Ability of matrix models to explain the past and predict the future of plant populations.

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models.

How do plant ecologists use matrix population models?

Matrix projection models are among the most widely used tools in plant ecology. However, the way in which plant ecologists use and interpret these models differs from the way in which they are presented in the broader academic literature. In contrast to calls from earlier reviews, most studies of plant populations are based on < 5 matrices and present simple metrics such as deterministic population growth rates. However, plant ecologists also cautioned against literal interpretation of model predictions. Although academic studies have emphasized testing quantitative model predictions, such forecasts are not the way in which plant ecologists find matrix models to be most useful. Improving forecasting ability would necessitate increased model complexity and longer studies. Therefore, in addition to longer term studies with better links to environmental drivers, priorities for research include critically evaluating relative/comparative uses of matrix models and asking how we can use many short-term studies to understand long-term population dynamics.

Effects of intra-set rest on the ability to repeat work at maximal isometric strength.

BACKGROUND: The aim of this paper was to analyze how the rest between interval repetitions in intra-set training (at maximal isometric loads) could affect the ability to repeat maximal contractions in subjects with different levels of performance and different experience in strength development work. METHODS: Twenty subjects were divided randomly into two different groups depending on their sport characteristics: ten subjects were trained in strength development work (Group Strenght--23.1±4.6 years; 172.0±5.3 cm; 79.9±12.1 kg; 2175.6±490.8 N; 46.9±4.9 mL/kg.min), and ten subjects were trained in endurance work (Group Endurance--21.3±4.5 years; 172.4±4.1 cm; 60.0±4.6 kg; 815.5±206.5 N; 67.4±4.9 mL/kg.min). To assess the ability to repeat maximal efforts, 20 repetitions of 5 seconds were performed in a half-squat position, with 1 minute of rest between repetitions. RESULTS: For both groups, four different phases were observed in the Interval Maximal Force test during the 20-repetition assessment: potentiation, maintenance, moderate loss, and significant loss. For the GE, the loss in maximum strength capacity began in the fourth repetition (GS4th: 3.4%, ns, Effect Size: 0.09 vs. GE3th: 1.6%; ns; ES: 0.06) and reached a statistically significant value in the twelfth repetition (GS12th: 12.7%, P=0.03, ES: 0.35 vs. GE7th: 12.5%; P=0.01; ES: 0.49). The number of repetitions at which the strength began to decrease depended on the subject's sport characteristic and performance level. CONCLUSIONS: This study shows how an appropriate intra-set rest inclusion can significantly increase the work performed in every set without changing the muscle contraction characteristics, thus delaying muscle fatigue and maintaining the desired training objective.

Soft Computing Techniques for the Protein Folding Problem on High Performance Computing Architectures.

The protein-folding problem has been extensively studied during the last fifty years. The understanding of the dynamics of global shape of a protein and the influence on its biological function can help us to discover new and more effective drugs to deal with diseases of pharmacological relevance. Different computational approaches have been developed by different researchers in order to foresee the threedimensional arrangement of atoms of proteins from their sequences. However, the computational complexity of this problem makes mandatory the search for new models, novel algorithmic strategies and hardware platforms that provide solutions in a reasonable time frame. We present in this revision work the past and last tendencies regarding protein folding simulations from both perspectives; hardware and software. Of particular interest to us are both the use of inexact solutions to this computationally hard problem as well as which hardware platforms have been used for running this kind of Soft Computing techniques.

Heart health risk assessment system: a nonintrusive proposal using ontologies and expert rules.

According to the World Health Organization, the world's leading cause of death is heart disease, with nearly two million deaths per year. Although some factors are not possible to change, there are some keys that help to prevent heart diseases. One of the most important keys is to keep an active daily life, with moderate exercise. However, deciding what a moderate exercise is or when a slightly abnormal heart rate value is a risk depends on the person and the activity. In this paper we propose a context-aware system that is able to determine the activity the person is performing in an unobtrusive way. Then, we have defined ontology to represent the available knowledge about the person (biometric data, fitness status, medical information, etc.) and her current activity (level of intensity, heart rate recommended for that activity, etc.). With such knowledge, a set of expert rules based on this ontology are involved in a reasoning process to infer levels of alerts or suggestions for the users when the intensity of the activity is detected as dangerous for her health. We show how this approach can be accomplished by using only everyday devices such as a smartphone and a smartwatch.

Last minute in NBA games / Último mínuto en los partidos de la NBA

Apparently the behavior during a basketball game, as in other team sports, shows tremendous variability manifested in both individual and collective ways. However, when a significant number of games are studied, we can observe the unpredictability that characterizes the game. The degree of complexity of the game is not stable. Patterns change during all the game time, but the last minute is completely different reality. Our aim was to test and evaluate the existence of these patterns and their apparent complexity, by analyzing the NBA games scoring and substitution dynamics. Therefore, we examined the difference between the last minute and the rest of the game from the collected scores (1, 2 and 3 points), substitutions and timeouts. The underlying chaotic behavior of nonlinear interactions is inherent in Complex Systems. The data showed the existence of symmetries and repeated patterns of play during basketball games of the NBA but the last minute, which can be considered a completely different game

Aparentemente, el comportamiento del juego durante un partido de baloncesto, igual que en el resto de deportes de equipo, muestra una enorme variabilidad que se manifiesta tanto en las acciones individuales y en las colectivas. No obstante, cuando se estudia una cantidad significativa de partidos se detecta que, dentro de la impredecibilidad que caracteriza al juego, existen, al menos en el baloncesto NBA, patrones de comportamiento repetitivos que, frecuentemente, son libres de escala. El grado de complejidad del juego no es estable. Diferentes investigaciones muestran como los patrones cambian entre el primer y segundo tiempo del partido, así como, primer y tercer cuarto respecto al segundo y cuarto, o la parte inicial, mitad o final de cada cuarto. Nuestro objetivo fue comprobar y evaluar la existencia de estos patrones, y su aparente complejidad, analizando el final de los partidos de la NBA y comparando esta fase del encuentro con el final de cada uno de los cuartos. Los datos muestran la existencia de simetrías (fractalidad) y patrones repetidos de juego durante los partidos de baloncesto de la NBA

Mechanical response of knee muscles in high level bodyboarders during performance / Respostas mecânicas da musculatura do joelho de bodyboarders de alto nível durante o desempenho / Respuesta mecánica de la musculatura de la rodilla en bodyboarders de alto nivel durante el desempeño

INTRODUCTION: bodyboarding is a kind of surfing that has been growing very rapidly over the last decade and has now developed into one of the fastest growing water sports in the world. OBJECTIVES: evaluate the effects of fatigue on rectus femoris RF, vastus lateralis VL and vastus medialis VM and biceps femoris BF and semitendinosus ST during a high-level bodyboard competition using tensiomyography TMG. METHODS: subjects were 11 highly experienced years of practice: 15, SD=4.65 male bodyboarders age: 28.17, SD=2.89, body weight: 74.83, SD=6.13kg; height: 179.25, SD=3.93cm; BMI: 23.29, SD=1.81 participating in the final of the 2010 Spanish championship. RESULTS: the fatigue is especially evident due to a decrease in the values of relaxation time Tr and sustain time Ts caused by the specific characteristics of waves, how the waves evolve and the type of manoeuvre executed in competition due to the wave characteristics. The maximum radial displacement Dm value increased slightly in all muscles analysed and normalised response speed Vrn was stable, with a tendency to improve as athletes adapted to the type of physical effort and the environmental conditions of the competition. CONCLUSIONS: the study shows that the fatigue in the extensor and flexor muscles of the knee occurs in response to the demands of competition. .

INTRODUÇÃO: bodyboarding é uma modalidade do surfe que vem crescendo rapidamente nas últimas décadas e atualmente é um dos esportes aquáticos que mais cresce no mundo. OBJETIVO: avaliar o efeito da fadiga nos músculos reto femoral RF, vasto lateral VL, vasto medial VM, bíceps femoral BF e semitendíneo ST durante competição de alto nível através da tensiomiografia TMG. MÉTODOS: a amostra foi composta por 11 bodyboarders de alto nível anos de prática: 15, DP = 4,65, idade: 28,17, DP = 2,89 anos, peso: 74,83, DP = 6,13 kg; estatura: 179,25, DP = 3,93 cm; IMC: 23,29, DP = 1,81, participantes da final do Campeonato Espanhol de 2010. RESULTADOS: a fadiga é evidente devido a uma diminuição dos valores de tempo de relaxamento Tr e tempo de sustentação Ts, que pode ser causada pelas características das ondas, de como elas se comportam e ao tipo de manobras realizadas em competição. Os valores de deslocamento radial máximo Dm aumentaram em todos os músculos analisados e a velocidade de resposta normalizada foi estável, com uma leve tendência à melhora conforme os atletas se adaptam ao tipo de esforço físico e às condições ambientais da competição. CONCLUSÃO: observou-se fadiga da musculatura flexora e extensora do joelho em repostas às demandas da competição. .

INTRODUCCIÓN: el bodyboard es una modalidad del surf que viene creciendo rápidamente en las últimas décadas y actualmente es uno de los deportes acuáticos que más crece en el mundo. OBJETIVOS: evaluar los efectos de la fatiga en los músculos: recto femoral RF, vasto lateral VL, vasto medial VM, bíceps femoral BF y semitendinoso ST durante una competición de alto nivel mediante la tensiomiografia TMG. MÉTODOS: la muestra estaba compuesta por 11 bodyboarders de alto nivel años de práctica: 15, DE = 4,65, edad: 28,17, DE = 2,89, peso: 74.83, DE = 6,13 kg; altura: 179,25, DE = 3,93 cm; IMC: 23,29, DE = 1,81, participantes en la final del Campeonato de España de 2010. RESULTADOS: la fatiga es evidente debido a una disminución de los valores del tiempo de relajación Tr y tiempo de sustentación Ts, que puede ser causada por las características de las olas, de como éstas se comportan y al tipo de maniobras realizadas durante la competición. Los valores de desplazamiento máximo radial Dm aumentaron en todos los músculos analizados y la velocidad de respuesta normalizada Vrn se muestra estable, con tendencia a mejorar, debido a la adaptación de los deportistas al tipo de esfuerzo y a las condiciones ambientales en que se desarrolla la competición. CONCLUSIÓN: el estudio muestra que la fatiga en los músculos extensores y flexores de la rodilla se produce en respuesta a las exigencias propias de la competición. .