1,734 research outputs found
The Carnivore Connection Hypothesis: Revisited
The âCarnivore Connectionâ hypothesizes that, during human evolution, a scarcity of dietary carbohydrate in diets with low plantâ:âanimal subsistence ratios led to insulin resistance providing a survival and reproductive advantage with selection of genes for insulin resistance. The selection pressure was relaxed at the beginning of the Agricultural Revolution when large quantities of cereals first entered human diets. The âCarnivore Connectionâ explains the high prevalence of intrinsic insulin resistance and type 2 diabetes in populations that transition rapidly from traditional diets with a low-glycemic load, to high-carbohydrate, high-glycemic index diets that characterize modern diets. Selection pressure has been relaxed longest in European populations, explaining a lower prevalence of insulin resistance and type 2 diabetes, despite recent exposure to famine and food scarcity. Increasing obesity and habitual consumption of high-glycemic-load diets worsens insulin resistance and increases the risk of type 2 diabetes in all populations
International Tables of Glycemic Index and Glycemic Load Values: 2008
OBJECTIVEâTo systematically tabulate published and unpublished sources of reliable glycemic index (GI) values
Effect of the Glycemic Index of Carbohydrates on Acne vulgaris
Acne vulgaris may be improved by dietary factors that increase insulin sensitivity. We hypothesized that a low-glycemic index diet would improve facial acne severity and insulin sensitivity. Fifty-eight adolescent males (mean age ± standard deviation 16.5 ± 1.0 y and body mass index 23.1 ± 3.5 kg/m2) were alternately allocated to high or low glycemic index diets. Severity of inflammatory lesions on the face, insulin sensitivity (homeostasis modeling assessment of insulin resistance), androgens and insulin-like growth factor-1 and its binding proteins were assessed at baseline and at eight weeks, a period corresponding to the school term. Forty-three subjects (n = 23 low glycemic index and n = 20 high glycemic index) completed the study. Diets differed significantly in glycemic index (mean ± standard error of the mean, low glycemic index 51 ± 1 vs. high glycemic index 61 ± 2, p = 0.0002), but not in macronutrient distribution or fiber content. Facial acne improved on both diets (low glycemic index â26 ± 6%, p = 0.0004 and high glycemic index â16 ± 7%, p = 0.01), but differences between diets did not reach significance. Change in insulin sensitivity was not different between diets (low glycemic index 0.2 ± 0.1 and high glycemic index 0.1 ± 0.1, p = 0.60) and did not correlate with change in acne severity (Pearson correlation r = â0.196, p = 0.244). Longer time frames, greater reductions in glycemic load or/and weight loss may be necessary to detect improvements in acne among adolescent boys
The Polarized 3-He Target
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Suppressed radio emission in supercluster galaxies: enhanced ram pressure in merging clusters?
The environmental influence on the 1.4 GHz continuum radio emission of
galaxies is analyzed in a 600 deg2 region of the local Universe containing the
Shapley Supercluster (SSC). Galaxies in the FLASH and 6dFGS redshift surveys
are cross-identified with NVSS radio sources, selected in a subsample doubly
complete in volume and luminosity. Environmental effects are studied through a
smoothed density field (normalized with random catalogs with the same survey
edges and redshift selection function) and the distance to the nearest cluster
(R/r200, where r200 is the virial radius, whose relation to the aperture
velocity dispersion is quantified). The fraction of high radio loudness
(R_K=L_radio/L_K) galaxies in the 10 Mpc Abell 3558 cluster complex at the core
of the SSC (SSC-CR) is half as large than elsewhere. In the SSC-CR, R_K is
anti-correlated with the density of the large-scale environment and correlated
with R/r200: central brightest cluster galaxies (BCGs) in the SSC-CR are 10x
less radio-loud than BCGs elsewhere, with signs of suppressed radio loudness in
the SSC-CR also present beyond the BCGs, out to at least 0.3 r200. This
correlation is nearly as strong as the tight correlation of L_K with R/r200
(K-luminosity segregation), inside the SSC-CR. The suppression of radio
loudness in SSC-CR BCGs can be attributed to cluster-cluster mergers that
destroy the cool core and thus the supply of gas to the central AGN. We
analytically demonstrate that the low radio loudness of non-BCG galaxies within
SSC-CR clusters cannot be explained by direct major galaxy mergers or rapid
galaxy flyby collisions, but by the loss of gas supply through the enhanced ram
pressure felt when these galaxies cross the shock front between the 2 merging
clusters and are later subjected to the stronger wind from the 2nd cluster.Comment: Version consolidated with Erratum A&A 499, 4
The radio and IR counterparts of the ring nebula around HD211564
We report the detection of the radio and infrared counterparts of the ring
nebula around the WN3(h) star HD211564 (WR152), located to the southwest of the
HII region Sh2132. Using radio continuum data from the Canadian Galactic Plane
Survey, we identified the radio counterparts of the two concentric rings, of
about 9' and 16' in radius, related to the star. After applying a filling
factor f = 0.05-0.12, electron densities and ionized masses are in the range
10-16 cm^-3 and 450-700 Mo, respectively. The analysis of the HI gas emission
distribution allowed the identification of 5900 Mo of neutral atomic gas with
velocities between -52 and -43 km/s probably linked to the nebula. The region
of the nebula is almost free of molecular gas. Only four small clumps were
detected, with a total molecular mass of 790 Mo. About 310 Mo are related to a
small infrared shell-like source linked to the inner ring, which is also
detected in the MSX band A. An IRAS YSO candidate is detected in coincidence
with the shell-like IR source.
We suggest that the optical nebula and its neutral counterparts originated
from the stellar winds from the WR star and its massive progenitor, and are
evolving in the envelope of a slowly expanding shell centered at (l,b) = (102
30, -0 50), of about 31 pc in radius. The bubble's energy conversion efficiency
is in agreement with recent numerical analysis and with observational results.Comment: 11 pages, 7 figures, accepted in MNRA
The dynamical Green's function and an exact optical potential for electron-molecule scattering including nuclear dynamics
We derive a rigorous optical potential for electron-molecule scattering
including the effects of nuclear dynamics by extending the common many-body
Green's function approach to optical potentials beyond the fixed-nuclei limit
for molecular targets. Our formalism treats the projectile electron and the
nuclear motion of the target molecule on the same footing whereby the dynamical
optical potential rigorously accounts for the complex many-body nature of the
scattering target. One central result of the present work is that the common
fixed-nuclei optical potential is a valid adiabatic approximation to the
dynamical optical potential even when projectile and nuclear motion are
(nonadiabatically) coupled as long as the scattering energy is well below the
electronic excitation thresholds of the target. For extremely low projectile
velocities, however, when the cross sections are most sensitive to the
scattering potential, we expect the influences of the nuclear dynamics on the
optical potential to become relevant. For these cases, a systematic way to
improve the adiabatic approximation to the dynamical optical potential is
presented that yields non-local operators with respect to the nuclear
coordinates.Comment: 22 pages, no figures, accepted for publ., Phys. Rev.
Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium
We report on a first measurement of tensor analyzing powers in quasi-elastic
electron-deuteron scattering at an average three-momentum transfer of 1.7
fm. Data sensitive to the spin-dependent nucleon density in the deuteron
were obtained for missing momenta up to 150 MeV/ with a tensor polarized
H target internal to an electron storage ring. The data are well described
by a calculation that includes the effects of final-state interaction,
meson-exchange and isobar currents, and leading-order relativistic
contributions.Comment: 4 pages, 3 figure
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