Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Area-level socioeconomic characteristics and incidence of metabolic syndrome: a prospective cohort study

BACKGROUND The evidence linking socioeconomic environments and metabolic syndrome (MetS) has primarily been based on cross-sectional studies. This study prospectively examined the relationships between area-level socioeconomic position (SEP) and the incidence of MetS. METHODS A prospective cohort study design was employed involving 1,877 men and women aged 18+ living in metropolitan Adelaide, Australia, all free of MetS at baseline. Area-level SEP measures, derived from Census data, included proportion of residents completing a university education, and median household weekly income. MetS, defined according to International Diabetes Federation, was ascertained after an average of 3.6 years follow up. Associations between each area-level SEP measure and incident MetS were examined by Poisson regression Generalised Estimating Equations models. Interaction between area- and individual-level SEP variables was also tested. RESULTS A total of 156 men (18.7%) and 153 women (13.1%) developed MetS. Each percentage increase in the proportion of residents with a university education corresponded to a 2% lower risk of developing MetS (age and sex-adjusted incidence risk ratio (RR) = 0.98; 95% confidence interval (CI) =0.97-0.99). This association persisted after adjustment for individual-level income, education, and health behaviours. There was no significant association between area-level income and incident MetS overall. For the high income participants, however, a one standard deviation increase in median household weekly income was associated with a 29% higher risk of developing MetS (Adjusted RR = 1.29; 95%CI = 1.04-1.60). CONCLUSIONS While area-level education was independently and inversely associated with the risk of developing MetS, the association between area-level income and the MetS incidence was modified by individual-level income.Anh D Ngo, Catherine Paquet, Natasha J Howard, Neil T Coffee, Robert Adams, Anne Taylor and Mark Danie

La tríada de la atleta: un fenómeno metabólico

The Female Athlete Triad (Triad) is a syndrome in which low energy availability triggers a broad range of endocrine mechanisms that conserve energy expenditure, and thereby impairs reproductive and skeletal health.  Energy availability is the amount of dietary energy remaining after exercise training for all other physiological functions each day.  The specific kind of reproductive dysfunctions caused by low energy availability are functional hypothalamic menstrual disorders.  To ensure that affected athletes receive appropriate care, endocrine tests are required to diagnose these disorders by the exclusion of other types of menstrual disorders unrelated to the Triad.  In addition, low energy availability impairs skeletal health by uncoupling bone turnover, in which the rate of bone resorption increases while the rate of bone formation declines.  The result is a progressive loss or failure to accrue bone mass, which increases the risks of stress fractures and osteoporosis.  Low energy availability originates in one or more of three sources:  restrictive eating disorders, especially anorexia nervosa; intentional efforts to lose body weight or body fat to improve athletic performance or appearance; and the inadvertent suppression of appetite by exercise and diets containing a high percentage of carbohydrates.  It is necessary to know the origin of low energy availability in a particular athlete in order to intervene effectively with her.  The key behavior modification for preventing and treating the Triad is to increase energy availability, either by increasing dietary energy intake, reducing exercise energy expenditure, or both.  Guidelines for doing so are provided.La tríada de la atleta (tríada) es un síndrome en el cual la baja disponibilidad de energía dispara una amplia gama de mecanismos endocrinos para disminuir el gasto energético, lo cual perjudica la salud reproductiva y esquelética. La disponibilidad energética es la cantidad de energía de la dieta que queda cada día, después del entrenamiento o el ejercicio, para todas las demás funciones fisiológicas. El tipo específico de mal funcionamiento reproductivo provocado por la baja disponibilidad energética son los trastornos menstruales hipotalámicos. Para asegurarse de que las atletas afectadas reciban la atención apropiada es necesario realizar pruebas endocrinas que sirven para diagnosticar los trastornos mencionados mediante la exclusión de otros trastornos menstruales no asociados con la tríada. La baja disponibilidad energética perjudica la salud esquelética debido al desacoplamiento del recambio óseo, en el cual la tasa de resorción aumenta mientras la tasa de formación de hueso desciende. El resultado es una pérdida progresiva de hueso o la incapacidad de acumular masa ósea, lo cual aumenta el riesgo de fracturas por estrés y de osteoporosis. La baja disponibilidad energética tiene su origen en al menos una de las siguientes tres fuentes: trastornos de la alimentación de tipo restrictivo, especialmente la anorexia nerviosa; los esfuerzos intencionales orientados a la pérdida de peso corporal o grasa corporal, para mejorar el rendimiento deportivo o la apariencia; y la supresión inadvertida del apetito causada por el ejercicio y por las dietas con un alto porcentaje de carbohidratos. Para poder realizar una intervención eficaz con cada atleta es necesario conocer el origen de su baja disponibilidad energética. La modificación clave de la conducta para la prevención y tratamiento de la tríada es el aumento de la disponibilidad energética, ya sea mediante el incremento de la ingesta energética en la dieta, la reducción en el gasto energético por ejercicio, o ambos. Por lo tanto, se ofrecen algunas pautas para lograr la disponibilidad energética correcta

Physical health of the female athlete: observations, effects, and causes of reproductive disorders

Proceedings of the 1st International Meeting of the congress on nutrition and athletic performance, Edmonton, Alberta, Canada, August 8-11, 2001 - Communication lors du congrès 'Nutrition et performance sportive', Edmonton, 8-11 aout 1551

Physical health of the female athlete: observations, effects, and causes of reproductive disorders

Proceedings of the 1st International Meeting of the congress on nutrition and athletic performance, Edmonton, Alberta, Canada, August 8-11, 2001 - Communication lors du congrès 'Nutrition et performance sportive', Edmonton, 8-11 aout 1551

La tríada de la atleta: un fenómeno metabólico

The Female Athlete Triad (Triad) is a syndrome in which low energy availability triggers a broad range of endocrine mechanisms that conserve energy expenditure, and thereby impairs reproductive and skeletal health.  Energy availability is the amount of dietary energy remaining after exercise training for all other physiological functions each day.  The specific kind of reproductive dysfunctions caused by low energy availability are functional hypothalamic menstrual disorders.  To ensure that affected athletes receive appropriate care, endocrine tests are required to diagnose these disorders by the exclusion of other types of menstrual disorders unrelated to the Triad.  In addition, low energy availability impairs skeletal health by uncoupling bone turnover, in which the rate of bone resorption increases while the rate of bone formation declines.  The result is a progressive loss or failure to accrue bone mass, which increases the risks of stress fractures and osteoporosis.  Low energy availability originates in one or more of three sources:  restrictive eating disorders, especially anorexia nervosa; intentional efforts to lose body weight or body fat to improve athletic performance or appearance; and the inadvertent suppression of appetite by exercise and diets containing a high percentage of carbohydrates.  It is necessary to know the origin of low energy availability in a particular athlete in order to intervene effectively with her.  The key behavior modification for preventing and treating the Triad is to increase energy availability, either by increasing dietary energy intake, reducing exercise energy expenditure, or both.  Guidelines for doing so are provided.La tríada de la atleta (tríada) es un síndrome en el cual la baja disponibilidad de energía dispara una amplia gama de mecanismos endocrinos para disminuir el gasto energético, lo cual perjudica la salud reproductiva y esquelética. La disponibilidad energética es la cantidad de energía de la dieta que queda cada día, después del entrenamiento o el ejercicio, para todas las demás funciones fisiológicas. El tipo específico de mal funcionamiento reproductivo provocado por la baja disponibilidad energética son los trastornos menstruales hipotalámicos. Para asegurarse de que las atletas afectadas reciban la atención apropiada es necesario realizar pruebas endocrinas que sirven para diagnosticar los trastornos mencionados mediante la exclusión de otros trastornos menstruales no asociados con la tríada. La baja disponibilidad energética perjudica la salud esquelética debido al desacoplamiento del recambio óseo, en el cual la tasa de resorción aumenta mientras la tasa de formación de hueso desciende. El resultado es una pérdida progresiva de hueso o la incapacidad de acumular masa ósea, lo cual aumenta el riesgo de fracturas por estrés y de osteoporosis. La baja disponibilidad energética tiene su origen en al menos una de las siguientes tres fuentes: trastornos de la alimentación de tipo restrictivo, especialmente la anorexia nerviosa; los esfuerzos intencionales orientados a la pérdida de peso corporal o grasa corporal, para mejorar el rendimiento deportivo o la apariencia; y la supresión inadvertida del apetito causada por el ejercicio y por las dietas con un alto porcentaje de carbohidratos. Para poder realizar una intervención eficaz con cada atleta es necesario conocer el origen de su baja disponibilidad energética. La modificación clave de la conducta para la prevención y tratamiento de la tríada es el aumento de la disponibilidad energética, ya sea mediante el incremento de la ingesta energética en la dieta, la reducción en el gasto energético por ejercicio, o ambos. Por lo tanto, se ofrecen algunas pautas para lograr la disponibilidad energética correcta

The response of luteinizing hormone pulsatility to 5 days of low energy availability disappears by 14 years of gynecological age

Context: The incidence of menstrual disorders declines during adolescence. The mechanism responsible is unknown. Objective: The objective of the study was to test the hypothesis, formulated a priori, that the dependence of LH pulsatility and ovarian function on energy availability declines with gynecological age (years since menarche). Design: The study was a controlled experiment repeated in two menstrual cycles, performed 2001-2004. Setting: The study was conducted at a university laboratory and general clinical research center. Participants: The study population consisted of healthy, habitually sedentary, young women of normal body composition with 5-8 yr (adolescents, n =3D 9) and 14-18 yr (adults, n =3D 10) of gynecological age recruited by advertisement from approximately 9000 women aged 18-34 yr in a college community. Samples were similar in age of menarche, length of menstrual cycle and luteal phase, body size and composition, aerobic capacity, and dietary intake. None were withdrawn due to adverse effects. Interventions: Interventions included energy availabilities of 45 and 10 kcal/kg of fat-free mass per day for 5 d in the early follicular phases of separate menstrual cycles in random order. Main Outcome Measures: LH pulsatility, estradiol, and luteal phase length were measured. Results: Low energy availability reduced LH pulse frequency in adolescents (P < 0.01) but not adults (P =3D 0.39), did not increase LH pulse amplitude in either group (both P =3D 0.13), and suppressed 24-h mean LH in adolescents (P =3D 0.01) but not adults (P =3D 0.72). Estradiol was unaffected (both P =3D 0.48), but the subsequent luteal phase was shorter in adolescents (P < 0.01). Conclusions: In women of normal body composition, the response of LH pulsatility and ovarian function to 5 d of low energy availability disappears by 14 yr of gynecological age