2,613 research outputs found

    Endogenous circannual rhythm in LH secretion: insight from signal analysis coupled with mathematical modelling

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    In sheep as in many vertebrates, the seasonal pattern of reproduction is timed by the annual photoperiodic cycle, characterized by seasonal changes in the daylength. The photoperiodic information is translated into a circadian profile of melatonin secretion. After multiple neuronal relays (within the hypothalamus), melatonin impacts GnRH (gonadotrophin releasing hormone) secretion that in turn controls ovarian cyclicity. The pattern of GnRH secretion is mirrored into that of LH (luteinizing hormone) secretion, whose plasmatic level can be easily measured. We addressed the question of whether there exists an endogenous circannual rhythm in a tropical sheep population that exhibits clear seasonal ovarian activity when ewes are subjected to temperate latitudes. We based our analysis on LH time series collected in the course of 3 years from ewes subjected to a constant photoperiodic regime. Due to intra- and inter- animal variability and unequal sampling times, the existence of an endogenous rhythm is not straightforward. We have used time-frequency signal processing methods to extract hidden rhythms from the data. To further investigate the LF (low frequency) and HF (high frequency) components of the signals, we have designed a mathematical model of LH plasmatic level accounting for the effect of experimental sampling times. The model enables us to confirm the existence of an endogenous circannual rhythm, to investigate the action mechanism of photoperiod on the pulsatile pattern of LH secretion (control of the interpulse interval) and to conclude that the HF component is mainly due to the experimental sampling protocol

    Huertos infantiles con musgo de Madagascar en régimen de perfeccionamiento activo para entrega intracomunitaria

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    El objetivo de este proyecto es asesorar a la empresa francesa “Garden & the City” a abrir un nuevo mercado en Bélgica. Con ese fin creamos una consultoría, Guiar & Meclaire Export Asociados, cuyo objeto social se puede resumir en asesoramiento e intermediación en comercio internacional. La operación consiste en comercializar unos huertos infantiles fabricados por la compañía francesa en la parte francófona de Bélgica, más concretamente en Thuin Gozée. Nuestra intervención suple las carencias exportadoras de la compañía francesa y lo hace a través de un contrato de consultoría y de agencia comercial. Hemos realizado un estudio de mercado en el país de destino y los hemos asesorado en temas de fiscalidad, transporte, de financiación y de comercialización. Además, hemos enriquecido el proceso productivo incluyendo una importación de musgo desde Madagascar en régimen de perfeccionamiento activo (RPA) para ser añadido en el producto con el fin de ahorrar costes a nuestro cliente

    DynPeak : An algorithm for pulse detection and frequency analysis in hormonal time series

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    The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedback exerted on the pituitary level. Hence, there is a real need for robust IPI detection algorithms. In this article, we present an algorithm for the monitoring of LH pulse frequency, basing ourselves both on the available endocrinological knowledge on LH pulse (shape and duration with respect to the frequency regime) and synthetic LH data generated by a simple model. We make use of synthetic data to make clear some basic notions underlying our algorithmic choices. We focus on explaining how the process of sampling affects drastically the original pattern of secretion, and especially the amplitude of the detectable pulses. We then describe the algorithm in details and perform it on different sets of both synthetic and experimental LH time series. We further comment on how to diagnose possible outliers from the series of IPIs which is the main output of the algorithm.Comment: Nombre de pages : 35 ; Nombre de figures : 16 ; Nombre de tableaux :

    Evaluación de los elementos de la comunicación interna en el personal administrativo de la Marina de Guerra. Callao. 2021

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    La presente investigación tiene como título “Evaluación de los elementos de la comunicación interna en el personal administrativo de la Marina de Guerra. Callao. 2021”, tuve como objetivo principal, Interpretar el nivel de evaluación de los elementos de la comunicación interna en el personal administrativo de la Marina de Guerra – Callao, 2021. La investigación corresponde al tipo aplicado, con un enfoque cuantitativo, con un nivel de investigación descriptivo simple, con un diseño no experimental. La recolección de la información fue a la Marina de Guerra del Perú, direccionada al área administrativa, con una muestra censal con un total de 102 personas. El instrumento que se empleo fue cuestionario de preguntas, lo cual fue realizado vía Google formulario, que detallo 18 preguntas que cumplieron con la validez del 100% y confiabilidad mediante el coeficiente de “Alfa de Cron Bach” con 0.88. Los resultados que se consiguieron con la encuesta fueron procesados en el programa estadístico SPSS versión 25. El objetivo general de la investigación dio como resultado que 1.9% no manejan los elementos de la comunicación interna, el 6.5% manifiesta que casi nunca, el 26.4% de los trabajadores encuestados aseguran a veces, el 44.1% de los trabajadores manejan los elementos de la comunicación interna aseguraron “Casi siempre”. Mientras que el 21.1% confirman que “siempre”. Se concluye que las herramientas utilizadas en la Institución, tuvieron gran relevancia para que los mensajes enviados tengan gran aceptación por parte del público interno, y, de esta forma, lograr que en la entidad pueda haber un buen desempeño, de acuerdo a los objetivos planteados por la empresa

    The Earth as an extrasolar transiting planet - II: HARPS and UVES detection of water vapor, biogenic O2_2, and O3_3

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    The atmospheric composition of transiting exoplanets can be characterized during transit by spectroscopy. For the transit of an Earth twin, models predict that biogenic O2O_2 and O3O_3 should be detectable, as well as water vapour, a molecule linked to habitability as we know it on Earth. The aim is to measure the Earth radius versus wavelength λ\lambda - or the atmosphere thickness h(λ)h(\lambda) - at the highest spectral resolution available to fully characterize the signature of Earth seen as a transiting exoplanet. We present observations of the Moon eclipse of 21-12-2010. Seen from the Moon, the Earth eclipses the Sun and opens access to the Earth atmosphere transmission spectrum. We used HARPS and UVES spectrographs to take penumbra and umbra high-resolution spectra from 3100 to 10400 Ang. A change of the quantity of water vapour above the telescope compromised the quality of the UVES data. We corrected for this effect in the data processing. We analyzed the data by 3 different methods. The 1st method is based on the analysis of pairs of penumbra spectra. The 2nd makes use of a single penumbra spectrum, and the 3rd of all penumbra and umbra spectra. Profiles h(λ)h(\lambda) are obtained with the three methods for both instruments. The 1st method gives the best result, in agreement with a model. The second method seems to be more sensitive to the Doppler shift of solar spectral lines with respect to the telluric lines. The 3rd method makes use of umbra spectra which bias the result, but it can be corrected for this a posteriori from results with the first method. The 3 methods clearly show the spectral signature of the Rayleigh scattering in the Earth atmosphere and the bands of H2_2O, O2_2, and O3_3. Sodium is detected. Assuming no atmospheric perturbations, we show that the E-ELT is theoretically able to detect the O2O_2 A-band in 8~h of integration for an Earth twin at 10pc.Comment: Final version accepted for publication in A&A - 21 pages, 27 figures. Abstract above slightly shortened wrt the original. The ArXiv version has low resolution figures, but a version with full resolution figures is available here: http://www.obs-hp.fr/~larnold/publi_to_download/eclipse2010_AA_v5_final.pd

    Apport scientifique, éducatif et ludique de l’espace Blaise Pascal au muséum Henri-Lecoq de Clermont-Ferrand

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    Les responsables chargés de la mise en place d’un espace éducatif et ludique consacré aux travaux de Blaise Pascal dressent un premier bilan de cette expérience en montrant l’intérêt de ce projet – mené par une équipe pluridisciplinaire – dont l’objectif était d’associer explications et apports scientifiques, jeu et pédagogie et qui, en définitive, a contribué au renouvellement des outils et méthodes de travail du service éducatif du musée

    The Earth as an extrasolar transiting planet: Earth's atmospheric composition and thickness revealed by Lunar eclipse observations

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    An important goal within the quest for detecting an Earth-like extrasolar planet, will be to identify atmospheric gaseous bio-signatures. Observations of the light transmitted through the Earth's atmosphere, as for an extrasolar planet, will be the first step for future comparisons. We have completed observations of the Earth during a Lunar eclipse, a unique situation similar to that of a transiting planet. We aim at showing what species could be detected in its atmosphere at optical wavelengths, where a lot of photons are available in the masked stellar light. We present observations of the 2008 August 16 Moon eclipse performed with the SOPHIE spectrograph at the Observatoire de Haute-Provence. Locating the spectrograph fibers in the penumbra of the eclipse, the Moon irradiance is then a mix of direct, unabsorbed Sun light and solar light that has passed through the Earth's limb. This mixture essentially reproduces what is recorded during the transit of an extrasolar planet. We report here the clear detection of several Earth atmospheric compounds in the transmission spectra, such as ozone, molecular oxygen, and neutral sodium as well as molecular nitrogen and oxygen through the Rayleigh signature. Moreover, we present a method that allows us to derive the thickness of the atmosphere versus the wavelength for penumbra eclipse observations. We quantitatively evaluate the altitude at which the atmosphere becomes transparent for important species like molecular oxygen and ozone, two species thought to be tightly linked to the presence of life. The molecular detections presented here are an encouraging first attempt, necessary to better prepare for the future of extremely-large telescopes and transiting Earth-like planets. Instruments like SOPHIE will be mandatory when characterizing the atmospheres of transiting Earth-like planets from the ground and searching for bio-marker signatures.Comment: 15 pages, 14 figures, 2 tables. Accepted for publication in Astronomy and Astrophysic

    Angular analysis of B0→D∗−D∗+s with D∗+s→D+sγ decays

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    The first full angular analysis of the B0→D∗−D∗+s decay is performed using 6 fb−1 of pp collision data collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The D∗+s→D+sγ and D*− → D¯¯¯¯0π− vector meson decays are used with the subsequent D+s → K+K−π+ and D¯¯¯¯0 → K+π− decays. All helicity amplitudes and phases are measured, and the longitudinal polarisation fraction is determined to be fL = 0.578 ± 0.010 ± 0.011 with world-best precision, where the first uncertainty is statistical and the second is systematic. The pattern of helicity amplitude magnitudes is found to align with expectations from quark-helicity conservation in B decays. The ratio of branching fractions [ℬ(B0→D∗−D∗+s) × ℬ(D∗+s→D+sγ)]/ℬ(B0 → D*−D+s) is measured to be 2.045 ± 0.022 ± 0.071 with world-best precision. In addition, the first observation of the Cabibbo-suppressed Bs → D*−D+s decay is made with a significance of seven standard deviations. The branching fraction ratio ℬ(Bs → D*−D+s)/ℬ(B0 → D*−D+s) is measured to be 0.049 ± 0.006 ± 0.003 ± 0.002, where the third uncertainty is due to limited knowledge of the ratio of fragmentation fractionsS
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