267 research outputs found

    An Analysis of Potential Tax Incentives to Increase Charitable Giving in Puerto Rico

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    Compares options for improving tax incentives for charitable giving, including lifting the ceiling on deductions as a percentage of adjusted gross income, and estimated effects on nonprofits in Puerto Rico, where average giving is high relative to AGI

    Achieving Greater Homeland Security: Who Should Pay, and How?

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    The terrorist attacks of September 11, 2001 in the United States have broadened the public sector’s role in providing “protective goods and services” to include homeland security in addition to national security and public safety (e.g. police and fire protection). Although it is acknowledged that the federal government has a clear responsibility for taking the lead in shaping homeland security policies, the provision of greater homeland security involves significant participation by state and local governments, and the private sector, in addition to the national government.This paper briefly summarizes why private markets are likely to under-invest in homeland security, leading to a need for public action. It provides an overview of both the range of budgetary and non-budgetary tools used by the United States (U.S.) federal government to “finance” the provision of homeland security, and the budgetary and non-budgetary cost of these federal actions. The paper also identifies and discusses some of the principle challenges faced in ensuring federal homeland security dollars are “well-spent.” While the analysis focuses on the United States, the tools of government employed are applicable to all sovereign nations

    Academic Rhetoric in the Policy Arena: The Case of Capital Gains Taxation

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    We investigate possible explanations for the rhetorical gap that divides producers and influential consumers of economic knowledge, academic economists and policymakers, respectively. We argue that economics lacks a developed theory of how academic research influences political decision making. This theoretical lacuna and the nature of the rhetorical gap have consequences for the effectiveness of academic ideas. We sketch three models, and argue for a process analysis as superior to conventional accounts. The debate on taxation of capital gains is our case study.Economics; Economists; Taxation

    The Radial Extent and Warp of the Ionized Galactic Disk. I. A VLBA Survey of Extragalactic Sources Toward the Anticenter

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    We report multifrequency Very Long Baseline Array observations of twelve active galactic nuclei seen toward the Galactic anticenter. All of the sources are at |b| < 10 degrees and seven have |b| < 0.5 degrees. Our VLBA observations can detect an enhancement in the angular broadening of these sources due to an extended H II disk, if the orientation of the H II disk in the outer Galaxy is similar to that of the H I disk. Such an extended H II disk is suggested by the C IV absorption in a quasar's spectrum, the appearance of H I disks of nearby spiral galaxies, and models of Ly-alpha cloud absorbers and the Galactic fountain. We detect eleven of the twelve sources at one or more frequencies; nine of the sources are compact and suitable for an angular broadening analysis. A preliminary analysis of the observed angular diameters suggests that the H II disk does not display considerable warping or flaring and does not extend to large Galactocentric distances (R >~ 100 kpc). A companion paper (Lazio & Cordes 1997) combines these observations with those in the literature and presents a more comprehensive analysis.Comment: 19 pages, LaTeX2e with AASTeX macro aaspp4, accepted for publication in ApJS, Vol. 115, 1998 April; Figures 1, 3, and 4 included, for figures of individual sources see http://astrosun.tn.cornell.edu/students/lazio/Anticenter/anticenterI.htm

    Angular Broadening of Intraday Variable AGN. II. Interstellar and Intergalactic Scattering

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    We analyze a sample of 58 multi-wavelength, Very Long Baseline Array observations of active galactic nuclei (AGN) to determine their scattering properties. Approximately 75% of the sample consists of AGN that exhibit centimeter-wavelength intraday variability (interstellar scintillation) while the other 25% do not show intraday variability. We find that interstellar scattering is measurable for most of these AGN, and the typical broadening diameter is 2 mas at 1 GHz. We find that the scintillating AGN are typically at lower Galactic latitudes than the non-scintillating AGN, consistent with the scenario that intraday variability is a propagation effect from the Galactic interstellar medium. The magnitude of the inferred interstellar broadening measured toward the scintillating AGN, when scaled to higher frequencies, is comparable to the diameters inferred from analyses of the light curves for the more well-known intraday variable sources. However, we find no difference in the amount of scattering measured toward the scintillating versus non-scintillating AGN. A consistent picture is one in which the scintillation results from localized regions ("clumps") distributed throughout the Galactic disk, but which individually make little contribution to the angular broadening. Of the 58 AGN observed, 37 (64%) have measured redshifts. At best, a marginal trend is found for scintillating (non-scintillating) AGN to have smaller (larger) angular diameters at higher redshifts. We also use our observations to try to constrain the possibility of intergalactic scattering. While broadly consistent with the scenario of a highly turbulent intergalactic medium, our observations do not place significant constraints on its properties.Comment: 13 pages, 4 figures; AASTeX format; ApJ in pres

    The Microarcsecond Sky and Cosmic Turbulence

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    Radio waves are imprinted with propagation effects from ionized media through which they pass. Owing to electron density fluctuations, compact sources (pulsars, masers, and compact extragalactic sources) can display a wide variety of scattering effects. These scattering effects, particularly interstellar scintillation, can be exploited to provide *superresolution*, with achievable angular resolutions (<~ 1 microarcsecond) far in excess of what can be obtained by very long baseline interferometry on terrestrial baselines. Scattering effects also provide a powerful sub-AU probe of the microphysics of the interstellar medium, potentially to spatial scales smaller than 100 km, as well as a tracer of the Galactic distribution of energy input into the interstellar medium through a variety of integrated measures. Coupled with future gamma-ray observations, SKA observations also may provide a means of detecting fainter compact gamma-ray sources. Though it is not yet clear that propagation effects due to the intergalactic medium are significant, the SKA will either detect or place stringent constraints on intergalactic scattering.Comment: 20 pages, 8 figures in 8 PostScript files, to appear in "Science with the Square Kilometer Array," eds. C. Carilli and S. Rawlings, New Astronomy Reviews (Elsevier: Amsterdam

    Genesis Lunar Outpost: Program/Requirements Document for an Early Stage Lunar Outpost

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    Second document in a series from the Space Architecture Design Group. Developed under the first year of a three-year grant from NASA, the program covers humans factors, environment-behavior, structural, construction processes, life-system and related needs for an 8-12 person lunar base for assignments lasting up to 20 months. The program includes sections on base master planning, base operations, command center, technical support habitat and all related design requirements.https://dc.uwm.edu/caupr_mono/1053/thumbnail.jp

    Surveying the Dynamic Radio Sky with the Long Wavelength Demonstrator Array

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    This paper presents a search for radio transients at a frequency of 73.8 MHz (4 m wavelength) using the all-sky imaging capabilities of the Long Wavelength Demonstrator Array (LWDA). The LWDA was a 16-dipole phased array telescope, located on the site of the Very Large Array in New Mexico. The field of view of the individual dipoles was essentially the entire sky, and the number of dipoles was sufficiently small that a simple software correlator could be used to make all-sky images. From 2006 October to 2007 February, we conducted an all-sky transient search program, acquiring a total of 106 hr of data; the time sampling varied, being 5 minutes at the start of the program and improving to 2 minutes by the end of the program. We were able to detect solar flares, and in a special-purpose mode, radio reflections from ionized meteor trails during the 2006 Leonid meteor shower. We detected no transients originating outside of the solar system above a flux density limit of 500 Jy, equivalent to a limit of no more than about 10^{-2} events/yr/deg^2, having a pulse energy density >~ 1.5 x 10^{-20} J/m^2/Hz at 73.8 MHz for pulse widths of about 300 s. This event rate is comparable to that determined from previous all-sky transient searches, but at a lower frequency than most previous all-sky searches. We believe that the LWDA illustrates how an all-sky imaging mode could be a useful operational model for low-frequency instruments such as the Low Frequency Array, the Long Wavelength Array station, the low-frequency component of the Square Kilometre Array, and potentially the Lunar Radio Array.Comment: 20 pages; accepted for publication in A
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