453 research outputs found
Existence of initial data satisfying the constraints for the spherically symmetric Einstein-Vlasov-Maxwell system
Using ODE techniques we prove the existence of large classes of initial data
satisfying the constraints for the spherically symmetric
Einstein-Vlasov-Maxwell system. These include data for which the ratio of total
charge to total mass is arbitrarily large.Comment: 12 page
Global existence of solutions for the relativistic Boltzmann equation with arbitrarily large initial data on a Bianchi type I space-time
We prove, for the relativistic Boltzmann equation on a Bianchi type I
space-time, a global existence and uniqueness theorem, for arbitrarily large
initial data.Comment: 17 page
Identifying and Indexing Icosahedral Quasicrystals from Powder Diffraction Patterns
We present a scheme to identify quasicrystals based on powder diffraction
data and to provide a standardized indexing. We apply our scheme to a large
catalog of powder diffraction patterns, including natural minerals, to look for
new quasicrystals. Based on our tests, we have found promising candidates
worthy of further exploration.Comment: 4 pages, 1 figur
Vortex-unbinding and finite-size effects in Tl2Ba2CaCu2O8 thin films
Current-voltage (-) characteristics of TlBaCaCuO thin
films in zero magnetic field are measured and analyzed with the conventional
Kosterlitz-Thouless-Berezinskii (KTB) approach, dynamic scaling approach and
finite-size scaling approach, respectively. It is found from these results that
the - relation is determined by the vortex-unbinding mechanism with the
KTB dynamic critical exponent . On the other hand, the evidence of
finite-size effect is also found, which blurs the feature of a phase
transition.Comment: Typo corrected & reference adde
Anomalous Anticipatory Responses in Networked Random Data
Abstract. We examine an 8-year archive of synchronized, parallel time series of random data from a world spanning network of physical random event generators (REGs). The archive is a publicly accessible matrix of normally distributed 200-bit sums recorded at 1 Hz which extends from August 1998 to the present. The primary question is whether these data show non-random structure associated with major events such as natural or man-made disasters, terrible accidents, or grand celebrations. Secondarily, we examine the time course of apparently correlated responses. Statistical analyses of the data reveal consistent evidence that events which strongly affect people engender small but significant effects. These include suggestions of anticipatory responses in some cases, leading to a series of specialized analyses to assess possible non-random structure preceding precisely timed events. A focused examination of data collected around the time of earthquakes with Richter magnitude 6 and greater reveals non-random structure with a number of intriguing, potentially important features. Anomalous effects in the REG data are seen only when the corresponding earthquakes occur in populated areas. No structure is found if they occur in the oceans. We infer that an important contributor to the effect is the relevance of the earthquake to humans. Epoch averaging reveals evidence for changes in the data some hours prior to the main temblor, suggestive of reverse causation
The Einstein-Vlasov sytem/Kinetic theory
The main purpose of this article is to guide the reader to theorems on global
properties of solutions to the Einstein-Vlasov system. This system couples
Einstein's equations to a kinetic matter model. Kinetic theory has been an
important field of research during several decades where the main focus has
been on nonrelativistic- and special relativistic physics, e.g. to model the
dynamics of neutral gases, plasmas and Newtonian self-gravitating systems. In
1990 Rendall and Rein initiated a mathematical study of the Einstein-Vlasov
system. Since then many theorems on global properties of solutions to this
system have been established. The Vlasov equation describes matter
phenomenologically and it should be stressed that most of the theorems
presented in this article are not presently known for other such matter models
(e.g. fluid models). The first part of this paper gives an introduction to
kinetic theory in non-curved spacetimes and then the Einstein-Vlasov system is
introduced. We believe that a good understanding of kinetic theory in
non-curved spacetimes is fundamental in order to get a good comprehension of
kinetic theory in general relativity.Comment: 31 pages. This article has been submitted to Living Rev. Relativity
(http://www.livingreviews.org
The Cauchy Problem for the Einstein Equations
Various aspects of the Cauchy problem for the Einstein equations are
surveyed, with the emphasis on local solutions of the evolution equations.
Particular attention is payed to giving a clear explanation of conceptual
issues which arise in this context. The question of producing reduced systems
of equations which are hyperbolic is examined in detail and some new results on
that subject are presented. Relevant background from the theory of partial
differential equations is also explained at some lengthComment: 98 page
The role of credit ratings on capital structure and its speed of adjustment: an international study
Using an international dataset, we examine the role of issuers’ credit ratings in explaining corporate leverage and the speed with which firms adjust toward their optimal level of leverage. We find that, in countries with a more market-oriented financial system, the impact of credit ratings on firms’ capital structure is more significant and that firms with a poorer credit rating adjust more rapidly. Furthermore, our results show some striking differences in the speed of adjusting capital structure between firms rated as speculative and investment grade, with the former adjusting much more rapidly. As hypothesized, those differences are statistically significant only for firms based in a more market-oriented economy
Digital outcome captures longitudinal degradation of upper-limb function in non-ambulant patients affected by neuromuscular disorders
peer reviewedPrecise upper limb function quantification is challenging but essential to judge efficacy of treatments for patients living with neuromuscular disorders. Lack of robust motor function endpoints has limited the number of clinical programs in this population and thus the access to innovative medication. The need for improving current outcomes and exploring innovative approaches, like wearable devices or video-based home assessment is consensual in the community. For ambulant patients affected by Duchenne muscular dystrophy (DMD), the EMA has recently qualified the first digital outcome as a primary endpoint in clinical trials: the stride velocity 95th percentile (SV95C). In this article we explore the possibility of using a similar outcome by measuring the motor function of the upper limbs in a population of non-ambulant patients affected with DMD and spinal muscular atrophy (SMA). Data for patients living with DMD was recorded in a natural history study including non-ambulant patients (N=16, age=13 ± 3 [8-19]). Comparison will be provided with data collected on non-ambulant patients affected by SMA. In both cases, patients wear two magneto-inertial measurement units, one on their wrist and one on their wheelchair. The digital outcome of interest quantifies the gestures where the patients develop the maximum energy with their upper limb, during the monthly recording period. It is called the 99th percentile of the total effort (TE99C). We compare the TE99C to the Performance of Upper Limb (PUL) scale in DMD and to the Motor Function Measurement (MFM32) in SMA. We evaluated the decrease of respectively PUL and MFM32 in the DMD and SMA studies and compared it to the evolution of TE99C. We will present the correlation between TE99C and the reference outcomes, as well as the longitudinal evolution of the different endpoints, in order to determine if the TE99C can constitute a valuable candidate to assess upper-limb motor function in neuromuscular disorders
Hematopoietic stem cell transplantation in Europe 2014: More than 40 000 transplants annually
A record number of 40 829 hematopoietic stem cell transplantation (HSCT) in 36 469 patients (15 765 allogeneic (43%), 20 704 autologous (57%)) were reported by 656 centers in 47 countries to the 2014 survey. Trends include: continued growth in transplant activity, more so in Eastern European countries than in the west; a continued increase in the use of haploidentical family donors (by 25%) and slower growth for unrelated donor HSCT. The use of cord blood as a stem cell source has decreased again in 2014. Main indications for HSCT were leukemias: 11 853 (33%; 96% allogeneic); lymphoid neoplasias; 20 802 (57%; 11% allogeneic); solid tumors; 1458 (4%; 3% allogeneic) and non-malignant disorders; 2203 (6%; 88% allogeneic). Changes in transplant activity include more allogeneic HSCT for AML in CR1, myeloproliferative neoplasm (MPN) and aplastic anemia and decreasing use in CLL; and more autologous HSCT for plasma cell disorders and in particular for amyloidosis. In addition, data on numbers of teams doing alternative donor transplants, allogeneic after autologous HSCT, autologous cord blood transplants are presented
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