768 research outputs found
The flight of the bumblebee: vacuum solutions of a gravity model with vector-induced spontaneous Lorentz symmetry breaking
We study the vacuum solutions of a gravity model where Lorentz symmetry is
spontaneously broken once a vector field acquires a vacuum expectation value.
Results are presented for the purely radial Lorentz symmetry breaking (LSB),
radial/temporal LSB and axial/temporal LSB. The purely radial LSB result
corresponds to new black hole solutions. When possible, Parametrized
Post-Newtonian (PPN) parameters are computed and observational boundaries used
to constrain the Lorentz symmetry breaking scale.Comment: 12 pages, 2 figure
The spherical probe electric field and wave experiment
The experiment is designed to measure the electric field and density fluctuations with sampling rates up to 40,000 samples/sec. The description includes Langmuir sweeps that can be made to determine the electron density and temperature, the study of nonlinear processes that result in acceleration of plasma, and the analysis of large scale phenomena where all four spacecraft are needed
Management of emerging multidrug-resistant tuberculosis in a low-prevalence setting
AbstractMultidrug-resistant (MDR) tuberculosis (TB) is an emerging concern in communities with a low TB prevalence and a high standard of public health. Twenty-three consecutive adult MDR TB patients who were treated at our institution between 2007 and 2013 were reviewed for demographic characteristics and anti-TB treatment management, which included surgical procedures and long-term patient follow-up. This report of our experience emphasizes the need for an individualized approach as MDR TB brings mycobacterial disease management to a higher level of expertise, and for a balance to be found between international current guidelines and patient-tailored treatment strategies
Active spacecraft potential control for Cluster ? implementation and first results
International audienceElectrostatic charging of a spacecraft modifies the distribution of electrons and ions before the particles enter the sensors mounted on the spacecraft body. The floating potential of magnetospheric satellites in sunlight very often reaches several tens of volts, making measurements of the cold (several eV) component of the ambient ions impossible. The plasma electron data become contaminated by large fluxes of photoelectrons attracted back into the sensors. The Cluster spacecraft are equipped with emitters of the liquid metal ion source type, producing indium ions at 5 to 9 keV energy at currents of some tens of microampere. This current shifts the equilibrium potential of the spacecraft to moderately positive values. The design and principles of the operation of the instrument for active spacecraft potential control (ASPOC) are presented in detail. Experience with spacecraft potential control from the commissioning phase and the first two months of the operational phase are now available. The instrument is operated with constant ion current for most of the time, but tests have been carried out with varying currents and a "feedback" mode with the instrument EFW, which measures the spacecraft potential . That has been reduced to values according to expectations. In addition, the low energy electron measurements show substantially reduced fluxes of photoelectrons as expected. The flux decrease in photoelectrons returning to the spacecraft, however, occurs at the expense of an enlarged sheath around the spacecraft which causes problems for boom-mounted probes
First results of electric field and density observations by Cluster EFW based on initial months of operation
International audienceHighlights are presented from studies of the electric field data from various regions along the Cluster orbit. They all point towards a very high coherence for phenomena recorded on four spacecraft that are separated by a few hundred kilometers for structures over the whole range of apparent frequencies from 1 mHz to 9 kHz. This presents completely new opportunities to study spatial-temporal plasma phenomena from the magnetosphere out to the solar wind. A new probe environment was constructed for the CLUSTER electric field experiment that now produces data of unprecedented quality. Determination of plasma flow in the solar wind is an example of the capability of the instrument
Comparisons between MHD model calculations and observations of Cassini flybys of Titan
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94689/1/jgra18227.pd
Active tuberculosis, sequelae and COVID-19 co-infection: first cohort of 49 cases.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) pandemic has attracted interest because of its global rapid spread, clinical severity, high mortality rate, and capacity to overwhelm healthcare systems [1, 2]. SARS-CoV-2 transmission occurs mainly through droplets, although surface contamination contributes and debate continues on aerosol transmission [3\u20135]
Role of eHealth application Oncokompas in supporting self-management of symptoms and health-related quality of life in cancer survivors:a randomised, controlled trial
Background Knowledge about the efficacy of behavioural intervention technologies that can be used by cancer survivors independently from a health-care provider is scarce. We aimed to assess the efficacy, reach, and usage of Oncokompas, a web-based eHealth application that supports survivors in self-management by monitoring health-related quality of life (HRQOL) and cancer-generic and tumour-specific symptoms and obtaining tailored feedback with a personalised overview of supportive care options. Methods In this non-blinded, randomised, controlled trial, we recruited patients treated at 14 hospitals in the Netherlands for head and neck cancer, colorectal cancer, breast cancer, Hodgkin lymphoma, or non-Hodgkin lymphoma. Adult survivors (aged ≥18 years) were recruited through the Netherlands Cancer Registry (NCR) and invited by their treating physician through the Patient Reported Outcomes Following Initial Treatment and Long term Evaluation of Survivorship (PROFILES) registry. Participants were randomly assigned (1:1) by an independent researcher to the intervention group (access to Oncokompas) or control group (access to Oncokompas after 6 months), by use of block randomisation (block length of 68), stratified by tumour type. The primary outcome was patient activation (knowledge, skills, and confidence for self-management), assessed at baseline, post-intervention, and 3-month and 6-month follow-up. Linear mixed models (intention-to-treat) were used to assess group differences over time from baseline to 6-month follow-up. The trial is registered in the Netherlands Trial Register, NTR5774 and is completed. Findings Between Oct 12, 2016, and May 24, 2018, 625 (21%) of 2953 survivors assessed for eligibility were recruited and randomly assigned to the intervention (320) or control group (305). Median follow-up was 6 months (IQR 6−6). Patient activation was not significantly different between intervention and control group over time (difference at 6-month follow-up 1·7 [95% CI −0·8–4·1], p=0·41). Interpretation Oncokompas did not improve the amount of knowledge, skills, and confidence for self-management in cancer survivors. This study contributes to the evidence for the development of tailored strategies for development and implementation of behavioural intervention technologies among cancer survivors
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