159 research outputs found
Graviton emission from a higher-dimensional black hole
We discuss the graviton absorption probability (greybody factor) and the
cross-section of a higher-dimensional Schwarzschild black hole (BH). We are
motivated by the suggestion that a great many BHs may be produced at the LHC
and bearing this fact in mind, for simplicity, we shall investigate the
intermediate energy regime for a static Schwarzschild BH. That is, for
, where is the mass of the black hole and
is the energy of the emitted gravitons in -dimensions. To find
easily tractable solutions we work in the limit , where is the
angular momentum quantum number of the graviton.Comment: 10 pages, 8 figures, references added, typos corrected. Graviton
degeneracy factor included; main results remain unchange
Clinical utility of bone turnover markers in monitoring the withdrawal of treatment with oral bisphosphonates in postmenopausal osteoporosis
Summary
Bone markers may be useful to monitor response to treatment withdrawal in osteoporosis. We used two criteria for investigating the change in BTMs after withdrawal of bisphosphonate treatment. A larger increase in BTMs was associated with greater bone loss. Bone markers may be useful in monitoring of patients taking a pause from treatment.
Introduction
Measurement of bone turnover markers (BTMs) may be useful to monitor offset of treatment with bisphosphonates (BP) in osteoporosis. We assessed the effect of withdrawal of BP treatment by comparing the changes in BTMs and total hip (TH) bone density (BMD).
Methods
We studied postmenopausal osteoporotic women who had completed a randomised study of three oral BPs. After 2 years of treatment, participants with BMD T-score > − 2.5 and in whom it was considered clinically appropriate to discontinue treatment, were invited to participate in a further 2-year observational study. Biochemical response was assessed using BTMs (CTX and PINP) with offset being defined by two criteria: (1) an increase greater than the least significant change (LSC) and (2) an increase above the reference mean value.
Results
Fifty women completed the study. At 48 weeks after stopping BPs, CTX was greater than the LSC for 66% of women and PINP 72%; CTX was above the reference mean for 64% of women and PINP 42%. The decrease in THBMD was greater for women with the largest increase in BTM compared to those with continued suppression (mean difference for CTX was − 2.98%, 95%CI − 4.75 to − 1.22, P < 0.001, PINP − 2.25%, 95% CI − 4.46 to − 0.032, P = 0.046).
Conclusion
The measurement of BTM after withdrawal of BPs is potentially useful to evaluate patients that are taking a pause from treatment. An increase in BTMs more than the LSC and/or reference mean reflects loss of treatment effect and identifies patients that are likely to have a decrease in BMD. Such changes could provide an indication for reintroduction of treatment
Multiwavelength Studies of Young OB Associations
We discuss how contemporary multiwavelength observations of young
OB-dominated clusters address long-standing astrophysical questions: Do
clusters form rapidly or slowly with an age spread? When do clusters expand and
disperse to constitute the field star population? Do rich clusters form by
amalgamation of smaller subclusters? What is the pattern and duration of
cluster formation in massive star forming regions (MSFRs)? Past observational
difficulties in obtaining good stellar censuses of MSFRs have been alleviated
in recent studies that combine X-ray and infrared surveys to obtain rich,
though still incomplete, censuses of young stars in MSFRs. We describe here one
of these efforts, the MYStIX project, that produced a catalog of 31,784
probable members of 20 MSFRs. We find that age spread within clusters are real
in the sense that the stars in the core formed after the cluster halo. Cluster
expansion is seen in the ensemble of (sub)clusters, and older dispersing
populations are found across MSFRs. Direct evidence for subcluster merging is
still unconvincing. Long-lived, asynchronous star formation is pervasive across
MSFRs.Comment: 22 pages, 9 figures. To appear in "The Origin of Stellar Clusters",
edited by Steven Stahler, Springer, 2017, in pres
Cost effectiveness of thrombolytic therapy with tissue plasminogen activator as compared with streptokinase for acute myocardial infarction
BACKGROUND. Patients with acute myocardial infarction who were treated with accelerated tissue plasminogen activator (t-PA) (given over a period of 1 1/2 hours rather than the conventional 3 hours, and with two thirds of the dose given in the first 30 minutes) had a 30-day mortality that was 15 percent lower than that of pati
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