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https://www.readbyqxmd.com/read/28445432/multispectral-lidar-data-for-land-cover-classification-of-urban-areas
#1
Salem Morsy, Ahmed Shaker, Ahmed El-Rabbany
Airborne Light Detection And Ranging (LiDAR) systems usually operate at a monochromatic wavelength measuring the range and the strength of the reflected energy (intensity) from objects. Recently, multispectral LiDAR sensors, which acquire data at different wavelengths, have emerged. This allows for recording of a diversity of spectral reflectance from objects. In this context, we aim to investigate the use of multispectral LiDAR data in land cover classification using two different techniques. The first is image-based classification, where intensity and height images are created from LiDAR points and then a maximum likelihood classifier is applied...
April 26, 2017: Sensors
https://www.readbyqxmd.com/read/28444811/three-year-income-trends-in-korean-adults-commencing-hemodialysis-a-prospective-cohort
#2
Myoung-Hee Kim, Yong Chul Kim, Jung Pyo Lee, Ho Kim, Dong Ki Kim, Dong-Ryeol Ryu, Seung Seok Han, Jeonghwan Lee, Yong-Lim Kim, Shin-Wook Kang, Jang-Hee Cho, Yon Su Kim
AIM: This study aimed to explore the trends in individual income and to estimate the change in average monthly income for patients undergoing hemodialysis therapy. METHODS: The main data source was the Clinical Research Center (CRC) for End-Stage Renal Disease in Korea. In addition to the cohort data, a survey was conducted to capture personal income for 3 years. To estimate the change in monthly income over time using repeated measures, a random coefficient model using penalized quasi-likelihood methods based on restricted or residual maximum likelihood estimation was employed...
April 25, 2017: Nephrology
https://www.readbyqxmd.com/read/28441977/detecting-clusters-in-atom-probe-data-with-gaussian-mixture-models
#3
Jennifer Zelenty, Andrew Dahl, Jonathan Hyde, George D W Smith, Michael P Moody
Accurately identifying and extracting clusters from atom probe tomography (APT) reconstructions is extremely challenging, yet critical to many applications. Currently, the most prevalent approach to detect clusters is the maximum separation method, a heuristic that relies heavily upon parameters manually chosen by the user. In this work, a new clustering algorithm, Gaussian mixture model Expectation Maximization Algorithm (GEMA), was developed. GEMA utilizes a Gaussian mixture model to probabilistically distinguish clusters from random fluctuations in the matrix...
April 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28441969/molecular-identification-of-plasmodium-spp-and-blood-meal-sources-of-anophelines-in-environmental-reserves-on-s%C3%A3-o-lu%C3%A3-s-island-state-of-maranh%C3%A3-o-brazil
#4
Mayra Araguaia Pereira Figueiredo, Silvia Maria Di Santi, Wilson Gómez Manrique, Luiz Ricardo Gonçalves, Marcos Rogério André, Rosangela Zacarias Machado
BACKGROUND: Considering the diversity of feeding habits that females of some species of anophelines present, it is important to understand which vertebrates are part of blood food sources and how important is the role of each in the ecoepidemiology of malaria. There are many vector species for Plasmodium spp. in the State of Maranhão, Brazil. In São Luís Island, Anopheles aquasalis is the main vector for human malaria; this species is abundant in areas with primates that are positive for Plasmodium...
April 26, 2017: Parasites & Vectors
https://www.readbyqxmd.com/read/28441139/empirical-likelihood-in-nonignorable-covariate-missing-data-problems
#5
Yanmei Xie, Biao Zhang
Missing covariate data occurs often in regression analysis, which frequently arises in the health and social sciences as well as in survey sampling. We study methods for the analysis of a nonignorable covariate-missing data problem in an assumed conditional mean function when some covariates are completely observed but other covariates are missing for some subjects. We adopt the semiparametric perspective of Bartlett et al. (Improving upon the efficiency of complete case analysis when covariates are MNAR. Biostatistics 2014;15:719-30) on regression analyses with nonignorable missing covariates, in which they have introduced the use of two working models, the working probability model of missingness and the working conditional score model...
April 20, 2017: International Journal of Biostatistics
https://www.readbyqxmd.com/read/28440467/structural-and-evolutionary-divergence-of-aquaporins-in-parasites-review
#6
Zi-Xin Ni, Jian-Min Cui, Nian-Zhang Zhang, Bao-Quan Fu
Aquaporins are ubiquitous proteins that belong to the major intrinsic protein family. Previous studies have indicated that aquaporins are involved in multiple physiological processes in parasites, such as nutrient absorption and end product efflux, and thus, would be promising pharmacological agents in the fight against parasite infection. In the present paper, the authors analyzed the evolutionary relationship of parasitic aquaporins by re‑constructing of a phylogenic tree using neighbor‑joining and maximum likelihood methods...
April 25, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28439776/preoperative-grading-of-supratentorial-nonenhancing-gliomas-by-high-b-value-diffusion-weighted-3%C3%A2-t-magnetic-resonance-imaging
#7
Haiwei Han, Chengkun Han, Xiurong Wu, Shan Zhong, Xiongjie Zhuang, Guowei Tan, Hua Wu
The purpose of this study was to determine the difference in discrimination between high- and low-grade supratentorial nonenhancing gliomas (HGGs and LGGs, respectively) when using apparent diffusion coefficient (ADC) values with high or standard b-value. Thirty-nine patients underwent conventional magnetic resonance imaging and diffusion-weighted imaging (DWI) with standard and high b-values (b = 1000 and 3000 s/mm(2), respectively). Minimum, maximum, and mean ADC values (ADCMIN, ADCMAX, and ADCMEAN, respectively) were measured from ADC maps with both b-values...
April 24, 2017: Journal of Neuro-oncology
https://www.readbyqxmd.com/read/28437950/maximum-likelihood-sequence-estimation-for-optical-complex-direct-modulation
#8
Di Che, Feng Yuan, William Shieh
Semiconductor lasers are versatile optical transmitters in nature. Through the direct modulation (DM), the intensity modulation is realized by the linear mapping between the injection current and the light power, while various angle modulations are enabled by the frequency chirp. Limited by the direct detection, DM lasers used to be exploited only as 1-D (intensity or angle) transmitters by suppressing or simply ignoring the other modulation. Nevertheless, through the digital coherent detection, simultaneous intensity and angle modulations (namely, 2-D complex DM, CDM) can be realized by a single laser diode...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437735/detective-quantum-efficiency-dqe-in-pet-scanners-a-simulation-study
#9
George E Karpetas, Christos M Michail, George P Fountos, Nektarios I Kalyvas, Ioannis G Valais, Ioannis S Kandarakis, George S Panayiotakis
The aim of the present study is to introduce the detective quantum efficiency (DQE) for the image quality assessment of positron emission tomography (PET) scanners. For this purpose, a thin layer chromatography (TLC) plane source was simulated using a previously validated, scanner and source geometry, Monte Carlo (MC) model. The model was developed with the Geant4 application for tomographic emission (GATE) MC package and reconstructed images obtained with the software for tomographic image reconstruction (STIR), with cluster computing...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28437561/semiparametric-probit-models-with-univariate-and-bivariate-current-status-data
#10
Hao Liu, Jing Qin
Multivariate current-status data are frequently encountered in biomedical and public health studies. Semiparametric regression models have been extensively studied for univariate current-status data, but most existing estimation procedures are computationally intensive, involving either penalization or smoothing techniques. It becomes more challenging for the analysis of multivariate current-status data. In this article, we study the maximum likelihood estimations for univariate and bivariate current-status data under the semiparametric probit regression models...
April 24, 2017: Biometrics
https://www.readbyqxmd.com/read/28436844/probabilistic-elastic-part-model-a-pose-invariant-representation-for-real-world-face-verification
#11
Haoxiang Li, Gang Hua
Pose variation remains to be a major challenge for real-world face recognition. We approach this problem through a probabilistic elastic part model. We extract local descriptors (e.g., LBP or SIFT) from densely sampled multi-scale image patches. By augmenting each descriptor with its location, a Gaussian mixture model (GMM) is trained to capture the spatial-appearance distribution of the face parts of all face images in the training corpus, namely the probabilistic elastic part (PEP) model. Each mixture component of the GMM is confined to be a spherical Gaussian to balance the influence of the appearance and the location terms, which naturally defines a part...
April 18, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/28436046/simulation-based-adjustment-after-exploratory-biomarker-subgroup-selection-in-phase-ii
#12
Heiko Götte, Marietta Kirchner, Martin Oliver Sailer, Meinhard Kieser
As part of the evaluation of phase II trials, it is common practice to perform exploratory subgroup analyses with the aim of identifying patient populations with a beneficial treatment effect. When investigating targeted therapies, these subgroups are typically defined by biomarkers. Promising results may lead to the decision to select the respective subgroup as the target population for a subsequent phase III trial. However, a selection based on a large observed treatment effect may potentially induce an upwards-bias leading to over-optimistic expectations on the success probability of the phase III trial...
April 24, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28435181/orthogonality-of-the-mean-and-error-distribution-in-generalized-linear-models
#13
Alan Huang, Paul J Rathouz
We show that the mean-model parameter is always orthogonal to the error distribution in generalized linear models. Thus, the maximum likelihood estimator of the mean-model parameter will be asymptotically efficient regardless of whether the error distribution is known completely, known up to a finite vector of parameters, or left completely unspecified, in which case the likelihood is taken to be an appropriate semiparametric likelihood. Moreover, the maximum likelihood estimator of the mean-model parameter will be asymptotically independent of the maximum likelihood estimator of the error distribution...
2017: Communications in Statistics: Theory and Methods
https://www.readbyqxmd.com/read/28435014/maximum-likelihood-estimates-of-pairwise-rearrangement-distances
#14
Stuart Serdoz, Attila Egri-Nagy, Jeremy Sumner, Barbara R Holland, Peter D Jarvis, Mark M Tanaka, Andrew R Francis
Accurate estimation of evolutionary distances between taxa is important for many phylogenetic reconstruction methods. Distances can be estimated using a range of different evolutionary models, from single nucleotide polymorphisms to large-scale genome rearrangements. Corresponding corrections for genome rearrangement distances fall into 3 categories: Empirical computational studies, Bayesian/MCMC approaches, and combinatorial approaches. Here, we introduce a maximum likelihood estimator for the inversion distance between a pair of genomes, using a group-theoretic approach to modelling inversions introduced recently...
April 20, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28434717/relative-genetic-and-environmental-contributions-to-variations-in-human-retinal-electrical-responses-quantified-in-a-twin-study
#15
Taha Bhatti, Ambreen Tariq, Ting Shen, Katie M Williams, Christopher J Hammond, Omar A Mahroo
PURPOSE: To estimate heritability of parameters of human retinal electrophysiology and to explore which parameters change with age. DESIGN: Prospective, classic twin study. PARTICIPANTS: Adult monozygotic and dizygotic twin pairs recruited from the TwinsUK cohort. METHODS: Electroretinogram responses were recorded using conductive fiber electrodes in response to stimuli incorporating standards set by the International Society for the Clinical Electrophysiology of Vision...
April 20, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28433947/maximum-likelihood-estimation-of-cardiac-fiber-bundle-orientation-from-arbitrarily-spaced-diffusion-weighted-images
#16
Andreas Nagler, Cristóbal Bertoglio, Christian T Stoeck, Sebastian Kozerke, Wolfgang A Wall
We propose an estimation scheme for local fiber bundle direction in the left ventricle directly from gray values of arbitrarily spaced cardiac diffusion weighted images (DWI). The approach is based on a parametric and space-dependent mathematical representation of the myocardial fiber bundle orientation and hence the diffusion tensor (DT) for the ventricular geometry. By solving a nonlinear inverse problem derived from a maximum likelihood estimator, the degrees of freedom of the fiber and DT model can be estimated from the measured gray values of the DWIs...
April 4, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28433621/simultaneous-speciation-in-the-european-high-mountain-flowering-plant-genus-facchinia-minuartia-s-l-caryophyllaceae-revealed-by-genotyping-by-sequencing
#17
Markus S Dillenberger, Joachim W Kadereit
Understanding the relative importance of different mechanisms of speciation in a given lineage requires fully resolved interspecific relationships. Using Facchinia, a genus of seven species centred in the European Alps, we explore whether the polytomy found by Sanger sequencing analyses of standard nuclear (ITS) and plastid markers (trnQ-rps16) is a hard or soft polytomy by substantially increasing the amount of DNA sequence data, generated by genotyping-by-sequencing. In comparison to 142 phylogenetically informative sites in the Sanger sequences the GBS sequences yielded 3363 phylogenetically informative sites after exclusion of apparently oversaturated SNPs...
April 19, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/28432484/complete-mitochondrial-genome-sequences-of-korean-native-horse-from-jeju-island-uncovering-the-spatio-temporal-dynamics
#18
Sook Hee Yoon, Jaemin Kim, Donghyun Shin, Seoae Cho, Woori Kwak, Hak-Kyo Lee, Kyoung-Do Park, Heebal Kim
The Korean native horse (Jeju horse) is one of the most important animals in Korean historical, cultural, and economical viewpoints. In the early 1980s, the Jeju horse was close to extinction. The aim of this study is to explore the phylogenomics of Korean native horse focusing on spatio-temporal dynamics. We determined complete mitochondrial genome sequences for the first Korean native (n = 6) and additional Mongolian (n = 2) horses. Those sequences were analyzed together with 143 published ones using Bayesian coalescent approach as well as three different phylogenetic analysis methods, Bayesian inference, maximum likelihood, and neighbor-joining methods...
April 21, 2017: Molecular Biology Reports
https://www.readbyqxmd.com/read/28432210/a-randomised-controlled-trial-of-a-complex-intervention-to-reduce-children-s-exposure-to-secondhand-smoke-in-the-home
#19
Elena Ratschen, Rebecca Thorley, Laura Jones, Magdalena Opazo Breton, Juliette Cook, Ann McNeill, John Britton, Tim Coleman, Sarah Lewis
OBJECTIVES: Exposing children to secondhand tobacco smoke (SHS) causes significant harm and occurs predominantly through smoking by caregivers in the family home. We report a trial of a complex intervention designed to reduce secondhand smoke exposure of children whose primary caregiver feels unable or unwilling to quit smoking. DESIGN: An open-label, parallel, randomised controlled trial. SETTING: Deprived communities in Nottingham City and County, England PARTICIPANTS: Caregivers resident in Nottingham City and County in England who were at least 18 years old, the main caregiver of a child aged under 5 years living in their household, and reported that they were smoking tobacco inside their home...
April 21, 2017: Tobacco Control
https://www.readbyqxmd.com/read/28431171/heritability-of-heart-rate-response-to-arousals-in-twins
#20
Xiaoling Gao, Ali Azarbarzin, Brendan T Keenan, Michele Ostrowski, Frances M Pack, Bethany Staley, Greg Maislin, Allan I Pack, Magdy Younes, Samuel T Kuna
Objectives: To determine if the large and highly reproducible inter-individual differences in arousal intensity and heart rate response to arousal (ΔHR) during non-REM sleep are heritable. Methods: Polysomnograms of 55 monozygotic (14 male and 41 female pairs) and 36 dizygotic (15 male and 21 female pairs) same-sex twin pairs were analyzed. Arousals were scored using the 2012 American Academy of Sleep Medicine criteria. Arousal intensity was scaled (between 0 and 9) using an automatic algorithm based on the change in EEG time and frequency characteristics...
April 18, 2017: Sleep
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