Sensitivity of a climatologically-driven sea ice model to the ocean heat flux

Ocean heat flux sensitivity was studied on a numerical model of sea ice covering the Weddell Sea region of the southern ocean. The model is driven by mean monthly climatological atmospheric variables. For each model run, the ocean heat flux is uniform in both space and time. Ocean heat fluxes below 20 W m to the minus 2 power do not provide sufficient energy to allow the ice to melt to its summertime thicknesses and concentrations by the end of the 14 month simulation, whereas ocean heat fluxes of 30 W m to the minus 2 power and above result in too much ice melt, producing the almost total disappearance of ice in the Weddell Sea by the end of the 14 months. These results are dependent on the atmospheric forcing fields

Aperture synthesis for microwave radiometers in space

A technique is described for obtaining passive microwave measurements from space with high spatial resolution for remote sensing applications. The technique involves measuring the product of the signal from pairs of antennas at many different antenna spacings, thereby mapping the correlation function of antenna voltage. The intensity of radiation at the source can be obtained from the Fourier transform of this correlation function. Theory is presented to show how the technique can be applied to large extended sources such as the Earth when observed from space. Details are presented for a system with uniformly spaced measurements

The Montage Image Mosaic Service: Custom Image Mosaics On-Demand

The Montage software suite has proven extremely useful as a general engine for reprojecting, background matching, and mosaicking astronomical image data from a wide variety of sources. The processing algorithms support all common World Coordinate System (WCS) projections and have been shown to be both astrometrically accurate and flux conserving. The background ‘matching’ algorithm does not remove background flux but rather finds the best compromise background based on all the input and matches the individual images to that. The Infrared Science Archive (IRSA), part of the Infrared Processing and Analysis Center (IPAC) at Caltech, has now wrapped the Montage software as a CGI service and provided a compute and request management infrastructure capable of producing approximately 2 TBytes / day of image mosaic output (e.g. from 2MASS and SDSS data). Besides the basic Montage engine, this service makes use of a 16-node LINUX cluster (dual processor, dual core) and the ROME request management software developed by the National Virtual Observatory (NVO). ROME uses EJB/database technology to manage user requests, queue processing and load balance between users, and managing job monitoring and user notification. The Montage service will be extended to process userdefined data collections, including private data uploads

A Cost-Benefit Study of Doing Astrophysics On The Cloud: Production of Image Mosaics

Utility grids such as the Amazon EC2 and Amazon S3 clouds offer computational and storage resources that can be used on-demand for a fee by compute- and data-intensive applications. The cost of running an application on such a cloud depends on the compute, storage and communication resources it will provision and consume. Different execution plans of the same application may result in significantly different costs. We studied via simulation the cost performance trade-offs of different execution and resource provisioning plans by creating, under the Amazon cloud fee structure, mosaics with the Montage image mosaic engine, a widely used data- and compute-intensive application. Specifically, we studied the cost of building mosaics of 2MASS data that have sizes of 1, 2 and 4 square degrees, and a 2MASS all-sky mosaic. These are examples of mosaics commonly generated by astronomers. We also study these trade-offs in the context of the storage and communication fees of Amazon S3 when used for long-term application data archiving. Our results show that by provisioning the right amount of storage and compute resources cost can be significantly reduced with no significant impact on application performance

As-built design specifications of the LANDSAT Imagery Verification and Extraction System (LIVES). Volume 1: Test and appendices

There are no author-identified significant results in this report

Conditional mutants of Staphylococcus aureus defective in cell wall precursor synthesis

Temperature-sensitive (ts) mutants of Staphylococcus aureus with defective cell wall biosynthesis have been differentiated from other ts mutants by their ability to grow at the restrictive temperature (43 C) in the presence of 1 m NaCl. Under all conditions they possess normal colonial and cellular morphology at the level of resolution of the light microscope and are, therefore, not protoplasts. However, differences between mutant and wild-type cells can be seen by scanning electron microscopy. Many of the mutants contained concentrations of nucleotide precursors of peptidoglycan synthesis in excess of those present in wild-type cells, at both 30 and 43 C. The types of peptidoglycan precursors accumulated by six of the mutants have been determined, and specific enzymatic defects in three of these have been identified

Interpretation, translation and intercultural communication in refugee status determination procedures in the UK and France

This article explores the interplay between language and intercultural communication within refugee status determination procedures in the UK and France, using material taken from ethnographic research that involved a combination of participant observation, semi-structured interviews and documentary analysis in both countries over a two-year period (2007–2009). It is concerned, in particular, to examine the role played by interpreters in facilitating intercultural communication between asylum applicants and the different administrative and legal actors responsible for assessing or defending their claims. The first section provides an overview of refugee status determination procedures in the UK and France, introducing the main administrative and legal contexts of the asylum process within which interpreters operate in the two countries. The second section compares the organisation of interpreting services, codes of conduct for interpreters and institutional expectations about the nature of interpreters’ activity on the part of the relevant UK and French authorities. The third section then explores some of the practical dilemmas for interpreters and barriers to communication that exist in refugee status determination procedures in the two countries. The article concludes by emphasising the complex and active nature of the interpreter's role in UK and French refugee status determination procedures

Matter effects in the D0-D0bar system

We discuss the impact of matter effects in the D0-D0bar system. We show that such effects could, in principle, be measured, but that they cannot be used to probe the mass difference x_D or the lifetime difference y_D. This occurs because the mixing effects and the matter effects decouple at short times. We also comment briefly on the B systems.Comment: 6 pages, RevTe

Crystal structure of the catalytic fragment of murine poly(ADP-ribose) polymerase-2.

Poly(ADP-ribose) polymerase-1 (PARP-1) has become an important pharmacological target in the treatment of cancer due to its cellular role as a 'DNA-strand break sensor', which leads in part to resistance to some existing chemo- and radiological treatments. Inhibitors have now been developed which prevent PARP-1 from synthesizing poly(ADP-ribose) in response to DNA-breaks and potentiate the cytotoxicity of DNA damaging agents. However, with the recent discoveries of PARP-2, which has a similar DNA-damage dependent catalytic activity, and additional members containing the 'PARP catalytic' signature, the isoform selectivity and resultant pharmacological effects of existing inhibitors are brought into question. We present here the crystal structure of the catalytic fragment of murine PARP-2, at 2.8 A resolution, and compare this to the catalytic fragment of PARP-1, with an emphasis on providing a possible framework for rational drug design in order to develop future isoform-specific inhibitors

PRODUCTION OF IMMUNOLOGICAL TOLERANCE IN MICE AFTER REPEATED INJECTIONS OF DISRUPTED SPLEEN CELLS

1. Tolerance of male skin isografts has been regularly produced in female mice of the C57B1 strain sublines 1, 4, and 6 during adult life by repeated injection of completely disrupted spleen cells derived from male donors. The tolerant state is long-lasting since such grafts have remained in place more than 9 months. 2. Prolonged survival of homotransplants of skin has regularly been produced in DBA/2 mice during adult life by repeated injections of completely disrupted spleen cells from Balb/C donors. When injections of disrupted spleen cell material are continued over a sufficiently long period, permanent acceptance of the skin homografts may be obtained between these strains. 3. Immunological tolerance across even the strong H-2 histocompatibility barrier was obtained in the neonatal period and during adult life by repeated injection of disrupted spleen cell preparations. The tolerant state has been revealed by both mammary adenocarcinoma and skin homografting across this strong histocompatibility barrier. 4. In contradistinction to the tolerant state produced by injection of intact spleen cells in neonatal animals or during adult life or that produced by parabiotic union, the tolerance produced by repeated injection of disrupted spleen cell preparations cannot be transferred to syngenic neonatal mice with spleen cells of the tolerant animal. 5. The implications of these findings in transplantation biology and in consideration of the basic nature of tolerance are discussed