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Search Results: 1 - 10 of 191646 matches for " Estrada G. "
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The logic of the violence in the civil war: The armed conflict in Colombia
Estrada G.,Fernando;
Perfil de Coyuntura Económica , 2011,
Abstract: this article proposes a reading of the armed conflict from an evolutionary design that takes into account the concept of private protection agencies in the works of schelling / nozick / gambetta. their aim is to assess the dynamics of conflict and changes from its author's scientific output. a context of conflicts that includes new expressions of violence and the relative failure of the paramilitary reintegration involves using new analytical models (argumentation, game theory and inconsistent information). the recent evolution of emerging gangs and their expansion into areas that were paramilitary camps requires monitoring not only of the government and the authorities, but those investigating the conflict in the present tense. the author provides heuristic research support from schelling's theory of strategy, nozick's agencies and the protection, and gambetta's recent contributions to the relationship between organized crime and drug cartels.
The logic of the violence in the civil war: The armed conflict in Colombia
Fernando Estrada G.
Perfil de Coyuntura Económica , 2011,
Abstract: Este artículo propone una lectura del conflicto armado a partir de un dise o evolutivo que tenga en cuenta el concepto de agencias de protección privada en las obras de Schelling / Nozick / Gambetta. Su objetivo es evaluar la dinámica del conflicto y los cambios de la producción científica de los autores. El contexto de los conflictos, que incluye, nuevas expresiones de la violencia y el relativo fracaso de la reinserción paramilitar implica usar nuevosmodelos de análisis (la argumentación, la teoría de juegos y la información inconsistente). La evolución reciente de las bandas emergentes y su expansión a zonas que eran campamentos paramilitares requiere el seguimiento no sólo del gobierno y las autoridades, sino la investigación del conflicto en la actualidad. El autor ofrece soporte a la investigación heurística de la teoría estratégica de Schelling, las agencias y la protección de Nozick y las recientes contribuciones de Gambetta a la relación entre el crimen organizado y los carteles de la droga.
Magnification Bias in Gravitational Arc Statistics
G. B. Caminha,J. Estrada,M. Makler
Physics , 2013,
Abstract: The statistics of gravitational arcs in galaxy clusters is a powerful probe of cluster structure and may provide complementary cosmological constraints. Despite recent progresses, discrepancies still remain among modelling and observations of arc abundance, specially regarding the redshift distribution of strong lensing clusters. Besides, fast "semi-analytic" methods still have to incorporate the success obtained with simulations. In this paper we discuss the contribution of the magnification in gravitational arc statistics. Although lensing conserves surface brightness, the magnification increases the signal-to-noise ratio of the arcs, enhancing their detectability. We present an approach to include this and other observational effects in semi-analytic calculations for arc statistics. The cross section for arc formation ({\sigma}) is computed through a semi-analytic method based on the ratio of the eigenvalues of the magnification tensor. Using this approach we obtained the scaling of {\sigma} with respect to the magnification, and other parameters, allowing for a fast computation of the cross section. We apply this method to evaluate the expected number of arcs per cluster using an elliptical Navarro--Frenk--White matter distribution. Our results show that the magnification has a strong effect on the arc abundance, enhancing the fraction of arcs, moving the peak of the arc fraction to higher redshifts, and softening its decrease at high redshifts. We argue that the effect of magnification should be included in arc statistics modelling and that it could help to reconcile arcs statistics predictions with the observational data.
Estrada A,Germán Darío; Soto G,Alberto;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2011,
Abstract: compsus sp. is an important pest associated to citrus cultivation because of the damage it causes to plants. the aim of this study was to evaluate parasitism exerted by fidiobia sp. on compsus sp. positions on field conditions and determine the population fluctuation of the pest
Nuevo Sistema Satelital de Monitoreo Oceánico para México
Cerdeira-Estrada, S;López-Salda?a, G;
Ciencias marinas , 2011,
Abstract: to analyze patterns in marine productivity, harmful algal blooms, thermal stress in coral reefs, and oceanographic processes, optical and biophysical marine parameters, such as sea surface temperature, and ocean color products, such as chlorophyll-a concentration, diffuse attenuation coefficient, total suspended matter concentration, chlorophyll fluorescence line height, and remote sensing reflectance, are required. in this paper we present a novel automatic satellite-based ocean monitoring system (satmo) developed to provide, in near real-time, continuous spatial data sets of the above-mentioned variables for marine-coastal ecosystems in the gulf of mexico, northeastern pacific ocean, and western caribbean sea, with 1 km spatial resolution. the products are obtained from moderate resolution imaging spectroradiometer (modis) images received at the direct readout ground station (located at conabio) after each overpass of the aqua and terra satellites. in addition, at the end of each week and month the system provides composite images for several ocean products, as well as weekly and monthly anomaly composites for chlorophyll-a concentration and sea surface temperature. these anomaly data are reported for the first time for the study region and represent valuable information for analyzing time series of ocean color data for the study of coastal and marine ecosystems in mexico, central america, and the western caribbean.
Racionalidad de los esquemas de superovulación y sincronización en la transferencia de embriones en bovinos: ¿terapéutica basada en la evidencia o ausencia de ética?
Maldonado Estrada,Juan G; Bolívar,Paula A;
Revista Colombiana de Ciencias Pecuarias , 2008,
Abstract: since the beginning of the use of bovine embryo transfer (et) in colombia, hormonal protocols for superovulation (sov) of donors and for synchronization of recipients (rs) have been used in accordance with protocols reported elsewhere. several variations of et protocols have been reported most of they not based in controlled clinical studies but in the supposed pharmacological mechanisms of action of the used hormones, neither with pharmacokinetic studies nor considering the potential collateral effects on cow's fertility. such collateral effects could be directly or indirectly related with the uncontrolled use of exogenous hormones, or with the time-related additional open days of donor and recipients, without considering the bioethics for animal experimentation. the huge proliferation of protocols for sov and rs aims for improving both grade i and ii (transferable or freezable embryos) embryo yield per transfer, and pregnancy rates for transferred embryos, without having achieved significant improvements during the last 20 years all around the world. in the present review we critic the use of exogenous hormones in bovine et with emphasis in the rationality of indiscriminating use of exogenous hormones and embryo yield. finally, we suggest several arguments on the bioethics of the protocols for sov and rs in bovine et.
Análisis de costos de esquemas de transferencia de embriones bovinos utilizados en Colombia
Bolívar,Paula A; Maldonado Estrada,Juan G;
Revista Colombiana de Ciencias Pecuarias , 2008,
Abstract: in this work an estimated calculation of the cost of three of the most common protocols for superovulation and embryo trasnsfer in colombia is presented. estimate costs were defined according to commercial avalilable products at december 2005, taking into account the following sources of costs: 1) superovulation of donor cows, 2) sinchronization of receptor cows, and 3) personnel. hormonal schedules that were analyzed included: schedule 1 (s1), sinchronization with progesterone implants, fsh (continuous dose) gnrh (synchronization of ovulation), and ai; schedule 2 (s2), sinchronization with two dose prostaglandins, fsh (continuous dose), lh source and insemination; and schedule 3 (s3), sinchronization with progesterone implants, fsh (continuous dose), prostaglandin, gnrh (36h) after, and ai. costs were calculated on the basis of 6.3, 6.6, and 10.3 transferable embryos/flush, for schedule 1, 2 and 3, respectively; flushes/donor/year (n = 4), and global pregnancy rate (50 or 100%). the estimated costs for transferable embryo were us 239.8 ($ 479.585.7), us 156 ($ 312.879.0), y us 115.1 ($ 230.186.5) for s1, s2, and s3, respectively. no statistically significant differences (p>0.05) between schedules were found for cost components. average costs/transferable embryo were increased to us 359.7 ($719.378.6), us 234.7 ($ 469.318.4), y us 172.6 ($ 345.279.7), respectively, when 50% of transferred embryo losses were included in the analysis. to our knowledge, this is the first report on estimated costs for embryo transfer in colombia. in this work several cost components for calculating the cost of et according to each hormonal schedule are provided.
Interacción de los factores ambientales con la respuesta del comportamiento productivo en pollos de engorde
Estrada P,Mónica M; Márquez G,Sara M;
Revista Colombiana de Ciencias Pecuarias , 2005,
Abstract: the modern poultry keeping, as any other industry, has the profitability as a north, and in a market so competed as the one that has imposed the economy globalization, the producers don?t have different option than looking for the maximum of efficiency; therefore, in order to chickens express the maximum productive potential of its genetic, it is indispensable to manage an appropriate environment that provides them the appropriate environmental conditions. the temperature, humidity, quality of the air, these are some of the environmental factors to keep in mind during the productive period of the domestic birds.
Three-dimensional numerical simulation of the natural convection in an open tilted cubic cavity
Hinojosa, J.F.;Alvarez, G.;Estrada, C.A.;
Revista mexicana de física , 2006,
Abstract: in this work the numerical results of the heat transfer by natural convection in a tilted open cubic cavity are presented. the most important assumptions in the mathematical formulation are two: the flow is laminar, and the boussinesq approximation is valid. the conservation equations in primitive variables are solved using the finite volume method and the simplec algorithm. the advective terms are approximated by the smart scheme, and the diffusive terms are approximated using the central differencing scheme. the results in the steady state are obtained for a rayleigh range from 104 to 107 and for a range of 0-180° for the inclination angles of the cavity. the results show that for high rayleigh numbers, the nusselt number changes substantially with the inclination angle of the cavity. the numerical model predicted nusselt number oscillations for low angles and high rayleigh numbers.
Lactation performance of Holstein and Holstein x Gyr cattle under intensive condition in a subtropical environment
Mellado, Miguel;Coronel, Francisco;Estrada, Alfredo;Ríos, Francisco G.;
Tropical and subtropical agroecosystems , 2011,
Abstract: data from 289 milk yield records of purebred holstein (h), ? holstein ? gyr (?h ?g) and ? holstein ? gyr (?h ?g) were used to compare milk production traits of these genotypes in an intensive operation in a subtropical region of northwestern mexico. the performance traits studied were: 305-d milk yield days (p305), total milk yield per lactation (tmy), average daily milk production (dmp); lactation length (ll), peak milk yield (pm) and day of peak milk. higher (p<0.05) p305 averages were observed for purebred holsteins (5417 ± 96 kg) than ?h ?g (4807 ± 131kg) and ?h ?g (4541 ± 92 kg). the shortest lactations were observed for ?h ?g animals (288 ± 2.0 d) whereas the longest lactations were observed for purebred holstein (303 ± 2.id). the highest 305-d milk yield was observed in cows calving in january (5283 ± 1090 kg), whereas the lowest milk yield occurred with calvings in june (3989 ± 896 kg). these results indicate that, under intensive management in a subtropical setting, purebred holstein performed better than crossbred animals, in terms of milk yield. however, in this subtropical environment reproductive performance of purebred holstein cows is very poor; thus, this study emphasizes the importance of crossbreeding holstein x gyr cattle to produce cows that are more adapted to the hot-humid environmental conditions of the region. these results also showed the drastic impact of heat stress during the summer months on the milk yield of these cows.
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