Modelling of maize production in Croatia: present and future climate.

Maize is one of the most important agricultural crops in Croatia, and was selected for research of the effect of climate warming on yields. The Decision Support System for the Agrotechnology Transfer model (DSSAT) is one of the most utilized crop-weather models in the world, and was used in this paper for the investigation of maize growth and production in the present and future climate. The impact of present climate on maize yield was studied using DSSAT 4.0 with meteorological data from the Zagreb-Maksimir station covering the period 1949-2004. Pedological, physiological and genetic data from a 1999 field maize experiment at the same location were added. The location is representative of the continental climate in central Croatia. The linear trends of model outputs and the non-parametric Mann-Kendall test indicate that the beginning of silking has advanced significantly by 1·4 days/decade since the mid-1990s, and maturity by 4·5 days/decade. It also shows a decrease in biomass by 122 kg/ha and in maize yield by 216 kg/ha in 10 years.Estimates of the sensitivity of maize growth and yield in future climates were made by changing the initial weather and CO(2) conditions of the DSSAT 4.0 model according to the different climatic scenarios for Croatia at the end of the 21st century. Changed climate suggests increases in global solar radiation, minimal temperature and maximal temperature (×1·07, 2 and 4°C, respectively), but a decrease in the amount of precipitation (×0·92), compared with weather data from the period 1949-2004. The reduction of maize yield was caused by the increase in minimal and maximal temperature and the decrease in precipitation amount, related to the present climate, is 6, 12 and 3%, respectively. A doubling of CO(2) concentration stimulates leaf assimilation, but maize yield is only 1% higher, while global solar radiation growth by 7% increases evapotranspiration by 3%. Simultaneous application of all these climate changes suggested that the maize growth period would shorten by c. 1 month and maize yield would decrease by 9%, with the main reason for maize yield reduction in Croatia being due to extremely warm conditions in the future climate.

Ultra short-term heart rate recovery after maximal exercise in continuous versus intermittent endurance athletes.

This study tested the hypothesis that athletes participating in intermittent sports would exhibit a faster heart rate recovery (HRR) during the initial phase (<30 s) following maximal exercise than athletes participating in continuous endurance sports. Forty-six male athletes were allocated into continuous (CNT, n = 24) or intermittent groups (INT, n = 22), matched for age and aerobic fitness. Athletes performed maximal exercise on a treadmill using the ramp protocol. Immediately upon exercise cessation, subjects were placed supine with continuous measurement of HR during the first minute of recovery. Data were analyzed in 10-s intervals and compared between the groups. Repeated measures ANOVA showed a group x time interaction effects (p

Validity of the modified Conconi running test.

The aim of this study was to assess the validity of a fast ramp treadmill protocol for determination of the heart rate deflection point (HR (dp)) and speed of deflection (S (dp)) in trained runners. Fifty-one trained male runners performed a standard (T (stand); speed increase 1 km . h (-1) every 60 s) and a fast (T (fast); speed increase 1 km . h (-1) every 30 s) incremental treadmill test until volitional exhaustion. Heart rate was continuously recorded, and the HR (dp) was estimated after data averaging as the point of deflection in the linear speed/HR relationship. The HR (dp) and S (dp) recorded in T (fast) were compared with the corresponding values obtained in T (stand) by examining the Student's T-test, correlation coefficient (r), and limits of agreement (LoA). The HR (dp) recorded during standard and fast treadmill protocol were highly correlated (r = 0.92, p < 0.001) and similar to each other (p = 0.79). In contrast, S (dp) was highly correlated (r = 0.91, p < 0.001), but increased significantly with the faster ramp function (p < 0.001). No evidence of systematic bias was evident in the HR (dp) (95 % LoA of 0.2 +/- 7.3 bpm), while a uniform, systematic bias was evident for S (dp) in the T (fast) (95 % LoA of 1.6 +/- 1.5 km x h (-1)). We conclude that a fast ramp treadmill protocol (speed increase 1 km x h (-1) every 30 s) may be used for determination of the HR (dp) in trained runners, while S (dp) is protocol dependent and caution is warranted regarding its practical applicability.

Can greater muscularity in larger individuals resolve the 3/4 power-law controversy when modelling maximum oxygen uptake?

BACKGROUND: The power function relationship, MR = a.m(b), between metabolic rate (MR) and body mass m has been the source of much controversy amongst biologists for many years. Various studies have reported mass exponents (b) greater than the anticipated 'surface-area' exponent 0.67, often closer to 0.75 originally identified by Kleiber. AIM: The study aimed to provide a biological explanation for these 'inflated' exponents when modelling maximum oxygen uptake (max), based on the observations from this and previous studies that larger individuals develop disproportionately more muscle mass in the arms and legs. RESEARCH DESIGN AND SUBJECTS: A cross-sectional study of 119 professional soccer players from Croatia aged 18-34 was carried out. RESULTS: Here we confirm that the power function relationship between max and body mass of the professional soccer players results in an 'inflated' mass exponent of 0.75 (95% confidence interval from 0.56 to 0.93), but also the larger soccer players have disproportionately greater leg muscle girths. When the analysis was repeated incorporating the calf and thigh muscle girths rather than body mass as predictor variables, the analysis not only explained significantly more of the variance in max, but the sum of the exponents confirmed a surface-area law. CONCLUSIONS: These findings confirm the pitfalls of fitting body-mass power laws and suggest using muscle-girth methodology as a more appropriate way to scale or normalize metabolic variables such as max for individuals of different body sizes.

Evolución de la psicoterapia grupal en la asistencia psiquiátrica: la Batería "Bel-Air" / Group psychotherapy in psychiatric care: the Bel-Air Evaluation Battery

En el presente trabajo se revisa, en primer lugar, la literatura sobre la eficacia global de las psicoterapias de grupo en relación con las individuales y luego se comparan los resultados de las terapias grupales duraderas con las breves y de las de diferentes orientaciones teóricas (dinámica, cognitivo-comportamental y psícoeducativa) entre sí y en pacientes con distintos diagnósticos. Algunos estudios meta-analíticos muestran un "efecto talla" ("effect size") similar al que se puede obtener en los estudios de eficacia de los psicofármacos. Hay algunos trabajos de revisión que afirman que no existen claras ventajas de unas variedades respecto de otras pero otros estudios, en cambio, privilegian ya sea las unas o las otras. Después discutimos el grado de objetividad de las investigaciones en el campo y de los instrumentos que se han utilizado con más frecuencia. Finalizamos describiendo la Batería "Bel-Air" de evaluación que utilizamos en el Departamento de Psiquiatría de la Facultad de Medicina de la Universidad de Ginebra. Consta de tres instrumentos adaptados de otros conocidos en la literatura: Una lista corta de síntomas (The Brief Symptoms Inventory, BSI), La Escala de Funcionamiento Global (GBS), El Cuestionario de Estrategias de Enfrentamiento de ("Coping index" de K. Sherrer y U. Scherrer) y El Cuestionario de Clima Grupal (adaptado de McKezie, 1990). Hemos añadido también dos instrumentos de creación propia. El cuestionario de evaluación de las relaciones con los demás (ERA, Fredenrich & Zinetti, 2000, en prensa) y el Cuestionario de Funciones sociales (QFS). Todos estos instrumentos permiten medir características comunes a grupos de muy diverso tipo en un tiempo corto. En cada grupo específico, se pueden naturalmente añadir otros instrumentos específicos para distintas patologías para otras variables. (AU)