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Search Results: 1 - 10 of 87772 matches for " Fermin I. Milagro "
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Maternal Methyl Donors Supplementation during Lactation Prevents the Hyperhomocysteinemia Induced by a High-Fat-Sucrose Intake by Dams
Paul Cordero,Fermin I. Milagro,Javier Campion,J. Alfredo Martinez
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms141224422
Abstract: Maternal perinatal nutrition may program offspring metabolic features. Epigenetic regulation is one of the candidate mechanisms that may be affected by maternal dietary methyl donors intake as potential controllers of plasma homocysteine levels. Thirty-two Wistar pregnant rats were randomly assigned into four dietary groups during lactation: control, control supplemented with methyl donors, high-fat-sucrose and high-fat-sucrose supplemented with methyl donors. Physiological outcomes in the offspring were measured, including hepatic mRNA expression and global DNA methylation after weaning. The newborns whose mothers were fed the obesogenic diet were heavier longer and with a higher adiposity and intrahepatic fat content. Interestingly, increased levels of plasma homocysteine induced by the maternal high-fat-sucrose dietary intake were prevented in both sexes by maternal methyl donors supplementation. Total hepatic DNA methylation decreased in females due to maternal methyl donors administration, while Dnmt3a hepatic mRNA levels decreased accompanying the high-fat-sucrose consumption. Furthermore, a negative association between Dnmt3a liver mRNA levels and plasma homocysteine concentrations was found. Maternal high-fat-sucrose diet during lactation could program offspring obesity features, while methyl donors supplementation prevented the onset of high hyperhomocysteinemia. Maternal dietary intake also affected hepatic DNA methylation metabolism, which could be linked with the regulation of the methionine-homocysteine cycle.
Infinite-dimensional representations of the rotation group and Dirac's monopole problem
Alexander I. Nesterov,Fermin Aceves de la Cruz
Mathematics , 2005, DOI: 10.1063/1.2830430
Abstract: Within the context of infinite-dimensional representations of the rotation group the Dirac monopole problem is studied in details. Irreducible infinite-dimensional representations, being realized in the indefinite metric Hilbert space, are given by linear unbounded operators in infinite-dimensional topological spaces, supplied with a weak topology and associated weak convergence. We argue that an arbitrary magnetic charge is allowed, and the Dirac quantization condition can be replaced by a generalized quantization rule yielding a new quantum number, the so-called topological spin, which is related to the weight of the Dirac string.
Status of the Milagro Gamma Ray Observatory
The Milagro Collaboration
Physics , 2001,
Abstract: The Milagro Gamma Ray Observatory, located at an altitude of 8,600 feet in the Jemez Mountains of New Mexico, is the world's first large-area water Cherenkov detector capable of continuously monitoring the entire sky for sources of TeV gamma rays. It is uniquely capable of searching for transient sources of VHE gamma rays. The core of the detector is a 60m x 80m x 8m pond instrumented with 723 PMTs deployed in two layers. This part of the detector is complete and has operated continuously since Jan. 2000. Initial studies including searches for gamma-ray sources are ongoing, and preliminary results are available. The final stage of construction is under way. We are deploying 170 auxiliary "outrigger" water Cherenkov detectors in an area of 40,000 square-meters surrounding the pond, which will significantly enhance our ability to reject background and more accurately reconstruct the gamma-ray direction and energy. In addition, we are lowering the energy threshold of the detector by using custom processing to enable real-time intelligent triggering. The lower energy threshold will significantly increase our sensitivity to gamma-ray sources, and in particular to sources of cosmological origin, such as GRBs, where the higher energy gamma-rays have sizable attenuation due to the interaction with the intergalactic infra-red light.
Observation of TeV Gamma Rays from the Crab Nebula with Milagro Using a New Background Rejection Technique
The Milagro Collaboration
Physics , 2003, DOI: 10.1086/377498
Abstract: The recent advances in TeV gamma-ray astronomy are largely the result of the ability to differentiate between extensive air showers generated by gamma rays and hadronic cosmic rays. Air Cherenkov telescopes have developed and perfected the "imaging" technique over the past several decades. However until now no background rejection method has been successfully used in an air shower array to detect a source of TeV gamma rays. We report on a method to differentiate hadronic air showers from electromagnetic air showers in the Milagro gamma ray observatory, based on the ability to detect the energetic particles in an extensive air shower. The technique is used to detect TeV emission from the Crab nebula. The flux from the Crab is estimated to be 2.68(+-0.42stat +- 1.4sys) x10^{-7} (E/1TeV)^{-2.59} m^{-2} s^{-1} TeV^{-1}, where the spectral index is assumed to be as given by the HEGRA collaboration.
Site-specific circadian expression of leptin and its receptor in human adipose tissue Expresión circadiana específica de la localización de leptina y su receptor en tejido adiposo humano
P. Gómez Abellán,C. Gómez Santos,J. A. Madrid,F. I. Milagro
Nutrición Hospitalaria , 2011,
Abstract: Introduction: Circadian variability of circulating leptin levels has been well established over the last decade. However, the circadian behavior of leptin in human adipose tissue remains unknown. This also applies to the soluble leptin receptor. Objective: We investigated the ex vivo circadian behavior of leptin and its receptor expression in human adipose tissue (AT). Subjects and methods: Visceral and subcutaneous abdominal AT biopsies (n = 6) were obtained from morbid obese women (BMI ≥ 40 kg/m2). Anthropometric variables and fasting plasma glucose, leptin, lipids and lipoprotein concentrations were determined. In order to investigate rhythmic expression pattern of leptin and its receptor, AT explants were cultured during 24-h and gene expression was analyzed at the following times: 08:00, 14:00, 20:00, 02:00 h, using quantitative real-time PCR. Results: Leptin expression showed an oscillatory pattern that was consistent with circadian rhythm in cultured AT. Similar patterns were noted for the leptin receptor. Leptin showed its achrophase (maximum expression) during the night, which might be associated to a lower degree of fat accumulation and higher mobilization. When comparing both fat depots, visceral AT anticipated its expression towards afternoon and evening hours. Interestingly, leptin plasma values were associated with decreased amplitude of LEP rhythm. This association was lost when adjusting for waist circumference. Conclusion: Circadian rhythmicity has been demonstrated in leptin and its receptor in human AT cultures in a site-specific manner. This new knowledge paves the way for a better understanding of the autocrine/paracrine role of leptin in human AT. Introducción: La variabilidad circadiana de los niveles de leptina circulante se ha establecido en la última década, pero actualmente se desconoce el comportamiento circadiano de leptina y su receptor en tejido adiposo (TA) humano. Objetivo: Investigar si existe un comportamiento circadiano en la expresión de leptina y su receptor en TA humano. Sujetos y métodos: Se obtuvieron biopsias de TA visceral y subcutáneo abdominal de mujeres (n = 6) obesas mórbidas (IMC ≥ 40 kg/m2). Se determinaron variables antropométricas y concentraciones plasmáticas en ayunas de glucosa, leptina, lípidos y lipoproteínas. Para investigar los patrones de expresión rítmica de los genes, se cultivaron explantes de TA durante 24-h y se analizó la expresión génica a diferentes horas: 08:00, 14:00, 20:00, 02:00 h, usando PCR cuantitativa a tiempo real. Resultados: La leptina mostró un patrón oscilatorio de expresión
(0,2) String Compactifications: The Higgs Mechanism
Fermin Aldabe
Physics , 1995,
Abstract: We present the Higgs mechanism in (0,2) compactifications. The existence of a vector bundle data duality (VBDD) in $(0,2)$ compactifications which is present at the Landau-Ginzburg point allows us to connect in a smooth manner theories with different gauge groups with the same base manifold and same number of effective generations. As we move along the Kahler moduli space of the theories with $E_6$ gauge group, some of the gauginos pick up masses and break the gauge group to $SO(10)$ or $SU(5)$.
Quantum Solitons Lead to Yukawa Coupling
Fermin Aldabe
Physics , 1995,
Abstract: Recently, it was shown that zero modes in semiclassical soliton models do not lead to Yukawa couplings. We show that taking into account the contributions of the quantum soliton into the renormalization scheme, which cannot be done in semiclassical treatments, leads to a Yukawa coupling. A similar analysis should be possible for the Skyrmion, renewing the hope, that this model will lead to a correct description of hadron physics.
Can Plane Wave Modes be Physical Modes in Soliton Models?
Fermin Aldabe
Physics , 1995, DOI: 10.1016/0370-2693(95)00385-X
Abstract: I show that plane waves may not be used as asymptotic states in soliton models because they describe unphysical states. When asymptotic states are taken to be physical there is no T-matrix of $\cO(1)$.
Brownian Motion of Solitons in the $Φ^4$ Model
Fermin Aldabe
Physics , 1995, DOI: 10.1142/S0217979296000519
Abstract: We derive an expression for the correlation function of the random force on a soliton which is consistent with the constraints needed to integrate out the zero modes which appear due to the broken translational symmetry of the soliton solution. It is shown that when the constraint does not commute with the operator which defines the correlation function, i.e. when the operator is not physical, only low frequency phonons contributions may be considered. On the contrary, when the correlation function of the random force on the soliton is constructed with physical operators one may also include in a correct manner the contributions from the optical phonons.
Collective Coordinates and the Absence of Yukawa Coupling in the Classical Skyrme Model
Fermin Aldabe
Physics , 1996, DOI: 10.1016/S0370-2693(96)01235-X
Abstract: In systems with constraints, physical states must be annihilated by the constraints. We make use of this rule to construct physical asymptotic states in the Skyrme model. The standard derivation of the Born terms with asymptotic physical states shows that there is no Yukawa coupling for the Skyrmion. We propose a remedy tested in other solitonic models: A Wilsonian action obtained after integrating the energetic mesons and where the Skyrmion is a quantum state should have a Yukawa coupling.
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