2,712 research outputs found
CRITERIA FOR SPECIES AND THEIR SUBDIVISIONS FROM THE POINT OF VIEW OF GENETICS
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73427/1/j.1749-6632.1943.tb31302.x.pd
The Magellan/IMACS Catalog of Optical Supernova Remnant Candidates in M83
We present a new optical imaging survey of supernova remnants in M83, using
data obtained with the Magellan I 6.5m telescope and IMACS instrument under
conditions of excellent seeing. Using the criterion of strong [S II] emission
relative to Halpha, we confirm all but three of the 71 SNR candidates listed in
our previous survey, and expand the SNR candidate list to 225 objects, more
than tripling the earlier sample. Comparing the optical survey with a new deep
X-ray survey of M83 with Chandra, we find 61 of these SNR candidates to have
X-ray counterparts. We also identify an additional list of 46 [O III] -selected
nebulae for follow-up as potential ejecta-dominated remnants, seven of which
have associated X-ray emission that makes them strong candidates. Some of the
other [O III]-bright objects could also be normal ISM-dominated supernova
remnants with shocks fast enough to doubly ionize oxygen, but with Halpha and
[S II] emission faint enough to have been missed. A few of these objects may
also be H II regions with abnormally high [O III] emission compared with the
majority of M83 H II regions, compact nebulae excited by young Wolf-Rayet
stars, or even background AGN. The supernova remnant Halpha luminosity function
in M83 is shifted a factor of ~ 4.5x higher than for M33 supernova remnants,
indicative of a higher mean ISM density in M83. We describe the search
technique used to identify the supernova remnant candidates and provide basic
information and finder charts for the objects.Comment: 40 pages, 15 figures, accepted for ApJ
How community resources mitigate the association between household poverty and the incidence of adverse childhood experiences
Strategic Command and Control: Redefining the Nuclear Threat, The Button: The Pentagon\u27s Strategic Command and Control System-Does It Work?
Observation of Tool Life of Micro End Mills
Prediction of mechanical machining tool life is an integral part of commercial manufacturing. Failure of micro end mills is still not well understood, and further work needs to be done to accurately predict tool life. The objective of this study is to observe the distribution of tool life for micro end mills under aggressive machining conditions without lubri-cation for 300-um-diameter micro end mills while machining 6061-T6 aluminum alloy. The average tool life was 3 to 7 times greater for the nanocrystalline diamond (NCD) coated micro end mills as compared with the uncoated (as received) tools. For both NCD coated and uncoated micro end mills the tool life increased as the cutting speed was in-creased from 32 to 48 m/min, suggesting the presence of a built-up-edge during machining. The variance in the tool life data was approximately an order of magnitude greater than what is expected in macro-scale machining
The Behavioral Analysis Interview: Clarifying the Practice, Theory and Understanding of its Use and Effectiveness
The Behavioral Analysis Interview (BAI) is the only questioning method that has been developed
specifically to help investigators sort those who are likely to be ‘guilty’ from those who are
not. In its typical application the BAI is a pre-interrogation interview that is used to focus interrogational
effort; however, it also can be used independently in order to circumscribe investigative
efforts in those cases in which there is a fixed and relatively large number of ‘suspects’. In this
paper an overview of the BAI process is provided and the findings and limitations of the extant
bodies of field and laboratory research on the BAI are discussed. The paper concludes with suggestions
to guide future research on the BAI
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