720 research outputs found
Three coronary arteries arising from the right coronary cusp with a malignant sub-pulmonary course of the left anterior descending artery
AbstractWe describe a case of a 45-year-old man presenting with acute myocardial infarction investigated by computed tomography coronary angiography. Interestingly all three coronary arteries arose from the right coronary cusp. The left anterior descending artery (LAD) subtended an acute angle from the aortic root, associated with significant kinking and stenosis at the ostium, before passing anteriorly, taking a sub-pulmonic course and descending in the anterior interventricular groove. The distal vessel was small with an atrophic appearance. The circumflex artery followed a retro-aortic route, before trifurcating to supply the lateral and posterior walls of the left ventricle. The right coronary artery was normal. Given his unstable presentation and the potentially lethal course of the LAD, he was referred for grafting of the LAD vessel which successfully ameliorated his symptoms and has thus far prevented recurrent myocardial infarction.<Learning objective: Computed tomography coronary angiography is becoming increasingly accessible to physicians for the investigation of patients with suspected coronary disease and the planning of surgery. As such, coronary anomalies are likely to be encountered more frequently, and it is important to appreciate their clinical significance.
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Extensional Tectonics in the Jeanne d'Arc Basin, Offshore Newfoundland: Implications for the Timing of Break-Up between Grand Banks and Iberia
Using seismic reflection and exploratory well data from the Jeanne d’Arc basin, offshore Newfoundland, we examined the link between unconformity generation and the onset of seafloor spreading between the central Grand Banks and Iberia. A prominent unconformity developed across the entire basin, previously interpreted as a ‘break-up’ unconformity, is reinterpreted as a late Barremian/early Aptian rift-onset unconformity on the basis of the stratal geometry and lithofacies. The rotation and divergence of seismic reflectors above this unconformity attest to differential subsidence documenting an episode of extension and block rotation within the basin at this time. Our seismic sequence analysis suggests that rifting and block rotation continued in the Jeanne d’Arc basin until at least late Aptian/early Albian time.
The onset of seafloor spreading between the central Grand Banks and Iberia is uncertain because of limited marine magnetic and drilling data (ODP and DSDP), and the existence of the Cretaceous magnetic quiet zone along the margin. However, recent studies indicate that magnetic anomaly M0 (118 Ma) is not well resolved north of the Newfoundland Seamounts within the Newfoundland basin and is not present north of the Figueiro fracture zone along the conjugate Iberian margin. This suggests that seafloor spreading between the northern portion of the Newfoundland basin and the northern Iberian margin began after the early Aptian. Given that the cessation of rifting marks the onset of seafloor spreading our seismic sequence analysis indicates that the onset of seafloor spreading in the northern Newfoundland basin, north of the Newfoundland Seamounts, began after late Aptian time
The [O II] lambda 3727 Luminosity Function at z ~ 1
We measure the evolution of the [OII]lambda 3727 luminosity function at
0.75<z<1.45 using high-resolution spectroscopy of ~14,000 galaxies observed by
the DEEP2 galaxy redshift survey. We find that brighter than L_{OII}=10^{42}
erg s^(-1) the luminosity function is well-represented by a power law dN/dL ~
L^{\alpha} with slope \alpha ~ -3. The number density of [OII] emitting
galaxies above this luminosity declines by a factor of >~2.5 between z ~ 1.35
and z ~ 0.84. In the limit of no number-density evolution, the characteristic
[OII] luminosity, L^*_[OII], defined as the luminosity where the space density
equals 10^{-3.5} dex^{-1} Mpc^{-3}, declines by a factor of ~1.8 over the same
redshift interval. Assuming that L_[OII] is proportional to the star-formation
rate (SFR), and negligible change in the typical dust attenuation in galaxies
at fixed [OII] luminosity, the measured decline in L^*_[OII] implies a ~25% per
Gyr decrease in the amount of star formation in galaxies during this epoch.
Adopting a faint-end power-law slope of -1.3\pm0.2, we derive the comoving SFR
density in four redshift bins centered around z~1 by integrating the observed
[OII] luminosity function using a local, empirical calibration between L_[OII]
and SFR, which statistically accounts for variations in dust attenuation and
metallicity among galaxies. We find that our estimate of the SFR density at z~1
is consistent with previous measurements based on a variety of independent SFR
indicators.Comment: 10 pages, 6 figures, 2 tables, resubmitted to ApJ, in emulateapj
style. Comparison with narrow-band observations added. Wavelength coverage
included into complete function, little effects. The data is available on
http://bias.cosmo.fas.nyu.edu/galevolution
BioNetGen 2.2: Advances in Rule-Based Modeling
BioNetGen is an open-source software package for rule-based modeling of
complex biochemical systems. Version 2.2 of the software introduces numerous
new features for both model specification and simulation. Here, we report on
these additions, discussing how they facilitate the construction, simulation,
and analysis of larger and more complex models than previously possible.Comment: 3 pages, 1 figure, 1 supplementary text file. Supplementary text
includes a brief discussion of the RK-PLA along with a performance analysis,
two tables listing all new actions/arguments added in BioNetGen 2.2, and the
"BioNetGen Quick Reference Guide". Accepted for publication in Bioinformatic
Globular Clusters in Dense Clusters of Galaxies
Deep imaging data from the Keck II telescope are employed to study the
globular cluster (GC) populations in the cores of six rich Abell clusters. The
sample includes A754, A1644, A2124, A2147, A2151, and A2152, and spans the
redshift range z = 0.035-0.066. The clusters also range in morphology from
spiral-rich, irregular systems to centrally concentrated cD clusters rich in
early-type galaxies. Globular cluster specific frequencies S_N and luminosity
function dispersions are measured for a total of 9 galaxies in six central
fields. The measured values of S_N for the six brightest cluster galaxies
(BCGs) are all higher than typical values for giant ellipticals, in accord with
the known S_N-density correlations. The three non-BCGs analyzed also have
elevated values of S_N, confirming that central location is a primary factor.
The number of GCs per unit mass for these fields are consistent with those
found in an earlier sample, giving further evidence that GC number scales with
mass and that the S_N variations are due to a deficit of halo light, i.e., S_N
reflects mass-to-light ratio.
The discussion builds on an earlier suggestion that the GCs (both metal rich
and metal poor) around the central cluster galaxies were assembled at early
times, and that star formation halted prematurely in the central galaxies at
the epoch of cluster collapse. This is consistent with recent simulations of
BCG/cluster formation. The subsequent addition of luminous material through
cluster dynamical evolution can cause S_N to decrease, and we may be seeing the
first evidence of this. Finally, the GC luminosity function measurements are
used to constrain the relative distances of the three clusters that make up the
Hercules supercluster.Comment: Uses emulateapj.sty (included); 17 pages with 9 included PostScript
figures. Figures 1-6 are separate GIF images (so 15 figures total) available
from http://astro.caltech.edu/~jpb/clusters -- the full PostScript version of
the paper (20 pages; 2.2 Mb compressed) incorporating Figures 1-6 can also be
grabbed from this URL. Accepted for publication in A
The New Zealand Kauri (Agathis Australis) Research Project: A Radiocarbon Dating Intercomparison of Younger Dryas Wood and Implications for IntCal13
We describe here the New Zealand kauri (Agathis australis) Younger Dryas (YD) research project, which aims to undertake Δ14C analysis of ~140 decadal floating wood samples spanning the time interval ~13.1–11.7 kyr cal BP. We report 14C intercomparison measurements being undertaken by the carbon dating laboratories at University of Waikato (Wk), University of California at Irvine (UCI), and University of Oxford (OxA). The Wk, UCI, and OxA laboratories show very good agreement with an interlaboratory comparison of 12 successive decadal kauri samples (average offsets from consensus values of –7 to +4 14C yr). A University of Waikato/University of Heidelberg (HD) intercomparison involving measurement of the YD-age Swiss larch tree Ollon505, shows a HD/Wk offset of ~10–20 14C yr (HD younger), and strong evidence that the positioning of the Ollon505 series is incorrect, with a recommendation that the 14C analyses be removed from the IntCal calibration database
General practitioners' views on reattribution for patients with medically unexplained symptoms: a questionnaire and qualitative study
Background:
The successful introduction of new methods for managing medically unexplained symptoms in primary care is dependent to a large degree on the attitudes, experiences and expectations of practitioners. As part of an exploratory randomised controlled trial of reattribution training, we sought the views of participating practitioners on patients with medically unexplained symptoms, and on the value of and barriers to the implementation of reattribution in practice.
Methods:
A nested attitudinal survey and qualitative study in sixteen primary care teams in north-west England. All practitioners participating in the trial (n = 74) were invited to complete a structured survey. Semi-structured interviews were undertaken with a purposive sub-sample of survey respondents, using a structured topic guide. Interview transcripts were used to identify key issues, concepts and themes, which were grouped to construct a conceptual framework: this framework was applied systematically to the data.
Results:
Seventy (95%) of study participants responded to the survey. Survey respondents often found it stressful to work with patients with medically unexplained symptoms, though those who had received reattribution training were more optimistic about their ability to help them. Interview participants trained in reattribution (n = 12) reported that reattribution increased their confidence to practice in a difficult area, with heightened awareness, altered perceptions of these patients, improved opportunities for team-building and transferable skills. However general practitioners also reported potential barriers to the implementation of reattribution in routine clinical practice, at the level of the patient, the doctor, the consultation, diagnosis and the healthcare context.
Conclusion:
Reattribution training increases practitioners' sense of competence in managing patients with medically unexplained symptoms. However, barriers to its implementation are considerable, and frequently lie outside the control of a group of practitioners generally sympathetic to patients with medically unexplained symptoms and the purpose of reattribution. These findings add further to the evidence of the difficulty of implementing reattribution in routine general practice
Digital Bridges Across Disciplinary, Practical and Pedagogical Divides: An Online Professional Master’s Program in Heritage Resource Management
Growth and diversification in heritage resource management (HRM) archaeology since the 1960s have created new demands for training the next generations of HRM leaders and for addressing persistent and counterproductive divisions between academic and applied archaeologies. The Simon Fraser University Department of Archaeology (SFU) has responded to these demands with an all-new, cohort-based, thesis-focused graduate program created by and for HRM professionals. The program’s target audience is HRM practitioners who hold Bachelor’s credentials, have initiated promising careers in HRM, and desire advanced, research-focused degrees to enable their professional capacity and upward mobility. The SFU program is structured and focused to provide intensive, predominantly online training in the four essential dimensions of HRM: law and policy, ethics and practice, business management, and research design and methods. The program has been successful through initial cohort cycles and in attracting HRM industry interest in collaboration. Industry-academic partnerships in cognate disciplines have proved effective in comparable circumstances but remain underdeveloped as bases for planning and delivering state-of-the-art training in applied archaeology and the broader field of HRM. Critical next steps in program development entail the identification of attributes of HRM futures desired by all or most HRM stakeholders and the collaborative pursuit of those desired futures
What happens if you single out? An experiment
We present an experiment investigating the effects of singling out an individual on trust and trustworthiness. We find that (a) trustworthiness falls if there is a singled out subject; (b) non-singled out subjects discriminate against the singled out subject when they are not responsible of the distinct status of this person; (c) under a negative frame, the singled out subject returns significantly less; (d) under a positive frame, the singled out subject behaves bimodally, either selecting very low or very high return rates. Overall, singling out induces a negligible effect on trust but is potentially disruptive for trustworthiness
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