Far-Ultraviolet Radiation from Elliptical Galaxies

Far-ultraviolet radiation is a ubiquitous, if unanticipated, phenomenon in elliptical galaxies and early-type spiral bulges. It is the most variable photometric feature associated with old stellar populations. Recent observational and theoretical evidence shows that it is produced mainly by low-mass, small-envelope, helium-burning stars in extreme horizontal branch and subsequent phases of evolution. These are probably descendents of the dominant, metal rich population of the galaxies. Their lifetime UV outputs are remarkably sensitive to their physical properties and hence to the age and the helium and metal abundances of their parents. UV spectra are therefore exceptionally promising diagnostics of old stellar populations, although their calibration requires a much improved understanding of giant branch mass loss, helium enrichment, and atmospheric diffusion.Comment: 46 pages; includes LaTeX text file, 9 PS figures, 1 JPG figure, 2 style files. Full resolution figures and PS version available at http://www.astro.virginia.edu/~rwo/araa99/. Article to appear in Annual Reviews of Astronomy & Astrophysics, 199

A Fly in the Ointment: Evaluation of Traditional Use of Plants to Repel and Kill Blowfly Larvae in Fermented Fish

Introduction: In rural areas in Laos, fly larvae infestations are common in fermenting fish. Blowflies (Chrysomyamegacephala, Diptera: Calliphoridae) are attracted to oviposit (and/or larviposit) onto fermenting fish which results ininfestations with fly larvae. Knowledge of traditional use of plants to repel larvae during the production of fermented fish iscommon and widespread in Lao PDR. Research Questions: How effective are the most salient species in repelling, and killing fly larvae in fermenting fish? Material and Methods: The three plant species most frequently reported to repel fly larvae during an ethnobotanical surveythroughout Lao PDR were tested for repellence and larvicidal activity of fly larvae infesting fermented fish. The lethality andrepellence of Tadehagi triquetrum (L.) H. Ohashi (Fabaceae), Uraria crinita (L.) Desv. ex DC. (Fabaceae) and Bambusa multiplex(Lour.) Raeusch. ex Schult. & Schult. f. (Poaceae) were tested in an experimental design using fermenting fish in Vientiane,Lao PDR. Results: The repellent effect of fresh material of T. triquetrum and U. crinita, and the larvicidal effect of fresh B. multiplex, issignificantly more effective than that of dried material of the same species, and the total effect (repellence and larvicidaleffect combined) for each of the three species was significantly more effective for fresh than for dry material. Fresh materialof T. triquetrum, U. crinita, or B. multiplex added on top of the fermenting fish repelled 50%, 54%, 37%, and killed 22%, 28%,and 40% of fly larvae. The total effect was not significantly different per species at 72%, 82%, and 77%, respectively. Discussion and Conclusions: The three most salient species are effective in repelling and killing fly larvae in the productionof fermented fish, and may be essential to augment food safety during traditional fermentation in open jars

Discovery of molecular hydrogen in a high-velocity cloud of the Galactic halo

We report the discovery of molecular hydrogen absorption in a Galactic high-velocity cloud (HVC) in the direction of the Large Magellanic Cloud. For the same HVC we derive an iron abundance which is half of the solar value. Thus, all evidence points to a Galactic origin for high-velocity cloud complex in front of the LMC.Comment: Published in Nature, this week; 14 pages, 3 figure

String Theory on Warped AdS_3 and Virasoro Resonances

We investigate aspects of holographic duals to time-like warped AdS_3 space-times--which include G\"odel's universe--in string theory. Using worldsheet techniques similar to those that have been applied to AdS_3 backgrounds, we are able to identify space-time symmetry algebras that act on the dual boundary theory. In particular, we always find at least one Virasoro algebra with computable central charge. Interestingly, there exists a dense set of points in the moduli space of these models in which there is actually a second commuting Virasoro algebra, typically with different central charge than the first. We analyze the supersymmetry of the backgrounds, finding related enhancements, and comment on possible interpretations of these results. We also perform an asymptotic symmetry analysis at the level of supergravity, providing additional support for the worldsheet analysis.Comment: 24 pages + appendice

Holographic c-theorems in arbitrary dimensions

We re-examine holographic versions of the c-theorem and entanglement entropy in the context of higher curvature gravity and the AdS/CFT correspondence. We select the gravity theories by tuning the gravitational couplings to eliminate non-unitary operators in the boundary theory and demonstrate that all of these theories obey a holographic c-theorem. In cases where the dual CFT is even-dimensional, we show that the quantity that flows is the central charge associated with the A-type trace anomaly. Here, unlike in conventional holographic constructions with Einstein gravity, we are able to distinguish this quantity from other central charges or the leading coefficient in the entropy density of a thermal bath. In general, we are also able to identify this quantity with the coefficient of a universal contribution to the entanglement entropy in a particular construction. Our results suggest that these coefficients appearing in entanglement entropy play the role of central charges in odd-dimensional CFT's. We conjecture a new c-theorem on the space of odd-dimensional field theories, which extends Cardy's proposal for even dimensions. Beyond holography, we were able to show that for any even-dimensional CFT, the universal coefficient appearing the entanglement entropy which we calculate is precisely the A-type central charge.Comment: 62 pages, 4 figures, few typo's correcte

A Yeast Two-Hybrid Screen for SYP-3 Interactors Identifies SYP-4, a Component Required for Synaptonemal Complex Assembly and Chiasma Formation in Caenorhabditis elegans Meiosis

The proper assembly of the synaptonemal complex (SC) between homologs is critical to ensure accurate meiotic chromosome segregation. The SC is a meiotic tripartite structure present from yeast to humans, comprised of proteins assembled along the axes of the chromosomes and central region (CR) proteins that bridge the two chromosome axes. Here we identify SYP-4 as a novel structural component of the SC in Caenorhabditis elegans. SYP-4 interacts in a yeast two-hybrid assay with SYP-3, one of components of the CR of the SC, and is localized at the interface between homologs during meiosis. SYP-4 is essential for the localization of SYP-1, SYP-2, and SYP-3 CR proteins onto chromosomes, thereby playing a crucial role in the stabilization of pairing interactions between homologous chromosomes. In the absence of SYP-4, the levels of recombination intermediates, as indicated by RAD-51 foci, are elevated in mid-prophase nuclei, and crossover recombination events are significantly reduced. The lack of chiasmata observed in syp-4 mutants supports the elevated levels of chromosome nondisjunction manifested in high embryonic lethality. Altogether our findings place SYP-4 as a central player in SC formation and broaden our understanding of the structure of the SC and its assembly

Treatment of Aspergillus fumigatus in Patients with Cystic Fibrosis: A Randomized, Placebo-Controlled Pilot Study

Many patients with cystic fibrosis develop persistent airway infection/colonization with Aspergillus fumigatus, however the impact of A. fumigatus on clinical outcomes remains unclear. The objective of this study was to determine whether treatment directed against Aspergillus fumigatus improves pulmonary function and clinical outcomes in patients with cystic fibrosis (CF).We performed a double-blind randomized placebo-controlled pilot clinical trial involving 35 patients with CF whose sputum cultures were chronically positive for A. fumigatus. Participants were centrally randomized to receive either oral itraconazole 5 mg/kg/d (N = 18) or placebo (N = 17) for 24 weeks. The primary outcome was the proportion of patients who experienced a respiratory exacerbation requiring intravenous antibiotics over the 24 week treatment period. Secondary outcomes included changes in FEV(1) and quality of life.Over the 24 week treatment period, 4 of 18 (22%) patients randomized to itraconazole experienced a respiratory exacerbation requiring intravenous antibiotics, compared to 5 of 16 (31%) placebo treated patients, P = 0.70. FEV(1) declined by 4.62% over 24 weeks in the patients randomized to itraconazole, compared to a 0.32% improvement in the placebo group (between group difference = -4.94%, 95% CI: -15.33 to 5.45, P = 0.34). Quality of life did not differ between the 2 treatment groups throughout the study. Therapeutic itraconazole blood levels were not achieved in 43% of patients randomized to itraconazole.We did not identify clinical benefit from itraconazole treatment for CF patients whose sputum was chronically colonized with A. fumigatus. Limitations of this pilot study were its small sample size, and failure to achieve therapeutic levels of itraconazole in many patients.ClinicalTrials.gov NCT00528190

An upper limit to the masses of stars

There is no accepted upper mass limit for stars. Such a basic quantity escapes both theory, because of incomplete understanding of star formation, and observation, because of incompleteness in surveying the Galaxy. The Arches cluster is ideal for such a test, being massive enough to expect stars at least as massive as 400 solar masses, and young enough for its most massive members to still be visible. It is old enough to be free of its natal molecular cloud, and close enough, and at a well-established distance, for us to discern its individual stars. Here I report an absence of stars with initial masses greater than 130 M_Sun in the Arches cluster, where the typical mass function predicts 18. I conclude that this indicates a firm limit of 150 M_Sun for stars as the probability that the observations are consistent with no limit is 10^-8.Comment: To appear in Nature, March 10, 2005, Vol. 34, No. 7030, 192 (ST ScI Eprint #1645). More files can be found at http://www.stsci.edu/~fige

Bone pain and extremely low bone mineral density due to severe vitamin D deficiency in celiac disease

Case report A 29-year-old wheelchair-bound woman was presented to us by the gastroenterologist with suspected osteomalacia. She had lived in the Netherlands all her life and was born of Moroccan parents. Her medical history revealed iron deficiency, growth retardation, and celiac disease, for which she was put on a gluten-free diet. She had progressive bone pain since 2 years, difficulty with walking, and about 15 kg weight loss. She had a short stature, scoliosis, and pronounced kyphosis of the spine and poor condition of her teeth. Laboratory results showed hypocalcemia, an immeasurable serum25-hydroxyvitamin D level, and elevated parathyroid hormone and alkaline phosphatase levels. Spinal radiographs showed unsharp, low contrast vertebrae. Bone mineral density measurement at the lumbar spine and hip showed a T-score of -6.0 and -6.5, respectively. A bone scintigraphy showed multiple hotspots in ribs, sternum, mandible, and long bones. A duodenal biopsy revealed villous atrophy (Marsh 3C) and positive antibodies against endomysium, transglutaminase, and gliadin, compatible with active celiac disease. A bone biopsy showed severe osteomalacia but normal bone volume. She was treated with calcium intravenously and later orally. Furthermore, she was treated with high oral doses of vitamin D and a gluten-free diet. After a few weeks of treatment, her bone pain decreased, and her muscle strength improved. Discussion In this article, the pathophysiology and occurrence of osteomalacia as a complication of celiac disease are discussed. Low bone mineral density can point to osteomalacia as well as osteoporosis. © International Osteoporosis Foundation and National Osteoporosis Foundation 2011