2,272 research outputs found
Signatures of inflow motion in cores of massive star formation: Potential collapse candidates
Using the IRAM 30 m telescope, a mapping survey in optically thick and thin
lines was performed towards 46 high mass star-forming regions. The sample
includes UC H{\sc ii} precursors and UC H{\sc ii} regions. Seventeen sources
are found to show "blue profiles", the expected signature of collapsing cores.
The excess of sources with blue over red profiles ([ -- ]/) is 29% in the HCO =1--0 line, with a probability
of 0.6% that this is caused by random fluctuations. UC H{\sc ii} regions show a
higher excess (58%) than UC H{\sc ii} precursors (17%), indicating that
material is still accreted after the onset of the UC H{\sc ii} phase. Similar
differences in the excess of blue profiles as a function of evolutionary state
are not observed in low mass star-forming regions. Thus, if confirmed for high
mass star-forming sites, this would point at a fundamental difference between
low- and high-mass star formation. Possible explanations are inadequate
thermalization, stronger influence of outflows in massive early cores, larger
gas reserves around massive stellar objects or different trigger mechanisms
between low- and high- mass star formation
The Carnivore Connection Hypothesis: Revisited
The “Carnivore Connection” hypothesizes that, during human evolution, a scarcity of dietary carbohydrate in diets with low plant : animal 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 “Carnivore Connection” 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
A systematic review and meta-analysis of energy intake and weight gain in pregnancy
BACKGROUND: Gestational weight gain within the recommended range produces optimal pregnancy outcomes, yet many women exceed the guidelines. Official recommendations to increase energy intake by ∼ 1000 kJ/day in pregnancy may be excessive. OBJECTIVE: To determine by metaanalysis of relevant studies whether greater increments in energy intake from early to late pregnancy corresponded to greater or excessive gestational weight gain. DATA SOURCES: We systematically searched electronic databases for observational and intervention studies published from 1990 to the present. The databases included Ovid Medline, Cochrane Library, Excerpta Medica DataBASE (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Science Direct. In addition we hand-searched reference lists of all identified articles. STUDY ELIGIBILITY CRITERIA: Studies were included if they reported gestational weight gain and energy intake in early and late gestation in women of any age with a singleton pregnancy. Search also encompassed journals emerging from both developed and developing countries. STUDY APPRAISAL AND SYNTHESIS METHODS: Studies were individually assessed for quality based on the Quality Criteria Checklist obtained from the Evidence Analysis Manual: Steps in the academy evidence analysis process. Publication bias was plotted by the use of a funnel plot with standard mean difference against standard error. Identified studies were meta-analyzed and stratified by body mass index, study design, dietary methodology, and country status (developed/developing) by the use of a random-effects model. RESULTS: Of 2487 articles screened, 18 studies met inclusion criteria. On average, women gained 12.0 (2.8) kg (standardized mean difference = 1.306, P < .0005) yet reported only a small increment in energy intake that did not reach statistical significance (∼475 kJ/day, standard mean difference = 0.266, P = .016). Irrespective of baseline body mass index, study design, dietary methodology, or country status, changes in energy intake were not significantly correlated to the amount of gestational weight gain (r = 0.321, P = .11). CONCLUSION: Despite rapid physiologic weight gain, women report little or no change in energy intake during pregnancy. Current recommendations to increase energy intake by ∼ 1000 kJ/day may, therefore, encourage excessive weight gain and adverse pregnancy outcomes.postprin
The Importance of Dietary Carbohydrate in Human Evolution
We propose that plant foods containing high quantities of starch were essential for the evolution of the human phenotype during the Pleistocene. Although previous studies have highlighted a stone tool-mediated shift from primarily plant-based to primarily meat-based diets as critical in the development of the brain and other human traits, we argue that digestible carbohydrates were also necessary to accommodate the increased metabolic demands of a growing brain. Furthermore, we acknowledge the adaptive role cooking played in improving the digestibility and palatability of key carbohydrates. We provide evidence that cooked starch, a source of preformed glucose, greatly increased energy availability to human tissues with high glucose demands, such as the brain, red blood cells, and the developing fetus. We also highlight the auxiliary role copy number variation in the salivary amylase genes may have played in increasing the importance of starch in human evolution following the origins of cooking. Salivary amylases are largely ineffective on raw crystalline starch, but cooking substantially increases both their energy-yielding potential and glycemia. Although uncertainties remain regarding the antiquity of cooking and the origins of salivary amylase gene copy number variation, the hypothesis we present makes a testable prediction that these events are correlate
Persistent Transport Barrier on the West Florida Shelf
Analysis of drifter trajectories in the Gulf of Mexico has revealed the
existence of a region on the southern portion of the West Florida Shelf (WFS)
that is not visited by drifters that are released outside of the region. This
so-called ``forbidden zone'' (FZ) suggests the existence of a persistent
cross-shelf transport barrier on the southern portion of the WFS. In this
letter a year-long record of surface currents produced by a Hybrid-Coordinate
Ocean Model simulation of the WFS is used to identify Lagrangian coherent
structures (LCSs), which reveal the presence of a robust and persistent
cross-shelf transport barrier in approximately the same location as the
boundary of the FZ. The location of the cross-shelf transport barrier undergoes
a seasonal oscillation, being closer to the coast in the summer than in the
winter. A month-long record of surface currents inferred from high-frequency
(HF) radar measurements in a roughly 60 km 80 km region on the WFS off
Tampa Bay is also used to identify LCSs, which reveal the presence of robust
transient transport barriers. While the HF-radar-derived transport barriers
cannot be unambiguously linked to the boundary of the FZ, this analysis does
demonstrate the feasibility of monitoring transport barriers on the WFS using a
HF-radar-based measurement system. The implications of a persistent cross-shelf
transport barrier on the WFS for the development of harmful algal blooms on the
shoreward side of the barrier are considered.Comment: Submitted to Geophysical Research Letter
Clumpy outer Galaxy molecular clouds and the steepening of the IMF
We report the results of high-resolution (~0.2 pc) CO(1-0) and CS(2-1)
observations of the central regions of three star-forming molecular clouds in
the far-outer Galaxy (~16 kpc from the Galactic Center): WB89 85 (Sh 2-127),
WB89 380, and WB89 437. We used the BIMA array in combination with IRAM 30-m
and NRAO 12-m observations. The GMC's in which the regions are embedded were
studied by means of KOSMA 3-m CO(2-1) observations. The properties the CO and
CS clumps are analyzed and compared with newly derived results of previously
published single-dish measurements of local clouds (OrionB South and Rosette).
We find that the slopes of the clump mass distributions (-1.28 and -1.49, for
WB89 85 and WB89 380, respectively) are somewhat less steep than found for most
local clouds, but similar to those of clouds which have been analyzed with the
same clumpfind program. We investigate the clump stability by using the virial
theorem, including all possible contributions (gravity, turbulence, magnetic
fields, and pressure due to the interclump gas). It appears that under
reasonable assumptions a combination of these forces would render most clumps
stable. Comparing only gravity and turbulence, we find that in the far-outer
Galaxy clouds, these forces are in equilibium (virial parameter alpha~1) for
clumps down to the lowest masses found (a few Msol). For clumps in the local
clouds alpha~1 only for clumps with masses larger than a few tens of Msol. Thus
it appears that in these outer Galaxy clumps gravity is the dominant force down
to a much lower mass than in local clouds, implying that gravitational collapse
and star formation may occur more readily even in the smallest clumps. Although
there are some caveats, due to the inhomogeneity of the data used, this might
explain the apparently steeper IMF found in the outer Galaxy.Comment: 29 pages, including 9 tables, 21 figures. Accepted for Astron.
Astrop
International Tables of Glycemic Index and Glycemic Load Values: 2008
OBJECTIVE—To systematically tabulate published and unpublished sources of reliable glycemic index (GI) values
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
From Social Democracy back to No Ideology? - The Scottish National Party and Ideological Change in a Multi-level Electoral Setting
This article examines the development of ideology in the Scottish National Party since its formation in 1934, focusing on the recent period of the party’s history. It examines ideological development within the context of the party’s adaptation to multi-level elections and party system, especially in the decade since devolution began in 1999. It also provides a brief consideration of the party’s office success and governmental performance since 2007 to examine the effect of office on the SNP and its autonomy goal of Scottish independence
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