9,939 research outputs found

    Experiencing space–time: the stretched lifeworlds of migrant workers in India

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    In the relatively rare instances when the spatialities of temporary migrant work, workers’ journeys, and labour-market negotiations have been the subject of scholarly attention, there has been little work that integrates time into the analysis. Building on a case study of low-paid and insecure migrant manual workers in the context of rapid economic growth in India, we examine both material and subjective dimensions of these workers’ spatiotemporal experiences. What does it mean to live life stretched out, multiplyattached to places across national space? What kinds of place attachments emerge for people temporarily sojourning in, rather than moving to, new places to reside and work? Our analysis of the spatiotemporalities of migrant workers’ experiences in India suggests that, over time, this group of workers use their own agency to seek to avoid the experience of humiliation and indignity in employment relations. Like David Harvey, we argue that money needs to be integrated into such analysis, along with space and time. The paper sheds light on processes of exclusion, inequality and diff erentiation, unequal power geometries, and social topographies that contrast with neoliberalist narratives of ‘Indian shining

    Imaging the Cosmic Matter Distribution using Gravitational Lensing of Pregalactic HI

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    21-cm emission from neutral hydrogen during and before the epoch of cosmic reionisation is gravitationally lensed by material at all lower redshifts. Low-frequency radio observations of this emission can be used to reconstruct the projected mass distribution of foreground material, both light and dark. We compare the potential imaging capabilities of such 21-cm lensing with those of future galaxy lensing surveys. We use the Millennium Simulation to simulate large-area maps of the lensing convergence with the noise, resolution and redshift-weighting achievable with a variety of idealised observation programmes. We find that the signal-to-noise of 21-cm lens maps can far exceed that of any map made using galaxy lensing. If the irreducible noise limit can be reached with a sufficiently large radio telescope, the projected convergence map provides a high-fidelity image of the true matter distribution, allowing the dark matter halos of individual galaxies to be viewed directly, and giving a wealth of statistical and morphological information about the relative distributions of mass and light. For instrumental designs like that planned for the Square Kilometer Array (SKA), high-fidelity mass imaging may be possible near the resolution limit of the core array of the telescope.Comment: version accepted for publication in MNRAS (reduced-resolution figures

    Understanding the effect of seams on the aerodynamics of an association football

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    The aerodynamic properties of an association football were measured using a wind tunnel arrangement. A third scale model of a generic football (with seams) was used in addition to a 'mini-football'. As the wind speed was increased, the drag coefficient decreased from 0.5 to 0.2, suggesting a transition from laminar to turbulent behaviour in the boundary layer. For spinning footballs, the Magnus effect was observed and it was found that reverse Magnus effects were possible at low Reynolds numbers. Measurements on spinning smooth spheres found that laminar behaviour led to a high drag coefficient for a large range of Reynolds numbers, and Magnus effects were inconsistent, but generally showed reverse Magnus behaviour at high Reynolds number and spin parameter. Trajectory simulations of free kicks demonstrated that a football that is struck in the centre will follow a near straight trajectory, dipping slightly before reaching the goal, whereas a football that is struck off centre will bend before reaching the goal, but will have a significantly longer flight time. The curving kick simulation was repeated for a smooth ball, which resulted in a longer flight time, due to increased drag, and the ball curving in the opposite direction, due to reverse Magnus effects. The presence of seams was found to encourage turbulent behaviour, resulting in reduced drag and more predictable Magnus behaviour for a conventional football, compared with a smooth ball. © IMechE 2005

    Transnational social capital: the socio‐spatialities of civil society

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    Civil society remains a contested concept, but one that is widely embedded in global development processes. Transnationalism within civil society scholarship is often described dichotomously, either through hierarchical dependency relations or as a more amorphous networked global civil society. These two contrasting spatial imaginaries produce very particular ideas about how transnational relations contribute to civil society. Drawing on empirical material from research with civil society organizations in Barbados and Grenada, in this article I contend that civil society groups use forms of transnational social capital in their work. This does not, however, resonate with the horizontal relations associated with grassroots globalization or vertical chains of dependence. These social relations are imbued with power and agency and are entangled in situated historical, geographical and personal contexts. I conclude that the diverse transnational social relations that are part of civil society activity offer hope and possibilities for continued civil society action in these unexpected spatial arrangements

    Wolf-Rayets in IC10: Probing the Nearest Starburst

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    IC10 is the nearest starburst galaxy, as revealed both by its Halpha surface brightness and the large number of Wolf-Rayet stars (WRs) per unit area. The relative number of known WC- to WN-type WRs has been thought to be unusually high (~2), unexpected for IC10's metallicity. In this Letter we report the first results of a new and deeper survey for WRs in IC10. We sucessfully detected all of the spectroscopically known WRs, and based upon comparisons with a neighboring control field, estimate that the total number of WRs in IC10 is about 100. We present spectroscopic confirmation of two of our WR candidates, both of which are of WN type. Our photometric survey predicts that the actual WC/WN ratio is ~0.3. This makes the WC/WN ratio of IC 10 consistent with that expected for its metallicity, but greatly increases the already unusually high number of WRs, resulting in a surface density that is about 20 times higher than in the LMC. If the majority of these candidates are spectroscopically confirmed, IC10 must have an exceptional population of high mass stars.Comment: Accepted by ApJL; only minor correction in this versio

    Pipeline network features and leak detection by cross-correlation analysis of reflected waves

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    This paper describes progress on a new technique to detect pipeline features and leaks using signal processing of a pressure wave measurement. Previous work (by the present authors) has shown that the analysis of pressure wave reflections in fluid pipe networks can be used to identify specific pipeline features such as open ends, closed ends, valves, junctions, and certain types of bends. It was demonstrated that by using an extension of cross-correlation analysis, the identification of features can be achieved using fewer sensors than are traditionally employed. The key to the effectiveness of the technique lies in the artificial generation of pressure waves using a solenoid valve, rather than relying upon natural sources of fluid excitation. This paper uses an enhanced signal processing technique to improve the detection of leaks. It is shown experimentally that features and leaks can be detected around a sharp bend and up to seven reflections from features/ leaks can be detected, by which time the wave has traveled over 95 m. The testing determined the position of a leak to within an accuracy of 5%, even when the location of the reflection from a leak is itself dispersed over a certain distance and, therefore, does not cause an exact reflection of the wave

    Level density of 56^{56}Fe and low-energy enhancement of Îł\gamma-strength function

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    The 55^{55}Mn(d,n)56(d,n)^{56}Fe differential cross section is measured at Ed=7E_d=7 MeV\@. The 56^{56}Fe level density obtained from neutron evaporation spectra is compared to the level density extracted from the 57^{57}Fe(3(^3He,αγ)56\alpha\gamma)^{56}Fe reaction by the Oslo-type technique. Good agreement is found between the level densities determined by the two methods. With the level density function obtained from the neutron evaporation spectra, the 56^{56}Fe Îł\gamma-strength function is also determined from the first-generation Îł\gamma matrix of the Oslo experiment. The good agreement between the past and present results for the Îł\gamma-strength function supports the validity of both methods and is consistent with the low-energy enhancement of the Îł\gamma strength below ∌4\sim 4 MeV first discovered by the Oslo method in iron and molybdenum isotopes.Comment: 7 pages, 5 figure

    1/f Noise in Electron Glasses

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    We show that 1/f noise is produced in a 3D electron glass by charge fluctuations due to electrons hopping between isolated sites and a percolating network at low temperatures. The low frequency noise spectrum goes as \omega^{-\alpha} with \alpha slightly larger than 1. This result together with the temperature dependence of \alpha and the noise amplitude are in good agreement with the recent experiments. These results hold true both with a flat, noninteracting density of states and with a density of states that includes Coulomb interactions. In the latter case, the density of states has a Coulomb gap that fills in with increasing temperature. For a large Coulomb gap width, this density of states gives a dc conductivity with a hopping exponent of approximately 0.75 which has been observed in recent experiments. For a small Coulomb gap width, the hopping exponent approximately 0.5.Comment: 8 pages, Latex, 6 encapsulated postscript figures, to be published in Phys. Rev.

    Searching for "monogenic diabetes" in dogs using a candidate gene approach

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    BACKGROUND: Canine diabetes is a common endocrine disorder with an estimated breed-related prevalence ranging from 0.005% to 1.5% in pet dogs. Increased prevalence in some breeds suggests that diabetes in dogs is influenced by genetic factors and similarities between canine and human diabetes phenotypes suggest that the same genes might be associated with disease susceptibility in both species. Between 1-5% of human diabetes cases result from mutations in a single gene, including maturity onset diabetes of the adult (MODY) and neonatal diabetes mellitus (NDM). It is not clear whether monogenic forms of diabetes exist within some dog breeds. Identification of forms of canine monogenic diabetes could help to resolve the heterogeneity of the condition and lead to development of breed-specific genetic tests for diabetes susceptibility. RESULTS: Seventeen dog breeds were screened for single nucleotide polymorphisms (SNPs) in eighteen genes that have been associated with human MODY/NDM. Six SNP associations were found from five genes, with one gene (ZFP57) being associated in two different breeds. CONCLUSIONS: Some of the genes that have been associated with susceptibility to MODY and NDM in humans appear to also be associated with canine diabetes, although the limited number of associations identified in this study indicates canine diabetes is a heterogeneous condition and is most likely to be a polygenic trait in most dog breeds. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2052-6687-1-8) contains supplementary material, which is available to authorized users

    Density Functional Theory for the Photoionization Dynamics of Uracil

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    Photoionization dynamics of the RNA base Uracil is studied in the framework of Density Functional Theory (DFT). The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results providing a guide for future experimental work on similar biosystems
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