818 research outputs found
Predictive factors of biological senescence in patients with high cardiovascular risk: The CORDIOPREV study
El envejecimiento es un proceso fisiológico complejo que se produce a nivel celular, molecular y genético, y que se asocia a diversas patologías, entre las que destaca la enfermedad cardiovascular. Evidencias recientes sugieren que el acortamiento telomérico se considera un marcador independiente del aumento del riesgo de enfermedad coronaria. Una mejor comprensión de los mecanismos que subyacen a la senescencia biológica, destacando la inflamación crónica y el estrés oxidativo, puede permitir el desarrollo de nuevas estrategias terapéuticas que nos faciliten el manejo de las patologías asociadas al envejecimiento. Nuestra hipótesis pretende demostrar si el desarrollo de una herramienta de e- Health permite evaluar el grado de senescencia en pacientes con enfermedad cardiovascular establecida basados en aspectos clínicos, biológicos y genéticos del paciente.Nuestro objetivo principal es desarrollar una plataforma de e-Health que permita evaluar el grado de envejecimiento biológico en base al perfil clínico y biológico del paciente. Para desarrollar dicha plataforma analizaremos el patrón de senescencia biológica medido por la longitud de los telómeros, junto a parámetros de respuesta inflamatoria, marcadores de estrés oxidativo y marcadores genéticos en una población con enfermedad cardiovascular establecida de la cohorte del estudio CORDIOPREV (NCT00924937).Aging is a complex physiological process that occurs at the cellular, molecular and genetic levels, and is associated with various pathologies, among which cardiovascular disease stands out. Recent evidence suggests that telomere shortening is considered an independent marker of increased risk of coronary heart disease. A better understanding of the mechanisms underlying biological senescence, highlighting chronic inflammation and oxidative stress, may allow the development of new therapeutic strategies that facilitate the management of pathologies associated with aging. Our hypothesis aims to demonstrate whether the development of an e-Health tool allows evaluating the degree of senescence in patients with established cardiovascular disease based on clinical, biological and genetic aspects of the patient. Our main objective is to develop an e-Health platform that allows evaluating the degree of biological aging based on the clinical and biological profile of the patient. To develop this platform, we will analyze the biological senescence pattern measured by the length of telomeres, together with inflammatory response parameters, oxidative stress markers and genetic markers in a population with established cardiovascular disease from the CORDIOPREV study cohort (NCT00924937)
Analysis of Moon impact flashes detected during the 2012 and 2013 Perseids
We present the results of our Moon impact flashes detection campaigns
performed around the maximum activity period of the Perseid meteor shower in
2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in
2012 because of very unfavourable geometric conditions, but 12 of these were
confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and
9.3. A luminous efficiency of 1.8 10 has been estimated for
meteoroids from this stream. According to this value, impactor masses would
range between 1.9 and 190 g. In addition, we propose a criterion to establish,
from a statistical point of view, the likely origin of impact flashes recorded
on the lunar surface.Comment: Accepted for publication in Astronomy and Astrophysics on March 11,
201
Prácticas utilizadas actualmente por las PYMES costarricenses para definir los niveles de produccion, costos, ventas y precios de los productos y/o servicios
Proyecto de graduación (Licenciatura en Administración de Empresas. Enfasis en Finanzas) Instituto Tecnológico de Costa Rica, Escuela de Administración de Empresas, 2012.En Costa Rica, la mayor parte de la producción nacional es contribuida por las PyMES. Este sector económico es considerado generalmente como conservador en cuanto a su planificación se refiere, ya que produce con características similares a las del competidor y de acuerdo a la demanda de mercado, lo cual les dificulta en ocasiones innovar.
Tomando en cuenta el papel importante de las pequeñas y medianas empresas en la economía nacional, se realizó la presente investigación con el fin de identificar las prácticas utilizadas por las PyMES costarricenses para definir los niveles producción, costos, ventas y precios de los productos y/o servicios ofrecidos, así como la influencia que ejerce el entorno en su definición.
En otras palabras, conocer cómo cubrir los costos generados con las ventas y a partir de ese nivel generar la oferta de valor e identificar las principales limitaciones a las que se enfrentan al momento de incurrir en costos y determinar producción, ventas y precios conforma el análisis del punto de equilibrio.
Como parte de los resultados obtenidos de la muestra se logró identificar que parte de las prácticas más importantes de las PyMES costarricenses incluyen comparar lo presupuestado contra lo real, así como fijar los precios utilizando un porcentaje de ganancia por encima de los costos en que se ha incurrido. Adicionalmente, se identificó que la mayor parte de las organizaciones que colaboraron en el estudio son capaces de identificar el mínimo de ventas requerido para cubrir todos los costos operacionales
Influence of continental history on the ecological specialization and macroevolutionary processes in the mammalian assemblage of South America: Differences between small and large mammals
Background: This paper tests Vrba's resource-use hypothesis, which predicts that generalist
species have lower specialization and extinction rates than specialists, using the 879 species of
South American mammals. We tested several predictions about this hypothesis using the biomic
specialization index (BSI) for each species, which is based on its geographical range within different
climate-zones. The four predictions tested are: (1) there is a high frequency of species restricted
to a single biome, which henceforth are referred to as stenobiomic species, (2) certain clades are
more stenobiomic than others, (3) there is a higher proportion of biomic specialists in biomes that
underwent through major expansion-contraction alternation due to the glacial-interglacial cycles,
(4) certain combinations of inhabited biomes occur more frequently among species than do others.
Results: Our results are consistent with these predictions. (1) We found that 42 % of the species
inhabit only one biome. (2) There are more generalists among species of Carnivora than in clades
of herbivores. However, Artiodactyla, shows a distribution along the specialization gradient
different from the one expected. (3) Biomic specialists are predominant in tropical rainforest and
desert biomes. Nevertheless, we found some differences between small and large mammals in
relation to these results. Stenobiomic species of micromammalian clades are more abundant in
most biomes than expected by chance, while in the case of macromammalian clades stenobiomic
species are more frequent than expected in tropical rainforest, tropical deciduous woodland and
desert biomes only. (4) The most frequent combinations of inhabited biomes among the South
American mammals are those with few biomes, i.e., the ones that suffered a higher rate of
vicariance due to climatic cycles.
Conclusion: Our results agree with the resource-use hypothesis and, therefore, with a major role
of the past climatic changes as drivers of mammalian evolution. Nevertheless, deviations from the
expectations indicate the importance of differences in reproductive traits and paleobiogeographic
history for the macroevolutionary processes involved. In the case of South American mammals, the
Pliocene Great American Biotic Interchange strongly influences the ecological characteristics of this
assemblage. Furthermore, the Andes have acted as a fertile ground for speciation in environments
prone to vicariance. Finally, the micromammals appear as more prone to biomic specialization than
larger species. These factors are responsible for some of the differences found between South
America and Africa in the studied pattern. For example, the extensive South American mountain
ranges favour a higher number of combinations of inhabited biomes in comparison with Africa
SHORT COURSE 50M MALE FREESTYLE PERFORMANCE COMPARISON BETWEEN NATIONAL AND REGIONAL SPANISH SWIMMERS
We aimed to analyse and compare the race components of national (47) and regional (158) male swimmers taking part in 50 m freestyle short course event. The relative contribution of each component, the split differences and relative splits were considered. A swimming race analysis system and an automatic swimming performance analysis (ASPA) were applied in the study. National male swimmers obtained significantly shorter times than regional: T10, 3.65 ± 0.14 s vs 4.56 ± 0.43 s; T15, 6.11 ± 0.18 s vs 7.47 ± 0.62 s; TTV15m, 6.99 ± 0.22 s vs 8.42 ± 0.71 s; T50, 23.25 ± 0.57 s vs 27.70 ± 2.16 s; higher SR (cyc•min-1) 60.2 ± 4.13 vs 57.6 ± 5.51; longer SL(m) 1.97 ± 0.15 vs 1.78 ± 0.15; and higher SI(m2•s-1) 3.89 ± 0.36 vs 3.011 ± 0.37. Differences in performances between national and regional Spanish groups were explained by the absolute split times, stroke length and stroke index. These differences were not found analysing the relative splits and indicates a similar race strategy regardless of the swimmers level
Swimming with Swimsuit and Wetsuit at Typical vs. cold-water Temperatures (26 vs. 18 ℃)
The study aimed to compare three swimming conditions in a swimming flume with water at 26ºC (using swimsuit) and 18ºC (randomly with swimsuit and wetsuit). Seventeen swimmers (32.4±14.7 years old, 175.6±0.06cm height, and 70.4±9.8kg body mass) performed the three bouts until exhaustion at 400m front crawl pace (24h intervals). ANOVA repeated measures compared the experimental conditions. Swimming at 26ºC with swimsuit evidenced a higher metabolic demand (total energy expenditure; (E)), comparing to 18ºC swimsuit (p=0.05) and with 18ºC wetsuit (p=0.04). The 26ºC swimsuit condition presented higher peak oxygen uptake (VO2peak), blood lactate concentrations ([La-]peak), rate of perceived exertion (RPE), maximal heart rate (HRmax), anaerobic lactic energy (AnL), E, energy cost (C), VO2 amplitude (Ap), and stroke rate (SR), but lower stroke length (SL) and stroke index (SI) than 18ºC wetsuit. The 18ºC swimsuit condition (comparing to wetsuit) lead to higher V̇O2peak, [La-]peak, HRmax, E, C, Ap, and SR but lower SL and SI. Swimming at aerobic power intensity with swim and wetsuit at 18ºC does not induce physiologic and biomechanical disadvantages comparing to 26ºC, The results suggested that the use of wetsuit might increase performance at 18ºC water temperature for competitive master swimmers. Thus, its use is recommended in open water swimming competitions when the water temperature is 18-20ºC
Saccharomyces cerevisiae responds similarly to co-culture or to a fraction enriched in Metschnikowia pulcherrima extracellular vesicles
Postactivation potentiation in sprint swimming performance
Introduction: In sprint swimming, every instant is critical. Nowadays, is common to see how sprint swimmers prepare for racing by activating themselves on many different ways such as doing ballistic stretching, by increasing their breathing and heart rate, or by strongly clapping their chest or limbs. Therefore, it cannot be rejected the fact that sprint swimmers need to create an extra activation on their neuromuscular system in order to race at the best of their capacities. Many of those methods have been based on post-activation potentiation (PAP). A procedure which improves muscle contractility both in strength and speed through previously applying maximal or submaximal conditioning exercises on the muscle system. The aim of this study was testing different PAP protocols on sprint swimming performance. Methods: This study received the approval of the ethics committee of the research board’s university and all the protocols accomplished with the declaration of Helsinki regarding the use of human subjects. Thirty trained swimmers volunteered to participate on this study and signed informed consent. First of all, all the swimmers were obtained the maximal repetition lifting load (RM), through strength tests consisting on an incremental load repetition test both for lower and upper limbs. In order to obtain results related to specific swimming-movements, PAP methods were extrapolated from experimental conditions and tested on a swimming start performance. Free-weight load lifting and maximal eccentric flywheel contractions simulating the movement of a swimming start were tested. Kinetic and kinematic variables of performance were obtained through a dynamometer experimental block start station and by photogrammetry. Individual’s strength index were also discussed and related to the results. Finally, conditioning exercises simulating arm strokes in swimming through free-weight and eccentric flywheel were tested on the variables of competition of a swimming race. Results: Swimming starts were able of being improved through PAP as velocity at take-off was higher, specially after eccentric warm-up protocols. These improvements would come from improvements on the vertical vectors of force/impulse developed by the lower limbs on the block. In fact, stronger athletes seemed to react better to PAP protocols, possibly because myosin phosphorylation (main PAP precursor) is more frequent on type II fibers. The first meters of a swimming race might be improved by using PAP. However, some swimming patterns as stroke length might be deteriorated along the race. Conclusion: Fatigue and potentiation co-exists as responses of PAP, therefore, it generates very individualized responses, specially in males. Positive results might be obtained from applying PAP methods on the swimming start impulse although is still needed finding a suitable intensity for the conditioning exercises applied on upper limbs. Acknowledgements: DEP2014-59707-P: SWIM: Specific Water Innovative Measurements, applied to the development of International Swimmers in Short Swimming Events (50and100m).CTS-527: Actividad física y deportiva en el medio acuátic
Lower fatigue and faster recovery of ultra-short race-pace swimming training sessions
Ultra-short race-pace training (USRPT) is a high-intensity training modality used in swimming for the development of the specific race-technique. However, there is little information about the fatigue associated to this modality. In a crossover design, acute responses of two volume-equated sessions (1000-m) were compared on 14 national swimmers: i) USRPT: 20×50-m; ii) RPT: 10×100-m. Both protocols followed an equivalent work recovery ratio (1:1) based on individual 200-m race-pace. The swimming times and the arm-strokes count were monitored on each set and compared by mixed-models. Blood lactate [La-] and countermovement jump-height (CMJ) were compared within and between conditions 2 and 5 min after the protocols. The last bouts in RPT were 1.5–3% slower than the target pace, entailing an arm-strokes increase value of ~0.22 for every second increase in swimming time. USRPT produced lower [La-] ([Mean ± standard deviation], 2 min: 8.2±2.4 [p = 0.021]; 5 min: 6.9±2.8 mM/L [p = 0.008]), than RPT (2 min: 10.9±2.3; 5 min: 9.9±2.4 mM/L). CMJ was lowered at min 2 after RPT (-11.09%) and USRPT (-5.89%), but returned to the baseline in USRPT at min 5 of recovery (4.07%). In conclusion, lower fatigue and better recovery were achieved during USRPT compared to traditional high-volume set.CTS-52
Operaciones de cobertura con derivados financieros de la empresa comercializadora de Café Colombicafè S.A
La empresa “COLOMBICAFE S.A” (Comercializadora de café) en busca de la minimización de riesgos, posicionamiento de la empresa y apertura de mercados presenta un trabajo que contiene los resultados del seguimiento realizado en el segundo semestre del año 2010, sobre la estrategia de comercializar y aplicar los contratos de cobertura a futuro que demandan una estabilización del precio del café. El café es uno de los principales producto que se exportan en Colombia y gracias a él, nuestro país se encuentra posicionado como un gran productor del grano. Este producto es nuestro objeto de estudio y en consecuencia base de análisis del comportamiento del precio. Partiendo de una cotización en el mercado al día 18 de Octubre del 2010 (Día de apertura de negociación) la evolución del precio del contrato sobre el precio del grano identificado con el nemotécnico KC.Z10.E con vencimiento al 17 de Diciembre del 2010. Con el fin de determinar la línea del contrato se realizo seguimiento del comportamiento del mercado a través de análisis técnico y fundamental con corte a 20, 22,25 y 27 del mes de Octubre del 2010 y 3,5 y 8 del mes de Noviembre del 2010. Junto con el monitoreo realizado al contrato se realizo un seguimiento a las primas de las opciones con posición Call y Put a las mismas fechas tomando los precios de las primas de la Bolsa de New York. Complementariamente las primas se valoraron a precio de mercado, tomando como patrón la evaluación del mencionado subyacente. Realizando la aplicación el modelo de Black-Scholes con sensibilidad de las variables Delta, Gama, Vega Theta y Rho, basados en la volatilidad de los precios, las tasas libres de riesgos de los Bonos del Tesoro a 30 años, la maduración es decir los días desde la negociación del contrato hasta la fecha de vencimiento de este con un base de 351 datos tomados diariamente de los históricos del Grupo Aval
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