Plans for a Neutron EDM Experiment at SNS

The electric dipole moment of the neutron, leptons, and atoms provide a unique window to Physics Beyond the Standard Model. We are currently developing a new neutron EDM experiment (the nEDM Experiment). This experiment, which will be run at the 8.9 A Neutron Line at the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory, will search for the neutron EDM with a sensitivity two orders of magnitude better than the present limit. In this paper, the motivation for the experiment, the experimental method, and the present status of the experiment are discussed.Comment: 9 Pages, 4 Figures, submitted to the proceedings of the Second Meeting of the APS Topical Group on Hadronic Physics, Nashville, TN, October 22-24, 200

A network to understand the changing socio-ecology of the southern African woodlands (SEOSAW): Challenges, benefits, and methods

Societal Impact StatementThe sustainable management of the southern African woodlands is closely linked to the livelihoods of over 150 M people. Findings from the Socio-Ecological Observatory for the Southern African Woodlands (SEOSAW) will underpin the sustainability of two of the largest industries on the continent: woodfuels and timber. SEOSAW will also improve our understanding of how human use shapes the biogeography and functioning of these ecosystems.SummaryHere we describe a new network of researchers and long-term, in situ, measurements that will characterize the changing socio-ecology of the woodlands of southern Africa. These woodlands encompass the largest savanna in the world, but are chronically understudied, with few long-term measurements. A network of permanent sample plots (PSPs) is required to: (a) address management issues, particularly related to sustainable harvesting for energy and timber; (b) understand how the woodlands are responding to a range of global and local drivers, such as climate change, CO2 fertilization, and harvesting; and (c) answer basic questions about biogeography, ecosystem function, and the role humans play in shaping the ecology of the region. We draw on other successful networks of PSPs and adapt their methods to the specific challenges of working in southern African woodlands. In particular we suggest divergences from established forest monitoring protocols that are needed to (a) adapt to a high level of ecosystem structural diversity (from open savanna to dry forest); (b) quantify the chronic disturbances by people, fire, and herbivores; (c) quantify the diversity and function of the understory of grasses, forbs, and shrubs; (d) understand the life histories of resprouting trees; and (e) conduct work in highly utilized, human-dominated landscapes. We conclude by discussing how the SEOSAW network will integrate with remote sensing and modeling approaches. Throughout, we highlight the challenges inherent to integrating work by forest and savanna ecologists, and the wide range of skills needed to fully understand the socio-ecology of the southern African woodlands

Development of methods for the genetic manipulation of Flavobacterium columnare

<p>Abstract</p> <p>Background</p> <p><it>Flavobacterium columnare </it>is the causative agent of columnaris disease, a disease affecting many freshwater fish species. Methods for the genetic manipulation for some of the species within the <it>Bacteroidetes</it>, including members of the genus <it>Flavobacterium</it>, have been described, but these methods were not adapted to work with <it>F. columnare</it>.</p> <p>Results</p> <p>As a first step toward developing a robust set of genetic tools for <it>F. columnare</it>, a protocol was developed to introduce the <it>E. coli </it>– <it>Flavobacterium </it>shuttle vector pCP29 into <it>F. columnare </it>strain C#2 by conjugal mating at an efficiency of 1.5 × 10^-3antibiotic-resistant transconjugants per recipient cell. Eight of eleven <it>F. columnare </it>strains tested were able to receive pCP29 using the protocol. pCP29 contains the <it>cfxA </it>and <it>ermF </it>genes, conferring both cefoxitin and erythromycin resistance to recipient cells. Selection for pCP29 introduction into <it>F. columnare </it>was dependent on <it>cfxA</it>, as <it>ermF </it>was found not to provide strong resistance to erythromycin. This is in contrast to other <it>Flavobacterium </it>species where <it>ermF</it>-based erythromycin resistance is strong. The green fluorescent protein gene (<it>gfp</it>) was introduced into <it>F. columnare </it>strains under the control of two different native <it>Flavobacterium </it>promoters, demonstrating the potential of this reporter system for the study of gene expression. The transposon Tn<it>4351 </it>was successfully introduced into <it>F. columnare</it>, but the method was dependent on selecting for erythromycin resistance. To work, low concentrations of antibiotic (1 μg ml^-1) were used, and high levels of background growth occurred. These results demonstrate that Tn<it>4351 </it>functions in <it>F. columnare </it>but that it is not an effective mutagenesis tool due to its dependence on erythromycin selection. Attempts to generate mutants via homologous recombination met with limited success, suggesting that RecA dependent homologous recombination is rare in <it>F. columnare</it>.</p> <p>Conclusion</p> <p>The conjugation protocol developed as part of this study represents a significant first step towards the development of a robust set of genetic tools for the manipulation of <it>F. columnare</it>. The availability of this protocol will facilitate studies aimed at developing a deeper understanding of the virulence mechanisms of this important pathogen.</p

The SCUBA 8-mJy survey - I: Sub-millimetre maps, sources and number counts

We present maps, source lists, and number counts from the largest, unbiassed, extragalactic sub-mm survey so far undertaken with the SCUBA camera on the JCMT. Our maps cover 260 sq. arcmin, to a noise level S(850)=2.5 mJy/beam. We have reduced the data using both SURF, and our own pipeline which produces zero-footprint maps and noise images. The uncorrelated noise maps produced by the latter approach have allowed application of a maximum-likelihood method to measure the statistical significance of each peak, leading to properly quantified flux-density errors for all potential sources. We detect 19 sources with S/N > 4, 38 with S/N > 3.5, and 72 with S/N > 3. To assess completeness and the impact of source confusion we have applied our source extraction algorithm to a series of simulated images. The result is a new estimate of the sub-mm source counts in the flux-density range S(850)=5-15mJy, which we compare with other estimates, and with model predictions. Our estimate of the cumulative source count at S(850) > 8 mJy is 320 (+80,-100) per square degree. Assuming that the majority of sources have z > 1.5, the co-moving number density of high-z galaxies forming stars at a rate >1000 solar masses per year is 10^-5 per Mpc^3, with only a weak dependence on the precise redshift distribution. This number density corresponds to that of massive ellipticals with L > 3-4 L* at low redshift and is also the same as the co-moving number density of comparably massive, passively-evolving objects in the redshift band 1<z<2 inferred from recent surveys of extremely red objects. Thus the bright sub-mm sources can plausibly account for the formation of all present-day massive ellipticals. Improved z constraints, and a proper measurement of sub-mm clustering can refine or refute this picture.Comment: Minor revisions. 27 pages, 13 figures. Higher resolution versions of Figs 5,6,7 and 8 are available from the autho

Development of Methods for the Genetic Manipulation of \u3cem\u3eFlavobacterium columnare\u3c/em\u3e

Background: Flavobacterium columnare is the causative agent of columnaris disease, a disease affecting many freshwater fish species. Methods for the genetic manipulation for some of the species within the Bacteroidetes, including members of the genus Flavobacterium, have been described, but these methods were not adapted to work with F. columnare. Results: As a first step toward developing a robust set of genetic tools for F. columnare, a protocol was developed to introduce the E. coli – Flavobacterium shuttle vector pCP29 into F. columnare strain C#2 by conjugal mating at an efficiency of 1.5 × 10-3 antibiotic-resistant transconjugants per recipient cell. Eight of eleven F. columnare strains tested were able to receive pCP29 using the protocol. pCP29 contains the cfxA and ermF genes, conferring both cefoxitin and erythromycin resistance to recipient cells. Selection for pCP29 introduction into F. columnare was dependent on cfxA, as ermF was found not to provide strong resistance to erythromycin. This is in contrast to other Flavobacterium species where ermF-based erythromycin resistance is strong. The green fluorescent protein gene (gfp) was introduced into F. columnare strains under the control of two different native Flavobacterium promoters, demonstrating the potential of this reporter system for the study of gene expression. The transposon Tn4351 was successfully introduced into F. columnare, but the method was dependent on selecting for erythromycin resistance. To work, low concentrations of antibiotic (1 μg ml-1) were used, and high levels of background growth occurred. These results demonstrate that Tn4351 functions in F. columnare but that it is not an effective mutagenesis tool due to its dependence on erythromycin selection. Attempts to generate mutants via homologous recombination met with limited success, suggesting that RecA dependent homologous recombination is rare in F. columnare. Conclusion: The conjugation protocol developed as part of this study represents a significant first step towards the development of a robust set of genetic tools for the manipulation of F. columnare. The availability of this protocol will facilitate studies aimed at developing a deeper understanding of the virulence mechanisms of this important pathogen

Algal food and fuel coproduction can mitigate greenhouse gas emissions while improving land and water-use efficiency

The goals of ensuring energy, water, food, and climate security can often conflict.Microalgae (algae) are being pursued as a feedstockfor both food and fuels—primarily due to algae’s high areal yield and ability to grow on non-arable land, thus avoiding common bioenergy-food tradeoffs. However, algal cultivation requires significant energy inputs that may limit potential emission reductions.We examine the tradeoffs associated with producing fuel andfood from algae at the energy–food–water–climate nexus.We use the GCAM integrated assessment model to demonstrate that algalfood production can promote reductions in land-use change emissions through the offset of conventional agriculture. However,fuel production, either via co-production of algal food and fuel or complete biomass conversion to fuel, is necessary to ensure long-term emission reductions, due to the high energy costs of cultivation. Cultivation of salt– water algae for food products may lead to substantial freshwater savings; but, nutrients for algae cultivation will need to be sourced from waste streams to ensure sustainability. By reducing the land demand of food production, while simultaneously enhancingfood and energy security, algae can further enable the development of terrestrial bioenergy technologies including those utilizing carbon capture and storage. Our results demonstrate that large-scale algae research and commercialization efforts should focus on developing both food and energy products to achieve environmental goals.https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114006/metaPublished versio