96 research outputs found
Spinning charged BTZ black holes and self-dual particle-like solutions
We generate from the static charged BTZ black hole a family of spinning
charged solutions to the Einstein-Maxwell equations in 2+1 dimensions. These
solutions go over, in a suitable limit, to self-dual spinning charged
solutions, which are horizonless and regular, with logarithmically divergent
mass and spin. To cure this divergence, we add a topological Chern-Simons term
to the gauge field action. The resulting self-dual solution is horizonless,
regular, and asymptotic to the extreme BTZ black hole.Comment: 10 pages, LaTex, no figure
Mixing-Induced CP Violation in the Decay within the Standard Model
Recently, flavour symmetry of strong interactions has been combined
with certain dynamical assumptions to derive triangle relations among -meson
decay-amplitudes. We show that these relations allow a prediction of the
mixing-induced CP asymmetry \acpmi(B_d\to K^0\bar K^0). Contrary to
statements made in several previous papers, this asymmetry should be
non-vanishing in the Standard Model due to QCD-penguins with internal up- and
charm-quark exchanges and could be as large as \order(30\%). The branching
ratio BR is expected to be of \order(10^{-6}). In the
future, the results presented in this letter should allow interesting tests of
the triangle relations and of the Standard Model description of CP
violation.Comment: 13 pages (LaTeX) + 4 figures included, Munich Technical University
preprint TUM-T31-76/9
Design and testing of a lobed mixer for the study of mixing enhancement in reacting flows
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.Includes bibliographical references (p. 81-84).by Thomas G. London.M.S
Effect of the Space-like Penguin Diagrams on CP Asymmetries in Exclusive B Decays
The space-like penguin contributions were ignored on little ground in many
previous studies of nonleptonic B decays and CP violation. Taking the
penguin-dominated channels and
for example, we illustrate the
non-negligible effects of the space-like penguin diagrams on CP asymmetries.
Some quali- tative remarks are given on the gluonic penguin picture and the
direct CP violation in exclusive two-body decays of B mesons.Comment: 10 Latex pages, 2 figures. (Accepted for publication in Physics
Letters B
Cardiac and arterial interactions in end-stage renal disease
Cardiac and arterial interactions in end-stage renal disease. Although cardiac hypertrophy is a frequent complication of end-stage renal disease (ESRD), relatively little is known about large arterial geometry and function in vivo in these patients, and the relationship between arterial changes and cardiac hypertrophy is unknown. Common carotid artery (CCA) intima-media thickness and internal diameter and left ventricular geometry and function were determined by ultrasound imaging in 70 uncomplicated ESRD patients and in 50 age-, sex-, and blood pressure-matched controls. Arterial distensibility and compliance were determined from simultaneously recorded CCA diameter and stroke changes in diameter and CCA pressure waveforms, obtained by applanation tonometry, and also by the measurement of carotid-femoral pulse wave velocity. Compared with control subjects, ESRD patients had greater left ventricular diameter (P < 0.01), wall thicknesses and mass (P < 0.001), increased CCA diameter (6.25 ± 0.87 vs. 5.55 ± 0.65 mm; P < 0.001), larger CCA intima-media thickness (777 ± 115 vs. 678 ± 105 ” m; P < 0.001) and intima-media cross-sectional area (17.5 ± 4.5 vs. 13.4 ± 3.3mm2; P < 0.001). In uremic patients, arterial hypertrophy was associated with decreased CCA distensibility (17.8 ± 8.8 vs. 24.0 ± 12.7kPaâ1 · 10â3; P < 0.001) and compliance (5.15 ± 2 vs. 6.0 ± 2.5m2 · kPaâ1 · 10â7; P < 0.05), accelerated carotid-femoral pulse wave velocity (1055 ± 290 vs. 957 ± 180 cm/seconds; P < 0.001), early return and increased effect of arterial wave reflections (20.5 ± 15.4 vs. 9.2 ± 18.4%; P < 0.001). The latter phenomenons were responsible for increased pulsatile pressure load in CCA (58.3 ± 21 vs. 48 ± 17mm Hg; P < 0.01) and were associated with a decreased subendocardial viability index (157 ± 31 vs. 173 ± 30%; P < 0.001). The CCA diameter was correlated with the left ventricular diameter (P < 0.01), and a significant correlations existed between CCA wall thickness or CCA intima-media cross-sectional area and left ventricular wall thicknesses and/or left ventricular mass (P < 0.01). In multivariate analysis, these relationships were independent regarding age, sex, blood pressure and body surface area. The present study documents parallel cardiac and vascular adaptation in ESRD, and demonstrates the potential contribution of structural and functional large artery alterations to the pathogenesis of left ventricular hypertrophy and functional alterations
Low parathyroid hormone status induced by high dialysate calcium is an independent risk factor for cardiovascular death in hemodialysis patients
Here we studied a possible association between low parathyroid hormone (PTH) status and mortality in incident patients undergoing hemodialysis . A total of 1983 patients were included at baseline and prospectively followed for 24 months. Patients were classified according to their Kidney Disease: Improving Global Outcomes PTH status at baseline and at 12 months, and mortality evaluated at 12 to 24 months using adjusted Cox analysis. Factors potentially involved in PTH status variability between baseline and 12 months were analyzed. A decrease in serum PTH from normal or high to low values between baseline and 12 months was associated with significantly increased cardiovascular mortality at 12 to 24 months (hazard ratio, 2.03; 95% confidence interval, 1.22â3.36). For patients with high or normal baseline PTH levels, the main independent factor at 6 months for a decrease to low PTH levels at 12 months was high dialysate calcium (1.75 mmol/L), whereas prescription of nonâcalcium-based phosphate binders was associated with a lower risk of PTH decrease. In the high cardiovascular (CV) mortality risk subgroup of patients who acquired a low PTH status at 12 months, the main independent factor at 12 months associated with significant 12- to 24-month CV mortality was high dialysate calcium (odds ratio, 5.44; 95% CI, 2.52â11.75). Thus, patients with a serum PTH decrease to low values after 1 year of hemodialysis treatment are at high risk of short-term CV death. High dialysate calcium was an important contributor to PTH oversuppression, and continued use was associated with increased CV mortality
Exploring New Physics in the System
Employing the SU(2) isospin symmetry of strong interactions and estimates
borrowed from effective field theory, we explore the impact of new physics on
the decays and in a model-independent
manner. To this end, we introduce - in addition to the usual mixing-induced CP
asymmetry in - a set of three observables, which may not only
provide smoking-gun signals for new-physics contributions to different isospin
channels, but also valuable insights into hadron dynamics. Imposing dynamical
hierarchies of amplitudes, we discuss various patterns of these observables,
including also scenarios with small and large rescattering processes. Whereas
the system provides, in general, a powerful tool to search for
indications of new physics, there is also an unfortunate case, where such
effects cannot be distinguished from those of the Standard Model.Comment: 14 pages, LaTeX, 2 figure
The future of European Nephrology 'Guidelines' - a declaration of intent by European Renal Best Practice (ERBP)
The disparities of medical practice, together with a growing number of possible interventions, have increased the demand for well-conceived guidance for practitioners [1]. However, this development is hampered by the number and quality of scientific studies that test medical hypotheses, which are often unsatisfactory. This is especially true in nephrology, where well-conducted controlled trials are rare [2]. Because patients with renal failure are generally excluded from controlled studies in the general population [3], the development of sufficiently well-founded guidance in nephrology has always been difficult.
With the development of European Best Practice Guidelines (EBPG), the European Renal AssociationâEuropean Dialysis and Transplantation Association (ERAâEDTA) has created its own guidance-generating process. Similar initiatives have also arisen in the USA (Kidney Disease Outcome InitiativeâK/DOQI), Australia (Caring for Australasians with Renal ImpairmentâCARI), Canada (Canadian Society of NephrologyâCSN), the UK (United Kingdom Renal AssociationâUKRA), as well as at several other locations around the world. These institutions have generated a plethora of often parallel recommendations on similar topics but sometimes with different messages [4].
The question can be asked: âIs there still a place for an institution generating European nephrology guidance?â If there is, how should such an initiative be managed to conform with current demands? To answer these questions, the Council of ERAâEDTA set up a commission that convened three times in the course of 2008â09.
The present text is a distillation of the discussions, reflections and final conclusions of this commission. It is an ad hoc document, reflecting the current status. In the future, concepts and attitudes might change, as medical thinking is influenced by changes in practice, needs, general philosophy, ethics and political/financial conditions
Gravitating Chern-Simons vortices
The construction of self-dual vortex solutions to the Chern-Simons-Higgs
model (with a suitable eighth-order potential) coupled to Einstein gravity in
(2 + 1) dimensions is reconsidered. We show that the self-duality condition may
be derived from the sole assumption . Next, we derive a family of
exact, doubly self-dual vortex solutions, which interpolate between the
symmetrical and asymmetrical vacua. The corresponding spacetimes have two
regions at spatial infinity. The eighth-order Higgs potential is positive
definite, and closed timelike curves are absent, if the gravitational constant
is chosen to be negative.Comment: 11 pages, LaTe
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