769 research outputs found
Outlier Edge Detection Using Random Graph Generation Models and Applications
Outliers are samples that are generated by different mechanisms from other
normal data samples. Graphs, in particular social network graphs, may contain
nodes and edges that are made by scammers, malicious programs or mistakenly by
normal users. Detecting outlier nodes and edges is important for data mining
and graph analytics. However, previous research in the field has merely focused
on detecting outlier nodes. In this article, we study the properties of edges
and propose outlier edge detection algorithms using two random graph generation
models. We found that the edge-ego-network, which can be defined as the induced
graph that contains two end nodes of an edge, their neighboring nodes and the
edges that link these nodes, contains critical information to detect outlier
edges. We evaluated the proposed algorithms by injecting outlier edges into
some real-world graph data. Experiment results show that the proposed
algorithms can effectively detect outlier edges. In particular, the algorithm
based on the Preferential Attachment Random Graph Generation model consistently
gives good performance regardless of the test graph data. Further more, the
proposed algorithms are not limited in the area of outlier edge detection. We
demonstrate three different applications that benefit from the proposed
algorithms: 1) a preprocessing tool that improves the performance of graph
clustering algorithms; 2) an outlier node detection algorithm; and 3) a novel
noisy data clustering algorithm. These applications show the great potential of
the proposed outlier edge detection techniques.Comment: 14 pages, 5 figures, journal pape
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Effects of Age and Sex on Inspiratory Muscle Activation Patterns During Exercise
Purpose: Characterize the effects of age, sex, and their interaction on inspiratory muscle
activation patterns during exercise. Methods: Twenty younger (20-30y, n=10 women) and
twenty older (60-80y, n=10 women) subjects performed an incremental cycle exercise test.
Electromyography of the scalene (EMGsca) and sternocleidomastoid (EMGscm) muscles were
measured using skin surface electrodes, while diaphragm electromyography (EMGdi) and
esophageal and transdiaphragmatic pressures were measured using an esophageal catheter.
Electromyography data were transformed into root-mean-square with a 100ms time constant.
Esophageal (PTPes) and diaphragmatic (PTPdi) pressure-time products were used as indices of
total inspiratory muscle pressure production and diaphragmatic pressure production,
respectively. Results: At absolute minute ventilations (V
E), women and older subjects had
greater EMGdi than men and younger subjects, respectively (all p<0.05), but no differences were
noted when V
E was expressed in relative terms (all p>0.05). Women had greater EMGsca activity
than men at absolute and relative levels of V
E (all p<0.05). Older subjects had greater EMGsca
than younger subjects when V
E was expressed relative (all p<0.05) but not absolute terms (all
p>0.05). At absolute and relative levels of V
E, women and older subjects had greater EMGscm
than men and younger subjects, respectively (all p<0.05). Women and older subjects had a
greater PTPdi/PTPes at a V
E of 70 l·min-1 than men and younger subjects, respectively (both
p<0.05), but no differences were noted when V
E was expressed in relative terms (all p>0.05). No
significant interactions between age and sex were noted (all p>0.05). Conclusion: Age and sex
significantly affect inspiratory muscle activation patterns during exercise; however, the extent of
the effects depends on whether comparisons are made at a solute or relative V
E.This study was supported by the British Columbia Lung Association
(BCLA). YMS, PBD, and AHR were supported by graduate scholarships from the Natural
Sciences and Engineering Research Council of Canada (NSERC). PBD and MRS were
supported by fellowships from the University of British Columbia and BCLA. JAG was
supported by a Scholar Award from the Michael Smith Foundation for Health Research, a New
Investigator Award from the Providence Health Care Research Institute and St. Paul’s Hospital
Foundation, and a Canadian Institutes of Health Research Clinical Rehabilitation New Investigator Award
Wall Crossing, Quivers and Crystals
We study the spectrum of BPS D-branes on a Calabi-Yau manifold using the 0+1
dimensional quiver gauge theory that describes the dynamics of the branes at
low energies. The results of Kontsevich and Soibelman predict how the
degeneracies change. We argue that Seiberg dualities of the quiver gauge
theories, which change the basis of BPS states, correspond to crossing the
"walls of the second kind." There is a large class of examples, including local
del Pezzo surfaces, where the BPS degeneracies of quivers corresponding to one
D6 brane bound to arbitrary numbers of D4, D2 and D0 branes are counted by
melting crystal configurations. We show that the melting crystals that arise
are a discretization of the Calabi-Yau geometry. The shape of the crystal is
determined by the Calabi-Yau geometry and the background B-field, and its
microscopic structure by the quiver Q. We prove that the BPS degeneracies
computed from Q and Q' are related by the Kontsevich Soibelman formula, using a
geometric realization of the Seiberg duality in the crystal. We also show that,
in the limit of infinite B-field, the combinatorics of crystals arising from
the quivers becomes that of the topological vertex. We thus re-derive the
Gromov-Witten/Donaldson-Thomas correspondence
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Manipulation of mechanical ventilatory constraint during moderate intensity exercise does not influence dyspnoea in healthy older men and women
© 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society. KEY POINT SUMMARY:The perceived intensity of exertional breathlessness (i.e. dyspnoea) is higher in older women than in older men, possibly due to sex-difference respiratory system morphology. During exercise at a given absolute intensity or minute ventilation, older women have a greater degree of mechanical ventilatory constraint (i.e. work of breathing and expiratory flow limitation) than their male counterparts, which may lead to a greater perceived intensity of dyspnoea. Using a single-blind randomized study design, we experimentally manipulated the magnitude of mechanical ventilatory constraint during moderate-intensity exercise at ventilatory threshold in healthy older men and women. We found that changes in the magnitude of mechanical ventilatory constraint within the physiological range had no effect on dyspnoea in healthy older adults. When older men and women perform submaximal exercise at a moderate intensity, mechanical ventilatory constraint does not contribute significantly to the sensation of dyspnoea. We sought to determine the effect of manipulating mechanical ventilatory constraint during submaximal exercise on dyspnoea in older men and women. METHODS:Eighteen healthy subjects (60-80 y; 9 men, 9 women) completed two days of testing. On Day 1, subjects performed pulmonary function testing and a maximal incremental cycle exercise test. On Day 2, subjects performed three 6-min bouts of cycling at ventilatory threshold, in a single-blind randomized manner, while breathing: i) normoxic helium-oxygen (HEL) to reduce the work of breathing (Wb ) and alleviate expiratory flow limitation (EFL); ii) through an inspiratory resistance (RES) of ∼5 cmH2 O·l-1 ·s-1 to increase Wb ; and iii) ambient air as a control (CON). Oesophageal pressure, diaphragm electromyography, and sensory responses (using the category-ratio 10 Borg scale) were monitored throughout exercise. RESULTS:During the HEL condition, there was a significant decrease in Wb (men: -21 ± 6%, women: -17 ± 10%) relative to CON (both p < 0.01). Moreover, if EFL was present during CON (4 men, 5 women), it was alleviated during HEL. Conversely, during the RES condition, Wb (men: 42 ± 19%, women: 50 ± 16%) significantly increased relative to CON (both p < 0.01). There was no main effect of sex on Wb (p = 0.59). Across conditions, women reported significantly higher dyspnoea intensity than men (2.9 ± 0.9 vs. 1.9 ± 0.8 Borg scale units, p < 0.05). Despite significant differences in the degree of mechanical ventilatory constraint between conditions, dyspnoea intensity was unaffected, independent of sex (p = 0.46). CONCLUSION:When older men and women perform submaximal exercise at a moderate intensity, mechanical ventilatory constraint does not contribute significantly to the sensation of dyspnoea. This article is protected by copyright. All rights reserved.Natural Science and Engineering Research Council of Canada (NSERC)
British Columbia Lung Association (BCLA
Deconstructing, Addressing, and Eliminating Racial and Ethnic Inequities in Prostate Cancer Care
Context
Men of African ancestry have demonstrated markedly higher rates of prostate cancer mortality than men of other races and ethnicities around the world. In fact, the highest rates of prostate cancer mortality worldwide are found in the Caribbean and Sub-Saharan West Africa, and among men of African descent in the USA. Addressing this inequity in prostate cancer care and outcomes requires a focused research approach that creates durable solutions to address the structural, social, environmental, and health factors that create racial disparities in care and outcomes.
Objective
To introduce a conceptual model for evaluating racial inequities in prostate cancer care to facilitate the development of translational research studies and interventions.
Evidence acquisition
A collaborative review of literature relevant to racial inequities in prostate cancer care and outcomes was performed. Existing literature was used to highlight various components of the conceptual model to inform future research and interventions toward equitable care and outcomes.
Evidence synthesis
Racial inequities in prostate cancer outcomes are driven by a series of structural and social determinants of health that impact exposures, mediators, and outcomes. Social determinants of equity, such as laws/policies, economic systems, and structural racism, affect the inequitable access to environmental and neighborhood exposures, in addition to health care access. Although the incidence disparity remains problematic, various studies have demonstrated parity in outcomes when social and health factors, such as access to equitable care, are normalized. Few studies have tested interventions to reduce inequities in prostate cancer among Black men.
Conclusions
Worldwide, men of African ancestry demonstrate worse outcomes in prostate cancer, a phenomenon driven largely by social factors that inform biologic, environmental, and health care risks. A conceptual model was presented that organizes the many factors that influence prostate cancer incidence and mortality. Within that framework, we must understand the current state of inequities in clinical prostate cancer practice, the optimal state of what equitable practice would be, and how achieving equity in prostate cancer care balances costs, benefits, and harms. More robust characterization of the sources of prostate cancer inequities should inform testing of ambitious and innovative interventions as we work toward equity in care and outcomes.
Patient summary
Men of African ancestry demonstrate the highest rates of prostate cancer mortality, which may be reduced through social interventions. We present a framework for formalizing the identification of the drivers of prostate cancer inequities to facilitate the development of interventions and trials to eradicate them
Stochastic Bundle Adjustment for Efficient and Scalable 3D Reconstruction
Current bundle adjustment solvers such as the Levenberg-Marquardt (LM)
algorithm are limited by the bottleneck in solving the Reduced Camera System
(RCS) whose dimension is proportional to the camera number. When the problem is
scaled up, this step is neither efficient in computation nor manageable for a
single compute node. In this work, we propose a stochastic bundle adjustment
algorithm which seeks to decompose the RCS approximately inside the LM
iterations to improve the efficiency and scalability. It first reformulates the
quadratic programming problem of an LM iteration based on the clustering of the
visibility graph by introducing the equality constraints across clusters. Then,
we propose to relax it into a chance constrained problem and solve it through
sampled convex program. The relaxation is intended to eliminate the
interdependence between clusters embodied by the constraints, so that a large
RCS can be decomposed into independent linear sub-problems. Numerical
experiments on unordered Internet image sets and sequential SLAM image sets, as
well as distributed experiments on large-scale datasets, have demonstrated the
high efficiency and scalability of the proposed approach. Codes are released at
https://github.com/zlthinker/STBA.Comment: Accepted by ECCV 202
Hydropower plans in eastern and southern Africa increase risk of concurrent climate-related electricity supply disruption
Hydropower comprises a significant and rapidly expanding proportion of electricity production in eastern and southern Africa. In both regions, hydropower is exposed to high levels of climate variability and regional climate linkages are strong, yet an understanding of spatial interdependences is lacking. Here we consider river basin configuration and define regions of coherent rainfall variability using cluster analysis to illustrate exposure to the risk of hydropower supply disruption of current (2015) and planned (2030) hydropower sites. Assuming completion of the dams planned, hydropower will become increasingly concentrated in the Nile (from 62% to 82% of total regional capacity) and Zambezi (from 73% to 85%) basins. By 2030, 70% and 59% of total hydropower capacity will be located in one cluster of rainfall variability in eastern and southern Africa, respectively, increasing the risk of concurrent climate-related electricity supply disruption in each region. Linking of nascent regional electricity sharing mechanisms could mitigate intraregional risk, although these mechanisms face considerable political and infrastructural challenges
Extrusion of Endodontic Filling Materials: Medico-Legal Aspects. Two Cases
The Authors describe two cases of alleged malpractice due to overfilling. The aim of this article is to underline some medico-legal aspects regarding the quantity of extruded material which may be considered acceptable and the consequent damage to the patient
Dimer Models and Integrable Systems
We explore various aspects of the correspondence between dimer models and
integrable systems recently introduced by Goncharov and Kenyon. Dimer models
give rise to relativistic integrable systems that match those arising from 5d
N=1 gauge theories studied by Nekrasov. We apply the correspondence to dimer
models associated to the Y^{p,0} geometries, showing that they give rise to the
relativistic generalization of the periodic Toda chain originally studied by
Ruijsenaars. The correspondence reduces the calculation of all conserved
charges to a straightforward combinatorial problem of enumerating
non-intersecting paths in the dimer model. We show how the usual periodic Toda
chain emerges in the non-relativistic limit and how the Lax operator
corresponds to the Kasteleyn matrix of the dimer model. We discuss how the
dimer models for general Y^{p,q} manifolds give rise to other relativistic
integrable systems, generalizing the periodic Toda chain and construct the
integrable systems for general Y^{p,p} explicitly. The impurities introduced in
the construction of Y^{p,q} quivers are identified with impurities in twisted
sl(2) XXZ spin chains. Finally we discuss how the physical concept of higgsing
a dimer model provides an efficient method for producing new integrable systems
starting from known ones. We illustrate this idea by constructing the
integrable systems for higgsings of Y^{4,0}.Comment: 29 pages, 16 figures. v2: typos fixe
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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