Insulin secretion response during oral glucose tolerance test is related to low cardiorespiratory fitness in obese adolescents

Background: The obesity paradox refers to a category of subjects who may be less prone to develop co-morbidities, such as type 2 diabetes. Cardiorespiratory fitness (CRF) has been identified as one of the key factors. We aimed at exploring the difference in insulin metabolism between fit and unfit obese adolescents. Methods: We recruited 22 obese adolescents and assessed CRF during an incremental treadmill test. According to a cut-off at 80% of predicted maximal oxygen consumption (VO2max), subjects were separated into low or normal CRF. Body composition was determined by densitometry. Serum levels of insulin were measured sequentially during an oral glucose tolerance test and insulin secretion responses were calculated. Results: Compared to adolescents with normal CRF, the ones with low CRF had higher insulin resistance indices (p=0.023) and insulin secretion response (p=0.010), independently of the body mass index z-score. Conclusions: Interventions in obese adolescents should focus on the maintenance or improvement of CRF to at least 80% of predicted VO2max. Indeed, this cut-off was significantly related to insulin secretion responses, independently of the adiposity level. A CRF above the proposed cut-off may prevent the development of insulin resistance

Aulamar: Projecte escola d’oceanografia costanera

En aquest Research Café es presenten projectes on la tecnologia es posa al servei dels mars i els oceans, i que estan lligats amb els objectius ODS Vida Submarina i Acció pel clima.Objectius de Desenvolupament Sostenible::13 - Acció per al ClimaObjectius de Desenvolupament Sostenible::14 - Vida Submarin

Variations in hydrological connectivity of Australian semiarid landscapes indicate abrupt changes in rainfall-use efficiency of vegetation

[1] Dryland vegetation frequently shows self‐organized spatial patterns as mosaic‐like structures of sources (bare areas) and sinks (vegetation patches) of water runoff and sediments with variable interconnection. Good examples are banded landscapes displayed by Mulga in semiarid Australia, where the spatial organization of vegetation optimizes the redistribution and use of water (and other scarce resources) at the landscape scale. Disturbances can disrupt the spatial distribution of vegetation causing a substantial loss of water by increasing landscape hydrological connectivity and consequently, affecting ecosystem function (e.g., decreasing the rainfall‐use efficiency of the landscape). We analyze (i) connectivity trends obtained from coupled analysis of remotely sensed vegetation patterns and terrain elevations in several Mulga landscapes subjected to different levels of disturbance, and (ii) the rainfall‐use efficiency of these landscapes, exploring the relationship between rainfall and remotely sensed Normalized Difference Vegetation Index. Our analyses indicate that small reductions in the fractional cover of vegetation near a particular threshold can cause abrupt changes in ecosystem function, driven by large nonlinear increases in the length of the connected flowpaths. In addition, simulations with simple vegetation‐thinning algorithms show that these nonlinear changes are especially sensitive to the type of disturbance, suggesting that the amount of alterations that an ecosystem can absorb and still remain functional largely depends on disturbance type. In fact, selective thinning of the vegetation patches from their edges can cause a higher impact on the landscape hydrological connectivity than spatially random disturbances. These results highlight surface connectivity patterns as practical indicators for monitoring landscape health

Collection and storage of runoff from hillslopes in a semi-arid environment: geomorphic and hydrologic aspects of the aljibe system in Almeria Province, Spain

Water harvesting systems in south-east Spain collect runoff from hillslopes in underground cisterns (aljibes). The characteristics of 51 aljibes were recorded. Aljibe volume increases non-linearly with catchment area (r(2) = 0.29; N = 51). This relationship becomes even stronger for the water harvesting systems on rocky slopes (r(2) = 0.56; N = 34). An empirical rainfall/runoff model indicates that the surface characteristics of the catchments are critical in producing sufficient runoff during years with low annual rainfall. The aljibe system is still viable provided the runoff coefficient of the catchments is high (curve number > 90) and the volume of the aljibes is large enough to prevent overflow (volume to catchment area ratio > 60 m(3) ha(-1)). (C) 1998 Academic Press.status: publishe

The XIOM: 20 years of a regional coastal observatory in the Spanish Catalan coast

The importance of coasts and the need for improving knowledge of their environment through the observation and modelling of processes is evident from human activities and ecosystems that they support. This paper presents the coastal observatory in the Spanish Catalan coast and its contribution to a better understanding of processes that take place in this area. The XIOM network for oceanographic and coastal meteorological measurements (Xarxa d'Instrumentacio Oceanografica I Meteorologica) is owned by the Catalan regional government. XIOM buoys collect wave height data at local receiving stations, which is then validated statistically, and the subsequent results are displayed on the website. Water level recordings are based on pressure measurements and atmospheric variables recorded with typical meteorological stations. At present, there is not a continuous measurement of currents or temperatures in the Catalan shelf-slope region, but several moorings have been deployed in the area. The coastal wind field is highly heterogeneous with main components from E, NW and S. This will have some implication for the coastal wind waves. Even with the relatively short fetch in the NW Mediterranean, the Catalan coast can be impacted by damaging waves during storms. At the Ebro delta the complex winds develop bimodal spectral wave features. In the central and north coast typical unimodal spectra are found. The most important variations in sea level in the Catalan coast are due to meteorological conditions and in some areas the resonant effect of bays and harbours. Storm surges may be of the order of 1 m, a magnitude much larger than tidal range. This sea level variation has a very important effect on storm risk and coastal flooding and it is a very important factor when modelling coastal dynamics in extreme events. The continental shelf slope dynamics are dominated by a quasi-permanent slope current. The mean current intensity is not very strong (similar to 10 cm/s at 100 m depth) but it presents a seasonal intensification in winter where velocities can reach higher values. Over the shelf, little work has been previously done over long time series. The measurements obtained allowed the identification of the relative influence of winds, Ebro river outflow and open sea dynamics on the shelf dynamics. An oil spill drift forecasting system has also been developed in which measurements will be used for the short forecast of oil transport. The XIOM is still growing and in a short term period meteorological buoys with current meters will be deployed and scalar buoys will be replaced by directional ones. (C) 2008 Elsevier B.V. All rights reserved