scholarly journals A threshold-free approach with age-dependency for estimating malaria seroprevalence

2022 ◽  
Vol 21 (1) ◽  
Author(s):  
Irene Kyomuhangi ◽  
Emanuele Giorgi
Keyword(s):  
Age Groups ◽  
Standard Approach ◽  
Parameter Estimates ◽  
The Novel ◽  
Age Dependency ◽  
Cross Sectional ◽  
Statistical Framework ◽  
Novel Approach ◽  
Current Threshold

Abstract Background In malaria serology analysis, the standard approach to obtain seroprevalence, i.e the proportion of seropositive individuals in a population, is based on a threshold which is used to classify individuals as seropositive or seronegative. The choice of this threshold is often arbitrary and is based on methods that ignore the age-dependency of the antibody distribution. Methods Using cross-sectional antibody data from the Western Kenyan Highlands, this paper introduces a novel approach that has three main advantages over the current threshold-based approach: it avoids the use of thresholds; it accounts for the age dependency of malaria antibodies; and it allows us to propagate the uncertainty from the classification of individuals into seropositive and seronegative when estimating seroprevalence. The reversible catalytic model is used as an example for illustrating how to propagate this uncertainty into the parameter estimates of the model. Results This paper finds that accounting for age-dependency leads to a better fit to the data than the standard approach which uses a single threshold across all ages. Additionally, the paper also finds that the proposed threshold-free approach is more robust against the selection of different age-groups when estimating seroprevalence. Conclusion The novel threshold-free approach presented in this paper provides a statistically principled and more objective approach to estimating malaria seroprevalence. The introduced statistical framework also provides a means to compare results across studies which may use different age ranges for the estimation of seroprevalence.

Abstract 88: Increasing False Positive Diagnoses May Lead to Overestimation of Stroke Incidence, Particularly in the Young

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Abhinav J Appukutty ◽  
Lesli E Skolarus ◽  
Mellanie V Springer ◽  
William J Meurer ◽  
James F Burke
Keyword(s):  
Older Adults ◽  
False Positive ◽  
Age Groups ◽  
Vascular Risk Factor ◽  
The United States ◽  
Cross Sectional ◽  
Stroke Incidence ◽  
Ed Visits ◽  
Over Time

Introduction: Stroke incidence is reportedly increasing in younger adults. While increasing vascular risk factor prevalence has been suggested as a cause, the reasons for rising stroke incidence in the young are not clear. We explored several alternate explanations: trends in neurologically-focused emergency department (ED) visits, differential diagnostic classification of stroke and TIA over time, and changes in the use of advanced imaging in young and older adults. Methods: We performed a retrospective, serial, cross-sectional study on a nationally representative sample of all ED visits in the United States to quantify changes in patterns of neurologically-focused ED visits, stroke and TIA diagnoses, and rates of MRI utilization for young (18 – 44 years) and older (65+ years) adults over a 17-year period (1995 – 2000; 2005 – 2015) using National Hospital Ambulatory Medical Care Survey (NHAMCS) data. Results: In young adults, 0.4% (95% CI 0.3% – 0.5%) of neurologically-focused ED visits resulted in a primary diagnosis of stroke vs. 6.8% (95% CI 6.2% – 7.5%) for older adults. In both populations, the incidence of neurologically-focused ED visits has increased over time (+111/100,000 population/year, 95% CI +94 – +130 in the young vs. +70/100,000 population/year, 95% CI +34 – +108 in older adults). There was no evidence of differential classification of TIA to stroke over time (OR 1.001 per year, 95% CI 0.926 – 1.083 in the young; OR 1.003 per year, 95% CI 0.982 – 1.026 in older adults) and no evidence of disproportionate rise in MRI utilization for neurologically-focused ED visits in the young (OR 1.057 per year, 95% CI 1.028 – 1.086 in the young; OR 1.095 per year, 95% CI 1.066 – 1.125 in older adults). Conclusions: If the specificity of stroke diagnosis amongst ED visits is similar amongst young and older populations, then the combination of data observed here, including (1) a lower prior probability of stroke diagnoses in the young and (2) an increasing trend in neurologically-focused ED visits in both age groups, suggests that false positive diagnoses will increase over time, with a faster rise in the young compared to older adults. These data suggest a potential explanation that may contribute to higher stroke incidence in the young and merits further scrutiny.

Keratoconus staging by decades: a baseline ABCD classification of 1000 patients in the Homburg Keratoconus Center

2020 ◽  
pp. bjophthalmol-2020-316789
Author(s):  
Elias Flockerzi ◽  
Kassandra Xanthopoulou ◽  
Susanne Christiane Goebels ◽  
Elena Zemova ◽  
Sonia Razafimino ◽  
...  
Keyword(s):  
Age Groups ◽  
Cross Sectional Study ◽  
Grading System ◽  
Matched Pairs ◽  
Corneal Curvature ◽  
Cross Sectional ◽  
Stage Distribution ◽  
Significant Difference ◽  
Advanced Stages

BackgroundThis retrospective cross-sectional study aims to analyse the keratoconus (KC) stage distribution at different ages within the Homburg Keratoconus Center (HKC).Methods1917 corneae (1000 patients) were allocated to decades of age, classified according to Belin’s ABCD KC grading system and the stage distribution was analysed.Results73 per cent (n=728) of the patients were males, 27% (n=272) were females. The highest KC prevalence occurred between 21 and 30 years (n=585 corneae, 294 patients). Regarding anterior (A) and posterior (B) curvature, the frequency of A was significantly higher than B in all age groups for stage 0, 1 and 2 (A0>B0; A1>B1; A2>B2; p<0.03, Wilcoxon matched-pairs test). There was no significant difference between the number of A3 and B3, but significantly more corneae were classified as B4 than A4 in all age groups (p<0.02). The most frequent A|B combinations were A4|B4 (n=451), A0|B0 (n=311), A2|B4 (n=242), A2|B2 (n=189) and A1|B2 (n=154). Concerning thinnest pachymetry (C), most corneae in all age groups were classified as C0>C1>C2>C3>C4 (p<0.04, Wilcoxon matched-pairs test). For the best distance visual acuity (D), a significantly higher number of corneae were classified as D1 compared to D0 (p<0.008; D1>D0>D2>D3>D4).ConclusionThe stage distributions in all age groups were similar. Early KC rather becomes manifest in the posterior than the anterior corneal curvature whereas advanced stages of posterior corneal curvature coincide with early and advanced stages of anterior corneal curvature. Thus, this study emphasises the necessity of posterior corneal surface assessment in KC as enabled by the ABCD grading system.

scholarly journals Language Learning of Children With Typical Development Using a Deductive Metalinguistic Procedure

2014 ◽  
Vol 57 (2) ◽  
pp. 509-523 ◽  
Author(s):  
Lizbeth H. Finestack
Keyword(s):  
Language Learning ◽  
Cognitive Abilities ◽  
Age Groups ◽  
Receptive Language ◽  
The Novel ◽  
Language Abilities ◽  
Cross Sectional ◽  
Teaching Procedure ◽  
Study Results ◽  
Study Participants

Purpose In the current study, the author aimed to determine whether 4- to 6-year-old typically developing children possess requisite problem-solving and language abilities to produce, generalize, and retain a novel verb inflection when taught using an explicit, deductive teaching procedure. Method Study participants included a cross-sectional sample of 4-, 5-, and 6-year-old children with typical cognitive and language development. The 66 participants were randomly assigned to either a deductive or inductive teaching condition in which they were taught a novel gender morphological inflection across 4 sessions. Learning was assessed on the basis of performance on learning, generalization, and maintenance probes. Results Across all age groups, children were more likely to successfully use the novel gender form when taught using the deductive procedure than if taught using the inductive procedure (Φ range: .33–.73). Analyses within each age group revealed a robust effect for the 5-year-old children, with less consistent effects across the other age groups. Conclusions Study results suggest that 4- to 6-year-old children with typical language and cognitive abilities are able to make use of a deductive language teaching procedure when learning a novel gender inflection. Evidence also suggests that this effect is driven by expressive and receptive language ability.

scholarly journals Evaluation of Cross-Sectional Root Canal Shape and Presentation of New Classification of Its Changes Using Cone-Beam Computed Tomography Scanning

2020 ◽  
Vol 10 (13) ◽  
pp. 4495 ◽  
Author(s):  
Svetlana Razumova ◽  
Anzhela Brago ◽  
Ammar Howijieh ◽  
Haydar Barakat ◽  
Yuliya Kozlova ◽  
...  
Keyword(s):  
Root Canal ◽  
Age Groups ◽  
Cone Beam ◽  
New Classification ◽  
Cross Sectional ◽  
Computed Tomography Scanning ◽  
The Cross ◽  
Shape Changes ◽  
Tomography Scanning

The root canal system is considering the most important factor in endodontic treatment, due to the complexity of its anatomy and morphology. The aim of this study was to evaluate the cross-sectional root canal shape in three thirds (coronal, middle, apical) in different age groups using cone-beam computed tomography scanning (CBCT) and to present a new classification for root canal shape changes. This cross-sectional study included 300 CBCT scans for patient aged 20–70, and these scans were evaluated to study the morphology of the cross-sectional root canal shape in coronal, middle, and apical thirds among three age groups, namely the young (20–44), middle (45–59), and elderly (60–70). The root canal shape was classified as round, oval, long oval, and ribbon (with or without isthmus). The cross-sectional root canal shape was identified in two groups: canals with an unchanging (constant) shape and canals with changing shape. In turn, in canals with changing shape, the change could be identified in the region of the middle or apical thirds of the canal. The results showed that root canal shape changes in two cases: (1) the presence of one or more canals in the root (with or without isthmus between them), and (2) with age, as it was observed that the cross-sectional shape of the root canal becomes round in the apical third with age. A new classification of the changes of root canal shape in three thirds (coronal, middle, apical) was presented in this study.

Semi-Supervised Classification with Co-Training for Deep Web

2010 ◽  
Vol 439-440 ◽  
pp. 183-188 ◽  
Author(s):  
Wei Fang ◽  
Zhi Ming Cui
Keyword(s):  
Supervised Classification ◽  
Deep Web ◽  
Unlabeled Data ◽  
Supervised Machine Learning ◽  
Web Pages ◽  
The Novel ◽  
Training Process ◽  
Novel Approach ◽  
The Cost

The main problems in Web Pages classification are lack of labeled data, as well as the cost of labeling the unlabeled data. In this paper we discuss the application of semi-supervised machine learning method co-training on classification of Deep Web query interfaces to boost the performance of a classifier. Then, Bayes and Maxim Entropy algorithm are co-operated to incorporate labeled data with unlabeled data in training process incrementally. Our experiment results show the novel approach has a promising performance.

Opinion Mining with SentiWordNet

2010 ◽  
pp. 266-286 ◽  
Author(s):  
Bruno Ohana ◽  
Brendan Tierney
Keyword(s):  
Opinion Mining ◽  
Sentiment Classification ◽  
The Novel ◽  
Data Set ◽  
Learning Classifier ◽  
Novel Approach ◽  
Supervised Methods ◽  
Classification Tasks ◽  
Film Reviews

Opinion Mining is an emerging field of research concerned with applying computational methods to the treatment of subjectivity in text, with a number of applications in fields such as recommendation systems, contextual advertising and business intelligence. In this chapter the authors survey the area of opinion mining and discuss the SentiWordNet lexicon of sentiment information for terms derived from WordNet. Furthermore, the results of their research in applying this lexicon to sentiment classification of film reviews along with a novel approach that leverages opinion lexicons to build a data set of features used as input to a supervised learning classifier are also presented. The results obtained are in line with other experiments based on manually built opinion lexicons with further improvements obtained by using the novel approach, and are indicative that lexicons built using semi supervised methods such as SentiWordNet can be an important resource in sentiment classification tasks. Considerations on future improvements are also presented based on a detailed analysis of classification results.

High-Tech Video Capture and Analysis for Counting Park Users

2020 ◽  
Vol 3 (2) ◽  
pp. 147-156
Author(s):  
Richard R. Suminski ◽  
Gregory M. Dominick ◽  
Philip Saponaro ◽  
Elizabeth M. Orsega-Smith ◽  
Eric Plautz ◽  
...  
Keyword(s):  
Computer Vision ◽  
Traditional Approach ◽  
Age Groups ◽  
Point Of View ◽  
High Tech ◽  
The Novel ◽  
Good Reliability ◽  
Novel Approach ◽  
Study Support ◽  
Number Of Individuals

Today’s technology could contribute substantially to measuring physical activity. The current study evaluated traditional and novel approaches for assessing park use. The traditional approach involved a trained observer performing the System for Observing Play and Recreation in Communities (SOPARC) at 14 parks while wearing a point-of-view, wearable video device (WVD). The novel approach utilized computer vision to count park users in the WVD videos taken during in-person SOPARCs. Both approaches were compared to criterion counts from expert reviews of the WVD videos. In the 676 scans made during in-person SOPARCs, 293 individuals were observed while 341 were counted by experts in the corresponding WVD videos. When using scans/videos having individuals in them (84 scans/videos), intra-class correlations (ICC) indicated good-to-excellent reliability between in-person SOPARC and experts for counts of total women and men, within age groups (except seniors), of Blacks and Whites, and within intensity categories (ICCs > .87; p < 0.001). In a subsample of 42 scans/videos, 174 individuals were counted using computer vision and 213 by experts. When using 27 of the 42 WVD videos with individuals in them, ICCs indicated good reliability between computer vision and expert reviews (ICC = .83; p < 0.001). Bland-Altman analysis showed the concurrence of expert counts with both in-person SOPARC and computer vision counts decreased as the number of individuals in a scan/video increased. The results of this study support the use of a highly discrete method for obtaining point-of-view videos and the application of computer vision for automating the counting of park users in the videos.

scholarly journals Comparison of Body Mass Index and fat percentage criteria classification of 7–13 year-old rural boys in South Africa

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Maya van Gent ◽  
Anita Pienaar ◽  
Habib Noorbhai
Keyword(s):  
Nutritional Status ◽  
Statistical Significance ◽  
Age Groups ◽  
Peak Height ◽  
Height Velocity ◽  
Fat Percentage ◽  
Peak Height Velocity ◽  
Cross Sectional ◽  
Kappa Agreement

Abstract Background The aim of this paper was to investigate whether BMI and fat percentage classification criteria, would classify a sample of 7–13 year old boys from a rural background in similar nutritional categories. Methods A cross-sectional study with a stratified random sampling included 601 rural boys (7–13 years old). Fat percentage criteria classification and BMI were calculated and compared. Maturity status, and age at peak height velocity (PHV) were indirectly determined. Statistical techniques included descriptive statistics, Pearson product correlation coefficients, the Kappa agreement test and the McNemar’s test. The level of statistical significance was set at p ≤ 0.05. Results All age groups presented with statistically significant high correlations between BMI and fat percentage, and low to medium correlations between fat percentage and maturity age (MA). Measurement of agreement between BMI and fat percentage classifications showed poor to fair agreements for all age groups, with the exception of the eight-year old group which presented a moderate agreement. Conclusions Classifications based on BMI and fat percentage, results in different classifications for the same population. Until further research has been done to determine the best classification for nutritional status, it is recommended that both classification methods be used for more accurate classification of nutritional status.

scholarly journals A new classification of cross-sectional root canal shape changes, a cone-beam computed tomography study

2020 ◽  
Author(s):  
Svetlana Razumova ◽  
Anzhela Brago ◽  
Haydar Barakat ◽  
Ammar Howijieh ◽  
Yuliya Kozlova ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Root Canal ◽  
Age Groups ◽  
Cone Beam ◽  
New Classification ◽  
Cross Sectional ◽  
The Cross ◽  
Shape Changes

Abstract Background: The root canal system is considering the most important factor in endodontic treatment, due to the complexity of its anatomy and morphology. The aim of this study was to present a new classification of root canal shape changes in three thirds (coronal, middle, apical) in different age groups using cone-beam computed tomography scanning.Materials and methods: 300 CBCT scans for patient aged 20-70 were evaluated to study the morphology of the cross-sectional root canal shape in coronal, middle and apical thirds among three age groups; young (20-44), middle (45-59) and elderly (60-70). The root canal shape was classified as follow: round, oval, ribbon. Results: The cross-sectional root canal shape was identified in two groups: canals with an unchanging (constant) shape and canals with changing shape. In turn, in canals with changing shape, the change could be identified in the region of the middle or apical thirds of the canal. The results showed that root canal shape changes in two cases: 1) the presence of one or more canals in the root (with or without isthmus between them), 2) with age, as it was observed that the cross-sectional shape of the root canal becomes round in the apical third with age.Conclusion: A new classification of the changes of root canal shape in three thirds (coronal, middle, apical) was presented in this study.

scholarly journals Plaque Layer Identification in IVUS Images by Iterative based Energy Minimization of Contour Method (IEMCM)

2019 ◽  
Vol 8 (3) ◽  
pp. 5392-5397
Keyword(s):  
Energy Minimization ◽  
Shape Parameter ◽  
Input Image ◽  
Contour Method ◽  
The Novel ◽  
Challenging Problem ◽  
Cross Sectional ◽  
Ultrasound Study ◽  
Novel Approach ◽  
Layer Analysis

Atherosclerotic plaque is the major cause of coronary heart artery diseases. Heart artery plaque layer analysis is one of the most important and challenging problem, which can be determined by using Intravascular Ultrasound (IVUS) Cross Sectional images, which is an excellent ultrasound study system for extracting and to easily identify the plaque layer by using the shape parameter measurements. This paper presents and elucidates the novel approach to find out the plaque layer with the help of the artery cross sectional layers determination, which are adventitia, media, intima and lumen layers. This system measures the layer’s performance to make the clear way to identify the plaque layer, which proposes a new method namely Iterative based Energy Minimization of Contour method (IEMCM). The cross sectional IVUS acts as an input image for processing and analysis of the plaque layer based on the IVUS Simulation study Measurements of coronary vessel wall dimensions and shape measurements. The proposed method produced high accuracy when compared to the existing methods

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