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maximum likelihood

Ashish P Wasnik, Mathew S Davenport, Ravi K Kaza, William J Weadock, Aaron Udager, Nahid Keshavarzi, Bin Nan, Katherine E Maturen
OBJECTIVE: To determine the diagnostic accuracy of multi-detector CT (MDCT) for differentiating gallbladder cancer from acute and xanthogranulomatous cholecystitis using previously described imaging features. METHODS: In this IRB approved HIPAA-compliant retrospective cohort study, contrast-enhanced MDCT of histologically confirmed acute cholecystitis (n = 17), xanthogranulomatous cholecystitis (n = 25), and gallbladder cancer (n = 18) were reviewed independently by three abdominal radiologists blinded to outcome...
April 14, 2018: Clinical Imaging
Isabel Larridon, Kenneth Bauters, Ilias Semmouri, Jan-Adriaan Viljoen, Christina J Prychid, A Muthama Muasya, Jeremy J Bruhl, Karen L Wilson, Bruno Senterre, Paul Goetghebeur
We investigated the monophyly of Costularia (25 species), a genus of tribe Schoeneae (Cyperaceae) that illustrates a remarkable distribution pattern from southeastern Africa, over Madagascar, the Mascarenes and Seychelles, to Malesia and New Caledonia. A further species, Tetraria borneensis, has been suggested to belong to Costularia. Relationships and divergence times were inferred using an existing four marker phylogeny of Cyperaceae tribe Schoeneae expanded with newly generated sequence data mainly for Costularia s...
April 18, 2018: Molecular Phylogenetics and Evolution
Ilufredo Y Tantoy, Bruce A Cooper, Anand Dhruva, Janine Cataldo, Steven M Paul, Yvette P Conley, Marilyn Hammer, Kord M Kober, Jon D Levine, Christine Miaskowski
PURPOSE: Findings regarding changes in the quality of life (QOL) of patients with gastrointestinal cancers (GI) undergoing chemotherapy (CTX) are inconclusive. Purpose was to evaluate for changes in QOL scores of patients with GI cancers over two cycles of CTX. METHODS: Patients (n = 397) completed disease-specific [i.e., Quality of Life-Scale-Patient Version (QOL-PV)] and generic [12-item Medical Outcomes Study Short Form Survey (SF-12)] measures of QOL a total of six times over two cycles of CTX...
April 21, 2018: Quality of Life Research
Pablo A Salcedo, Jacob B Lindheimer, Jacquelyn C Klein-Adams, Anays M Sotolongo, Michael J Falvo
OBJECTIVE: To quantify the effect of exercise training on indices of pulmonary function in adults with chronic lung disease using meta-analytic techniques. Whole body exercise training is well-known to confer favorable adaptations to multiple organ systems; however, exercise-induced adaptations to the respiratory system are assumed to be limited, if present at all, but have not been systematically reviewed. DATA SOURCES: Eligible trials were identified using a systematic search of Medline, Web of Science, Physiotherapy Evidence Database (PEDro) and GoogleScholar databases...
April 17, 2018: Archives of Physical Medicine and Rehabilitation
A Vargas, N Cornejo, A Camp
The Universitat Politecnica de Catalunya (UPC) and the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) have evaluated methods based on stripping, conversion coefficients and Maximum Likelihood Estimation using Expectation Maximization (ML-EM) in calculating the H*(10) rates from photon pulse-height spectra acquired with a spectrometric LaBr3 (Ce)(1.5″ × 1.5″) detector. There is a good agreement between results of the different H*(10) rate calculation methods using the spectra measured at the UPC secondary standard calibration laboratory in Barcelona...
March 31, 2018: Applied Radiation and Isotopes
Garrett Greene, Richard W Costello, Breda Cushen, Imran Sulaiman, Elaine Mac Hale, Ronan M Conroy, Frank Doyle
OBJECTIVE: We derive a novel model-based metric for effective adherence to medication, and validate it using data from the INhaler Compliance Assessment device (INCATM). This technique employs dose timing data to estimate the threshold drug concentration needed to maintain optimal health. METHODS: The parameters of the model are optimised against patient outcome data using maximum likelihood methods. The model is fitted and validated by secondary analysis of two independent datasets from two remote-monitoring studies of adherence, conducted through clinical research centres of 5 Irish hospitals...
2018: PloS One
Mingzhi Luo, Xiang Chen, Shuai Cao, Xu Zhang
Time difference of arrival (TDoA) measurement is a promising approach for target localization based on a set of nodes with known positions, with high accuracy and low complexity. Common localization algorithms include the maximum-likelihood, non-linear least-squares and weighted least-squares methods. These methods have shortcomings such as high computational complexity, requiring an initial guess position, or having difficulty in finding the optimal solution. From the point of view of geometrical analysis, this study proposes two new shrinking-circle methods (SC-1 and SC-2) to solve the TDoA-based localization problem in a two-dimensional (2-D) space...
April 20, 2018: Sensors
Hans-Peter Piepho, Laurence V Madden, James Roger, Roger Payne, Emlyn R Williams
Network meta-analysis can be implemented by using arm-based or contrast-based models. Here we focus on arm-based models and fit them using generalized linear mixed model procedures. Full maximum likelihood (ML) estimation leads to biased trial-by-treatment interaction variance estimates for heterogeneity. Thus, our objective is to investigate alternative approaches to variance estimation that reduce bias compared with full ML. Specifically, we use penalized quasi-likelihood/pseudo-likelihood and hierarchical (h) likelihood approaches...
April 19, 2018: Pharmaceutical Statistics
Kate C Mellor, Anne Meyer, Doaa A Elkholly, Guillaume Fournié, Pham T Long, Ken Inui, Pawin Padungtod, Marius Gilbert, Scott H Newman, Timothée Vergne, Dirk U Pfeiffer, Kim B Stevens
Highly pathogenic avian influenza (HPAI) H5N1 virus has been circulating in Vietnam since 2003, whilst outbreaks of HPAI H5N6 virus are more recent, having only been reported since 2014. Although the spatial distribution of H5N1 outbreaks and risk factors for virus occurrence has been extensively studied, there have been no comparative studies for H5N6. Data collected through active surveillance of Vietnamese live bird markets (LBMs) between 2011 and 2015 were used to explore and compare the spatiotemporal distributions of H5N1- and H5N6-positive LBMs...
2018: Frontiers in Veterinary Science
Feng Cui, Yanyan Yu, Fangyin Bao, Song Wang, Ming Song Xiao
The oriental river prawn (Macrobrachium nipponense) is an economically and nutritionally important species of decapod crustaceans in China. Genetic structure and demographic history of Macrobrachium nipponense were examined using sequence data from portions of the mitochondrial DNA cytochrome oxidase subunit I (COI) gene. Samples of 191 individuals were collected from 10 localities in the upper to middle reaches of the Huaihe River. Variability was detected at a total of 42 nucleotide sites along 684 bp length of homologous sequence (6...
April 19, 2018: Mitochondrial DNA. Part A. DNA Mapping, Sequencing, and Analysis
Alberto Laffranchi, Calogero Cicero, Manuela Lualdi, Chiara M Ciniselli, Giuseppina Calareso, Stefano Canestrini, Francesca G Greco, Enrico Alberioli, Claudia Cavatorta, Alessandro Guarise, Emanuele Pignoli, Maddalena Plebani, Davide Scaramuzza, Claudio Siciliano, Paolo Verderio, Alfonso Marchianò
AIM: To evaluate the effects of display pixel pitch and maximum luminance on intra- and inter-observer reproducibility and observer performance when evaluating chest lesions and bone fractures. MATERIALS AND METHODS: This was a multi-institutional study for a retrospective interpretation of selected digital radiography images. Overall, 82 images were selected by senior radiologists, including 50 cases of chest lesions and 32 cases of bone fractures. These images were displayed at two pixel pitches (0...
April 18, 2018: La Radiologia Medica
Xu Chen, Ralf Kuja-Halkola, Zheng Chang, Robert Karlsson, Sara Hägg, Per Svensson, Nancy L Pedersen, Patrik K E Magnusson
BACKGROUND: The variation and covariation for many cardiometabolic traits have been decomposed into genetic and environmental fractions, by using twin or single-nucleotide polymorphism (SNP) models. However, differences in population, age, sex, and other factors hamper the comparison between twin- and SNP-based estimates. METHODS AND RESULTS: Twenty-four cardiometabolic traits and 700,000 genotyped SNPs were available in the study base of 10 682 twins from TwinGene cohort...
April 18, 2018: Journal of the American Heart Association
Boni Amin Laskar, Vikas Kumar, Shantanu Kundu, Achom Darshan, Kaomud Tyagi, Kailash Chandra
DNA barcoding technique has been gaining importance in biodiversity research for its easy and rapid ability of delineating organisms' partial DNA sequences into molecular operational taxonomic units (MOTUs), and identification based on referral sequences from expert identified species. We generated mtCOI barcode sequences from morphologically identified fishes from River Diphlu in northeast India. A portion of this river falls within an important rhinoceros and tiger conservation site, the Kaziranga National Park...
April 18, 2018: Mitochondrial DNA. Part A. DNA Mapping, Sequencing, and Analysis
Péter Hudomiet, Michael D Hurd, Susann Rohwedder
Objectives: Age- and sex-specific rates of dementia are estimated in the U.S. population aged 65 or older in 2000 and 2012 using a large nationally representative dataset, the Health and Retirement Study (HRS), and accounting for mortality selection and specificities of the interview protocol. Method: A latent cognitive ability model is estimated by maximum simulated likelihood. Prevalence of dementia is identified using HRS cognition measures and the Aging, Demographics and Memory Study (ADAMS), a subset of the HRS (n = 856) with clinical assessment for dementia...
April 16, 2018: Journals of Gerontology. Series B, Psychological Sciences and Social Sciences
Sezayi Ozubek, Munir Aktas
This study reports a novel species of Babesia in unfed Rhipicephalus sanguineus sensu lato and its phylogenetic relationship to other species. One-hundred and forty DNA samples extracted from tick pools comprising 5,403 unfed R. sanguineus s.l. ticks were screened for Babesia. Overall Babesia infection was detected in female, male, and nymph pools with an infection rate maximum likelihood estimate (MLE) of 1.98 (CI 0.65-4.74), 0.50 (CI 0.03-2.40), and 0.07 (CI 0.01-0.21), respectively. Three adult female tick pools (MLE 1...
April 16, 2018: Journal of Medical Entomology
Tanja M Schuster, Sabrina D Setaro, Josquin F G Tibbits, Erin L Batty, Rachael M Fowler, Todd G B McLay, Stephen Wilcox, Peter K Ades, Michael J Bayly
Previous molecular phylogenetic analyses have resolved the Australian bloodwood eucalypt genus Corymbia (~100 species) as either monophyletic or paraphyletic with respect to Angophora (9-10 species). Here we assess relationships of Corymbia and Angophora using a large dataset of chloroplast DNA sequences (121,016 base pairs; from 90 accessions representing 55 Corymbia and 8 Angophora species, plus 33 accessions of related genera), skimmed from high throughput sequencing of genomic DNA, and compare results with new analyses of nuclear ITS sequences (119 accessions) from previous studies...
2018: PloS One
Seyedehnafiseh Mirniaharikandehei, Alan B Hollingsworth, Bhavika Patel, Morteza Heidari, Hong Liu, Bin Zheng
This study aims to investigate the feasibility of identifying a new quantitative imaging marker based on false-positives generated by computer-aided detection (CAD) scheme to help predict short-term breast cancer risk. An image dataset including four view mammograms acquired from 1,044 women was retrospectively assembled. All mammograms were originally interpreted as negative by radiologists. In the next subsequent mammography screening, 402 women were diagnosed with breast cancer and 642 remained negative...
April 18, 2018: Physics in Medicine and Biology
Minjung Lee, Eric J Feuer, Jason P Fine
Regression methodology has been well developed for competing risks data with continuous event times, both for the cause-specific hazard and cumulative incidence functions. However, in many applications, including those from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute, the event times may be observed discretely. Naive application of continuous time regression methods to such data is not appropriate. We propose maximum likelihood inferences for estimation of model parameters for the discrete time cause-specific hazard functions, develop predictions for the associated cumulative incidence functions, and derive consistent variance estimators for the predicted cumulative incidence functions...
April 17, 2018: Biometrics
Michel Defrise, Ahmadreza Rezaei, Johan Nuyts
This paper presents new data driven methods for the time of flight (TOF) calibration of positron emission tomography (PET) scanners. 
 These methods are derived from the consistency condition for TOF PET, they can be applied to data measured with an arbitrary tracer distribution and are numerically efficient because they do not require a preliminary image reconstruction from the non-TOF data. 
 Two-dimensional simulations are presented for one of the methods, which only involves the two first moments of the data with respect to the TOF variable...
April 17, 2018: Physics in Medicine and Biology
Andrea Di Cesare, Pedro J Cabello-Yeves, Nathan A M Chrismas, Patricia Sánchez-Baracaldo, Michaela M Salcher, Cristiana Callieri
BACKGROUND: Many cyanobacteria are capable of fixing atmospheric nitrogen, playing a crucial role in biogeochemical cycling. Little is known about freshwater unicellular cyanobacteria Synechococcus spp. at the genomic level, despite being recognised of considerable ecological importance in aquatic ecosystems. So far, it has not been shown whether these unicellular picocyanobacteria have the potential for nitrogen fixation. Here, we present the draft-genome of the new pink-pigmented Synechococcus-like strain Vulcanococcus limneticus...
April 16, 2018: BMC Genomics
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