151 research outputs found
Three-dimensional analytical magnetohydrostatic equilibria of rigidly rotating magnetospheres in cylindrical geometry
We present three-dimensional solutions of the magnetohydrostatic equations in
the co-rotating frame of reference outside a magnetized rigidly rotating
cylinder. We make no symmetry assumption for the magnetic field, but to be able
to make analytical progress we neglect outflows and specify a particular form
for the current density. The magnetohydrostatic equations can then be reduced
to a single linear partial differential equation for a pseudo-potential ,
from which the magnetic field can be calculated by differentiation. The
equation for can be solved by standard methods. The solutions can also be
used to determine the plasma pressure, density and temperature as functions of
all three spatial coordinates. Despite the obvious limitations of this
approach, it can for example be used as a simple tool to create
three-dimensional models for the closed field line regions of rotating
magnetospheres without rotational symmetry.Comment: 13 pages, 2 figures, accepted for publication by Geophysical and
Astrophysical Fluid Dynamic
Gravitational waves from single neutron stars: an advanced detector era survey
With the doors beginning to swing open on the new gravitational wave
astronomy, this review provides an up-to-date survey of the most important
physical mechanisms that could lead to emission of potentially detectable
gravitational radiation from isolated and accreting neutron stars. In
particular we discuss the gravitational wave-driven instability and
asteroseismology formalism of the f- and r-modes, the different ways that a
neutron star could form and sustain a non-axisymmetric quadrupolar "mountain"
deformation, the excitation of oscillations during magnetar flares and the
possible gravitational wave signature of pulsar glitches. We focus on progress
made in the recent years in each topic, make a fresh assessment of the
gravitational wave detectability of each mechanism and, finally, highlight key
problems and desiderata for future work.Comment: 39 pages, 12 figures, 2 tables. Chapter of the book "Physics and
Astrophysics of Neutron Stars", NewCompStar COST Action 1304. Minor
corrections to match published versio
Climate Change and Childhood Respiratory Health: A Call to Action for Paediatricians
Climate change (CC) is one of the main contributors to health emergencies worldwide. CC appears to be closely interrelated with air pollution, as some pollutants like carbon dioxide (CO2), nitrogen oxides (NOx) and black carbon are naturally occurring greenhouse gases. Air pollution may enhance the allergenicity of some plants and, also, has an adverse effect on respiratory health. Children are a uniquely vulnerable group that suffers disproportionately from CC burden. The increasing global warming related to CC has a big impact on plants' lifecycles, with earlier and longer pollen seasons, as well as higher pollen production, putting children affected by asthma and allergic rhinitis at risk for exacerbations. Extreme weather events may play a role too, not only in the exacerbations of allergic respiratory diseases but, also, in favouring respiratory infections. Even though paediatricians are already seeing the impacts of CC on their patients, their knowledge about CC-related health outcomes with specific regards to children's respiratory health is incomplete. This advocates for paediatricians' increased awareness and a better understanding of the CC impact on children's respiratory health. Having a special responsibility for children, paediatricians should actively be involved in policies aimed to protect the next generation from CC-related adverse health effects. Hence, there is an urgent need for them to take action and successfully educate families about CC issues. This paper aims at reviewing the evidence of CC-related environmental factors such as temperature, humidity, rainfall and extreme events on respiratory allergic diseases and respiratory infections in children and proposing specific actionable items for paediatricians to deal with CC-related health issues in their clinical practice
Response of Benthic Foraminifera to organic matter quantity and quality and bioavailable concentrations of metals in Aveiro Lagoon (Portugal)
This work analyses the distribution of living benthic foraminiferal assemblages of surface sediments in different intertidal areas of Ria de Aveiro (Portugal), a polihaline and anthropized coastal lagoon. The relationships among foraminiferal assemblages in association with environmental parameters (temperature, salinity, Eh and pH), grain size, the quantity and quality of organic matter (enrichment in carbohydrates, proteins and lipids), pollution caused by metals, and mineralogical data are studied in an attempt to identify indicators of adaptability to environmental stress. In particular, concentrations of selected metals in the surficial sediment are investigated to assess environmental pollution levels that are further synthetically parameterised by the Pollution Load Index (PLI). The PLI variations allowed the identification of five main polluted areas. Concentrations of metals were also analysed in three extracted phases to evaluate their possible mobility, bioavailability and toxicity in the surficial sediment. Polluted sediment in the form of both organic matter and metals can be found in the most confined zones. Whereas enrichment in organic matter and related biopolymers causes an increase in foraminifera density, pollution by metals leads to a decline in foraminiferal abundance and diversity in those zones. The first situation may be justified by the existence of opportunistic species (with high reproduction rate) that can live in low oxic conditions. The second is explained by the sensitivity of some species to pressure caused by metals. The quality of the organic matter found in these places and the option of a different food source should also explain the tolerance of several species to pollution caused by metals, despite their low reproductive rate in the most polluted areas. In this study, species that are sensitive and tolerant to organic matter and metal enrichment are identified, as is the differential sensitivity/tolerance of some species to metals enrichment.CNPq [401803/2010-4]; [PEst-OE/CTE/UI4035/2014]info:eu-repo/semantics/publishedVersio
ROCK Inhibitor Is Not Required for Embryoid Body Formation from Singularized Human Embryonic Stem Cells
We report a technology to form human embryoid bodies (hEBs) from singularized human embryonic stem cells (hESCs) without the use of the p160 rho-associated coiled-coil kinase inhibitor (ROCKi) or centrifugation (spin). hEB formation was tested under four conditions: +ROCKi/+spin, +ROCKi/-spin, -ROCKi/+spin, and -ROCKi/-spin. Cell suspensions of BG01V/hOG and H9 hESC lines were pipetted into non-adherent hydrogel substrates containing defined microwell arrays. hEBs of consistent size and spherical geometry can be formed in each of the four conditions, including the -ROCKi/-spin condition. The hEBs formed under the -ROCKi/-spin condition differentiated to develop the three embryonic germ layers and tissues derived from each of the germ layers. This simplified hEB production technique offers homogeneity in hEB size and shape to support synchronous differentiation, elimination of the ROCKi xeno-factor and rate-limiting centrifugation treatment, and low-cost scalability, which will directly support automated, large-scale production of hEBs and hESC-derived cells needed for clinical, research, or therapeutic applications
Testing CPT- and Lorentz-odd electrodynamics with waveguides
We study CPT- and Lorentz-odd electrodynamics described by the Standard Model
Extension. Its radiation is confined to the geometry of hollow conductor
waveguide, open along . In a special class of reference frames, with
vanishing both 0-th and components of the background field, , we realize a number of {\em huge and macroscopically detectable}
effects on the confined waves spectra, compared to standard results.
Particularly, if points along (or ) direction only
transverse electric modes, with , should be observed propagating
throughout the guide, while all the transverse magnetic, , are absent.
Such a strong mode suppression makes waveguides quite suitable to probe these
symmetry violations using a simple and easily reproducible apparatus.Comment: 11pages, double-spacing, tex forma
Approach to Dyslipidemia, Lipodystrophy, and Cardiovascular Risk in Patients with HIV Infection
There is a significant prevalence (20%–80% depending on the population and the study) of lipid disorders and other cardiovascular risk factors in people living with HIV infection. This review focuses on HIV and HIV treatment–associated metabolic and cardiovascular concerns, including dyslipidemias, lipodystrophy syndromes, endothelial dysfunctions, and associated metabolic events such as insulin resistance. Emerging hypotheses of the underlying pathophysiology of these issues, with impact on selection of specific antiretroviral treatment (ART) strategies, therapy, and preventive approaches to decreasing cardiovascular risk and other problems associated with these syndromes are discussed. Screening for cardiovascular risk as part of the decision of starting antiretroviral therapy, and during care of patients with HIV regardless of ART therapy status, is suggested with particular areas of focus. Statins, other hyperlipidemic therapies, treatment for specific problems arising due to lipodystrophy, and implications on ART selection to avoid drug interactions and adverse effects are also discussed
HDAC3 role in medication consumption in medication overuse headache patients: a pilot study
C-Terminal Extension of the Yeast Mitochondrial DNA Polymerase Determines the Balance between Synthesis and Degradation
Saccharomyces cerevisiae mitochondrial DNA polymerase (Mip1) contains a C-terminal extension (CTE) of 279 amino acid residues. The CTE is required for mitochondrial DNA maintenance in yeast but is absent in higher eukaryotes. Here we use recombinant Mip1 C-terminal deletion mutants to investigate functional importance of the CTE. We show that partial removal of the CTE in Mip1Δ216 results in strong preference for exonucleolytic degradation rather than DNA polymerization. This disbalance in exonuclease and polymerase activities is prominent at suboptimal dNTP concentrations and in the absence of correctly pairing nucleotide. Mip1Δ216 also displays reduced ability to synthesize DNA through double-stranded regions. Full removal of the CTE in Mip1Δ279 results in complete loss of Mip1 polymerase activity, however the mutant retains its exonuclease activity. These results allow us to propose that CTE functions as a part of Mip1 polymerase domain that stabilizes the substrate primer end at the polymerase active site, and is therefore required for efficient mitochondrial DNA replication in vivo
What is known about the patient's experience of medical tourism? A scoping review
<p>Abstract</p> <p>Background</p> <p>Medical tourism is understood as travel abroad with the intention of obtaining non-emergency medical services. This practice is the subject of increasing interest, but little is known about its scope.</p> <p>Methods</p> <p>A comprehensive scoping review of published academic articles, media sources, and grey literature reports was performed to answer the question: what is known about the patient's experience of medical tourism? The review was accomplished in three steps: (1) identifying the question and relevant literature; (2) selecting the literature; (3) charting, collating, and summarizing the information. Overall themes were identified from this process.</p> <p>Results</p> <p>291 sources were identified for review from the databases searched, the majority of which were media pieces (<it>n </it>= 176). A further 57 sources were included for review after hand searching reference lists. Of the 348 sources that were gathered, 216 were ultimately included in this scoping review. Only a small minority of sources reported on empirical studies that involved the collection of primary data (<it>n </it>= 5). The four themes identified via the review were: (1) decision-making (e.g., push and pull factors that operate to shape patients' decisions); (2) motivations (e.g., procedure-, cost-, and travel-based factors motivating patients to seek care abroad); (3) risks (e.g., health and travel risks); and (4) first-hand accounts (e.g., patients' experiential accounts of having gone abroad for medical care). These themes represent the most discussed issues about the patient's experience of medical tourism in the English-language academic, media, and grey literatures.</p> <p>Conclusions</p> <p>This review demonstrates the need for additional research on numerous issues, including: (1) understanding how multiple information sources are consulted and evaluated by patients before deciding upon medical tourism; (2) examining how patients understand the risks of care abroad; (3) gathering patients' prospective and retrospective accounts; and (4) the push and pull factors, as well as the motives of patients to participate in medical tourism. The findings from this scoping review and the knowledge gaps it uncovered also demonstrate that there is great potential for new contributions to our understanding of the patient's experience of medical tourism.</p
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