Inelastic neutron and x-ray scattering as probes of the sign structure of the Fe-pnictide superconducting gap

Neutron spin-flip scattering observations of a resonance in the superconducting state is often taken as evidence of an unconventional superconducting state in which the gap changes sign $\Delta(k+Q)=-\Delta(k)$ for momentum transfers $Q$ which play an important role in the pairing. Recently questions regarding this identification for the Fe-pnictide superconductors have been raised and it has been suggested that $\Delta(k+Q)=\Delta(k)$. Here we propose that inelastic neutron or x-ray scattering measurements of the spectral weight of a phonon of momentum $Q$ can distinguish between these two pairing scenarios.Comment: 4 pages, 4 figure

Sediment release of dissolved organic matter to the oxygen minimum zone off Peru

The eastern tropical South Pacific (ETSP) represents one of the most productive areas in the ocean that is characterized by a pronounced oxygen minimum zone (OMZ). Particulate organic matter (POM) that sinks out of the euphotic zone is supplied to the anoxic sediments and utilized by microbial communities. The degradation of POM is associated with dissolved organic matter (DOM) production and reworking. The release of recalcitrant DOM to the overlying waters may represent an important organic matter escape mechanism from remineralization within sediments but received little attention in OMZ regions so far. Here, we combine measurements of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) with DOM optical properties in the form of chromophoric (CDOM) and fluorescent (FDOM) DOM from pore waters and near-bottom waters of the ETSP off Peru. We evaluate diffusion–driven fluxes and net in situ fluxes of DOC and DON in order to investigate processes affecting DOM cycling at the sediment–water interface along a transect 12° S. To our knowledge, these are the first data for sediment release of DON and pore water CDOM and FDOM for the ETSP off Peru. Pore-water DOC and DON accumulated with increasing sediment depth, suggesting an imbalance between DOM production and remineralization within sediments. High DON accumulation resulted in very low pore water DOC / DON ratios (> 1) which could be caused by either an "imbalance" in DOC and DON remineralization, or to the presence of an additional nitrogen source. Diffusion driven fluxes of DOC and DON exhibited high spatial variability. They varied from 0.2–0.1 mmol m−2 d−1 to 2.52–1.3 mmol m−2 d−1 and from −0.042–0.02 mmol m−2 d−1 to 3.32–1.7 mmol m−2 d−1, respectively. Generally low net in situ DOC and DON fluxes as well as steepening of spectral slope (S) of CDOM and accumulation of humic-like FDOM at the near-bottom waters over time indicated active microbial DOM utilization at the sediment–water interface, potentially stimulated by nitrate (NO3−) and nitrite (NO2−). The microbial DOC utilization rates, estimated in our study, may be sufficient to support denitrification rates of 0.2–1.4 mmol m−2 d−1, suggesting that sediment release of DOM contributes substantially to nitrogen loss processes in the ETSP off Peru

Sediment release of dissolved organic matter in the oxygen minimum zone off Peru

In combination to sluggish ventilation by ocean currents, the nutrient upwelling and high surface productivity, followed by organic matter remineralization, leads to a pronounced oxygen minimum zone (OMZ) in the eastern tropical South Pacific (ETSP). There, oxygen concentrations drop below 1 �mol/kg at a water depth <80 m. The high productivity results in the supply of organic matter (OM) to the anoxic sediments and its utilization by heterotrophic communities. The microbial utilization of OM under anoxia leads to nitrogen loss processes, and an accumulation of sulphide and methane. The proximity of the OMZ to the ocean surface in the ETSP may lead to an active outgassing of climate relevant products of the anoxic OM remineralization. The degradation of OM in sediments is associated with production of dissolved organic matter (DOM) from organic particles (POM) that is further remineralized into inorganic nutrients and dissolved inorganic carbon, which then can be released back to the water column, fuelling productivity. Part of the DOM pool may be released to the overlying water column and serve as ligands for micronutrients, such as iron, or provide an additional substrate for microbial communities to respire, affecting overlying water column biogeochemistry. Despite the potential relevance for biogeochemical processes, the quality of the DOM in the pore waters that may be released to the overlying water column has been barely studied in the ETSP off Peru. High spatial resolution measurements of DOM fluorescence (FDOM) during the research cruise M93 (Feb-March 2013) indicated elevated intensities near the sediments in the ETSP off Peru. Those intensities were interpreted as a sediment release of DOM, the quantification of dissolved organic carbon (DOC) flux, however, was not possible at the time. To estimate DOM fluxes and DOM quality, DOC and DOM samples were collected from the sediment pore waters and from benthic incubation chambers from six stations along the 12°S transect in the Peruvian upwelling in 2017 (cruises M136, M137). Samples were collected using a multiple-corer and by Biogeochemical Observatories, respectively. Here, we evaluate DOC fluxes from the sediments and relate them to the measurements of FDOM. We evaluate the quality of DOM by Excitation Emission spectroscopy, followed by parallel factor analysis. The possible implications of the DOM release for water column biogeochemistry are discussed

The Baum-Connes Conjecture via Localisation of Categories

We redefine the Baum-Connes assembly map using simplicial approximation in the equivariant Kasparov category. This new interpretation is ideal for studying functorial properties and gives analogues of the assembly maps for all equivariant homology theories, not just for the K-theory of the crossed product. We extend many of the known techniques for proving the Baum-Connes conjecture to this more general setting

European Sustainable Urbanisation through port city Regeneration - Targeted Analysis Final Report

ENSURE (European Sustainable Urbanisation through port city Regeneration) is a targeted analysis aimed at providing better insights into the potential regional impacts of port city regeneration and a better understanding of the appropriate methods and tools. The research involved a comprehensive literature review, a pan-European desktop analysis of port city regeneration in small and medium-sized cities and in-depth case studies in four stakeholder cities, as well as a series of workshops and conferences. The research shows that a main driver for the development of ports in Europe was the industrial revolution and the continued industrial growth until the mid-20th century. Similarly, a retreat from the waterfront became evident during the last part of the century as the deindustrialisation gathered pace, driven by increased global competition, spatial relocation of industry, and technological changes in both industry and transport. Another key aspect was the collapse of socialism in eastern Europe. Many cities in this part of Europe had active ports that became militarised during the Soviet era and later de-militarised as these states transitioned to a new political-economic structure. The desktop research indicated that about a third of small and medium-sized European port cities (48 of 144) show no evidence of regeneration. Some of these cities may be thriving and have no need for regeneration, but there is likely to be a significant latent potential across the European territory

Leveraging icebreaking tasks to facilitate uptake of voice communication in multiplayer games

Voice Communication (VC) is widely employed by developers as an essential component of online games. Typically, it is assumed that communications through this mechanism will be helpful and enjoyable, but existing literature suggests that the entry into VC can be problematic. In this paper, we present a study that attempts to mitigate player discomfort when first engaging with VC with strangers, through the use of traditional icebreaking tasks. We integrate these into the game RET, an online cooperative first person shooter which requires effective communication for players to succeed. An online user study with 18 participants suggests that icebreaking tasks can contribute to a positive VC experience, but their inclusion also creates further issues to be considered for successful integration

Deep imaging of Q2112+059: A bright host galaxy but no DLA absorber

In a ongoing programme aimed at studying galaxy counterparts of Damped Ly-alpha Absorbers (DLAs) we have obtained high resolution deep I-band imaging data of the field around the z_em = 0.457 BAL QSO Q2112+059. In the literature this QSO is listed to have a candidate DLA at z_abs = 0.2039 along the line of sight. After subtraction of the QSO Point Spread Function (PSF) we detect a galaxy centred on the position of Q2112+059. To help answer whether this galaxy is the DLA or the QSO host galaxy we retrieved a GHRS spectrum of Q2112+059 from the HST-archive. This spectrum shows that there is no Ly-alpha absorption line at z_abs = 0.2039. This fact in combination with the perfect alignment on the sky of the galaxy and Q2112+059 lead us to the conclusion that the galaxy must be the host galaxy of Q2112+059. The host galaxy of Q2112+059 is bright (M_I^obs = -23.6), and has a radial profile well fitted by a {\it modified Hubble + de Vaucouleurs} profile with R_c = 0.5 kpc and R_e = 3.6 kpc. Our results are well in line with the conclusion of earlier work done at lower redshifts, that bright low redshift QSOs preferentially reside in luminous, elliptical galaxies. The host of Q2112+059 is however, despite it's brightness, very compact when compared to early type galaxies at lower redshifts.Comment: 6 pages, 5 figures. Accepted for publication in A&

The Dixmier property and tracial states for C*-algebras

A.T. was partially supported by an NSERC Postdoctoral Fellowship and through the EPSRC grant EP/N00874X/1. Acknowledgements We are grateful to Luis Santiago for helpful discussions at an early stage of this investigation. We would also like to thank the referee for providing helpful comments, which have led to a number of improvements.Peer reviewedPublisher PD

Task force on immigration and higher education in Central Massachusetts

In August 2007, the Colleges of Worcester Consortium, Inc. created a task force to examine the issue of immigration and higher education in Central Massachusetts. It has become increasingly clear from recent demographic and economic studies and projections that the population in the northeast, and certainly in Central Massachusetts, is showing minimal growth. There is evidence that a decline in the “native-born” population is caused by significant out-migration due to a number of factors, including the high cost of living, limited career opportunities and a declining birth rate. The limited population growth that is evident is due primarily to the recent influx of immigrants to this area, with the most significant numbers in Worcester coming from Ghana, Brazil, the Dominican Republic, Kenya, El Salvador, Albania and Liberia. It is also clear that the area’s economy is becoming more knowledge-based with an increasing percentage of all new jobs requiring some form of postsecondary education. According to the 2007 Massachusetts Department of Workforce Development’s Job Vacancy Survey, 38 percent of current job vacancies in Massachusetts require an associate’s degree or higher. This represents an increase from 30 percent in 2003. Consequently, the level of education that the immigrant population attains is of vital importance to everyone—not only to immigrant students and their families but also to the economic well-being of the entire region. The Task Force was charged with researching the barriers to higher education faced by this new wave of immigrants and suggesting recommendations to address those barriers. The 36-member Task Force was made up of representatives from Consortium member institutions; federal, state and local governments; community and faithbased organizations; the Worcester Public Schools; the Massachusetts Board of Higher Education; and the Massachusetts Immigrant and Refugee Advocacy (MIRA) Coalition. Meetings were held over six months, during which the Task Force identified three main barriers faced by immigrant communities in accessing higher education, and sub-committees were created to work on each of these. Speakers were invited to present on topics of interest. Two public hearings were held, the first of which was conducted at Worcester State College in October. It attracted community representatives, as well as college and high school faculty and administrators. The second hearing, held at the downtown branch of Quinsigamond Community College (QCC) in December, was attended by immigrants (English for Speakers of Other Languages – ESOL and GED) students as well as QCC staff.Published versio

You are what you eat? Vegetarianism, health and identity

This paper examines the views of ‘health vegetarians’ through a qualitative study of an online vegetarian message board. The researcher participated in discussions on the board, gathered responses to questions from 33 participants, and conducted follow-up e-mail interviews with 18 of these participants. Respondents were predominantly from the United States, Canada and the UK. Seventy per cent were female, and ages ranged from 14 to 53 years, with a median of 26 years. These data are interrogated within a theoretical framework that asks, ‘what can a vegetarian body do?’ and explores the physical, psychic, social and conceptual relations of participants. This provides insights into the identities of participants, and how diet and identity interact. It is concluded that vegetarianism is both a diet and a bodily practice with consequences for identity formation and stabilisation