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Kernel density

David Barbic, Brian Klinkenberg, Brian Grunau, Jim Christenson
OBJECTIVE: No prior work exists examining the relation between the geographic distribution of out-of-hospital cardiac arrest (OHCA) in the city of Vancouver and surrounding areas that may exhibit a clustering of cases. The primary objective of this study was to describe the distribution of OHCA within the Vancouver Coastal Health region using a geographic information system (GIS) analysis and appropriate statistical analyses. METHODS: This study was a post-hoc GIS-based analysis of OHCA patients in the city of Vancouver and surrounding areas, using data collected by the Resuscitation Outcomes Consortium between September 2007 and December 2011...
October 17, 2016: CJEM
Brandon Miles, Ismail Ben Ayed, Seyed-Parsa Hojjat, Michael H Wang, Shuo Li, Aaron Fenster, Gregory J Garvin
This study investigates a fast integral-kernel algorithm for classifying (labeling) the vertebra and disc structures in axial magnetic resonance images (MRI). The method is based on a hierarchy of feature levels, where pixel classifications via non-linear probability product kernels (PPKs) are followed by classifications of 2D slices, individual 3D structures and groups of 3D structures. The algorithm further embeds geometric priors based on anatomical measurements of the spine. Our classifier requires evaluations of computationally expensive integrals at each pixel, and direct evaluations of such integrals would be prohibitively time consuming...
October 1, 2016: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
Jannis Erhard, Patrick Bleiziffer, Andreas Görling
A power series approximation for the correlation kernel of time-dependent density-functional theory is presented. Using this approximation in the adiabatic-connection fluctuation-dissipation (ACFD) theorem leads to a new family of Kohn-Sham methods. The new methods yield reaction energies and barriers of unprecedented accuracy and enable a treatment of static (strong) correlation with an accuracy of high-level multireference configuration interaction methods but are single-reference methods allowing for a black-box-like handling of static correlation...
September 30, 2016: Physical Review Letters
Lars Qviller, Hildegunn Viljugrein, Leif Egil Loe, Erling L Meisingset, Atle Mysterud
BACKGROUND: Many wingless ectoparasites have a limited capacity for active movement and are therefore primarily dependent on hitchhiking on their hosts for transportation. The distribution of the tick Ixodes ricinus is expected to depend mainly on transportation by hosts and tick subsequent survival in areas where they drop off. In Europe, the most important hosts of adult female I. ricinus are cervids. The extensive space use of large hosts provides a much larger dispersal potential for I...
October 13, 2016: Parasites & Vectors
Alba Cebrecos, Julia Díez, Pedro Gullón, Usama Bilal, Manuel Franco, Francisco Escobar
BACKGROUND: Healthier urban environments influence the distribution of cardiovascular risk factors. Our aim was to design and implement a multicomponent method based on Geographic Information Systems to characterize and evaluate environmental correlates of obesity: the food and the physical activity urban environments. METHODS: Study location comprised a socio-demographically average urban area of 12 contiguous census sections (≈16,000 residents), in Madrid, Spain...
October 4, 2016: International Journal of Health Geographics
Katharina Keller, Michal Zalibera, Mian Qi, Vanessa Koch, Julia Wegner, Henrik Hintz, Adelheid Godt, Gunnar Jeschke, Anton Savitsky, Maxim Yulikov
The four Mn(ii) complexes Mn-DOTA, Mn-TAHA, Mn-PyMTA, and Mn-NO3Py were characterized by electron paramagnetic resonance (EPR), electron-nuclear double resonance (ENDOR), and relaxation measurements, to predict their relative performance in the EPR pulse dipolar spectroscopy (PDS) experiments. High spin density localization on the metal ions was proven by ENDOR on (1)H, D, (14)N, and (55)Mn nuclei. The transverse relaxation of the Mn(ii) complexes appears to be slow enough for PDS-based spin-spin distance determination...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Benjamin W Chrisinger, Anne V Grossestreuer, Meredith C Laguna, Heather M Griffis, Charles C Branas, Douglas J Wiebe, Raina M Merchant
AIM: Approximately 424,000 out-of-hospital cardiac arrests (OHCA) occur in the US annually. As automated external defibrillators (AED) are an important part of the community response to OHCA, we investigated how well the spatial demand (likelihood of OHCA) was met by the spatial supply (AEDs) in a dense urban environment. METHODS: Using geographic information system (GIS) software, we applied kernel density and optimized hot spot procedures with two differently-sized radii to model OHCA incidence rates from existing studies, providing an estimate of OHCA likelihood at a given location...
October 1, 2016: Resuscitation
Silky Jain, Sandeep Jain, Gauri Kapoor, Anju Virmani, Ram Bajpai
BACKGROUND: Acute lymphoblastic leukemia (ALL) and its treatment are often implicated in adversely affecting bone health. Conflicting reports in the literature and a paucity of studies from the developing world prompted us to study bone mineral density (BMD) in childhood ALL survivors. METHODS: BMD lumbar spine (LS) and whole body (WB) were evaluated, using dual energy x-ray absorptiometry in 65 pediatric ALL survivors who had been off-therapy for at least 2 years...
September 26, 2016: Pediatric Blood & Cancer
Huihui Gao, Feifei Liu, Qunxiong Zhu
Different alarm thresholds could generate different alarm data, resulting in different correlations. A new multivariate alarm thresholds optimization methodology based on the correlation consistency between process data and alarm data is proposed in this paper. The interpretative structural modeling is adopted to select the key variables. For the key variables, the correlation coefficients of process data are calculated by the Pearson correlation analysis, while the correlation coefficients of alarm data are calculated by kernel density estimation...
September 22, 2016: ISA Transactions
Maoqi Chen, Ales Holobar, Xu Zhang, Ping Zhou
Decomposition of electromyograms (EMG) is a key approach to investigating motor unit plasticity. Various signal processing techniques have been developed for high density surface EMG decomposition, among which the convolution kernel compensation (CKC) has achieved high decomposition yield with extensive validation. Very recently, a progressive FastICA peel-off (PFP) framework has also been developed for high density surface EMG decomposition. In this study, the CKC and PFP methods were independently applied to decompose the same sets of high density surface EMG signals...
2016: Neural Plasticity
Anant Dixit, János G Ángyán, Dario Rocca
A new formalism was recently proposed to improve random phase approximation (RPA) correlation energies by including approximate exchange effects [B. Mussard et al., J. Chem. Theory Comput. 12, 2191 (2016)]. Within this framework, by keeping only the electron-hole contributions to the exchange kernel, two approximations can be obtained: An adiabatic connection analog of the second order screened exchange (AC-SOSEX) and an approximate electron-hole time-dependent Hartree-Fock (eh-TDHF). Here we show how this formalism is suitable for an efficient implementation within the plane-wave basis set...
September 14, 2016: Journal of Chemical Physics
Hong Zhou, Shihang Liu, Yujiao Liu, Yaxi Liu, Jing You, Mei Deng, Jian Ma, Guangdeng Chen, Yuming Wei, Chunji Liu, Youliang Zheng
BACKGROUND: Kernel length is an important target trait in barley (Hordeum vulgare L.) breeding programs. However, the number of known quantitative trait loci (QTLs) controlling kernel length is limited. In the present study, we aimed to identify major QTLs for kernel length, as well as putative candidate genes that might influence kernel length in wild barley. RESULTS: A recombinant inbred line (RIL) population derived from the barley cultivar Baudin (H. vulgare ssp...
2016: BMC Genetics
S Thompson, T Avent, L S Doughty
The Southern white rhinoceros (Ceratotherium simum) is a threatened species, central to the tourism appeal of private game reserves in South Africa. Privately owned reserves in South Africa tend to be smaller than government run reserves such as Kruger National Park. Because of their relatively small size and the often heterogeneous nature of the landscape private game reserve managers benefit from detailed knowledge of white rhinoceros terrain selection preferences, which can be assessed from their ranging behaviours...
2016: PloS One
Jun Wang, Kevin Kai Xu
LiDAR scanning has become a prevalent technique for digitalizing large-scale outdoor scenes. However, the raw LiDAR data often contain imperfections, e.g., missing large regions, anisotropy of sampling density, and contamination of noise and outliers, which are the major obstacles that hinder its more ambitious and higher level applications in digital city modeling. Observing that 3D urban scenes can be locally described with several low dimensional subspaces, we propose to locally classify the neighborhoods of the scans to model the substructures of the scenes...
August 31, 2016: IEEE Transactions on Visualization and Computer Graphics
Zhi-An Deng, Guofeng Wang, Danyang Qin, Zhenyu Na, Yang Cui, Juan Chen
To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy...
2016: Sensors
Jessie Y Huang, David S Followill, Rebecca M Howell, Xinming Liu, Dragan Mirkovic, Francesco C Stingo, Stephen F Kry
PURPOSE: Dose calculation errors near metal implants are caused by limitations of the dose calculation algorithm in modeling tissue/metal interface effects as well as density assignment errors caused by imaging artifacts. The purpose of this study was to investigate two strategies for reducing dose calculation errors near metal implants: implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) dose calculation method and use of metal artifact reduction methods for computed tomography (CT) imaging...
September 2016: Medical Physics
Mirna de Abreu E Silva, Cláudia Di Lorenzo Oliveira, Rafael Gonçalves Teixeira Neto, Paulo Augusto Camargos
BACKGROUND: Tuberculosis (TB) remains a major public health problem in many developing countries. Exploratory spatial analysis is a powerful instrument in spatial health research by virtue of its capacity to map disease distribution and associated risk factors at the population level. The aim of the present study was to describe the epidemiologic characteristics and spatial distribution of new cases of TB reported during the period 2002-2012 in Divinopolis, a midsized city located in the state of Minas Gerais, southeastern Brazil...
2016: BMC Public Health
Homayoun Harirforoush, Lynda Bellalite
This paper proposes a two-step integrated method for identifying traffic accident (TA) hotspots on a roadway network. The first step includes a spatial analysis method called network kernel density estimation (KDE). The second step is a network screening method using the critical crash rate, which it described in the Highway Safety Manual (HSM). The method was examined by using three years of TAs (2011-2013) in Sherbrooke, Canada. The network KDE uses TAs to graphically display sites with a high crash density...
August 24, 2016: Accident; Analysis and Prevention
Sarah Neal, Corrine Ruktanonchai, Venkatraman Chandra-Mouli, Zoë Matthews, Andrew J Tatem
BACKGROUND: Early adolescent pregnancy presents a major barrier to the health and wellbeing of young women and their children. Previous studies suggest geographic heterogeneity in adolescent births, with clear "hot spots" experiencing very high prevalence of teenage pregnancy. As the reduction of adolescent pregnancy is a priority in many countries, further detailed information of the geographical areas where they most commonly occur is of value to national and district level policy makers...
2016: Reproductive Health
Jianhua Ni, Tianlu Qian, Changbai Xi, Yikang Rui, Jiechen Wang
The spatial distribution of urban service facilities is largely constrained by the road network. In this study, network point pattern analysis and correlation analysis were used to analyze the relationship between road network and healthcare facility distribution. The weighted network kernel density estimation method proposed in this study identifies significant differences between the outside and inside areas of the Ming city wall. The results of network K-function analysis show that private hospitals are more evenly distributed than public hospitals, and pharmacy stores tend to cluster around hospitals along the road network...
2016: International Journal of Environmental Research and Public Health
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