2,161 research outputs found

    Development of explosive forming techniques for Saturn V components Final report, 24 Jun. 1964 - 28 Jan. 1966

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    Explosive forming techniques development for aluminum alloy, carbon steel, and titanium components for Saturn V launch vehicl

    Popular music, psychogeography, place identity and tourism: The case of Sheffield

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    Tourism and cultural agencies in some English provincial cities are promoting their popular music ‘heritage’ and, in some cases, contemporary musicians through the packaging of trails, sites, ‘iconic’ venues and festivals. This article focuses on Sheffield, a ‘post-industrial’ northern English city which is drawing on its associations with musicians past and present in seeking to attract tourists. This article is based on interviews with, among others, recording artists, promoters, producers and venue managers, along with reflective observational and documentary data. Theoretical remarks are made on the representations of popular musicians through cultural tourism strategies, programmes and products and also on the ways in which musicians convey a ‘psychogeographical’ sense of place in the ‘soundscape’ of the city

    Statistical Mechanics of Logarithmic REM: Duality, Freezing and Extreme Value Statistics of 1/f1/f Noises generated by Gaussian Free Fields

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    We compute the distribution of the partition functions for a class of one-dimensional Random Energy Models (REM) with logarithmically correlated random potential, above and at the glass transition temperature. The random potential sequences represent various versions of the 1/f noise generated by sampling the two-dimensional Gaussian Free Field (2dGFF) along various planar curves. Our method extends the recent analysis of Fyodorov Bouchaud from the circular case to an interval and is based on an analytical continuation of the Selberg integral. In particular, we unveil a {\it duality relation} satisfied by the suitable generating function of free energy cumulants in the high-temperature phase. It reinforces the freezing scenario hypothesis for that generating function, from which we derive the distribution of extrema for the 2dGFF on the [0,1][0,1] interval. We provide numerical checks of the circular and the interval case and discuss universality and various extensions. Relevance to the distribution of length of a segment in Liouville quantum gravity is noted.Comment: 25 pages, 12 figures Published version. Misprint corrected, references and note adde

    Wasted Words?: Current Trends in Collection Development Policies

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    The transition to electronic resources and the changing role of the collection development librarian are having a tremendous impact on the manner by which libraries select and acquire new materials. The goal of this research project was to further elucidate the current trends of collection development policies in members of the Association of Research Libraries (ARL) as well as gauge current use and future efficacy. The survey was designed and sent to librarians responsible for collection development at university-affiliated ARL libraries in order to obtain a current picture of academic collection development policies, and how they are changing due to the abundance of electronic resources and new methods of data-driven acquisitions. The goals of the survey are to Measure the continued use of CD policies as major collection-building tools; Assess the frequency of updates to collection development policies; Determine the availability of collection development policies; Measure and compare the amount of time available to librarians to review and select new materials; Determine if print materials are being reviewed in new and innovative ways or if they receive the same assessment as electronically formatted materials; Measure the employment of data or patron-driven acquisition methods. The findings will require additional assessment, but the data does seem to indicate a time of change in the way academic libraries complete and assess their primary collection development activities. This survey was created, at least in part, with the hope of setting a starting point for continued evaluation and longitudinal measurement. If our survey participants are as actively helpful in future years, these dreams of cyclical assessment may well come to fruition

    A Holder Continuous Nowhere Improvable Function with Derivative Singular Distribution

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    We present a class of functions K\mathcal{K} in C0(R)C^0(\R) which is variant of the Knopp class of nowhere differentiable functions. We derive estimates which establish \mathcal{K} \sub C^{0,\al}(\R) for 0<\al<1 but no KKK \in \mathcal{K} is pointwise anywhere improvable to C^{0,\be} for any \be>\al. In particular, all KK's are nowhere differentiable with derivatives singular distributions. K\mathcal{K} furnishes explicit realizations of the functional analytic result of Berezhnoi. Recently, the author and simulteously others laid the foundations of Vector-Valued Calculus of Variations in LL^\infty (Katzourakis), of LL^\infty-Extremal Quasiconformal maps (Capogna and Raich, Katzourakis) and of Optimal Lipschitz Extensions of maps (Sheffield and Smart). The "Euler-Lagrange PDE" of Calculus of Variations in LL^\infty is the nonlinear nondivergence form Aronsson PDE with as special case the \infty-Laplacian. Using K\mathcal{K}, we construct singular solutions for these PDEs. In the scalar case, we partially answered the open C1C^1 regularity problem of Viscosity Solutions to Aronsson's PDE (Katzourakis). In the vector case, the solutions can not be rigorously interpreted by existing PDE theories and justify our new theory of Contact solutions for fully nonlinear systems (Katzourakis). Validity of arguments of our new theory and failure of classical approaches both rely on the properties of K\mathcal{K}.Comment: 5 figures, accepted to SeMA Journal (2012), to appea

    Pulsed rotating supersonic source used with merged molecular beams

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    We describe a pulsed rotating supersonic beam source, evolved from an ancestral device [M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001)]. The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, cryocooling, and a shutter gate eliminated the main handicap of the original device, in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1-0.6 ms (depending on rotor speed) and containing ~10^12 molecules at lab speeds as low as 35 m/s and ~ 10^15 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, Cl2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when using two merged beams. By closely matching the beam speeds, very low relative collision energies can be attained without making either beam very slow.Comment: 26 pages, 10 figure

    Laminate polyethylene window development for large aperture millimeter receivers

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    New experiments that target the B-mode polarization signals in the Cosmic Microwave Background require more sensitivity, more detectors, and thus larger-aperture millimeter-wavelength telescopes, than previous experiments. These larger apertures require ever larger vacuum windows to house cryogenic optics. Scaling up conventional vacuum windows, such as those made of High Density Polyethylene (HDPE), require a corresponding increase in the thickness of the window material to handle the extra force from the atmospheric pressure. Thicker windows cause more transmission loss at ambient temperatures, increasing optical loading and decreasing sensitivity. We have developed the use of woven High Modulus Polyethylene (HMPE), a material 100 times stronger than HDPE, to manufacture stronger, thinner windows using a pressurized hot lamination process. We discuss the development of a specialty autoclave for generating thin laminate vacuum windows and the optical and mechanical characterization of full scale science grade windows, with the goal of developing a new window suitable for BICEP Array cryostats and for future CMB applications

    Wolbachia and DNA barcoding insects: patterns, potential and problems

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    Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region

    Utilization of health services in relation to mental health problems in adolescents: A population based survey

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    BACKGROUND: Only a minority of adolescents reporting symptoms above case-levels on screenings for mental health seeks and receives help from specialist health services. The objective of this study was to a) examine help-seeking for symptoms of anxiety and depression in relation to symptom load dimensionally, b) identify the level of specialization in mental health among service-providers, and c) identify associations between mental health problems and contact with different types of health services. METHODS: This cross-sectional school-based study (response-rate 88%, n = 11154) is based on Norwegian health surveys among 15 and 16 year olds. RESULTS: We found a dose-response association between symptom-load and help seeking. Only 34% of individuals with mental symptom-load above 99(th )percentile reported help-seeking in the last 12 months. Forty percent of help seekers were in contact with specialists (psychiatrists or psychologists), the remaining were mainly in contact with GPs. Mental health problems increased help seeking to all twelve service providers examined. CONCLUSION: It might not be reasonable to argue that all adolescents with case-level mental health problems are in need of treatment. However, concerning the 99(th )percentile, claiming treatment need is less controversial. Even in the Norwegian context where mental health services are relatively available and free of charge, help-seeking in individuals with the highest symptom-loads is still low. Most help seekers achieved contact with health care providers, half of them at a non specialized level. Our results suggest that adolescents' recognition of mental health problems or intention to seek help for these are the major "filters" restricting treatment

    A genome-wide scan for common alleles affecting risk for autism

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    Although autism spectrum disorders (ASDs) have a substantial genetic basis, most of the known genetic risk has been traced to rare variants, principally copy number variants (CNVs). To identify common risk variation, the Autism Genome Project (AGP) Consortium genotyped 1558 rigorously defined ASD families for 1 million single-nucleotide polymorphisms (SNPs) and analyzed these SNP genotypes for association with ASD. In one of four primary association analyses, the association signal for marker rs4141463, located within MACROD2, crossed the genome-wide association significance threshold of P < 5 × 10−8. When a smaller replication sample was analyzed, the risk allele at rs4141463 was again over-transmitted; yet, consistent with the winner's curse, its effect size in the replication sample was much smaller; and, for the combined samples, the association signal barely fell below the P < 5 × 10−8 threshold. Exploratory analyses of phenotypic subtypes yielded no significant associations after correction for multiple testing. They did, however, yield strong signals within several genes, KIAA0564, PLD5, POU6F2, ST8SIA2 and TAF1C
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