7,585 research outputs found
Dimensionality of spin modulations in 1/8-doped lanthanum cuprates from the perspective of NQR and muSR experiments
We investigate the dimensionality of inhomogeneous spin modulation patterns
in the cuprate family of high-temperature superconductors with particular focus
on 1/8-doped lanthanum cuprates. We compare one-dimensional stripe modulation
pattern with two-dimensional checkerboard of spin vortices in the context of
nuclear quadrupole resonance(NQR) and muon spin rotation(muSR) experiments. In
addition, we also consider the third pattern, a two-dimensional superposition
of spin spirals. Overall, we have found that none of the above patterns leads
to a consistent interpretation of the two types of experiments considered.
This, in particular, implies that the spin vortex checkerboard cannot be ruled
out on the basis of available NQR/muSR experimental results.Comment: 6 pages, 2 figure
A quantum group version of quantum gauge theories in two dimensions
For the special case of the quantum group we present an alternative approach to quantum gauge theories in
two dimensions. We exhibit the similarities to Witten's combinatorial approach
which is based on ideas of Migdal. The main ingredient is the Turaev-Viro
combinatorial construction of topological invariants of closed, compact
3-manifolds and its extension to arbitrary compact 3-manifolds as given by the
authors in collaboration with W. Mueller.Comment: 6 pages (plain TeX
Population Differences in Death Rates in HIV-Positive Patients with Tuberculosis.
SETTING: Randomised controlled clinical trial of Mycobacterium vaccae vaccination as an adjunct to anti-tuberculosis treatment in human immunodeficiency virus (HIV) positive patients with smear-positive tuberculosis (TB) in Lusaka, Zambia, and Karonga, Malawi. OBJECTIVE: To explain the difference in mortality between the two trial sites and to identify risk factors for death among HIV-positive patients with TB. DESIGN: Information on demographic, clinical, laboratory and radiographic characteristics was collected. Patients in Lusaka (667) and in Karonga (84) were followed up for an average of 1.56 years. Cox proportional hazard analyses were used to assess differences in survival between the two sites and to determine risk factors associated with mortality during and after anti-tuberculosis treatment. RESULTS: The case fatality rate was 14.7% in Lusaka and 21.4% in Karonga. The hazard ratio for death comparing Karonga to Lusaka was 1.47 (95% confidence interval [CI] 0.9-2.4) during treatment and 1.76 (95%CI 1.0-3.0) after treatment. This difference could be almost entirely explained by age and more advanced HIV disease among patients in Karonga. CONCLUSION: It is important to understand the reasons for population differences in mortality among patients with TB and HIV and to maximise efforts to reduce mortality
Assessing Human Error Against a Benchmark of Perfection
An increasing number of domains are providing us with detailed trace data on
human decisions in settings where we can evaluate the quality of these
decisions via an algorithm. Motivated by this development, an emerging line of
work has begun to consider whether we can characterize and predict the kinds of
decisions where people are likely to make errors.
To investigate what a general framework for human error prediction might look
like, we focus on a model system with a rich history in the behavioral
sciences: the decisions made by chess players as they select moves in a game.
We carry out our analysis at a large scale, employing datasets with several
million recorded games, and using chess tablebases to acquire a form of ground
truth for a subset of chess positions that have been completely solved by
computers but remain challenging even for the best players in the world.
We organize our analysis around three categories of features that we argue
are present in most settings where the analysis of human error is applicable:
the skill of the decision-maker, the time available to make the decision, and
the inherent difficulty of the decision. We identify rich structure in all
three of these categories of features, and find strong evidence that in our
domain, features describing the inherent difficulty of an instance are
significantly more powerful than features based on skill or time.Comment: KDD 2016; 10 page
Assessing Perceptions and Attitudes of an Extreme Sports Park
Action sports have been on the rise in the last decade. A new action sports park is considering developing operations on the east coast. The park would include extreme sports such as surfing, wakeboarding, and skating. The park will feature state of the art technologies that produce consistent waves for surfing 12 months a year. With over 10 million surfers worldwide the newest tourist attraction has been deemed appealing to the tourists that flock to the east coast and locals. Other possible amenities at the park include a family waterpark, dining, shopping, and nightlife opportunities. This study examines consumers’ perceptions of the new surf park
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