2,234 research outputs found
'Leaving town' versus 'taking leave': the case for re-thinking academic leave restrictions
published_or_final_versio
Prostate Cancer and Race
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72215/1/j.1525-1497.2003.30801.x.pd
A trapped single ion inside a Bose-Einstein condensate
Improved control of the motional and internal quantum states of ultracold
neutral atoms and ions has opened intriguing possibilities for quantum
simulation and quantum computation. Many-body effects have been explored with
hundreds of thousands of quantum-degenerate neutral atoms and coherent
light-matter interfaces have been built. Systems of single or a few trapped
ions have been used to demonstrate universal quantum computing algorithms and
to detect variations of fundamental constants in precision atomic clocks. Until
now, atomic quantum gases and single trapped ions have been treated separately
in experiments. Here we investigate whether they can be advantageously combined
into one hybrid system, by exploring the immersion of a single trapped ion into
a Bose-Einstein condensate of neutral atoms. We demonstrate independent control
over the two components within the hybrid system, study the fundamental
interaction processes and observe sympathetic cooling of the single ion by the
condensate. Our experiment calls for further research into the possibility of
using this technique for the continuous cooling of quantum computers. We also
anticipate that it will lead to explorations of entanglement in hybrid quantum
systems and to fundamental studies of the decoherence of a single, locally
controlled impurity particle coupled to a quantum environment
Rapid assessment of myocardial infarct size in rodents using multi-slice inversion recovery late gadolinium enhancement CMR at 9.4T
Background: Myocardial infarction (MI) can be readily assessed using late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR). Inversion recovery (IR) sequences provide the highest contrast between enhanced infarct areas and healthy myocardium. Applying such methods to small animals is challenging due to rapid respiratory and cardiac rates relative to T-1 relaxation.Methods: Here we present a fast and robust protocol for assessing LGE in small animals using a multi-slice IR gradient echo sequence for efficient assessment of LGE. An additional Look-Locker sequence was used to assess the optimum inversion point on an individual basis and to determine most appropriate gating points for both rat and mouse. The technique was applied to two preclinical scenarios: i) an acute (2 hour) reperfused model of MI in rats and ii) mice 2 days following non-reperfused MI.Results: LGE images from all animals revealed clear areas of enhancement allowing for easy volume segmentation. Typical inversion times required to null healthy myocardium in rats were between 300-450 ms equivalent to 2-3 R-waves and similar to 330 ms in mice, typically 3 R-waves following inversion. Data from rats was also validated against triphenyltetrazolium chloride staining and revealed close agreement for infarct size.Conclusion: The LGE protocol presented provides a reliable method for acquiring images of high contrast and quality without excessive scan times, enabling higher throughput in experimental studies requiring reliable assessment of MI
Balanced Schnyder woods for planar triangulations: an experimental study with applications to graph drawing and graph separators
In this work we consider balanced Schnyder woods for planar graphs, which are
Schnyder woods where the number of incoming edges of each color at each vertex
is balanced as much as possible. We provide a simple linear-time heuristic
leading to obtain well balanced Schnyder woods in practice. As test
applications we consider two important algorithmic problems: the computation of
Schnyder drawings and of small cycle separators. While not being able to
provide theoretical guarantees, our experimental results (on a wide collection
of planar graphs) suggest that the use of balanced Schnyder woods leads to an
improvement of the quality of the layout of Schnyder drawings, and provides an
efficient tool for computing short and balanced cycle separators.Comment: Appears in the Proceedings of the 27th International Symposium on
Graph Drawing and Network Visualization (GD 2019
Measuring co-authorship and networking-adjusted scientific impact
Appraisal of the scientific impact of researchers, teams and institutions
with productivity and citation metrics has major repercussions. Funding and
promotion of individuals and survival of teams and institutions depend on
publications and citations. In this competitive environment, the number of
authors per paper is increasing and apparently some co-authors don't satisfy
authorship criteria. Listing of individual contributions is still sporadic and
also open to manipulation. Metrics are needed to measure the networking
intensity for a single scientist or group of scientists accounting for patterns
of co-authorship. Here, I define I1 for a single scientist as the number of
authors who appear in at least I1 papers of the specific scientist. For a group
of scientists or institution, In is defined as the number of authors who appear
in at least In papers that bear the affiliation of the group or institution. I1
depends on the number of papers authored Np. The power exponent R of the
relationship between I1 and Np categorizes scientists as solitary (R>2.5),
nuclear (R=2.25-2.5), networked (R=2-2.25), extensively networked (R=1.75-2) or
collaborators (R<1.75). R may be used to adjust for co-authorship networking
the citation impact of a scientist. In similarly provides a simple measure of
the effective networking size to adjust the citation impact of groups or
institutions. Empirical data are provided for single scientists and
institutions for the proposed metrics. Cautious adoption of adjustments for
co-authorship and networking in scientific appraisals may offer incentives for
more accountable co-authorship behaviour in published articles.Comment: 25 pages, 5 figure
Volume-Targeted Ventilation and Arterial Carbon Dioxide in Neonates
Objectives: To review the arterial carbon dioxide tensions (PaCO2) in newborn infants ventilated using synchronized intermittent mandatory ventilation (SIMV) in volume guarantee mode (using the Drager Babylog 8000+) with a unit policy targeting tidal volumes of approximately 4 mL/kg. Methods: Data on ventilator settings and arterial (PaCO2 levels were collected on all arterial blood gases (ABG; n = 288) from 50 neonates ( 65 mmHg) were determined. Results: The mean (SD) (PaCO2 during the first 48 h was 46.6 (9.0) mmHg. The mean (SD) (PaCO2 on the first blood gas of those infants commenced on volume guarantee from admission was 45.1 (12.5) mmHg. Severe hypo- or hypercapnoea occurred in 8% of infants at the time of their first blood gas measurement, and i
Strategically Equivalent Contests
Using a two-player Tullock-type contest, we show that intuitively and structurally different contests can be strategically equivalent. Strategically equivalent contests generate the same best response functions and, as a result, the same equilibrium efforts. However, strategically equivalent contests may yield different equilibrium payoffs. We propose a simple two-step procedure to identify strategically equivalent contests. Using this procedure, we identify contests that are strategically equivalent to the original Tullock contest, and provide new examples of strategically equivalent contests. Finally, we discuss possible contest design applications and avenues for future theoretical and empirical research
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