1,391 research outputs found
Rapid method for determination of antimicrobial susceptibilities pattern of urinary bacteria
Method determines bacterial sensitivity to antimicrobial agents by measuring level of adenosine triphosphate remaining in the bacteria. Light emitted during reaction of sample with a mixture of luciferase and luciferin is measured
Backbone of complex networks of corporations: The flow of control
We present a methodology to extract the backbone of complex networks based on
the weight and direction of links, as well as on nontopological properties of
nodes. We show how the methodology can be applied in general to networks in
which mass or energy is flowing along the links. In particular, the procedure
enables us to address important questions in economics, namely, how control and
wealth are structured and concentrated across national markets. We report on
the first cross-country investigation of ownership networks, focusing on the
stock markets of 48 countries around the world. On the one hand, our analysis
confirms results expected on the basis of the literature on corporate control,
namely, that in Anglo-Saxon countries control tends to be dispersed among
numerous shareholders. On the other hand, it also reveals that in the same
countries, control is found to be highly concentrated at the global level,
namely, lying in the hands of very few important shareholders. Interestingly,
the exact opposite is observed for European countries. These results have
previously not been reported as they are not observable without the kind of
network analysis developed here.Comment: 24 pages, 12 figures, 2nd version (text made more concise and
readable, results unchanged
Optimal treatment allocations in space and time for on-line control of an emerging infectious disease
A key component in controlling the spread of an epidemic is deciding where, whenand to whom to apply an intervention.We develop a framework for using data to informthese decisionsin realtime.We formalize a treatment allocation strategy as a sequence of functions, oneper treatment period, that map up-to-date information on the spread of an infectious diseaseto a subset of locations where treatment should be allocated. An optimal allocation strategyoptimizes some cumulative outcome, e.g. the number of uninfected locations, the geographicfootprint of the disease or the cost of the epidemic. Estimation of an optimal allocation strategyfor an emerging infectious disease is challenging because spatial proximity induces interferencebetween locations, the number of possible allocations is exponential in the number oflocations, and because disease dynamics and intervention effectiveness are unknown at outbreak.We derive a Bayesian on-line estimator of the optimal allocation strategy that combinessimulation–optimization with Thompson sampling.The estimator proposed performs favourablyin simulation experiments. This work is motivated by and illustrated using data on the spread ofwhite nose syndrome, which is a highly fatal infectious disease devastating bat populations inNorth America
Fragment Flow and the Nuclear Equation of State
We use the Boltzmann-Uehling-Uhlenbeck model with a momentum-dependent
nuclear mean field to simulate the dynamical evolution of heavy ion collisions.
We re-examine the azimuthal anisotropy observable, proposed as sensitive to the
equation of state of nuclear matter. We obtain that this sensitivity is maximal
when the azimuthal anisotropy is calculated for nuclear composite fragments, in
agreement with some previous calculations. As a test case we concentrate on
semi-central collisions at 400 MeV.Comment: 12 pages, ReVTeX 3.0. 12 Postscript figures, uuencoded and appende
Achieving Generalizable Robustness of Deep Neural Networks by Stability Training
We study the recently introduced stability training as a general-purpose
method to increase the robustness of deep neural networks against input
perturbations. In particular, we explore its use as an alternative to data
augmentation and validate its performance against a number of distortion types
and transformations including adversarial examples. In our image classification
experiments using ImageNet data stability training performs on a par or even
outperforms data augmentation for specific transformations, while consistently
offering improved robustness against a broader range of distortion strengths
and types unseen during training, a considerably smaller hyperparameter
dependence and less potentially negative side effects compared to data
augmentation.Comment: 18 pages, 25 figures; Camera-ready versio
Light depolarization effects in tip enhanced Raman spectroscopy of silicon (001) and gallium arsenide (001)
We report on the effects of light depolarization induced by sharp metallic tips in Tip-Enhanced Raman Spectroscopy (TERS). Experiments on Si(001) and GaAs(001) crystals show that the excitation field depolarization induces a selective enhancement of specific Raman modes, depending on their Raman tensor symmetry. A complete polarization analysis of the light backscattered from the tip confirms the TERS findings. The spatial confinement of the depolarization field is studied and its dependence on the excitation wavelength and power are explored
Combining active learning and semi-supervised learning techniques to extract protein interaction sentences
Background: Protein-protein interaction (PPI) extraction has been a focal point of many biomedical research and database curation tools. Both Active Learning and Semi-supervised SVMs have recently been applied to extract PPI automatically. In this paper, we explore combining the AL with the SSL to improve the performance of the PPI task. Methods: We propose a novel PPI extraction technique called PPISpotter by combining Deterministic Annealing-based SSL and an AL technique to extract protein-protein interaction. In addition, we extract a comprehensive set of features from MEDLINE records by Natural Language Processing (NLP) techniques, which further improve the SVM classifiers. In our feature selection technique, syntactic, semantic, and lexical properties of text are incorporated into feature selection that boosts the system performance significantly. Results: By conducting experiments with three different PPI corpuses, we show that PPISpotter is superior to the other techniques incorporated into semi-supervised SVMs such as Random Sampling, Clustering, and Transductive SVMs by precision, recall, and F-measure. Conclusions: Our system is a novel, state-of-the-art technique for efficiently extracting protein-protein interaction pairs.X116sciescopu
(Total) Vector Domination for Graphs with Bounded Branchwidth
Given a graph of order and an -dimensional non-negative
vector , called demand vector, the vector domination
(resp., total vector domination) is the problem of finding a minimum
such that every vertex in (resp., in ) has
at least neighbors in . The (total) vector domination is a
generalization of many dominating set type problems, e.g., the dominating set
problem, the -tuple dominating set problem (this is different from the
solution size), and so on, and its approximability and inapproximability have
been studied under this general framework. In this paper, we show that a
(total) vector domination of graphs with bounded branchwidth can be solved in
polynomial time. This implies that the problem is polynomially solvable also
for graphs with bounded treewidth. Consequently, the (total) vector domination
problem for a planar graph is subexponential fixed-parameter tractable with
respectto , where is the size of solution.Comment: 16 page
Long-term mortality after Histoplasma infection in people with HIV
Histoplasmosis is a common opportunistic infection in people with HIV (PWH); however, no study has looked at factors associated with the long-term mortality of histoplasmosis in PWH. We conducted a single-center retrospective study on the long-term mortality of PWH diagnosed with histoplasmosis between 2002 and 2017. Patients were categorized into three groups based on length of survival after diagnosis: early mortality (death \u3c 90 days), late mortality (death ≥ 90 days), and long-term survivors. Patients diagnosed during or after 2008 were considered part of the modern antiretroviral therapy (ART) era. Insurance type (private vs. public) was a surrogate indicator of socioeconomic status. Out of 54 PWH infected with histoplasmosis, overall mortality was 37%; 14.8% early mortality and 22.2% late mortality. There was no statistically significant difference in survival based on the availability of modern ART
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