339 research outputs found
Civil War Treasures: The Civil War Saga Of The Wall Family Of Clinton, Louisiana
While it might be peculiar to describe a collection of antebellum, Civil War, and postbellum letters as new, such an odd characterization would not be unreasonable for the Wall Family Papers in the LSU Libraries Special Collections. Acquired at auction last October, the papers are comprised of 54...
The Color Variability of Quasars
We quantify quasar color-variability using an unprecedented variability
database - ugriz photometry of 9093 quasars from SDSS Stripe 82, observed over
8 years at ~60 epochs each. We confirm previous reports that quasars become
bluer when brightening. We find a redshift dependence of this blueing in a
given set of bands (e.g. g and r), but show that it is the result of the flux
contribution from less-variable or delayed emission lines in the different SDSS
bands at different redshifts. After correcting for this effect, quasar
color-variability is remarkably uniform, and independent not only of redshift,
but also of quasar luminosity and black hole mass. The color variations of
individual quasars, as they vary in brightness on year timescales, are much
more pronounced than the ranges in color seen in samples of quasars across many
orders of magnitude in luminosity. This indicates distinct physical mechanisms
behind quasar variability and the observed range of quasar luminosities at a
given black hole mass - quasar variations cannot be explained by changes in the
mean accretion rate. We do find some dependence of the color variability on the
characteristics of the flux variations themselves, with fast, low-amplitude,
brightness variations producing more color variability. The observed behavior
could arise if quasar variability results from flares or ephemeral hot spots in
an accretion disc.Comment: Accepted for publication in ApJ - in press, 17 pages, 14 figures -
v2: abstract typo corrected & reference clean-u
Disentangling hydroxynitrile glucoside biosynthesis in a barley (Hordeum vulgare) metabolon provides access to elite malting barleys for ethyl carbamate-free whisky production
Barley produces several specialized metabolites, including five α-, β-, and γ-hydroxynitrile glucosides (HNGs). In malting barley, presence of the α-HNG epiheterodendrin gives rise to undesired formation of ethyl carbamate in the beverage production, especially after distilling. Metabolite-GWAS identified QTLs and underlying gene candidates possibly involved in the control of the relative and absolute content of HNGs, including an undescribed MATE transporter. By screening 325 genetically diverse barley accessions, we discovered three H. vulgare ssp. spontaneum (wild barley) lines with drastic changes in the relative ratios of the five HNGs. Knock-out (KO)-lines, isolated from the barley FIND-IT resource and each lacking one of the functional HNG biosynthetic genes (CYP79A12, CYP71C103, CYP71C113, CYP71U5, UGT85F22 and UGT85F23) showed unprecedented changes in HNG ratios enabling assignment of specific and mutually dependent catalytic functions to the biosynthetic enzymes involved. The highly similar relative ratios between the five HNGs found across wild and domesticated barley accessions indicate assembly of the HNG biosynthetic enzymes in a metabolon, the functional output of which was reconfigured in the absence of a single protein component. The absence or altered ratios of the five HNGs in the KO-lines did not change susceptibility to the fungal phytopathogen Pyrenophora teres causing net blotch. The study provides a deeper understanding of the organization of HNG biosynthesis in barley and identifies a novel, single gene HNG-0 line in an elite spring barley background for direct use in breeding of malting barley, eliminating HNGs as a source of ethyl carbamate formation in whisky production.</p
Migraine aura or transient ischemic attacks? A five-year follow-up case-control study of women with transient central nervous system disorders in pregnancy
<p>Abstract</p> <p>Background</p> <p>Migraine aura may be difficult to differentiate from transient ischemic attacks and other transient neurological disorders in pregnant women. The aims of the present study were to investigate and diagnose all pregnant women with transient neurological disorders of suspected central nervous system origin, and to compare this group with a control group of pregnant women with regard to vascular risk factors and prognosis.</p> <p>Methods</p> <p>During a 28 month period, 41 patients were detected with transient neurological symptoms during pregnancy. These were studied in detail with thorough clinical and laboratory investigations in order to make a certain diagnosis and to evaluate whether the episodes might be of a vascular nature. For comparison, the same investigations were performed in 41 pregnant controls. To assess the prognosis, both patients and controls were followed with questionnaires every year for five years.</p> <p>Results</p> <p>Migraine with aura was the most common cause of symptoms during pregnancy, occurring in 34 patients, while 2 were diagnosed with stroke, 2 with carpal tunnel syndrome, 1 with partial epilepsy, 1 with multiple sclerosis and 1 with presyncope. Patients had more headache before pregnancy than controls, but the average levels of vascular risk factors were similar. None of the patients or the controls reported cerebrovascular episodes during the five-year follow-up.</p> <p>Conclusion</p> <p>The diagnosis of migraine aura was difficult because for many patients it was their first ever attack and headache tended to be absent or of non-migraineous type. The aura features were more complex, with several aura symptoms and a higher prevalence of sensory and dysphasic aura than usual. Gradually developing aura symptoms, or different aura symptoms occurring in succession as described in the International Classification of Headache Disorders, seem to be useful for differentiating aura from other transient disorders. A meticulous history and clinical neurological examination are more useful than routine supplementary investigations for cerebrovascular disease. The five-year follow-up clearly indicates that migraine with aura in pregnancy usually has a good prognosis with regard to cerebrovascular events.</p
Thyroid Function and Body Weight: A Community-Based Longitudinal Study
OBJECTIVE: Body weight and overt thyroid dysfunction are associated. Cross-sectional population-based studies have repeatedly found that thyroid hormone levels, even within the normal reference range, might be associated with body weight. However, for longitudinal data, the association is less clear. Thus, we tested the association between serum thyrotropin (TSH) and body weight in a community-based sample of adult persons followed for 11 years. METHODS: A random sample of 4,649 persons aged 18-65 years from a general population participated in the DanThyr study in 1997-8. We included 2,102 individuals who participated at 11-year follow-up, without current or former treatment for thyroid disease and with measurements of TSH and weight at both examinations. Multiple linear regression models were used, stratified by sex and adjusted for age, smoking status, and leisure time physical activity. RESULTS: Baseline TSH concentration was not associated with change in weight (women, P = 0.17; men, P = 0.72), and baseline body mass index (BMI) was not associated with change in TSH (women, P = 0.21; men, P = 0.85). Change in serum TSH and change in weight were significantly associated in both sexes. Weight increased by 0.3 kg (95% confidence interval [CI] 0.1, 0.4, P = 0.005) in women and 0.8 kg (95% CI 0.1, 1.4, P = 0.02) in men for every one unit TSH (mU/L) increase. CONCLUSIONS: TSH levels were not a determinant of future weight changes, and BMI was not a determinant for TSH changes, but an association between weight change and TSH change was present
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