1,291 results match your criteria underestimation small


The impacts of background error covariance on particulate matter assimilation and forecast: An ideal case study with a modal aerosol model over China.

Sci Total Environ 2021 Apr 29;786:147417. Epub 2021 Apr 29.

Guangdong-Hong Kong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China; Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China. Electronic address:

Accurate estimation of background error covariance (BEC) is the key to successful data assimilation (DA). In aerosol three-dimensional variational (3DVAR) DA, the National Meteorological Center (NMC) method is typically applied to estimate BEC, which uses the difference between forecasts of dissimilar lengths valid at the common time. The difference will be considerably small when the underestimation of the aerosol is caused by the lack of emissions or the missing of chemical progress, which makes the aerosol concentration field too difficult to constrain. Read More

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Metabolites of bovine-associated non-aureus staphylococci influence expression of Staphylococcus aureus agr-related genes in vitro.

Vet Res 2021 Apr 29;52(1):62. Epub 2021 Apr 29.

M-Team & Mastitis and Milk Quality Research Unit, Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.

Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We determined whether 34 S. Read More

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Role of Infection and Immunity in Bovine Perinatal Mortality: Part 1. Causes and Current Diagnostic Approaches.

Animals (Basel) 2021 Apr 6;11(4). Epub 2021 Apr 6.

Department of Immunology, Pathophysiology and Veterinary Preventive Medicine, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland.

While non-infectious causes are more commonly diagnosed in cases of bovine perinatal mortality (PM), the proportion caused by infections is highly variable between studies (~5-35%); the reasons for this variation, and possible underestimation, are discussed. The most important pathogen-specific infectious causes of PM are bacteria (in particular, and spp.), viruses (in particular BVDv) and a parasite (). Read More

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Data-driven methods distort optimal cutoffs and accuracy estimates of depression screening tools: a simulation study using individual participant data.

J Clin Epidemiol 2021 Apr 7. Epub 2021 Apr 7.

Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montréal, Québec, Canada; Members of the DEPRESSD EPDS Group: Ying Sun, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada. Electronic address:

Objective: To evaluate, across multiple sample sizes, the degree that data-driven methods result in (1) optimal cutoffs different from population optimal cutoff and (2) bias in accuracy estimates.

Study Design And Setting: 1,000 samples of sample size 100, 200, 500 and 1,000 each were randomly drawn to simulate studies of different sample sizes from a database (N=13,255) synthesized to assess Edinburgh Postnatal Depression Scale (EPDS) screening accuracy. Optimal cutoffs were selected by maximizing Youden's J (sensitivity+specificity-1). Read More

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Peritoneal Metastases From Colorectal Cancer: Defining and Addressing the Challenges.

Front Oncol 2021 16;11:650098. Epub 2021 Mar 16.

Department of Surgery, Research School for Oncology and Developmental Biology, Catharina Hospital Eindhoven, The Netherlands and Maastricht University, Maastricht, Netherlands.

The presence of peritoneal metastases (PM) in patients with colorectal cancer (CRC) is associated with an extremely poor prognosis. The diagnosis of PM is challenging, resulting in an underestimation of their true incidence. While surgery can be curative in a small percentage of patients, effective treatment for non-operable PM is lacking, and clinical and pre-clinical studies are relatively sparse. Read More

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Evaluating and improving the reliability of the UV-persulfate method for the determination of TOC/DOC in surface waters.

Water Res 2021 May 10;196:116918. Epub 2021 Feb 10.

State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address:

The UV-persulfate oxidation method is widely used for determining the total organic carbon concentration of aqueous samples (denoted for convenience as UVP-TOC). However, for some surface water samples, the measurement of TOC by this method can be unreliable, deviating significantly from the true carbon content. In this study, the performance of the UVP-TOC method has been investigated by comparing the results from the analysis of a variety of aqueous samples that included two kinds of surface water samples and related surface water model substances: bovine serum albumin (BSA), sodium alginate (SA), humic acid (HA), tannic acid (TA), benzoic acid (BA) and citric acid (CA), with those from a high-temperature combustion method (elemental analysis); the latter providing the true carbon content value. Read More

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Semi-automatic measurements of foot morphological parameters from 3D plantar foot scans.

J Foot Ankle Res 2021 Mar 17;14(1):18. Epub 2021 Mar 17.

Movement Analysis Laboratory, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136, Bologna, Italy.

Background: Foot healthcare research is focusing increasingly on personalized orthotic and prosthetic devices to address patient-specific morphology and ailments. Customization requires advanced 3D image processing tools to assess foot and leg geometrical parameters and alterations. The aim of this study is to present a new software for the measurement of the foot shape from 3D scans of the foot plantar surface. Read More

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Reduced Fracture Strength of 2D Materials Induced by Interlayer Friction.

Small 2021 Apr 9;17(13):e2005996. Epub 2021 Mar 9.

State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China.

The potential applications of 2D layered materials (2DLMs) as the functional membranes in flexible electronics and nano-electromechanical systems emphasize the role of the mechanical properties of these materials. Interlayer interactions play critical roles in affecting the mechanical properties of 2DLMs, and nevertheless the understanding of their relationship remains incomplete. In the present work, it is reported that the fracture strength of few-layer (FL) WS can be weakened by the interlayer friction among individual layers with the assistance of finite element simulations and density functional theory (DFT) calculations. Read More

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Heroin use cannot be measured adequately with a general population survey.

Addiction 2021 Mar 2. Epub 2021 Mar 2.

University of Maryland, Department of Criminology and Criminal Justice, College Park, MD, USA.

Background: Globally, heroin and other opioids account for more than half of deaths and years-of-life-lost due to drug use and comprise one of the four major markets for illegal drugs. Having sound estimates of the number of problematic heroin users is fundamental to formulating sound health and criminal justice policies. Researchers and policymakers rely heavily upon general population surveys (GPS), such as the US National Survey on Drug Use and Health (NSDUH), to estimate heroin use, without confronting their limitations. Read More

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Measuring the concentration of protein nanoparticles synthesized by desolvation method: Comparison of Bradford assay, BCA assay, hydrolysis/UV spectroscopy and gravimetric analysis.

Int J Pharm 2021 Apr 27;599:120422. Epub 2021 Feb 27.

Department of Biology, Perm State University, 614068, 15 Bukirev str., Perm, Russia; Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center of the Ural Branch of the Russian Academy of Sciences, 614081, 13 Golev str., Perm, Russia.

The desolvation technique is one of the most popular methods for preparing protein nanoparticles for medicine, biotechnology, and food applications. We fabricated 11 batches of BSA nanoparticles and 2 batches of gelatin nanoparticles by desolvation method. BSA nanoparticles from 2 batches were cross-linked by heating at +70 °C for 2 h; other nanoparticles were stabilized by glutaraldehyde. Read More

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Low Reinfection Rates But a High Rate of Complications in THA for Infection Sequelae in Childhood: A Systematic Review.

Clin Orthop Relat Res 2021 05;479(5):1094-1108

R. D'Apolito, G. Bandettini, G. Rossi, F. P. Jacquot, L. Zagra, Hip Department, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.

Background: Childhood hip infections can result in serious sequelae during adulthood, including persistent pain, functional limitations, and premature THA. When THA is performed in patients who had hip joint infections during childhood, surgeons surmise these arthroplasties are at an increased risk of complications and incomplete recovery. However, the degree to which this is true is not well characterized and has varied across a large number of small, retrospective studies. Read More

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Malnutrition screening on hospital admission: impact of overweight and obesity on comparative performance of MUST and PG-SGA SF.

Eur J Clin Nutr 2021 Feb 15. Epub 2021 Feb 15.

Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.

Background/objectives: Traditional malnutrition screening instruments, including the Malnutrition Universal Screening Tool (MUST), strongly rely on low body mass index (BMI) and weight loss. In overweight/obese patients, this may result in underdetection of malnutrition risk. Alternative instruments, like the Patient-Generated Subjective Global Assessment Short Form (PG-SGA SF), include characteristics and risk factors irrespective of BMI. Read More

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February 2021

Precise measurement of the electron beam current in a TEM.

Ultramicroscopy 2021 Apr 3;223:113221. Epub 2021 Feb 3.

Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany.

Modern quantitative TEM methods such as the ζ-factor technique require precise knowledge of the electron beam current. To this end, a macroscopic Faraday cup was designed and constructed. It can replace the viewing screen in the projection chamber of a TEM and guarantees highly accurate measurement of the electron beam with precision only limited by the used amperemeter. Read More

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Analysis of factors associated with discrepancies between predicted and observed liver weight in liver transplantation.

Liver Int 2021 Feb 8. Epub 2021 Feb 8.

ICube, Université de Strasbourg, CNRS UMR 7357, Illkirch, France.

Background: Even using predictive formulas based on anthropometrics in about 30% of subjects, liver weight (LW) cannot be predicted with a ≤20% margin of error. We aimed to identify factors associated with discrepancies between predicted and observed LW.

Methods: In 500 consecutive liver grafts, we tested LW predictive performance using 17 formulas based on anthropometric characteristics. Read More

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February 2021

Comparison of Correction Techniques for the Spill in Effect in Emission Tomography.

IEEE Trans Radiat Plasma Med Sci 2020 Jul 12;4(4):422-432. Epub 2020 Mar 12.

Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, NY.

In positron emission tomography (PET) imaging, accurate clinical assessment is often affected by the partial volume effect (PVE) leading to overestimation (spill-in) or underestimation (spill-out) of activity in various small regions. The spill-in correction, in particular, can be very challenging when the target region is close to a hot background region. Therefore, this study evaluates and compares the performance of various recently developed spill-in correction techniques, namely: background correction (BC), local projection (LP), and hybrid kernelized (HKEM) methods. Read More

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Impact of diffuse layer processes on contaminant forward and back diffusion in heterogeneous sandy-clayey domains.

J Contam Hydrol 2021 Feb 17;237:103754. Epub 2020 Dec 17.

Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 115, 2800 Kgs. Lyngby, Denmark. Electronic address:

Low-permeability aquitards can significantly affect the transport, distribution, and persistence of contaminant plumes in subsurface systems. Although such low-permeability materials are often charged, the key role of charge-induced electrostatic processes during contaminant transport has not been extensively studied. This work presents a detailed investigation exploring the coupled effects of heterogeneous distribution of physical, chemical and electrostatic properties on reactive contaminant transport in field-scale groundwater systems including spatially distributed clay zones. Read More

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February 2021

Unimpaired perception of relative depth from perspective cues in strabismus.

R Soc Open Sci 2020 Dec 23;7(12):200955. Epub 2020 Dec 23.

School of Psychology and Neuroscience, University of St Andrews, St Mary's Quad, St Andrews, Fife KY16 9JP, UK.

Strabismus is a relatively common ophthalmological condition where the coordination of eye muscles to binocularly fixate a single point in space is impaired. This leads to deficits in vision and particularly in three-dimensional (3D) space perception. The exact nature of the deficits in 3D perception is poorly understood as much of understanding has relied on anecdotal reports or conjecture. Read More

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December 2020

Errors in Measuring Glenohumeral Arthrokinematics With 2-Dimensional Fluoroscopy.

J Appl Biomech 2021 Jan 22:1-6. Epub 2021 Jan 22.

Indian Spinal Injuries Centre.

Two-dimensional fluoroscopic imaging allows measurement of small magnitude humeral head translations that are prone to errors due to optical distortion, out-of-plane imaging, repeated manual identification of landmarks, and magnification. This article presents results from in vivo and in vitro fluoroscopy-based experiments that measure the errors and variability in estimating the humeral head translated position in true scapular plane and axillary views. The errors were expressed as bias and accuracy. Read More

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January 2021

Vestibular Perception in Time and Space During Whole-Body Rotation in Humans.

Cerebellum 2021 Jan 14. Epub 2021 Jan 14.

Dizziness center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, 173-82 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, South Korea.

We investigated the vestibular perception of position, velocity, and time (duration) in humans with rotational stimuli including low velocities and small amplitudes. The participants were categorized into young, middle, and old age groups, and each consisted of 10 subjects. Position perception was assessed after yaw rotations ranged from 30 to 180° in both clockwise and counterclockwise directions. Read More

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January 2021

Re-evaluation of the comparative effectiveness of bootstrap-based optimism correction methods in the development of multivariable clinical prediction models.

BMC Med Res Methodol 2021 Jan 7;21(1). Epub 2021 Jan 7.

Department of Data Science, The Institute of Statistical Mathematics, 10-3 Midori-cho, Tachikawa, Tokyo, 190-8562, Japan.

Background: Multivariable prediction models are important statistical tools for providing synthetic diagnosis and prognostic algorithms based on patients' multiple characteristics. Their apparent measures for predictive accuracy usually have overestimation biases (known as 'optimism') relative to the actual performances for external populations. Existing statistical evidence and guidelines suggest that three bootstrap-based bias correction methods are preferable in practice, namely Harrell's bias correction and the . Read More

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January 2021

Accuracy of fluoroscopic examination in the treatment of Bennett's fracture.

BMC Musculoskelet Disord 2021 Jan 4;22(1). Epub 2021 Jan 4.

Department of Hand Surgery, Beijing Ji Shui Tan Hospital and the 4th Medical College of Peking University, Xin jie kou dong jie 31, Xi Cheng Qu, Beijing, 100035, China.

Background: Restoration of joint congruity is an important factor for the prevention of subsequent arthritis in patients with Bennett's fracture. Surgical treatment of Bennett's fracture is thus generally recommended for displaced intra-articular fractures to the proximal aspect of the thumb metacarpal. Fluoroscopic examination is used to evaluate the adequacy of closed reduction after pinning of Bennett's fracture. Read More

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January 2021

Overview of the SAMPL6 pK challenge: evaluating small molecule microscopic and macroscopic pK predictions.

J Comput Aided Mol Des 2021 Feb 4;35(2):131-166. Epub 2021 Jan 4.

Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.

The prediction of acid dissociation constants (pK) is a prerequisite for predicting many other properties of a small molecule, such as its protein-ligand binding affinity, distribution coefficient (log D), membrane permeability, and solubility. The prediction of each of these properties requires knowledge of the relevant protonation states and solution free energy penalties of each state. The SAMPL6 pK Challenge was the first time that a separate challenge was conducted for evaluating pK predictions as part of the Statistical Assessment of Modeling of Proteins and Ligands (SAMPL) exercises. Read More

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February 2021

Public perception of air pollution sources across Europe.

Ambio 2021 Jun 31;50(6):1150-1158. Epub 2020 Dec 31.

Institute of Atmospheric and Climate Sciences, National Research Council, Via Piero Gobetti, 101, 40129, Bologna, Italy.

Air pollution is one of the primary concerns of our society for its effect on human health and the environment. Among the policy measures that can be put in place to limit air pollutant emissions, end-of-pipe technologies and/or regulatory instruments may be implemented through legislative acts. Also, equally important are behavioural measures, requiring citizens' active involvement. Read More

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Methane and nitrous oxide have separated production zones and distinct emission pathways in freshwater aquaculture ponds.

Water Res 2021 Feb 8;190:116739. Epub 2020 Dec 8.

State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address:

Aquaculture systems receive intensive carbon (C) and nitrogen (N) loadings, and are therefore recognized as major anthropogenic sources of methane (CH) and nitrous oxide (NO) emissions. However, the extensively managed aquaculture ponds were identified as a hotspot of CH emission but just a weak NO source. Here, we investigate annual CH and NO fluxes from three earthen ponds used for crab culture, of different sizes, in southeast China. Read More

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February 2021

Comparison of the two up-to-date sequencing technologies for genome assembly: HiFi reads of Pacific Biosciences Sequel II system and ultralong reads of Oxford Nanopore.

Gigascience 2020 12;9(12)

GrandOmics Biosciences, No.1, East Nengyuan Road, Beijing 102200, China.

Background: The availability of reference genomes has revolutionized the study of biology. Multiple competing technologies have been developed to improve the quality and robustness of genome assemblies during the past decade. The 2 widely used long-read sequencing providers-Pacific Biosciences (PacBio) and Oxford Nanopore Technologies (ONT)-have recently updated their platforms: PacBio enables high-throughput HiFi reads with base-level resolution of >99%, and ONT generated reads as long as 2 Mb. Read More

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December 2020

Sampling and processing methods of microplastics in river sediments - A review.

Sci Total Environ 2021 Mar 23;758:143691. Epub 2020 Nov 23.

Faculty of Civil Engineering, University of Applied Sciences Dresden, 01069 Dresden, Germany. Electronic address:

Microplastics (MP) in marine environments attract widespread attention due to their small particle size and potential hazardous impacts on aquatic and terrestrial ecosystems. Compared to marine sediments, knowledge about the occurrence of MP in freshwater sediments, especially in river sediments, is limited. Although MP concentrations in sediments and soils have been reported in a considerable number of studies, no standardized method is available for sampling and sample processing. Read More

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Challenges in the Assessment of Bycatch: Postmortem Findings in Harbor Porpoises () Retrieved From Gillnets.

Vet Pathol 2021 Mar 4;58(2):405-415. Epub 2020 Dec 4.

Division of Pathology, Department of Biomolecular Health Sciences, 90051Faculty of Veterinary Medicine, Utrecht University, The Netherlands.

Bycatch is considered one of the most significant threats affecting cetaceans worldwide. In the North Sea, bottom-set gillnets are a specific risk for harbor porpoises (). Methods to estimate bycatch rates include on-board observers, remote electronic monitoring, and fishermen voluntarily reporting; none of these are systematically conducted. Read More

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A systematic protocol of microplastics analysis from their identification to quantification in water environment: A comprehensive review.

J Hazard Mater 2021 02 19;403:124049. Epub 2020 Sep 19.

Department of Environmental Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, South Korea. Electronic address:

With microplastics (MPs) being detected in aquatic environments, numerous studies revealed that they caused severe environmental issues, including damage to ecosystems and human health. MPs transport persistent organic pollutants by adsorbing them, and in nanoplastics this phenomenon is exacerbated by increased surface area. Despite their environmental risk, systematic protocol for qualitative and quantitative analysis are yet to be established in environmental analytical chemistry. Read More

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February 2021

Comparison of the Ekblom-Bak Submaximal Test to a Maximal Test in a Cohort of Healthy Younger and Older Adults in the United States.

Front Physiol 2020 6;11:550285. Epub 2020 Nov 6.

Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, United States.

Cardiorespiratory fitness (CRF) is routinely investigated in diverse populations, including in older adults of varying physical activity levels. Commonly performed maximal exercise testing protocols might be contraindicated and/or inadequate for older individuals who have physical or cognitive impairment. Moreover, early termination of an attempted maximal exercise test could result in underestimation of CRF in this population. Read More

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November 2020

An international multi-center investigation on the accuracy of radionuclide calibrators in nuclear medicine theragnostics.

EJNMMI Phys 2020 Nov 23;7(1):69. Epub 2020 Nov 23.

Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P.O. Box 5800, 6202, AZ, Maastricht, The Netherlands.

Background: Personalized molecular radiotherapy based on theragnostics requires accurate quantification of the amount of radiopharmaceutical activity administered to patients both in diagnostic and therapeutic applications. This international multi-center study aims to investigate the clinical measurement accuracy of radionuclide calibrators for 7 radionuclides used in theragnostics: Tc, In, I, I, I, Lu, and Y.

Methods: In total, 32 radionuclide calibrators from 8 hospitals located in the Netherlands, Belgium, and Germany were tested. Read More

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November 2020