ABSTRACT
Two classes of rotating neutron stars-soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars-are magnetars, whose X-ray emission is powered by a very strong magnetic field (B approximately 10(15) G). SGRs occasionally become 'active', producing many short X-ray bursts. Extremely rarely, an SGR emits a giant flare with a total energy about a thousand times higher than in a typical burst. Here we report that SGR 1806-20 emitted a giant flare on 27 December 2004. The total (isotropic) flare energy is 2 x 10(46) erg, which is about a hundred times higher than the other two previously observed giant flares. The energy release probably occurred during a catastrophic reconfiguration of the neutron star's magnetic field. If the event had occurred at a larger distance, but within 40 megaparsecs, it would have resembled a short, hard gamma-ray burst, suggesting that flares from extragalactic SGRs may form a subclass of such bursts.
ABSTRACT
The association of hostility and coronary artery disease was evaluated in a case-control study of aircrew members who had been referred for coronary angiography on the basis of noninvasive tests or risk factor status. The asymptomatic status of the sample and the structured nature of the referral process minimize the methodologic problems normally associated with studies of patients undergoing angiography. Cases (n = 24) had some angiographic evidence of coronary artery disease, whereas controls (n = 25) were found to have no evidence of occlusion. An interaction was observed between smoking history and a measurement of hostility based on observations of the respondent's behavior during a standard interview. Among nonsmokers, cases had higher hostility scores than did controls (p = 0.004). This association was not present among smokers. Self-reported hostility did not discriminate cases from controls. These findings support the notion that hostility plays a role in the pathogenesis of coronary atherosclerosis and point to the potential importance of interactions between hostility and other risk factors.
Subject(s)
Coronary Angiography , Coronary Disease/psychology , Hostility , Adult , Case-Control Studies , Coronary Disease/diagnostic imaging , Humans , Male , Middle Aged , Military Personnel , Risk FactorsABSTRACT
Depression, as a primary or secondary illness, is a potentially devastating disorder that can significantly affect one's quality of life and, in its worst form, lead to suicide. Stress is an inherent aspect in the practice of dentistry and, allowed to grow unchecked, can lead to mental anguish and depression. However, effective coping strategies can neutralize the effect of stress and make the delivery of dental care an enjoyable experience. The majority of dentists have developed effective means of coping with professional stresses in a fashion that is consistent with other professionals and white-collar workers. Although dentists may become depressed, they do not seem to be drinking, divorcing, or committing suicide in numbers greater than the nonprofessional population. If dentists can learn to deal with their unique stresses, through either undergraduate or continuing dental education, then depression among practitioners could be noticeably reduced.
Subject(s)
Dentists , Depressive Disorder/diagnosis , Occupational Diseases/diagnosis , Adult , Depressive Disorder/classification , Depressive Disorder/therapy , Diagnosis, Differential , Humans , Male , Occupational Diseases/classification , Occupational Diseases/therapy , Self Care/psychologyABSTRACT
A single-subject reversal design was used to test the hypothesis that aerobic conditioning would elevate mood in seven clinically depressed persons. The hypothesis was confirmed for two subjects but not for the group as a whole. A reversal design does not appear suitable for this area of investigation.
