995 research outputs found

    Nonparametric construction of probability maps under local stationarity

    Get PDF
    The environmental contamination risk can be evaluated in a specific area by approximating the probability that the pollutant under study exceeds a critical value. This issue requires the estimation of the distribution function involved, which can be addressed by applying the indicator kriging methodology or by approximating the sill of the variogram of the underlying indicator process. These approaches demand an appropriate characterization of the indicator variogram, which in turn requires a previous specification of the trend function, if the latter is suspected to be non-constant. Since accuracy of the results will be strongly dependent on the adequate approximation of both functions, we suggest proceeding in a different way to avoid these requirements. Thus, in the current paper, two kerneltype estimators are proposed, based on first approximating the distribution at the sampled sites and then obtaining a weighted average of the resulting values, to derive a valid estimator at each (sampled or unsampled) location. Consistency of the kernel approaches is proved under rather general conditions, such as local stationarity and the existence of derivatives up to the second order of the distribution function. Numerical studies have been carried out to illustrate the performance of our proposals when compared to those procedures requiring the approximation of the indicator variogram. In a final step, the kernel-type estimation of the distribution function has been applied to map the risk of contamination by arsenic in the Central Region of Portugal. With this aim, biomonitoring data of arsenic concentrations were used to detect those zones with higher risk of arsenic accumulation, which is mainly located on the northern part of the region.The authors would like to thank the helpful suggestions and comments from the Editor, the Associate Editor, and the Reviewers. The authors are also grateful to Karen J. Duncan for her contribution in the language revision. The first author’s work has been partially supported by the Spanish National Research and Development Program project [TEC2015-65353-R], by the European Regional Development Fund (ERDF), and by the Galician Regional Government under project GRC 2015/018 and under agreement for funding AtlantTIC (Atlantic Research Center for Information and Communication Technologies). The second author acknowledges financial support from the Portuguese Funds through FCT-“Fundação para a CiĂȘncia e a Tecnologia,” within the Project UID/MAT/00013/2013.info:eu-repo/semantics/publishedVersio

    Three-Dimensional FDTD Simulation of Biomaterial Exposure to Electromagnetic Nanopulses

    Full text link
    Ultra-wideband (UWB) electromagnetic pulses of nanosecond duration, or nanopulses, have been recently approved by the Federal Communications Commission for a number of various applications. They are also being explored for applications in biotechnology and medicine. The simulation of the propagation of a nanopulse through biological matter, previously performed using a two-dimensional finite difference-time domain method (FDTD), has been extended here into a full three-dimensional computation. To account for the UWB frequency range, a geometrical resolution of the exposed sample was 0.25mm0.25 mm, and the dielectric properties of biological matter were accurately described in terms of the Debye model. The results obtained from three-dimensional computation support the previously obtained results: the electromagnetic field inside a biological tissue depends on the incident pulse rise time and width, with increased importance of the rise time as the conductivity increases; no thermal effects are possible for the low pulse repetition rates, supported by recent experiments. New results show that the dielectric sample exposed to nanopulses behaves as a dielectric resonator. For a sample in a cuvette, we obtained the dominant resonant frequency and the QQ-factor of the resonator.Comment: 15 pages, 8 figure

    Problem gambling: a suitable case for social work?

    Get PDF
    Problem gambling attracts little attention from health and social care agencies in the UK. Prevalence surveys suggest that 0.6% of the population are problem gamblers and it is suggested that for each of these individuals, 10–17 other people, including children and other family members, are affected. Problem gambling is linked to many individual and social problems including: depression, suicide, significant debt, bankruptcy, family conflict, domestic violence, neglect and maltreatment of children and offending. This makes the issue central to social work territory. Yet, the training of social workers in the UK has consistently neglected issues of addictive behaviour. Whilst some attention has been paid in recent years to substance abuse issues, there has remained a silence in relation to gambling problems. Social workers provide more help for problems relating to addictions than other helping professions. There is good evidence that treatment, and early intervention for gambling problems, including psycho-social and public health approaches, can be very effective. This paper argues that problem gambling should be moved onto the radar of the social work profession, via inclusion on qualifying and post-qualifying training programmes and via research and dissemination of good practice via institutions such as the Social Care Institute for Excellence (SCIE). Keywords: problem gambling; addictive behaviour; socia

    Generic drug competition: The pharmaceutical industry “gaming” controversy

    Full text link
    Among American adults 20 years and older, 59 percent take at least one prescription drug on a regular basis. Unlike most branded drugs, which are generally drugs that have a trade name and are protected by a patent, off‐patent generic drugs make up approximately 90 percent of prescriptions annually filled in the United States; yet in 2017, generic drugs made up only 23 percent of total drug costs in the U.S. The U.S. Food and Drug Administration has taken the lead in encouraging increased competition in the nation’s prescription drug marketplace, most recently with its release of the agency’s Drug Competition Action Plan, but also with its regulatory guidance and enforcement efforts to eliminate “gaming” of the regulatory process by both branded and generic pharmaceutical manufacturers. Such “gaming” activities include “pay‐for‐delay” agreements involving financial compensation between branded and generic pharmaceutical manufacturers to forestall the emergence into the market of generic pharmaceuticals to compete against a formerly patent‐protected branded drug. A combination of new enabling legislation, federal judicial guidance, and agency regulatory activities show promise in encouraging increased competition in the prescription drug marketplace, with the American consumer the ultimate beneficiary of lower health care costs and improved overall personal health.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152498/1/basr12186_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152498/2/basr12186.pd

    The Governance of Corporate Responses to Climate Change: An International Comparison

    Get PDF
    In response to pressures from governments, investors, non-governmental organisations and other stakeholders, many large corporations have adopted a variety of carbon and energy management practices, taken action to reduce their emissions and set targets to reduce their greenhouse gas emissions. Using the case of international retailers, this article examines whether, and under what conditions, non-state actors might be capable of assuming the governance roles that have historically been played by national governments. This article concludes that external governance pressures can, if they are aligned, robust and of sufficient duration, have a significant influence on internal governance processes and on corporate strategies and actions. However, the specific actions that are taken by companies – in particular those that require significant capital investments – are constrained by the ‘business case’. That is, companies will generally only invest capital in situations when there is a clear financial case (i.e. where the benefits outweigh the costs, when the rate of return meets or exceeds company targets) for action. That is, the extent to which external governance pressures can force companies to take action, in particular challenging or transformative actions that go beyond the boundaries of the business case, is not at all clear. This is particularly the case if the business case weakens, or if the opportunities for incremental change are exhausted. In that context, the power of non-state actors to force them to consider radical changes in their business processes and their use of energy therefore seems to be very limited

    Corporation tax as a problem of MNC organisational circuits: The case for unitary taxation

    Get PDF
    The tax practices of multinational corporations have become a matter of significant public and political concern. The underlying issues are rooted in the capacity of multinational corporations (MNCs) to construct organisational circuits that shift where sales, revenue and profit are reported. This capacity in turn becomes a focus because of the way MNCs are treated as a series of separate entities, subject to the arm’s length principle. This has become a classic example of a system whose current form and consequences were not foreseen when the original principles were set out. The continued existence of that system owes more to specific interests and inertia than it does to the absence of a viable alternative. Unitary taxation based on formula apportionment clearly resolves the underlying issues and unitary taxation may well ultimately emerge as a new generalised basis for corporate taxation. However, for it to do so, the problems of the current system and the advantages of the alternative need to be more clearly understood within academia, business and on a societal basis. This paper is a contribution to such an understanding
    • 

    corecore