Plan prospectivo estrátegico 2012 de Napa -NTS : una visión prospectiva de la empresa NAPA NTS frente al TLC.

Tesis (Magíster en Administración de Empresas) -- Universidad del Norte. Programa de Maestría en Administración de Empresas, 2008.Teniendo en cuenta la permanente apertura de fronteras comerciales que se viene dando desde la década pasada, que ha llevado a la globalización de la economía, así como la gran dependencia de la empresa NAPA-NTS, de las relaciones comerciales binacionales entre Colombia Estados Unidos de América, por tener esta empresa el 85% de sus proveedores de repuestos originarios de ese país, se ha hecho necesario el análisis de los factores expuestos a cambios en la ecuación de negocios de NAPA-NTS, con la firma del tratado de libre comercio entre los dos países, mediante la realización de una prospectiva estratégica al año 2012. El objetivo principal de este trabajo es proponer un plan prospectivo para NAPA-NTS para el año 2012, mediante la metodología teórica para la construcción de prospectivas estratégicas y la utilización de los softwares MICMAC y MACTOR. El resultado obtenido en el proyecto fue el plan prospectivo de NAPA-NTS para el año 2012 con la suscripción del TLC entre Colombia y Estados Unidos de América, en el cual se consiguió la identificación de las variables claves del cambio, la descripción del eje estratégico de las variables claves del cambio, el Señalamiento de escenarios posibles prospectivos que puedan ser utilizados como la base del plan estratégico y la determinación de los actores claves que pueden generar un cambio en el nuevo ambiente de negocios de NAPA NTS con el TLC. Como conclusión del trabajo realizado, se determina la implementación de una estrategia de diferenciación, sobre la base de un producto de alta calidad apoyado sobre una cadena de distribución fortalecida y con territorios muy bien definidos y una estrategia de penetración del mercado consistente en incrementar la participación de la empresa con sus características de distribución comercial en los mercados en los que opera y con los productos actuales, es decir, en el desarrollo del negocio básico

Nuclear shape dependence of Gamow-Teller distributions in neutron-deficient Pb isotopes

We study Gamow-Teller strength distributions in the neutron-deficient even isotopes (184-194)Pb in a search for signatures of deformation. The microscopic formalism used is based on a deformed quasiparticle random phase approximation (QRPA) approach, which involves a self-consistent quasiparticle deformed Skyrme Hartree-Fock (HF) basis and residual spin-isospin forces in both the particle-hole and particle-particle channels. By analyzing the sensitivity of the Gamow-Teller strength distributions to the various ingredients in the formalism, we conclude that the beta-decay of these isotopes could be a useful tool to look for fingerprints of nuclear deformation.Comment: 20 pages, 11 figures. To be published in Physical Review

Gamow-Teller strength distributions in Xe isotopes

The energy distributions of the Gamow-Teller strength are studied for even-even Xe isotopes with mass numbers from 124 to 142. A self-consistent microscopic formalism is used to generate the single particle basis, using a deformed Skyrme Hartree-Fock mean field with pairing correlations in BCS approximation. The Gamow-Teller transitions are obtained within a quasiparticle random phase approximation (QRPA) approach using a residual spin-isospin interaction in the particle-hole and particle-particle channels. We then discuss the pairing BCS treatment and the determination of the ph and pp residual interaction coupling constants. We study the GT+ and GT- strength distributions for the equilibrium nuclear shapes, which are an essential information for studies of charge-exchange reactions and double-beta processes involving these isotopes.Comment: 15 pages, 5 figures. To appear in Phys Rev

Single- and low-lying-states dominance in two-neutrino double-beta decay

19 pages, 5 tables, 6 figures.--Available on line on Oct 30, 2008.--ArXiv pre-print available at: http://arxiv.org/abs/0811.0319A theoretical analysis of the single-state dominance hypothesis for the two-neutrino double-beta decay rates is performed on the examples of the double-beta decays of 100Mo, 116Cd and 128Te. We also test the validity of an extended low-lying-state dominance that takes into account the contributions of the low-lying excited states in the intermediate nucleus to the double-beta decay rates. This study has been accomplished for all the double-beta emitters for which we have experimental information on their half-lives. The theoretical framework is a proton–neutron quasiparticle random-phase approximation based on a deformed Skyrme Hartree–Fock mean field with pairing correlations. Our calculations indicate that there are no clear evidences for single- or low-lying-state dominance in the two-neutrino double-beta decay. Finally, we investigate the single-electron energy distributions of the outgoing electrons in the double-beta decay processes with an exact treatment of the energy denominators, which could help for a more comprehensive analysis of NEMO-3 data.This work was supported by Ministerio de Ciencia e Innovaci´on (Spain) under contract no. FIS2005-00640. It was also supported in part by the EU ILIAS project under contract RII3-CT-2004-506222. O M and R A R thank Ministerio de Ciencia e Innovaci´on (Spain) for financial support.Peer reviewe

Oxidative stress is tightly regulated by cytochrome c phosphorylation and respirasome factors in mitochondria

Respiratory cytochrome c has been found to be phosphorylated at tyrosine 97 in the postischemic brain upon neuroprotective insulin treatment, but how such posttranslational modification affects mitochondrial metabolism is unclear. Here, we report the structural features and functional behavior of a phosphomimetic cytochrome c mutant, which was generated by site-specific incorporation at position 97 of p-carboxymethyl-l-phenylalanine using the evolved tRNA synthetase method. We found that the point mutation does not alter the overall folding and heme environment of cytochrome c, but significantly affects the entire oxidative phosphorylation process. In fact, the electron donation rate of the mutant heme protein to cytochrome c oxidase, or complex IV, within respiratory supercomplexes was higher than that of the wild-type species, in agreement with the observed decrease in reactive oxygen species production. Direct contact of cytochrome c with the respiratory supercomplex factor HIGD1A (hypoxia-inducible domain family member 1A) is reported here, with the mutant heme protein exhibiting a lower affinity than the wild-type species. Interestingly, phosphomimetic cytochrome c also exhibited a lower caspase-3 activation activity. Altogether, these findings yield a better understanding of the molecular basis for mitochondrial metabolism in acute diseases, such as brain ischemia, and thus could allow the use of phosphomimetic cytochrome c as a neuroprotector with therapeutic applications.España, Junta de Andalucía BIO-198España MINECO BFU2015-71017/BM

Structural and functional characterization of phosphomimetic mutants of cytochrome c at threonine 28 and serine 47

Protein function is frequently modulated by post-translational modifications of specific residues. Cytochrome c, in particular, is phosphorylated in vivo at threonine 28 and serine 47. However, the effect of such modifications on the physiological functions of cytochrome c – namely, the transfer of electrons in the respiratory electron transport chain and the triggering of programmed cell death – is still unknown. Here we replace each of these two residues by aspartate, in order to mimic phosphorylation, and report the structural and functional changes in the resulting cytochrome c variants. We find that the T28D mutant causes a 30-mV decrease on the midpoint redox potential and lowers the affinity for the distal site of Arabidopsis thaliana cytochrome c1 in complex III. Both the T28D and S47D variants display a higher efficiency as electron donors for the cytochrome c oxidase activity of complex IV. In both protein mutants, the peroxidase activity is significantly higher, which is related to the ability of cytochrome c to leave the mitochondria and reach the cytoplasm. We also find that both mutations at serine 47 (S47D and S47A) impair the ability of cytoplasmic cytochrome c to activate the caspases cascade, which is essential for triggering programmed cell death.Peer reviewe

beta-decay in neutron-deficient Hg, Pb, and Po isotopes

The effect of nuclear deformation on the energy distributions of the Gamow-Teller strength is studied in neutron-deficient Hg, Pb, and Po even isotopes. The theoretical framework is based on a self-consistent deformed Skyrme Hartree-Fock mean field with pairing correlations between like nucleons in BCS approximation and residual spin-isospin interactions treated in the proton-neutron quasiparticle random phase approximation. After a systematic study of the Gamow-Teller strength distributions in the low excitation energy region, relevant for beta-decay, we have identified the best candidates to look for deformation signatures in their beta-decay patterns. beta+ half-lives and total Gamow-Teller strengths B(GT+) and B(GT-) are analyzed as well.Comment: 18 pages, 7 figures, to appear in Phys. Rev.

Model-free Rheo-AFM probes the viscoelasticity of tunable DNA soft colloids

Atomic force microscopy rheological measurements (Rheo‐AFM) of the linear viscoelastic properties of single, charged colloids having a star‐like architecture with a hard core and an extended, deformable double‐stranded DNA (dsDNA) corona dispersed in aqueous saline solutions are reported. This is achieved by analyzing indentation and relaxation experiments performed on individual colloidal particles by means of a novel model‐free Fourier transform method that allows a direct evaluation of the frequency‐dependent linear viscoelastic moduli of the system under investigation. The method provides results that are consistent with those obtained via a conventional fitting procedure of the force‐relaxation curves based on a modified Maxwell model. The outcomes show a pronounced softening of the dsDNA colloids, which is described by an exponential decay of both the Young's and the storage modulus as a function of the salt concentration within the dispersing medium. The strong softening is related to a critical reduction of the size of the dsDNA corona, down to ≈70% of its size in a salt‐free solution. This can be correlated to significant topological changes of the dense star‐like polyelectrolyte forming the corona, which are induced by variations in the density profile of the counterions. Similarly, a significant reduction of the stiffness is obtained by increasing the length of the dsDNA chains, which we attribute to a reduction of the DNA density in the outer region of the corona

Determinación de pigmentos en orégano (Poliomintha bustamantaB. L. Turner.) en dos condiciones de crecimiento.

El “orégano de Nuevo León” Poliomintha bustamanta B. L Turner., es una de las especies de orégano más importantes del País, apreciado y comercializado, por su uso como condimento y para la producción de aceites esenciales. Se encuentra en forma silvestre en las regiones áridas y semiáridas, cuyos ambientes es recolectada para su aprovechamiento y poco se ha cuidado su manejo y recuperación natural, es necesario realizar investigaciones encaminadas a establecer cultivos comerciales de esta planta. El objetivo fue evaluar en espectrometría de luz visible el contenido de pigmentos de la hoja bajo dos condiciones de crecimiento. Se colectaron hojas de orégano de plantas silvestres en el municipio de Higueras, N.L., y de plántulas de invernadero. El orégano silvestre, mostró una mayor concentración de pigmentos que el de invernadero. Estos resultados muestran diferencia significativa (P<0.01) entre el origen del orégano y el estado de la muestra, observándose en las muestras secas de orégano silvestre el mayor contendido de clorofila total, clorofila a, carotenos totales y carotenos amarillos. Mientras que las muestras secas de orégano de invernadero presentaron el mayor contenido de carotenos rojos. El cultivo de Orégano en invernadero presenta una menor concentración de pigmentos que el orégano silvestre

Structural basis of mitochondrial dysfunction in response to cytochrome c phosphorylation at tyrosine 48

Regulation of mitochondrial activity allows cells to adapt to changing conditions and to control oxidative stress, and its dysfunction can lead to hypoxia-dependent pathologies such as ischemia and cancer. Although cytochrome c phosphorylation—in particular, at tyrosine 48—is a key modulator of mitochondrial signaling, its action and molecular basis remain unknown. Here we mimic phosphorylation of cytochrome c by replacing tyrosine 48 with p-carboxy-methyl-L-phenylalanine (pCMF). The NMR structure of the resulting mutant reveals significant conformational shifts and enhanced dynamics around pCMF that could explain changes observed in its functionality: The phosphomimetic mutation impairs cytochrome c diffusion between respiratory complexes, enhances hemeprotein peroxidase and reactive oxygen species scavenging activities, and hinders caspase-dependent apoptosis. Our findings provide a framework to further investigate the modulation of mitochondrial activity by phosphorylated cytochrome c and to develop novel therapeutic approaches based on its prosurvival effects.Financial support was provided by the Spanish Ministry of Economy and Competitiveness (Grants BFU2015-71017-P/BMC and BFU2015-19451/BMC, cofounded by FEDER EU), European Union (Bio-MR-00130 and CALIPSO-312284), Ramon Areces Foundation, and Andalusian Government (BIO198). B.M.-B. was awarded a PhD fellowship from the Spanish Ministry of Education (AP2009-4092) and a short-term traveling fellowship from the European Bio-NMR Project. A.G.-C. was awarded a PhD fellowship from the CSIC (JaePre-2011-01248).Peer reviewe