876 research outputs found
Migraines During Pregnancy Linked to Stroke and Vascular Diseases: US Population-Based Case-Control Study
Objective To examine the association between migraine and cardiovascular diseases during pregnancy. Design US population based case-control study. Setting Nationwide inpatient sample, from the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality. Population 18 345 538 pregnancy related discharges from 2000 to 2003. Main outcome measures Diagnosis of migraine, as identified by ICD-9 codes 346.0 and 346.1. Stroke and other vascular diseases were identified by using standard ICD-9 codes. Results From the hospital discharges with a pregnancy discharge code, 33 956 migraine codes were identified: 185 per 100 000 deliveries. Diagnoses that were jointly associated with migraine codes during pregnancy (excluding pre-eclampsia) were stroke (odds ratio 15.05, 95% confidence interval 8.26 to 27.4), myocardial infarction/heart disease (2.11, 1.76 to 2.54), pulmonary embolus/venous thromboembolism (3.23, 2.06 to 7.07), and hypertension (8.61, 6.43 to 11.54), as well as preeclampsia/gestational hypertension (2.29, 2.13 to 2.46), smoking (2.85, 2.53 to 3.21), and diabetes (1.96, 1.64 to 2.35). However, migraine was not associated with several non-vascular diagnoses (pneumonia, transfusions, postpartum infection or haemorrhage). Conclusions In this large, population based sample of pregnant women admitted to hospital, a strong relation existed between active peripartum migraine and vascular diagnoses during pregnancy. Because these data do not allow determination of which came first, migraine or the vascular condition, prospective studies of pregnant women are needed to explore this association further
CVD growth and properties of boron phosphide on 3C-SiC
Citation: CVD growth and properties of boron phosphide on 3C-SiC, B. Padavala, C.D.Frye, X. Wang, B. Raghothamachar, and J.H. Edgar, Journal of Crystal Growth, volume 449 pp. 15-21 (2016).Improving the crystalline quality of boron phosphide (BP) is essential for realizing its full potential in semiconductor device applications. In this study, 3C-SiC was tested as a substrate for BP epitaxy. BP films were grown on 3C-SiC(100)/Si, 3C-SiC(111)/Si, and 3C-SiC(111)/4H-SiC(0001) substrates in a horizontal chemical vapor deposition (CVD) system. Films were produced with good crystalline orientation and morphological features in the temperature range of 1000â1200 °C using a PH3+B2H6+H2 mixture. Rotational twinning was absent in the BP due to the crystal symmetry-matching with 3C-SiC. Confocal 3D Raman imaging of BP films revealed primarily uniform peak shift and peak widths across the scanned area, except at defects on the surface. Synchrotron white beam X-ray topography showed the epitaxial relationship between BP and 3C-SiC was (100)(100)ă011ăă011ăBP||(100)(100)ă011ăă011ă3C-SiC and (111)(111)View the MathML sourceă112Ì
ăBP||(111)(111)View the MathML sourceă112Ì
ă3C-SiC. Scanning electron microscopy, Raman spectroscopy and X-ray diffraction analysis indicated residual tensile strain in the films and improved crystalline quality at temperatures below 1200 °C. These results indicated that BP properties could be further enhanced by employing high quality bulk 3C-SiC or 3C-SiC epilayers on 4H-SiC substrates
Effects of quality grade, aging period, blade tenderization, and degree of doneness on tenderness of inside round steaks
We used 162 inside rounds to determine the
influence of different quality grades, postmortem
aging periods, blade tenderization passes, and
degree of doneness on thawing and cooking
losses and Warner-Bratzler Shear force (WBS,
tenderness). Select (SEL), Choice (CHO), and
Certified Angus Beefâą (CAB) inside rounds
were aged for 7, 14, or 21 days and not tenderized
(0X) or blade tenderized one (1X) or two
(2X) times. Steaks from each inside round
were assigned randomly to final endpoint cooking
temperatures of 150, 160, and 170°F.
Percentage of thawing loss was higher (P<.05)
for steaks aged 7 days than steaks aged 14 and
21 days. For CHO steaks only, cooking loss
was higher (P<.05) for the 2X group compared
to the 0X and 1X groups. Steaks aged 14 and
21 days had lower (P<.05) WBS than steaks
aged 7 days. Cooking loss and WBS were
higher (P<.05) with each increase in endpoint
cooking temperature. Postmortem aging (14 or
21 days) and lower endpoint cooking temperatures
were the most effective methods to improve
WBS of inside round steaks
The Collapse of Large Extra Dimensions
In models of spacetime that are the product of a four-dimensional spacetime
with an ``extra'' dimension, there is the possibility that the extra dimension
will collapse to zero size, forming a singularity. We ask whether this collapse
is likely to destroy the spacetime. We argue, by an appeal to the
four-dimensional cosmic censorship conjecture, that--at least in the case when
the extra dimension is homogeneous--such a collapse will lead to a singularity
hidden within a black string. We also construct explicit initial data for a
spacetime in which such a collapse is guaranteed to occur and show how the
formation of a naked singularity is likely avoided.Comment: Uses revtex
-- mixing and oblique corrections in an model
A global fit for experiments is included in this revised version.Comment: IFP-460-UNC, TRI-PP-93-11, 20 pages, 2 figures are appende
Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating
Traditionally stellar radiation has been the only heat source considered
capable of determining global climate on long timescales. Here we show that
terrestrial exoplanets orbiting low-mass stars may be tidally heated at high
enough levels to induce a runaway greenhouse for a long enough duration for all
the hydrogen to escape. Without hydrogen, the planet no longer has water and
cannot support life. We call these planets "Tidal Venuses," and the phenomenon
a "tidal greenhouse." Tidal effects also circularize the orbit, which decreases
tidal heating. Hence, some planets may form with large eccentricity, with its
accompanying large tidal heating, and lose their water, but eventually settle
into nearly circular orbits (i.e. with negligible tidal heating) in the
habitable zone (HZ). However, these planets are not habitable as past tidal
heating desiccated them, and hence should not be ranked highly for detailed
follow-up observations aimed at detecting biosignatures. Planets orbiting stars
with masses <0.3 solar masses may be in danger of desiccation via tidal
heating. We apply these concepts to Gl 667C c, a ~4.5 Earth-mass planet
orbiting a 0.3 solar mass star at 0.12 AU. We find that it probably did not
lose its water via tidal heating as orbital stability is unlikely for the high
eccentricities required for the tidal greenhouse. As the inner edge of the HZ
is defined by the onset of a runaway or moist greenhouse powered by radiation,
our results represent a fundamental revision to the HZ for non-circular orbits.
In the appendices we review a) the moist and runaway greenhouses, b) hydrogen
escape, c) stellar mass-radius and mass-luminosity relations, d) terrestrial
planet mass-radius relations, and e) linear tidal theories. [abridged]Comment: 59 pages, 11 figures, accepted to Astrobiology. New version includes
an appendix on the water loss timescal
Trematode Infections inLittorina littoreaon the New Hampshire Coast
The prevalence of parasite infections in Littorina littorea (Common Periwinkle) was examined at 16 rocky intertidal sites along the New Hampshire coastline over three summers (2006 to 2008). We sampled over a relatively small spatial scale (21 km) and expected that the prevalence of infections in L. littorea would be similar between sites over this sampling area. In total, 1983 snails were collected from areas at mean low water during spring tides. Snail size (mm), gender, and type of parasitic infection were noted for all snails. Eleven percent of snails collected were infected with rediae and cercariae of the trematodes Cryptocotyle lingua or Cercaria parvicaudata; one snail had a double infection of both trematodes. The prevalence of infection at sites ranged from 1.9% to 30.1%. At all sites, female snails outnumbered male snails, and a greater proportion of females were infected than males. Large snails were more likely to be infected with trematodes at 3 sites, while a higher level of infection was found in small snails at 1 site. Snails at wave-protected sites were more likely to be infected than snails at wave-exposed sites. No relationship was found between the number of gulls at a site and the prevalence of infection. Although temporal variation in levels of prevalence in parasitic infections may explain some of our site-to-site differences, our data show large spatial variation of parasite prevalence in L. littorea over a minimum distance of 0.5 km and provide a foundation to test hypotheses concerning the susceptibility of female and immature (small) snails to infection
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