5,357 research outputs found
RXJ0123.4-7321, a Be/X-ray binary in the wing of the SMC
To confirm faint Be/X-ray binary candidates from the XMM-Newton survey of the
Small Magellanic Cloud, we searched for X-ray outbursts in archival ROSAT
observations. We found that RXJ0123.4-7321 was much brighter when detected with
ROSAT than seen 16 years later by XMM-Newton. We analysed the ROSAT
observations and the OGLE I-band light curve of the optical counterpart to
investigate the nature of the system. High long-term variability in the X-ray
flux of a factor of ~150 was found between the ROSAT and XMM-Newton detections,
indicating strong outburst activity during the ROSAT observations. The I-band
light curve reveals long-term variability and regular outbursts with a period
of (119.9+-2.5) days indicating the orbital period of the binary system. The
large X-ray flux variations and the properties of the optical counterpart
confirm RXJ0123.4-7321 as a new Be/X-ray binary in the wing of the Small
Magellanic Cloud.Comment: 5 pages, 8 figures, accepted for publication in A&
Reliability measurement during software development
During the development of data base software for a multi-sensor tracking system, reliability was measured. The failure ratio and failure rate were found to be consistent measures. Trend lines were established from these measurements that provided good visualization of the progress on the job as a whole as well as on individual modules. Over one-half of the observed failures were due to factors associated with the individual run submission rather than with the code proper. Possible application of these findings for line management, project managers, functional management, and regulatory agencies is discussed. Steps for simplifying the measurement process and for use of these data in predicting operational software reliability are outlined
Providence River sediment erosion analysis
Issued as final repor
Winter Home Range and Habitat Use of the Virginia Northern Flying Squirrel (Glaucomys sabrinus fuscus)
We radio-tracked two male and one female Virginia northern flying squirrels (Glaucomys sabrinus fuscus) in the Allegheny Mountains of West Virginia at Snowshoe Mountain Resort, in winter 2003 and Canaan Valley National Wildlife Refuge in winter 2004, respectively, to document winter home range and habitat use in or near ski areas. Male home range size in the winter was larger than that reported for males during summer and fall, whereas the female home range we observed was smaller than those reported for summer and fall. However, winter habitat use was similar to summer and fall habitat use reported in other studies. Virginia northern flying squirrels foraged and denned in both red spruce (Picea rubens)-dominated forests and northern hardwood forests; however, selection of red spruce-dominated forests and open areas was greater than expected based on availability. Use of northern hardwood forest occurred less than expected based on availability. Male squirrels denned near, and routinely crossed, downhill ski slopes and unimproved roads during foraging bouts, whereas the female approached, but did not cross forest edges onto roads or trails
Swift J053041.9-665426, a new Be/X-ray binary pulsar in the Large Magellanic Cloud
We observed the newly discovered X-ray source Swift J053041.9-665426 in the
X-ray and optical regime to confirm its proposed nature as a high mass X-ray
binary. We obtained XMM-Newton and Swift X-ray data, along with optical
observations with the ESO Faint Object Spectrograph, to investigate the
spectral and temporal characteristics of Swift J053041.9-665426. The XMM-Newton
data show coherent X-ray pulsations with a period of 28.77521(10) s (1 sigma).
The X-ray spectrum can be modelled by an absorbed power law with photon index
within the range 0.76 to 0.87. The addition of a black body component increases
the quality of the fit but also leads to strong dependences of the photon
index, black-body temperature and absorption column density. We identified the
only optical counterpart within the error circle of XMM-Newton at an angular
distance of ~0.8 arcsec, which is 2MASS J05304215-6654303. We performed optical
spectroscopy from which we classify the companion as a B0-1.5Ve star. The X-ray
pulsations and long-term variability, as well as the properties of the optical
counterpart, confirm that Swift J053041.9-665426 is a new Be/X-ray binary
pulsar in the Large Magellanic Cloud.Comment: 10 pages, 8 figures, accepted for publication in A&
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Neurobiology of Positive Emotion Disruption in Neurodegenerative Disease
Alterations in emotion are common in neurodegenerative disease. Although often associated with diminished functioning, neurodegeneration of emotion circuits can lead to both losses and gains in a range of emotional functions, including reactivity, regulation, appraisal, and empathy. Most previous research in this area has focused on the impact of neurodegeneration on negative emotions; however, there has recently been increasing interest in the degree to which neurodegenerative diseases may also alter positive emotions. This chapter reviews how different neurodegenerative diseases (e.g., frontotemporal dementia, amyotrophic lateral sclerosis, and Alzheimer’s disease) impact positive emotions and the neural basis of positive emotion alterations. We will also discuss how decreases and increases in positive emotional reactivity can lead to specific behavioral symptoms in neurodegenerative disease and can impact patients’ family members and caregivers
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