2,834 results match your criteria parsimonious models

Modelling costs of community-based HIV self-testing programmes in Southern Africa at scale: an econometric cost function analysis across five countries.

BMJ Glob Health 2021 Jul;6(Suppl 4)

Department of Global Health and Development, London School of Hygiene & Tropical Medicine, London, UK.

Background: Following success demonstrated with the HIV Self-Testing AfRica Initiative, HIV self-testing (HIVST) is being added to national HIV testing strategies in Southern Africa. An analysis of the costs of scaling up HIVST is needed to inform national plans, but there is a dearth of evidence on methods for forecasting costs at scale from pilot projects. Econometric cost functions (ECFs) apply statistical inference to predict costs; however, we often do not have the luxury of collecting large amounts of location-specific data. Read More

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Using path analysis to test theory of change: a quantitative process evaluation of the MapSan trial.

BMC Public Health 2021 Jul 16;21(1):1411. Epub 2021 Jul 16.

Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK.

Background: Although theory-driven evaluations should have empirical components, few evaluations of public health interventions quantitatively test the causal model made explicit in the theory of change (ToC). In the context of a shared sanitation trial (MapSan) in Maputo, Mozambique, we report findings of a quantitative process evaluation assessing intervention implementation, participant response and impacts on hypothesised intermediary outcomes on the pathway to trial health outcomes. We examine the utility of path analysis in testing intervention theory using process indicators from the intervention's ToC. Read More

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Predicting the risk of respiratory distress in newborns with congenital pulmonary malformations.

Eur Respir J 2021 Jul 15. Epub 2021 Jul 15.

Inserm UMR 1153, Paris, France.

Objectives: Most children with prenatally diagnosed congenital pulmonary malformations (CPM) are asymptomatic at birth. We aimed to develop a parsimonious prognostic model for predicting the risk of neonatal respiratory distress (NRD) in preterm and term infants with CPM, based on the prenatal attributes of the malformation.

Methods: MALFPULM is a prospective population-based nationally representative cohort including 436 pregnant women. Read More

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An experimental-mathematical approach to predict tumor cell growth as a function of glucose availability in breast cancer cell lines.

PLoS One 2021 13;16(7):e0240765. Epub 2021 Jul 13.

Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, United States of America.

We present the development and validation of a mathematical model that predicts how glucose dynamics influence metabolism and therefore tumor cell growth. Glucose, the starting material for glycolysis, has a fundamental influence on tumor cell growth. We employed time-resolved microscopy to track the temporal change of the number of live and dead tumor cells under different initial glucose concentrations and seeding densities. Read More

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Latent class analysis-derived subphenotypes are generalisable to observational cohorts of acute respiratory distress syndrome: a prospective study.

Thorax 2021 Jul 12. Epub 2021 Jul 12.

Department of Anesthesiology, University of California San Francisco, San Francisco, California, USA.

Rationale: Using latent class analysis (LCA), two subphenotypes of acute respiratory distress syndrome (ARDS) have consistently been identified in five randomised controlled trials (RCTs), with distinct biological characteristics, divergent outcomes and differential treatment responses to randomised interventions. Their existence in unselected populations of ARDS remains unknown. We sought to identify subphenotypes in observational cohorts of ARDS using LCA. Read More

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Risk Prediction Models for Post-Operative Decompensation and Infection in Patients with Cirrhosis: A Veterans Affairs Cohort Study.

Clin Gastroenterol Hepatol 2021 Jul 8. Epub 2021 Jul 8.

Division of Gastroenterology and Hepatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Medicine, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA.

Background And Aims: Patients with cirrhosis have an increased risk of post-operative mortality for a range of surgeries, however they are also at risk of post-operative complications such as infection and cirrhosis decompensation. To date there are no prediction scores that specifically risk stratify patients for these morbidities.

Methods: This was a retrospective study using data of patients with cirrhosis who underwent diverse surgeries in the Veterans Health Administration. Read More

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Lasso estimation of hierarchical interactions for analyzing heterogeneity of treatment effect.

Stat Med 2021 Jul 8. Epub 2021 Jul 8.

Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.

Individuals differ in how they respond to a given treatment. In an effort to predict the treatment response and analyze the heterogeneity of treatment effect, we propose a general modeling framework by identifying treatment-covariate interactions honoring a hierarchical condition. We construct a single-step norm penalty procedure that maintains the hierarchical structure of interactions in the sense that a treatment-covariate interaction term is included in the model only when either the covariate or both the covariate and treatment have nonzero main effects. Read More

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Scalable Sparse Testing Genomic Selection Strategy for Early Yield Testing Stage.

Front Plant Sci 2021 22;12:658978. Epub 2021 Jun 22.

Section of Plant Breeding and Genetics, School of Integrative Plant Sciences, Cornell University, Ithaca, NY, United States.

To enable a scalable sparse testing genomic selection (GS) strategy at preliminary yield trials in the CIMMYT maize breeding program, optimal approaches to incorporate genotype by environment interaction (GEI) in genomic prediction models are explored. Two cross-validation schemes were evaluated: CV1, predicting the genetic merit of new bi-parental populations that have been evaluated in some environments and not others, and CV2, predicting the genetic merit of half of a bi-parental population that has been phenotyped in some environments and not others using the coefficient of determination (CDmean) to determine optimized subsets of a full-sib family to be evaluated in each environment. We report similar prediction accuracies in CV1 and CV2, however, CV2 has an intuitive appeal in that all bi-parental populations have representation across environments, allowing efficient use of information across environments. Read More

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Elementary integrate-and-fire process underlies pulse amplitudes in Electrodermal activity.

PLoS Comput Biol 2021 Jul 7;17(7):e1009099. Epub 2021 Jul 7.

Harvard-Massachusetts Institute of Technology Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.

Electrodermal activity (EDA) is a direct read-out of sweat-induced changes in the skin's electrical conductance. Sympathetically-mediated pulsatile changes in skin sweat measured as EDA resemble an integrate-and-fire process, which yields an inverse Gaussian model as the inter-pulse interval distribution. We have previously showed that the inter-pulse intervals in EDA follow an inverse Gaussian distribution. Read More

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Is a simple model based on two mixing reservoirs able to reproduce the intra-annual dynamics of DOC and NO stream concentrations in an agricultural headwater catchment?

Sci Total Environ 2021 Jun 26;794:148715. Epub 2021 Jun 26.

UMR SAS, INRAE, Institut Agro, 35000 Rennes, France.

Agriculture disturbs the biogeochemical cycles of major elements, which alters the elemental stoichiometry of surface stream waters, with potential impacts on their ecosystems. However, models of catchment hydrology and water quality remain relatively disconnected, even though the observation that dissolved organic carbon (DOC) and nitrate (NO) have opposite spatial and temporal patterns seems relevant for improving our representation of hydrological transport pathways within catchments. We tested the ability of a parsimonious model to simultaneously reproduce intra-annual dynamics of stream flow, DOC and NO concentrations using 15 years of daily data from a small headwater agricultural catchment (AgrHyS observatory). Read More

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CT-Detected Subsolid Nodules: A Predictor of Lung Cancer Development at Another Location?

Cancers (Basel) 2021 Jun 4;13(11). Epub 2021 Jun 4.

Department of Medical Imaging, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.

The purpose of this case-cohort study was to investigate whether the frequency and computed tomography (CT) features of pulmonary nodules posed a risk for the future development of lung cancer (LC) at a different location. Patients scanned between 2004 and 2012 at two Dutch academic hospitals were cross-linked with the Dutch Cancer Registry. All patients who were diagnosed with LC by 2014 and a random selection of LC-free patients were considered. Read More

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Neural Networks as Geometric Chaotic Maps.

Ziwei Li Sai Ravela

IEEE Trans Neural Netw Learn Syst 2021 Jun 30;PP. Epub 2021 Jun 30.

The use of artificial neural networks (NNs) as models of chaotic dynamics has been rapidly expanding. Still, a theoretical understanding of how NNs learn chaos is lacking. Here, we employ a geometric perspective to show that NNs can efficiently model chaotic dynamics by becoming structurally chaotic themselves. Read More

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A clinical diabetes risk prediction model for prediabetic women with prior gestational diabetes.

PLoS One 2021 25;16(6):e0252501. Epub 2021 Jun 25.

Division of Academic Internal Medicine and Geriatrics, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America.

Introduction: Without treatment, prediabetic women with a history of gestational diabetes mellitus (GDM) are at greater risk for developing type 2 diabetes compared with women without a history of GDM. Both intensive lifestyle intervention and metformin can reduce risk. To predict risk and treatment response, we developed a risk prediction model specifically for women with prior GDM. Read More

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A new phylodynamic model of Mycobacterium bovis transmission in a multi-host system uncovers the role of the unobserved reservoir.

PLoS Comput Biol 2021 Jun 25;17(6):e1009005. Epub 2021 Jun 25.

Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom.

Multi-host pathogens are particularly difficult to control, especially when at least one of the hosts acts as a hidden reservoir. Deep sequencing of densely sampled pathogens has the potential to transform this understanding, but requires analytical approaches that jointly consider epidemiological and genetic data to best address this problem. While there has been considerable success in analyses of single species systems, the hidden reservoir problem is relatively under-studied. Read More

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Single-Stage Prediction Models Do Not Explain the Magnitude of Syntactic Disambiguation Difficulty.

Cogn Sci 2021 Jun;45(6):e12988

Department of Linguistics and Center for Data Science, New York University.

The disambiguation of a syntactically ambiguous sentence in favor of a less preferred parse can lead to slower reading at the disambiguation point. This phenomenon, referred to as a garden-path effect, has motivated models in which readers initially maintain only a subset of the possible parses of the sentence, and subsequently require time-consuming reanalysis to reconstruct a discarded parse. A more recent proposal argues that the garden-path effect can be reduced to surprisal arising in a fully parallel parser: words consistent with the initially dispreferred but ultimately correct parse are simply less predictable than those consistent with the incorrect parse. Read More

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Case-Ascertainment Models to Identify Adults with Obstructive Sleep Apnea Using Health Administrative Data: Internal and External Validation.

Clin Epidemiol 2021 17;13:453-467. Epub 2021 Jun 17.

ICES, Ottawa, Toronto, Ontario, Canada.

Background: There is limited evidence on whether obstructive sleep apnea (OSA) can be accurately identified using health administrative data.

Study Design And Methods: We derived and validated a case-ascertainment model to identify OSA using linked provincial health administrative and clinical data from all consecutive adults who underwent a diagnostic sleep study (index date) at two large academic centers (Ontario, Canada) from 2007 to 2017. The presence of moderate/severe OSA (an apnea-hypopnea index≥15) was defined using clinical data. Read More

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Evaluation of a Parsimonious COVID-19 Outbreak Prediction Model: Heuristic Modeling Approach Using Publicly Available Data Sets.

J Med Internet Res 2021 Jul 26;23(7):e28812. Epub 2021 Jul 26.

Center for Biomedical Informatics, Regenstrief Institute, Indianapolis, IN, United States.

Background: The COVID-19 pandemic has changed public health policies and human and community behaviors through lockdowns and mandates. Governments are rapidly evolving policies to increase hospital capacity and supply personal protective equipment and other equipment to mitigate disease spread in affected regions. Current models that predict COVID-19 case counts and spread are complex by nature and offer limited explainability and generalizability. Read More

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Identification and Prediction of Novel Clinical Phenotypes for Intensive Care Patients With SARS-CoV-2 Pneumonia: An Observational Cohort Study.

Front Med (Lausanne) 2021 4;8:681336. Epub 2021 Jun 4.

Department of Intensive Care Medicine, Tongji Medical College, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China.

Phenotypes have been identified within heterogeneous disease, such as acute respiratory distress syndrome and sepsis, which are associated with important prognostic and therapeutic implications. The present study sought to assess whether phenotypes can be derived from intensive care patients with coronavirus disease 2019 (COVID-19), to assess the correlation with prognosis, and to develop a parsimonious model for phenotype identification. Adult patients with COVID-19 from Tongji hospital between January 2020 and March 2020 were included. Read More

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Scores selection via Fisher's discriminant power in PCA-LDA to improve the classification of food data.

Food Chem 2021 Jun 5;363:130296. Epub 2021 Jun 5.

Universidade Federal de Paraíba, Departamento de Química, P.O.Box 5093, CEP 58051-970 João Pessoa, PB, Brazil. Electronic address:

This paper proposes an adaptation of the Fisher's discriminability criterion (named here as discriminant power, DP) for choosing principal components (obtained from Principal Component Analysis, PCA), which will be used to construct supervised Linear Discriminant Analysis (LDA) models for solving classification problems of food data. The proposed PCA-DP-LDA algorithm was then applied to (i) simulated data, (ii) classify soybean oils with respect to expiration date, and (iii) identify cachaça adulteration with wood extracts that simulated aging. For comparison, PCA-DP-LDA was evaluated against conventional PCA-LDA (based on explained variance) and Partial Least Squares-Discriminant Analysis (PLS-DA). Read More

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Two effective clinical prediction models to screen for obstructive sleep apnoea based on body mass index and other parameters.

Sleep Breath 2021 Jun 17. Epub 2021 Jun 17.

Department of Respiratory Medicine, The Second Affiliated Hospital of Soochow University, Soochow University, No. 1055, Sanxiang Road, Suzhou, 215004, Jiangsu, China.

Background And Objective: The diagnosis of obstructive sleep apnea (OSA) relies on polysomnography which is time-consuming and expensive. We therefore aimed to develop two simple, non-invasive models to screen adults for OSA.

Methods: The effectiveness of using body mass index (BMI) and a new visual prediction model to screen for OSA was evaluated using a development set (1769 participants) and confirmed using an independent validation set (642 participants). Read More

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Population Model of Serum Creatinine as Time-Dependent Covariate in Neonates.

AAPS J 2021 Jun 17;23(4):86. Epub 2021 Jun 17.

Department of Development and Regeneration, KU Leuven, Leuven, Belgium.

Serum creatinine (sCr) is a commonly measured biomarker to estimate glomerular filtration rate (GFR) and therefore widely used as a covariate in population pharmacokinetic models of renally excreted drugs. In neonates, sCr dynamically changes during the first few weeks after birth. Missing covariates are a common problem in pharmacokinetic modeling of neonates due to the limited availability of blood sampling in number and volume. Read More

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Understanding the impact of correlation within pair-bonds on Cormack-Jolly-Seber models.

Ecol Evol 2021 Jun 1;11(11):5966-5984. Epub 2021 May 1.

Department of Statistical and Actuarial Sciences Western University London Ontario Canada.

The Cormack-Jolly-Seber (CJS) model and its extensions have been widely applied to the study of animal survival rates in open populations. The model assumes that individuals within the population of interest have independent fates. It is, however, highly unlikely that a pair of animals which have formed a long-term pairing have dissociated fates. Read More

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Parsimonious neural networks learn interpretable physical laws.

Sci Rep 2021 Jun 17;11(1):12761. Epub 2021 Jun 17.

School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA.

Machine learning is playing an increasing role in the physical sciences and significant progress has been made towards embedding domain knowledge into models. Less explored is its use to discover interpretable physical laws from data. We propose parsimonious neural networks (PNNs) that combine neural networks with evolutionary optimization to find models that balance accuracy with parsimony. Read More

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Measurement invariance testing of the patient health questionnaire-9 (PHQ-9) across people with and without diabetes mellitus from the NHANES, EMHS and UK Biobank datasets.

J Affect Disord 2021 Sep 27;292:311-318. Epub 2021 May 27.

McGill University, Montreal, Canada; University of Tübingen, Tübingen, Germany.

Background: The prevalence of depression is higher among those with diabetes than in the general population. The Patient Health Questionnaire (PHQ-9) is commonly used to assess depression in people with diabetes, but measurement invariance of the PHQ-9 across groups of people with and without diabetes has not yet been investigated.

Methods: Data from three independent cohorts from the USA (n=1,886 with diabetes, n=4,153 without diabetes), Quebec, Canada (n= 800 with diabetes, n= 2,411 without diabetes), and the UK (n=4,981 with diabetes, n=145,570 without diabetes), were used to examine measurement invariance between adults with and without diabetes. Read More

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September 2021

Eco-evolutionary optimality as a means to improve vegetation and land-surface models.

New Phytol 2021 Jun 15. Epub 2021 Jun 15.

Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.

Global vegetation and land-surface models embody interdisciplinary scientific understanding of the behaviour of plants and ecosystems, and are indispensable to project the impacts of environmental change on vegetation and the interactions between vegetation and climate. However, systematic errors and persistently large differences among carbon and water cycle projections by different models highlight the limitations of current process formulations. In this review, focusing on core plant functions in the terrestrial carbon and water cycles, we show how unifying hypotheses derived from eco-evolutionary optimality (EEO) principles can provide novel, parameter-sparse representations of plant and vegetation processes. Read More

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Uncontrolled Confounders May Lead to False or Overvalued Radiomics Signature: A Proof of Concept Using Survival Analysis in a Multicenter Cohort of Kidney Cancer.

Front Oncol 2021 27;11:638185. Epub 2021 May 27.

Department of Radiology, Columbia University Irving Medical Center, New York, NY, United States.

Purpose: We aimed to explore potential confounders of prognostic radiomics signature predicting survival outcomes in clear cell renal cell carcinoma (ccRCC) patients and demonstrate how to control for them.

Materials And Methods: Preoperative contrast enhanced abdominal CT scan of ccRCC patients along with pathological grade/stage, gene mutation status, and survival outcomes were retrieved from The Cancer Imaging Archive (TCIA)/The Cancer Genome Atlas-Kidney Renal Clear Cell Carcinoma (TCGA-KIRC) database, a publicly available dataset. A semi-automatic segmentation method was applied to segment ccRCC tumors, and 1,160 radiomics features were extracted from each segmented tumor on the CT images. Read More

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Photoplethysmography Fast Upstroke Time Intervals Can Be Useful Features for Cuff-Less Measurement of Blood Pressure Changes in Humans.

IEEE Trans Biomed Eng 2021 Jun 7;PP. Epub 2021 Jun 7.

Objective: Photoplethysmography (PPG) waveform analysis is being increasingly investigated for continuous, non-invasive, and cuff-less blood pressure (BP) measurement. However, the efficacy of this approach and the useful features and models remain largely unclear. The objectives were to develop easy-to-understand models relating PPG waveform features to BP changes (after a cuff calibration) and to determine their value in BP measurement accuracy. Read More

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NanoTox: Development of a Parsimonious Model for Toxicity Assessment of Metal-Oxide Nanoparticles Using Physicochemical Features.

ACS Omega 2021 May 23;6(17):11729-11739. Epub 2021 Apr 23.

Department of Medical Nanotechnology and Department of Bioinformatics, School of Chemical and BioTechnology, SASTRA Deemed University, Thanjavur 613401, India.

Metal-oxide nanoparticles find widespread applications in mundane life today, and cost-effective evaluation of their cytotoxicity and ecotoxicity is essential for sustainable progress. Machine learning models use existing experimental data and learn quantitative feature-toxicity relationships to yield predictive models. In this work, we adopted a principled approach to this problem by formulating a novel feature space based on intrinsic and extrinsic physicochemical properties, including periodic table properties but exclusive of in vitro characteristics such as cell line, cell type, and assay method. Read More

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Predictors of Psychological Distress and Confidence Negotiating Physical and Social Environments among Mobility Device Users.

Am J Phys Med Rehabil 2021 May 28. Epub 2021 May 28.

Department of Occupational Sciences and Occupational Therapy, Faculty of Medicine, University of British Columbia; International Collaboration on Repair Discoveries (ICORD); Rehabilitation Research Program, Vancouver Coastal Health Research Institute (VCHRI). Department of Rehabilitation, Faculty of Medicine, Université Laval; Centre interdisciplinaire de recherche en réadaptation et en intégration sociale, Centre intégré universitaire de santé et de services sociaux de la Capitale-Nationale. Department of Gerontology, Faculty of Arts and Social Sciences, Simon Fraser University. Department of Occupational Sciences and Occupational Therapy, Faculty of Medicine, University of British Columbia; Rehabilitation Research Program, Vancouver Coastal Health Research Institute (VCHRI). Department of Occupational Sciences and Occupational Therapy, Faculty of Medicine, University of British Columbia; Rehabilitation Research Program, Vancouver Coastal Health Research Institute (VCHRI). Reichwald Family UBC Southern Medical Program Chair in Preventive Medicine; Department of Medicine, Faculty of Medicine; School of Health and Exercise Sciences; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna British Columbia Department of Occupational Sciences and Occupational Therapy, Faculty of Medicine, University of British Columbia; Rehabilitation Research Program, Vancouver Coastal Health Research Institute (VCHRI).

Objective: We conducted an intersectional analysis to explore how demographic characteristics and mobility device use were associated with psychological distress (depression and anxiety) and confidence negotiating physical and social environments.

Design: Cross-sectional data were collected using the Hospital Anxiety and Depression Scale, modified Wheelchair Use Confidence Scale and self-reported functional independence scale.

Participants: The sample included 105 participants. Read More

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