213 research outputs found

    Tendencies in Mexican-Russian economical relationship

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    In this article the questions of transformation and strengthening of the Russian-Mexican cooperation at the present stage are considered. The main products for importation and exportation of Russia and Mexico are listed for the branches of industry, agriculture, science and education. The article describes the relationship between Russia and Mexico in tourism and how it can help to improve their economic growth and country development in the next periods. The directions of development of relations in the sphere of tourism are named

    Bayesian Analysis of the (Generalized) Chaplygin Gas and Cosmological Constant Models using the 157 gold SNe Ia Data

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    The generalized Chaplygin gas model (GCGM) contains 5 free parameters, here, they are constrained through the type Ia supernovae data, i.e., the ``gold sample'' of 157 supernovae data. Negative and large positive values for α\alpha are taken into account. The analysis is made by employing the Bayesian statistics and the prediction for each parameter is obtained by marginalizing on the remained ones. This procedure leads to the following predictions: α=0.750.24+4.04\alpha = - 0.75^{+4.04}_{-0.24}, H0=65.001.75+1.77H_0=65.00^{+1.77}_{-1.75}, Ωk0=0.775.94+1.14\Omega_{k0} = - 0.77^{+1.14}_{-5.94}, Ωm0=0.000.00+1.95\Omega_{m0} = 0.00^{+1.95}_{-0.00}, Ωc0=1.360.85+5.36\Omega_{c0} = 1.36^{+5.36}_{-0.85}, Aˉ=1.0000.534+0.000\bar A = 1.000^{+0.000}_{-0.534}. Through the same analysis the specific case of the ordinary Chaplygin gas model (CGM), for which α=1\alpha = 1, is studied. In this case, there are now four free parameters and the predictions for them are: H0=65.011.71+1.81H_0 = 65.01^{+1.81}_{-1.71}, Ωk0=2.730.97+1.53\Omega_{k0} = - 2.73^{+1.53}_{-0.97}, Ωm0=0.000.00+1.22\Omega_{m0} = 0.00^{+1.22}_{-0.00}, Ωc0=1.340.70+0.94\Omega_{c0} = 1.34^{+0.94}_{-0.70}, Aˉ=1.0000.270+0.000\bar A = 1.000^{+0.000}_{-0.270}. To complete the analysis the Λ\LambdaCDM, with its three free parameters, is considered. For all these models, particular cases are considered where one or two parameters are fixed. The age of the Universe, the deceleration parameter and the moment the Universe begins to accelerate are also evaluated. The quartessence scenario, is favoured. A closed (and in some cases a flat) and accelerating Universe is also preferred. The CGM case α=1\alpha = 1 is far from been ruled out, and it is even preferred in some particular cases. In most of the cases the Λ\LambdaCDM is disfavoured with respect to GCGM and CGM.Comment: 23 pages, LaTeX 2e, 6 tables, 38 EPS figures, uses graphic

    Likelihood Analysis of Repeating in the BATSE Catalogue

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    I describe a new likelihood technique, based on counts-in-cells statistics, that I use to analyze repeating in the BATSE 1B and 2B catalogues. Using the 1B data, I find that repeating is preferred over non-repeating by 4.3:1 odds, with a well-defined peak at 5-6 repetitions per source. I find that the post-1B data are consistent with the repeating model inferred from the 1B data, after taking into account the lower fraction of bursts with well-determined positions. Combining the two data sets, I find that the odds favoring repeating over non-repeating are almost unaffected at 4:1, with a narrower peak at 5 repetitions per source. I conclude that the data sets are consistent both with each other and with repeating, and that for these data sets the odds favor repeating.Comment: 5 pages including 3 encapsulated figures, as a uuencoded, gzipped, Postscript file. To appear in Proc. of the 1995 La Jolla workshop ``High Velocity Neutron Stars and Gamma-Ray Bursts'' eds. Rothschild, R. et al., AIP, New Yor

    Sex differences in comorbidity between substance use and mental health in adolescents: Two sides of the same coin

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    Background: This study aims to evaluate sex differences in alcohol and cannabis use and mental health disorders (MHD) in adolescents, and to evaluate the predictive role of mental health disorders for alcohol and cannabis use disorders (AUD and CUD respectively). Method: A sample of 863 adolescents from the general population (53.7% girls, Mage = 16.62, SD = 0.85) completed a computerized battery including questions on substance use frequency, the Brief Symptom Inventory, the Cannabis Problems Questionnaire for Adolescents - Short version, the Rutgers Alcohol Problem Index and the DSM-IV-TR criteria for AUD and CUD. Bivariate analyses and binary logistic regressions were performed. Results: Girls presented significantly more mental health problems and a higher prevalence of comorbidity between SUD and MHD. Obsessivecompulsive symptoms and phobic anxiety indicated a higher risk of AUD, whereas depression and interaction between hostility and obsessivecompulsive disorder indicated a higher risk of CUD. Conclusions: Comorbidity between SUD and MHD is high among adolescents, and significantly higher among girls. Antecedentes: el objetivo de esta investigación es evaluar las diferencias de sexo en el uso de cannabis y alcohol y en trastornos de salud mental TSM en adolescentes, y el rol predictivo de los TSM sobre los trastornos por uso de alcohol y cannabis (TUA y TUC, respectivamente). Método: una muestra de 863 adolescentes de la población general (53, 7% chicas, edad media = 16.62, DT = 0, 85) completaron una batería informatizada sobre la frecuencia de uso de sustancias, el Inventario Breve de Síntomas, el Cuestionario de Problemas por Consumo de Cannabis - versión breve, el Índice de Rutgers de Problemas con el Alcohol y los criterios DSM-IV-TR para el TUA y TUC. Se realizaron análisis bivariados y de regresión logística binaria. Resultados: las chicas presentaron significativamente más problemas de salud mental y mayor prevalencia de comorbilidad entre TUS y TSM. El trastorno obsesivo-compulsivo (TOC) y la ansiedad fóbica indicaron un mayor riesgo de TUA, mientras que la depresión y la interacción entre hostilidad y TOC indicaron mayor riesgo de TUC. Conclusiones: la comorbilidad entre TUS y TSM es alta entre los adolescentes, y significativamente mayor entre las chicas

    Síntesis de derivados de 2-anilino-3-cloro- 1,4-naftoquinona promovida por microondas y ultrasonido

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    En este trabajo se usaron las técnicas de microondas(MO) y ultrasonido (US) como métodos alternativos de activación, para la obtención de derivados de 2-anilino-3-cloronaftoquinona (ACNQ); con diferentes anilinasy sustituyentes electroatractores (4-F, 4-Cl, 4-Br,4-I y 4-NO2) y electrodonadores (2-OCH3, 4-OCH3y 4-OCH2CH3). Sintetizar este tipo de moléculas es de gran importancia debido a que están presentes en compuestos biológicamente activos. Los rendimientos hacia el producto de interés fueron altos en la mayoría de los casos, además los tiempos de reacción disminuyeron sustancialmente respecto a la síntesis hecha por calentamiento convencional (SCC). Todos los compuestosse caracterizaron por espectroscopia ultravioleta visible (UV-Vis), de infrarrojo (IR), de resonancia magnética nuclear (RMN) y por espectrometría de masas (EM)

    Polarization Modulation Instability in Dispersion-Engineered Photonic Crystal Fibers

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    Generation of widely spaced polarization modulation instability (PMI) sidebands in a wide collection of photonic crystal fibers (PCF), including liquid-filled PCFs, is reported. The contribution of chromatic dispersion and birefringence to the net linear phase mismatch of PMI is investigated in all-normal dispersion PCFs and in PCFs with one (or two) zero dispersion wavelengths. Large frequency shift sidebands are demonstrated experimentally. Suitable fabrication parameters for air-filled and liquid-filled PCFs are proposed as guidelines for the development of dual-wavelength light sources based on PMI

    Validity evidence of the multidimensional emotional disorders inventory among non-clinical spanish university students

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    The current diagnostic systems for mental health disorders are categorical, which, it has been argued, poorly reflect the reality of mental health problems. This is especially relevant in emotional disorders (EDs), especially due to the existing comorbidity between supposedly different disorders. To address this, Brown and Barlow developed a hybrid dimensional−categorical approach to EDs that can be evaluated with the Multidimensional Emotional Disorder Inventory (MEDI), a transdiagnostic self-report questionnaire. This study aims to adapt and explore the sources of validity evidence of the MEDI in a non-clinical sample of Spanish university students (n = 455). Two confirmatory analyses were performed: one with a four-dimensional structure obtained with an exploratory analysis and another with the original nine-dimensional structure of the MEDI. The latter obtained a better fit. The descriptive data, including percentiles, T-scores, and sex differences in total scores are also provided, together with sources of validity evidence. These revealed significant moderate interrelations between factors and with related measures (e.g., personality, depression, and anxiety). This study adapted the MEDI for use in Spanish, provides further support about its factor structure, and offers novel data about its validity sources. The MEDI makes the evaluation of dimensional and transdiagnostic models easier, which might be fundamental in present and future research and clinical practice

    Concurrent validity of the Alcohol Purchase Task for measuring the reinforcing efficacy of alcohol: an updated systematic review and meta-analysis

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    Background and aims: An early meta-analysis testing the concurrent validity of the Alcohol Purchase Task (APT), a measure of alcohol''s relative reinforcing value, reported mixed associations, but predated a large number of studies. This systematic review and meta-analysis sought to: (1) estimate the relationships between trait-based alcohol demand indices from the APT and multiple alcohol indicators, (2) test several moderators and (3) analyze small study effects. Methods: A meta-analysis of 50 cross-sectional studies in four databases (n = 18 466, females = 43.32%). Sex, year of publication, number of APT prices and index transformations (logarithmic, square root or none) were considered as moderators. Small study effects were examined by using the Begg–Mazumdar, Egger''s and Duval & Tweedie''s trim-and-fill tests. Alcohol indicators were quantity of alcohol use, number of heavy drinking episodes, alcohol-related problems and hazardous drinking. APT indices were intensity (i.e. consumption at zero cost), elasticity (i.e. sensitivity to increases in costs), Omax (i.e. maximum expenditure), Pmax (i.e. price associated to Omax) and breakpoint (i.e. price at which consumption ceases). Results: All alcohol demand indices were significantly associated with all alcohol-related outcomes (r = 0.132–0.494), except Pmax, which was significantly associated with alcohol-related problems only (r = 0.064). The greatest associations were evinced between intensity in relation to alcohol use, hazardous drinking and heavy drinking and between Omax and alcohol use. All the tested moderators emerged as significant moderators. Evidence of small-study effects was limited. Conclusions: The Alcohol Purchase Task appears to have concurrent validity in alcohol research. Intensity and Omax are the most relevant indices to account for alcohol involvement

    Inferring the Spatial and Energy Distribution of Gamma Ray Burst Sources. III. Anisotropic Models

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    We use Bayesian methods to study anisotropic models for the distribution of gamma ray burst intensities and directions reported in the Third BATSE Catalog (3B catalog) of gamma ray bursts. We analyze data obtained using both the 64 ms and 1024 ms measuring timescales. We study both purely local models in which burst sources (``bursters'') are presumed to be distributed in extended halos about the Galaxy and M31, and mixed models consisting of a cosmological population of standard candle bursters and a local population distributed throughout a standard Bahcall-Soneira dark matter halo with a 2 kpc core. We find that the purely local models we have studied can account for the 3B data as successfully as cosmological models, provided one considers halos with core sizes significantly larger than those used to model the distribution of dark matter. We infer core sizes for the halo distribution that are smaller than one might expect based on popular semiquantitative arguments, and show why such arguments can lead to unwarranted conclusions. We also find that the 3B data do not constrain the width of power-law luminosity functions for burst sources. Our analysis of mixed models finds two families of models that can successfully account for the data: models with up to 20% of observed bursts in a bright local population visible to ~ 50 kpc; and models with up to 50% of observed bursts in a dim local population visible only nearby (to less than a disk scale height). These models fit as well or better than purely cosmological models. They indicate that a surprisingly large local, anisotropic component could be present whose size is comparable to the sizes of hypothetical classes of bursts inferred from analyses of temporal and spectral characteristics.Comment: 35 pages, 18 figures; submitted to The Astrophysical Journal, 12/9

    Bayesian model comparison applied to the Explorer-Nautilus 2001 coincidence data

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    Bayesian reasoning is applied to the data by the ROG Collaboration, in which gravitational wave (g.w.) signals are searched for in a coincidence experiment between Explorer and Nautilus. The use of Bayesian reasoning allows, under well defined hypotheses, even tiny pieces of evidence in favor of each model to be extracted from the data. The combination of the data of several experiments can therefore be performed in an optimal and efficient way. Some models for Galactic sources are considered and, within each model, the experimental result is summarized with the likelihood rescaled to the insensitivity limit value (``R{\cal R} function''). The model comparison result is given in in terms of Bayes factors, which quantify how the ratio of beliefs about two alternative models are modified by the experimental observationComment: 16 pages, 4 figures. Presented at the GWDAW2002 conference, held in Kyoto on Dec.,2002. This version includes comments by the referees of CQG, which has accepted the paper for pubblication in the special issue of the conference. In particular, note that in Eq. 12 there was a typeset error. As suggested by one of the referees, a uniform prior in Log(alpha) has also been considere
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