Nonlocal Gravity: Modified Poisson's Equation

The recent nonlocal generalization of Einstein's theory of gravitation reduces in the Newtonian regime to a nonlocal and nonlinear modification of Poisson's equation of Newtonian gravity. The nonlocally modified Poisson equation implies that nonlocality can simulate dark matter. Observational data regarding dark matter provide limited information about the functional form of the reciprocal kernel, from which the original nonlocal kernel of the theory must be determined. We study this inverse problem of nonlocal gravity in the linear domain, where the applicability of the Fourier transform method is critically examined and the conditions for the existence of the nonlocal kernel are discussed. This approach is illustrated via simple explicit examples for which the kernels are numerically evaluated. We then turn to a general discussion of the modified Poisson equation and present a formal solution of this equation via a successive approximation scheme. The treatment is specialized to the gravitational potential of a point mass, where in the linear regime we recover the Tohline-Kuhn approach to modified gravity.Comment: 27 pages, 4 figures; v2: minor improvements, accepted for publication in J. Math. Phy

The Study of the Pioneer Anomaly: New Data and Objectives for New Investigation

Radiometric tracking data from Pioneer 10 and 11 spacecraft has consistently indicated the presence of a small, anomalous, Doppler frequency drift, uniformly changing with a rate of ~6 x 10^{-9} Hz/s; the drift can be interpreted as a constant sunward acceleration of each particular spacecraft of a_P = (8.74 \pm 1.33) x 10^{-10} m/s^2. This signal is known as the Pioneer anomaly; the nature of this anomaly remains unexplained. We discuss the efforts to retrieve the entire data sets of the Pioneer 10/11 radiometric Doppler data. We also report on the recently recovered telemetry files that may be used to reconstruct the engineering history of both spacecraft using original project documentation and newly developed software tools. We discuss possible ways to further investigate the discovered effect using these telemetry files in conjunction with the analysis of the much extended Doppler data. We present the main objectives of new upcoming study of the Pioneer anomaly, namely i) analysis of the early data that could yield the direction of the anomaly, ii) analysis of planetary encounters, that should tell more about the onset of the anomaly, iii) analysis of the entire dataset, to better determine the anomaly's temporal behavior, iv) comparative analysis of individual anomalous accelerations for the two Pioneers, v) the detailed study of on-board systematics, and vi) development of a thermal-electric-dynamical model using on-board telemetry. The outlined strategy may allow for a higher accuracy solution for a_P and, possibly, will lead to an unambiguous determination of the origin of the Pioneer anomaly.Comment: 43 pages, 40 figures, 3 tables, minor changes before publicatio

“True Image Pictur’d”: Metaphor, Epistemology, and Shakespeare’s Sonnets

In this dissertation, I examine the influence of Pyrrhonist skepticism over Shakespeare’s sonnets. Unlike academic skepticism, which begins from a position of doubt, Pyrrhonist skepticism encourages an embrace of multiple perspectives that, according to Sextus Empiricus, leads first to a suspension of judgment and ultimately to a state of tranquility. The Pyrrhonian inflection of Shakespeare’s sonnets accounts for the pleasure and uncertainty they cultivate in readers. By offering readers multiple perspectives on a given issue, such as love or infidelity, Shakespeare’s sonnets demonstrate the instability of information, suggesting that such instability can be a source for pleasure. One essential tool for the uncertainty in the sonnets, I argue, is the figurative language they draw from a variety of fields and discourses. When these metaphors contradict one another, creating fragmented images in the minds of readers, they generate a unique aesthetic experience, which creates meaning that transcends the significance of any of the individual metaphors. In the first two chapters, I identify important contexts for Shakespeare’s sensitivity to the pliability of figurative language: Reformation-era religious tracts and pamphleteers’ debates about the value and function of the theater. In Chapter 3, I examine Shakespeare’s response to the Petrarchan tradition, arguing that he diverges from the sonneteers, who often use figurative language in an attempt to access and communicate stable truths. Shakespeare creates epistemological instability in sonnets both to the young man and to the dark lady, and, as I argue in Chapter 4, this similarity offers readers an opportunity to think beyond traditional divisions between the two sonnet subsequences

COMMENTARY: The Use of Focus Groups for Design and Implementation of Collaborative Environmental Administrative Programs: A Comparison of Two State-Level Processes in Ohio

Development and implementation of administrative programs are important steps in the process of change through public law and policy. These programs set the specific mechanisms that will be used to carry out the intent of the law or policy as best an agency can determine. Administrative personnel may involve the general public and stakeholders in program development and implementation in order to improve program design, increasingly used as part of collaborative environmental management strategies. This article examines the use of focus groups as a stakeholder participation method in collaborative program development and implementation processes in two different environmentally-oriented agency programs at the state level in Ohio—the Clean Ohio Revitalization Fund of the Ohio Department of Development, and the Ohio Coastal Resources Management Training Program of the Ohio Department of Natural Resources, NOAA, and the Ohio Sea Grant Program. The comparison confirms three categories of benefits in using focus groups: better program development and implementation through more in-depth and nuanced information from stakeholders, an enhanced administrative and civic capacity through development of a shared knowledge base, and an enhanced sense of legitimacy for the program among future program beneficiaries. The comparison also identified some constraints and challenges for using focus groups, including the importance of skilled facilitators with substantive knowledge of the environmental context of the program development process and the skills to resolve contentious stakeholder interactions when the processes are distributive in nature

Coastal Resources Management Training Needs Assessment: Strategies and Opportunities

The Old Woman Creek National Estuarine Research Reserve (OWC), Ohio Department of Natural Resources-Coastal Management Program (ODNRCMP), and Ohio Sea Grant College Program engaged the Great Lakes Environmental Finance Center (GLEFC) to aid them in developing a coastal resources management training initiative for Ohio coastal decision-makers. Coastal decision-maker professionals are expected to formulate effective strategies and apply interdisciplinary approaches to solving problems and policy issues that affect the environments of coastal regions. There are a number of professionals in a variety of occupations who make decisions regarding coastal and environmental policy issues. These individuals include those within the coastal resources management field, such as conservationists, planning professionals, and coastal regulatory officials, as well as individuals not directly within the field, such as local officials, state and federal agency staff, project managers, and staff from non-governmental, economic, and community development organizations

Coastal Resources Management Training Needs Assessment: Strategies and Opportunities

The Old Woman Creek National Estuarine Research Reserve (OWC), Ohio Department of Natural Resources-Coastal Management Program (ODNRCMP), and Ohio Sea Grant College Program engaged the Great Lakes Environmental Finance Center (GLEFC) to aid them in developing a coastal resources management training initiative for Ohio coastal decision-makers. Coastal decision-maker professionals are expected to formulate effective strategies and apply interdisciplinary approaches to solving problems and policy issues that affect the environments of coastal regions. There are a number of professionals in a variety of occupations who make decisions regarding coastal and environmental policy issues. These individuals include those within the coastal resources management field, such as conservationists, planning professionals, and coastal regulatory officials, as well as individuals not directly within the field, such as local officials, state and federal agency staff, project managers, and staff from non-governmental, economic, and community development organizations

Redshift determination in the X-ray band of gamma-ray bursts

If gamma-ray bursts originate in dense stellar forming regions, the interstellar material can imprint detectable absorption features on the observed X-ray spectrum. Such features can be detected by existing and planned X-ray satellites, as long as the X-ray afterglow is observed after a few minutes from the burst. If the column density of the interstellar material exceeds ~10^{23} cm^{-2} there exists the possibility to detect the K_alpha fluorescent iron line, which should be visible for more than one year, long after the X-ray afterglow continuum has faded away. Detection of these X-ray features will make possible the determination of the redshift of gamma-ray bursts even when their optical afterglow is severely dimmed by extinction.Comment: 15 pages with 5 figures. Submitted to Ap

Stationary axisymmetric exteriors for perturbations of isolated bodies in general relativity, to second order

Perturbed stationary axisymmetric isolated bodies, e.g. stars, represented by a matter-filled interior and an asymptotically flat vacuum exterior joined at a surface where the Darmois matching conditions are satisfied, are considered. The initial state is assumed to be static. The perturbations of the matching conditions are derived and used as boundary conditions for the perturbed Ernst equations in the exterior region. The perturbations are calculated to second order. The boundary conditions are overdetermined: necessary and sufficient conditions for their compatibility are derived. The special case of perturbations of spherical bodies is given in detail.Comment: RevTeX; 32 pp. Accepted by Phys. Rev. D. Added references and extra comments in introductio

Nano dust impacts on spacecraft and boom antenna charging

High rate sampling detectors measuring the potential difference between the main body and boom antennas of interplanetary spacecraft have been shown to be efficient means to measure the voltage pulses induced by nano dust impacts on the spacecraft body itself (see Meyer-Vernet et al, Solar Phys. 256, 463 (2009)). However, rough estimates of the free charge liberated in post impact expanding plasma cloud indicate that the cloud's own internal electrostatic field is too weak to account for measured pulses as the ones from the TDS instrument on the STEREO spacecraft frequently exceeding 0.1 V/m. In this paper we argue that the detected pulses are not a direct measure of the potential structure of the plasma cloud, but are rather the consequence of a transitional interruption of the photoelectron return current towards the portion of the antenna located within the expanding cloud

Coastal Training Market Analysis: Final Report

A market is emerging for policy makers in the area of coastal resources management. Individuals, as professionals or private citizens, are frequently called upon to make decisions regarding coastal environmental issues. The context in which they do so varies considerably; thus education and training in this topic area serves to heighten and expand the knowledge base of the coastal decision-maker