2,890 research outputs found
Pretty Little Rainbow : An Indian Love Song
https://digitalcommons.library.umaine.edu/mmb-vp/2403/thumbnail.jp
Shock Speed, Cosmic Ray Pressure, and Gas Temperature in the Cygnus Loop
Upper limits on the shock speeds in supernova remnants can be combined with
post-shock temperatures to obtain upper limits on the ratio of cosmic ray to
gas pressure (P_CR / P_G) behind the shocks. We constrain shock speeds from
proper motions and distance estimates, and we derive temperatures from X-ray
spectra. The shock waves are observed as faint H-alpha filaments stretching
around the Cygnus Loop supernova remnant in two epochs of the Palomar
Observatory Sky Survey (POSS) separated by 39.1 years. We measured proper
motions of 18 non-radiative filaments and derived shock velocity limits based
on a limit to the Cygnus Loop distance of 576 +/- 61 pc given by Blair et al.
for a background star. The PSPC instrument on-board ROSAT observed the X-ray
emission of the post-shock gas along the perimeter of the Cygnus Loop, and we
measure post-shock electron temperature from spectral fits. Proper motions
range from 2.7 arcseconds to 5.4 arcseconds over the POSS epochs and post-shock
temperatures range from kT ~ 100-200 eV. Our analysis suggests a cosmic ray to
post-shock gas pressure consistent with zero, and in some positions P_CR is
formally smaller than zero. We conclude that the distance to the Cygnus Loop is
close to the upper limit given by the distance to the background star and that
either the electron temperatures are lower than those measured from ROSAT PSPC
X-ray spectral fits or an additional heat input for the electrons, possibly due
to thermal conduction, is required.Comment: Submitted to ApJ, 7 color figure
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Lower Visual Avoidance in Dementia Patients Is Associated with Greater Psychological Distress in Caregivers.
Caring for a spouse with dementia can lead to increased health problems in caregivers. The present study examined whether patient deficits in visual avoidance, a common form of emotion regulation, are related to greater psychological distress in caregivers. Participants were 43 Alzheimer disease (AD) patients, 43 behavioral variant frontotemporal dementia (bvFTD) patients, and their spousal caregivers. Patient visual avoidance (e.g., gaze aversion) was measured using behavioral coding of head, body, and eye position while viewing a disgusting film. Caregiver psychological distress was measured using a standard self-report symptom inventory. Lower use of visual avoidance by patients was associated with greater psychological distress in their caregivers. This relationship was partially mediated by patient overall emotional functioning (as reported by caregivers), such that patients with less visual avoidance were seen as having worse emotional functioning, which in turn related to greater caregiver psychological distress. Dementia diagnosis moderated this effect, with diminished patient visual avoidance particularly detrimental to psychological distress of bvFTD caregivers. Findings suggest that the use of visual avoidance may serve as a marker of overall emotional functioning in patients and that preservation of this emotion regulatory behavior may help reduce the negative effects of caregiving
Vegetation forest island edges: A preliminary report
As the original native forest has been dissected by roads and replaced by farms or towns, the amount of forest edge relative to the area of forest interior has greatly increased. Today forest edge communities are widespread in many man-modified landscapes. However, the role the edge community plays in the regional landscape, and the extent of and variation in the edge community are relatively undefined. The purpose of this study is to determine the nature of forest edge communities. The specific objectives of the study are to: (1) quantitatively survey and assess the forest edge community; (2) determine how forest edge vegetation differs from that of the forest interior; (3) determine if the directional aspect affects the edge vegetation and (4) present guidelines and suggestions for the management of forest habitat islands, particularly as they relate to the edge community
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Emotion regulation via visual avoidance: Insights from neurological patients.
Visual avoidance of unpleasant stimuli (i.e., strategic positioning of eyes, head and torso away from an environmental stimulus) is a common attentional control behavior that may down-regulate emotion by reducing visual input. Despite its ubiquity, relatively little is known about how visual avoidance is affected by neurological diseases that impact neural circuits involved in emotional functioning. We examined visual avoidance in 56 behavioral variant frontotemporal dementia (bvFTD) patients, 43 Alzheimer's disease (AD) patients, and 34 healthy controls. Participants came to our laboratory and viewed an extremely disgusting film clip while visual avoidance was measured using behavioral coding of head, body, and eye position. Controlling for differences in cognitive functioning, bvFTD patients were less likely to engage in visual avoidance behaviors than both AD patients and healthy controls. Additional analyses revealed that diminished visual avoidance in this task was associated with lower levels of real-world emotion regulation but not with emotion reactivity as reported by the primary caregiver
Sweet Kentucky Sue
https://digitalcommons.library.umaine.edu/mmb-vp/5340/thumbnail.jp
In-flight calibration of the Herschel-SPIRE instrument
SPIRE, the Spectral and Photometric Imaging REceiver, is the Herschel Space Observatory's submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 μm, and an imaging Fourier-transform spectrometer (FTS) covering 194–671 μm (447-1550 GHz). In this paper we describe the initial approach taken to the absolute calibration of the SPIRE instrument using a combination of the emission from the Herschel telescope itself and the modelled continuum emission from solar system objects and other astronomical targets. We present the photometric, spectroscopic and spatial accuracy that is obtainable in data processed through the “standard” pipelines. The overall photometric accuracy at this stage of the mission is estimated as 15% for the photometer and between 15 and 50% for the spectrometer. However, there remain issues with the photometric accuracy of the spectra of low flux sources in the longest wavelength part of the SPIRE spectrometer band. The spectrometer wavelength accuracy is determined to be better than 1/10th of the line FWHM. The astrometric accuracy in SPIRE maps is found to be 2 arcsec when the latest calibration data are used. The photometric calibration of the SPIRE instrument is currently determined by a combination of uncertainties in the model spectra of the astronomical standards and the data processing methods employed for map and spectrum calibration. Improvements in processing techniques and a better understanding of the instrument performance will lead to the final calibration accuracy of SPIRE being determined only by uncertainties in the models of astronomical standards
Label-free detection of anticancer drug paclitaxel in living cells by confocal Raman microscopy
Confocal Raman microscopy, a non-invasive, label-free, and high spatial resolution imaging technique is employed to trace the anticancer drug paclitaxel in living Michigan Cancer Foundation-7 (MCF-7) cells. The Raman images were treated by K-mean cluster analysis to detect the drug in cells. Distribution of paclitaxel in cells is verified by calculating the correlation coefficient between the reference spectrum of the drug and the whole Raman image spectra. A time dependent gradual diffusion of paclitaxel all over the cell is observed suggesting a complementary picture of the pharmaceutical action of this drug based on rapid binding of free tubulin to crystallized paclitaxel. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794871
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