significant underestimation
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2021 ◽  
Vol 2/2021 (4) ◽  
pp. 68-83
Author(s):  
Sergiusz Łuczak ◽  
Wioletta Jachym

The aim of the article is to analyze the quality of information contained in the bibliographic databases Web of Science and Scopus. The results of the presented study prove that due to errors existing in the analyzed databases, there are often cases of significant underestimation of bibliometric parameters. In extreme cases, the relative error of a given parameter exceeds several dozen per cent, which concerns both individual authors and entire scientific journals. The publication presents a discussion on sources of errors in bibliographic databases and methods of their effective search and correction.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260042
Author(s):  
Adrian Furnham ◽  
Jan Ketil Arnulf ◽  
Charlotte Robinson

This study was concerned with how accurate people are in their knowledge of population norms and statistics concerning such things as the economic, health and religious status of a nation and how those estimates are related to their own demography (e.g age, sex), ideology (political and religious beliefs) and intelligence. Just over 600 adults were asked to make 25 population estimates for Great Britain, including religious (church/mosque attendance) and economic (income, state benefits, car/house ownership) factors as well as estimates like the number of gay people, immigrants, smokers etc. They were reasonably accurate for things like car ownership, criminal record, vegetarianism and voting but seriously overestimated numbers related to minorities such as the prevalence of gay people, muslims and people not born in the UK. Conversely there was a significant underestimation of people receiving state benefits, having a criminal record or a private health insurance. Correlations between select variables and magnitude and absolute accuracy showed religiousness and IQ most significant correlates. Religious people were less, and intelligent people more, accurate in their estimates. A factor analysis of the estimates revealed five interpretable factors. Regressions were calculated onto these factors and showed how these individual differences accounted for as much as 14% of the variance. Implications and limitations are acknowledged.


2021 ◽  
Vol 10 (22) ◽  
pp. 5290
Author(s):  
Maria Luz Servato ◽  
Gisela Teixidó-Turá ◽  
Anna Sabate-Rotes ◽  
Laura Galian-Gay ◽  
Laura Gutiérrez ◽  
...  

Ascending aorta diameters have important clinical value in the diagnosis, follow-up, and surgical indication of many aortic diseases. However, there is no uniformity among experts regarding ascending aorta diameter quantification by echocardiography. The aim of this study was to compare maximum aortic root and ascending aorta diameters determined by the diastolic leading edge (DLE) and the systolic inner edge (SIE) conventions in adult and pediatric patients with inherited cardiovascular diseases. Transthoracic echocardiograms were performed in 328 consecutive patients (260 adults and 68 children). Aorta diameters were measured twice at the root and ascending aorta by the DLE convention following the 2015 American Society of Echocardiography (ASE) adult guidelines and the SIE convention following the 2010 ASE pediatric guidelines. Comparison of the diameters measured by the two conventions in the overall population showed a non-significant underestimation of the diameter measured by the SIE convention at root level of 0.28 mm (CI -1.36; 1.93) and at tubular ascending aorta level of 0.17 mm (CI-1.69; 2.03). Intraobserver and interobserver variability were excellent. Maximum aorta diameter measured by the leading edge convention in end-diastole and the inner edge convention in mid-systole had similar values to a mild non-significant underestimation of the inner-to-inner method that permits them to be interchangeable when used in clinical practice.


2021 ◽  
Author(s):  
Anton Vasilievich Glotov ◽  
Anton Gennadyevich Skripkin ◽  
Petr Borisovich Molokov ◽  
Nikolay Nilovich Mikhailov

Abstract The article presents a new method of determining the residual water saturation of the Bazhenov Rock Formation using synchronous thermal analysis which is combined with gas IR and MS spectroscopy. The efficiency of the extraction-distillation method of determining open porous and residual saturation in comparison with the developed method which are considered in detail. Based on the results of studies in the properties of the Bazhenov Rock Formation, a significant underestimation of the residual water saturation in the existing guidelines for calculating reserves was found, and the structure of the saturation of rocks occurred to be typical for traditional low-permeability reservoirs. The values of open porous and residual water saturation along the section of the Bazhenov Formation vary greatly, which also contradicts the well-established opinion about the weak variability of the rock properties with depth.


2021 ◽  
Author(s):  
Misun Kim ◽  
Christian F Doeller

Terrains in a 3D world can be undulating. Yet, most prior research has exclusively investigated spatial representations on a flat surface, leaving a 2D cognitive map as the dominant model in the field. Here, we investigated whether humans represent a curved surface by building a dimension-reduced flattened 2D map or a full 3D map. Participants learned the location of objects positioned on a flat and curved surface in a virtual environment by driving on the surface (Experiment 1), driving and looking vertically (Experiment 2), or flying (Experiment 3). Subsequently, they were asked to retrieve either the path distance or the 3D Euclidean distance between the objects. Path distance estimation was good overall, but we found a significant underestimation bias for the path distance on the curve, suggesting an influence of potential 3D shortcuts, even though participants were only driving on the surface. Euclidean distance estimation was better when participants were exposed more to the global 3D structure of the environment by looking and flying. These results suggest that the representation of the 2D manifold, embedded in a 3D world, is neither purely 2D nor 3D. Rather, it is flexible and dependent on the behavioral experience and demand.


2021 ◽  
Vol 1043 ◽  
pp. 155-162
Author(s):  
Sergey Georgiev ◽  
Dmitriy Mailyan ◽  
Alik Blyagoz

The article presents the studies’ results on the deformability and strength of reinforced concrete racks reinforced with composite materials with the characteristics stretching beyond the limits established by the norms of Russia, namely: the λh structures flexibility exceeding the value 15, the ratio of the cross-section sides equal to 1.5 and the eccentricity of the load application e0 exceeding 0.1h. The results of the tested racks calculations are analyzed according to BC 164.1325800.2014, which in some cases confirmed the inexpediency of using composite materials. However, according to the results of our experiment, an increase in the strength of a number of racks with the characteristics that go beyond the recommended standards was found. The purpose of this study is to check the methodology for calculating Russian norms for the compressed reinforced concrete elements, the parameters of which are outside the limits recommended by the norms, to develop proposals for improving the calculation based on the obtained experimental data and to determine the concrete deformability effect on the change in bearing capacity. The article discusses flexible struts, reinforced with composite materials, located in the transverse direction. The experimental data results on the deformability of concrete and the strength of struts reinforced in the transverse direction are presented. The calculation methodology, compiled in accordance with Russian standards, the calculation results of which are the theoretical values ​​of the deformability of concrete and the strength of the racks, is considered. After comparison, a significant underestimation of the theoretical strengths and a mismatch in the struts’ concrete deformations were revealed. It was found that the change in compressive deformations of concrete depends on the external composite reinforcement. Theoretical values , calculated according to the current standards, have significant discrepancies with the experimental ones. Based on the experiments’ results analysis, in the methodology of norms for calculating the ultimate compressive deformations of concrete the suggestions that take into account the type and percentage of composite reinforcement and ensure a good agreement between experimental and theoretical values have been made. After the introduction of the coefficient into normative calculation, new data on the theoretical strength of the struts were obtained, which showed significantly better convergence with the experimental data.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hailing Jia ◽  
Xiaoyan Ma ◽  
Fangqun Yu ◽  
Johannes Quaas

AbstractSatellite-based estimates of radiative forcing by aerosol–cloud interactions (RFaci) are consistently smaller than those from global models, hampering accurate projections of future climate change. Here we show that the discrepancy can be substantially reduced by correcting sampling biases induced by inherent limitations of satellite measurements, which tend to artificially discard the clouds with high cloud fraction. Those missed clouds exert a stronger cooling effect, and are more sensitive to aerosol perturbations. By accounting for the sampling biases, the magnitude of RFaci (from −0.38 to −0.59 W m−2) increases by 55 % globally (133 % over land and 33 % over ocean). Notably, the RFaci further increases to −1.09 W m−2 when switching total aerosol optical depth (AOD) to fine-mode AOD that is a better proxy for CCN than AOD. In contrast to previous weak satellite-based RFaci, the improved one substantially increases (especially over land), resolving a major difference with models.


2021 ◽  
Vol 8 ◽  
Author(s):  
Hector Lobeto ◽  
Melisa Menendez ◽  
Iñigo J. Losada

Based on a novel approach, present-day and future spectral wind-wave conditions in a high-emission scenario from a seven-member wave climate projection ensemble are compared. The spectral analysis at the selected locations aids in understanding the propagation of swell projected changes from the generation areas across the ocean basins. For example, a projected increase in the energy from Southern Ocean swells can be observed in all ocean basins and both hemispheres, which is especially relevant in the west coast of North America due to the penetration of these swells beyond 30°N. Similarly, a consistent decrease in the energy of large northern Atlantic swells is noted close to the equator. This work provides evidence that assessments based on only integrated wave parameters (e.g., significant wave height and mean wave period) can mask information about the sign, magnitude, and robustness of the actual wave climate changes due to the offset of positive and negative variations within the spectrum, leading to a significant underestimation of the change associated with certain wave systems.


2021 ◽  
Author(s):  
Logan Bussey ◽  
Srdjan Jelacic ◽  
Kei Togashi ◽  
Andrew Bowdle

AbstractBackgroundQuantitative twitch monitoring is recommended for avoiding residual neuromuscular blockade. Electromyograph twitch monitors are a form of quantitative twitch monitoring. The TwitchView electromyograph has been previously validated against “gold standard” mechanomyography, and may serve as a comparator for other monitors. We have previously shown that the GE electromyograph monitor overcounted twitches, frequently misinterpreting noise as a twitch. This is a pilot study to evaluate the performance of the TetraGraph electromyograph in comparison to the TwitchView electromyograph.MethodsTwitchView and TetraGraph electrodes were applied to opposite arms of patients prior to induction of anesthesia. Post-tetanic count, train-of-four count and train-of-four ratio were then measured approximately every 5 minutes during an unrestricted general anesthetic. Measurements were not made for 10 minutes following neuromuscular blocking drugs or reversal agents.ResultsEight patients were enrolled. The mean baseline train-of-four ratio was 1.02 (SD=0.04) for the TwitchView and 0.99 (SD=0.03) for the TetraGraph (p=0.22). Bland Altman analysis of all of the train-of-four ratio data found that average TwitchView train-of-four values were larger with a bias of 0.10. Train-of-four counts and train-of-four ratios were generally less when measured with TetraGraph than when measured with TwitchView.In 83% (209/253) of data pairs, the result from TetraGraph was less than the result from TwitchView and in 6% (16/253) of data pairs, the result from TetraGraph was greater than the result from TwitchView (p<0.0001). In 11% (28/253) of data pairs, the result from TetraGraph was the same as TwitchView [95%CI 7.35% 16.0%]. Evaluation of individual patient results confirmed the overall results. In some cases there were large discrepancies, such as 4 twitches reported by the TwitchView when the TetraGraph reported a post-tetanic count.ConclusionsUsers of the TetraGraph electromyograph should be aware that significant underestimation of post-tetanic-count, train-of-four count and train-of-four ratio may occur. This could result in administration of unnecessary reversal agents, excessive doses of reversal agents, or delay in extubation. We are undertaking a comparison of the TetraGraph monitor to mechanomyography to confirm the results of this pilot study.


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