critical tool for understanding the global carbon cycle. During the Anthropocene, two new processes influenced 14C in atmospheric, land and ocean carbon reservoirs. First, 14C-free carbon derived from fossil fuel burning has diluted 14C, at rates that have accelerated with time. Second, 'bomb' 14C produced by atmospheric nuclear weapon tests in the mid-twentieth century provided a global isotope tracer that is used to constrain rates of air-sea gas exchange, carbon turnover, large-scale atmospheric and ocean transport, and other key C cycle processes. As we write, the 14C/12C ratio of atmospheric CO2 is dropping below pre-industrial levels, and the rate of decline in the future will depend on global fossil fuel use and net exchange of bomb 14C between the atmosphere, ocean and land. This milestone coincides with a rapid increase in 14C measurement capacity worldwide. Leveraging future 14C measurements to understand processes and test models requires coordinated international effort-a 'decade of radiocarbon' with multiple goals: (i) filling observational gaps using archives, (ii) building and sustaining observation networks to increase measurement density across carbon reservoirs, (iii) developing databases, synthesis and modelling tools and (iv) establishing metrics for identifying and verifying changes in carbon sources and sinks. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'

    Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin

    Get PDF
    High-latitude northern rivers export globally significant quantities of dissolved organic carbon (DOC) to the Arctic Ocean. Climate change, and its associated impacts on hydrology and potential mobilization of ancient organic matter from permafrost, is likely to modify the flux, composition, and thus biogeochemical cycling and fate of exported DOC in the Arctic. This study examined DOC concentration and the composition of dissolved organic matter (DOM) across the hydrograph in Siberia's Kolyma River, with a particular focus on the spring freshet period when the majority of the annual DOC load is exported. The composition of DOM within the Kolyma basin was characterized using absorbance-derived measurements (absorbance coefficienta330, specific UV absorbance (SUVA254), and spectral slope ratio SR) and fluorescence spectroscopy (fluorescence index and excitation-emission matrices (EEMs)), including parallel factor analyses of EEMs. Increased surface runoff during the spring freshet led to DOM optical properties indicative of terrestrial soil inputs with high humic-like fluorescence, SUVA254, and low SRand fluorescence index (FI). Under-ice waters, in contrast, displayed opposing trends in optical properties representing less aromatic, lower molecular weight DOM. We demonstrate that substantial losses of DOC can occur via biological (∼30% over 28 days) and photochemical pathways (>29% over 14 days), particularly in samples collected during the spring freshet. The emerging view is therefore that of a more dynamic and labile carbon pool than previously thought, where DOM composition plays a fundamental role in controlling the fate and removal of DOC at a pan-Arctic scale

    Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

    Get PDF
    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a wellcharacterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 mu m diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 angstrom ngstrom were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.11Ysciescopu

    Mapping protein dynamics at high spatial resolution with temperature-jump X-ray crystallography

    Get PDF
    温度による酵素の構造変化を分子動画撮影 様々な生体高分子のダイナミクスを決定する新たな方法論. 京都大学プレスリリース. 2023-09-19.Understanding and controlling protein motion at atomic resolution is a hallmark challenge for structural biologists and protein engineers because conformational dynamics are essential for complex functions such as enzyme catalysis and allosteric regulation. Time-resolved crystallography offers a window into protein motions, yet without a universal perturbation to initiate conformational changes the method has been limited in scope. Here we couple a solvent-based temperature jump with time-resolved crystallography to visualize structural motions in lysozyme, a dynamic enzyme. We observed widespread atomic vibrations on the nanosecond timescale, which evolve on the submillisecond timescale into localized structural fluctuations that are coupled to the active site. An orthogonal perturbation to the enzyme, inhibitor binding, altered these dynamics by blocking key motions that allow energy to dissipate from vibrations into functional movements linked to the catalytic cycle. Because temperature jump is a universal method for perturbing molecular motion, the method demonstrated here is broadly applicable for studying protein dynamics

    Mitochondrial protein import

    Get PDF
    corecore