1,388 research outputs found
Galaxy-scale Star Formation on the Red Sequence: the Continued Growth of S0s and the Quiescence of Ellipticals
This paper examines star formation (SF) in relatively massive, primarily
early-type galaxies (ETGs) at z~0.1. A sample is drawn from bulge-dominated
GALEX/SDSS galaxies on the optical red sequence with strong UV excess and yet
quiescent SDSS spectra. High-resolution far-UV imaging of 27 such ETGs using
HST ACS/SBC reveals structured UV morphology in 93% of the sample, consistent
with low-level ongoing SF (~0.5 Ms/yr). In 3/4 of the sample the SF is extended
on galaxy scales (25-75 kpc), while the rest contains smaller (5-15 kpc) SF
patches in the vicinity of an ETG - presumably gas-rich satellites being
disrupted. Optical imaging reveals that all ETGs with galaxy-scale SF in our
sample have old stellar disks (mostly S0 type). None is classified as a true
elliptical. In our sample, galaxy-scale SF takes the form of UV rings of
varying sizes and morphologies. For the majority of such objects we conclude
that the gas needed to fuel current SF has been accreted from the IGM, probably
in a prolonged, quasi-static manner, leading in some cases to additional disk
buildup. The remaining ETGs with galaxy-scale SF have UV and optical
morphologies consistent with minor merger-driven SF or with the final stages of
SF in fading spirals. Our analysis excludes that all recent SF on the red
sequence resulted from gas-rich mergers. We find further evidence that
galaxy-scale SF is almost exclusively an S0 phenomenon (~20% S0s have SF) by
examining the overall optically red SDSS ETGs. Conclusion is that significant
number of field S0s maintain or resume low-level SF because the preventive
feedback is not in place or is intermittent. True ellipticals, on the other
hand, stay entirely quiescent even in the field.Comment: Accepted for publication in ApJ. Contains color figures, but
compatible with non-color printer
Characterization of Salmonella enterica from invasive bloodstream infections and water sources in rural Ghana.
BACKGROUND: Non-typhoidal Salmonella (NTS) cause the majority of bloodstream infections in Ghana, however the mode of transmission and source of invasive NTS in Africa are poorly understood. This study compares NTS from water sources and invasive bloodstream infections in rural Ghana. METHODS: Blood from hospitalised, febrile children and samples from drinking water sources were analysed for Salmonella spp. Strains were serotyped to trace possible epidemiological links between human and water-derived isolates.. Antibiotic susceptibility testing was performed, RESULTS: In 2720 blood culture samples, 165 (6%) NTS were isolated. S. Typhimurium (70%) was the most common serovar followed by S. Enteritidis (8%) and S. Dublin (8%). Multidrug resistance (MDR) was found in 95 (58%) NTS isolates, including five S. Enteritidis. One S. Typhimurium showed reduced fluroquinolone susceptibility. In 511 water samples, 19 (4%) tested positive for S. enterica with two isolates being resistant to ampicillin and one isolate being resistant to cotrimoxazole. Serovars from water samples were not encountered in any of the clinical specimens. CONCLUSION: Water analyses demonstrated that common drinking water sources were contaminated with S. enterica posing a potential risk for transmission. However, a link between S. enterica from water sources and patients could not be established, questioning the ability of water-derived serovars to cause invasive bloodstream infections
The determinants of credit spreads changes in global shipping bonds.
yesThis paper investigates whether bond, issuer, industry and macro-specific variables
account for the observed variation of credit spreads’ changes of global shipping bond issues
before and after the onset of the subprime financial crisis. Results show that conclusions as
to the significant variables of spreads depend significantly on whether two-way clusteradjusted
standard errors are utilized, thus rendering results in the extant literature ambigious.
The main determinants of global cargo-carrying companies’ shipping bond spreads
are found in this paper to be: the liquidity of the bond issue, the stock market’s volatility,
the bond market’s cyclicality, freight earnings and the credit rating of the bond issue
Molecular Evidence for Flea-Borne Rickettsiosis in Febrile Patients from Madagascar.
Rickettsiae may cause febrile infections in humans in tropical and subtropical regions. From Madagascar, no molecular data on the role of rickettsioses in febrile patients are available. Blood samples from patients presenting with fever in the area of the capital Antananarivo were screened for the presence of rickettsial DNA. EDTA (ethylenediaminetetraacetic acid) blood from 1020 patients presenting with pyrexia > 38.5 °C was analyzed by gltA-specific qPCR. Positive samples were confirmed by ompB-specific qPCR. From confirmed samples, the gltA amplicons were sequenced and subjected to phylogenetic analysis. From five gltA-reactive samples, two were confirmed by ompB-specific qPCR. The gltA sequence in the sample taken from a 38-year-old female showed 100% homology with R. typhi. The other sample taken from a 1.5-year-old infant was 100% homologous to R. felis. Tick-borne rickettsiae were not identified. The overall rate of febrile patients with molecular evidence for a rickettsial infection from the Madagascan study site was 0.2% (2/1020 patients). Flea-borne rickettsiosis is a rare but neglected cause of infection in Madagascar. Accurate diagnosis may prompt adequate antimicrobial treatment
Recommended from our members
5-SPICE: the application of an original framework for community health worker program design, quality improvement and research agenda setting
Introduction: Despite decades of experience with community health workers (CHWs) in a wide variety of global health projects, there is no established conceptual framework that structures how implementers and researchers can understand, study and improve their respective programs based on lessons learned by other CHW programs. Objective: To apply an original, non-linear framework and case study method, 5-SPICE, to multiple sister projects of a large, international non-governmental organization (NGO), and other CHW projects. Design: Engaging a large group of implementers, researchers and the best available literature, the 5-SPICE framework was refined and then applied to a selection of CHW programs. Insights gleaned from the case study method were summarized in a tabular format named the ‘5×5-SPICE chart’. This format graphically lists the ways in which essential CHW program elements interact, both positively and negatively, in the implementation field. Results: The 5×5-SPICE charts reveal a variety of insights that come from a more complex understanding of how essential CHW projects interact and influence each other in their unique context. Some have been well described in the literature previously, while others are exclusive to this article. An analysis of how best to compensate CHWs is also offered as an example of the type of insights that this method may yield. Conclusions: The 5-SPICE framework is a novel instrument that can be used to guide discussions about CHW projects. Insights from this process can help guide quality improvement efforts, or be used as hypothesis that will form the basis of a program's research agenda. Recent experience with research protocols embedded into successfully implemented projects demonstrates how such hypothesis can be rigorously tested
Unexpected outcome from Trousseau syndrome
<p>Abstract</p> <p>Background</p> <p>Unprovoked superficial thrombophlebitis and subsequent venous thromboembolism are well-described albeit rare presenting features of advanced visceral malignancy that often manifest too late for curative intervention to be beneficial.</p> <p>Case Presentation</p> <p>We present the first reported case of early gastric carcinoma presenting with these paraneoplastic phenomena in an otherwise healthy farmer. The early presentation allowed for a curative partial gastrectomy, which itself was complicated by the presence of a deep vein thrombosis extending into the inferior vena cava. Fortunately, stabilization of the clot allowed for surgery to proceed without the need for a caval filter. The patient was referred for adjuvant chemotherapy and has since made an excellent recovery.</p> <p>Conclusions</p> <p>This case provides new evidence for the presentation of superficial thrombophlebitis in early gastric carcinoma and the potential for curative surgery in such instances. A high index of suspicion and a prompt diagnostic workup are essential for timely planning and execution of surgery in these early albeit rare presentations.</p
Loop Quantum Gravity a la Aharonov-Bohm
The state space of Loop Quantum Gravity admits a decomposition into
orthogonal subspaces associated to diffeomorphism equivalence classes of
spin-network graphs. In this paper I investigate the possibility of obtaining
this state space from the quantization of a topological field theory with many
degrees of freedom. The starting point is a 3-manifold with a network of
defect-lines. A locally-flat connection on this manifold can have non-trivial
holonomy around non-contractible loops. This is in fact the mathematical origin
of the Aharonov-Bohm effect. I quantize this theory using standard field
theoretical methods. The functional integral defining the scalar product is
shown to reduce to a finite dimensional integral over moduli space. A
non-trivial measure given by the Faddeev-Popov determinant is derived. I argue
that the scalar product obtained coincides with the one used in Loop Quantum
Gravity. I provide an explicit derivation in the case of a single defect-line,
corresponding to a single loop in Loop Quantum Gravity. Moreover, I discuss the
relation with spin-networks as used in the context of spin foam models.Comment: 19 pages, 1 figure; v2: corrected typos, section 4 expanded
Theory of Multidimensional Solitons
We review a number of topics germane to higher-dimensional solitons in
Bose-Einstein condensates. For dark solitons, we discuss dark band and planar
solitons; ring dark solitons and spherical shell solitons; solitary waves in
restricted geometries; vortex rings and rarefaction pulses; and multi-component
Bose-Einstein condensates. For bright solitons, we discuss instability,
stability, and metastability; bright soliton engineering, including pulsed atom
lasers; solitons in a thermal bath; soliton-soliton interactions; and bright
ring solitons and quantum vortices. A thorough reference list is included.Comment: review paper, to appear as Chapter 5a in "Emergent Nonlinear
Phenomena in Bose-Einstein Condensates: Theory and Experiment," edited by P.
G. Kevrekidis, D. J. Frantzeskakis, and R. Carretero-Gonzalez
(Springer-Verlag
Effect of local cold-pack application on systemic anabolic and inflammatory response to sprint-interval training: a prospective comparative trial
We evaluated the effect of cold ice-pack application following a brief sprint-interval training on the balance between anabolic mediators [growth hormone (GH), insulin-like growth factor-I (IGF-I), testosterone], catabolic markers (cortisol, IGFBP-1), and circulating pro [Interlukin-6 (IL-6) and IL-1β]- and anti-inflammatory cytokines [IL-1 receptor antagonist (IL-1ra)]. Twelve males, elite junior handball players performed 4 × 250 m treadmill run, at 80% of each individual’s maximal speed, followed by a rest period with and without local cold-pack application. Pre, immediately post, and 60-min post-exercise blood samples were drawn. Exercise was associated with a significant increase in IL-6, GH, IGFBP-3, and testosterone levels. Local cold-pack application was associated with significant decreases in IL-1β, IL-1ra, IGF-I, and IGFBP-3 and a greater increase of IGFBP-1 during recovery. Local ice therapy immediately following sprint-interval training was associated with greater decreases in both pro- and anti-inflammatory cytokines and anabolic hormones supporting some clinical evidence for possible negative effects on athletic performance
- …