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Search Results: 1 - 10 of 458000 matches for " L. F. G. Gonzalez "
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Childhood Obesity in the Region of Valencia, Spain: Evolution and Prevention Strategies
A. Morales,L. Jodar,G. Gonzalez,F.J. Santonja
Journal of Medical Sciences , 2008,
Abstract: In this study there are two main aims. The first one is to model and predict the incidence of obesity in the 3-5 years old population in the coming years in the region of Valencia, Spain. The second aim of this research is to use the constructed model to analyze the possible strategies in order to prevent the spread of obesity. At first a logistic regression statistical analysis of sociocultural variables of children with weight problems is performed. The result of this logistic regression statistical analysis suggests that sociocultural factors in the region of Valencia where the child grows up influence the development of overweight or obesity. Thus, this result permit to consider the hypothesis that the obesity is a health concern that depends on sociocultural factors and it is transmitted by the spread of unhealthy eating habits. In this way the hypothesis permits to construct a mathematical epidemiological type model in order to forecast obesity prevalence and to understand the mechanisms of the obesity spread. Using the constructed epidemiological mathematical model it is predicted that in the coming years, an increasing trend in the overweight and obese 3-5 years old children in the region of Valencia is predicted if the actual parameters of the mathematical model stay invariant. In addition, the different numerical simulations performed with the constructed epidemiological mathematical model indicate that the most likely successful strategy to tackle the obesity is through educational campaigns about the risk of unhealthy eating habits. This study shows how an epidemiological type mathematical model is an interesting tool to study the obesity transmissions dynamics in the population. It is useful to predict the prevalence of the obesity and study strategies to tackle it.
A bright radio HH object with large proper motions in the massive star-forming region W75N
C. Carrasco-Gonzalez,L. F. Rodriguez,J. M. Torrelles,G. Anglada,O. Gonzalez-Martin
Physics , 2010, DOI: 10.1088/0004-6256/139/6/2433
Abstract: We analyze radio continuum and line observations from the archives of the Very Large Array, as well as X-ray observations from the \emph{Chandra} archive of the region of massive star formation W75N. Five radio continuum sources are detected: VLA 1, VLA 2, VLA 3, Bc, and VLA 4. VLA 3 appears to be a radio jet; we detect J=1-0, v=0 SiO emission towards it, probably tracing the inner parts of a molecular outflow. The radio continuum source Bc, previously believed to be tracing an independent star, is found to exhibit important changes in total flux density, morphology, and position. These results suggest that source Bc is actually a radio Herbig-Haro object, one of the brightest known, powered by the VLA~3 jet source. VLA 4 is a new radio continuum component, located a few arcsec to the south of the group of previously known radio sources. Strong and broad (1,1) and (2,2) ammonia emission is detected from the region containing the radio sources VLA~1, VLA~2, and VLA~3. Finally, the 2-10 keV emission seen in the \emph{Chandra}/ACIS image shows two regions that could be the termination shocks of the outflows from the multiple sources observed in W75N.
Corrosion Inhibition of Carbon Steel in Acidic Mediaby Using Actinidia deliciosa (Kiwifruit) Extract  [PDF]
M. I. Arias-Montoya, G. F. Dominguez-Pati?o, J. G. Gonzalez-Rodriguez, J. A. Dominguez-Pati?o, M. L. Dominguez-Pati?o
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.511045
Abstract: The corrosion inhibition of 1018 carbon steel in 0.5 M H2SO4 by using Actinidia deliciosa (Kiwifruit) peel extract has been investigated by using potentiodynamic polarization curves and electro-chemical impedance spectroscopy. Two kinds of extracts are investigated, one from the tender, and another one from ripe Actinidia deliciosa. Concentrations include 0, 25, 50, 75, and 100 ppm at room temperature. Results indicate that both kind of extracts acted as good corrosion inhibitors, is more efficient in the ripe extract. Corrosion inhibition efficiency increases with increasing its concentration for ripe extract, whereas for the tender Actinidia deliciosa, the higest inhibitor efficiency is obtained by adding 25 ppm and decresaing with a further increase in its concentration. Both extracts improve the passive film properties by decreasing the passive current density values. It is found that the corrosion inhibition is due to the presence of heteroatoms present in Actinidia deliciosa, mainly quercitine, which is physically adsorbed in the steel following a Frumkin type of adsorption isotherm which forms a protective film.
A Study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as Green Corrosion Inhibitors for Carbon Steel in Sulfuric Acid  [PDF]
M. J. Garcia-Ramirez, G. F. Dominguez Pati?o, J. G. Gonzalez-Rodriguez, M. L. Dominguez-Pati?o, J. A. Dominguez-Pati?o
Advances in Materials Physics and Chemistry (AMPC) , 2016, DOI: 10.4236/ampc.2016.62002
Abstract: A study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as eco-friendly corrosion inhibitors for 1018 carbon steel in 0.5 M H2SO4 has been carried out by using weight loss tests, potentiodynamic polarization curves and electrochemical impedance spectroscopy measuremnts. Results have shown that the three extracts performed as good corrosion inhibitors, but the Eruca vesicaria exhibited the best performance followed by Erythrina americana. The three inhibitors formed a protective, passive film which protected the steel from corrosion. This was because they contain antioxidants present in their molecular structure with heteroatoms such as N, C and O like phenols, amino acids, etc., which react with metal and environment to form the protective film.
On the origin of the gamma-ray emission from the flaring blazar PKS 1222+216
F. Tavecchio,J. Becerra-Gonzalez,G. Ghisellini,A. Stamerra,G. Bonnoli,L. Foschini,L. Maraschi
Physics , 2011, DOI: 10.1051/0004-6361/201117204
Abstract: The flat spectrum radio quasar PKS 1222+216 was detected in the very high energy gamma-ray band by MAGIC during a highly active gamma-ray phase following an alert by the LAT onboard Fermi. Its relatively hard spectrum without a cut off, together with the observed variability on timescale of ~10 min challenges standard emission models. If the emission originates in a portion of the relativistic jet located inside the BLR, severe absorption of gamma rays above few tens of GeV is expected due to the pair production process. These observations imply the existence of a very compact (R_b ~5 x 10^{14} cm) and very fast blob located far beyond the BLR radius, responsible for the rapidly varying high energy flux. However the long term (days-weeks) coherent evolution of the GeV flux recorded by LAT indicates that there could be also the substantial contribution from another larger emission region. We model the spectral energy distribution of PKS 1222+216 during the epoch of the MAGIC detection assuming three different scenarios,: (1) a one-zone model considering only the emission from a compact blob outside the BLR; (2) a two-zone model considering the compact blob plus an emitting region filling the whole jet cross-section located outside the BLR and (3) a two zone model with the jet emitting region inside the BLR. We find that in all cases the high-energy emission from the compact blob is dominated by the inverse Compton scattering of the IR thermal radiation of the dusty torus. Both regions are matter dominated, with a negligible Poynting flux. These results disfavor models in which the compact blob is the result of reconnection events inside the jet or "needles" of high-energy electrons. Instead, the observational framework and our radiative models could be compatible with scenarios in which the jet is re-collimated and focussed at large distances from the central BH.
STUDY OF THE Fe-75%Ag SYSTEM OBTAINED BY MECHANICAL ALLOYING
Bonyuet,D; González,G; Ochoa,J; Gonzalez-Jimenez,F; D′Onofrio,L;
Revista Latinoamericana de Metalurgia y Materiales , 2002,
Abstract: mechanical alloying (ma) is a powder processing technique, which allows us to induce solid state reactions in binary systems immiscible in equilibrium. fe and ag have a mutually repulsive nature that makes them completely immiscible under thermodynamically stable conditions. the ball milling process being a non-equilibrium technique seems promising in obtaining at least a partial solid solution in this system. mixtures of fe and ag powders with 75 wt% ag were studied by x-ray diffraction (xrd), scanning electron microscopy (sem) and transmission electron microscopy (tem). we have found that it is possible to obtain a small mutual solid solution in this system by ma. this is also confirmed by m?ssbauer spectroscopy.
Active-active and active-sterile neutrino oscillation solutions to the atmospheric neutrino anomaly
M. C. Gonzalez-Garcia,H. Nunokawa,O. L. G. Peres,J. W. F. Valle
Physics , 1998, DOI: 10.1016/S0550-3213(98)00834-7
Abstract: We perform a fit to the full data set corresponding to 33.3 kt-yr of data of the Super-Kamiokande experiment as well as to all other experiments in order to compare the two most likely solutions to the atmospheric neutrino anomaly in terms of oscillations in the $\nu_\mu \to \nu_\tau$ and $\nu_\mu \to \nu_s$ channels. Using state-of-the-art atmospheric neutrino fluxes we have determined the allowed regions of oscillation parameters for both channels. We find that the $\Delta m^2$ values for the active-sterile oscillations (both for positive and negative $\Delta m^2$) are higher than for the $\nu_\mu \to \nu_\tau$ case, and that the increased Super-Kamiokande sample slightly favours $\nu_\mu \to \nu_\tau$ oscillations over oscillations into a sterile species $\nu_s$, $\nu_\mu \to \nu_s$, and disfavours $\nu_\mu \to \nu_e$. We also give the zenith angle distributions predicted for the best fit points in each of the possible oscillation channels. Finally we compare our determinations of the atmospheric neutrino oscillation parameters with the expected sensitivities of future long-baseline experiments K2K, MINOS, ICARUS, OPERA and NOE.
The Peculiar Radio Source M17 JVLA 35
L. F. Rodriguez,C. Carrasco-Gonzalez,G. Montes,M. Tapia
Physics , 2014, DOI: 10.1088/0004-6256/148/1/20
Abstract: M17 JVLA 35 is a radio source detected in projection against the M17 HII region. In recent observations, its spectrum between 4.96 and 8.46 GHz was found to be positive and very steep, with $\alpha \geq 2.9 \pm 0.6$ ($S_\nu \propto \nu^\alpha$). Here we present Very Large Array observations made in the 18.5 to 36.5 GHz region that indicate a spectral turnover at $\sim$13 GHz and a negative spectral index ($\alpha \simeq -2.0$) at higher frequencies. The spectrum is consistent with that of an extragalactic High Frequency Peaker (HFP). However, M17 JVLA 35 has an angular size of $\sim0\rlap.{''}5$ at 8.46 GHz, while HFPs have extremely compact, milliarcsecond dimensions. We discuss other possible models for the spectrum of the source and do not find them feasible. Finally, we propose that M17 JVLA35 is indeed an HFP but that its angular size becomes broadened by plasma scattering as its radiation travels across M17. If our interpretation is correct, accurate measurements of the angular size of M17 JVLA35 across the centimeter range should reveal the expected $\nu^{-2}$ dependence.
Bipolariton laser emission from a GaAs microcavity
L. M. Moreira,J. C. Gonzalez,A. G. Oliveira,F. M. Matinaga
Physics , 2005,
Abstract: Biexciton emission properties were studied in a single GaAs quantum well semiconductor planar microcavity by photoluminescence measurements at low temperatures. At high pump intensity a bipolariton emission appears close to the lower polariton mode. This new mode appears when we detune the cavity resonance out of the lower polariton branch, showing a laser like behavior. Very small lines widths were measured, lying below 110 μeV and 150 μeV for polariton and bipolariton emission respectively. The input/output power (I/O) measurements show that the bipolariton emission has a weaker coupling efficiency compared to previous results for polariton emission. Simultaneous photoluminescence and near field measurements show that the polariton and bipolariton emission are spectrally and spatially separated.
Non-detection of magnetic fields in the central stars of the planetary nebulae NGC 1360 and LSS 1362
F. Leone,M. J. Martinez Gonzalez,R. L. M. Corradi,G. Privitera,R. Manso Sainz
Physics , 2011, DOI: 10.1088/2041-8205/731/2/L33
Abstract: The presence of magnetic fields is an attractive hypothesis for shaping PNe. We report on observations of the central star of the two Planetary Nebulae NGC1360 and LSS1326. We performed spectroscopy on circularly polarized light with the FOcal Reducer and low dispersion Spectrograph at the Very Large Telescope of the European Southern Observatory. Contrary to previous reports (Jordan et al. 2005, A&A, 432, 273), we find that the effective magnetic field, that is the average over the visible stellar disk of longitudinal components of the magnetic fields, is null within errors for both stars. We conclude that a direct evidence of magnetic fields on the central stars of PNe is still missing --- either the magnetic field is much weaker (< 600 G) than previously reported, or more complex (thus leading to cancellations), or both. Certainly, indirect evidences (e.g., MASER emission) fully justify further efforts to study the strength and morphology of such magnetic fields.
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