207 research outputs found

    An Extended UTAUT Model for the Study of Negative User Adoption Behaviours of Mobile Commerce

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    An extended Unified Theory of Acceptance and Use of Technology (UTAUT) for mobile commerce (m-commerce) was empirically tested using data collected from a web survey distributed to and through the Hong Kong undergraduates and postgraduates. The partial least squares (PLS) technique of the structural equation modeling (SEM) was used to evaluate the causal model and the confirmatory factor analysis (CFA) was performed to examine the reliability and validity of the measurement model. Findings indicated that the new construct of Disturbance Concerns (DC) is a significant factor affecting users’ behavioural intention. This study aims to understand both the positive and negative factors that can significantly explain user acceptance intention and use behaviour so that service providers can adjust their strategies for providing successful m-commerce services. It also provides a base for further research on the user acceptance models of new information systems

    Exploratory fMRI analysis without spatial normalization

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    Author Manuscript received 2010 March 11. 21st International Conference, IPMI 2009, Williamsburg, VA, USA, July 5-10, 2009. ProceedingsWe present an exploratory method for simultaneous parcellation of multisubject fMRI data into functionally coherent areas. The method is based on a solely functional representation of the fMRI data and a hierarchical probabilistic model that accounts for both inter-subject and intra-subject forms of variability in fMRI response. We employ a Variational Bayes approximation to fit the model to the data. The resulting algorithm finds a functional parcellation of the individual brains along with a set of population-level clusters, establishing correspondence between these two levels. The model eliminates the need for spatial normalization while still enabling us to fuse data from several subjects. We demonstrate the application of our method on a visual fMRI study.McGovern Institute for Brain Research at MIT. Neurotechnology ProgramNational Science Foundation (U.S.) (CAREER Grant 0642971)National Institutes of Health (U.S.) (NIBIB NAMIC U54-EB005149)National Institutes of Health (U.S.) (NCRR NAC P41-RR13218

    The Prevalence of Sex Trafficking of Children and Adolescents in the United States: A Scoping Review

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    Topic: This scoping review investigated research regarding the magnitude of minor sex trafficking (domestic minor sex trafficking and/or commercial sexual exploitation of children) in the United States, summarizing estimates, methodologies, and strengths and weaknesses of the studies. Method: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, peer-reviewed articles and the gray literature were accessed via databases searches, reference harvesting, and expert advice. Articles were included if they provided a count or prevalence proportion estimate of trafficked or at-risk minors across or within a region of the United States. Six empirical studies, published from 1999 to 2017, were included in the review. Results: Included studies produced count estimates (n = 3) or prevalence proportion estimates (n = 3) for youth at risk of minor sex trafficking (n = 2) or reporting victimization (n = 5). Studies examined sex trafficking risk and victimization in different geographical areas, including across the United States (n = 2), in New York City (n = 1), and in Ohio (n = 1). Further, several studies focused on particular populations, such as street and shelter youths (n = 1) and adjudicated males (n = 1). Sampling methodologies of reviewed estimates included traditional random sampling (n = 1), nationally representative sampling (n = 2), convenience sampling (n = 1), respondent-driven sampling (n = 1), purposive sampling (n = 1), and use of census data (n = 2). Conclusion: Little research has estimated the prevalence of minor sex trafficking in the United States. The existing studies examine different areas and populations and use different categories to estimate the problem. The estimates reviewed here should be cited cautiously. Future research is needed on this important topic, including methodologies to produce more representative estimates of this hard-to-reach population

    Public policy and future mineral supplies

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    A widespread and pessimistic view of the availability of mineral commodities calls for strong government initiatives to ensure adequate future supplies. This article provides a more market oriented and optimistic perspective, one that focuses on production costs and prices rather than physical availability. It sees short-run shortages continuing to plague commodity markets in the future as in the past. Though painful while they last, these shortages are temporary and do not pose a serious long-run threat to human welfare. Moreover, even without government intervention, they self-correct. The sharply higher prices that they evoke create strong incentives that foster supply and curb demand. Potentially more serious are long-run shortages due to mineral depletion. Such shortages are often thought to be inevitable, a conclusion that flows directly from the physical view of depletion. For various reasons, we reject this view of depletion in favor of an economic view. The latter recognizes that depletion may create long-run shortages, but stresses that this need not be the case if new technology can continue to offset the cost-increasing effects of depletion in the future as it has in the past. The economic view also suggests that a list of mineral commodities most threatened by depletion can best be compiled using cumulative availability curves rather than the more common practice of calculating commodity life expectancies based on estimates of available stocks.<p>Validerad;2018;NivĂĄ 2;2018-08-08 (rokbeg)</p

    Designing a new science-policy communication mechanism for the UN Convention to Combat Desertification

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    The United Nations Convention to Combat Desertification (UNCCD) has lacked an efficient mechanism to access scientific knowledge since entering into force in 1996. In 2011 it decided to convene an Ad Hoc Working Group on Scientific Advice (AGSA) and gave it a unique challenge: to design a new mechanism for science-policy communication based on the best available scientific evidence. This paper outlines the innovative 'modular mechanism' which the AGSA proposed to the UNCCD in September 2013, and how it was designed. Framed by the boundary organization model, and an understanding of the emergence of a new multi-scalar and polycentric style of governing, the modular mechanism consists of three modules: a Science-Policy Interface (SPI); an international self-governing and self-organizing Independent Non-Governmental Group of Scientists; and Regional Science and Technology Hubs in each UNCCD region. Now that the UNCCD has established the SPI, it is up to the worldwide scientific community to take the lead in establishing the other two modules. Science-policy communication in other UN environmental conventions could benefit from three generic principles corresponding to the innovations in the three modules-joint management of science-policy interfaces by policy makers and scientists; the production of synthetic assessments of scientific knowledge by autonomous and accountable groups of scientists; and multi-scalar and multi-directional synthesis and reporting of knowledge

    GLORIA - A globally representative hyperspectral in situ dataset for optical sensing of water quality

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    The development of algorithms for remote sensing of water quality (RSWQ) requires a large amount of in situ data to account for the bio-geo-optical diversity of inland and coastal waters. The GLObal Reflectance community dataset for Imaging and optical sensing of Aquatic environments (GLORIA) includes 7,572 curated hyperspectral remote sensing reflectance measurements at 1 nm intervals within the 350 to 900 nm wavelength range. In addition, at least one co-located water quality measurement of chlorophyll a, total suspended solids, absorption by dissolved substances, and Secchi depth, is provided. The data were contributed by researchers affiliated with 59 institutions worldwide and come from 450 different water bodies, making GLORIA the de-facto state of knowledge of in situ coastal and inland aquatic optical diversity. Each measurement is documented with comprehensive methodological details, allowing users to evaluate fitness-for-purpose, and providing a reference for practitioners planning similar measurements. We provide open and free access to this dataset with the goal of enabling scientific and technological advancement towards operational regional and global RSWQ monitoring

    The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

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    This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics
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