561 research outputs found

    Adherence to 24-Hour Movement Guidelines among Spanish Adolescents: Differences between Boys and Girls

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    Background: The 24-Hour Movement Guidelines for adolescents recommend >= 60 min/day of moderate-to-vigorous physical activity (PA), <= 2 h/day of screen time, and 8-10 h/day of sleep. Since little information is available on the 24-Hour Movement Guidelines in Spanish adolescents, this study aims to estimate the proportion of Spanish adolescents meeting individual and combinations of these 24-Hour Movement Guidelines. Moreover, another aim of this study is to examine gender differences in compliance with 24-Hour Movement Guidelines. Methods: A final sample of 1465 Spanish adolescents (44.50% girls; 13.08 +/- 0.86) participated in this cross-sectional study. The 24-Hour Movement Guidelines were measured during weekdays and the weekend days by self-reported questionnaires. Results: Although most adolescents met sleep duration guidelines (81.3%), only 38% and 15.8% met physical activity and screen time guidelines, respectively. Only 5.4% of these adolescents met all three 24-Hour Movement Guidelines, whereas 10.2% of this sample did not meet any of these guidelines. Although boys reported greater compliance with physical activity recommendations and girls with screen time recommendations, no significant gender differences were found in the compliance of all three 24-Hour Movement Guidelines. Conclusion: Given that 94.4% of Spanish adolescents did not meet 24-Hour Movement Guidelines, promoting all these three movement behaviours in both boys and girls is an urgent public health priority

    Symbolic dynamical unfolding of spike-adding bifurcations in chaotic neuron models

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    We characterize the systematic changes in the topological structure of chaotic attractors that occur as spike-adding and homoclinic bifurcations are encountered in the slow-fast dynamics of neuron models. This phenomenon is detailed in the simple Hindmarsh-Rose neuron model, where we show that the unstable periodic orbits appearing after each spike-adding bifurcation are associated with specific symbolic sequences in the canonical symbolic encoding of the dynamics of the system. This allows us to understand how these bifurcations modify the internal structure of the chaotic attractors

    Influence of different factors on relative air humidity in Zaragoza, Spain

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    In this study, the spatial patterns of relative air humidity and its relation to urban, geographical and meteorological factors in the city of Zaragoza (Spain) is discussed. We created a relative humidity database by means of 32 urban transects. Data were taken on different days and with different weather types. This data set was used to map the mean spatial distribution of urban dry island (UDI). Using stepwise multiple regression analysis and Landsat ETM+ images the relationships between mean UDI and the main geographic-urban factors: topography, land cover, and surface reflectivity, have been analyzed. Different spatial patterns of UDI were determined using Principal Component Analysis (PCA) (Varimax rotation). The three components extracted accounted for 91% of the total variance. PC1 accounted for the most general patterns (similar to mean UDI); PC2 showed a shift of dry areas to the SE and PC3 a shift to NW. Using data on wind direction in Zaragoza, we have found that the displacement of dry areas to the SE (PC 2) was greater during NW winds while the shift to the NW (PC 3) was produced mainly by SE winds

    Excavaciones en el conjunto funerario de época hispano-visigoda de la Cabeza (La Cabrera, Madrid)

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    La presencia visigoda en la actual Comunidad de Madrid está ampliamente constatada a través de las innumerables necrópolis conocidas. El pequeño conjunto funerario de la Cabeza, excavado con carácter de urgencia, ofrece una serie de características que le hacen particularmente interesante: número de tumbas, situación geográfica, ubicación topográfica, tipología del conjunto, etc. Tanto por su arquitectura funeraria como, y sobre todo, por el material hallado, hemos fechado el conjunto dentro del siglo VII

    Terminal Phosphanido Rhodium Complexes Mediating Catalytic P—P and P—C Bond Formation

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    Complexes with terminal phosphanido (M-PR2) functionalities are believed to be crucial intermediates in new catalytic processes involving the formation of P-P and P-C bonds. We showcase here the isolation and characterization of mononuclear phosphanide rhodium complexes ([RhTp(H)(PR2)L]) that result from the oxidative addition of secondary phosphanes, a reaction that was also explored computationally. These compounds are active catalysts for the dehydrocoupling of PHPh2 to Ph2P-PPh2. The hydrophosphination of dimethyl maleate and the unactivated olefin ethylene is also reported. Reliable evidence for the prominent role of mononuclear phosphanido rhodium species in these reactions is also provided.The generous financial support from MICINN/FEDER (Project CTQ2011-22516), Gobierno de Aragón/FSE (GA/FSE, Inorganic Molecular Architecture Group, E70), and NWO-CW (VICI project 016.122.613; BdB) is gratefully acknowledged. A.M.G. and A.L.S. thank Gobierno de Aragón and MEC, respectively, for fellowships.Peer reviewe

    Estudio comparativo de las características físicas del semen de ovino en el laboratorio de reproducción asistida de la Diputación de Córdoba

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    En el presente trabajo se ha realizado un estudio comparativo de las caracteristicas físicas (volumen y concentración) de semen procedente de las extracciones realizadas en el laboratorio de Reproducción Asistida de Pequeños Rumiantes (código comunitario ES-04-02-0C), ubicado en el Centro Agropecuario Provincial de la Diputación de Córdoba, durante los años 2003, 2004 y 2005. Estos trabajos se vienen desarrollando en el seno de los convenios de colaboración suscritos entre la institución cordobesa y las Asociaciones de Criadores de Ovinos Precoces, Merino y Lacaune, para la mejora genética de los rebaños de la provincia mediante el empleo de técnicas de inseminación artificial como medida de apoyo al desarrollo de los esquemas de selección de estas razas. Se realizó un análisis de varianza para la evaluación de la influencia de los efectos del año de extracción, la raza, la época de extracción y la interacción entre la raza y la época de extracción sobre el volumen y la concentración seminal

    Characterization of the UHI in Zaragoza (Spain) using a quality-controlled hourly sensor-based urban climate network

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    The study of the urban heat island (UHI) is of great importance in the context of climate change, where increasingly frequent and intense extreme thermal events will generate lethal effects in cities. In this work, we characterize the UHI of the urban area of Zaragoza (Spain) using a thermohygrometric network of hourly observatories composed of 21 sensors, from March 2015 to February 2021. Due to the diversity of urban spaces and the high volume of information (˜ 995, 000 observations), we performed an exhaustive quality control. Incorporating a synoptic analysis to better identify atmospheric situations not recorded by sensors. The results indicate that 1.6% of observations are removed, mainly due to outliers and hourly variability. We demonstrate that the UHI displays the classical center-periphery pattern with intensity values around 2 °C, but with variations due to the urban structure. We also observe seasonal UHI variations that intensify, especially in winter and autumn nights. Finally, this characterization confirms the differences in UHI intensity are due to their structural and climatic characteristics, which can ultimately guide the logical urban planning design of Zaragoza, and other Mediterranean-like cities with a similar urban environment

    Study of turbocharger shaft motion by means of non-invasive optical techniques: Application to the behaviour analysis in turbocharger lubrication failures

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    [EN] This paper presents a novel non-invasive technique to estimate the turbocharger shaft whirl motion. The aim of this article is to present a system for monitoring the shaft motion of a turbocharger, which will be used in turbocharger destructive testing. To achieve this, a camera and a light source were installed in a turbocharger test bench with a controlled lubrication circuit. An image recording methodology and a process algorithm have been developed, in order to estimate the shaft motion. This processing consists on differentiating specific zones of the image, in order to obtain their coordinates. Two reference points have been configured on the compressor side, which help to calculate the relative position of the shaft, avoiding the errors due to structural vibrations. Maximum eccentricity of the turbocharger has been determined and it has been compared with shaft motion when it is spinning in different conditions. A luminosity study has been also done, in order to improve the process and to obtain locus of shaft position in a picture exposition time period. The technique has been applied to diagnosis of a lubrication failure test and the main results will be presented in this article: like shaft motion figures; thermodynamic variables and pictures of the shaft while it is spinning at abnormal lubrication conditions. The measuring components used in this technique have the ability to withstand the catastrophic failure of the turbocharger in this type of test. © 2012 Elsevier Ltd.Pastor, JV.; Serrano, J.; Dolz, V.; López Hidalgo, M.; Bouffaud, F. (2012). Study of turbocharger shaft motion by means of non-invasive optical techniques: Application to the behaviour analysis in turbocharger lubrication failures. Mechanical Systems and Signal Processing. 32:292-305. doi:10.1016/j.ymssp.2012.04.020S2923053

    Hormonal responses to competition

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    S p o rts competitions have been employed to analy ze the influence of social confro n t ations on hormonal levels. Howeve r, results have been inconsistent. Seve ral va ri ables such as outcome, phy s i c a l exe rtion, mood and causal at t ri bution have been considered as important mediat o rs of this infl u e nc e. Our aim was to examine their role in the testosterone and cortisol responses to a real confro n t ation. To this end, twe l ve judoists who part i c i p ated in a competition between clubs we re studied. Results showed non significant diffe rences depending on outcome in hormones, physical exe rtion, mood and causal at t ri bution; only sat i s faction with the outcome being significant. Intere s t i n g ly, testoste rone response was positive ly associated with self-ap p raisal of perfo rmance and at t ri bution of outcome to personal effo rt. Cortisol response showed a ve ry consistent re l ationship with negat ive moo d. These findings support a clear association of competition-induced hormonal responses with cogni t ive and emotional aspects rather than with objective (outcome or physical exe rtion) ch a ra c t e ri stics of the situat i o n

    Analysis of sexual behaviour in male rabbits across successive tests leading to sexual exhaustion

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    [EN] Various parameters of sexual behaviour were studied in ten male rabbits daily tested with sexually receptive females (ovariectomized, given estradiol benzoate s.c. 5 µg/day). The aim of this study was to analyse rabbit sexual behaviour during successive tests leading to sexual exhaustion. We allowed copulation ad libitum and determined if sexual satiety was reached within a day and sexual exhaustion across several days. The pair was allowed to copulate freely until the male failed to show sexual interest in that female for 30 minutes. The female was then removed and replaced by another; this procedure was repeated using as many does as needed, until the male showed no interest in any female for 2 hours. Scent-marking (chinning) was also recorded, before and after the copulation test. This whole procedure was repeated daily until the male showed no sexual behaviour at all on a given day. Within a test, copulation ad libitum led to a gradual increase in the time interval between successive mounts and ejaculations, regardless of the day of testing. Such increments predicted that the buck was reaching sexual satiety. The "miss" rate (i.e., the proportion of mounts that did not culminate in ejaculation) significantly increased from a median of 25 on the first day to 55 on the last day of testing. The mean time to reach copulatory inactivity decreased from 4 hrs on the first day to 1 hr on the last day. The total number of ejaculations within a test decreased from an average of 22 to 6 (first vs last day, respectively) and the number of chin marks was reduced by 69% compared with pre-mating values, regardless of the day of testing. All bucks eventually stopped copulating after a variable number of days (range=2-15 days). We concluded that, following copulation ad libitum with several females, male rabbits reach sexual satiety (i.e., they are unable to continue copulating on the same day) and, after several days, they also attain sexual exhaustion, a state in which copulation is totally arrested for at least 24 hours. Some behavioural parameters can be used as reliable predictors that a buck is approaching sexual satiety and sexual exhaustion.Jimenez, P.; Serrano-Meneses, M.; Cuamatzi, E.; González-Mariscal, G.; González-Maris (2012). Analysis of sexual behaviour in male rabbits across successive tests leading to sexual exhaustion. World Rabbit Science. 20(1):13-23. doi:10.4995/wrs.2012.1034SWORD132320
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