2,115 research outputs found

    Mathematical tools for identifying the fetal response to physical exercise during pregnancy

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    In the applied mathematics literature there exist a significant number of tools that can reveal the interaction between mother and fetus during rest and also during and after exercise. These tools are based on techniques from a number of areas such as signal processing, time series analysis, neural networks, heart rate variability as well as dynamical systems and chaos. We will briefly review here some of these methods, concentrating on a method of extracting the fetal heart rate from the mixed maternal-fetal heart rate signal, that is based on phase space reconstructio

    Acute maternal exercise during the third trimester of pregnancy, influence on foetal heart rate = Ejercicio físico durante el tercer trimestre de embarazo, influencia en la frecuencia cardiaca fetal

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    A substantial amount of research has investigated the influence of physical exercise during pregnancy on certain maternal and foetal parameters. Regarding the behaviour of the foetal heart rate (FHR) during the maternal exercise certain controversy exists; as several investigations have studied this parameter obtaining varied results. To test the hypotheses that the foetal heart rate (FHR) increases during maternal exercise, performed on a static bicycle during the third trimester. To know if the magnitude of the increase is related to gestational age or parity. This research involved a collaboration with the Gynaecology and Obstetrics Service of “Severo Ochoa” Hospital (Madrid) and Universidad Politécnica de Madrid (UPM). The approval of the Committee of Investigation as well as of the Ethical Commission of the Hospital was obtained. Twenty healthy pregnant women have been studied, in the last trimester. No women showed any medical complications in their pregnancy or contraindications for the practice of physical exercise. Informed consent was obtained. The exercise protocol consisted in the first part (rest), followed by a session of 20 minutes of moderate work (static bicycle exercise) and then rest until the FHR returned to the pre-exercise levels. Data for the evaluation of the FHR was obtained using an Electronic Foetal Monitor, Philips FM 20; and an Accurex Plus, Polar Electro OY was used for the control of the maternal heart rate. The clinical history of the pregnant women provided data about medical and personal factors. For the statistical analysis, Pearson correlation and Student’s t test for unpaired data were used. Our results show increases (11 - 36 beats/min, mean= 24 beats/min) of the FHR in all the studied cases. The gestational age shows no correlation with increments of FHR (Pearson 0.06) and there are larger increments of FHR in secundigravid (mean=152 ± 6.0 beats/min) than in primigravid (mean=147 ± 4.6 beats/min). Maternal aerobic and moderate exercise developing during last trimester increments FHR without harmful effects. These increments do not depend on the maternal age. Parity has influence on the level of increments of the FHR. Una cantidad importante de investigaciones han valorado la influencia del ejercicio físico durante el embarazo en ciertos parámetros fetales. En relación al comportamiento de la frecuencia cardiaca fetal (FCF) durante la realización del ejercicio existe cierta controversia, muchas investigaciones han estudiado este parámetro con resultados variados. El objetivo de este estudio fue comprobar la hipótesis de un aumento de la FCF durante la realización de ejercicio en bicicleta estática en el tercer trimestre de embarazo. También conocer si esos aumentos se relacionan con la edad gestacional o la paridad de la gestante. Este estudio se ha desarrollado mediante una colaboración entre el Servicio de Ginecología y Obstetricia del Hospital Severo Ochoa de Leganés y la Universidad Politécnica de Madrid. Se obtuvo la aprobación del Comité de Investigación así como de la Comisión Ética. Fueron estudiadas 20 gestantes en el último trimestre, sin complicaciones ni contraindicaciones médicas para el ejercicio, cada mujer firmó un consentimiento informado. El protocolo de ejercicio consistió en una primera parte de reposo, una sesión de 20 minutos de trabajo moderado en bicicleta estática y el reposo final con retorno a los niveles normales de FCF. Los datos correspondientes a la FCF se obtuvieron por medio de un Monitor Fetal Electrónico Philips FM 20, y un pulsómetro Accurex Plus, Polar Electro OY, fue usado para el control de la frecuencia cardiaca materna. La historia clínica de cada gestante aportó datos relativos a características médicas y personales. Para el análisis estadístico se utilizaron mecanismos descriptivos, el índice de correlación de Pearson y la t de Student para comparación de medias. Nuestros resultados muestran aumentos de la FCF de 11-36 lat/min (media de 24 lat/min). Los días de gestación no presentaron una correlación positiva con el nivel de los incrementos (Pearson 0.06). Hubo mayores aumentos en gestantes secundigrávidas (media=152 ± 6.0 lat/min) que en primigrávidas (media=147 ± 4.6 lat/min). El ejercicio aeróbico y moderado materno desarrollado durante el tercer trimestre de embarazo incrementa la FCF sin efectos perjudiciales. Los aumentos no dependen de la edad gestacional de la madre. La paridad de la gestante tiene influencia en el nivel de los incrementos

    Charge Conjugation from Space-Time Inversion

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    We show that the CPT group of the Dirac field emerges naturally from the PT and P (or T) subgroups of the Lorentz group.Comment: 4 pages, no figure

    A Megacam Survey of Outer Halo Satellites. IV. Two foreground populations possibly associated with the Monoceros substructure in the direction of NGC2419 and Koposov2

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    The origin of the Galactic halo stellar structure known as the Monoceros ring is still under debate. In this work, we study that halo substructure using deep CFHT wide-field photometry obtained for the globular clusters NGC2419 and Koposov2, where the presence of Monoceros becomes significant because of their coincident projected position. Using Sloan Digital Sky Survey photometry and spectroscopy in the area surrounding these globulars and beyond, where the same Monoceros population is detected, we conclude that a second feature, not likely to be associated with Milky Way disk stars along the line-of-sight, is present as foreground population. Our analysis suggests that the Monoceros ring might be composed of an old stellar population of age t ~ 9Gyr and a new component ~ 4Gyr younger at the same heliocentric distance. Alternatively, this detection might be associated with a second wrap of Monoceros in that direction of the sky and also indicate a metallicity spread in the ring. The detection of such a low-density feature in other sections of this halo substructure will shed light on its nature.Comment: 10 pages, 10 figures, accepted for publication in Ap

    Hearts of Darkness: the inside out probing of black holes

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    Classical black holes shield us from the singularities that inevitably appear in general relativity. Singularity regularization being one of the main landmarks for a successful theory of quantum gravity, quantum black holes are not obliged to hide their inner core from the outside world. Notwithstanding the aforesaid, it is often implicitly assumed that quantum gravity effects must remain confined to black hole interiors. In this essay, we argue in the opposite direction, discussing theoretical evidence for the existence of strong correlations between the physics inside and outside nonsingular black holes. We conclude that astronomical tests of the surroundings of black holes can provide invaluable information about their so-far unexplored interiors

    Bone Marrow Transplantation Reproduces the Tristetraprolin-Deficiency Syndrome in Recombination Activating Gene-2 (-/-) Mice: Evidence That Monocyte/Macrophage Progenitors May Be Responsible for TNFα Overproduction

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    Tristetraprolin-deficient [TTP (-/-)] mice exhibit a complex syndrome of myeloid hyperplasia, cachexia, dermatitis, autoimmunity, and erosive arthritis. Virtually the entire syndrome can be prevented by the repeated injection of anti-TNFα antibodies (Taylor, G.A., E. Carballo, D.M. Lee, W.S. Lai, M.J. Thompson, D.D. Patel, D.I. Schenkman, G.S. Gilkeson, H.E. Broxmeyer, B.F. Haynes, and P.J. Blackshear. 1996. Immunity. 4:445–454). In the present study, we transplanted bone marrow from TTP (-/-) and (+/+) mice into recombination activating gene-2 (-/-) mice. After a lag period of several months, marrow transplantation from the (-/-) but not the (+/+) mice resulted in the full syndrome associated with TTP deficiency, suggesting that hematopoietic progenitors are responsible for the development of the syndrome. Western blot analysis of supernatants from cultured TTP-deficient macrophages derived from the peritoneal cavity or bone marrow of adult TTP (-/-) mice, or from fetal liver, demonstrated an increased accumulation of TNFα after stimulation with LPS compared to control cells, and also increased accumulation of TNFα mRNA. This difference was not observed with cultured fibroblasts or T and B lymphocytes. These data suggest that macrophages are among the cells responsible for the effective excess of TNFα that leads to the pathology reported in TTP (-/-) animals, and that macrophage progenitors may be involved in the transplantability of this syndrome

    On the origin of the X-ray emission from a narrow-line radioquasar at z>1

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    We present new XMM-Newton X-ray observations of the z=1.246 narrow-line radioquasar RX J1011.2+5545 serendipitously discovered by ROSAT. The flat X-ray spectrum previously measured by ROSAT and ASCA is shown to be the result of a steep Gamma~1.8 power law spectrum seen through a moderate intrinsic absorbing column NH~4E21 cm^-2. The position of the X-ray source is entirely coincident with the nucleus of the radio source that we have resolved in new sensitive VLA observations at 3.6 and 6 cm, implying that scattering in the radio lobes is not responsible for the bulk of X-ray emission. In the EPIC pn image, a faint patch of X-ray emission is apparent 14'' to the NE of the main X-ray source. The former is positionally coincident with an apparently extended optical object with R~21.9, but there is no associated radio emission, thus ruling out the possibility that this represents a hotspot in a jet emanating from the primary X-ray source. No reflection features are detected in the X-ray spectrum of the narrow-line radioquasar, although an Fe line with equivalent width of up to 600 eV cannot be ruled out.Comment: 7 pages, 6 figures, MNRAS in the pres

    Opening the Pandora's box at the core of black holes

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    We present a geometric classification of all spherically symmetric spacetimes that could result from singularity regularization, using a kinematic construction that is both exhaustive and oblivious to the dynamics of the fields involved. Due to the minimal geometric assumptions underlying it, this classification encompasses virtually all modified gravity theories, and any theory of quantum gravity in which an effective description in terms of an effective metric is available. The first noteworthy conclusion of our analysis is that the number of independent classes of geometries that can be constructed is remarkably limited, with no more than a handful of qualitatively different possibilities. But our most remarkable result is that this catalogue of possibilities clearly demonstrates that the degree of internal consistency and the strength of deviations with respect to general relativity are strongly, and positively, correlated. Hence, either quantum fluctuations of spacetime come to the rescue and solve these internal consistency issues, or singularity regularization will percolate to macroscopic (near-horizon) scales, radically changing our understanding of black holes and opening new opportunities to test quantum gravity
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