bluuebunny/crossref_metadata_2025_split huggingface dataset:
How to detect and reduce potential sources of biases in studies of SARS-CoV-2 and COVID-19
Authors: Accorsi Emma K. , Qiu Xueting , Rumpler Eva , Kennedy-Shaffer Lee , Kahn Rebecca , Joshi Keya , Goldstein Edward , Stensrud Mats J. , Niehus Rene , Cevik Muge , Lipsitch Marc 
Published: February 2021

AbstractIn response to the coronavirus disease (COVID-19) pandemic, public health scientists have produced a large and rapidly expanding body of literature that aims to answer critical questions, such as the proportion of the population in a geographic area that has been infected; the transmissibility of the virus and factors associated with high infectiousness or susceptibility to infection; which groups are the most at risk of infection, morbidity and mortality; and the degree to which antibodies confer protection to re-infection. Observational studies are subject to a number of different biases, including confounding, selection bias, and measurement error, that may threaten their validity or influence the interpretation of their results. To assist in the critical evaluation of a vast body of literature and contribute to future study design, we outline and propose solutions to biases that can occur across different categories of observational studies of COVID-19. We consider potential biases that could occur in five categories of studies: (1) cross-sectional seroprevalence, (2) longitudinal seroprotection, (3) risk factor studies to inform interventions, (4) studies to estimate the secondary attack rate, and (5) studies that use secondary attack rates to make inferences about infectiousness and susceptibility.
Primary Physical Science for Student Teachers at Kindergarten and Primary School Levels: Part II—Implementation and Evaluation of a Course
Authors: Corni Federico , Fuchs Hans U. 
Published: February 2021

AbstractThis is the second of two papers on a novel physical science course for student teachers that develops and uses an imaginative approach to Primary Physical Science Education. General philosophical, cognitive, developmental, and scientific issues have been presented in the first paper; here, we briefly recapitulate the most important aspects. In the main part of the current paper, we present in some detail concrete elements of the implementation of the course at three Italian universities where Primary Physical Science Education has been taught for more than 6 years. After a brief description of the course structure, we discuss which parts of macroscopic physics are taught, and how this is done in lectures and labs. Most importantly, we show how the science is entwined with methods related to pedagogy and didactics that (1) help our students approach the science and (2) can be transferred quite readily to teaching children in kindergarten and primary school. These methods include the design of direct physical experience of forces of nature, embodied simulations, writing and telling of stories of forces of nature, and design and performance of Forces-of-Nature Theater plays. The paper continues with a brief description of feedback from former students who have been teaching for some time, and an in-depth analysis of the research and teaching done by one of the students for her master thesis. We conclude the paper by summarizing aspects of both the philosophy and the design of the course that we believe to be of particular value.
Non-invasive measurement of pulse pressure variation using a finger-cuff method (CNAP system): a validation study in patients having neurosurgery
Authors: Flick Moritz , Hoppe Phillip , Matin Mehr Jasmin , Briesenick Luisa , Kouz Karim , Greiwe Gillis , Fortin Jürgen , Saugel Bernd 
Published: February 2021

AbstractThe finger-cuff system CNAP (CNSystems Medizintechnik, Graz, Austria) allows non-invasive automated measurement of pulse pressure variation (PPVCNAP). We sought to validate the PPVCNAP-algorithm and investigate the agreement between PPVCNAP and arterial catheter-derived manually calculated pulse pressure variation (PPVINV). This was a prospective method comparison study in patients having neurosurgery. PPVINV was the reference method. We applied the PPVCNAP-algorithm to arterial catheter-derived blood pressure waveforms (PPVINV−CNAP) and to CNAP finger-cuff-derived blood pressure waveforms (PPVCNAP). To validate the PPVCNAP-algorithm, we compared PPVINV−CNAP to PPVINV. To investigate the clinical performance of PPVCNAP, we compared PPVCNAP to PPVINV. We used Bland–Altman analysis (absolute agreement), Deming regression, concordance, and Cohen's kappa (predictive agreement for three pulse pressure variation categories). We analyzed 360 measurements from 36 patients. The mean of the differences between PPVINV−CNAP and PPVINV was −0.1% (95% limits of agreement (95%-LoA) −2.5 to 2.3%). Deming regression showed a slope of 0.99 (95% confidence interval (95%-CI) 0.91 to 1.06) and intercept of −0.02 (95%-CI −0.52 to 0.47). The predictive agreement between PPVINV−CNAP and PPVINV was 92% and Cohen’s kappa was 0.79. The mean of the differences between PPVCNAP and PPVINV was −1.0% (95%-LoA−6.3 to 4.3%). Deming regression showed a slope of 0.85 (95%-CI 0.78 to 0.91) and intercept of 0.10 (95%-CI −0.34 to 0.55). The predictive agreement between PPVCNAP and PPVINV was 82% and Cohen’s kappa was 0.48. The PPVCNAP-algorithm reliably calculates pulse pressure variation compared to manual offline pulse pressure variation calculation when applied on the same arterial blood pressure waveform. The absolute and predictive agreement between PPVCNAP and PPVINV are moderate.
The Return-to-Work Self-efficacy Questionnaire (RTW-SE): A Validation Study of Predictive Abilities and Cut-off Values for Patients on Sick Leave Due to Anxiety or Depression
Authors: Gjengedal Ragne G. H. , Lagerveld Suzanne E. , Reme Silje E. , Osnes Kåre , Sandin Kenneth , Hjemdal Odin 
Published: February 2021

AbstractPurpose This study aimed to evaluate the validity of the Return-to-Work Self-efficacy Questionnaire (RTW-SE) in a Norwegian sample of patients with common mental disorders. The secondary aim was to provide validated cut-off scores for the RTW-SE. Methods Among patients receiving work-focused therapy (N = 626), the RTW-SE was measured pre-and post-treatment, and work status was assessed up to one-year post-treatment. The factor structure, internal consistency and construct validity were assessed. Furthermore, post-treatment cut-off scores were calculated using receiver operating characteristic (ROC) analysis for patients on sick leave at baseline (n = 314) and at the end of treatment (n = 145). The predictive ability of the suggested RTW-SE cut-off scores were investigated longitudinally. Results Exploratory principal component analysis identified a one-factor solution with high internal consistency (0.91). RTW-SE exhibited small to moderate negative correlations with measures of depression and anxiety, and was significantly different between subgroups of patients with different work status, supporting construct validity. Pre- and post-treatment RTW-SE scores significantly predicted full return to work at 3, 6 and 12 months post-treatment. ROC analysis suggested an upper cut-off score of 4.6, associated with full RTW, and lower cut-off score of 3.7, associated with partial RTW. These cut-offs showed acceptable discriminative ability and significant longitudinal predictive ability. Conclusion The RTW-SE possesses good psychometric properties and the suggested cut-off scores have significant predictive ability in a clinical setting.
Assessment of 232Th, 226Ra, 137Cs, and 40 K concentrations and annual effective dose due to the consumption of Vietnamese fresh milk
Authors: Duong Van-Hao , Nguyen Thanh-Duong , Hegedűs Miklós , Tóth-Bodrogi Edit , Kovács Tibor 
Published: February 2021

AbstractVietnam has little data on radionuclide concentrations in milk, despite steadily increasing domestic consumption. Eight milk brands were investigated by gamma-spectrometry, and the resulting ingestion dose was calculated. The 232Th, 226Ra, 137Cs, and 40K concentrations varied from 0.60 ± 0.19 to 1.21 ± 0.24, 1.45 ± 0.18 to 2.45 ± 0.24, below detection limit to 0.13 ± 0.06, and 341 ± 6 to 387 ± 7 Bq/kg (dry w.t). The total average Annual Effective Dose for all age groups were similar for all brands, and concentrations are far less than the WHO guidance level. All brands are safe for consumption.
Vacuum versus ambient pressure inert gas thermogravimetry: a study of silver carboxylates
Authors: Jurczyk Jakub , Glessi Cristiano , Madajska Katarzyna , Berger Luisa , Nyrud Jeroen Ingolf Ketele , Szymańska Iwona , Kapusta Czesław , Tilset Mats , Utke Ivo 
Published: February 2021

AbstractA comparative study of vacuum versus ambient pressure inert gas thermogravimetry was performed on silver carboxylates compounds. Some of the complexes from this group have been previously successfully applied as precursors for both chemical vapour deposition and electron beam-induced deposition. Considerable differences were found between the thermogravimetry methods, which we associate with changes in evaporation dynamics. Vacuum thermogravimetry sublimation onsets consistently occurred at lower temperatures than ambient pressure N2-flow thermogravimetry, where the differences reached up to 120 °C. Furthermore, compound sublimation during N2-TGA was suppressed to such an extent that significant thermal decomposition of the compounds into metal and volatile organic fragments was observed while at vacuum the same complexes sublimed as intact molecules. Moreover, thermal stability of silver complexes was investigated using isothermal thermogravimetry. These findings are interesting for the field of thin film synthesis and nanomanufacturing via chemical vapour deposition, atomic layer deposition and focused electron beam induced deposition. In all three methods, delivery of functional precursor over the substrate is crucial. The presented results prove that vacuum thermogravimetry can be used as fast method of pre-screening for novel, especially low-volatility precursors.
Graphic abstract
The gas evolution of a modified cellulose mixture used for gating systems in the no-bake mould process
Authors: Zawieja Zbigniew , Sawicki Jacek 
Published: February 2021

AbstractThis paper shows the results of a study of gas evolution from a patented modified cellulose mix used in the production of no-bake casting moulds. The modified cellulose mixture was used for investigation with additives such as expanded perlite, expanded vermiculite and microspheres. The binder was an inorganic resin based on commercial technology, called Geopol. Samples were tested in different compositions in order to show the influence of all the additives mentioned. Two different methods were used—one was based on TG–TDG–MS investigation and the other was based on pyrolysis combined with a gas composition analyser. Investigations of both methods were carried out at temperatures up to 900 °C. The results showed that the gas emissions during thermal degradation of all the modified mixtures did not constitute substances that are hazardous or dangerous to health. Therefore, the material proposed can be used as a solution that is more environmentally friendly when compared to formulas which exist on the market and are abundant in harmful compounds.
Information measures and design issues in the study of mortality deceleration: findings for the gamma-Gompertz model
Authors: Böhnstedt Marie , Gampe Jutta , Putter Hein 
Published: February 2021

AbstractMortality deceleration, or the slowing down of death rates at old ages, has been repeatedly investigated, but empirical studies of this phenomenon have produced mixed results. The scarcity of observations at the oldest ages complicates the statistical assessment of mortality deceleration, even in the parsimonious parametric framework of the gamma-Gompertz model considered here. The need for thorough verification of the ages at death can further limit the available data. As logistical constraints may only allow to validate survivors beyond a certain (high) age, samples may be restricted to a certain age range. If we can quantify the effects of the sample size and the age range on the assessment of mortality deceleration, we can make recommendations for study design. For that purpose, we propose applying the concept of the Fisher information and ideas from the theory of optimal design. We compute the Fisher information matrix in the gamma-Gompertz model, and derive information measures for comparing the performance of different study designs. We then discuss interpretations of these measures. The special case in which the frailty variance takes the value of zero and lies on the boundary of the parameter space is given particular attention. The changes in information related to varying sample sizes or age ranges are investigated for specific scenarios. The Fisher information also allows us to study the power of a likelihood ratio test to detect mortality deceleration depending on the study design. We illustrate these methods with a study of mortality among late nineteenth-century French-Canadian birth cohorts.
Factor Structure and Equivalence of Maternal Resources for Care in Bangladesh, Vietnam, and Ethiopia
Authors: Basnet Sulochana , Frongillo Edward A. , Nguyen Phuong Hong , Moore Spencer , Arabi Mandana 
Published: February 2021

AbstractObjectivesResources for care among women are crucial for children’s growth and development. The objectives of this cross-sectional study were to determine if: (1) the factor structure of measures of maternal resources for care was comparable across countries and consistent with the theoretical constructs and (2) the measures showed equivalence across contexts.MethodsThe study included 4400, 4029 and 2746 women from Bangladesh, Vietnam, and Ethiopia, respectively. The measures of resources for care were maternal education, knowledge, height, body mass index, mental well-being, financial autonomy, decision-making, employment, support in chores, and perceived support.ResultsThe factor analysis demonstrated that a two-factor solution best explained the structure of resources for care in all three countries. The first factor was associated with financial autonomy and employment in all three countries and with decision-making in two countries. The second factor was associated with education and knowledge in all three countries. The measures of resources for care had measurement equivalence across countries.Conclusion for PracticeResources for care were structurally similar and measurement equivalent across countries and can be used for measurement in low- and middle-income countries. Additional work examining the structure and cross-context equivalence of resources for care in other settings is warranted.
Leveraging circuit theory and nonlinear dynamics for the efficiency improvement of energy harvesting
Authors: Bonnin Michele , Traversa Fabio L. , Bonani Fabrizio 
Published: February 2021

AbstractWe study the performance of vibrational energy harvesting systems with piezoelectric and magnetic inductive transducers, assuming the power of external disturbance concentrated around a specific frequency. Both linear and nonlinear harvester models are considered. We use circuit theory and equivalent circuits to show that a large improvement in both the harvested energy and the power efficiency is obtained, for linear systems, through a proper reactive modification of the load. For nonlinear systems, we use methods of nonlinear dynamics to derive analytical formulae for the output voltage, the harvested energy and the power efficiency. We show that also for the nonlinear case, the modified load significantly boosts the performance.
Tracking developments in artificial intelligence research: constructing and applying a new search strategy
Authors: Liu Na , Shapira Philip , Yue Xiaoxu 
Published: February 2021

AbstractArtificial intelligence, as an emerging and multidisciplinary domain of research and innovation, has attracted growing attention in recent years. Delineating the domain composition of artificial intelligence is central to profiling and tracking its development and trajectories. This paper puts forward a bibliometric definition for artificial intelligence which can be readily applied, including by researchers, managers, and policy analysts. Our approach starts with benchmark records of artificial intelligence captured by using a core keyword and specialized journal search. We then extract candidate terms from high frequency keywords of benchmark records, refine keywords and complement with the subject category “artificial intelligence”. We assess our search approach by comparing it with other three recent search strategies of artificial intelligence, using a common source of articles from the Web of Science. Using this source, we then profile patterns of growth and international diffusion of scientific research in artificial intelligence in recent years, identify top research sponsors in funding artificial intelligence and demonstrate how diverse disciplines contribute to the multidisciplinary development of artificial intelligence. We conclude with implications for search strategy development and suggestions of lines for further research.
Factors affecting the citations of papers in tribology journals
Authors: Liskiewicz T. , Liskiewicz G. , Paczesny J. 
Published: February 2021

AbstractThe citations count is flawed but it still the most common way of measuring the academic impact used by scholarly journals (Impact Factor), individual researchers (h-index) and funding agencies (a proxy for quality of research). Individual papers should attract citations depending upon the importance and usefulness of the results presented. However, large enough data sets reveal that there are parameters independent of individual papers' quality that can determine an average citation rate. Here, we examine papers (4756 in total) published in six selected tribology journals in a six-year window between January 2010 and December 2015. Citations were retrieved from the Web of Science and compared with their (1) manuscript length, (2) number of authors, (3) number of affiliated institutions, (4) number of international co-authors, (5) number of cited references, (6) number of words in the title, and (7) mode of publication (open versus paid access). The results revealed that citations received by papers published in tribology journals are affected by all of these parameters. This is a significant finding for authors wishing to increase the impact of their research. This knowledge can be used effectively at the manuscript planning and writing stages to support scientific merit. We suggest that the significance of parameters not directly related to the quality of a scholarly paper will become more critical with the rise of alternative ways of measuring impact including novel generation of paper metrics (e.g., Eigenfactor, SJR), social mentions, and viral outreach.
Journal rankings and publication strategy
Authors: Śpiewanowski Piotr , Talavera Oleksandr 
Published: February 2021

AbstractWe study the impact of journal ranking systems on publication outlet choice. We investigate the publication behavior of UK-based scholars registered on IDEAS/RePEc and analyze the publication outcomes of their academic work uploaded to the repository. Our estimates suggest that authors strategically choose outlets to maximize their publication scores. Our identification strategy is based on exploiting the change in the British ABS journal ranking in 2015. Working papers written before the 2015 ABS journal ranking change are significantly less likely to be published in ex-post downgraded journals. The effect cannot be attributed to the overall change in journal quality.
Specification testing in semi-parametric transformation models
Authors: Kloodt Nick , Neumeyer Natalie , Van Keilegom Ingrid 
Published: February 2021

AbstractIn transformation regression models, the response is transformed before fitting a regression model to covariates and transformed response. We assume such a model where the errors are independent from the covariates and the regression function is modeled nonparametrically. We suggest a test for goodness-of-fit of a parametric transformation class based on a distance between a nonparametric transformation estimator and the parametric class. We present asymptotic theory under the null hypothesis of validity of the semi-parametric model and under local alternatives. A bootstrap algorithm is suggested in order to apply the test. We also consider relevant hypotheses to distinguish between large and small distances of the parametric transformation class to the ‘true’ transformation.
Adsorption and Surface Diffusion of Metals on α-Al2O3 for Advanced Manufacturing Applications
Authors: Biaggne Austin , Noble Gregory , Li Lan 
Published: February 2021

AbstractThe adsorption and diffusion of Mo and Nb adatoms on the $$\alpha$$
α
-Al2O3 (0001) surface were explored using density functional theory-based methods. Adsorption energies of Mo and Nb adatoms at minima sites on the surface were determined. Mo and Nb adatoms prefer to adsorb to the same locations on the surface, and larger adsorption energies calculated for Nb compared to Mo indicate that Nb adatom-surface interactions are stronger than Mo. Using minima adsorption sites as initial and final locations for surface diffusion, energy barriers for diffusion were calculated using the nudged elastic band method. Overall, Mo and Nb follow roughly the same diffusion paths. The diffusion pre-factors for Mo and Nb are similar; however, Mo diffusion has a lower energy barrier and thus a larger diffusion coefficient compared with Nb. These results provide insight into the role of surface diffusion of Mo and Nb adatoms during advanced manufacturing processes.
Patient profiles as an aim to optimize selection in the second line setting: the role of aflibercept
Authors: González Astorga B. , Salvà Ballabrera F. , Aranda Aguilar E. , Élez Fernández E. , García-Alfonso P. , González Flores E. , Vera García R. , Fernández Montes A. , López Muñoz A. M. , Salud Salvia A. 
Published: February 2021

AbstractColorectal cancer is the second leading cause of cancer-related death worldwide. For metastatic colorectal cancer (mCRC) patients, it is recommended, as first-line treatment, chemotherapy (CT) based on doublet cytotoxic combinations of fluorouracil, leucovorin, and irinotecan (FOLFIRI) and fluorouracil, leucovorin, and oxaliplatin (FOLFOX). In addition to CT, biological (targeted agents) are indicated in the first-line treatment, unless contraindicated. In this context, most of mCRC patients are likely to progress and to change from first line to second line treatment when they develop resistance to first-line treatment options. It is in this second line setting where Aflibercept offers an alternative and effective therapeutic option, thought its specific mechanism of action for different patient’s profile: RAS mutant, RAS wild-type (wt), BRAF mutant, potentially resectable and elderly patients. In this paper, a panel of experienced oncologists specialized in the management of mCRC experts have reviewed and selected scientific evidence focused on Aflibercept as an alternative treatment.