Luis Palacios - Academia.edu (original) (raw)

Papers by Luis Palacios

Afin de determiner le stress de travail chez les personnels de l'armee Venezuelienne, une etu... more Afin de determiner le stress de travail chez les personnels de l'armee Venezuelienne, une etude explicative, non experimentale, mais retrospective et comparative fut menee. Participent a l'etude 194 personnes (officiers, sous-officiers, engages et hommes du rang) avec des niveaux moderes de stress predominant chez chacun d'eux. Les manifestations cliniques sont la fatigue chez les sous-officiers, l'inquietude dans les autres groupes. Habituellement le controle de l anxiete est effectue par le repos chez les officiers, les sous-officiers et les engages, l'activite physique chez les appeles. Les facteurs generateurs de stress sont ressentis comme dus a la pression familiale provoquee par les longues journees de travail avec de nombreuses heures supplementaires chez les officiers et les sous-officiers; chez les appeles, un manque de concertation directe avec leur superieur, se traduit par de nouvelles charges et sollicitations qui ont qu'ils depensent plus de te...

The paper describes a novel and unified approach to develop a fully detailed operations model und... more The paper describes a novel and unified approach to develop a fully detailed operations model under the new competitive framework among electric companies. The competitive behavior of the electric energy market is represented by the formulation of a set of equilibrium constraints that reproduce the optimality conditions for maximizing the profit of strategic firms. At the same time the system operation functions, such as probabilistic hydrothermal scheduling, thermal unit commitment, seasonal and daily operation of pumped units are considered. A scenario tree explicitly models stochastic natural inflows. The model has been implemented in GAMS, an algebraic modeling language specially suited for optimization problems. This model has being applied to the Spanish electric energy system as a case study in the new competitive framework.

We presented a report of infrequent surgical pathology and description of a clinical case seen in... more We presented a report of infrequent surgical pathology and description of a clinical case seen in service of mammary pathology of Oncological Hospital Father...

Cogent Food & Agriculture

Irrigated agriculture is a key activity for the long-term survival of humanenvironmental systems ... more Irrigated agriculture is a key activity for the long-term survival of humanenvironmental systems and the assessment of agricultural sustainability has been gaining increasing relevance. In spite of several proposals developed, there is not a holistic approach that can be generally applied to assess sustainability of irrigated agricultural areas. In this paper we present a framework and associated indicators for the assessment of sustainability of irrigated agricultural systems in different contexts and locations. The framework covers four main sustainability dimensions: environmental integrity, economic resilience and profitability, social wellbeing and good governance. This approach was tested in 10 agricultural areas in eight different countries that represent a wide variety of situations in terms of agricultural development, environmental conditions, socioeconomic settings and political contexts, but that share the fact that water use is a critical aspect for agricultural development. The obtained results illustrate the usefulness of the proposed framework to obtain a holistic picture of sustainability in irrigated agriculture areas, even in situations

Pediatr Edicion Int, Jun 1, 1999

Revista Venezolana De Oncologia, Jun 1, 2009

... Luis Palacios F, Carmen Suárez, Alirio Mijares, Raúl Vera G, Beatriz Delgado. ... Los contrat... more ... Luis Palacios F, Carmen Suárez, Alirio Mijares, Raúl Vera G, Beatriz Delgado. ... Los contrates de las variables nominales se basaron en la prueba Chi-cuadrado de Pearson con corrección de Yates, esta se aplicó en el caso de las frecuencias con celdas menores de 5. ...

Estratos, 2000

Acceso de usuarios registrados. Acceso de usuarios registrados Usuario Contraseña. ...

Physiological Zoology, 1997

Oxygen stores available for aerobic diving were studied in the freshwater turtle (Mauremys caspic... more Oxygen stores available for aerobic diving were studied in the freshwater turtle (Mauremys caspica leprosa) at three constant body temperatures (15', 250, and 350C) and during the thermal transient (30'- 150C) induced by immersion in cold water. The term "aerobic dive limit" has been ...

Physiological Zoology, 1996

Abstract During the breeding season, wild quail (Coturnix coturnix coturnix) rise from an altitud... more Abstract During the breeding season, wild quail (Coturnix coturnix coturnix) rise from an altitude of 200 m to 1,200 m to feed, covering a distance of approximately 225 km in 2 mo. Blood 02 transport properties were studied in adult male specimens captured at 200 m, 800 m, and 1,200 m. ...

Salus Militiae, Dec 1, 2002

Revista Urbana, Jul 1, 2001

Bol Acad Nac Med B Aires, Dec 1, 1991

The objective of this study was to compare and evaluate the effectiveness of three protocols of i... more The objective of this study was to compare and evaluate the effectiveness of three protocols of intermittent exposure to simulated altitude (hypobaric hypoxia). This was done in order to determine the shortest protocol in which hematological changes were induced. In addition to having some potential therapeutic applications, these protocols have also been used to pre-acclimation of climbers to altitude, and to improve the performance capacity of athletes. These applications are supported by the available evidence that living in hypoxia while training in normoxia is probably more effective than training and living in hypoxia. Three protocols of different duration (days) and exposure (hours) at a simulated altitude of 4,000-5,500m (462-379 Torr) were compared (Protocol A: 17 days and 60 hours; Protocol B: 9 days and 31 hours; and Protocol C: 21 days and 14 hours). The three experimental procedures showed to effectively elicit a significant increase (p<0.05) in packed cell volume (m...

General pharmacology, 1992

1. The effects of two anaesthetics, sodium pentobarbital and urethane, and the effects of anaesth... more 1. The effects of two anaesthetics, sodium pentobarbital and urethane, and the effects of anaesthesia-associated hypothermia on acid-base status and blood gases were studied in rats without assisted ventilation. 2. Manipulation of conscious rats produces a progressive increase in arterial lactate associated with slight hyperventilation. 3. Sodium pentobarbital anaesthesia produces mild respiratory acidosis accompanied by increase in lactate arterial values. Urethane anaesthesia leads to partially compensated metabolic acidosis. 4. Hypothermia reduces metabolic acidosis and hypercapnia induced by sodium pentobarbital anaesthesia. No difference between hypothermic and normothermic values was observed in urethane anaesthesia.

Journal of applied physiology (Bethesda, Md. : 1985), 1996

The interactions between components that contribute to acid-base homeostasis were studied in the ... more The interactions between components that contribute to acid-base homeostasis were studied in the first steps of acute hypothermia [body temperature (Tb) 37-31 degrees C] in awake unrestrained rats as an experimental model of accidental hypothermia in mammals. The concurrent changes in blood gases, plasma ions, and plasma protein concentrations in arterial blood were analyzed. Acute decreases in Tb decreased PCO2 and increased pH. The ratio of Na+ concentration to Cl- concentration increased at 35-33 degrees C Tb, leading to an increase in the plasma strong ion difference ([SID]). These increases were transient, and levels returned to baseline at lower Tb (31 degrees C). Lack of change in hematocrit, hemoglobin, plasma osmolality, or plasma protein concentration indicated stability in plasma volume. Therefore, [SID] changes were related to ionic shifts with respect to the extravascular space and not to ionic depletion. A feasible role in this ionic exchange for contracting skeletal m...

Respiration physiology, 1995

Blood acid-base changes were studied during acute hypothermia (4-6 h) induced by cold exposure in... more Blood acid-base changes were studied during acute hypothermia (4-6 h) induced by cold exposure in the unanesthetized rat. Stewart's quantitative analysis was applied as a complementary approach to determine the relative contributions of several non-respiratory components to the arterial acid-base response. Acute decrease in body temperature (TB) lowered PaCO2 (32.5 to 14.5 mmHg) and [HCO3-]a(24.20 mEq/L to 17.56 mEq/L), increased pHa (7.481 to 7.608) and diminished the [OH-]/[H+] ratio, but had no significant effect on [SID] or [Atot], although both total phosphorus [PT] and inorganic phosphate [Pi] increased. The acid-base changes found were intermediate between those predicted by alpha-stat and pH-stat hypotheses. Deviation from the regulative alpha-imidazole strategy was more apparent in the plasma than in the intraerythrocyte compartment. We conclude that blood pH changes observed were mainly caused by increased relative ventilation (lung ventilation per unit of CO2 removed)...

Journal Oral Of Research, 2012

Tasa de supervivencia de implantes cortos y largos en población chilena. Survival rate of short a... more Tasa de supervivencia de implantes cortos y largos en población chilena. Survival rate of short and long dental implants in chilean population. Resumen: Introducción: El uso de implantes cortos, se asocia a tasas de supervivencia menores que a las de implantes largos. Sin embargo, estudios recientes muestran resultados disímiles. El objetivo de este trabajo es evaluar la supervivencia de implantes cortos y largos durante un período de 12 años. Metodología: Estudio de supervivencia de una cohorte retrospectiva, en una muestra de 78 individuos desdentados tratados consecutivamente cada uno con implantes cortos y largos entre 1998 y el 2008, siguiendo el protocolo Branemark, insertándose 548 implantes (Branemark Sistem); 396 largos (>10 mm. con un diámetro de 3,75-4,0 mm.) y 152 implantes cortos (<8,5 mm. con un diámetro de 3,75-4,0 mm.). En 377 implantes, la superficie fue maquinada, y en 171 oxidizada. El análisis de los datos se realizó con el software SPSS 15.0. Una p<0,05 se consideró significativa. Resultados: La tasa de supervivencia para los implantes cortos fue de 77%; mientras para los implantes largos fue un 94.9%. la comparación entre ambas mediante el test de Mantel y Cox resultó significativa. Conclusiones: Aparentemente la longitud implantes se relaciona con su supervivencia. Estudios prospectivos deberían focalizarse en determinar factores de riesgo en falla de oseointegración.