Fatty acid composition of plasma lipids in healthy Portuguese children: Is the Mediterranean diet disappearing?

Background: Adults and children in Mediterranean countries are believed to consume a Mediterranean-type diet wh ich is h ig her in monounsaturated a nd n-3 polyunsaturated fatty acids than compared to central and northern parts of Europe and has preventive effects for cardiovascular risks. Subjects and Methods: in preschool children from Porto, Portugal (n = 35) and Munich, Germany (n = 18) we determined the plasma phospholipid fatty acid composition considered as a biomarker for dietary fat intake. Results: The plasma phospholipid contents of total saturated fatty acids are similar in both groups, but the Portuguese children have lower values of monounsaturated and n-3 polyunsaturated fatty acids. The results indicate that the food habits of Portuguese children are even less close to the traditional Mediterranean diet than those of German children, Conclusions: Efforts should be made to encourage young families as well as manufacturers and distributors of food products in Portugal to emphasize traditional Mediterranean food habits, especially in young children. Copyright (C) 2001 S. Karger AG. Basel

Characterizing the Hadley circulation response through regional climate feedbacks

The robust weakening of the tropical atmospheric circulation in projections of anthropogenic warming is associated with substantial changes in regional and global climate. The present study focuses on understanding the response of the annual-mean Hadley circulation from a perspective of interactions between climate feedbacks and tropical circulation. Simulations from an ensemble of coupled ocean–atmosphere models are used to quantify changes in Hadley cell strength in terms of feedbacks, radiative forcing, ocean heat uptake, atmospheric eddies, and gross moist stability. Climate feedbacks are calculated for the model integrations from phase 5 of CMIP (CMIP5) using radiative kernels. Tropical mean circulation is found to be reduced by up to 2.6% K^(−1) for an abrupt quadrupling of carbon dioxide concentration. The weakening is characterized by an increase in gross moist stability, by an increase in eddy heat flux, and by positive extratropical feedbacks, such as those associated with lapse rate and sea ice response. Understanding the impact of radiative feedbacks on the large-scale circulation provides a framework for constraining uncertainty in the dynamic climate response, including the hydrological cycle

Coupled High-Latitude Climate Feedbacks and Their Impact on Atmospheric Heat Transport

The response of atmospheric heat transport to anthropogenic warming is determined by the anomalous meridional energy gradient. Feedback analysis offers a characterization of that gradient and hence reveals how uncertainty in physical processes may translate into uncertainty in the circulation response. However, individual feedbacks do not act in isolation. Anomalies associated with one feedback may be compensated by another, as is the case for the positive water vapor and negative lapse rate feedbacks in the tropics. Here a set of idealized experiments are performed in an aquaplanet model to evaluate the coupling between the surface albedo feedback and other feedbacks, including the impact on atmospheric heat transport. In the tropics, the dynamical response manifests as changes in the intensity and structure of the overturning Hadley circulation. Only half of the range of Hadley cell weakening exhibited in these experiments is found to be attributable to imposed, systematic variations in the surface albedo feedback. Changes in extratropical clouds that accompany the albedo changes explain the remaining spread. The feedback-driven circulation changes are compensated by eddy energy flux changes, which reduce the overall spread among experiments. These findings have implications for the efficiency with which the climate system, including tropical circulation and the hydrological cycle, adjusts to high-latitude feedbacks over climate states that range from perennial or seasonal ice to ice-free conditions in the Arctic

The influence of regional feedbacks on circulation sensitivity

Weakening of the tropical overturning circulation in a warmer world is a robust feature in climate models. Here an idealized representation of ocean heat flux drives a Walker cell in an aquaplanet simulation. A goal of the study is to assess the influence of the Walker circulation on the magnitude and structure of climate feedbacks, as well as to global sensitivity. We compare two CO_2 perturbation experiments, one with and one without a Walker circulation, to isolate the differences attributable to tropical circulation and associated zonal asymmetries. For an imposed Walker circulation, the subtropical shortwave cloud feedback is reduced, which manifests as a weaker tropical-subtropical anomalous energy gradient and consequently a weaker slow down of the Hadley circulation, relative to the case without a Walker circulation. By focusing on the coupled feedback circulation system, these results offer insights into understanding changes in atmospheric circulation and hence the hydrological cycle under global warming

Differences in Water Vapor Radiative Transfer among 1D Models Can Significantly Affect the Inner Edge of the Habitable Zone

An accurate estimate of the inner edge of the habitable zone is critical for determining which exoplanets are potentially habitable and for designing future telescopes to observe them. Here, we explore differences in estimating the inner edge among seven one-dimensional radiative transfer models: two line-by-line codes (SMART and LBLRTM) as well as five band codes (CAM3, CAM4_Wolf, LMDG, SBDART, and AM2) that are currently being used in global climate models. We compare radiative fluxes and spectra in clear-sky conditions around G and M stars, with fixed moist adiabatic profiles for surface temperatures from 250 to 360 K. We find that divergences among the models arise mainly from large uncertainties in water vapor absorption in the window region (10 μm) and in the region between 0.2 and 1.5 μm. Differences in outgoing longwave radiation increase with surface temperature and reach 10–20 W m^(−2); differences in shortwave reach up to 60 W m^(−2), especially at the surface and in the troposphere, and are larger for an M-dwarf spectrum than a solar spectrum. Differences between the two line-by-line models are significant, although smaller than among the band models. Our results imply that the uncertainty in estimating the insolation threshold of the inner edge (the runaway greenhouse limit) due only to clear-sky radiative transfer is ≈10% of modern Earth's solar constant (i.e., ≈34 W m^(−2) in global mean) among band models and ≈3% between the two line-by-line models. These comparisons show that future work is needed that focuses on improving water vapor absorption coefficients in both shortwave and longwave, as well as on increasing the resolution of stellar spectra in broadband models

Fold and thrust partitioning in a contracting fold belt: Insights from the 1931 Mach earthquake in Baluchistan

Surface deformation associated with the 27 August 1931 earthquake near Mach in Baluchistan is quantified from spirit-leveling data and from detailed structural sections of the region interpreted from seismic reflection data constrained by numerous well logs. Mean slip on the west dipping Dezghat/Bannh fault system amounted to 1.2 m on a 42 km x 72 km thrust plane with slip locally attaining 3.2 m up dip of an inferred locking line at approximately 9 km depth. Slip also occurred at depths below the interseismic locking line. In contrast, negligible slip occurred in the 4 km near the interseismic locking line. The absence of slip here in the 4 years following the earthquake suggests that elastic energy there must either dissipate slowly in the interseismic cycle, or that a slip deficit remains, pending its release in a large future earthquake. Elastic models of the earthquake cycle in this fold and thrust belt suggest that slip on the frontal thrust fault is reduced by a factor of 2 to 8 compared to that anticipated from convergence of the hinterland, a partitioning process that is presumably responsible for thickening of the fold and thrust belt at the expense of slip on the frontal thrust. Near the latitude of Quetta, GPS measurements indicate that convergence is approximately 5 mm/yr. Hence the minimum renewal time between earthquakes with 1.2-m mean displacement should be as little as 240 years. However, when the partitioning of fold belt convergence to frontal thrust slip is taken into account the minimum renewal time may exceed 2000 years

Fatty acid composition of plasma lipids in healthy Portuguese children: Is the Mediterranean diet disappearing?

Background: Adults and children in Mediterranean countries are believed to consume a Mediterranean-type diet wh ich is h ig her in monounsaturated a nd n-3 polyunsaturated fatty acids than compared to central and northern parts of Europe and has preventive effects for cardiovascular risks. Subjects and Methods: in preschool children from Porto, Portugal (n = 35) and Munich, Germany (n = 18) we determined the plasma phospholipid fatty acid composition considered as a biomarker for dietary fat intake. Results: The plasma phospholipid contents of total saturated fatty acids are similar in both groups, but the Portuguese children have lower values of monounsaturated and n-3 polyunsaturated fatty acids. The results indicate that the food habits of Portuguese children are even less close to the traditional Mediterranean diet than those of German children, Conclusions: Efforts should be made to encourage young families as well as manufacturers and distributors of food products in Portugal to emphasize traditional Mediterranean food habits, especially in young children. Copyright (C) 2001 S. Karger AG. Basel

Magnetic characteristics of epitaxial NiO films studied by Raman spectroscopy

Raman spectroscopy is utilized to study the magnetic characteristics of heteroepitaxial NiO thin films grown by plasma-assisted molecular beam epitaxy on MgO(100) substrates. For the determination of the N\'eel temperature, we demonstrate a reliable approach by analyzing the temperature dependence of the Raman peak originating from second-order scattering by magnons. The antiferromagnetic coupling strength is found to be strongly influenced by the growth conditions. The low-temperature magnon frequency and the N\'eel temperature are demonstrated to depend on the biaxial lattice strain and the degree of structural disorder which is dominated by point defects