Energy Barriers for Flux Lines in 3 Dimensions

I determine the scaling behavior of the free energy barriers encountered by a flux line in moving through a three-dimensional random potential. A combination of numerical simulations and analytic arguments suggest that these barriers scale with the length of the line in the same way as the fluctuation in the free energy.Comment: 12 pages Latex, 4 postscript figures tarred, compressed, uuencoded using `uufiles', coming with a separate fil

Permafrost nitrous oxide emissions observed on a landscape scale using the airborne eddy-covariance method

The microbial by-product nitrous oxide (N2O), a potent greenhouse gas and ozone depleting substance, has conventionally been assumed to have minimal emissions in permafrost regions. This assumption has been questioned by recent in situ studies which have demonstrated that some geologic features in permafrost may, in fact, have elevated emissions comparable to those of tropical soils. However, these recent studies, along with every known in situ study focused on permafrost N2O fluxes, have used chambers to examine small areas (&lt;50&thinsp;m2). In late August 2013, we used the airborne eddy-covariance technique to make in situ N2O flux measurements over the North Slope of Alaska from a low-flying aircraft spanning a much larger area: around 310&thinsp;km2. We observed large variability of N2O fluxes with many areas exhibiting negligible emissions. Still, the daily mean averaged over our flight campaign was 3.8 (2.2–4.7)&thinsp;mg&thinsp;N2O&thinsp;m−2&thinsp;d−1 with the 90&thinsp;% confidence interval shown in parentheses. If these measurements are representative of the whole month, then the permafrost areas we observed emitted a total of around 0.04–0.09&thinsp;g&thinsp;m−2 for August, which is comparable to what is typically assumed to be the upper limit of yearly emissions for these regions.</p

February 1967 Conference Issue

Massachusetts Turf and Lawn Grass CouncilBetter Turf Through Research and Educatio

The association of cold weather and all-cause and cause-specific mortality in the island of Ireland between 1984 and 2007

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background This study aimed to assess the relationship between cold temperature and daily mortality in the Republic of Ireland (ROI) and Northern Ireland (NI), and to explore any differences in the population responses between the two jurisdictions. Methods A time-stratified case-crossover approach was used to examine this relationship in two adult national populations, between 1984 and 2007. Daily mortality risk was examined in association with exposure to daily maximum temperatures on the same day and up to 6 weeks preceding death, during the winter (December-February) and cold period (October-March), using distributed lag models. Model stratification by age and gender assessed for modification of the cold weather-mortality relationship. Results In the ROI, the impact of cold weather in winter persisted up to 35 days, with a cumulative mortality increase for all-causes of 6.4% (95%CI=4.8%-7.9%) in relation to every 1oC drop in daily maximum temperature, similar increases for cardiovascular disease (CVD) and stroke, and twice as much for respiratory causes. In NI, these associations were less pronounced for CVD causes, and overall extended up to 28 days. Effects of cold weather on mortality increased with age in both jurisdictions, and some suggestive gender differences were observed. Conclusions The study findings indicated strong cold weather-mortality associations in the island of Ireland; these effects were less persistent, and for CVD mortality, smaller in NI than in the ROI. Together with suggestive differences in associations by age and gender between the two Irish jurisdictions, the findings suggest potential contribution of underlying societal differences, and require further exploration. The evidence provided here will hope to contribute to the current efforts to modify fuel policy and reduce winter mortality in Ireland

Dextral and sinistral Amphidromus inversus (Gastropoda: Pulmonata: Camaenidae) produce dextral sperm

Coiling direction in pulmonate gastropods is determined by a single gene via a maternal effect, which causes cytoskeletal dynamics in the early embryo of dextral gastropods to be the mirror image of the same in sinistral ones. We note that pulmonate gastropod spermatids also go through a helical twisting during their maturation. Moreover, we suspect that the coiling direction of the helical elements of the spermatozoa may affect their behaviour in the female reproductive tract, giving rise to the possibility that sperm chirality plays a role in the maintenance of whole-body chiral dimorphism in the tropical arboreal gastropod Amphidromus inversus (Müller, 1774). For these reasons, we investigated whether there is a relationship between a gastropod’s body chirality and the chirality of the spermatozoa it produces. We found that spermatozoa in A. inversus are always dextrally coiled, regardless of the coiling direction of the animal itself. However, a partial review of the literature on sperm morphology in the Pulmonata revealed that chiral dimorphism does exist in certain species, apparently without any relationship with the coiling direction of the body. Though our study shows that body and sperm chirality follows independent developmental pathways, it gives rise to several questions that may be relevant to the understanding of the chirality of spermatid ultrastructure and spermatozoan motility and sexual selection

Adaptation of Autocatalytic Fluctuations to Diffusive Noise

Evolution of a system of diffusing and proliferating mortal reactants is analyzed in the presence of randomly moving catalysts. While the continuum description of the problem predicts reactant extinction as the average growth rate becomes negative, growth rate fluctuations induced by the discrete nature of the agents are shown to allow for an active phase, where reactants proliferate as their spatial configuration adapts to the fluctuations of the catalysts density. The model is explored by employing field theoretical techniques, numerical simulations and strong coupling analysis. For d<=2, the system is shown to exhibits an active phase at any growth rate, while for d>2 a kinetic phase transition is predicted. The applicability of this model as a prototype for a host of phenomena which exhibit self organization is discussed.Comment: 6 pages 6 figur

Complete Genome Sequence of Geobacter sp. Strain FeAm09, a Moderately Acidophilic Soil Bacterium

A moderately acidophilic Geobacter sp. strain, FeAm09, was isolated from forest soil. The complete genome sequence is 4,099,068 bp with an average GC content of 61.1%. No plasmids were detected. The genome contains a total of 3,843 genes and 3,608 protein-coding genes, including genes supporting iron and nitrogen biogeochemical cycling