(Un)frozen spaces: Exploring the role of sea ice in the marine socio-legal spaces of the Bering and Beaufort Seas

Sea ice is a dynamic physical element of the greater Arctic marine system, one that has myriad connections to human systems on a variety of spatial and temporal scales. Changes to the spatial extent of sea ice simultaneously permits and endangers maritime operations, as well as impacts current debates over maritime boundaries, presenting an interesting challenge for international law. Sea ice is not a stationary object; it moves through time and space in response to the physical forces of wind, ocean currents, and heating. It has a tangible, material and substantive role in contestations over territory, resources and marine boundaries in both the Beaufort and Bering Seas. We suggest here that sea ice’s material nature in these marine regions continuously challenges stationary conceptions of law in complex and sometimes contradictory ways. Building on recent work on the human geographies of sea ice, the dynamic field of legal geography and recent contributions in ocean-space geography, we outline how the dynamism of sea ice could influence notions of boundary, resources and climate change in ocean-spaces of the greater Arctic region

Positive cross-correlations induced by ferromagnetic contacts

Due to the Fermionic nature of carriers, correlations between electric currents flowing through two different contacts attached to a conductor present a negative sign. Possibility for positive cross-correlations has been demonstrated in hybrid normal/superconductor structures under certain conditions. In this paper we show that positive cross-correlations can be induced, if not already present, in such structures by employing ferromagnetic leads with magnetizations aligned anti-parallel to each other. We consider three-terminal hybrid structures and calculate the mean-square correlations of current fluctuations as a function of the bias voltage at finite temperature.Comment: 6 pages, 5 figures; accepted version by PRB, figures replace

The origins of the Irish Travellers and the genetic structure of Ireland

Ireland's unique and well-documented history provides insight into the formation and origins of population subdivisions. Of particular interest, is the controversial ethnogenesis of an itinerant population of Ireland: the Travellers. The objectives of this study were: (1) to determine the genetic affinity of the Travellers to the general Irish population based on gene frequency data, subdivided by county, and (2) to explore the relationship between subpopulations of Ireland, given its turbulent history. The gene frequencies of standard genetic markers collected from populations residing in counties of Ireland and the Travellers were calculated and analysed using several multivariate methods. First, a relationship (R) matrix was used to ascertain the scaled variance-covariance matrix of population similarity. Second, mean per locus heterozygosity (H) was regressed on distance of the region from the gene frequency centroid (r(ii)). The results of this study include: (1) the confirmation of Crawford's (1975, in Biosocial Interrelations in Population Adaptations, E. S. Watts et al. (eds), pp. 93-103) conclusions concerning the origins and genetic affinity of the Travellers; (2) based on several multivariate analyses, the major influence on population structure was unique historical events; and (3) Relethford and Crawford's (1995, American Journal of Physical Anthropology, 96, 25-38) hypothesis concerning the distinctiveness of the midland counties was verified by this study

Spin-Flip Noise in a Multi-Terminal Spin-Valve

We study shot noise and cross correlations in a four terminal spin-valve geometry using a Boltzmann-Langevin approach. The Fano factor (shot noise to current ratio) depends on the magnetic configuration of the leads and the spin-flip processes in the normal metal. In a four-terminal geometry, spin-flip processes are particular prominent in the cross correlations between terminals with opposite magnetization.Comment: 4 pages, 3 figure

Learning to Look With One Eye: The Use of Head Turn by Normals and Strabismics

AbstractWhen asked to look through a tube, young children (normal, strabismic, monocularly enucleated) place it between the eyes, while older children turn the head or shut one eye. We videotaped 174 children (normals and strabismics, 2–17 yr of age) and 16 normal adults to find out when and why head turn occurs. In learning to look with one eye, children progressed through a sequence of four responses, categorized by age or amount of head turn. Binocular children use head turn apparently to avoid diplopia, then, most learn to shut one eye. Adults, forced to use the “non-preferred” eye, revert to turning the head. Copyright © 1996 Elsevier Science Ltd

Shot Noise in Nanoscale Conductors From First Principles

We describe a field-theoretic approach to calculate quantum shot noise in nanoscale conductors from first principles. Our starting point is the second-quantization field operator to calculate shot noise in terms of single quasi-particle wavefunctions obtained self-consistently within density functional theory. The approach is valid in both linear and nonlinear response and is particularly suitable in studying shot noise in atomic-scale conductors. As an example we study shot noise in Si atomic wires between metal electrodes. We find that shot noise is strongly nonlinear as a function of bias and it is enhanced for one- and two-Si wires due to the large contribution from the metal electrodes. For longer wires it shows an oscillatory behavior for even and odd number of atoms with opposite trend with respect to the conductance, indicating that current fluctuations persist with increasing wire length.Comment: 4 pages, 4 figure

Seismic issues at the Paducah Gaseous Diffusion Plant

A seismic expert workshop was held at the Paducah Gaseous Diffusion Plant (PGDP) on March 13--15, 1989. the PGDP is operated by Martin Marietta Energy Systems, Inc. for the United States Department of Energy (DOE). During the last twenty years the design criteria for natural phenomenon hazards has steadily become more demanding at all of the DOE Oak Ridge Operations (ORO) sites. The purpose of the two-day workshop was to review the seismic vulnerability issues of the PGDP facilities. Participants to the workshop included recognized experts in the fields of seismic engineering, seismology and geosciences, and probabilistic analysis, along with engineers and other personnel from Energy Systems. A complete list of the workshop participants is included in the front of this report. 29 refs

Macro and micro diversity of Clostridium difficile isolates from diverse sources and geographical locations.

Clostridium difficile has emerged rapidly as the leading cause of antibiotic-associated diarrheal disease, with the temporal and geographical appearance of dominant PCR ribotypes such as 017, 027 and 078. Despite this continued threat, we have a poor understanding of how or why particular variants emerge and the sources of strains that dominate different human populations. We have undertaken a breadth genotyping study using multilocus sequence typing (MLST) analysis of 385 C. difficile strains from diverse sources by host (human, animal and food), geographical locations (North America, Europe and Australia) and PCR ribotypes. Results identified 18 novel sequence types (STs) and 3 new allele sequences and confirmed the presence of five distinct clonal lineages generally associated with outbreaks of C. difficile infection in humans. Strains of animal and food origin were found of both ST-1 and ST-11 that are frequently associated with human disease. An in depth MLST analysis of the evolutionary distant ST-11/PCR ribotype 078 clonal lineage revealed that ST-11 can be found in alternative but closely related PCR ribotypes and PCR ribotype 078 alleles contain mutations generating novel STs. PCR ribotype 027 and 017 lineages may consist of two divergent subclades. Furthermore evidence of microdiversity was present within the heterogeneous clade 1. This study helps to define the evolutionary origin of dominant C. difficile lineages and demonstrates that C. difficile is continuing to evolve in concert with human activity

Dynamics of Fermionic Four-Wave Mixing

We study the dynamics of a beam of fermions diffracted off a density grating formed by fermionic atoms in the limit of a large grating. An exact description of the system in terms of particle-hole operators is developed. We use a combination of analytical and numerical methods to quantitatively explore the Raman-Nath and the Bragg regimes of diffraction. We discuss the limits in diffraction efficiency resulting from the dephasing of the grating due the distribution of energy states occupied by the fermions. We propose several methods to overcome these limits, including the novel technique of ``atom echoes''.Comment: 8 pages, 7 figure

HiggsBounds: Confronting Arbitrary Higgs Sectors with Exclusion Bounds from LEP and the Tevatron

HiggsBounds is a computer code that tests theoretical predictions of models with arbitrary Higgs sectors against the exclusion bounds obtained from the Higgs searches at LEP and the Tevatron. The included experimental information comprises exclusion bounds at 95% C.L. on topological cross sections. In order to determine which search topology has the highest exclusion power, the program also includes, for each topology, information from the experiments on the expected exclusion bound, which would have been observed in case of a pure background distribution. Using the predictions of the desired model provided by the user as input, HiggsBounds determines the most sensitive channel and tests whether the considered parameter point is excluded at the 95% C.L. HiggsBounds is available as a Fortran 77 and Fortran 90 code. The code can be invoked as a command line version, a subroutine version and an online version. Examples of exclusion bounds obtained with HiggsBounds are discussed for the Standard Model, for a model with a fourth generation of quarks and leptons and for the Minimal Supersymmetric Standard Model with and without CP-violation. The experimental information on the exclusion bounds currently implemented in HiggsBounds will be updated as new results from the Higgs searches become available.Comment: 64 pages, 15 tables, 8 figures; three typos which made it to the published version corrected; the code (currently version 3.0.0beta including LHC Higgs search results) is available via: http://projects.hepforge.org/higgsbounds