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Search Results: 1 - 10 of 210749 matches for " Nadia; Valdez L "
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EFECTO DEL CONSUMO DE HARINA DE MAíZ FORTIFICADA CON ACIDO FóLICO SOBRE LOS NIVELES DE FOLATOS SANGUíNEOS EN MUJERES DE EDAD FéRTIL
Sánchez P,Maria Alejandra; Esmer S,María del Carmen; Martínez de V,Laura; Varela G,Nadia; Valdez L,Ramón; Torres S,Rosario; López O,Rocío; Villarreal P,Jesús;
Revista chilena de nutrición , 2011, DOI: 10.4067/S0717-75182011000200008
Abstract: fortification of foods is now widely used to prevent folate deficiency. folic acid has been added to corn flour and its efficacy in the prevention of ntd has been proved. the aim of this study was to compare the effect of the intake of fortified corn-flour versus non fortified flour and to folic acid supplement, on blood folate levels in women of childbearing age. forty-five women were randomized into three groups according to: (a) use of fortified flour (n=18), (b) non-fortified flour (n=17); (c) supplementation with 5 mg of oralfolic acid (n=10). all females answer a dietary and anthropometric questionnaire applied once a month during three months. blood red cell (ie) and plasmatic (p) folate were measured at the beginning and at the end of the study; also the dna analysis for the 677t mutation was performed. the corn flour was provided to groups a and b during three months, to be consumed as eight tortillas daily. group c received 5.0 mg tablet of folic acid (valdecasas?), once per week, during three months. ie and p folate and hematocrito were significantly increased in women from group c (p<0.05). only plasmatic folic acid levels were significantly increased in women from groups a and b. genotype distribution was: 15.6% homozygous tt, 42.2% c/c and 42.2% ct. weekly administration of 5.0 mg of folic acid is an effective way to increase blood folate levels and shows to be more efficient than fortified corn flour.
Leyendas de fantasmas del centro histórico de Puebla, México.?Un recurso complementario de atracción turística?
Valdez,Raúl;
Estudios y perspectivas en turismo , 2010,
Abstract: many historical sites, heritage buildings and geographical regions around the world are linked to popular legends related to ghosts and other supernatural phenomena. different studies demonstrate that these phenomena have been utilized as additional features to increate the attraction of these sites for tourist. in spite of using ghosts and specters o other supernatural phenomena however, to add interest for historical or heritage sites, this practice has not been widely studied from the perspective of tourist satisfaction. after an exploratory study realized with the help of historians, city chroniclers, tourist guides and employees working in the historical district of the city of puebla, mexico, fifteen civil and religious heritage buildings linked to legends of ghosts and supernatural phenomena were identified. this study supports the creation and promotion of three tourist routes containing the most famous historical buildings linked to legends of ghosts and supernatural phenomena in order to increase their interest for tourists. finally, this paper proposes the need to undertake more formal research focused on assessing the level of tourist gratification resulting from visits to heritage buildings and sites linked to supernatural phenomena.
Leyendas de fantasmas del centro histórico de Puebla, México. Un recurso complementario de atracción turística? Ghost Legends from the Historical District of Puebla, Mexico: A Complementary Tourist Attraction?
Raúl Valdez
Estudios y perspectivas en turismo , 2010,
Abstract: Diversos estudios demuestran que existen sitios, conjuntos arquitectónicos, o regiones que suscitan el interés de los turistas por estar ligados a leyendas populares sobre fenómenos sobrenaturales que les confieren un encanto especial. Sin embargo, hasta el presente, no existen estudios que permitan determinar la aceptación de los turistas al hecho de incorporar las leyendas populares como atractivos complementarios de lugares, inmuebles o monumentos donde se dice tienen lugar la aparición de fantasmas o de fenómenos sobrenaturales. Mediante un estudio exploratorio realizado entre historiadores, cronistas, guías turísticos calificados y empleados de inmuebles de carácter patrimonial ubicados en el centro histórico de la ciudad de Puebla, en México, se identificaron 15 edificios civiles y religiosos que podrían utilizar las leyendas sobre la aparición de fantasmas y la existencia de fenómenos sobrenaturales para incrementar su atractivo turístico cultural. Como resultado del estudio, se sugiere la creación de 3 recorridos turísticos por el centro histórico de la ciudad de Puebla donde se incluyen los 15 inmuebles más ligados a leyendas de fantasmas y de sucesos sobrenaturales que pudieran agregarse a la oferta turística cultural de la ciudad de Puebla. Finalmente, este trabajo plantea la necesidad de realizar investigaciones formales orientadas a evaluar la utilización de las leyendas sobre fantasmas y sucesos sobrenaturales desde diferentes perspectivas, entre las cuales, destaca la satisfacción obtenida por los turistas ante este tipo de atracciones complementarias a la visita turística de sitios y monumentos patrimoniales. Many historical sites, heritage buildings and geographical regions around the world are linked to popular legends related to ghosts and other supernatural phenomena. Different studies demonstrate that these phenomena have been utilized as additional features to increate the attraction of these sites for tourist. In spite of using ghosts and specters o other supernatural phenomena however, to add interest for historical or heritage sites, this practice has not been widely studied from the perspective of tourist satisfaction. After an exploratory study realized with the help of historians, city chroniclers, tourist guides and employees working in the historical district of the city of Puebla, Mexico, fifteen civil and religious heritage buildings linked to legends of ghosts and supernatural phenomena were identified. This study supports the creation and promotion of three tourist routes containing the most famous historical buildings
La gota de agua
José L. Valdez Medina
Ciencia Ergo Sum , 2002,
Abstract:
H_2 emission arises outside photodissociation regions in ultra-luminous infrared galaxies
Nadia L. Zakamska
Physics , 2010, DOI: 10.1038/nature09037
Abstract: Ultra-luminous infrared galaxies are among the most luminous objects in the local universe and are thought to be powered by intense star formation. It has been shown that in these objects the rotational spectral lines of molecular hydrogen observed at mid-infrared wavelengths are not affected by dust obscuration, leaving unresolved the source of excitation of this emission. Here I report an analysis of archival Spitzer Space Telescope data on ultra-luminous infrared galaxies and demonstrate that star formation regions are buried inside optically thick clouds of gas and dust, so that dust obscuration affects star-formation indicators but not molecular hydrogen. I thereby establish that the emission of H_2 is not co-spatial with the buried starburst activity and originates outside the obscured regions. This is rather surprising in light of the standard view that H_2 emission is directly associated with star-formation activity. Instead, I propose that H_2 emission in these objects traces shocks in the surrounding material, which are in turn excited by interactions with nearby galaxies, and that powerful large-scale shocks cooling by means of H_2 emission may be much more common than previously thought. In the early universe, a boost in H_2 emission by this process may speed up the cooling of matter as it collapsed to form the first stars and galaxies and would make these first structures more readily observable.
Theory of Special Relativity
Nadia L. Zakamska
Physics , 2015,
Abstract: Special Relativity is taught to physics sophomores at Johns Hopkins University in a series of eight lectures. Lecture 1 covers the principle of relativity and the derivation of the Lorentz transform. Lecture 2 covers length contraction and time dilation. Lecture 3 covers Minkowski diagrams, simultaneous events and causally connected events, as well as velocity transforms. Lecture 4 covers energy and momentum of particles and introduces 4-vectors. Lecture 5 covers energy and momentum of photons and collision problems. Lecture 6 covers Doppler effect and aberration. Lecture 7 covers relativistic dynamics. Optional Lecture 8 covers field transforms. The main purpose of these notes is to introduce 4-vectors and the matrix notation and to demonstrate their use in solving standard problems in Special Relativity. The pre-requisites for the class are calculus-based Classical Mechanics and Electricity & Magnetism, and Linear Algebra is highly recommended.
Habitat use by desert bighorn sheep in sonora, México
Tarango, L. A.,Krausman, R.,Valdez, R.
Pirineos : Revista de Ecología de Monta?a , 2002,
Abstract: The use of habitat components by desert bighorn sheep (Ovis canadensis) was examined to explain sexual segregation of sheep in Sierra el Viejo, Sonora, Mexico. We evaluated 265 plots used by bighorns and 278 random plots from April 1997 to December 1998. Groups of segregated males and females preferred the elephant tree (Bursera microphylla)-salvia (Salvia mellifera)-limber bush (Jatropha cuneata) association (ESL) and avoided the foothill palo verde (Cercidium microphyllum)-desert ironwood (Olneya tesota) association (FDD. Segregated females selected the ocotillo (Fouquieria splendens)-desert agave (Agave spp.yhop bush (Dodonoea viscosa) (OAH) vegetation association, formed larger groups, were closer to escape terrain, and occupied more rugged areas during autumn and spring than males. Segregated females selected areas that provided more opportunities to evade predation than did males. [fr] Nous avons étudié les différents composants de l'utilisation de l'habitat par le mouflon américain (Ovis canadensis) afin d'expliquer sa ségrégation sexuelle dans la Sierra el Viejo, à Sonora, Mexique. D'avril 1997 à Décembre 1998, on a évalué 265 parcelles utilisées par les mouflons et 278 parcelles au hasard. Différents groupes séparés de males et femelles préféraient l'association (ESL) formée par l'arbre Bursera microphylla, la sauge (Salvia mellifera) et l'arbuste Jatropa cuneata et ils évitaient l'association (FDD composée du Cercidium microphyllum et /'Olneya tesota. Les groupes de femelles sélectionaient l'association végétale (OAH) de Fouquieria splendens. Agave spp. et l'arbuste Dodonoea viscosa; et par rapport aux males, elles formaient de plus grands groupes, étaient plus proches de la zone de fuite et elles occupaient des terrains plus accidentés en automne et au printemps. Les groupes de femelles, plus que les males, cherchaient des zones avec moins de risque de prédation. [es] Se examinó el uso del hábitat del muflón americano Ovis canadensis para explicar su segregación sexual en Sierra el Viejo, Sonora, Méjico. Se establecieron 265 parcelas usadas por el muflón y 278 tomadas al azar, desde abril de 1997 hasta diciembre de 1998. Los grupos segregados de machos y hembras prefirieron la asociación (ESL) torote blanco (Bursera microphyllaj-sn/z^m (Salvia mellifera)- sangreado (Jatropha cuneata) y evitaron la asociación (FDI) palo verde (Cercidium microphyllum)-palo fierro (Olneya tesota). Los grupos de hembras seleccionaron la asociación ocotillo (Fouquieria splendens)-ágave (Agave spp.)- chirca (Dodonaea viscosa) (OAH); formaron grandes grupos, estando
CHEMICAL EVOLUTION MODEL OF M33
F. Robles-Valdez,L. Carigi
Revista mexicana de astronomía y astrofísica , 2011,
Abstract:
Models of Galaxy Clusters with Thermal Conduction
Nadia L. Zakamska,Ramesh Narayan
Physics , 2002, DOI: 10.1086/344641
Abstract: We present a simple model of hot gas in galaxy clusters, assuming hydrostatic equilibrium and energy balance between radiative cooling and thermal conduction. For five clusters, A1795, A1835, A2199, A2390 and RXJ1347.5-1145, the model gives a good description of the observed radial profiles of electron density and temperature, provided we take the thermal conductivity $\kappa$ to be about 30% of the Spitzer conductivity. Since the required $\kappa$ is consistent with the recent theoretical estimate of Narayan & Medvedev (2001) for a turbulent magnetized plasma, we consider a conduction-based equilibrium model to be viable for these clusters. We further show that the hot gas is thermally stable because of the presence of conduction. For five other clusters, A2052, A2597, Hydra A, Ser 159-03 and 3C295, the model requires unphysically large values of $\kappa$ to fit the data. These clusters must have some additional source of heat, most likely an active galactic nucleus since all the clusters have strong radio galaxies at their centers. We suggest that thermal conduction, though not dominant in these clusters, may nevertheless play a significant role by preventing the gas from becoming thermally unstable.
Amphibia, Anura, Cycloramphidae, Proceratophrys avelinoi Mercadal de Barrio and Barrio, 1993: Distribution extension and distribution map
Carosini, A.,Pérez, P.,Ortiz, M. L.,Valdez, L.
Check List , 2010,
Abstract: Proceratophrys avelinoi was only known from one reserve in Paraguay, located in the southern region of thecountry, in the Itapúa department. Herein we report the third record for the country which would be the first record forthe department of Alto Parana department extending the distribution of this species in the country over 200 km; we alsopresent the P. avelinoi distribution map in Paraguay.
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