2,879 research outputs found
B->pi,K,eta Decay Formfactors from Light-Cone Sum Rules
We present an improved calculation of all B -> light pseudoscalar formfactors
from light-cone sum rules, including one-loop radiative corrections to twist-2
and twist-3 contributions, and leading order twist-4 corrections. The total
theoretical uncertainty of our results at zero momentum transfer is 10 to 13%.
The dependence of the formfactors on the momentum transfer q^2 is parametrized
in a simple way that is consistent with their analytical properties and is
valid for all physical q^2. The uncertainty of the extrapolation in q^2 on the
semileptonic decay rate Gamma(B -> pi e nu) is estimated to be 5%.Comment: 10 pages; talk given at Continuous Advances in QCD 2004, Minneapolis,
May 200
B -> K* gamma vs B -> rho gamma and |V_td/V_ts|
We determine |V_{\rm td}/V_{\rm ts}| = 0.192 \pm 0.016_ exp \pm 0.014_th from
B -> (K^*,rho) gamma as measured by the B-factories Babar and Belle.
This version differs from the original proceedings by the inclusion of the
new BaBar measurement of B -> rho(omega) gamma presented at ICHEP 2006, which
significantly shifts the results for |V_{td}/V_{ts}|.Comment: Proceedings for QAQCD 06, Minneapolis Including new BaBar measurement
B->rho gamma presented at ICHEP 2006, which significantly shifts the result
of |V_td/V_ts
|V_td/V_ts| from B-> V gamma
The dominant theoretical uncertainty in extracting |V_td/V_ts| from the ratio
of branching ratios R=B(B->(rho,omega)gamma)/B(B->K* gamma) is given by the
ratio of form factors xi=T_1^{B->K*}(0)/T_1^{B->rho}(0). We re-examine xi in
the framework of QCD sum rules on the light-cone, taking into account hitherto
neglected SU(3)-breaking effects. We find xi=1.17 \pm 0.09. Using QCD
factorisation for the branching ratios, and the current experimental average
for R quoted by HFAG, this translates into |V_td/V_ts|^HFAG_{B->V gamma} =
0.192 \pm 0.014(th) \pm 0.016(exp). This result agrees, within errors, with
that obtained from the Standard Model unitarity triangle, |V_td/V_ts|_SM =
0.216 \pm 0.029, based on tree-level-only processes, and with
|V_td/V_ts|_{Delta m} = 0.2060^{+0.0081}_{-0.0060}(th) \pm 0.0007(exp), from
the CDF measurement of B_s oscillations.Comment: 23 pages; new BaBar results on B->(rho/omega)gamma include
Un ejercicio de tipificación de la relación trabajo y familia
La investigación desarrollada tiene tres puntos de partida. Uno relacionado con el funcionamiento y las formas de organización que adquieren las unidades económicas denominadas micronegocios; otro vinculado con la estructura y dinámica familiar y finalmente, un tercero que busca recuperar el nexo entre los anteriores ámbitos, el laboral y el familiar. Partiendo de la vinculación entre dos unidades, la doméstica y la económica, una pregunta central es ¿por qué es importante la participación familiar en las distintas formas de producir de los pequeños establecimientos en la dinámica del mercado de trabajo? Para discutir esta pregunta se analizan dos tipos ideales de vinculación familia/trabajo a partir de una serie de entrevistas realizadas en micronegocios familiares en la Ciudad de México
La descentralización de la política pública de combate a la pobreza: Programa de desarrollo humano de oportunidades como experiencia de análisis 2002-2012
Una tarea esencial en el desenvolvimiento de las funciones del Estado es la generación de políticas públicas como agentes creadores de estabilidad social. Es en busca de dicha estabilidad que se diseñan programas de combate a la pobreza que a lo largo del tiempo pretendieron sanear los males sociales. En el contexto nacional se han instaurado cursos de acción como el Programa Nacional de Solidaridad (Pronasol), el Programa de Educación, Salud y Alimentación (Progresa) y en tiempos recientes el Programa de Desarrollo Humano Oportunidades, todos ellos con el fin de ser un anclaje seguro ante los vertiginosos cambios del mercado y males sociales. El presente trabajo toma como objeto de aplicación del conocimiento al Programa Oportunidades debido a su papel fundamental en el tratamiento a la pobreza y como referente de análisis en la construcción de una propuesta de descentralización. Para ello se efectúa la revisión de teorías como federalismo y descentralización, además de revisar los marcos de análisis referentes a las relaciones intergubernamentales (RIG´s), política pública y política social. Hablar de federalismo es hablar de la importancia que juegan los órdenes de gobierno en el sano desenvolvimiento de las funciones del Estado con el fin último de lograr el bien común
Cuban Land Use and Conservation, from Rainforests to Coral Reefs
Cuba is an ecological rarity in Latin America and the Caribbean. Its complex political and economic history shows limited disturbances, extinctions, pollution, and resource depletion by legal or de facto measures. Vast mangroves, wetlands, and forests play key roles in protecting biodiversity and reducing risks of hazards caused or aggravated by climate change. Cuba boasts coral reefs with some of the region’s greatest fish biomass and coral cover. Although Cuba has set aside major protected areas that safeguard a host of endemic species, its environment is by no means pristine. Its early history is one of deforestation and agricultural production for colonial and neo-colonial powers. Using remote sensing, we find Cuba’s land today is 45% devoted to agricultural, pasturage, and crop production. Roughly 77% of Cuba’s potential mangrove zone is presently in mangrove cover, much outside legal protection; this is likely the most intact Caribbean mangrove ecosystem and an important resource for coastal protection, fish nurseries, and wildlife habitat. Even the largest watersheds with the most agricultural land uses have a strong presence of forests, mangroves, and wetlands to buffer and filter runoff. This landscape could change with Cuba’s gradual reopening to foreign investment and growing popularity among tourists—trends that have devastated natural ecosystems throughout the Caribbean. Cuba is uniquely positioned to avoid and reverse ecosystem collapse if discontinuities between geopolitical and ecosystem functional units are be addressed, if protection and conservation of endemic species and ecosystems services accompany new development, and if a sound ecological restoration plan is enacted
Investment in Small Business among International Migrants in the Estado De México
This work analyzes the productive inversions of the international remittances, the constraints that the migrants face. A non-random sample of migrants that invested remittances in business is taken in the Estadode México. The results show various types of investments, in which have influence, the family, the migratory experiences, the previous experience in business, the knowledge they brought to the return. All of them want to find an income source and not migrate again, but is noted that only who have sustainable income business, are who can build better livelihoods, while owning an unstable business causes instability in the livelihood, as well as intentions to return to abroad, Duel features are also observed, and other traits
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