1,685 research outputs found
Scalar Field Cosmologies With Inverted Potentials
Regular bouncing solutions in the framework of a scalar-tensor gravity model
were found in a recent work. We reconsider the problem in the Einstein frame
(EF) in the present work. Singularities arising at the limit of physical
viability of the model in the Jordan frame (JF) are either of the Big Bang or
of the Big Crunch type in the EF. As a result we obtain integrable scalar field
cosmological models in general relativity (GR) with inverted double-well
potentials unbounded from below which possess solutions regular in the future,
tending to a de Sitter space, and starting with a Big Bang. The existence of
the two fixed points for the field dynamics at late times found earlier in the
JF becomes transparent in the EF.Comment: 18 pages, 4 figure
Bouncing Universes in Scalar-Tensor Gravity Models admitting Negative Potentials
We consider the possibility to produce a bouncing universe in the framework
of scalar-tensor gravity models in which the scalar field potential may be
negative, and even unbounded from below. We find a set of viable solutions with
nonzero measure in the space of initial conditions passing a bounce, even in
the presence of a radiation component, and approaching a constant gravitational
coupling afterwards. Hence we have a model with a minimal modification of
gravity in order to produce a bounce in the early universe with gravity tending
dynamically to general relativity (GR) after the bounce.Comment: 12 pages, Improved presentation with 4 figures, Results and
conclusions unchange
Some exact solutions with torsion in 5-D Einstein-Gauss-Bonnet gravity
Exact solutions with torsion in Einstein-Gauss-Bonnet gravity are derived.
These solutions have a cross product structure of two constant curvature
manifolds. The equations of motion give a relation for the coupling constants
of the theory in order to have solutions with nontrivial torsion. This relation
is not the Chern-Simons combination. One of the solutions has a structure and is so the purely gravitational analogue of the
Bertotti-Robinson space-time where the torsion can be seen as the dual of the
covariantly constant electromagnetic field.Comment: 19 pages, LaTex, no figures. References added, notation clarified.
Accepted for publication on Physical Review
Effectiveness of delayed-release dimethyl fumarate on patient-reported outcomes and clinical measures in patients with relapsing-remitting multiple sclerosis in a real-world clinical setting: PROTEC.
Ensaio clÃnico PROTEC, Protocolo nº 109MS408Abstract
BACKGROUND:
Patient-reported outcomes (PRO) and clinical outcomes give a broad assessment of relapsing-remitting multiple sclerosis (RRMS) disease.
OBJECTIVE:
The aim is to evaluate the effectiveness of delayed-release dimethyl fumarate (DMF) on disease activity and PROs in patients with RRMS in the clinic.
METHODS:
PROTEC, a phase 4, open-label, 12-month observational study, assessed annualized relapse rate (ARR), proportion of patients relapsed, and changes in PROs. Newly diagnosed and early MS (≤3.5 EDSS and ≤1 relapse in the prior year) patient subgroups were evaluated.
RESULTS:
Unadjusted ARR at 12 months post-DMF versus 12 months before DMF initiation was 75% lower (0.161 vs. 0.643, p < 0.0001) overall (n = 1105) and 84%, 77%, and 71% lower in newly diagnosed, ≤3.5 EDSS, and ≤1 relapse subgroups, respectively. Overall, 88% of patients were relapse-free 12 months after DMF initiation (84%, newly diagnosed; 88%, ≤3.5 EDSS; 88%, ≤1 relapse). PRO measures for fatigue, treatment satisfaction, daily living, and work improved significantly over 12 months of DMF versus baseline.
CONCLUSION:
At 12 months after versus 12 months before DMF initiation, ARR was significantly lower, the majority of patients were relapse-free, and multiple PRO measures showed improvement (overall and for subgroups), suggesting that DMF is effective based on clinical outcomes and from a patient perspective.Clinical trial: A Study Evaluating the Effectiveness of Tecfidera (Dimethyl Fumarate) on Multiple Sclerosis (MS) Disease Activity and Patient-Reported Outcomes (PROTEC), NCT01930708,info:eu-repo/semantics/publishedVersio
A SOA-Based Platform to Support Clinical Data Sharing
The eSource Data Interchange Group, part of the Clinical Data Interchange Standards Consortium, proposed five scenarios to guide stakeholders in the development of solutions for the capture of eSource data. The fifth scenario was subdivided into four tiers to adapt the functionality of electronic health records to support clinical research. In order to develop a system belonging to the \u201cInteroperable\u201d Tier, the authors decided to adopt the service-oriented architecture paradigm to support technical interoperability, Health Level Seven Version 3 messages combined with LOINC (Logical Observation Identifiers Names and Codes) vocabulary to ensure semantic interoperability, and Healthcare Services Specification Project standards to provide process interoperability. The developed architecture enhances the integration between patient-care practice and medical research, allowing clinical data sharing between two hospital information systems and four clinical data management systems/clinical registries. The core is formed by a set of standardized cloud services connected through standardized interfaces, involving client applications. The system was approved by a medical staff, since it reduces the workload for the management of clinical trials. Although this architecture can realize the \u201cInteroperable\u201d Tier, the current solution actually covers the \u201cConnected\u201d Tier, due to local hospital policy restrictions
Individuazione e caratterizzazione di proteine coinvolte nella regolazione trascrizionale delle risposte alla solfo-carenza e a cadmio delle piante
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On the number of limit cycles of the Lienard equation
In this paper, we study a Lienard system of the form dot{x}=y-F(x),
dot{y}=-x, where F(x) is an odd polynomial. We introduce a method that gives a
sequence of algebraic approximations to the equation of each limit cycle of the
system. This sequence seems to converge to the exact equation of each limit
cycle. We obtain also a sequence of polynomials R_n(x) whose roots of odd
multiplicity are related to the number and location of the limit cycles of the
system.Comment: 10 pages, 5 figures. Submitted to Physical Review
Some results on homoclinic and heteroclinic connections in planar systems
Consider a family of planar systems depending on two parameters and
having at most one limit cycle. Assume that the limit cycle disappears at some
homoclinic (or heteroclinic) connection when We present a method
that allows to obtain a sequence of explicit algebraic lower and upper bounds
for the bifurcation set The method is applied to two quadratic
families, one of them is the well-known Bogdanov-Takens system. One of the
results that we obtain for this system is the bifurcation curve for small
values of , given by . We obtain
the new three terms from purely algebraic calculations, without evaluating
Melnikov functions
SLC transporters as therapeutic targets: Emerging opportunities
Solute carrier (SLC) transporters-a family of more than 300 membrane-bound proteins that facilitate the transport of a wide array of substrates across biological membranes-have important roles in physiological processes ranging from the cellular uptake of nutrients to the absorption of drugs and other xenobiotics. Several classes of marketed drugs target well-known SLC transporters, such as neurotransmitter transporters, and human genetic studies have provided powerful insight into the roles of more-recently characterized SLC transporters in both rare and common diseases, indicating a wealth of new therapeutic opportunities. This Review summarizes knowledge on the roles of SLC transporters in human disease, describes strategies to target such transporters, and highlights current and investigational drugs that modulate SLC transporters, as well as promising drug targets
Model Comparisons In Unstable Environments
The goal of this article is to develop formal tests to evaluate the relative in-sample performance of two competing, misspecified, nonnested models in the presence of possible data instability. Compared to previous approaches to model selection, which are based on measures of global performance, we focus on the local relative performance of the models. We propose tests that are based on different measures of local performance and that correspond to different null and alternative hypotheses. The empirical application provides insights into the time variation in the performance of a representative Euro-area Dynamic Stochastic General Equilibrium model relative to that of VARs
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