12,021 research outputs found
A study of the leisure time activities, television viewing habits, and the expressed interests of a selected population of fifth grade children in connection with their studying of natural science by television
Thesis (Ed.M.)--Boston Universit
The alphaviruses: gene expression, replication, and evolution
The alphaviruses are a genus of 26 enveloped viruses that cause disease in humans and domestic animals. Mosquitoes or other hematophagous arthropods serve as vectors for these viruses. The complete sequences of the +/- 11.7-kb plus-strand RNA genomes of eight alphaviruses have been determined, and partial sequences are known for several others; this has made possible evolutionary comparisons between different alphaviruses as well as comparisons of this group of viruses with other animal and plant viruses. Full-length cDNA clones from which infectious RNA can be recovered have been constructed for four alphaviruses; these clones have facilitated many molecular genetic studies as well as the development of these viruses as expression vectors. From these and studies involving biochemical approaches, many details of the replication cycle of the alphaviruses are known. The interactions of the viruses with host cells and host organisms have been exclusively studied, and the molecular basis of virulence and recovery from viral infection have been addressed in a large number of recent papers. The structure of the viruses has been determined to about 2.5 nm, making them the best-characterized enveloped virus to date. Because of the wealth of data that has appeared, these viruses represent a well-characterized system that tell us much about the evolution of RNA viruses, their replication, and their interactions with their hosts. This review summarizes our current knowledge of this group of viruses
Housing production subsidies and neighborhood revitalization: New York City's ten-year capital plan for housing
This paper was presented at the conference "Policies to Promote Affordable Housing," cosponsored by the Federal Reserve Bank of New York and New York University's Furman Center for Real Estate and Urban Policy, February 7, 2002. It was part of Session 3: The Impact of Housing on People and Places.Housing - New York (N.Y.) ; Construction industry - New York (N.Y.) ; Housing subsidies ; Federal Reserve District, 2nd ; Housing - Finance
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Impossible Choices: How Workers Manage Unpredictable Scheduling Practices
A total of 16 percent of hourly workers and 36 percent of workers paid on some other basis experience unstable work schedules due to irregular, on-call, rotating, or split shifts, which negatively impact workers’ ability to manage family responsibilities, finances, and health. Primarily drawing on data from in-depth interviews conducted in Oregon in 2016, this study expands research on how workers navigate through “bad jobs” by exploring the ways in which they respond in an attempt to manage the individual impacts of precarious work arrangements. We found that workers respond to unpredictable scheduling in four ways: they acquiesce, self-advocate, quit, or directly oppose employers. Our findings highlight the “impossible choices” workers face as they negotiate prevalent, unpredictable work conditions, juggle work-life obligations, and struggle to remain employed. We conclude with fair week, work policy recommendations
The Weak Field Limit of the Magnetorotational Instability
We investigate the behavior of the magneto-rotational instability in the
limit of extremely weak magnetic field, i.e., as the ratio of ion cyclotron
frequency to orbital frequency (X) becomes small. Considered only in terms of
cold two-fluid theory, instability persists to arbitrarily small values of X,
and the maximum growth rate is of order the orbital frequency except for the
range m_e/m_i < |X| < 1, where it can be rather smaller. In this range, field
aligned with rotation (X > 0) produces slower growth than anti-aligned field (X
< 0). The maximum growth rate is generally achieved at smaller and smaller
wavelengths as |X| diminishes. When |X| < m_e/m_i, new unstable
"electromagnetic-rotational" modes appear that do not depend on the equilibrium
magnetic field. Because the most rapidly-growing modes have extremely short
wavelengths when |X| is small, they are often subject to viscous or resistive
damping, which can result in suppressing all but the longest wavelengths, for
which growth is much slower. We find that this sort of damping is likely to
curtail severely the frequently-invoked mechanism for cosmological magnetic
field growth in which a magnetic field seeded by the Biermann battery is then
amplified by the magneto-rotational instability. On the other hand, the small
|X| case may introduce interesting effects in weakly-ionized disks in which
dust grains carry most of the electric charge.Comment: 30 pages, including 4 figures; revised version resubmitted to Ap
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