4,083 research outputs found

    Exploiting multimedia in creating and analysing multimedia Web archives

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    The data contained on the web and the social web are inherently multimedia and consist of a mixture of textual, visual and audio modalities. Community memories embodied on the web and social web contain a rich mixture of data from these modalities. In many ways, the web is the greatest resource ever created by human-kind. However, due to the dynamic and distributed nature of the web, its content changes, appears and disappears on a daily basis. Web archiving provides a way of capturing snapshots of (parts of) the web for preservation and future analysis. This paper provides an overview of techniques we have developed within the context of the EU funded ARCOMEM (ARchiving COmmunity MEMories) project to allow multimedia web content to be leveraged during the archival process and for post-archival analysis. Through a set of use cases, we explore several practical applications of multimedia analytics within the realm of web archiving, web archive analysis and multimedia data on the web in general

    Adoption policy in Great Britain and North America

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    Journal ArticleThis paper has two purposes. First, to explore what existing adoption legislation may indicate about the meaning and function of adoption practices in North America and Great Britain. Second, to consider some possible policy implications revealed by clearer understanding of the social meaning of existing adoption laws. The first part of the paper summarizes briefly the history of legal adoption. The second examines what is explicitly and implicitly revealed by adoption law and policies about the social purposes of adoption and about prevailing social values concerning the family. The third part examines possible avenues of policy change in North America

    Survey of lift-fan aerodynamic technology

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    Representatives of NASA Ames Research Center asked that a summary of technology appropriate for lift-fan powered short takeoff/vertical landing (STOVL) aircraft be prepared so that new programs could more easily benefit from past research efforts. This paper represents one of six prepared for that purpose. The authors have conducted or supervised the conduct of research on lift-fan powered STOVL designs and some of their important components for decades. This paper will first address aerodynamic modeling requirements for experimental programs to assure realistic, trustworthy results. It will next summarize the results or efforts to develop satisfactory specialized STOVL components such as inlets and flow deflectors. It will also discuss problems with operation near the ground, aerodynamics while under lift-fan power, and aerodynamic prediction techniques. Finally, results of studies to reduce lift-fan noise will be presented. The paper will emphasize results from large scale experiments, where available, for reasons that will be brought out in the discussion. Some work with lift-engine powered STOVL aircraft is also applicable to lift-fan technology and will be presented herein. Small-scale data will be used where necessary to fill gaps

    Astrophysical Supercomputing with GPUs: Critical Decisions for Early Adopters

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    General purpose computing on graphics processing units (GPGPU) is dramatically changing the landscape of high performance computing in astronomy. In this paper, we identify and investigate several key decision areas, with a goal of simplyfing the early adoption of GPGPU in astronomy. We consider the merits of OpenCL as an open standard in order to reduce risks associated with coding in a native, vendor-specific programming environment, and present a GPU programming philosophy based on using brute force solutions. We assert that effective use of new GPU-based supercomputing facilities will require a change in approach from astronomers. This will likely include improved programming training, an increased need for software development best-practice through the use of profiling and related optimisation tools, and a greater reliance on third-party code libraries. As with any new technology, those willing to take the risks, and make the investment of time and effort to become early adopters of GPGPU in astronomy, stand to reap great benefits.Comment: 13 pages, 5 figures, accepted for publication in PAS

    The experience of accommodating privacy restrictions during implementation of a large-scale surveillance study of an osteoporosis medication.

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    PurposeTo explore whether privacy restrictions developed to protect patients have complicated research within a 15-year surveillance study conducted with US cancer registries.MethodsData from enrolling 27 cancer registries over a 10-year period were examined to describe the amount of time needed to obtain study approval. We also analyzed the proportion of patients that completed a research interview out of the total reported by the registries and examined factors thought to influence this measure.ResultsThe average length of the research review process from submission to approval of the research was 7 months (range, <1 to 24 months), and it took 6 months or more to obtain approval of the research at 41% of the cancer registries. Most registries (78%) required additional permission steps to gain access to patients for research. After adjustment for covariates, the interview response proportion was 110% greater (ratio of response proportion = 2.1; 95% confidence interval: 1.3, 3.3) when the least restrictive versus the most restrictive permission steps were required. An interview was more often completed for patients (or proxies) if patients were alive, within a year of being diagnosed, or identified earlier in the study.ConclusionsLengthy research review processes increased the time between diagnosis and provision of patient information to the researcher. Requiring physician permission for access to patients was associated with lower subject participation. A single national point of entry for use of cancer registry data in health research is worthy of consideration to make the research approval process efficient. © 2016 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd

    Photothermal Fluctuations as a Fundamental Limit to Low-Frequency Squeezing in a Degenerate Optical Parametric Amplifier

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    We study the effect of photothermal fluctuations on squeezed states of light through the photo-refractive effect and thermal expansion in a degenerate optical parametric amplifier (OPA). We also discuss the effect of the photothermal noise in various cases and how to minimize its undesirable consequences. We find that the photothermal noise in the OPA introduces a significant amount of noise on phase squeezed beams, making them less than ideal for low frequency applications such as gravitational wave (GW) interferometers, whereas amplitude squeezed beams are relatively immune to the photothermal noise and may represent the best choice for application in GW interferometers

    The longitudinal association between homelessness, injection drug use, and injection-related risk behavior among persons with a history of injection drug use in Baltimore, MD

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    AbstractBackgroundFew studies have assessed the temporal association between homelessness and injection drug use, and injection-related risk behavior.MethodsAmong a cohort of 1405 current and former injection drug users in follow-up from 2005 to 2009, we used random intercept models to assess the temporal association between homelessness and subsequent injection drug use, and to determine whether the association between homelessness and sustained injection drug use among active injectors differed from the association between homelessness and relapse among those who stopped injecting. We also assessed the association between homelessness and subsequent injection-related risk behavior among participants who injected drugs consecutively across two visits. Homelessness was categorized by duration: none, <1 month, and ≄1 month.ResultsHomelessness was reported on at least one occasion by 532 (38%) participants. The relationship between homelessness and subsequent injection drug use was different for active injectors and those who stopped injecting. Among those who stopped injecting, homelessness was associated with relapse [<1 month: AOR=1.67, 95% CI (1.01, 2.74); ≄1 month: AOR=1.34 95% CI (0.77, 2.33)]. Among active injectors, homelessness was not associated with sustained injection drug use [<1 month: AOR=1.03, 95% CI (0.71, 1.49); ≄1 month: AOR=0.81 95% CI (0.56, 1.17)]. Among those injecting drugs across two consecutive visits, homelessness ≄1 month was associated with subsequent injection-related risk behavior [AOR=1.61, 95% CI (1.06, 2.45)].ConclusionHomelessness appears to be associated with relapse and injection-related risk behavior. Strengthening policies and interventions that prevent homelessness may reduce injection drug use and injection-related risk behaviors

    Solute Concentrations Influence Microbial Methanogenesis in Coal-bearing Strata of the Cherokee Basin, USA

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    Microorganisms have contributed significantly to subsurface energy resources by converting organic matter in hydrocarbon reservoirs into methane, the main component of natural gas. In this study, we consider environmental controls on microbial populations in coal-bearing strata of the Cherokee basin, an unconventional natural gas resource in southeast Kansas, USA. Pennsylvanian-age strata in the basin contain numerous thin (0.4-1.1 m) coalbeds with marginal thermal maturities (0.5-0.7% Ro) that are interbedded with shale and sandstone. We collected gas, water, and microbe samples from 16 commercial coalbed methane wells for geochemical and microbiological analysis. The water samples were Na-Cl type with total dissolved solids (TDS) content ranging from 34.9 to 91.3 g L?1. Gas dryness values [C1/(C2 + C3)] averaged 2640 and carbon and hydrogen isotope ratios of methane differed from those of carbon dioxide and water, respectively, by an average of 65 and 183%. These values are thought to be consistent with gas that formed primarily by hydrogenotrophic methanogenesis. Results from cultivation assays and taxonomic analysis of 16S rRNA genes agree with the geochemical results. Cultivable methanogens were present in every sample tested, methanogen sequences dominate the archaeal community in each sample (avg 91%), and few archaeal sequences (avg 4.2%) were classified within Methanosarcinales, an order of methanogens known to contain methylotrophic methanogens. Although hydrogenotrophs appear dominant, geochemical and microbial analyses both indicate that the proportion of methane generated by acetoclastic methanogens increases with the solute content of formation water, a trend that is contrary to existing conceptual models. Consistent with this trend, beta diversity analyses show that archaeal diversity significantly correlates with formation water solute content. In contrast, bacterial diversity more strongly correlates with location than solute content, possibly as a result of spatial variation in the thermal maturity of the coalbeds.Citation: Kirk MF, Wilson BH, Marquart KA, Zeglin LH, Vinson DS and Flynn TM (2015) Solute Concentrations Influence Microbial Methanogenesis in Coal-bearing Strata of the Cherokee Basin, USA. Front. Microbiol. 6:1287. doi: 10.3389/fmicb.2015.0128

    Polarization speed meter for gravitational-wave detection

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    We propose a modified configuration of an advanced gravitational-wave detector that is a speed-meter-type interferometer with improved sensitivity with respect to quantum noise. With the addition of polarization-controlling components to the output of an arm cavity Michelson interferometer, an orthogonal polarization state of the interferometer can be used to store signal, returning it later with opposite phase to cancel position information below the storage bandwidth of the opposite mode. This modification provides an alternative to an external kilometer-scale Fabry-PĂ©rot cavity, as presented in earlier work of Purdue and Chen [Phys. Rev. D 66, 122004 (2002)]. The new configuration requires significantly less physical infrastructure to achieve speed meter operation. The quantity of length and alignment degrees of freedom is also reduced. We present theoretical calculations to show that such a speed meter detector is capable of beating the strain sensitivity imposed by the standard quantum limit over a broad range of frequencies for Advanced Laser Interferometer Gravitational-wave Observatory-like parameters. The benefits and possible difficulties of implementing such a scheme are outlined. We also present results for tuning of the speed meter by adjusting the degree of polarization coupling, a novel possibility that does not exist in previously proposed designs, showing that there is a smooth transition from speed meter operation to that of a signal-recycling Michelson behavior
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