l estudio de la vegetación tropical de México muestra un sesgo notable hacia las regiones más húmedas de su vertiente atlántica. Por lo tanto, la información disponible para la vegetación de las regiones estacionalmente secas, localizadas principalmente a lo largo del litoral pacífico del 19 Resumen: En este estudio se describe la estructura, la composición florística y los patrones de diversidad de la selva baja caducifolia del Cerro Verde, localizado en Nizanda (Istmo de Tehuantepec, Oaxaca, México). En 30 parcelas de 100 m 2 se censaron las plantas leñosas con DAP ≥ 1 cm (estrato alto), y en cinco subcuadros de 4 m 2 dentro de cada una se censaron las plantas con DAP < 1 cm, pero con altura > 30 cm (estrato bajo). Se encontraron 194 especies distribuidas en 52 familias. La riqueza de especies fue idéntica en ambos estratos (145 especies), y cada uno aportó de manera exclusiva ca. 25% de la riqueza total registrada. Leguminosae fue la familia más rica en especies (27), seguida por Asteraceae (20) y Euphorbiaceae (18). Las especies más frecuentes fueron Bursera simaruba + B. aff. cinerea (no distinguidas en el campo), Euphorbia schlechtendalii, Pilosocereus collinsii y Capparis verrucosa. La riqueza específica promedio por cuadro fue de 30 especies. Los índices basados en la riqueza y la abundancia de las especies (Berger-Parker = 0.20; Simpson = 0.09; α de Fisher = 9.47; Shannon = 2.78; equitatividad = 0.82) indican una alta diversidad y una consecuente baja dominancia en esta selva. Los valores extrapolados mostraron una densidad total (estratos alto + bajo) de 23,950 ind. ha -1 (830 ind. ha -1 con DAP ≥ 10 cm), una cobertura de 446.7%, y un área basal de 53 m 2 ha -1 . La altura promedio del 10% de los árboles más altos fue 9.1 m. La estructura de la selva baja del Cerro Verde es semejante a la de otras comunidades vegetales del trópico seco de México y denota un buen estado de conservación. Este hecho, aunado a su particular composición florística, enfatiza la pertinencia de su conservación formal. Palabras clave: área basal, análisis estructural, bosque tropical caducifolio, cobertura, densidad, florística, Istmo de Tehuantepec, vegetación tropical. Abstract:In this study we describe the structure, floristic composition, and diversity of the tropical dry forest established on the Cerro Verde (Verde Hill), located at Nizanda (Isthmus of Tehuantepec, Oaxaca, Mexico). We censused woody plants with DBH ≥ 1 cm (upper stratum) present in 30 100-m 2 plots, and in five 4-m 2 subplots within each of them, those plants with height > 30 cm but < 1 cm DBH (lower stratum). A total of 194 species belonging to 52 families were recorded. Species richness was identical in both strata (145 species), each contributing exclusively with ca. 25% of total recorded richness. Leguminosae was the most speciose family (27), followed by Asteraceae (20) and Euphorbiaceae (18). The most frequent species were Bursera simaruba + B. aff. cinerea (not distinguished in the field), Euphorbia schlechtendalii, Pilosocereus collinsii and Cappari...

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Performance is usually assessed by simple indices stemming from cardiac and respiratory data measured during graded exercise test. The goal of this study is to characterize the indices produced by a dynamical analysis of HR and VO 2 for different effort test protocols, and to estimate the construct validity of these new dynamical indices by testing their links with their standard counterparts. Therefore, two groups of 32 and 14 athletes from two different cohorts performed two different graded exercise testing before and after a period of training or deconditioning. Heart rate (HR) and oxygen consumption (VO 2) were measured. The new dynamical indices were the value without effort, the characteristic time and the amplitude (gain) of the HR and VO 2 response to the effort. The gain of HR was moderately to strongly associated with other performance indices, while the gain for VO 2 increased with training and decreased with deconditioning with an effect size slightly higher than VO 2 max. Dynamical analysis performed on the first 2/3 of the effort tests showed similar patterns than the analysis of the entire effort tests, which could be useful to assess individuals who cannot perform full effort tests. In conclusion, the dynamical analysis of HR and VO 2 obtained during effort test, especially through the estimation of the gain, provides a good characterization of physical performance, robust to less stringent effort test conditions. Characterization of Heart Rate (HR) and oxygen consumption (VO 2) related to mechanical power (i.e., speed or power) during standardized graded exercise test (GET) is an unavoidable step in current athlete's performances assessment 1. These two measurements are also classically used in the scientific field of sport studies as one of the main physiological outputs to characterize evolution of athlete's performance over time 2-4. Current analysis of these parameters is based on two radically different approaches. The first is the use of standard techniques, easily applicable and extensively used. The most common index to characterize the HR recovery is the Heart Resting Rate (HRR) 5 , commonly defined as the difference between HR at the onset of recovery and HR one minute after. This characterization is known to be a good predictor of cardiac problems in medicine 5 , and is an interesting indicator of physical condition and training 6. The maximum rate of HR increase (rHRI) is a recent indicator showing correlation with fatigue and training in various studies 6. This first type of approaches to characterize HR dynamics suffers from two important drawbacks. First, these measurements mix the amplitude of the HR response to effort with its temporal shape. For instance, someone reaching a maximum heart rate of 190 beat/minute and decreasing to 100 beat/min in one minute will have the same HRR as another person reaching 150 beats/minute and decreasing to 60 beats/minute in one minute, although the HR dynamic is different. Secondly and more importantly, they use only a small fraction of the inf...

Resting energy expenditure (REE) is determined mainly by fat-free mass (FFM). FFM depends also on daily physical activity. REE normally decreases with increased age due to decreases in FFM and physical activity. Measuring REE is essential for estimating total energy expenditure. As such, there are a number of different equations in use to predict REE. In recent years, an increasing number of older adults continue to participate in competitive sports creating the surge of master athletes. It is currently unclear if these equations developed primarily for the general population are also valid for highly active, older master athletes. Therefore, we tested the validity of six commonly-used equations for predicting REE in master athletes. In conjunction with the World Masters Athletic Championship in Malaga, Spain, we measured REE in 113 master athletes by indirect calorimetry. The most commonly used equations to predict REE [Harris &amp; Benedict (H&amp;B), World Health Organization (WHO), Müller (MÜL), Müller-FFM (MÜL-FFM), Cunningham (CUN), and De Lorenzo (LOR)] were tested for their accuracies. The influences of age, sex, height, body weight, FFM, training hours per week, phase angle, ambient temperature, and athletic specialization on REE were determined. All estimated REEs for the general population differed significantly from the measured ones (H&amp;B, WHO, MÜL, MÜL-FFM, CUN, all p &lt; 0.005). The equation put forward by De Lorenzo provided the most accurate prediction of REE for master athletes, closely followed by FFM-based Cunningham’s equation. The accuracy of the remaining commonly-used prediction equations to estimate REE in master athletes are less accurate. Body weight (p &lt; 0.001), FFM (p &lt; 0.001), FM (p = 0.007), sex (p = 0.045) and interestingly temperature (p = 0.004) are the significant predictors of REE. We conclude that REE in master athletes is primarily determined by body composition and ambient temperature. Our study provides a first estimate of energy requirements for master athletes in order to cover adequately athletes’ energy and nutrient requirements to maintain their health status and physical performance.