A coded-aperture technique allowing x-ray phase contrast imaging with conventional sources

Phase contrast imaging (PCI) solves the basic limitation of x-ray imaging, i.e., poor image contrast resulting from small absorption differences. Up to now, it has been mostly limited to synchrotron radiation facilities, due to the stringent requirements on the x-ray source and detectors, and only one technique was shown to provide PCI images with conventional sources but with limits in practical implementation. The authors propose a different approach, based on coded apertures, which provides high PCI signals with conventional sources and detectors and imposes practically no applicability limits. They expect this method to cast the basis of a widespread diffusion of PCI. (C) 2007 American Institute of Physics

Food-Security Status and Food-Purchase Decisions of Low-Income Households in Tennessee

Consumer/Household Economics, Food Security and Poverty,

Aluminium Nanowires: Influence of Work Hardening on Conductance Histograms

Conductance histograms of work-hardened Al show a series up to 11 equidistant peaks with a period of 1.15 +/- 0.02 of the quantum conductance unit G_0 = 2e^2/h. Assuming the peaks originate from atomic discreteness, this agrees with the value of 1.16 G_0 per atom obtained in numerical calculations by Hasmy et al.Comment: 4 pages, 4 figure

Introduction : Bourdieu and the literary field

Pierre Bourdieu’s range as a thinker was extremely wide, and it would be misleading to present him primarily as a literary theorist. Trained as a philosopher, he became the leading French sociologist of his generation, and brought under the spotlight of his ‘critical sociology’ a whole series of institutional and discursive universes (education, art, linguistics, public administration, politics, philosophy, journalism, economics and others). Far from representing an intellectual dispersal, these manifold objects of enquiry allowed him to develop and refine a comprehensive theory of social process and power-relations based on distinctive concepts such as ‘field’, ‘habitus’, variously conceived notions of ‘capital’, and ‘illusio’ (all these concepts and others will be explicated and assessed in this issue). Yet Bourdieu’s analyses were scarcely ever received as neutral descriptions within the fields which he analysed. Bourdieu’s abiding agenda was to show how the discursive presuppositions and institutional logics at work in such fields carried but also masked certain social logics that a ‘critical sociology’ could disclose. Coupled with the inveterately combative drive seldom absent from Bourdieu’s objectifying analyses—and even setting aside the misprisions to which an external analyst is inevitably subject—this helps explain the resistance which his work recurrently provoked. In this respect, Bourdieu’s forays into the world of literary studies and his reception therein can be seen as part of a wider pattern

Conductance of Pd-H nanojunctions

Results of an experimental study of palladium nanojunctions in hydrogen environment are presented. Two new hydrogen-related atomic configurations are found, which have a conductances of ~0.5 and ~1 quantum unit (2e^2/h). Phonon spectrum measurements demonstrate that these configurations are situated between electrodes containing dissolved hydrogen. The crucial differences compared to the previously studied Pt-H_2 junctions, and the possible microscopic realizations of the new configurations in palladium-hydrogen atomic-sized contacts are discussed.Comment: 4 pages, 4 figure

Network theory approach for data evaluation in the dynamic force spectroscopy of biomolecular interactions

Investigations of molecular bonds between single molecules and molecular complexes by the dynamic force spectroscopy are subject to large fluctuations at nanoscale and possible other aspecific binding, which mask the experimental output. Big efforts are devoted to develop methods for effective selection of the relevant experimental data, before taking the quantitative analysis of bond parameters. Here we present a methodology which is based on the application of graph theory. The force-distance curves corresponding to repeated pulling events are mapped onto their correlation network (mathematical graph). On these graphs the groups of similar curves appear as topological modules, which are identified using the spectral analysis of graphs. We demonstrate the approach by analyzing a large ensemble of the force-distance curves measured on: ssDNA-ssDNA, peptide-RNA (system from HIV1), and peptide-Au surface. Within our data sets the methodology systematically separates subgroups of curves which are related to different intermolecular interactions and to spatial arrangements in which the molecules are brought together and/or pulling speeds. This demonstrates the sensitivity of the method to the spatial degrees of freedom, suggesting potential applications in the case of large molecular complexes and situations with multiple binding sites

NON-PROFIT FOOD CENTERS IN TENNESSEE: SURVEY FINDINGS

Agribusiness,

Reporting suicide: what lessons has the media learnt?

Last December, the Press Complaints Commission teamed up with Polis to organise a seminar about how suicide is reported by the media. The idea of holding a discussion to bring together journalists, academics, regulatory bodies and those with specialist knowledge of mental health issues stemmed from the spate of suicides in and around Bridgend earlier that year, and the widespread public debate the media coverage of those deaths generated

Progress, pressures and politics: challenges at self-regulatory media councils in South East Europe

Catherine Speller is a consultant working on communications, media and policy matters who recently completed a report for UNESCO on the needs of media councils in South East Europe. She previously spent seven years at the UK Press Complaints Commission. Here, she highlights the main challenges faced by the self-regulatory media councils in this region

The business and dynamics of free-to-play social-casual game apps

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 95-100).The rapid growth of social media platforms, specifically Facebook, has caused startup firms to develop new business models based on social technologies. By leveraging the Facebook platform, new entertainment companies making free-to-play social-casual games have created a multi-billion dollar market for virtual goods, a revenue model in which the core product is given away for free and ancillary goods are sold on top of it. Zynga, the most successful firm in this space, held the largest initial public offering for an Internet-based company since Google in 2004. However, concerns about Zynga's longevity (as well as the longevity of other social-oriented firms, including Groupon) persist for a variety of reasons, including the novelty of its business model, the dependence on hit products with short lifecycles, and the stress placed on internal development teams. This thesis analyzes some of the key problems faced by Zynga and its competitors, including how to monetize free products, how to maintain a user base over time (using platform strategy concepts), and how to develop short and long-term product management and new product development policies (using System Dynamics). An additional chapter develops principles for launching social platforms and products by comparing and contrasting key factors that influenced the growth of five major social media websites. The principles are then discussed as they pertain to Zynga and social-casual gaming, in which case there are notable applications and key exceptions based on Zynga's circumstances. The thesis concludes by discussing several future areas of research that pertain to the socialization of products and technology.by Thomas Hughes Speller, III.S.M.in Engineering and Managemen