434 research outputs found
Chlamydophila pneumoniae
AbstractChlamydophila pneumoniae infection is ubiquitous. It accounts for 10% of community-acquired pneumonias and 5% of cases of pharyngitis, bronchitis and sinusitis in both immunocompetent and immunocompromised hosts. It is also involved in exacerbations of chronic bronchitis and asthma. Moreover, C. pneumoniae has been reported as a possible cause of atherosclerosis and central nervous system disorders. The current reference standard for serological diagnosis of acute infection is microimmunofluorescence testing, although molecular detection techniques may well become reference diagnostic tests in the near future. Tetracyclines and erythromycin show good in vitro activity, and so far have been the most commonly employed drugs in the treatment of C. pneumoniae infection. New macrolides, ketolides and fluoroquinolones are other potentially effective drugs. This review analyses the most recent data concerning the involvement of C. pneumoniae in human diseases
Aperture Increase Options for the Dutch Open Telescope
This paper is an invitation to the international community to participate in
the usage and a substantial upgrade of the Dutch Open Telescope on La Palma
(DOT, \url{http://dot.astro.uu.nl}).
We first give a brief overview of the approach, design, and current science
capabilities of the DOT.
The DOT database (\url{http://dotdb.phys.uu.nl/DOT}) now contains many
tomographic image sequences with 0.2-0.3 arcsec resolution and up to multi-hour
duration. You are welcome to pull them over for analysis.
The main part of this contribution outlines DOT upgrade designs implementing
larger aperture. The motivation for aperture increase is the recognition that
optical solar physics needs the substantially larger telescope apertures that
became useful with the advent of adaptive optics and viable through the DOT's
open principle, both for photospheric polarimetry at high resolution and high
sensitivity and for chromospheric fine-structure diagnosis at high cadence and
full spectral sampling.
Realization of an upgrade requires external partnership(s). This report about
DOT upgrade options therefore serves also as initial documentation for
potential partners.Comment: in press,"Physics of Chromospheric Plasmas" (Coimbra), ASP 368, 573
(2007
The mass of the neutron star in SMC X-1
We present new optical spectroscopy of the eclipsing binary pulsar Sk 160/SMC
X-1. From the He I absorption lines, taking heating corrections into account,
we determine the radial velocity semi-amplitude of Sk 160 to be 21.8 +/- 1.8
km/s. Assuming Sk 160 fills its Roche-lobe, the inclination angle of the system
is i=65.3 deg +/- 1.3 deg and in this case we obtain upper limits for the mass
of the neutron star as Mx = 1.21 +/- 0.10 Msolar and for Sk 160 as Mo= 16.6 +/-
0.4 Msolar. However if we assume that the inclination angle is i=90 deg, then
the ratio of the radius of Sk 160 to the radius of its Roche-lobe is beta =
0.79 +/- 0.02, and the lower limits for the masses of the two stars are Mx =
0.91 +/- 0.08 Msolar and Mo = 12.5 +/- 0.1 Msolar. We also show that the HeII
4686A emission line tracks the motion of the neutron star, but with a radial
velocity amplitude somewhat less than that of the neutron star itself. We
suggest that this emission may arise from a hotspot where material accreting
via Roche lobe overflow impacts the outer edge of an accretion disc.Comment: Accepted for publication by A&A. 4 Figures & Table 2 will only appear
in the on-line versio
Migrations and habitat use of the smooth hammerhead shark (Sphyrna zygaena) in the Atlantic Ocean
The smooth hammerhead shark, Sphyrna zygaena, is a cosmopolitan semipelagic shark captured as bycatch in pelagic oceanic fisheries, especially pelagic longlines targeting swordfish and/or tunas. From 2012 to 2016, eight smooth hammerheads were tagged with Pop-up Satellite Archival Tags in the inter-tropical region of the Northeast Atlantic Ocean, with successful transmissions received from seven tags (total of 319 tracking days). Results confirmed the smooth hammerhead is a highly mobile species, as the longest migration ever documented for this species (> 6600 km) was recorded. An absence of a diel vertical movement behavior was noted, with the sharks spending most of their time at surface waters (0-50 m) above 23 degrees C. The operating depth of the pelagic long-line gear was measured with Minilog Temperature and Depth Recorders, and the overlap with the species vertical distribution was calculated. The overlap is taking place mainly during the night and is higher for juveniles (similar to 40% of overlap time). The novel information presented can now be used to contribute to the provision of sustainable management tools and serve as input for Ecological Risk Assessments for smooth hammerheads caught in Atlantic pelagic longline fisheries.Oceanario de Lisboa through Project "SHARK-TAG: Migrations and habitat use of the smooth hammerhead shark in the Atlantic Ocean"; Investigador-FCT from the Portuguese Foundation for Science and Technology (FCT, Fundacao para a Ciencia e Tecnologia) [Ref: IF/00253/2014]; EU European Social Fund; Programa Operacional Potencial Human
3D visualization processes for recreating and studying organismal form
The study of biological form is a vital goal of evolutionary biology and functional morphology. We review an emerging set of methods that allow scientists to create and study accurate 3D models of living organisms and animate those models for biomechanical and fluid dynamic analyses. The methods for creating such models include 3D photogrammetry, laser and CT-scanning, and 3D software. New multi-camera devices can be used to create accurate 3D models of living animals in the wild and captivity. New websites and virtual reality/augmented reality devices now enable the visualization and sharing of these data. We provide examples of these approaches for animals ranging from large whales to lizards and show applications for several areas: Natural history collections; body condition/scaling, bioinspired robotics, computational fluids dynamics (CFD), machine learning, and education. We provide two data sets to demonstrate the efficacy of CFD and machine learning approaches and conclude with a prospectus
Imaging-guided chest biopsies: techniques and clinical results
Background
This article aims to comprehensively describe indications, contraindications, technical aspects, diagnostic accuracy and complications of percutaneous lung biopsy.
Methods
Imaging-guided biopsy currently represents one of the predominant methods for obtaining tissue specimens in patients with lung nodules; in many cases treatment protocols are based on histological information; thus, biopsy is frequently performed, when technically feasible, or in case other techniques (such as bronchoscopy with lavage) are inconclusive.
Results
Although a coaxial system is suitable in any case, two categories of needles can be used: fine-needle aspiration biopsy (FNAB) and core-needle biopsy (CNB), with the latter demonstrated to have a slightly higher overall sensitivity, specificity and accuracy.
Conclusion
Percutaneous lung biopsy is a safe procedure even though a few complications are possible: pneumothorax, pulmonary haemorrhage and haemoptysis are common complications, while air embolism and seeding are rare, but potentially fatal complications
On the nature of the galactic early-B hypergiants
Despite their importance to a number of astrophysical fields, the lifecycles
of very massive stars are still poorly defined. In order to address this
shortcoming, we present a detailed quantitative study of the physical
properties of four early-B hypergiants (BHGs); Cyg OB2 #12, zeta Sco, HD190603
and BP Cru. These are combined with an analysis of their long-term
spectroscopic and photometric behaviour in order to determine their
evolutionary status. The long-term datasets revealed that they are remarkably
stable over long periods (>40yr), with the possible exception of zeta Sco prior
to the 20th century, in contrast to the typical excursions that characterise
luminous blue variables (LBVs). Zeta Sco, HD190603 and BP Cru possess physical
properties intermediate between B supergiants and LBVs; we therefore suggest
that BHGs are the immediate descendants and progenitors (respectively) of such
stars (for initial masses in the range ~30-60Msun). In contrast, while the wind
properties of Cyg OB2 #12 are consistent with this hypothesis, the combination
of extreme luminosity and spectroscopic mass (~110Msun) and comparatively low
temperature means it cannot be accommodated in such a scheme. Likewise, despite
its co-location with several LBVs above the Humphreys-Davidson (HD) limit, the
lack of long term variability and its unevolved chemistry apparently excludes
such an identification. Since such massive stars are not expected to evolve to
such cool temperatures, the properties of Cyg OB2 #12 are difficult to
understand under current evolutionary paradigms. [ABRIDGED]Comment: 36 pages, 19 figures (of which 17 pages are online supplemental
material). Accepted for publication in Astronomy and Astrophysic
Radio Astronomy
Contains reports on five research projects.National Science Foundation (Grant AST82-14296)National Aeronautics and Space Administration (Grant NAG W-373)National Aeronautics and Space Administration (Grant NAG5-537)U.S. Navy - Office of Naval Research (Contract N00014-84-C-2082)SM Systems and Research, Inc.Defense Advanced Research Project Agency (Contract MDA903-82-K-0521
- …