1,095 research outputs found

    Correlation inequalities for the quantum XY model

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    We show the positivity or negativity of truncated correlation functions in the quantum XY model with spin 1/2 (at any temperature) and spin 1 (in the ground state). These Griffiths-Ginibre inequalities of the second kind generalise an earlier result of Gallavotti.Comment: 9 page

    State Power Plant Siting: a Sketch of the Main Features of a Possible Approach

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    Work on various phases of power plant technology and siting has been underway within the Environmental Quality Laboratory (EQL) at the California Institute of Technology for some time. Of particular relevance to this memorandum, a good deal of effort has been devoted to institutional aspects of the siting process. Our purpose in what follows is to draw from our past work -- and from the discussions and work of others -- a sketch of the major outlines of one possible approach to power plant siting for the state. We hope in doing so to give our present views about the issues and how they might rationally be resolved, not so much to convince as to inform, stimulate fruitful ideas, and help provide the basis for constructive debate. We ourselves are not necessarily wedded to any of the discussion that follows; we find our own minds changing from time to time as we study the problem further or confront sound suggestions from others. Part I of this memorandum briefly outlines the major features of what we see as a fruitful approach to the siting problem. Sections A through E of Part I describe some elements of the approach; Section F sketches the actual siting decision process we suggest, and in doing so shows how the elements play into the process. Section G comments briefly on a suggested role for judicial review. In Part II we attempt to reduce our ideas to a fairly precise outline for a state siting statute, and to deal with certain matters of detail not covered in Part I. Section A of Part II introduces the statutory outline by summarizing each of its provisions; Section B sets forth the outline itself. The Appendix to this memorandum depicts our suggested approach in time-line fashion; it should be helpful in reading and understanding the proposal

    #AllCatsAreBeautiful: Ambient affiliation and the visual-verbal representation and appreciation of cats in online subversive discourses

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    This paper investigates the topics and affiliations associated with the hashtag #AllCatsAreBeautiful on the social media platform Twitter. Drawing on concepts from social semiotics (systemic functional theory) and critical animal studies, the paper identifies a number of potentially overlapping topics or fields, including anti-policing, the commodification of nonhuman animals, gender and sexism, and body image or body-shaming, as well as a more general positive appreciation or admiration of cats. The paper discusses how people position themselves in relation to those topics, through patterns of ideational and attitudinal meanings, and how cats are represented and appreciated visually, verbally and intersemiotically. Cats, in this context, play an important role in struggles for social justice, symbolizing freedom and resistance as well as love and solidarity. #AllCatsAreBeautiful highlights topics or spaces around which bonds can be made and communities of shared values or interests can be co-constructed.publishedVersio

    A GATHERING OF FLOWERS : ON DESIGN ANTHOLOGIES

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    This is an Accepted Manuscript of an article published by Taylor & Francis in The Design History on 12 May 2017, available online at: http://www.tandfonline.com/doi/abs/10.1080/14606925.2017.1323426 Under embargo. Embargo end date: 12 November 2018.Over the past decade, anthologies ā€“ also called ā€˜readersā€™ ā€“ of design history and theory have proliferated across publishersā€™ catalogues. These books perform important pedagogical functions: they define fields and establish canons of authoritative texts, authors and concepts. While detractors argue that the easy availability of textual sources online means that we no longer need anthologies, the opposite argument can be made: the overwhelming volume of electronic information sharpens the need for concise, edited selections. This article examines the practices of selecting, editing and publishing anthologies and reasons for their increasing popularity, particularly in design education, at the present time.Peer reviewe

    Truss structure design

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    An integrally formed three-dimensional truss structure, including molds and methods for production of same, containing outer top and bottom plane surfaces thereof comprising interconnected rod segments integrally formed at their points of intersection on the outer top and bottom surfaces, the top and bottom surfaces also integrally joined together through additional interconnected rod segments passing through an integrally formed intersection, wherein the additional interconnected rod segments passing through the integrally formed intersection form a three-dimensional continuous array of triangles

    Heparin-stabilised iron oxide for MR applications : a relaxometric study

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    Superparamagnetic nanoparticles have strong potential in biomedicine and have seen application as clinical magnetic resonance imaging (MRI) contrast agents, though their popularity has plummeted in recent years, due to low efficacy and safety concerns, including haemagglutination. Using an in situ procedure, we have prepared colloids of magnetite nanoparticles, exploiting the clinically approved anti-coagulant, heparin, as a templating stabiliser. These colloids, stable over several days, produce exceptionally strong MRI contrast capabilities particularly at low fields, as demonstrated by relaxometric investigations using nuclear magnetic resonance dispersion (NMRD) techniques and single field r1 and r2 relaxation measurements. This behaviour is due to interparticle interactions, enhanced by the templating effect of heparin, resulting in strong magnetic anisotropic behaviour which closely maps particle size. The nanocomposites have also reliably prevented protein-adsorption triggered thrombosis typical of non-stabilised nanoparticles, showing great potential for in vivo MRI diagnostics

    Neonatal tolerance to Mls-1a determinants: deletion or anergy of VĪ²6 + T lymphocytes depending upon MHC compatibility of neonatally injected cells

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    Recent investigations in mice revealed that natural immunologlcal tolerance to endogenous minor lymphocyte-stimulating locus 1a (MIs-1a antigen correlates primarily with deletion of Mls-1aspeciflc VĪ²6+ T lymphocytes In the thymus. Similar mechanisms account for acquired tolerance in some Instancessince the neonatal injection of Mls-1 a-expressing MHC compatible cells in neonatal mice within the first 24 hof life causes clonal deletion of VĪ²6+ T cells. Here we demonstrate that VĪ²6+ T cells are not deleted In mice neonatally treated with Mls-1a spleen cells expressing allogenelc H-2 molecules. However, when such non-deleted VĪ²6+ T cells were tested In vitro, no interleukin 2 (IL-2) secretion or proliferation was observed after Mls-1a stimulation. This non-responsive state could be overcome by addition of exogenous IL-2, consistent with the fact that VĪ²6+ cells enlarged and expressed IL-2 receptors upon Mls-1a stimulation. Furthermore, the same neonatally treated mice showed In vitro functional unresponsiveness of cytotoxic T cells but not of IL-2-secreting cells specific for the tolerated allogeneic MHC antigens. Taken together, our data Indicate that neonatal tolerance to Mls-1a can be accomplished by either clonal deletion or clonal anergy, and that it does not necessarily correlate with tolerance to MHC determinant

    Origins and population genetics of sambar deer (Cervus unicolor) introduced to Australia and New Zealand

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    Context. Some populations of introduced species cause significant undesirable impacts but can also act as reservoirs for genetic diversity. Sambar deer (Cervus unicolor) are ā€˜Vulnerableā€™ in their native range and invasive in Australia and New Zealand. Genetic data can be used to determine whether these introduced populations might serve as genetic reservoirs for declining native populations and to identify spatial units for management. Aims. We aimed to identify the provenance of sambar deer in Australia and New Zealand, and to characterise their genetic diversity and population structure. Methods. We used mitochondrial control region sequences and 18 nuclear microsatellite loci of 24 New Zealand and 63 Australian sambar deer collected across continuous habitat in each location. We estimated genetic diversity and population differentiation by using pairwise FST, AMOVA, and STRUCTURE analyses. We compared our data with 27 previously published native and invasive range sequences to identify phylogenetic relationships. Key results. Sambar deer in Australia and New Zealand are genetically more similar to those in the west of the native range (South and Central Highlands of India, and Sri Lanka), than to those in the east (eastern India, and throughout Southeast Asia). Nuclear genetic diversity was lower than in the native range; only one mitochondrial haplotype was found in each introduced population. Australian and New Zealand sambar deer were genetically distinct but there was no population structure within either population. Conclusions. The genetic differences we identified between these two introduced populations at putatively neutral loci indicate that there also may be underlying diversity at functional loci. The lack of population genetic structure that we found within introduced populations suggests that individuals within these popula- tions do not experience barriers to dispersal across the areas sampled. Implications. Although genetic diversity is reduced in the introduced range compared with the native range, sambar deer in Australia and New Zealand harbour unique genetic variants that could be used to strengthen genetic diversity in populations under threat in the native range. The apparent high levels of gene flow across the areas we sampled suggest that localised control is unlikely to be effective in Australia and New Zealand

    Superconductivity and the upper critical field in the chiral noncentrosymmetric superconductor NbRh2B2

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    NbRh2B2 crystallises in a chiral noncentrosymmetric structure and exhibits bulk type-II superconductivity below 7.46(5) K. Here we show that the temperature dependence of the upper critical field deviates from the behaviour expected for both Werthamer-Helfand-Hohenberg and the Ginzburg-Landau models and that Ī¼0Hc2 (0) ~ 18 T exceeds the Pauli paramagnetic limit, Ī¼0HP = 13.9 T. We explore the reasons for this enhancement. Transverse-field muon spectroscopy measurements suggest that the superconducting gap is either s-wave or (s + s)-wave, a the pressure dependence of Tc reveals the superconducting gap is primarily s- wave in character. The magnetic penetration depth lambda(0) = 595(5) nm. Heat capacity measurements reveal the presence of a multigap (s + s)-wave superconducting order parameter and moderate electron-phonon coupling

    Design for On-Site Hydrogen Production for Hydrogen Fuel Cell Vehicle Refueling Station at University of Birmingham, U.K.

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    In April 2008, the University of Birmingham launched the first permanent Hydrogen Refuelling Station in the UK. This enabled the refuelling of the only at the time fleet of Hydrogen Hybrid Fuel Cell Vehicles (HHFCV) in the UK. To maintain the low emissions ethos, the ultra-high purity ā€œGreenā€ hydrogen for the refuelling station was supplied off site, from a third party contractor. The University aims to be the first campus in the UK that is carbon neutral and this project scopes to produce ā€œGreenā€ hydrogen on-site to power the fleet of HHFCVs. Electrolysis is currently the only commercial method for producing ultra-high purity hydrogen without the need for, what could prove to be very costly, additional purification steps. Working in collaboration with ITM Power, a HPac Model electrolyser has been installed to produce electrolytic hydrogen on-site (up to 1.25 kgH2/day). The HPac uses PEM technology, which eliminates the need for hazardous alkaline substances, to produce hydrogen. The input requirements are ASTM Type 2 de-ionised (DI), water and 240 V power supply. Hydrogen is produced at pressures up to 15 bar [1]. However, there is a need to incorporate this unit within the existing hydrogen infrastructure incorporating 350 bar Air Product refuelling station. An integrated delivery system has been designed and initial results are presented herein
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