4,439 research outputs found
HD101584: Circumstellar characteristics and evolutionary status
We have performed a study of the characteristics of the circumstellar
environment of the binary object HD101584, that provides information on a
likely evolutionary scenario. We have obtained and analysed ALMA observations,
complemented with observations using APEX, of a large number of molecular
lines. An analysis of the spectral energy distribution has also been performed.
Emissions from 12 molecular species (not counting isotopologues) have been
observed, and most of them mapped with angular resolutions in the range 0.1" to
0.6". Four circumstellar components are identified: i) a central compact source
of size 0.15", ii) an expanding equatorial density enhancement (a flattened
density distribution in the plane of the orbit) of size 3", iii) a bipolar
high-velocity outflow (150 km/s), and iv) an hourglass structure. The outflow
is directed almost along the line of sight. There is evidence of a second
bipolar outflow. The mass of the circumstellar gas is 0.5[D/1 kpc]^2 Msun,
about half of it lies in the equatorial density enhancement. The dust mass is
0.01[D/1 kpc]^2 Msun, and a substantial fraction of this is in the form of
large-sized, up to 1 mm, grains. The estimated kinetic age of the outflow is
770[D/1 kpc] yr. The kinetic energy and the scalar momentum of the accelerated
gas are estimated to be 7x10^(45)[D/1 kpc]^2 erg and 10^(39)[D/1 kpc]^2 g cm/s,
respectively. We provide good evidence that the binary system HD101584 is in a
post-common-envelope-evolution phase, that ended before a stellar merger.
Isotope ratios combined with stellar mass estimates suggest that the primary
star's evolution was terminated already on the first red giant branch (RGB).
Most of the energy required to drive the outflowing gas was probably released
when material fell towards the companion.Comment: Accepted for publication in A&
Comparing drug-using behaviors among high school graduates entering military service, college, and civilian employment
https://deepblue.lib.umich.edu/bitstream/2027.42/137885/1/occ42.pd
The Monitoring the Future 8th Grade Panel Survey Data: Sample Design, Adjustments for Panel Attrition Biases, and Assessment of Measurement Bias
https://deepblue.lib.umich.edu/bitstream/2027.42/137871/1/occ55.pd
Revisiting marriage effects on substance use among young adults
https://deepblue.lib.umich.edu/bitstream/2027.42/137855/1/occ68.pd
Substance use and academic success: Results from three longitudinal panels, including analyses of adjustments for panel attrition
https://deepblue.lib.umich.edu/bitstream/2027.42/137861/1/occ62.pd
Education-drug use relationships: An examination of racial/ethnic subgroups
https://deepblue.lib.umich.edu/bitstream/2027.42/137857/1/occ66.pd
Fabrication of magnetocaloric La(Fe,Si) thick films
La(Fe,Si)-based compounds are considered to be very promising
magnetocaloric materials for magnetic refrigeration applications. Many studies
have focused on this material family but only in bulk form. In this paper, we
report the fabrication of thick films of La(Fe,Si), both with and
without post-hydriding. These films exhibit magnetic and structural properties
comparable to those of bulk materials. We also observe that the ferromagnetic
phase transition has a negative thermal hysteresis, a phenomenon not previously
found in this material but which may have its origins in the availability of a
strain energy reservoir, as in the cases of other materials in which negative
thermal hysteresis has been found. Here, it appears that the substrate acts to
store strain energy. Our exploratory study demonstrates the viability of thick
films of the La(Fe,Si) phase and motivates further work in the area,
while showing that additional perspectives can be gained from reducing the
dimensionality of magnetocaloric materials in which the magneto-volume effect
is large.Comment: 16 pages, 3 figure
Genetic Structure of American Black Bears in the Desert Southwest of North America
Abstract American black bears (Ursus americanus) have recolonized parts of their former range in the Trans-Pecos region of western Texas after a \u3e40-year absence. Assessment of genetic variation, structuring, gene flow, and dispersal among bear populations along the borderlands of Mexico and Texas is important to gain a better understanding of recolonization by large carnivores. We evaluated aspects of genetic diversity and gene flow for 6 sampling areas of black bears in southwestern North America using genotypic data from 7 microsatellite loci. Our results indicated that genetic diversity generally was high in the metapopulation of black bears in northern Mexico and western Texas. The episodic gene flow occurring via desert corridors between populations in northern Mexico and those in western Texas has permitted the establishment of only moderate levels of genetic structuring. Bayesian clustering analyses and assignment testing depicted the presence of 3 subpopulations among our 6 sampling areas and attested to the generally panmictic nature of bear populations in the borderlands region. The potentially ephemeral nature of the small populations in western Texas and genotypic characteristics of bears recolonizing these habitats attest to the importance of linkages along this portion of the borderlands of the United States and Mexico to effectively conserve and manage the species in this part of its range
The future of social is personal: the potential of the personal data store
This chapter argues that technical architectures that facilitate the longitudinal, decentralised and individual-centric personal collection and curation of data will be an important, but partial, response to the pressing problem of the autonomy of the data subject, and the asymmetry of power between the subject and large scale service providers/data consumers. Towards framing the scope and role of such Personal Data Stores (PDSes), the legalistic notion of personal data is examined, and it is argued that a more inclusive, intuitive notion expresses more accurately what individuals require in order to preserve their autonomy in a data-driven world of large aggregators. Six challenges towards realising the PDS vision are set out: the requirement to store data for long periods; the difficulties of managing data for individuals; the need to reconsider the regulatory basis for third-party access to data; the need to comply with international data handling standards; the need to integrate privacy-enhancing technologies; and the need to future-proof data gathering against the evolution of social norms. The open experimental PDS platform INDX is introduced and described, as a means of beginning to address at least some of these six challenges
Analyses showing how religiosity, social activities, and drug-related beliefs mediate relationships between post-high school experiences and substance use
https://deepblue.lib.umich.edu/bitstream/2027.42/137877/1/occ50.pd
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