Observer Variation
Reproducibility of Results
Integrated visualization of functional and anatomic brain data: a validation study. (1/5805)
Two-dimensional SPECT display and three methods for integrated visualization of SPECT and MRI patient data are evaluated in a multiobserver study to determine whether localization of functional data can be improved by adding anatomical information to the display. METHODS: SPECT and MRI data of 30 patients were gathered and presented using four types of display: one of SPECT in isolation, two integrated two-dimensional displays and one integrated three-dimensional display. Cold and hot spots in the peripheral cortex were preselected and indicated on black-and-white hard copies of the image data. Nuclear medicine physicians were asked to assign the corresponding spots in the image data on the computer screen to a lobe and a gyrus and give a confidence rating for both localizations. Interobserver agreement using kappa statistics and average confidence ratings were assessed to interpret the reported observations. RESULTS: Both the interobserver agreement and the confidence of the observers were greater for the integrated two-dimensional displays than for the two-dimensional SPECT display. An additional increase in agreement and confidence was seen with the integrated three-dimensional display. CONCLUSION: Integrated display of SPECT and MR brain images provides better localization of cerebral blood perfusion abnormalities in the peripheral cortex in relation to the anatomy of the brain than single-modality display and increases the confidence of the observer. (+info)The Sock Test for evaluating activity limitation in patients with musculoskeletal pain. (2/5805)
BACKGROUND AND PURPOSE: Assessment within rehabilitation often must reflect patients' perceived functional problems and provide information on whether these problems are caused by impairments of the musculoskeletal system. Such capabilities were examined in a new functional test, the Sock Test, simulating the activity of putting on a sock. SUBJECTS AND METHODS: Intertester reliability was examined in 21 patients. Concurrent validity, responsiveness, and predictive validity were examined in a sample of 337 patients and in subgroups of this sample. RESULTS: Intertester reliability was acceptable. Sock Test scores were related to concurrent reports of activity limitation in dressing activities. Scores also reflected questionnaire-derived reports of problems in a broad range of activities of daily living and pain and were responsive to change over time. Increases in age and body mass index increased the likelihood of Sock Test scores indicating activity limitation. Pretest scores were predictive of perceived difficulties in dressing activities after 1 year. CONCLUSION AND DISCUSSION: Sock Test scores reflect perceived activity limitations and restrictions of the musculoskeletal system. (+info)Identifying homologous anatomical landmarks on reconstructed magnetic resonance images of the human cerebral cortical surface. (3/5805)
Guided by a review of the anatomical literature, 36 sulci on the human cerebral cortical surface were designated as homologous. These sulci were assessed for visibility on 3-dimensional images reconstructed from magnetic resonance imaging scans of the brains of 20 normal volunteers by 2 independent observers. Those sulci that were found to be reproducibly identifiable were used to define 24 landmarks around the cortical surface. The interobserver and intraobserver variabilities of measurement of the 24 landmarks were calculated. These reliably reproducible landmarks can be used for detailed morphometric analysis, and may prove helpful in the analysis of suspected cerebral cortical structured abnormalities in patients with such conditions as epilepsy. (+info)Venous duplex scanning of the leg: range, variability and reproducibility. (4/5805)
Despite the many studies on venous haemodynamics using duplex, only a few evaluated the normal values, variability and reproducibility. Therefore, the range and variability of venous diameter, compressibility, flow and reflux were measured. To obtain normal values, 42 healthy individuals (42 limbs, 714 vein segments) with no history of venous disease were scanned by duplex. To determine the reproducibility the intra-observer variability was measured in 11 healthy individuals (187 vein segments) and the inter-observer variability in 15 healthy individuals (255 vein segments) and 13 patients (169 vein segments) previously diagnosed with deep venous thrombosis. Of the 714 normal vein segments, 708 (99%) were traceable, including the crural veins. Of the traceable vein segments, 675 (95%) were compressible and in 696 (98%) flow was present. Of the 42 common femoral vein segments, in 25 (60%) the reflux duration exceeded 1.0 s, but in the other proximal vein segments the reflux duration was less than 1.0 s (95% confidence interval 3.0-10.0). With the exception of the distal long saphenous vein, in the distal vein segments the reflux duration was less than 0.5 s (95% confidence interval 3.5-8.2). The coefficient of variation of the diameter measurements ranged from 14 to 50% and that of the reflux measurements from 28 to 60%. The kappa-coefficient of the inter-observer variability in the classification of compressibility measurements in the patients was 0. 77 and that of the reflux measurements was 0.86. This study shows that almost all veins were compressible in healthy individuals, except the distal femoral veins. In healthy individuals the duration of reflux of the proximal veins was less than 1.0 s and in the distal veins it was less than 0.5 s. The inter-observer variability of the reflux and compressibility measurements in the patients was good. (+info)Computed radiography dual energy subtraction: performance evaluation when detecting low-contrast lung nodules in an anthropomorphic phantom. (5/5805)
A dedicated chest computed radiography (CR) system has an option of energy subtraction (ES) acquisition. Two imaging plates, rather than one, are separated by a copper filter to give a high-energy and low-energy image. This study compares the diagnostic accuracy of conventional computed radiography to that of ES obtained with two radiographic techniques. One soft tissue only image was obtained at the conventional CR technique (s = 254) and the second was obtained at twice the radiation exposure (s = 131) to reduce noise. An anthropomorphic phantom with superimposed low-contrast lung nodules was imaged 53 times for each radiographic technique. Fifteen images had no nodules; 38 images had a total of 90 nodules placed on the phantom. Three chest radiologists read the three sets of images in a receiver operating characteristic (ROC) study. Significant differences in Az were only found between (1) the higher exposure energy subtracted images and the conventional dose energy subtracted images (P = .095, 90% confidence), and (2) the conventional CR and the energy subtracted image obtained at the same technique (P = .024, 98% confidence). As a result of this study, energy subtracted images cannot be substituted for conventional CR images when detecting low-contrast nodules, even when twice the exposure is used to obtain them. (+info)Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature. (6/5805)
The epidemiologic literature in the English language regarding intake of tomatoes and tomato-based products and blood lycopene (a compound derived predominantly from tomatoes) level in relation to the risk of various cancers was reviewed. Among 72 studies identified, 57 reported inverse associations between tomato intake or blood lycopene level and the risk of cancer at a defined anatomic site; 35 of these inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increased the risk of cancer at any of the investigated sites. About half of the relative risks for comparisons of high with low intakes or levels for tomatoes or lycopene were approximately 0.6 or lower. The evidence for a benefit was strongest for cancers of the prostate, lung, and stomach. Data were also suggestive of a benefit for cancers of the pancreas, colon and rectum, esophagus, oral cavity, breast, and cervix. Because the data are from observational studies, a cause-effect relationship cannot be established definitively. However, the consistency of the results across numerous studies in diverse populations, for case-control and prospective studies, and for dietary-based and blood-based investigations argues against bias or confounding as the explanation for these findings. Lycopene may account for or contribute to these benefits, but this possibility is not yet proven and requires further study. Numerous other potentially beneficial compounds are present in tomatoes, and, conceivably, complex interactions among multiple components may contribute to the anticancer properties of tomatoes. The consistently lower risk of cancer for a variety of anatomic sites that is associated with higher consumption of tomatoes and tomato-based products adds further support for current dietary recommendations to increase fruit and vegetable consumption. (+info)The psychometric properties of clinical rating scales used in multiple sclerosis. (7/5805)
OullII;l y Many clinical rating scales have been proposed to assess the impact of multiple sclerosis on patients, but only few have been evaluated formally for reliability, validity and responsiveness. We assessed the psychometric properties of five commonly used scales in multiple sclerosis, the Expanded Disability Status Scale (EDSS), the Scripps Neurological Rating Scale (SNRS), the Functional Independence Measure (FIM), the Ambulation Index (AI) and the Cambridge Multiple Sclerosis Basic Score (CAMBS). The score frequency distributions of all five scales were either bimodal (EDSS and AI) or severely skewed (SNRS, FIM and CAMBS). The reliability of each scale depended on the definition of 'agreement'. Inter-and intra-rater reliabilities were high when 'agreement' was considered to exist despite a difference of up to 1.0 EDSS point (two 0.5 steps), 13 SNRS points, 9 FIM points, 1 AI point and 1 point on the various CAMBS domains. The FIM, AI, and the relapse and progression domains of the CAMBS were sensitive to clinical change, but the EDSS and the SNRS were unresponsive. The validity of these scales as impairment (SNRS and EDSS) and disability (EDSS, FIM, AI and the disability domain of the CAMBS) measures was established. All scales correlated closely with other measures of handicap and quality of life. None of these scales satisfied the psychometric requirements of outcome measures completely, but each had some desirable properties. The SNRS and the EDSS were reliable and valid measures of impairment and disability, but they were unresponsive. The FIM was a reliable, valid and responsive measure of disability, but it is cumbersome to administer and has a limited content validity. The AI was a reliable and valid ambulation-related disability scale, but it was weakly responsive. The CAMBS was a reliable (all four domains) and responsive (relapse and progression domains) outcome measure, but had a limited validity (handicap domain). These psychometric properties should be considered when designing further clinical trials in multiple sclerosis. (+info)Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea. (8/5805)
The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea. (+info)Observer variation, also known as inter-observer variability or measurement agreement, refers to the difference in observations or measurements made by different observers or raters when evaluating the same subject or phenomenon. It is a common issue in various fields such as medicine, research, and quality control, where subjective assessments are involved.
In medical terms, observer variation can occur in various contexts, including:
1. Diagnostic tests: Different radiologists may interpret the same X-ray or MRI scan differently, leading to variations in diagnosis.
2. Clinical trials: Different researchers may have different interpretations of clinical outcomes or adverse events, affecting the consistency and reliability of trial results.
3. Medical records: Different healthcare providers may document medical histories, physical examinations, or treatment plans differently, leading to inconsistencies in patient care.
4. Pathology: Different pathologists may have varying interpretations of tissue samples or laboratory tests, affecting diagnostic accuracy.
Observer variation can be minimized through various methods, such as standardized assessment tools, training and calibration of observers, and statistical analysis of inter-rater reliability.
Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.
In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.
The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.
Genetic variation refers to the differences in DNA sequences among individuals and populations. These variations can result from mutations, genetic recombination, or gene flow between populations. Genetic variation is essential for evolution by providing the raw material upon which natural selection acts. It can occur within a single gene, between different genes, or at larger scales, such as differences in the number of chromosomes or entire sets of chromosomes. The study of genetic variation is crucial in understanding the genetic basis of diseases and traits, as well as the evolutionary history and relationships among species.
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Inter-observer variation between pathologists in diffuse parenchymal lung disease | Thorax
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Diagnosis2
- Observer variations in the diagnosis of stroke. (julkari.fi)
- Observer variation in histopathological diagnosis and grading of cervical intraepithelial neoplasia. (bmj.com)
Intra6
- The aim of this study was to determine the intra- and inter-observer variation in the use of a system designed for exact measurements from standard optic nerve head photographs. (nih.gov)
- Intra-observer variances were 0.001 +/- 0.001 mm2 for cup area (mean +/- SD), 0.002 +/- 0.002 mm2 for disc area and 0.002 +/- 0.003 mm2 for rim area. (nih.gov)
- These values for intra-observer variance were comparable with the results obtained using manual planimetric techniques. (nih.gov)
- Intra-observer variance for disc area was significantly larger for the less trained of the two experienced observers. (nih.gov)
- This process is laborious and subject to considerable inter- and intra-observer variations. (nature.com)
- This study looked at intra-observer and inter-observer reliability among three emergency physicians (EPs) using three different imaging protocols. (medscimonit.com)
Variability2
- Morphological variability or inter-observer bias? (researchgate.net)
- Moreover, wide variation between individual measurements was reported, indicating high observer variability (1;2). (escardio.org)
Inter-observer re1
- These data suggest comparable precision and inter-observer reliability can be achieved. (medscimonit.com)
Genetic variations2
- As one can imagine, identification of a given patient's genetic variations via gene sequencing is merely the tip of the proverbial iceberg. (mlo-online.com)
- Acquiring knowledge of genetic variations from a test that was not ordered with the primary intent to obtain that information presents a dilemma. (mlo-online.com)
Abstract1
- This is the abstract base class for all observers. (blackwasp.co.uk)
Observation1
- Discovered in 1908 by Annie Jump Cannon (Figure 1), SU Tau has been under constant observation by BAA VSS observers since 1962 (Figure 2). (britastro.org)
Depend upon2
- In addition, for the same observer the reading could depend upon the time of incubation. (erowid.org)
- Many other observer objects that depend upon the subject can subscribe to it so that they are immediately and automatically notified of any changes to the subject's state. (blackwasp.co.uk)
Considerable1
- There was a considerable variation in the reading of the slides between different persons. (erowid.org)
Differences1
- The absolute differences between the two observers ranged from -0.35 to +0.20 mm2 (-0.08 +/- 0.11 mm2) for cup area, from -0.38 to +0.15 mm2 (-0.08 +/- 0.11 mm2) for disc area and from -0.29 to +0.34 mm2 (-0.06 +/- 0.12 mm2) for rim area. (nih.gov)
Measurements1
- Masked measurements were made 3 times by 2 observers, from stereophotographs of the optic nerve head of 56 eyes from 30 glaucoma suspects. (nih.gov)
Pattern13
- Add a digit pattern (in this case 5) that is defined by yellow-blue variation only. (webexhibits.org)
- This pattern can be perceived by any observer who is able to distinguish between yellow and blue. (webexhibits.org)
- Select a digit pattern that is defined by red-green variation and is easier to see than the pattern defined by yellow-blue variation. (webexhibits.org)
- Observers with red-green deficiency will not be able to see the red-green pattern and base their response only on the yellow-blue pattern. (webexhibits.org)
- The observer pattern is a design pattern that defines a link between objects so that when one object's state changes, all dependent objects are updated automatically. (blackwasp.co.uk)
- What is the Observer Pattern? (blackwasp.co.uk)
- The observer pattern is a Gang of Four design pattern . (blackwasp.co.uk)
- The observer pattern is used to allow a single object, known as the subject , to publish changes to its state. (blackwasp.co.uk)
- The pattern gives loose coupling between the subject and its observers. (blackwasp.co.uk)
- A variation upon the observer pattern is seen in the .NET framework's event model. (blackwasp.co.uk)
- The observer pattern is also used widely in user interface development, particularly with data binding functionality. (blackwasp.co.uk)
- The UML class diagram above describes an implementation of the observer design pattern. (blackwasp.co.uk)
- The following shows the basic code of the observer design pattern implemented using C# . (blackwasp.co.uk)
Unknown4
- On 1895 Sep 07 an unknown observer (Lewis Swift? (aber.ac.uk)
- As the functionality of the observers is unknown, the concrete subjects also provide the means for the observers to read the updated state, in this case via a GetState method. (blackwasp.co.uk)
- Once the variations are identified one must determine for each variation if it has been reported previously and has a known consequence, if it has not been reported previously but would be likely to contribute to a clinical phenotype based on the type of mutation and the gene in which it resides, or if the significance of the mutation is completely unknown. (mlo-online.com)
- If these attempts to characterize the potential impact of a variation fail, then you are left with a variation of unknown clinical significance (VUS)-the black box of genetic sequencing. (mlo-online.com)
Widely1
- Objectives: The investigation of morphological variation in animals is widely used in taxonomy, ecology, and evolution. (researchgate.net)
Ecology1
- The wide geographic variation in the ecology and behavior of vectors, pathogens, reservoirs, and persons is likely to cause corresponding variation in cost-effectiveness of control measures ( 16 ). (cdc.gov)
Findings2
- The findings suggest that a graduated measure is useful for assessing the degree of uncertainty of the observers and subtle effects of different factors upon the judgment of patient's pain. (researchgate.net)
- To make sense of these findings, it is important to remember that most observers think that the Census of Fatal Occupational Injuries (CFOI) provides a good count of traumatic occupational deaths, while there are many concerns about underreporting in the Survey of Occupational Injuries and Illnesses (SOII). (cdc.gov)
Correlation1
- If a clinical phenotype is inherited in a family, correlation of the presence of a given genetic variation in affected family members and not in unaffected family members may also provide evidence supporting the likelihood of the variation's role in the phenotype. (mlo-online.com)
Data3
- The actual functionality of the observers and their use of the state data need not be known by the subject. (blackwasp.co.uk)
- Whole exome sequencing (WES) provides sequencing data and identification of variations in the exons of an individual. (mlo-online.com)
- Whole genome sequencing (WGS) provides sequencing data on both introns and exons and identifies variations in almost all areas of the genome, including regions that may contribute to gene splicing or regulation. (mlo-online.com)
Control2
- We studied monocular OKN in ten observers with early-onset (up to 24 months of age), seven observers with late-onset (after 24 months of age) unilateral strabismus, and 12 normally sighted control observers. (nih.gov)
- The observers in use could be selected by a user at run-time or via a configuration system to allow control of the logger's behaviour without modification to the source code. (blackwasp.co.uk)
Subject4
- Choose a subject below to start exploring Ann Arbor Observer: Then & Now. (aadl.org)
- The subject holds a collection of observers that are set only at run-time. (blackwasp.co.uk)
- It contains a private collection of the observers that are subscribed to a subject and methods to allow new subscriptions to be added and existing ones to be removed. (blackwasp.co.uk)
- When the Update method for an observer is called, it examines the subject to determine which information has changed. (blackwasp.co.uk)
Types1
- Inter-teacher agreement, and some types of teacher-observer agreement, showed significant variation across informant pairs. (umass.edu)
Found2
- Several reports on monocular optokinetic nystagmus (OKN) in observers with strabismus have found that asymmetry of OKN tends to occur in both eyes of observers with an early onset of strabismus but only in the deviating eye of those with a later onset of strabismus. (nih.gov)
- In general, teacher-observer agreement has been found to be superior to parent-teacher agreement, but inferior to inter-teacher agreement. (umass.edu)
Area1
- Inter-observer variances were 0.004 +/- 0.009 mm2 for cup area, 0.008 +/- 0.013 mm2 for disc area and 0.009 +/- 0.014 mm2 for rim area. (nih.gov)
Previously2
Monthly1
- Minor monthly variations in regional activity are typical," he said. (observer.com)
Title1
- The song bears a resemblance to the Shaker song "Simple Gifts" hence the "(Variations on a Shaker Hymn)" in the title. (wikipedia.org)
Piece1
- But, like it or not, it's the topic that shines forth from Paul Hayward's Observer piece on Barcelona yesterday. (runofplay.com)
Effect1
- If ejecta is directed in the line of sight for an observer on Earth, this has the effect of dimming the light received from the star. (britastro.org)
Reports1
- Agreement between teacher reports was stronger than teacher-observer agreement. (umass.edu)
Left1
- then, if the true amplitude be to the right hand of the magnetic, the variation is east, but if to the left hand, it is west. (google.com)
Patients1
- This article presents two experiments aiming to investigate the adoption of a graduated measure to describe credibility attribution by observers who evaluate patients' pain accounts. (researchgate.net)