Análisis secuencial de golpeos finales del punto en pádel mediante árbol decisional / Analysis of Shots Patterns Finishing the Point in Padel through Decision-Tree Analysis

El objetivo de este estudio fue analizar la secuencia de los dos últimos golpeos del punto en pádel, y clasificarlos a través de árbol decisional multivariante. Se analizaron un total de 2110 acciones de juego, siendo las variables analizadas: golpeo, zona de la pista, eficacia, dirección, resultado y lado de juego. Los partidos fueron analizados mediante observación sistemática. Los resultados mostraron que mantener posiciones cercanas a la red aumenta las probabilidades de victoria, observándose que las secuencias de finalización más frecuentes son las de fondo-volea y globo-remate. Las parejas ganadoras realizan mayor número de puntos ganadores en la red y menos errores en el fondo de la pista. Además, utilizar trayectorias cruzadas en el penúltimo golpe aumentará las posibilidades de un error posterior de los rivales. Estos datos tienen aplicación práctica en el entrenamiento perceptivo y decisional del jugador de pádel, y la aplicación de feedbacks por parte del entrenador. (AU)

The main objective was to analyze the sequence of the last two shots of the point in padel and to make a classification through the multivariate decision tree approach. A total of 2110 game actions were analyzed. The variables analyzed were: shot, court zone, efficiency, direction, match outcome and side court. Matches were analyzed through systematic observation. The results determined that maintain net positions during the last two shots would increase the probabilities of victory, observing that the most frequent sequence of the last two shots were groundstroke-volley and lob-smash. In addition, winners make the highest number of winning points on the net and the least number of errors at the baseline. On the other hand, the use of cross-court shots will increase the chances of a opponents’ error. These data have an important practical application in the perceptive and decisional training and the feedback application by the coach. (AU)

The complex relationship between effort and heart rate: a hint from dynamic analysis.

OBJECTIVE: Dynamic analysis can be used to study the changes of self-regulated biological processes driven by external stimuli. Recently, the changes of heart rate during effort tests has successfully been adjusted using a simple first-order differential equation model driven by body power expenditure. Although this approach produces valid estimates and yields pertinent indices for the analysis of such measurements, it suffers from an inability to model the saturation of the heart-rate increase at high power expenditures and the change of heart-rate equilibrium following effort. APPROACH: We propose a new analysis allowing the estimation of changes of the heart rate in response to effort (gain) as a function of the power expenditure value. MAIN RESULTS: When applied to the measured heart rates of 30 amateur athletes performing a maximum graded-effort treadmill test, the proposed model was able to predict 99% of the heart rate change measured during exercise. The estimated gains decreased with a power increase above the first ventilatory threshold. This trend was stronger above the second ventilatory threshold and was strongly correlated with the maximum oxygen consumption. SIGNIFICANCE: The proposed approach yields a highly precise model of heart rate dynamics during variable effort that reflects the changes of metabolic energy systems at play during exercise.

Cost effectiveness and quality of life in knee arthroplasty.

Few studies quantitate the cost of a quality well being as produced by arthroplasty surgery. The objective was to use the Quality of Well Being Index to calculate the cost per quality of well year in knee arthroplasty surgery. The difference in Quality of Well Being Index scores before and after the intervention was calculated and multiplied by the patient's life expectancy. The procedure cost was divided by this quantity resulting in the cost of a quality well year. One hundred patients underwent a primary knee arthroplasty. There were 30 males (average age, 62 years old) and 70 females (average age, 64 years old). The calculated costs per a quality well year were $30,695 (standard deviation $90,883) at 3 months, $17,804 (standard deviation $25,888) at 6 months, $11,560 (standard deviation $11,874) at 1 year, and $6656 (standard deviation $3567) at 2 years postsurgery. Health economists consider an intervention costing less than $30,000 per quality of well year a bargain to society. Cost effectiveness of knee arthroplasty surgery compares favorably with other surgical interventions such as coronary artery bypass surgery ($5000 per quality of well year) and extremely favorable with medical treatments such as renal dialysis ($50,000.00 for the quality well year). Knee arthroplasty is a cost effective procedure and should be considered an appropriate investment by society.

Relationship of surgical volume to short-term mortality, morbidity, and hospital charges in arthroplasty.

In 1992, the Agency of Health Care Administration in Tallahassee, Florida, started releasing, as part of the patient discharge information, the names of the treating physicians, in addition to demographic and diagnostic data. This information is available to the general public for a small price and is being used by health planners, hospital administrators, finance departments, third-party payers, and other agencies involved in health care. Patient discharge information was used to assess the effects of volume on the short-term outcome of primary and revision hip and knee arthroplasty as a function of surgeon and hospital in the State of Florida, during 1992. A total of 19,925 primary and 2,536 revision arthroplasties of the hip and knee were performed during 1992 in Florida and were available for study. After the doctors and hospitals were arbitrarily divided into three case volume groups (low, medium, high), results showed that in primary arthroplasty, surgeons with a low volume of primary cases (< 10) have a significantly higher mortality rate (24%), higher average charges ($25,000), and increased average length of hospital stay (9.3 days). In revision surgery, physicians with a low volume of cases (< 10) have a higher mortality rate (13%) and increased average length of hospital stay (9.8 days). Patients discharge information has many potential uses for investigators interested in the short-term outcome of arthroplasty. In their present form, these databases should not be released to the general public or the media. Lastly, the volume-outcome relation for a specific surgical procedure should, in addition to case severity, account for characteristics affecting the degree of technical difficulty.

A nuclear magnetic resonance spectroscopic and conformational study of eight pseudo-trehaloses (D-glucopyranosyl 5a-carba-D- and -L-glucopyranosides).

N.m.r. data (1H and 13C) are presented for eight pseudo-trehalose derivatives in which the D-glucopyranosyl moiety is alpha or beta and the 5a-carbaglucopyranoside moiety is alpha-D, beta-D, alpha-L, or beta-L. The differences in the chemical shifts and then n.O.e. effects have been correlated with the preferred conformations estimated from empirical force-field calculations (HSEA), which have been used to calculate the average parameters over the whole energy surface. Of the four alpha-D-glucopyranosyl derivatives, only that with a 5a-carba-beta-D-glucopyranoside moiety (3) was a substrate for glucoamylase.

[Acute respiratory insufficiency in polyneuritis]. / Insuficiencia respiratoria grave en polineuritis.

Lethality in polineuritis is directly related to severe respiratory distress. The latter dropped from 40 to 0% in severe types at Hospital de Pediatría del Centro Médico Nacional with the procedures of assistance to the positive pressure ventilation and tracheostomy. The application of pressure is offered to be given at the end of expiration to correct hypoxemia from short circuit due to decrease in V/Q relation PEEP in, Retrospective study of 13 cases.