41,441 research outputs found
A Complete Year of User Retrieval Sessions in a Social Sciences Academic Search Engine
In this paper, we present an open data set extracted from the transaction log
of the social sciences academic search engine sowiport. The data set includes a
filtered set of 484,449 retrieval sessions which have been carried out by
sowiport users in the period from April 2014 to April 2015. We propose a
description of interactions performed by the academic search engine users that
can be used in different applications such as result ranking improvement, user
modeling, query reformulation analysis, search pattern recognition.Comment: 6 pages, 2 figures, accepted short paper at the 21st International
Conference on Theory and Practice of Digital Libraries (TPDL 2017
Morphologies of protostellar outflows: An ALMA view
The formation of stars is usually accompanied by the launching of
protostellar outflows. Observations with the Atacama Large
Millimetre/sub-millimetre Array (ALMA) will soon revolutionalise our
understanding of the morphologies and kinematics of these objects. In this
paper, we present synthetic ALMA observations of protostellar outflows based on
numerical magnetohydrodynamic collapse simulations. We find significant
velocity gradients in our outflow models and a very prominent helical structure
within the outflows. We speculate that the disk wind found in the ALMA Science
Verification Data of HD 163296 presents a first instance of such an
observation
Characterizing anomalous diffusion in crowded polymer solutions and gels over five decades in time with variable-lengthscale fluorescence correlation spectroscopy
The diffusion of macromolecules in cells and in complex fluids is often found
to deviate from simple Fickian diffusion. One explanation offered for this
behavior is that molecular crowding renders diffusion anomalous, where the
mean-squared displacement of the particles scales as with . Unfortunately, methods such as
fluorescence correlation spectroscopy (FCS) or fluorescence recovery after
photobleaching (FRAP) probe diffusion only over a narrow range of lengthscales
and cannot directly test the dependence of the mean-squared displacement (MSD)
on time. Here we show that variable-lengthscale FCS (VLS-FCS), where the volume
of observation is varied over several orders of magnitude, combined with a
numerical inversion procedure of the correlation data, allows retrieving the
MSD for up to five decades in time, bridging the gap between diffusion
experiments performed at different lengthscales. In addition, we show that
VLS-FCS provides a way to assess whether the propagator associated with the
diffusion is Gaussian or non-Gaussian. We used VLS-FCS to investigate two
systems where anomalous diffusion had been previously reported. In the case of
dense cross-linked agarose gels, the measured MSD confirmed that the diffusion
of small beads was anomalous at short lengthscales, with a cross-over to simple
diffusion around m, consistent with a caged diffusion process.
On the other hand, for solutions crowded with marginally entangled dextran
molecules, we uncovered an apparent discrepancy between the MSD, found to be
linear, and the propagators at short lengthscales, found to be non-Gaussian.
These contradicting features call to mind the "anomalous, yet Brownian"
diffusion observed in several biological systems, and the recently proposed
"diffusing diffusivity" model
Classical and quantum anisotropic Heisenberg antiferromagnets
We study classical and quantum Heisenberg antiferromagnets with exchange
anisotropy of XXZ-type and crystal field single-ion terms of quadratic and
cubic form in a field. The magnets display a variety of phases, including the
spin-flop (or, in the quantum case, spin-liquid) and biconical (corresponding,
in the quantum lattice gas description, to supersolid) phases. Applying
ground-state considerations, Monte Carlo and density matrix renormalization
group methods, the impact of quantum effects and lattice dimension is analysed.
Interesting critical and multicritical behaviour may occur at quantum and
thermal phase transitions.Comment: 13 pages, 14 figures, conferenc
Fractal Markets Hypothesis and the Global Financial Crisis: Scaling, Investment Horizons and Liquidity
We investigate whether fractal markets hypothesis and its focus on liquidity
and invest- ment horizons give reasonable predictions about dynamics of the
financial markets during the turbulences such as the Global Financial Crisis of
late 2000s. Compared to the mainstream efficient markets hypothesis, fractal
markets hypothesis considers financial markets as com- plex systems consisting
of many heterogenous agents, which are distinguishable mainly with respect to
their investment horizon. In the paper, several novel measures of trading
activity at different investment horizons are introduced through scaling of
variance of the underlying processes. On the three most liquid US indices -
DJI, NASDAQ and S&P500 - we show that predictions of fractal markets hypothesis
actually fit the observed behavior quite well.Comment: 11 pages, 3 figure
Non-locality and Medium Effects in the Exclusive Photoproduction of Eta Mesons on Nuclei
A relativistic model for the quasifree exclusive photoproduction of
mesons on nuclei is extended to include both non-local and medium effects. The
reaction is assumed to proceed via the dominant contribution of the
S(1535) resonance. The complicated integrals resulting from the
non-locality are simplified using a modified version of a method given by
Cooper and Maxwell. The non-locality effects are found to affect the magnitude
of the cross section. Some possibilities reflecting the effects of the medium
on the propagation and properties of the intermediate S resonance are
studied. The effects of allowing the S to interact with the medium via
mean field scalar and vector potentials are considered. Both broadening of
width and reduction in mass of the resonance lead to a suppression of the
calculated cross sections.Comment: 19 pages, 7 figure
The Day After Tomorrows Doctors: UK Undergraduate Medical Student Resilience, Reports on the Symposium 2016
There is growing evidence that students and qualified doctors’ are experiencing high levels of workplace stress and burnout. Many medical students find student training and subsequently the transition to foundation year difficult. Medical schools have been tasked by the GMC to teach personal resilience as part of professional development. Despite this responsibility, it is far from clear whether medical schools have in fact integrated topics such as stress management, resilience training and self-care into their professional development curriculum. As far as we can establish this is the first meeting of UK medical educators to specifically address this topic
The calibration of photographic and spectroscopic films: Reciprocity failure and thermal responses of IIaO film at liquid nitrogen temperatures
Reciprocity failure was examined for IIaO spectroscopic film. The results indicate reciprocity failure occurs at three distinct minimum points in time; 15 min, 30 min and 90 min. The results are unique because theory suggests only one minimum reciprocity failure point should occur. When incubating 70mm IIaO film for 15 and 30 min at temperatures of 30, 40, 50, and 60 C and then placing in a liquid nitrogen bath at a temperature of -190 C the film demonstrated an increase of the optical density when developed at a warm-up time of 30 min. Longer warm-up periods of 1, 2 and 3 hrs yield a decrease in optical density of the darker wedge patterns; whereas, shorter warm-up times yield an overall increase in the optical densities
A Strategic Management Learning Laboratory: Integrating the College Classroom and the College Human Resource Management Environment
This capstone course extended the classroom to include practitioner-focused research projects and presentations to senior-level campus management. The course served as a student learning laboratory for experiencing working-world settings, problems, and expectations, using the controlled environment of a college human resource management office, working with the Director of Human Resource Management. Learning outcomes included 1) effectively using multiple business communication skills, 2) applying quantitative and qualitative reasoning for problem solving to integrate, synthesize and apply complex information for addressing practical problems; 3) experience in adapting to a real-life, changing environment, and 4) making management decisions that reflected the dynamic interrelationships of the major functions of business to achieve the mission of the organization. Finally, students reported a heightened sense of task identity, personal commitment to their college and their education, and a legacy of contribution for their role in helping shape human resource management policies for college governance
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