2,923 research outputs found
The Novel Control Loops of the Pulsed Power Converters for the CERN SPS Machine
The topic of this paper is the studies that were made in the framework of the renovation project of the CERN SPS accelerator's power converters. This project was initiated because these converters were designed 20 years ago and they will need to work another 20 years, due to the use of the SPS machine as the LHC injector
Ternary cluster decay within the liquid drop model
Longitudinal ternary and binary fission barriers of Ar, Ni and
Cf nuclei have been determined within a rotational liquid drop model
taking into account the nuclear proximity energy. For the light nuclei the
heights of the ternary fission barriers become competitive with the binary ones
at high angular momenta since the maximum lies at an outer position and has a
much higher moment of inertia.Comment: Talk presented at the 9th International Conference on Clustering
Aspects of Nuclear Structure and Dynamics (CLUSTERS'07
Rotational velocities of A-type stars II. Measurement of vsini in the northern hemisphere
This work is the second part of the set of measurements of vsini for A-type
stars, begun by Royer et al. (2002). Spectra of 249 B8 to F2-type stars
brighter than V=7 have been collected at Observatoire de Haute-Provence (OHP).
Fourier transforms of several line profiles in the range 4200--4600 A are used
to derive vsini from the frequency of the first zero. Statistical analysis of
the sample indicates that measurement error mainly depends on vsini and this
relative error of the rotational velocity is found to be about 5% on average.
The systematic shift with respect to standard values from Slettebak et al.
(1975), previously found in the first paper, is here confirmed. Comparisons
with data from the literature agree with our findings: vsini values from
Slettebak et al. are underestimated and the relation between both scales
follows a linear law: vsini(new) = 1.03 vsini(old) + 7.7. Finally, these data
are combined with those from the previous paper (Royer et al. 2002), together
with the catalogue of Abt & Morrell (1995). The resulting sample includes some
2150 stars with homogenized rotational velocities.Comment: 16 pages, includes 13 figures, accepted in A&
Stress fractures in 2011: practical approach
Stress fractures occur when excessive loads are applied to a bone whose mechanical strength is normal. Bone insufficiency fractures, in contrast, are due to physiological loads applied to bone of inadequate mechanical strength [1]. This contradistinction is obviously an oversimplifi cation. In practice, a continuum exists between these two clearly defined situations.
The objective of the third ODISSEE meetings [2,3] held under the aegis of the GRIO was to review current knowledge on stress fractures. The pathophysiology of stress fractures is still poorly understood. When loads are applied to a bone, particularly in a repetitive manner, an elastic deformity occurs, followed by a plastic deformity and, finally, by microfractures. Bone strength varies across individuals. It depends not only on the intrinsic qualities of the bone tissue, but also on the magnitude and repetitiveness of the loads applied to the bone. Bone tissue fatigue is an inability to repair the microdamage caused by mechanical loading. The number and length of the microfractures increase, resulting in a fracture with clinical symptoms and radiographic changes [4]. Stress fractures are a common reason for physician visits among athletes and military recruits. They account for 5% to 14% of all physician visits, depending on the study population [5,6].
Although stress fractures can arise at any site, the most common locations are the tibia, particularly in runners; the metatarsals (most notably the second and third metatarsals) in hikers, runners, dancers, and military recruits; the iliopubic and ischiopubic rami of the pelvis in military recruits, gymnasts, dancers, and soccer players; and the femur in cross-country runners. The calcaneus is also a common site of involvement in all populations. Stress fractures are rare at the upper limbs, except in high- level gymnasts country runners. The calcaneus is also a common site of involvement in all populations. Stress fractures are rare at the upper limbs,except in high-level gymnasts
HypercalcĂ©mie majeure rĂ©vĂ©latrice dâune sarcoĂŻdose induite par Ă©tanercept
Introduction
The principal secondary effects of anti-TNF alpha therapy are now well understood, particularly the risk of opportunistic infections. Other paradoxical effects have been described much more occasionally such as the developement of sarcoid-like granulomatous reactions.
Case report
We report here the case of a woman of 39 years treated for severe rheumatoid arthritis for five years with etanercept. She was admitted to hospital as an emergency with vomiting and diffuse abdominal pain. Investigations revealed severe hypercalcaemia and acute renal failure. After correction of the metabolic disturbances with rehydration and biphosphonates, CT scanning of the abdomen, pelvis and thorax showed bilateral interstitial infiltration and splenomegaly. The diagnosis of sarcoidosis was confirmed by endoscopic bronchial biopsies. Progress was satisfactory following withdrawal of the etanercept and corticosteroid therapy in reducing dosage.
Conclusion
The risk of induced sarcoidosis should be understood in patients receiving anti-TNF therapy and should be considered in cases of hypercalcaemia and/or splenomegaly
Is androgen therapy indicated in men with osteoporosis?
Male osteoporosis is not rare, and its management is a public health issue. The clinical evaluation must include investigations for one or more etiological factors such as hypogonadism, which is found in 5% to 15% of men with osteoporosis. Gradual development of moderate hypogonadism is the most common situation, and the prevalence of hypogonadism increases with advancing age. The wealth of scientific data establishing a major role for sex hormones in growth, bone turnover, and the osteoporotic fracture risk is in striking contrast to the paucity of therapeutic trials. Androgen therapy did not consistently produce bone mass gains, and no data on potential anti-fracture effects are available. Androgen therapy was not associated with significant increases in mortality, prostate disorders, or cardiovascular events, but few data were obtained in patients older than 75 years. In practice, in a male patient with osteoporosis, a diagnosis of marked and persistent hypogonadism requires investigations for treatable causes. In patients younger than 75 years of age, androgen replacement therapy should be started, in collaboration with an endocrinologist. A history of fractures indicates a need for additional osteoporosis pharmacotherapy. The risk/benefit ratio of androgen therapy is unclear in men older than 75 years, in whom a reasonable option consists in combining fall-prevention measures, vitamin D supplementation, and a medication proven to decrease the risk of proximal femoral fractures
Monoclonal gammopathy of undetermined significance, multiple myeloma, and osteoporosis
The finding of monoclonal gammopathy of undetermined significance (MGUS) is not infrequent during an evaluation for osteoporosis or a fracture. In most cases, the diagnosis is MGUS, whose prevalence increases with age. Although the impact of MGUS on bone mineral density, bone remodeling, and the fracture risk remains unclear, this asymptomatic hematological disorder may constitute a risk factor for osteoporosis. Furthermore, each year, 1% of patients with MGUS progress to multiple myeloma, a disease whose pathophysiology and association with bone loss and pathological fractures are increasingly well understood. Osteoporotic fractures, although probably common in myeloma patients, are less likely to be recognized. Here, we discuss the pathophysiology of myeloma and MGUS and their impact in terms of bone mineral density, osteoporotic fractures, and bone turnover markers
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