698 research outputs found

    Policies and Programs Affecting the Employment of People with Disabilities - Policy Brief

    Get PDF
    The purpose of this brief is to summarize the wide range of federal programs and government policies that influence the employment and program participation decisions of people with disabilities and current research initiatives related to these programs and policies. The brief is organized by the following types of programs, policies, and initiatives: • federal programs that provide cash assistance, in-kind transfers (e.g., health insurance) and education, training, and rehabilitation support based on disability status and/or other characteristics (e.g., family structure); • federal tax policies that provide credits either directly to individuals with disabilities or to employers as an incentive to hire a person with a disability; • other employment-related programs and public policies that provide accommodation support and work incentives for people with disabilities; • recent policy changes that affect people with disabilities; and • some of the current research initiatives related to federal programs, tax policies, other employment programs and policies, and recent policy changes. We conclude with a summary of our program, policy, and research scan. This publication is based on The Economics of Policies and Programs Affecting the Employment of People with Disabilities, which provides a more comprehensive review of the policies and programs discussed here (as well as others) and analyzes the employment effects of these policies and programs within an economic framework

    The Economics of Policies and Programs Affecting the Employment of People with Disabilities

    Get PDF
    Over the last several decades, there has been a movement toward the inclusion of people with disabilities in mainstream social institutions. The 1990 Americans with Disabilities Act (ADA), which supports the full participation of people with disabilities in society and mainstream institutions, illustrates the shift in attitudes toward people with disabilities. Rather than being perceived as having a social or medical problem, individuals with disabilities are increasingly viewed as people with challenges that can be solved if appropriate policies and supports are available for addressing them

    An engineered Tetrahymena tRNA(Gln) for in vivo incorporation of unnatural amino acids into proteins by nonsense suppression

    Get PDF
    A new tRNA, THG73, has been designed and evaluated as a vehicle for incorporating unnatural amino acids site-specifically into proteins expressed in vivo using the stop codon suppression technique. The construct is a modification of tRNAGln(CUA) from Tetrahymena thermophila, which naturally recognizes the stop codon UAG. Using electrophysiological studies of mutations at several sites of the nicotinic acetylcholine receptor, it is established that THG73 represents a major improvement over previous nonsense suppressors both in terms of efficiency and fidelity of unnatural amino acid incorporation. Compared with a previous tRNA used for in vivo suppression, THG73 is as much as 100-fold less likely to be acylated by endogenous synthetases of the Xenopus oocyte. This effectively eliminates a major concern of the in vivo suppression methodology, the undesirable incorporation of natural amino acids at the suppression site. In addition, THG73 is 4-10-fold more efficient at incorporating unnatural amino acids in the oocyte system. Taken together, these two advances should greatly expand the range of applicability of the in vivo nonsense suppression methodology

    Characteristics of Mountain Lion Bed, Cache and Kill Sites In Northeastern Oregon

    Get PDF
    We described mountain lion (Puma concolor) habitat characteristics during two studies in the same area of northeastern Oregon during the 1990s. In the first study (1992-1994) we evaluated micro-habitat features associated with 61 diurnal bed sites that were not associated with kills. We used similar techniques in the second study (1996- 1998) to evaluate habitat features at 79 cache sites near lion-killed prey. A dog was used to find 93% of the diurnal bed sites. Radio telemetry triangulation was used in the second study. Characteristics of diurnal bed sites and cache sites were compared with random habitat plots. Rock structure and downed logs were identified as important habitat components at diurnal bed sites. Canopy cover at cache sites was significantly higher than at random sites. Cache sites also were associated with rock structure, but not to the same degree as diurnal bed sites. In both studies mountain lions used sites in close proximity to habitat edges more frequently than expected based on random plots. Understanding the similarities and differences of habitat use at diurnal bed, cache and kill sites sheds light on the ecological adaptation of mountain lions to the multiple environmental influences and disturbances of managed forests

    Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111

    Full text link
    We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 111 between 2004 and 2010 at X-ray (2.4--10 keV), optical (R band), and radio (14.5, 37, and 230 GHz) wave bands, as well as multi-epoch imaging with the Very Long Baseline Array (VLBA) at 43 GHz. Over the six years of observation, significant dips in the X-ray light curve are followed by ejections of bright superluminal knots in the VLBA images. This shows a clear connection between the radiative state near the black hole, where the X-rays are produced, and events in the jet. The X-ray continuum flux and Fe line intensity are strongly correlated, with a time lag shorter than 90 days and consistent with zero. This implies that the Fe line is generated within 90 light-days of the source of the X-ray continuum. The power spectral density function of X-ray variations contains a break, with steeper slope at shorter timescales. The break timescale of 13 (+12,-6) days is commensurate with scaling according to the mass of the central black hole based on observations of Seyfert galaxies and black hole X-ray binaries (BHXRBs). The data are consistent with the standard paradigm, in which the X-rays are predominantly produced by inverse Compton scattering of thermal optical/UV seed photons from the accretion disk by a distribution of hot electrons --- the corona --- situated near the disk. Most of the optical emission is generated in the accretion disk due to reprocessing of the X-ray emission. The relationships that we have uncovered between the accretion disk and the jet in 3C 111, as well as in the FR I radio galaxy 3C 120 in a previous paper, support the paradigm that active galactic nuclei and Galactic BHXRBs are fundamentally similar, with characteristic time and size scales proportional to the mass of the central black holeComment: Accepted for publication in ApJ. 18 pages, 17 figures, 11 tables (full machine readable data-tables online in ApJ website

    Individualization as driving force of clustering phenomena in humans

    Get PDF
    One of the most intriguing dynamics in biological systems is the emergence of clustering, the self-organization into separated agglomerations of individuals. Several theories have been developed to explain clustering in, for instance, multi-cellular organisms, ant colonies, bee hives, flocks of birds, schools of fish, and animal herds. A persistent puzzle, however, is clustering of opinions in human populations. The puzzle is particularly pressing if opinions vary continuously, such as the degree to which citizens are in favor of or against a vaccination program. Existing opinion formation models suggest that "monoculture" is unavoidable in the long run, unless subsets of the population are perfectly separated from each other. Yet, social diversity is a robust empirical phenomenon, although perfect separation is hardly possible in an increasingly connected world. Considering randomness did not overcome the theoretical shortcomings so far. Small perturbations of individual opinions trigger social influence cascades that inevitably lead to monoculture, while larger noise disrupts opinion clusters and results in rampant individualism without any social structure. Our solution of the puzzle builds on recent empirical research, combining the integrative tendencies of social influence with the disintegrative effects of individualization. A key element of the new computational model is an adaptive kind of noise. We conduct simulation experiments to demonstrate that with this kind of noise, a third phase besides individualism and monoculture becomes possible, characterized by the formation of metastable clusters with diversity between and consensus within clusters. When clusters are small, individualization tendencies are too weak to prohibit a fusion of clusters. When clusters grow too large, however, individualization increases in strength, which promotes their splitting.Comment: 12 pages, 4 figure

    Disk-Jet Connection in the Radio Galaxy 3C 120

    Get PDF
    We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 120 between 2002 and 2007 at X-ray, optical, and radio wave bands, as well as imaging with the Very Long Baseline Array (VLBA). Over the 5 yr of observation, significant dips in the X-ray light curve are followed by ejections of bright superluminal knots in the VLBA images. Consistent with this, the X-ray flux and 37 GHz flux are anti-correlated with X-ray leading the radio variations. This implies that, in this radio galaxy, the radiative state of accretion disk plus corona system, where the X-rays are produced, has a direct effect on the events in the jet, where the radio emission originates. The X-ray power spectral density of 3C 120 shows a break, with steeper slope at shorter timescale and the break timescale is commensurate with the mass of the central black hole based on observations of Seyfert galaxies and black hole X-ray binaries. These findings provide support for the paradigm that black hole X-ray binaries and active galactic nuclei are fundamentally similar systems, with characteristic time and size scales linearly proportional to the mass of the central black hole. The X-ray and optical variations are strongly correlated in 3C 120, which implies that the optical emission in this object arises from the same general region as the X-rays, i.e., in the accretion disk-corona system. We numerically model multi-wavelength light curves of 3C 120 from such a system with the optical-UV emission produced in the disk and the X-rays generated by scattering of thermal photons by hot electrons in the corona. From the comparison of the temporal properties of the model light curves to that of the observed variability, we constrain the physical size of the corona and the distances of the emitting regions from the central BH.Comment: Accepted for publication in the Astrophysical Journal. 28 pages, 21 figures, 2 table
    • …
    corecore