Topologica Defects and Corrections to the Nambu Action

The effective action of a (1+2)-dimensional defect is obtained as an expansion in powers of the thickness.Considering non-straight solutions as the zero order term, the corrections to the Nambu action are found to depend on the curvature scalar and on the gaussian curvature .Comment: UNB.FIS.FM-002/92, Marcos@FNAL, 12 pages, Late

Analyzing Powers for Deuteron-Induced Reactions Leading to Continuum Final States

This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

Capture-mark-recapture to estimate the number of missed articles for systematic reviews in surgery

Abstract BACKGROUND: Systematic reviews are an important knowledge synthesis tool, but with new literature available each day, reviewers must balance identifying all relevant literature against timely synthesis. METHODS: This study tested capture-mark-recapture (CMR), an ecology-based technique, to estimate the total number of articles in the literature identified in a systematic review of adult trauma care quality indicators. RESULTS: The systematic review included 40 articles identified from online searches and citation references. The CMR model suggested that 3 (95% confidence interval [CI]: 0 to 6) articles were missed and the database search provided 93% (one-sided 95% CI: R83%) of known articles for inclusion in the systematic review. The search order used for identifying the articles was optimal among the 24 that could have been used. CONCLUSIONS: The CMR technique can be used in systematic reviews in surgery to estimate the closeness to capturing the total body of literature for a specific topic. Ó 2013 Elsevier Inc. All rights reserved. Systematic reviews are increasingly used in surgery to synthesize knowledge so that evidence can inform clinical practice (eg, guideline development). Exhaustive searching in multiple large bibliographic databases is time consuming and resource intensive, but it needs to be efficient so the results are presented before the information becomes outdated. However, this is difficult because the amount of literature that exists on any given topic is unknown. Capture-mark-recapture (CMR) is a technique originating in ecology that has been applied to systematic reviews of randomized controlled trials of interventions in osteoporosis, gastroenterology, and hematology 1-3 to estimate The project was supported by a Synthesis Grant (KRS-91770) from the Canadian Institutes of Health Research. Dr. Stelfox is supported by a New Investigator Award from the Canadian Institutes of Health Research and a Population Health Investigator Award from Alberta Innovates. Funding sources had no role in the design, conduct, or reporting of this study and we are unaware of any conflicts of interest. None of the authors have financial or professional conflicts of interest that would influence the conduct or reporting of this study. Drs. Stelfox, Foster, and Goldsmith had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Presented at the Cochrane Canada Symposium May 9, 2012, Winnipeg, Canada. * Corresponding author. The American Journal of Surgery (2013) 206, 439-440 the number of articles in the literature. The technique has not been evaluated in observational studies or surgical studies. We therefore tested CMR to estimate the total number of articles in the literature identified in a systematic review of adult trauma care quality indicators. We performed a scoping review to identify quality indicators for evaluating trauma care 4 and subsequently systematically reviewed the evidence. 5 Horizon estimates (estimated total population of articles) were calculated for full text review and final inclusion using the 4 step CMR technique: (1) capture an initial sample from a population of interest (eg, catch fish in lake); (2) mark the elements in the sample (eg, tag the fish); (3) release the sample back into the population (eg, release tagged fish back into lake); and (4) resample the population (catch fish from same lake to see how many are tagged). Articles found in our 1st database (MEDLINE) were marked as being retrieved from that search and compared with articles retrieved through subsequent searches (eg, Embase was the 2nd database). Articles identified through bibliography reviews were attributed to the originating electronic database. Poisson regression models were used to calculate fitted estimates of the cell counts (number of articles missed) and estimate the total horizon of articles (SAS v 9.2; SAS, Cary, NC). The results of the horizon estimate are shown in We repeated the process for articles selected for inclusion in the systematic review. The final horizon estimate was 43 (40 to 46) articles, representing a difference of 3 (0 to 6) articles between the projected total literature and the number of articles captured (40 articles). Thus, selection of articles for inclusion in the systematic review represents the capture of 93% (87% to 100%) of the estimated pool of available articles. The search order used for identifying the articles was optimal among the 24 that could have been used. CMR is a technique that can be applied to estimate the total number of relevant articles for a given topic. This study demonstrates that CMR can be successfully used for systematic reviews of observational studies in surgery. Future systematic reviews may consider including horizon estimates as possible stopping rules (eg, search until 80% of articles captured) to identify when a sufficient literature search has been completed. CMR may help improve the completeness and efficiency of systematic reviews

Reaction Mechanism Implications of Deuteron Rainbow Scattering

This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

Measurements of X_2 and Other Results in the Analysis of d + 58-Ni Elastic Scattering

This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit

On the formation of sand ramps: A case study from the Mojave Desert

Sand ramps are dune-scale sedimentary accumulations found at mountain fronts and consist of a combination of aeolian sands and the deposits of other geomorphological processes associated with hillslope and fluvial activity. Their complexity and their construction by wind, water and mass movement means that sand ramps potentially hold a very rich store of palaeoenvironmental information. However, before this potential can be realised a full understanding of their formation is necessary. This paper aims to provide a better understanding of the principal factors influencing the development of sand ramps. It reviews the stratigraphic, chronometric and sedimentological evidence relating to the past development of sand ramps, focussing particularly on Soldier Mountain sand ramp in the Mojave Desert, as well as using observations of the modern movement of slope material to elucidate the formation of stone horizons within sand ramps. Findings show that sand ramps cannot easily be interpreted in terms of a simple model of fluctuating palaeoenvironmental phases from aeolian dominated to soil/fluvial dominated episodes. They accumulate quickly (perhaps in < 5 ka), probably in a single phase before becoming relict. Based on the evidence from Soldier Mountain, they appear strongly controlled by a ‘window of opportunity’ when sediment supply is plentiful and cease to develop when this sediment supply diminishes and/or the accommodation space is filled up. Contemporary observations of stone movement both on rock and sandy sloping surfaces in the Mojave region indicate movement rates in the order of 0.6 and 11 mm yr− 1, which is insufficiently fast to explain how stone horizons could have been moved across and been incorporated into sand ramps on multiple occasions. Stone horizons found within the aeolian sediments lack evidence for soil development and are interpreted as very short-term events in which small streams moved and splayed discontinuous stone horizons across the sand ramp surface before aeolian deposition resumed. Surface stone horizons may form by creep from mountain slope sources across sand ramps but require enhanced speed compared to measured rates of runoff creep. We propose the mechanism of fluvio-aeolian creep. Our study suggests that current models of alternating aeolian and colluvial deposition within sand ramps, their palaeoenvironmental significance and indeed how sand ramps are distinguished from other dune forms require amendment

Acid pH activation of the PmrA/PmrB two-component regulatory system of Salmonella enterica

Acid pH often triggers changes in gene expression. However, little is known about the identity of the gene products that sense fluctuations in extracytoplasmic pH. The Gram-negative pathogen Salmonella enterica serovar Typhimurium experiences a number of acidic environments both inside and outside animal hosts. Growth in mild acid (pH 5.8) promotes transcription of genes activated by the response regulator PmrA, but the signalling pathway(s) that mediates this response has thus far remained unexplored. Here we report that this activation requires both PmrA's cognate sensor kinase PmrB, which had been previously shown to respond to Fe(3+) and Al(3+), and PmrA's post-translational activator PmrD. Substitution of a conserved histidine or of either one of four conserved glutamic acid residues in the periplasmic domain of PmrB severely decreased or abolished the mild acid-promoted transcription of PmrA-activated genes. The PmrA/PmrB system controls lipopolysaccharide modifications mediating resistance to the antibiotic polymyxin B. Wild-type Salmonella grown at pH 5.8 were > 100 000-fold more resistant to polymyxin B than organisms grown at pH 7.7. Our results suggest that protonation of the PmrB periplasmic histidine and/or of the glutamic acid residues activate the PmrA protein, and that mild acid promotes cellular changes resulting in polymyxin B resistance

Features of the Analyzing Powers in Deuteron Elastic Scattering Near 80 MeV

This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

Salmonella and Campylobacter spp. in Northern Elephant Seals, California

Campylobacter and Salmonella spp. prevalence and antimicrobial drug sensitivity were determined in northern elephant seals that had not entered the water and seals that were stranded on the California coast. Stranded seals had a higher prevalence of pathogenic bacteria, possibly from terrestrial sources, which were more likely to be resistant