490 research outputs found
Dirac Equation with Spin Symmetry for the Modified P\"oschl-Teller Potential in -dimensions
We present solutions of the Dirac equation with spin symmetry for vector and
scalar modified P\"oschl-Teller potential within framework of an approximation
of the centrifugal term. The relativistic energy spectrum is obtained using the
Nikiforov-Uvarov method and the two-component spinor wavefunctions are obtain
are in terms of the Jacobi polynomials. It is found that there exist only
positive-energy states for bound states under spin symmetry, and the energy
levels increase with the dimension and the potential range parameter .Comment: 9 pages and 1tabl
The Weak Gravity Conjecture and the Viscosity Bound with Six-Derivative Corrections
The weak gravity conjecture and the shear viscosity to entropy density bound
place constraints on low energy effective field theories that may help to
distinguish which theories can be UV completed. Recently, there have been
suggestions of a possible correlation between the two constraints. In some
interesting cases, the behavior was precisely such that the conjectures were
mutually exclusive. Motivated by these works, we study the mass to charge and
shear viscosity to entropy density ratios for charged AdS5 black branes, which
are holographically dual to four-dimensional CFTs at finite temperature. We
study a family of four-derivative and six-derivative perturbative corrections
to these backgrounds. We identify the region in parameter space where the two
constraints are satisfied and in particular find that the inclusion of the
next-to-leading perturbative correction introduces wider possibilities for the
satisfaction of both constraints.Comment: 24 pages, 6 figures, v2: published version, refs added, minor
clarificatio
A randomized phase 3 study of ixazomibâdexamethasone versus physicianâs choice in relapsed or refractory AL amyloidosis
In the first phase 3 study in relapsed/refractory AL amyloidosis (TOURMALINE-AL1 NCT01659658), 168 patients with relapsed/refractory AL amyloidosis after 1â2 prior lines were randomized to ixazomib (4âmg, days 1, 8, 15) plus dexamethasone (20âmg, days 1, 8, 15, 22; nâ=â85) or physicianâs choice (dexamethasoneâ±âmelphalan, cyclophosphamide, thalidomide, or lenalidomide; nâ=â83) in 28-day cycles until progression or toxicity. Primary endpoints were hematologic response rate and 2-year vital organ deterioration or mortality rate. Only the first primary endpoint was formally tested at this interim analysis. Best hematologic response rate was 53% with ixazomibâdexamethasone vs 51% with physicianâs choice (pâ=â0.76). Complete response rate was 26 vs 18% (pâ=â0.22). Median time to vital organ deterioration or mortality was 34.8 vs 26.1 months (hazard ratio 0.53; 95% CI, 0.32â0.87; pâ=â0.01). Median treatment duration was 11.7 vs 5.0 months. Adverse events of clinical importance included diarrhea (34 vs 30%), rash (33 vs 20%), cardiac arrhythmias (26 vs 15%), nausea (24 vs 14%). Despite not meeting the first primary endpoint, all time-to-event data favored ixazomibâdexamethasone. These results are clinically relevant to this relapsed/refractory patient population with no approved treatment options
Extreme Energy Cosmic Rays: Bottom-up vs. Top-down scenarii
We present an overview on extreme energy cosmic rays (EECR) and the
fundamental physics connected with them. The top-down and bottom-up scenarii
are contrasted. We summarize the essential features underlying the top-down
scenarii for EECR, namely, the lifetime and the mass {\bf imposed} to the heavy
relics whatever they be: topological and non-topological solitons, X-particles,
cosmic defects, microscopic black-holes, fundamental strings. An unified
formula for the quantum decay rate of all these objects was provided in
hep-ph/0202249. The key point in the top-down scenarii is the necessity to {\bf
adjust} the lifetime of the heavy object to the age of the universe. The
natural lifetimes of such heavy objects are, however, microscopic times
associated to the GUT energy scale (sim 10^{-28} sec. or shorter); such heavy
objects could have been abundantly formed by the end of inflation and it seems
natural they decayed shortly after being formed. The arguments produced to {\bf
fine tune} the relics lifetime to the age of the universe are critically
analyzed. The annihilation scenario (`Wimpzillas') is analyzed too. Top-down
scenarii based on networks of topological defects are strongly disfavored at
the light of the recent CMB anisotropy observations. We discuss the
acceleration mechanisms of cosmic rays,their possible astrophysical sources and
the main open physical problems and difficulties in the context of bottom-up
scenarii, and we conclude by outlining the expectations from future
observatories like EUSO and where the theoretical effort should be placed.Comment: LaTex, 16 pages, 2 .eps figures. The annihilation scenario
(Wimpzillas) is included and the discussion on gamma ray bursts improved.
Based on lectures at the Fourth International Workshop on `New Worlds in
Astroparticle Physics' in Faro, Portugal, September 2002, at the 9th Course
on Astrofundamental Physics of the Chalonge School, Palermo, Italia,
September 2002 and at the SOWG EUSO meeting, Roma, Italia, November 200
Quasi-normal frequencies: Key analytic results
The study of exact quasi-normal modes [QNMs], and their associated
quasi-normal frequencies [QNFs], has had a long and convoluted history -
replete with many rediscoveries of previously known results. In this article we
shall collect and survey a number of known analytic results, and develop
several new analytic results - specifically we shall provide several new QNF
results and estimates, in a form amenable for comparison with the extant
literature. Apart from their intrinsic interest, these exact and approximate
results serve as a backdrop and a consistency check on ongoing efforts to find
general model-independent estimates for QNFs, and general model-independent
bounds on transmission probabilities. Our calculations also provide yet another
physics application of the Lambert W function. These ideas have relevance to
fields as diverse as black hole physics, (where they are related to the damped
oscillations of astrophysical black holes, to greybody factors for the Hawking
radiation, and to more speculative state-counting models for the Bekenstein
entropy), to quantum field theory (where they are related to Casimir energies
in unbounded systems), through to condensed matter physics, (where one may
literally be interested in an electron tunelling through a physical barrier).Comment: V1: 29 pages; V2: Reformatted, 31 pages. Title changed to reflect
major additions and revisions. Now describes exact QNFs for the double-delta
potential in terms of the Lambert W function. V3: Minor edits for clarity.
Four references added. No physics changes. Still 31 page
Birtamimab plus standard of care in light-chain amyloidosis: the phase 3 randomized placebo-controlled VITAL trial
Amyloid light-chain (AL) amyloidosis is a rare, typically fatal disease characterized by the accumulation of misfolded immunoglobulin light chains (LCs). Birtamimab is an investigational humanized monoclonal antibody designed to neutralize toxic LC aggregates and deplete insoluble organ-deposited amyloid via macrophage-induced phagocytosis. VITAL was a phase 3 randomized, double-blind, placebo-controlled clinical trial assessing the efficacy and safety of birtamimab + standard of care (SOC) in 260 newly diagnosed, treatment-naive patients with AL amyloidosis. Patients received 24 mg/kg IV birtamimab + SOC or placebo + SOC every 28 days. The primary composite end point was the time to all-cause mortality (ACM) or centrally adjudicated cardiac hospitalization â„91 days after the first study drug infusion. The trial was terminated early after an interim futility analysis; there was no significant difference in the primary composite end point (hazard ratio [HR], 0.826; 95% confidence interval [CI], 0.574-1.189; log-rank P = .303). A post hoc analysis of patients with Mayo stage IV AL amyloidosis, those at the highest risk of early mortality, showed significant improvement in the time to ACM with birtamimab at month 9 (HR, 0.413; 95% CI, 0.191-0.895; log-rank P = .021). At month 9, 74% of patients with Mayo stage IV AL amyloidosis treated with birtamimab and 49% of those given placebo survived. Overall, the rates of treatment-emergent adverse events (TEAEs) and serious TEAEs were generally similar between treatment arms. A confirmatory phase 3 randomized, double-blind, placebo-controlled clinical trial of birtamimab in patients with Mayo stage IV AL amyloidosis (AFFIRM-AL; NCT04973137) is currently enrolling. The VITAL trial was registered at www.clinicaltrials.gov as #NCT02312206
Symmetric informationally complete positive operator valued measure and probability representation of quantum mechanics
Symmetric informationally complete positive operator valued measures
(SIC-POVMs) are studied within the framework of the probability representation
of quantum mechanics. A SIC-POVM is shown to be a special case of the
probability representation. The problem of SIC-POVM existence is formulated in
terms of symbols of operators associated with a star-product quantization
scheme. We show that SIC-POVMs (if they do exist) must obey general rules of
the star product, and, starting from this fact, we derive new relations on
SIC-projectors. The case of qubits is considered in detail, in particular, the
relation between the SIC probability representation and other probability
representations is established, the connection with mutually unbiased bases is
discussed, and comments to the Lie algebraic structure of SIC-POVMs are
presented.Comment: 22 pages, 1 figure, LaTeX, partially presented at the Workshop
"Nonlinearity and Coherence in Classical and Quantum Systems" held at the
University "Federico II" in Naples, Italy on December 4, 2009 in honor of
Prof. Margarita A. Man'ko in connection with her 70th birthday, minor
misprints are corrected in the second versio
Further investigation of confirmed urinary tract infection (UTI) in children under five years: a systematic review.
Background: Further investigation of confirmed UTI in children aims to prevent renal scarring and future complications. Methods: We conducted a systematic review to determine the most effective approach to the further investigation of confirmed urinary tract infection (UTI) in children under five years of age. Results: 73 studies were included. Many studies had methodological limitations or were poorly reported. Effectiveness of further investigations: One study found that routine imaging did not lead to a reduction in recurrent UTIs or renal scarring. Diagnostic accuracy: The studies do not support the use of less invasive tests such as ultrasound as an alternative to renal scintigraphy, either to rule out infection of the upper urinary tract (LR- = 0.57, 95%CI: 0.47, 0.68) and thus to exclude patients from further investigation or to detect renal scarring (LR+ = 3.5, 95% CI: 2.5, 4.8). None of the tests investigated can accurately predict the development of renal scarring. The available evidence supports the consideration of contrast-enhanced ultrasound techniques for detecting vesico-ureteric reflux (VUR), as an alternative to micturating cystourethrography (MCUG) (LR+ = 14.1, 95% CI: 9.5, 20.8; LR- = 0.20, 95%CI: 0.13, 0.29); these techniques have the advantage of not requiring exposure to ionising radiation. Conclusion: There is no evidence to support the clinical effectiveness of routine investigation of children with confirmed UTI. Primary research on the effectiveness, in terms of improved patient outcome, of testing at all stages in the investigation of confirmed urinary tract infection is urgently required
Disorder Effects on Exciton-Polariton Condensates
The impact of a random disorder potential on the dynamical properties of Bose
Einstein condensates is a very wide research field. In microcavities, these
studies are even more crucial than in the condensates of cold atoms, since
random disorder is naturally present in the semiconductor structures. In this
chapter, we consider a stable condensate, defined by a chemical potential,
propagating in a random disorder potential, like a liquid flowing through a
capillary. We analyze the interplay between the kinetic energy, the
localization energy, and the interaction between particles in 1D and 2D
polariton condensates. The finite life time of polaritons is taken into account
as well. In the first part, we remind the results of [G. Malpuech et al. Phys.
Rev. Lett. 98, 206402 (2007).] where we considered the case of a static
condensate. In that case, the condensate forms either a glassy insulating phase
at low polariton density (strong localization), or a superfluid phase above the
percolation threshold. We also show the calculation of the first order spatial
coherence of the condensate versus the condensate density. In the second part,
we consider the case of a propagating non-interacting condensate which is
always localized because of Anderson localization. The localization length is
calculated in the Born approximation. The impact of the finite polariton life
time is taken into account as well. In the last section we consider the case of
a propagating interacting condensate where the three regimes of strong
localization, Anderson localization, and superfluid behavior are accessible.
The localization length is calculated versus the system parameters. The
localization length is strongly modified with respect to the non-interacting
case. It is infinite in the superfluid regime whereas it is strongly reduced if
the fluid flows with a supersonic velocity.Comment: chapter for a book "Exciton Polaritons in Microcavities: New
Frontiers" by Springer (2012), the original publication is available at
http://www.springerlink.co
The Association of State Opioid Misuse Prevention Policies With Patientâ and ProviderâRelated Outcomes: A Scoping Review
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154648/1/milq12436.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154648/2/milq12436_am.pd
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