Subglacial drainage processes at a High Arctic polythermal valley glacier

Peer reviewedPublisher PD

PyWiFeS: a rapid data reduction pipeline for the Wide Field Spectrograph (WiFeS)

We present PyWiFeS, a new Python-based data reduction pipeline for the Wide Field Spectrograph (WiFeS). PyWiFeS consists of a series of core data processing routines built on standard scientific Python packages commonly used in astronomical applications. Included in PyWiFeS is an implementation of a new global optical model of the spectrograph which provides wavelengths solutions accurate to ?0.05 Å (RMS) across the entire detector. The core PyWiFeS package is designed to be scriptable to enable batch processing of large quantities of data, and we present a default format for handling of observation metadata and scripting of data reduction

Liver Transplantation for Advanced Liver Disease with Alpha-1antitrypsin Deficiency

ALPHA-1-antitrypsin deficiency associated with chronic obstructive airway disease was recognized in 1963 by Laurell and Ericksson.1 In 1969, Sharp2 described the first cases of alpha-1-antitrypsin-deficiency disease in children with cirrhosis. Since then, this inborn error has been recognized as one of the more common factors in cirrhosis of infancy and childhood,3 including “neonatal hepatitis.”4 Alpha-1-antitrypsin is a glycoprotein that accounts for a major portion of the alpha-1 globulin fraction of the serum.5 It is responsible for approximately 90 per cent of the antitrypsin activity6 of the serum, and it also inhibits several other plasma enzymes, including plasmin,7 elastase,8 collagenase,9 and. © 1980, Massachusetts Medical Society. All rights reserved

An integrated approach to use genetic resources for resurrection plants to enhance drought tolerance in breeding-extension programs [abstract]

Only abstract of poster available.Track V: BiomassThe ultimate goals of this project are to gain a basic understanding of the unique gene and gene regulatory networks that are necessary and sufficient for vegetative tissues to withstand dehydration and then rapidly recover upon rehydration and to use the knowledge gained to develop crops, maize and forage grasses that maintain biomass production under drought condition. Our approach is to combine comparative genomics and phylogenetics to identify genes and gene networks that are adaptive and central to the tolerance of cellular dehydration. This involves the use of resurrection species as models for dehydration tolerance coupled with a suite of comparative bioinformatic tools that allows for the phylogenetic assessment of gene expression patterns in response to dehydration and rehydration. Once the key genetic elements have been identified and assessed we will use a transgenic functional assessment of their involvement in the phenotype, both at a molecular and physiological level, of drought tolerance. One of our key resurrection species is the South African grass Sporobolus stapfianus, which is capable of surviving -240 MPa of water deficit (a hundred times lower than most crop plants). This plant not only serves as a model for monocot crops such as maize and switchgrass, our major targets for crop improvement, but also serves as a direct possibility for an alternate forage grass and biomass source. The improvement of biomass production under drought conditions is not only important for sustainable biofuel production but also for food and energy security. Funded by a CSREES-NRI Grant of $450,000 over three years to PI Mel Oliver USDA-ARS-PGRU Columbia, CoPIs Robert Sharp, University of Missouri; John Cushman, University of Nevada, Reno; Paxton Payton, USDA-ARS-PSRU Lubbock

The SCUBA Bright Quasar Survey (SBQS): 850micron observations of the z>4 sample

We present initial results of a new, systematic search for massive star-formation in the host galaxies of the most luminous and probably most massive z>=4 radio-quiet quasars (M(B) 10^13Lsun). A total of 38 z>=4 radio-quiet quasars have been observed at the JCMT using SCUBA at 850microns: 8 were detected (>3sigma) with S(850microns)>~ 10mJy (submillimetre-loud). The new detections almost triple the number of optically selected, submillimetre-loud z>~4 radio-quiet quasars known to date. We include a detailed description of how our quasar sample is defined in terms of radio and optical properties. There is no strong evidence for trends in either detectability or 850microns flux with absolute magnitude, M(B). We find that the weighted mean flux of the undetected sources is 2.0 +/- 0.6mJy, consistent with an earlier estimate of \~3mJy based on more sensitive observations of a sample z>~4 radio-quiet quasars (McMahon et al., 1999). This corresponds to an inferred starformation rate of \~1000Msun/yr, similar to Arp220. The typical starformation timescale for the submillimetre-bright sources is ~1Gyr, 10 times longer than the typical accretion-driven e-folding timescale of ~5x10^7 years. Our 850micron detection of the z=4.4 quasar PSS J1048+4407 when analysed in conjunction with 1.2mm single-dish and interferometric observations suggests that this source is resolved on angular scales of 1-2" (6-12 kpc). In addition, we present a new optical spectrum of this source, identifying it as a broad absorption line (BAL) quasar. The new redshift is outside that covered in a recent CO line search by Guilloteau et al., (1999), highlighting the need for accurate redshifts for the obervation and interpretation of high-redshift line studies.Comment: 16 pages, 11 figures. Accepted by Monthly Notices of the Royal Astronomical Societ

A High-Throughput Screen Identifies a New Natural Product with Broad-Spectrum Antibacterial Activity

Due to the inexorable invasion of our hospitals and communities by drug-resistant bacteria, there is a pressing need for novel antibacterial agents. Here we report the development of a sensitive and robust but low-tech and inexpensive high-throughput metabolic screen for novel antibiotics. This screen is based on a colorimetric assay of pH that identifies inhibitors of bacterial sugar fermentation. After validation of the method, we screened over 39,000 crude extracts derived from organisms that grow in the diverse ecosystems of Costa Rica and identified 49 with reproducible antibacterial effects. An extract from an endophytic fungus was further characterized, and this led to the discovery of three novel natural products. One of these, which we named mirandamycin, has broad-spectrum antibacterial activity against $Escherichia$ $coli$, $Pseudomonas$ $aeruginosa$, $Vibrio$ $cholerae$, methicillin-resistant $Staphylococcus$ $aureus$, and $Mycobacterium$ $tuberculosis$. This demonstrates the power of simple high throughput screens for rapid identification of new antibacterial agents from environmental samples.Version of Recor

High star formation rates as the origin of turbulence in early and modern disk galaxies

High spatial and spectral resolution observations of star formation and kinematics in early galaxies have shown that two-thirds are massive rotating disk galaxies with the remainder being less massive non-rotating objects. The line of sight averaged velocity dispersions are typically five times higher than in today's disk galaxies. This has suggested that gravitationally-unstable, gas-rich disks in the early Universe are fuelled by cold, dense accreting gas flowing along cosmic filaments and penetrating hot galactic gas halos. However these accreting flows have not been observed, and cosmic accretion cannot power the observed level of turbulence. Here we report on a new sample of rare high-velocity-dispersion disk galaxies we have discovered in the nearby Universe where cold accretion is unlikely to drive their high star-formation rates. We find that the velocity dispersion is most fundamentally correlated with their star-formation rates, and not their mass nor gas fraction, which leads to a new picture where star formation itself is the energetic driver of galaxy disk turbulence at all cosmic epochs.Comment: 9 pages, 2 figures, Supplimentary Info available at: http://pulsar.swin.edu.au/~agreen/nature/sigma_mean_arXiv.pdf. Accepted for publication in Natur

Plasmodium falciparum associated with severe childhood malaria preferentially expresses PfEMP1 encoded by group A var genes.

Parasite-encoded variant surface antigens (VSAs) like the var gene-encoded Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family are responsible for antigenic variation and infected red blood cell (RBC) cytoadhesion in P. falciparum malaria. Parasites causing severe malaria in nonimmune patients tend to express a restricted subset of VSA (VSA(SM)) that differs from VSA associated with uncomplicated malaria and asymptomatic infection (VSA(UM)). We compared var gene transcription in unselected P. falciparum clone 3D7 expressing VSA(UM) to in vitro-selected sublines expressing VSA(SM) to identify PfEMP1 responsible for the VSA(SM) phenotype. Expression of VSA(SM) was accompanied by up-regulation of Group A var genes. The most prominently up-regulated Group A gene (PFD1235w/MAL7P1.1) was translated into a protein expressed on the infected RBC surface. The proteins encoded by Group A var genes, such as PFD1235w/MAL7P1.1, appear to be involved in the pathogenesis of severe disease and are thus attractive candidates for a vaccine against life-threatening P. falciparum malaria

Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)

The Torngat Mountains National Park, northern Labrador, Canada, contains more than 120 small glaciers: the only remaining glaciers in continental northeast North America. These small cirque glaciers exist in a unique topo-climatic setting, experiencing temperate maritime summer conditions yet very cold and dry winters, and may provide insights into the deglaciation dynamics of similar small glaciers in temperate mountain settings. Due to their size and remote location, very little information exists regarding the health of these glaciers. Just a single study has been published on the contemporary glaciology of the Torngat Mountains, focusing on net mass balances from 1981 to 1984. This paper addresses the extent to which glaciologically relevant climate variables have changed in northern Labrador in concert with 20th-century Arctic warming, and how these changes have affected Torngat Mountain glaciers. Field surveys and remote-sensing analyses were used to measure regional glacier area loss of 27 % from 1950 to 2005, substantial rates of ice surface thinning (up to 6 m yr⁻¹) and volume losses at Abraham, Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances appear to be controlled by variations in winter precipitation and, increasingly, by strong summer and autumn atmospheric warming since the early 1990s, though further observations are required to fully understand mass balance sensitivities. This study provides the first comprehensive contemporary assessment of Labrador glaciers and will inform both regional impact assessments and syntheses of global glacier mass balance