bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Na‐PDT and KF‐PDT on the photovoltaic performance of wide bandgap Cu (In,Ga)Se2 solar cells
Authors: Zahedi‐Azad Setareh , Maiberg Matthias , Scheer Roland
Published: August 2020

Cu (In,Ga)Se2 solar cells exhibit higher efficiencies if an appropriate Ga gradient is introduced and if the absorber is doped with sodium (Na) plus a heavier alkali atom such as potassium. However, a Gallium gradient in the presence of Na is challenging because sodium impedes the interdiffusion of elements and influences the gradient. In this contribution, we show that the presence of sodium during growth with the combination of high Ga concentration creates a pronounced gradient that is detrimental for carrier collection. One solution is to avoid Na abundance during absorber growth but to add it to the grown absorber layer via a postdeposition treatment. We investigate the effect of different Na incorporation methods simultaneously with KF‐PDT on wide band gap CIGSe absorbers. By preparation on alkali‐free substrates and application of alkalis (NaF and KF) onto a grown CIGSe layer, we show by smoothening of the Gallium gradient a large improvement in the solar cell performance from 4% to 8%. Another way to optimize the gradient in the presence of Na is the modification of the three‐stage method. This yields the best efficiency of 10% in our laboratory at an integral GGI of ~0.8. By means of temperature‐dependent JV measurements, we show that the additional postdeposition of KF induces a barrier for the diode current. We conclude that KF‐PDT induces a new thin layer at the CIGSe surface that has a lower valence band edge relative to the CIGSe bulk and is responsible for the double‐diode behavior. This barrier can also explain the Voc(T) saturation at low temperature.
Safe reinforcement learning: A control barrier function optimization approach
Authors: Marvi Zahra , Kiumarsi Bahare
Published: August 2020

This article presents a learning‐based barrier certified method to learn safe optimal controllers that guarantee operation of safety‐critical systems within their safe regions while providing an optimal performance. The cost function that encodes the designer's objectives is augmented with a control barrier function (CBF) to ensure safety and optimality. A damping coefficient is incorporated into the CBF which specifies the trade‐off between safety and optimality. The proposed formulation provides a look‐ahead and proactive safety planning and results in a smooth transition of states within the feasible set. That is, instead of applying an optimal controller and intervening with it only if the safety constraints are violated, the safety is planned and optimized along with the performance to minimize the intervention with the optimal controller. It is shown that addition of the CBF into the cost function does not affect the stability and optimality of the designed controller within the safe region. This formulation enables us to find the optimal safe solution iteratively. An off‐policy reinforcement learning (RL) algorithm is then employed to find a safe optimal policy without requiring the complete knowledge about the system dynamics, while satisfies the safety constraints. The efficacy of the proposed safe RL control design approach is demonstrated on the lane keeping as an automotive control problem.
Assessing the potential for spectrally based remote sensing of salmon spawning locations
Authors: Harrison Lee R. , Legleiter Carl J. , Overstreet Brandon T. , Bell Tom W. , Hannon John
Published: August 2020

Remote sensing tools are increasingly used for quantitative mapping of fluvial habitats, yet few techniques exist for continuous sampling of aquatic organisms, such as spawning salmonids. This study assessed the potential for spectrally based remote sensing of salmon spawning locations (i.e., redds) using data acquired from unmanned aircraft systems (UAS) along a large, gravel‐bed river. We developed a novel, semi‐automated approach for detecting salmon redds by applying machine learning classification and object detection techniques to UAS‐based imagery. We found that both true colour (RGB) and hyperspectral imagery could be used to identify salmon redds, though with varying degrees of accuracy. Redds were mapped with accuracies of ~0.75 from RGB imagery using logistic regression and support vector machines (SVM) classification algorithms, but this type of data could not be used to identify redds using Object‐based Image Analysis (OBIA). The hyperspectral imagery was more useful for mapping salmon redds, with accuracies greater than 0.9 for both logistic regression and SVM classifiers; OBIA of the hyperspectral data resulted in redd detection accuracies up to 0.86. The hyperspectral imagery also yielded complementary physical habitat information including water depth and substrate composition, which we quantified on the basis of a spectrally based chlorophyll absorption ratio. Overall, the hyperspectral imagery more effectively identified salmon spawning locations than RGB images and was more conducive to the classification approaches we evaluated. Each type of remotely sensed data had advantages and limitations, which are important for potential users to understand when incorporating UAS‐based data collection into river ecosystem studies.
Chiral Oxazolinyl Hydroxyl Ferrocene Catalysts: Synthesis and Applications in Asymmetric Reactions
Authors: Xu Di , Zhang Jun , Dai Li
Published: August 2020

Chiral oxazolinyl hydroxyl ferrocenes have been demonstrated as representative catalysts in enantioselective nucleophilic addition reactions in the last few decades. They have received much interest from chemists because of not only the numerous substitution patterns at their sandwich backbones, but also their superior catalytic activity in asymmetric transformations. Recent research has revealed that the planar chirality of these catalysts influences the stereochemistry of asymmetric products and the application scope in enantioselective reactions. Herein, we provide an intensive survey of chiral oxazolinyl hydroxyl ferrocene compounds, including the structures of chiral compounds already published, designed synthetic approaches for ferrocenes with different patterns, and their utilization in the enantioselective preparation of secondary alcohols using organozinc reagents.
The FeN3 Doped Fluorographene for N2 Fixation: A Density Functional Theory Study
Authors: Yang Lei , Yu Li‐Bing , Liu Shuai‐Shuai , Song Er‐Hong , Song Yin‐Dong , Xiao Bei‐Bei
Published: August 2020

The ammonia synthesis under ambient condition is of significance for sustainable energy utilization. Herein, the nitrogen reduction reaction (NRR) on FeN3 embedded graphane and fluorographene are investigated by density functional theory calculations. Our results indicate that the functional fluorographene accelerates electrocatalytic N2 fixation with an onset‐potential of 0.97 V via alternating mechanism, being superior to the graphane counterpart. Furthermore, the fluorination alleviates the H poisoning and increases NRR selectivity. The improved performance is originated from the strong electron‐withdrawing of the F decoration. Moreover, the inferior NRR performance of the FeN3 decorated graphane indicates the infeasibility as the NRR electrode, reasonably avoiding the experimental attempt. This finding opens up the new design for the carbon‐based electrocatalysts with high efficiency of NH3 synthesis.
A Bayesian non‐parametric approach for automatic clustering with feature weighting
Authors: Paul Debolina , Das Swagatam
Published: August 2020

Despite being a well‐known problem, feature weighting and feature selection are a major predicament for clustering. Most of the algorithms, which provide weighting or selection of features, require the number of clusters to be known in advance. On the other hand, the existing automatic clustering procedures that can determine the number of clusters are computationally expensive and often do not make a room for feature weighting or selection. In this paper, we propose a Gibbs sampling‐based algorithm for the Dirichlet process mixture model, which can determine the number of clusters and can also incorporate a near‐optimal feature weighting. We show that in the limiting case, the algorithm approaches a hard clustering procedure, which resembles minimization of an underlying clustering objective similar to weighted k‐means with an additional forfeit for the number of clusters and hence retains the simplicity of the Llyod's heuristics. To avoid the trivial solution of the resulting linear program, we include an additional entropic penalty on the feature weights. The proposed algorithm is tested on several synthetic and real‐life datasets. Through a detailed experimental analysis, we demonstrate the competitiveness of our proposal against the baseline as well as state‐of‐the‐art procedures for centre‐based high‐dimensional clustering.
Ultrasonication Improves the Structures and Physicochemical Properties of Cassava Starch Films Containing Acetic Acid
Authors: Wu Fuqi , Zhou Zeguang , Liang Manling , Zhong Lei , Xie Fengwei
Published: August 2020

Cassava starch films are fabricated with acetic acid treatment and ultrasonication. Different ultrasound power levels from 200 to 750 W are used and the effects of ultrasonication on the morphology, microstructures, and properties of the starch–acetic acid films are investigated. Scanning electron microscopy shows a cohesive and compact structure of the films resulting from ultrasonication. X‐ray diffraction analysis reveals that the crystalline index is decreased by acid treatment and increased by ultrasonication. The tensile strength and elongation at break of the films first increase and then decrease with increasing ultrasound power level. Ultrasonication also results in higher opacity, higher water barrier performance, and lower water adsorption of the films. Thus, the results show that ultrasonication can be used as a simple and efficient way to modify the morphology, microstructure, and performance of starch–acetic acid films to better meet the application needs.
Study on bond strength of geopolymer and control concrete between fiber‐reinforced polymer and steel bars
Authors: Subramanian Nagajothi , Solaiyan Elavenil
Published: August 2020

Significant issue in reinforced concrete (RC) structures is corrosion of steel. High alkalization of cement matrix, low permeability, and sufficient cover plays an important role to shield from corrosion of steel. There is a replacement material for steel is fiber‐reinforced polymer (FRP) bars as reinforcement. The FRP bars are nonconductive and durable material and they are composited from fibers and polymers matrix. In this study, new technology geopolymer concrete (GC) was used along with glass fiber‐reinforced polymer (GFRP) and basalt fiber‐reinforced polymer (BFRP) bars. GC is produced from industrial by‐product materials such as fly ash and ground granulated blast furnace slag (rich in silica and alumina) and treated as sustainable material. The long term durability of many RC structures affects drastically by the reinforcement corrosion. Main aspect of bond behavior is tension stiffening as it has capability to control the reinforcement to shift the tensile stresses to concrete. This paper evaluates the bond strength between the GC reinforced with GFRP/BFRP and the results were evaluated with conventional concrete (CC) reinforced with steel. The pullout test method was used to determine the bond between FRP and steel bars with the surrounding concrete based on IS: 2770 (part I)‐1967. The comparison of bond strength GC with FRP almost same as CC with steel. The tension test and double shear test were also carried out in FRP and steel bars based on IS 432–1982 and 5242–1979, respectively.
An example of harnessing crushed ceramic pots for the production of watertight concrete
Authors: Halbiniak Jacek , Katzer Jacek , Major Maciej , Langier Bogdan , Major Izabela
Published: August 2020

This article presents the results of the research program aimed to analyze the opportunities for using waste ceramic pots for the production of watertight concrete. The mechanically processed crushed ceramic pots were added to the concrete mix in two ways: as a microfiller and as a recycled fine ceramic aggregate. The ceramic meal with a fraction below 0.25 mm was obtained by processing crushed pots using a mill and disintegrator. The pulverized ceramic material was added in 10%, 20%, and 30% of the cement mass. Recycled fine ceramic aggregate with a particle diameter up to 4 mm was created using only industrial mill. The aggregate obtained from pots was used to replace 20%, 30%, and 40% of the sand mass. Altogether, seven different mixes were created. The testing covered following properties: compressive strength, water absorption, and depth of water penetration. Concretes modified with the ceramic meal obtained higher compressive strength, lower water absorption and lower values of depth of water penetration in comparison to reference concrete. Mixes with recycled fine ceramic aggregate were characterized by slightly higher compressive strength in comparison to the reference concrete and similar values of water absorption and depth of water penetration.
Extension of direct displacement‐based design for quantifying higher mode effects on controlled rocking steel cores
Authors: Rahgozar Navid , Rahgozar Nima
Published: August 2020

Direct displacement‐based design (DDBD) procedure utilizes an equivalent single‐degree‐of‐freedom model to predict seismic demands while neglecting the higher mode effects. Controlled rocking steel cores (CRSCs) vibrate in the first mode of vibration; however, higher modes greatly influence the member forces. Previous studies, in which DDBD has been utilized, have not quantified the contribution of higher mode demands to CRSC's assemblies. This paper aims to extend the DDBD (EDDBD) procedure for low‐damage buildings, equipped with CRSCs. Modal responses are combined with modified SRSS at the design displacement. Design is formulated for the strength and stiffness of the CRSC components. The application of the proposed design approach is illustrated by 3‐, 9‐, and 15‐story archetypes. Results verified by nonlinear dynamic analyses demonstrate the high precision of EDDBD in the design of low‐ to mid‐rise CRSCs. The proposed procedure is applicable to commercial software.
Reducing the Alternating Current Resistance and Heat Generation in a Single‐Wire Coil Using a Magnetic Tape
Authors: Sato Mitsuhide , Sugimoto Kaito , Kubota Kazuma , Endo Shun , Mizuno Tsutomu
Published: August 2020

In today's fast‐paced environment, the downsizing of electronic devices has become imperative. A high driving frequency is effective for the downsizing of electronic equipment. However, one problem with high driving frequency is that it increases the ac resistance and heat generation on passive devices. Using a magnetic coating on the copper wire can effectively reduce the ac resistance. In this study, we propose a method for wrapping a magnetic tape around a copper wire to easily provide a uniform magnetic coating for reducing the ac resistance. In the magnetic field simulation, we reduced the proximity effect in the coil by using a magnetic tape. The temperature rise at the thermal saturation was reduced by 26% for the experiment with a high‐frequency current of 4 A. Applying the magnetic tape to a single‐wire coil effectively reduced the ac resistance and heat generation. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
Strategies for visualizing inflammation
Authors: Zhang Xinping , Liu Xiaoyang , Guo Yuxin , Wu Fu‐Gen
Published: August 2020

As a basic innate immune response to the disordered tissue homeostasis, inflammation is related to the pathogenesis of multiple diseases, including bacterial infections, atherosclerosis, neurodegenerative diseases, and cancers. It is also a pivotal feature of some metabolic disorders such as diabetes and obesity. The visualization of in vivo inflammations can help us to comprehend the pathogenesis of these diseases and develop new solutions to diagnose them. Over the past few decades, a variety of strategies (eg, computed tomography, magnetic resonance imaging [MRI], and ultrasound [US] imaging) have been utilized for visualizing inflammations by imaging the structural changes of inflammatory tissues. Moreover, many recent studies have focused on some probes that can target or localize the inflammatory sites by specific binding to inflammation‐related molecules, being internalized by inflammatory cells, or becoming detectable only under inflammatory conditions. These probes can also be applied to visualize inflammations by MRI, positron emission tomography, single‐photon emission computed tomography, photoacoustic imaging, optical imaging (eg, fluorescence imaging, bioluminescence imaging, and chemiluminescence imaging), contrast‐enhanced US imaging, and the combined use of the abovementioned methods. This review not only summarizes the existing strategies for visualizing inflammations, but also discusses the limitations of the present strategies and the future directions on the development of new strategies for realizing the in vivo inflammation visualization.
MPC framework for constrained wind turbine individual pitch control
Authors: Petrović Vlaho , Jelavić Mate , Baotić Mato
Published: August 2020

The reduction of structural loads is becoming an important objective for the wind turbine control system due to the ever‐increasing specifications/demands on wind turbine rated power and related growth of turbine dimensions. Among various control algorithms that have been researched in recent years, the individual pitch control has demonstrated its effectiveness in wind turbine load reduction. Since the individual pitch control, like other load reduction algorithms, requires higher levels of actuator activity, one must take actuator constraints into account when designing the controller. This paper presents a method for the inclusion of such constraints into a predictive wind turbine controller. It is shown that the direct inclusion of constraints would result in a control problem that is nonconvex and difficult to solve. Therefore, a modification of the constraints is proposed that ensures the convexity of the control problem. Simulation results show that the developed predictive control algorithm achieves individual pitch control objectives while satisfying all imposed constraints.
Songbird Use of Native and Invasive Fruit in the Northeastern USA
Authors: Labbé Michelle A. , King David I.
Published: August 2020

Fruit is consumed by songbirds, yet whether or not it comprises an important component of habitat quality depends on the extent to which it is used by birds. In addition, there is evidence fruits of exotic invasive species may be nutritionally inferior to fruits of native species, so the influence of plant invasion on bird body condition is of interest to managers. Birds that consume invasive fruits may also serve as seed vectors, and consumption of fruits of invasive species may exacerbate invasion. Thus, the extent to which songbirds consume fruits of native versus invasive plant species, influence of plant invasion on bird body condition, and extent to which birds exhibit foraging behaviors that elevate their potential to act as dispersers of invasive species have important implications for habitat management. To understand bird use of native and invasive fruits and the potential role of birds in dispersing invasive plants, we observed bird foraging, measured body condition indices of birds captured in mist nets, measured available fruits of native and invasive plants, and calculated indices of seed dispersal for bird species based on fruit handling and consumption, within 16 shrubland sites in western Massachusetts, USA. Our findings indicate that birds use fruit extensively (57% of foraging events), use varied among species, and frugivorous species at our sites generally chose the fruit of native species, especially Prunus, over fruits of invasive species. Body condition indices were negatively related to the proportion of invasive fruit in most cases. In general, birds were better dispersers for native fruits than for invasive fruits. Our findings support the value of native fruit resources as a component of habitat quality, and, conversely, suggest that nonnative plant invasion may lead to reduced habitat quality for songbirds. © 2020 The Wildlife Society.
Strength and stiffness predictions with focus on different acoustic measurement methods
Authors: Kovryga A. , Chuquin Gamarra J. O. , van de Kuilen J. W. G.
Published: August 2020

Strength grading is an important step for the production of homogenous and high-quality solid wood material. In particular, for hardwoods, the use of non-visible characteristics is indispensable. Dynamic MOE (Edyn) is an important parameter widely used for grading of softwoods and applicable to hardwoods as well. There are two common ways to measure Edyn—ultrasound (US) wave propagation and longitudinal vibration (LV) method. Both methods are used in practice, however, due to the different inherent measurement techniques, the results differ. The current paper analyses the stiffness and strength coefficients of determination for several temperate European hardwood species and emphasizes the differences between the two measurement systems. The performance was analysed with regard to grading techniques, testing modes for the mechanical properties (tension and bending) and wood qualities. For more than 2861 pieces of European ash (Fraxinus excelsior), European beech (Fagus sylvatica), European oak (Quercus spp.) and maple (Acer spp.), the Edyn was measured using both techniques, and destructive tests (tension and edgewise bending) were applied. The results show that LV has higher coefficient of determination compared to the US Edyn. The coefficient of determination for both methods and tensile application can be increased by calculating Edyn with average density. Furthermore, the results support species-independent strength grading of hardwoods. Further research on the effect of different wood qualities and sawing patterns is required.
Immersive analysis of user motion in VR applications
Authors: Kloiber Simon , Settgast Volker , Schinko Christoph , Weinzerl Martin , Fritz Johannes , Schreck Tobias , Preiner Reinhold
Published: August 2020

With the rise of virtual reality experiences for applications in entertainment, industry, science and medicine, the evaluation of human motion in immersive environments is becoming more important. By analysing the motion of virtual reality users, design choices and training progress in the virtual environment can be understood and improved. Since the motion is captured in a virtual environment, performing the analysis in the same environment provides a valuable context and guidance for the analysis. We have created a visual analysis system that is designed for immersive visualisation and exploration of human motion data. By combining suitable data mining algorithms with immersive visualisation techniques, we facilitate the reasoning and understanding of the underlying motion. We apply and evaluate this novel approach on a relevant VR application domain to identify and interpret motion patterns in a meaningful way.
The $$h^*$$-Polynomials of Locally Anti-Blocking Lattice Polytopes and Their $$\gamma $$-Positivity
Authors: Ohsugi Hidefumi , Tsuchiya Akiyoshi
Published: August 2020

A lattice polytope$$\mathscr {P} \subset \mathbb {R}^d$$P⊂Rdis called a locally anti-blocking polytope if for any closed orthant$${\mathbb R}^d_{\varepsilon }$$Rεdin$$\mathbb {R}^d$$Rd,$$\mathscr {P} \cap \mathbb {R}^d_{\varepsilon }$$P∩Rεdis unimodularly equivalent to an anti-blocking polytope by reflections of coordinate hyperplanes. We give a formula for the$$h^*$$h∗-polynomials of locally anti-blocking lattice polytopes. In particular, we discuss the$$\gamma $$γ-positivity of$$h^*$$h∗-polynomials of locally anti-blocking reflexive polytopes.
Downscaling daily air-temperature measurements in the Netherlands
Authors: Dirksen Marieke , Knap Wouter H. , Steeneveld Gert-Jan , Holtslag Albert A. M. , Tank Albert M. G. Klein
Published: August 2020

High-resolution, regularly gridded air-temperature maps are frequently used in climatology, hydrology, and ecology. Within the Netherlands, 34 official automatic weather stations (AWSs) are operated by the National Met Service according to World Meteorological Organization (WMO) standards. Although the measurements are of high quality, the spatial density of the AWSs is not sufficient to reconstruct the temperature on a 1-km-resolution grid. Therefore, a new methodology for daily temperature reconstruction from 1990 to 2017 is proposed, using linear regression and multiple adaptive regression splines. The daily 34 AWS measurements are interpolated using eight different predictors: diurnal temperature range, population density, elevation, albedo, solar irradiance, roughness, precipitation, and vegetation index. Results are cross-validated for the AWS locations and compared with independent citizen weather observations. The RMSE of the reference method ordinary kriging amounts to 2.6 °C whereas using the new methods the RMSE drops below 1.0 °C. Especially for cities, a substantial improvement of the predictions is found. Independent predictions are on average 0.3 °C less biased than ordinary kriging at 40 high-quality citizen measurement sites. With this new method, we have improved the representation of local temperature variations within the Netherlands. The temperature maps presented here can have applications in urban heat island studies, local trend analysis, and model evaluation.
Super-stability in the student-project allocation problem with ties
Authors: Olaosebikan Sofiat , Manlove David
Published: August 2020

The Student-Project Allocation problem with lecturer preferences over Students (spa-s) involves assigning students to projects based on student preferences over projects, lecturer preferences over students, and the maximum number of students that each project and lecturer can accommodate. This classical model assumes that each project is offered by one lecturer and that preference lists are strictly ordered. Here, we study a generalisation of spa-s where ties are allowed in the preference lists of students and lecturers, which we refer to as the Student-Project Allocation problem with lecturer preferences over Students with Ties (spa-st). We investigate stable matchings under the most robust definition of stability in this context, namely super-stability. We describe the first polynomial-time algorithm to find a super-stable matching or to report that no such matching exists, given an instance of spa-st. Our algorithm runs in O(L) time, where L is the total length of all the preference lists. Finally, we present results obtained from an empirical evaluation of the linear-time algorithm based on randomly-generated spa-st instances. Our main finding is that, whilst super-stable matchings can be elusive when ties are present in the students’ and lecturers’ preference lists, the probability of such a matching existing is significantly higher if ties are restricted to the lecturers’ preference lists.
Structural breaks in the interaction between bank and sovereign default risk
Authors: Lovreta Lidija , López Pascual Joaquín
Published: August 2020

The recent financial and sovereign debt crises emphasized the interdependence between bank and sovereign default risk and showed that major shocks may lead to a self-reinforcing negative spiral. In this paper, we analyse the pattern of interaction between bank and sovereign default risk by endogenously estimating the timing of structural breaks. The endogenous approach avoids the problem of choosing the number and the location of important turning points associated with the exogenous selection of break dates, commonly applied in the literature. In addition, it provides additional insight to which (if any) of the many exogenously proposed breaks are of particular importance to one specific economy, which can help policy makers to structure their actions accordingly. Using Spain during the 2008–2012 period as an illustrative example, we find supporting evidence for the three distinctive phases, marked by the breaks in the early-January and mid-May 2010. The three phases are characterized with an evident change in the bank–sovereign interaction, and we detect a bi-directional relationship only during the interim phase, i.e. at the very peak of the European sovereign debt crisis. We show that endogenously identified turning points coincide with important public events that affect investors’ perception about the government’s capacity and willingness to repay debt and support distressed banks. Finally, we provide evidence that structural dependence in the system extends to the interaction between bank and sovereign default risk volatility.
Diagnosis of COVID-19 using multiple antibody assays in two cases with negative PCR results from nasopharyngeal swabs
Authors: Traugott Marianna Theresia , Hoepler Wolfgang , Seitz Tamara , Baumgartner Sebastian , Karolyi Mario , Pawelka Erich , Friese Emanuela , Neuhold Stephanie , Kelani Hasan , Thalhammer Florian , Zoufaly Alexander , Laferl Hermann , Aberle Judith Helene , Wenisch Christoph , Puchhammer-Stöckl Elisabeth , Stiasny Karin , Aberle Stephan Walter , Weseslindtner Lukas
Published: August 2020

We report of two cases of progressed COVID-19 with negative PCR tests from nasopharyngeal swabs, in whom diagnosis was made by different antibody assays, including a lateral flow rapid test and multiple commercial ELISAs, finally confirmed by comprehensive serological assays. These cases highlight that commercial ELISAs and even rapid tests might significantly aid the diagnosis of COVID-19, particularly, if a combination of serological assays is used with a specific clinical question, in severely ill patients after seroconversion and when comprehensive serological methods are used for confirmation.
Beyond right or wrong: More effective feedback for formative multiple-choice tests
Authors: Ryan Anna , Judd Terry , Swanson David , Larsen Douglas P. , Elliott Simone , Katina Tzanetos Katina , Tzanetos Katina , Kulasegaram Kulamakan
Published: August 2020

Introduction The role of feedback in test-enhanced learning is an understudied area that has the potential to improve student learning. This study investigates the influence of different forms of post-test feedback on retention and transfer of biomedical knowledge within a test-enhanced learning framework. Methods 64 participants from a Canadian and an Australian medical school sat two single-best-answer formative multiple choice tests one week apart. We compared the effects of conceptually focused, response-oriented, and simple right/wrong feedback on a learner’s ability to correctly answer new (transfer) questions. On the first test occasion, participants received parent items with feedback, and then attempted items closely related (near transfer) to and more distant (far transfer) from parent items. In a repeat test at 1 week, participants were given different near and far transfer versions of parent items. Feedback type, and near and far transfer items were randomized within and across participants. Results Analysis demonstrated that response-oriented and conceptually focused feedback were superior to traditional right/wrong feedback for both types of transfer tasks and in both immediate and final retention test performance. However, there was no statistically significant difference between response-orientated and conceptually focused groups on near or far transfer problems, nor any differences in performance between our initial test occasion and the retention test 1 week later. As with most studies of transfer, participants’ far transfer scores were lower than for near transfer. Discussion Right/wrong feedback appears to have limited potential to augment test-enhanced learning.
National Preferred Interpersonal Distance Curbs the Spread of COVID-19: A Cross-Country Analysis
Authors: Gokmen Yunus , Turen Ufuk , Erdem Haluk , Tokmak İsmail
Published: August 2020

Objectives:

National interpersonal distance preference is considered a cultural characteristic. Interpersonal distance is critical for the spread dynamics of coronavirus disease 2019 (COVID-19). COVID-19’s spread trend shows various characteristics in different countries. We believe that 1 of the factors influencing this variation could be national interpersonal distance preference.

Methods:

We used regression analysis based on data of national interpersonal distance preferences (social, personal, and intimate) presented by Sorokowska et al. and COVID-19 rate of spread data for 40 different countries that were calculated using Our World in Data’s data.

Results:

National interpersonal distance preferences, with its 3 dimensions, significantly influence the rate of spread of COVID-19 in countries.

Conclusion:

Understanding the relation between national interpersonal distance preference and spread of COVID-19 might be very useful information in decision-making processes of individuals, societies, and governments to develop culturally well-suited counter-pandemic policies, strategies, and procedures during the COVID-19 pandemic or any epidemic or pandemic threats in the future, instead of standard fit-to-all strategies.
Healthcare worker perception of a global outbreak of novel coronavirus (COVID-19) and personal protective equipment: Survey of a pediatric tertiary-care hospital
Authors: Piché-Renaud Pierre-Philippe , Groves Helen E. , Kitano Taito , Arnold Callum , Thomas Angela , Streitenberger Laurie , Alexander Laura , Morris Shaun K. , Science Michelle
Published: August 2020

Objective:

In this study, we aimed to capture perspectives of healthcare workers (HCWs) on coronavirus disease 2019 (COVID-19) and infection prevention and control (IPAC) measures implemented during the early phase of the COVID-19 pandemic.

Design:

A cross-sectional survey of HCWs.

Participants:

HCWs from the Hospital for Sick Children, Toronto, Canada.

Intervention:

A self-administered survey was distributed to HCWs. We analyzed factors influencing HCW knowledge and self-reported use of personal protective equipment (PPE), concerns about contracting COVID-19 and acceptance of the recommended IPAC precautions for COVID-19.

Results:

In total, 175 HCWs completed the survey between March 6 and March 10: 35 staff physicians (20%), 24 residents or fellows (14%), 72 nurses (41%), 14 respiratory therapists (8%), 14 administration staff (8%), and 14 other employees (8%). Most of the respondents were from the emergency department (n = 58, 33%) and the intensive care unit (n = 58, 33%). Only 86 respondents (50%) identified the correct donning order; only 60 (35%) identified the correct doffing order; but the majority (n = 113, 70%) indicated the need to wash their hands immediately prior to removal of their mask and eye protection. Also, 91 (54%) respondents felt comfortable with recommendations for droplet and/or contact precautions for routine care of patients with COVID-19. HCW occupation and concerns about contracting COVID-19 outside work were associated with nonacceptance of the recommendations (P= .016 andP= .036 respectively).

Conclusion:

As part of their pandemic response plans, healthcare institutions should have ongoing training for HCWs that focus on appropriate PPE doffing and discussions around modes of transmission of COVID-19.
Inactivation of Severe Acute Respiratory Coronavirus Virus 2 (SARS-CoV-2) and Diverse RNA and DNA Viruses on Three-Dimensionally Printed Surgical Mask Materials
Authors: Welch Jennifer L. , Xiang Jinhua , Mackin Samantha R. , Perlman Stanley , Thorne Peter , O’Shaughnessy Patrick , Strzelecki Brian , Aubin Patrick , Ortiz-Hernandez Monica , Stapleton Jack T.
Published: August 2020

Background:

Personal protective equipment (PPE) is a critical need during the coronavirus disease 2019 (COVID-19) pandemic. Alternative sources of surgical masks, including 3-dimensionally (3D) printed approaches that may be reused, are urgently needed to prevent PPE shortages. Few data exist identifying decontamination strategies to inactivate viral pathogens and retain 3D-printing material integrity.

Objective:

To test viral disinfection methods on 3D-printing materials.

Methods:

The viricidal activity of common disinfectants (10% bleach, quaternary ammonium sanitizer, 3% hydrogen peroxide, or 70% isopropanol and exposure to heat (50°C, and 70°C) were tested on four 3D-printed materials used in the healthcare setting, including a surgical mask design developed by the Veterans’ Health Administration. Inactivation was assessed for several clinically relevant RNA and DNA pathogenic viruses, including severe acute respiratory coronavirus virus 2 (SARS-CoV-2) and human immunodeficiency virus 1 (HIV-1).

Results:

SARS-CoV-2 and all viruses tested were completely inactivated by a single application of bleach, ammonium quaternary compounds, or hydrogen peroxide. Similarly, exposure to dry heat (70°C) for 30 minutes completely inactivated all viruses tested. In contrast, 70% isopropanol reduced viral titers significantly less well following a single application. Inactivation did not interfere with material integrity of the 3D-printed materials.

Conclusions:

Several standard decontamination approaches effectively disinfected 3D-printed materials. These approaches were effective in the inactivation SARS-CoV-2, its surrogates, and other clinically relevant viral pathogens. The decontamination of 3D-printed surgical mask materials may be useful during crisis situations in which surgical mask supplies are limited.
Digitizing Premodern Text with the Chinese Text Project
Authors: Sturgeon Donald
Published: August 2020

The widespread availability of digitized premodern textual sources – together with increasingly sophisticated means for their manipulation – has brought enormous practical benefits to scholars whose work relies upon reference to their contents. While great progress has been made with the construction of ever more comprehensive database systems and archives, far more remains not only possible but also realistically achievable in the near future. This paper discusses some of the key challenges faced, and progress made towards solving them, in the context of a widely used open digital platform attempting to expand the range of digitized sources available while simultaneously increasing the scope of meaningful tasks that can be performed with them computationally. This paper aims to suggest how seemingly simple human-mediated additions to the digitized historical record – when combined with the power of digital systems to repeatedly perform mechanical tasks at enormous scales – quickly lead to transformative changes in the feasible scope of computational analysis of premodern writing.
Harvesting Big Biographical Data for Chinese History: The China Biographical Database (CBDB)
Authors: Tsui Lik Hang , Wang Hongsu
Published: August 2020

Biographies constitute the main historical record of China. The China Biographical Database (CBDB) is an important project that tackles this vast biographical material with digital technologies. With both online and offline versions, CBDB is meant to be useful for statistical, social network, and spatial analysis, as well as serving as biographical reference. Through the wide range of data it collects through mining historical texts and reference sources, CBDB offers multiple ways to examine the lives of past groups and individuals in Chinese history. The use of CBDB data for prosopographical and other types of analysis has generated important work that interprets Chinese history in new ways, and has also fostered new forms of digital humanities collaborations. This article introduces the history of the CBDB project and its methods for populating its biographical data. It also presents the ways that historians and other scholars could utilize its data for research and teaching.
The Visualization and Analysis of Historical Space
Authors: Bol Peter
Published: August 2020

A brief introduction to historical Geographic Information Systems and the creation of the China Historical GIS. Introductions are given to the CHGIS datasets covering 221 BCE to 1911 and the many GIS datasets on nineteenth and twentieth century China created under the leadership of the late G. William Skinner.
Creating, Linking, and Analyzing Chinese and Korean Datasets: Digital Text Annotation in MARKUS and COMPARATIVUS
Authors: De Weerdt Hilde
Published: August 2020

MARKUS, a multilingual digital text annotation and analysis platform, allows historians and other researchers to construct datasets from primary sources available to them in full-text digital format. Originally designed for those working with pre-twentieth-century Chinese texts, MARKUS has developed into a multifunctional annotation platform that is particularly suited for the automated annotation, referencing, and visualization of named entities in modern and literary Chinese and premodern Korean texts, but many of its additional annotation features can be used to analyze and read texts in any language, as long as the electronic documents are encoded in the most common standard for language encoding, Unicode. Below I discuss the main goals and methodological features of MARKUS and the allied text comparison utility COMPARATIVUS. I will illustrate these with some examples of how MARKUS has been used in Chinese and Korean historical research.
Primary Sourcing: the Ten Thousand Rooms Platform for Digital Annotation of Primary Source Images
Authors: Frisch Nicholas
Published: August 2020

The Ten Thousand Rooms Project offers a modern digital solution to an age-old scholarly problem: a platform for annotating source texts for easy reference and retrieval, while facilitating easy access to original sources. Individuals or groups can upload scans of primary sources and annotate over the image, in multiple layers, toggling annotations on or off per research and reading needs. The project is hosted by Yale University.
Local Gazetteers Research Tools: Overview and Research Application
Authors: Chen Shih-Pei , Hammond Kenneth J. , Gerritsen Anne , Wu Shellen , Zhang Jiajing
Published: August 2020

This article gives an overview of the Local Gazetteers Research Tools (LoGaRT), including its development, technical features, methodology, and examples of research applications by members of the Tu 圖 working group. The use of LoGaRT is illustrated with four brief introductions to projects that draw on visual materials from the local gazetteers, including ritual-related illustrations, city layout maps, and maps with western cartographic features. See the websites for more detailed information on LoGaRT and other research projects using it.1
The IntCal20 Approach to Radiocarbon Calibration Curve Construction: A New Methodology Using Bayesian Splines and Errors-in-Variables
Authors: Heaton Timothy J , Blaauw Maarten , Blackwell Paul G , Bronk Ramsey Christopher , Reimer Paula J , Scott E Marian
Published: August 2020

To create a reliable radiocarbon calibration curve, one needs not only high-quality data but also a robust statistical methodology. The unique aspects of much of the calibration data provide considerable modeling challenges and require a made-to-measure approach to curve construction that accurately represents and adapts to these individualities, bringing the data together into a single curve. For IntCal20, the statistical methodology has undergone a complete redesign, from the random walk used in IntCal04, IntCal09 and IntCal13, to an approach based upon Bayesian splines with errors-in-variables. The new spline approach is still fitted using Markov Chain Monte Carlo (MCMC) but offers considerable advantages over the previous random walk, including faster and more reliable curve construction together with greatly increased flexibility and detail in modeling choices. This paper describes the new methodology together with the tailored modifications required to integrate the various datasets. For an end-user, the key changes include the recognition and estimation of potential over-dispersion in14C determinations, and its consequences on calibration which we address through the provision of predictive intervals on the curve; improvements to the modeling of rapid14C excursions and reservoir ages/dead carbon fractions; and modifications made to, hopefully, ensure better mixing of the MCMC which consequently increase confidence in the estimated curve.
Importing the Human Factor into Safe Human–Robot Interaction Function Using the Bond Graph Method
Authors: Cheng Po-Jen , Ting Hsiang-Yuan , Huang Han-Pang
Published: August 2020

The variable stiffness actuator (VSA) is helpful to realize the post-collision safety strategies for safe human–robot interaction.1 The stiffness of the robot will be reduced to protect the user from injury when the collision between the robot and human occurs. However, The VSA has a mechanism limit constraint that can cause harm to users even if the stiffness is minimized. Accordingly, in this article, a concept combining danger index and robust fault detection and isolation is presented and applied to active–passive variable stiffness elastic actuator (APVSEA). APVSEA can actively change joint stiffness with the change of danger index. Experimental results show that this concept can effectively confirm the fault mode and provide additional protection measures to ensure the safety of users when the joint stiffness has been adjusted to the minimum.
Risk factors of severe cases with COVID-19: a meta-analysis
Authors: Ou Mingchun , Zhu Jieyun , Ji Pan , Li Hongyuan , Zhong Zhimei , Li Bocheng , Pang Jielong , Zhang Jianfeng , Zheng Xiaowen
Published: August 2020

Our study aimed to systematically analyse the risk factors of coronavirus disease 2019 (COVID-19) patients with severe disease. An electronic search in eight databases to identify studies describing severe or critically ill COVID-19 patients from 1 January 2020 to 3 April 2020. In the end, we meta-analysed 40 studies involving 5872 COVID-19 patients. The average age was higher in severe COVID-19 patients (weighted mean difference; WMD = 10.69, 95%CI 7.83–13.54). Patients with severe disease showed significantly lower platelet count (WMD = −18.63, 95%CI −30.86 to −6.40) and lymphocyte count (WMD = −0.35, 95%CI −0.41 to −0.30) but higher C-reactive protein (CRP; WMD = 42.7, 95%CI 31.12–54.28), lactate dehydrogenase (LDH; WMD = 137.4, 95%CI 105.5–169.3), white blood cell count（WBC), procalcitonin（PCT）, D-dimer, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and creatinine（Cr）. Similarly, patients who died showed significantly higher WBC, D-dimer, ALT, AST and Cr but similar platelet count and LDH as patients who survived. These results indicate that older age, low platelet count, lymphopenia, elevated levels of LDH, ALT, AST, PCT, Cr and D-dimer are associated with severity of COVID-19 and thus could be used as early identification or even prediction of disease progression.
Reasons Internalism and the Problem of Depression
Authors: Spaid Andrew
Published: August 2020

This article looks at a version of the “too-few-reasons” problem for reasons internalism stemming from the existence of cases of clinical depression. People with clinical depression lack motivation to do things like go to work or seek treatment for their depression. Internalism appears committed to saying that such people lack reasons to do these things since internalism makes having reasons depend on having motivations. But, intuitively, depressed people do have reasons to do them. This article considers a number of possible solutions to this problem, such as that depressed people have actual or ideal desires which explain their reasons, and argues that these solutions do not succeed.