bluuebunny/crossref_metadata_2025 huggingface dataset:
Agnosticism as settled indecision
Authors: Wagner Verena
Published: June 2021

In this paper, I spell out a descriptive account of agnosticism that captures the intuitive view that a subject enters the mental state of agnosticism via an act or event called suspension. I will argue that agnosticism is a complex mental state, and that the formation of an attitude is the relevant act or event by which a subject commits to indecision regarding some matter. I will suggest a ‘two-component analysis’ that addresses two aspects that jointly account for the settled state of agnosticism: (1) the subject’s de facto indecision and (2) the subject’s commitment to her indecision. Unlike meta-cognitivist or sui generis accounts, I do not take the agnostic’s commitment to indecision as constitutive for her indecision but rather as an evaluation or qualification of the indecision that she already exhibits. Agnosticism, thus, is a settled form of indecision that marks the end of inquiry.
Forest management to increase carbon sequestration in boreal Pinus sylvestris forests
Authors: Jörgensen Karolina , Granath Gustaf , Lindahl Björn D. , Strengbom Joachim
Published: June 2021

Background and aims

Forest management towards increased carbon (C) sequestration has repeatedly been suggested as a “natural climate solution”. We evaluated the potential of altered management to increase C sequestration in borealPinus sylvestrisforest plantations.

Methods

At 29 forest sites, distributed along a 1300 km latitudinal gradient in Sweden, we studied interactive effects of fertilization and thinning on accumulation of C in standing biomass and the organic horizon over a 40 year period.

Results

Abstention from thinning increased the total C stock by 50% on average. The increase was significant (14% on average) even when C in the removed timber was included in the total ecosystem C pool. Fertilization of thinned stands increased stocks similarly regardless of including (11%) or excluding (12%) removed biomass, and fertilization combined with abstention from thinning had a synergistic effect on C stocks that generated an increase of 79% (35% when removed timber was included in the C stock). A positive effect of fertilization on C stocks was observed along the entire gradient but was greater in relative terms at high latitudes. Fertilization also reduced soil respiration rates.

Conclusion

Taken together, our results suggest that changed forest management practices have major potential to increase the C sink of boreal forests. Although promising, these benefits should be evaluated against the undesired effects that such management can have on economic revenue, timber quality, biodiversity and delivery of other ecosystem services.
Estimating corporate bankruptcy forecasting models by maximizing discriminatory power
Authors: Charalambous Chris , Martzoukos Spiros H. , Taoushianis Zenon
Published: June 2021

In this paper, we estimate coefficients of bankruptcy forecasting models, such as logistic and neural network models, by maximizing their discriminatory power as measured by the Area Under Receiver Operating Characteristics (AUROC) curve. A method is introduced and compared with traditional logistic and neural network models, using out-of-sample analysis, in terms of discriminatory power, information content and economic impact while we forecast bankruptcy one year ahead, two years ahead but also financial distress, which is a situation that precedes firm bankruptcy. Using US public firms over the period 1990–2015, in all, we find that training models to maximize AUROC, provides more accurate out-of-sample forecasts relative to training them with traditional methods, such as maximizing the log-likelihood function, highlighting the benefits arising by using models with maximized AUROC. Among all models, however, a neural network trained with our method is the best performing one, even when we compare it with other methods proposed in the literature to maximize AUROC. Finally, our results are more pronounced when we increase the forecasting difficulty, such as forecasting financial distress. The implementation of our method to train bankruptcy models is robust in various settings and therefore well-justified.
Mind the gender gap: the impact of university education on the entrepreneurial entry of female and male STEM graduates
Authors: Piva Evila , Rovelli Paola
Published: June 2021

Women are consistently underrepresented among graduate entrepreneurs. This is especially true among the entrepreneurs who graduate in STEM fields. Here, we aim at identifying factors that reduce/enlarge the gender imbalance in entrepreneurship among STEM graduates. In particular, we explore the underinvestigated association between university education in STEM fields and entrepreneurial entry of recent female and male graduates considering graduates’ whole university curriculum. Our analyses on the graduates who obtained a Master of Science degree in the 2005–2009 period from Politecnico di Milano reveal that training in economics and management reduces the gender imbalance in entrepreneurial entry among STEM recent graduates. The gap is instead larger among the graduates who attended courses that aggregate students from different STEM fields or did an internship.
Non-invasive, real time in-situ techniques to determine the ripening stage of banana
Authors: Ringer Tilman , Blanke Michael
Published: June 2021

Bananas were examined starting from ripening stage R2 (green) to stage R7 (overripe), to identify suitable non-invasive, real time in-situ technologies to separate the ripening stages: (1) Chlorophyll degradation, measured by the DA meter, decreased from ca. 2.1 (R2) to 0.2 IAD units (R7), i.e. tenfold decline. (2) Colour CIE-Lab a values dramatically increased as indication of chlorophyll breakdown and enable differentiation between all ripening stages R2 to R7. Colour angles declined from 98.7° hue (R2), 97.3° hue (R3), 92.7° hue (R4), 89.4° hue (R5); 87.5° hue (R6) until 82.0° hue (R7). (3) Spectroscopy showed two light reflectance troughs at 494 nm and 679 nm. A novel banana ripening index (BRI) was developed and is proposed to identify and distinguish the ripening stages of banana with values starting at 4 at R1 and peaking at 8.1 at ripening stage R7. (4) Peel gloss increased from stage R2 (150 a.u.) to stage R7 (220 a.u.) in the order of ca. 50% followed by a subsequent decrease thereafter. (5) Peel softening declined as fruit firmness dropped from 82 Shore at stage R2 to 42 Shore at stage R7 (overripe), measured also at the centre of the banana fruit. (6) After a constant 90.5% water content per fresh mass (FM) in the banana peel until stage R5, the subsequent drop to 82.9% FM at R7 and 7.6% water translocation viz displacement from the peel to pulp explained this softening. All the above results identified the fruit centre (rather than the tip) as a suitable candidate due to the most advanced ripening and least curved surface region of the fruit with easy access, when a carton is opened and the hands become accessible. This novel approach based on a comparison has shown the DA-meter, colorimeter and spectrometer as suitable candidates for the identification of each ripening stage. The combination of these three devices may be suitable for monitoring of banana ripening rooms in terms of temperature and humidity in addition to the present, colour-based ripening scale.
e-Pharmacophore model-guided design of potential DprE1 inhibitors: synthesis, in vitro antitubercular assay and molecular modelling studies
Authors: Kumar Avinash , Rajappan Revathi , Kini Suvarna G. , Rathi Ekta , Dharmarajan Sriram , Sreedhara Ranganath Pai K.
Published: June 2021

Tuberculosis continues to wreak havoc worldwide and caused around 1.4 million deaths in 2019. Hence, in our pursuit of developing novel antitubercular compounds, we are reporting the e-Pharmacophore-based design of DprE1 (decaprenylphosphoryl-ribose 2′-oxidase) inhibitors. In the present work, we have developed a four-feature e-Pharmacophore model based on the receptor–ligand cavity of DprE1 protein (PDB ID 4P8C) and mapped our previous reported library of compounds against it. The compounds were ranked on phase screen score, and the insights obtained from their alignment were used to design some novel compounds. The designed compounds were docked with DprE1 protein in extra-precision mode using Glide module of Maestro, Schrodinger. Some derivatives like B1, B2, B4, B5 and B12 showed comparable docking score (docking score > − 6.0) with respect to the co-crystallized ligand. The designed compounds were synthesized and characterized. In vitro antitubercular activity was carried out on Mycobacterium tuberculosis H37Rv (ATCC27294) strain using the agar dilution method, and minimum inhibitory concentration (MIC) was determined. The compound B12 showed a MIC value of 1.56 μg/ml which was better than the standard drug ethambutol (3.125 μg/ml). Compounds B7 and B11 were found to be equipotent with ethambutol. Cytotoxicity studies against Vero cell lines proved that these compounds were non-cytotoxic. Molecular dynamic simulation study also suggests that compound B12 will form a stable complex with DprE1 protein and will show the crucial H-bond interaction with LYS418 residue. Further in vitro enzyme inhibition studies are required to validate these findings.
The Genetic Basis of Hypertriglyceridemia
Authors: Carrasquilla Germán D. , Christiansen Malene Revsbech , Kilpeläinen Tuomas O.
Published: June 2021

Purpose of Review

Hypertriglyceridemia is a common dyslipidemia associated with an increased risk of cardiovascular disease and pancreatitis. Severe hypertriglyceridemia may sometimes be a monogenic condition. However, in the vast majority of patients, hypertriglyceridemia is due to the cumulative effect of multiple genetic risk variants along with lifestyle factors, medications, and disease conditions that elevate triglyceride levels. In this review, we will summarize recent progress in the understanding of the genetic basis of hypertriglyceridemia.

Recent Findings

More than 300 genetic loci have been identified for association with triglyceride levels in large genome-wide association studies. Studies combining the loci into polygenic scores have demonstrated that some hypertriglyceridemia phenotypes previously attributed to monogenic inheritance have a polygenic basis. The new genetic discoveries have opened avenues for the development of more effective triglyceride-lowering treatments and raised interest towards genetic screening and tailored treatments against hypertriglyceridemia.

The discovery of multiple genetic loci associated with elevated triglyceride levels has led to improved understanding of the genetic basis of hypertriglyceridemia and opened new translational opportunities.
Simultaneous 3D Visualization of the Microvascular and Neural Network in Mouse Spinal Cord Using Synchrotron Radiation Micro-Computed Tomography
Authors: Jiang Liyuan , Li Chengjun , Li Miao , Yin Xianzhen , Wu Tianding , Duan Chunyue , Cao Yong , Lu Hongbin , Hu Jianzhong
Published: June 2021

Effective methods for visualizing neurovascular morphology are essential for understanding the normal spinal cord and the morphological alterations associated with diseases. However, ideal techniques for simultaneously imaging neurovascular structure in a broad region of a specimen are still lacking. In this study, we combined Golgi staining with angiography and synchrotron radiation micro-computed tomography (SRμCT) to visualize the 3D neurovascular network in the mouse spinal cord. Using our method, the 3D neurons, nerve fibers, and vasculature in a broad region could be visualized in the same image at cellular resolution without destructive sectioning. Besides, we found that the 3D morphology of neurons, nerve fiber tracts, and vasculature visualized by SRμCT were highly consistent with that visualized using the histological method. Moreover, the 3D neurovascular structure could be quantitatively evaluated by the combined methodology. The method shown here will be useful in fundamental neuroscience studies.
Debating Sex and Sovereignty: Uganda’s New National Sexuality Education Policy
Authors: Moore Erin V. , Hirsch Jennifer S. , Spindler Esther , Nalugoda Fred , Santelli John S.
Published: June 2021

Introduction

This article examines recent moral panics over sex education in Uganda from historical perspectives. Public outcry over comprehensive sexuality education erupted in 2016 over claims that children were being taught “homosexuality” by international NGOs. Subsequent debates over sex education revolved around defending what public figures claimed were national, religious, and cultural values from foreign infiltration.

Methods

This paper is grounded in a survey of Uganda’s two English-print national newspapers (2016–2018), archival research of newspapers held at Uganda’sVision Groupmedia company (1985–2005), analyses of public rhetoric as reported in internationally and nationally circulating media, textual analysis of Uganda’s National Sexuality Education Framework (2018), formal interviews with Ugandan NGO officers (3), and semi-structured interviews with Ugandan educators (3).

Results

Uganda’s current panic over sex education reignited longstanding anxieties over foreign interventions into the sexual health and rights of Ugandans. We argue that in the wake of a 35-year battle with HIV/AIDS and more recent controversies over LGBT rights, both of which brought international donor resources and governance, the issue of where and how to teach young people about sex became a new battleground over the state’s authority to govern the health and economic prosperity of its citizens.

Conclusions

Ethno- and religio-nationalist rhetoric used to oppose the state’s new sexuality education policy was also used to justify sex education as a tool for economic development.

Policy Implications

Analyzing rhetoric mobilized by both supporters and detractors of sex education reveals the contested political terrain policy advocates must navigate in Uganda and other postcolonial contexts.
Evaluation of the aircraft fuel economy using advanced statistics and machine learning
Authors: Baumann S. , Neidhardt T. , Klingauf U.
Published: June 2021

Fuel represents a significant proportion of an airline’s operating costs. Statistical analyses and physical models have been used to monitor and estimate fuel consumption up to now, but these can have considerable inaccuracies. This means that, currently, there are no suitable detection methods for the evaluation of aircraft retrofits, of which some only suggest a fuel efficiency potential in the tenths of a percent range. This article examines suitable assessments of the fuel economy of aircraft and especially aircraft with and without retrofitting. For this purpose, the effects of technical influences such as measurement errors and external uncertainties such as turbulence on the evaluation of the fuel economy are examined in more detail. The focus of the article is on a discussion of possible optimization potentials of conventional statistical evaluation methods, especially regarding possible misinterpretations and spurious correlations. This discussion is exemplarily based on a case study of simulated flight data of an Airbus A320 (with and without improved wing tips (sharklets) as an exemplary retrofit). For this purpose, a suitable simulation environment is presented in which relevant environmental parameters such as wind and turbulence can be set, and measurement errors in the recorded data can be manipulated. It is found that measurement errors as well as turbulence can lead to a bias in key figures that are used for the evaluation of fuel flow signals. The effect of turbulence can partly be mitigated by the use of an improved key figure the authors propose. The investigation is also carried out using a data-based evaluation method to simulate the fuel flow using a machine learning model (random forests), whereby the effects of turbulence and measurement errors significantly influence the fuel flow predicted by the model in the same order of magnitude as potential retrofit measures.
Protected area management in a post-natural world: negotiated governance at the Danish Wadden Sea
Authors: Walsh Cormac
Published: June 2021

National parks and other large protected areas play an increasingly important role in the context of global social and environmental challenges. Nevertheless, they continue to be rooted in local places and cannot be separated out from their socio-cultural and historical context. Protected areas furthermore are increasingly understood to constitute critical sites of struggle whereby the very meanings of nature, landscape, and nature-society relations are up for debate. This paper examines governance arrangements and discursive practices pertaining to the management of the Danish Wadden Sea National Park and reflects on the relationship between pluralist institutional structures and pluralist, relational understandings of nature and landscape.
Contribution of Research in the West Indies and Northeast Amazonia to Knowledge of the 2014–2015 Chikungunya Epidemic in the Americas
Authors: Bonifay Timothee , Godaert Lidvine , Epelboin Yanouk , Rousset Dominique , Douine Maylis , Hilderal Hélène , Clavel Cyril , Abel Sylvie , Najioullah Fatiha , Fagour Laurence , do Socorro Mendonça Gomes Margarete , Lacerda Marcus , Cézaire Raymond , Elenga Narcisse , Dramé Moustapha , Hoen Bruno , Cabié André , Djossou Félix , Epelboin Loïc
Published: June 2021

Purpose of Review

Although the chikungunya virus was discovered more than 60 years ago, it has only really been studied since the outbreak in La Reunion in 2005–2006. Ten years later, between 2014 and 2015, the chikungunya virus spread throughout the Americas, affecting millions of people. The objective of this review is to describe the contributions of research on chikungunya virus infection gained from epidemic in the West Indies and the Guiana Shield.

Recent Findings

Prevalence data were similar to those found in the Indian Ocean or Asia during epidemics. Clinically, there is now a better understanding of the typical, atypical, and severe forms. Several studies have insisted on the presence of neurological forms of chikungunya infection, such as encephalitis or Guillain–Barré syndrome. Cases of septic shock due to chikungunya virus as well as thrombotic thrombocytopenic purpura were described for the first time. Given the magnitude of the epidemic and the large number of people affected, this has led to a better description and new classifications of chikungunya virus infections in specific populations such as pregnant women, the elderly, and children. Several studies also described the behavior of populations faced with an emerging disease.

Current epidemiological data from tropical regions highlights the risk of spreading emerging diseases at higher latitudes, especially concerning arboviruses, since the vector Aedes albopictus is already established in many parts of northern countries. A better understanding of the disease and its epidemic dynamics will foster better management, the crucial importance of which was demonstrated during the COVID-19 epidemic.
Selection of third party reverses logistic providers: an approach of BCF-CRITIC-MULTIMOORA using Archimedean power aggregation operators
Authors: Baidya Jhulaneswar , Garg Harish , Saha Abhijit , Mishra Arunodaya Raj , Rani Pratibha , Dutta Debjit
Published: June 2021

One of the most powerful tools to operate imprecision is bipolar complex fuzzy sets (BCFSs), which is an enlargement of bipolar fuzzy sets (BFSs) as well as complex fuzzy sets (CFSs). This paper deals with an integrated MULTIMOORA (multi-objective optimization on the basis of ratio analysis plus full multiplicative form) framework as a generalization of fuzzy MULTIMOORA procedure to assess the multi-criteria decision-making (MCDM) problems with BCFSs. We develop BCF-Archimedean power weighted (ordered weighted) arithmetic and geometric aggregation operators (AOs) and discuss their properties from this point of view. The proposed Archimedean power-weighted AOs can eliminate the influence of extreme evaluating criteria values from some biased experts with different preference attitudes under the BCF setting. Afterward, we put forward an integrated MULTIMOORA algorithm based on the proposed AOs, where criteria weights are estimated using the CRITIC (criteria importance through inter-criteria correlation) method, which is a well-known objective weighting method based on aggregated score values of options, intensity contrast of every criteria and conflict among attributes. In the proposed methodology, criteria values are aggregated based on the MULTIMOORA method that involves three sub-methods: the ‘ratio system’, the ‘reference point’ and the ‘full multiplicative form’ and thus takes less computational time, minimum mathematical evaluations and bears good stability. In the following, third-party reverse logistics providers' (3PRLP) selection problem is brought into consideration to manifest the sufficiency of the developed methodology. At the end of this study, we draw attention to a comparison between the proposed decision-making approach with the corresponding BCF-CRITIC-TOPSIS and BCF-CRITIC-WASPAS methods.
DP-TABU: an algorithm to solve single-depot multi-line vehicle scheduling problem
Authors: Xinchao Zhao , Hao Sun , Juan Lu , Zhiyu Li
Published: June 2021

A DP-TABU algorithm is proposed which can effectively solve the multi-line scheduling problem of single Deport (SD-ML-VSP). The multi-line regional coordinated dispatch of the single-line deport of the bus is to solve the problems of idle low-peak vehicles and insufficient peak capacity in single-line scheduling. The capacity of multiple lines at the same station is adjusted to realize resource sharing such as timetables, vehicles, and drivers. Shared capacity such as bus departure intervals and bus schedules. Taking the regional scheduling of multiple lines at the same station as the service object, a vehicle operation planning model based on the objective of optimal public transportation resources (minimum bus and driver costs) is established to optimize the vehicle dispatching mode of multiple lines. We applied this algorithm to the three lines S105, S107, and S159 of Zhengzhou Public Transport Corporation, and the results proved that the algorithm is effective. Through comparison with manual scheduling and simulated annealing algorithm, the advantages of DP-TABU algorithm in performance optimization and robustness are further verified.
Aggregation-Induced Emission in Electrochemiluminescence: Advances and Perspectives
Authors: Moreno-Alcántar Guillermo , Aliprandi Alessandro , De Cola Luisa
Published: June 2021

The discovery of aggregation-induced electrochemiluminescence (AIECL) in 2017 opened new research paths in the quest for novel, more efficient emitters and platforms for biological and environmental sensing applications. The great abundance of fluorophores presenting aggregation-induced emission in aqueous media renders AIECL a potentially powerful tool for future diagnostics. In the short time following this discovery, many scientists have found the phenomenon interesting, with research findings contributing to advances in the comprehension of the processes involved and in attempts to design new sensing platforms. Herein, we explore these advances and reflect on the future directions to take for the development of sensing devices based on AIECL.

Graphic abstract
Nonlinear emergent macroscale PDEs, with error bound, for nonlinear microscale systems
Authors: Bunder J. E. , Roberts A. J.
Published: June 2021

Many multiscale physical scenarios have a spatial domain which is large in some dimensions but relatively thin in other dimensions. These scenarios includes homogenization problems where microscale heterogeneity is effectively a ‘thin dimension’. In such scenarios, slowly varying, pattern forming, emergent structures typically dominate the large dimensions. Common modelling approximations of the emergent dynamics usually rely on self-consistency arguments or on a nonphysical mathematical limit of an infinite aspect ratio of the large and thin dimensions. Instead, here we extend to nonlinear dynamics a new modelling approach which analyses the dynamics at each cross-section of the domain via a multivariate Taylor series (Roberts and Bunder in IMA J Appl Math 82(5):971–1012, 2017. 10.1093/imamat/hxx021). Centre manifold theory extends the analysis at individual cross-sections to a rigorous global model of the system’s emergent dynamics in the large but finite domain. A new remainder term quantifies the error of the nonlinear modelling and is expressed in terms of the interaction between cross-sections and the fast and slow dynamics. We illustrate the rigorous approach by deriving the large-scale nonlinear dynamics of a thin liquid film on a rotating substrate. The approach developed here empowers new mathematical and physical insight and new computational simulations of previously intractable nonlinear multiscale problems.
Effects of contamination with gasoline on engineering properties of fine-grained silty soils with an emphasis on the duration of exposure
Authors: Yazdi Abdollah , Sharifi Teshnizi Ebrahim
Published: June 2021

Leaking tanks may lead to severe contamination of their surrounding soil. The geotechnical behavior of the soil varies with the physicochemical processes that occur between the contaminant and the soil. In this respect, studying the geochemical properties of gasoline-contaminated soils and sediments seems to be important for engineering and especially environmental purposes. In this paper, laboratory tests were carried out to examine the effects of crude gasoline contamination on some of the geotechnical properties of a silty soil sampled from the Mashhad plain, located in the northeast of Iran. Tests consisted of basic properties, Atterberg limits, compaction, direct shear, and uniaxial compression tests, which were carried out on clean and contaminated soil samples at the same densities. The contaminated samples were prepared by mixing the soils with crude gasoline in the amounts of 3%, 6%, 9%, and 12% of dry weight and curing periods of 0, 7, 15, and 30 days. Results indicated a decrease in the friction angle and an increase in the cohesion of the soil by increasing gasoline content. Besides, a reduction in the maximum dry density and optimum moisture content was observed in the compaction test. The increase in gasoline percentage up to 6% also showed a direct effect on increasing the liquid limit and plastic limit of silty soil, which decreased thereafter. Moreover, any increase in gasoline percentage had a reverse effect on the modulus of elasticity of the soil. The increase in gasoline percentage up to 3% also had a direct impact on the uniaxial compressive strength of the soil, exceeding which it started to decline. Finally, the effects of contamination duration were examined by testing contaminated samples in periods of 7, 15, and 30 days under natural conditions. The results showed a reverse relationship with all geotechnical properties due to aging and a reduction in the gasoline content due to the evaporation of volatile compounds. Also, the numerical analysis of the laboratory results indicated an increase in settling and the percentage of shear strain beneath the foundation with increasing the contamination level, confirming the laboratory results.
Investigating forest fragmentation through earth observation datasets and metric analysis in the tropical rainforest area
Authors: Pyngrope Osaka Ruandache , Kumar Mukesh , Pebam Rocky , Singh Sudhir Kumar , Kundu Arnab , Lal Deepak
Published: June 2021

Extensive mining operations, deforestation, jhumming, and soil erosion coupled with population stress in the study area have put an adverse effect on its forest resources. This study investigates the transition in forest cover classes and its fragmentation in the Jaiñtia Hills District of Meghalaya (India). Satellite data (multispectral images from Landsat 5 and 8) for 1995, 2001, 2007, and 2015 were classified using the supervised classification method. Landscape metrics from the classified images were calculated using FRAGSTATS. The overall accuracy of classification was found to be 87.50% (1995), 87.50% (2001), 85.00% (2007) and 91.67% (2015), respectively. The results revealed an increase in dense forest with an increase in the patch number from 1995 to 2007. Additionally, a decrease in non-forest cover with an increase in the number of patches from 2001 to 2015 was observed which further suggests fragmentation. It has been reported that 8.13% of the dense forest increased and 19.47% of non-forested areas decreased during the study period. Overall, this study highlights the changes in the distribution of forest area which could aid policy makers to adopt appropriate forest conservation strategies.
Modeling and optimization of cutting forces and effect of turning parameters on SiCp/Al 45% vs SiCp/Al 50% metal matrix composites: a comparative study
Authors: Laghari Rashid Ali , Li Jianguang
Published: June 2021

In this study, the proposed experimental and second-order model for the cutting forces were developed through several parameters, including cutting speed, feed rate, depth of cut, and two varying content of SiCp. Cutting force model was developed and optimized through RSM and compared for two different percentages of components SiCp/Al 45% and SiCp/Al 50%. ANOVA is used for Quantitative evaluation, the main effects plot along with the evaluation using different graphs and plots including residual analysis, contour plots, and desirability functions for cutting forces optimization. It provides the finding for choosing proper parameters for the machining process. The plots show that during increment with depth of cut in proportion with feed rate are able to cause increments in cutting forces. Higher cutting speed shows a positive response in both the weight percentage of SiCp by reducing the cutting force because of higher cutting speed increases. A very fractional increasing trend of cutting force was observed with increasing SiCp weight percentages. Both of the methods such as experiment and model-predicted results of SiCp/Al MMC materials were thoroughly evaluated for analyzing cutting forces of SiCp/Al 45%, and SiCp/Al 50%, as well as calculated the error percentages also found in an acceptable range with minimal error percentages.

Article Highlights

This study focuses on the effect of cutting parameters as well as different percentage of SiC particles on the cutting forces, while comparing the results of both SiC particles such as SiCp/Al 45%, and SiCp/Al 50% the result shows that there isn’t fractional amount of impact on the cutting force with nominal increasing percentages of SiC particles.

Cutting speed in machining process of SiCp/Al shows positive response in reducing the cutting forces, however, increasing amount of depth of cut followed by increasing feed rate creates fluctuations in cutting force and thus increases the cutting force in the cutting process.

The developed RSM mathematical model which is based on the box Behnken design show excellent competence for predicting and suggesting the machining parameters for both SiCp/Al 45%, and SiCp/Al 50% and the RSM mathematical model is feasible for optimization of the machining process with good agreement to experimental values.
Examining Elementary Social Studies Preservice Teachers’ Dispositional Thinking about Museum Pedagogy
Authors: Hubbard Janie , Odebiyi Oluseyi Matthew
Published: June 2021

Evidence is limited on how elementary social studies preservice teachers make sense of museum settings and the use of museum artifacts for instruction, especially while consumed with learning how to teach. This study explored 81 elementary preservice teachers’ dispositional thinking toward museum pedagogy in a teacher education program. Objectives were to determine an overall dispositional thinking profile and also investigate possible distinct dimensions. The study employed descriptive and exploratory factor analysis (EFA) to establish systematically reliable factor solutions representing a profile of preservice teachers’ dispositions. Results indicate preservice teachers’ museum pedagogy dispositional thinking can be measured with three dimensions and one overall generic form of dispositional thinking. Representing the dimensions are these factor structures: (a) willingness to use museum settings and their artifacts to support social studies teaching, (b) capacity to interact with museum artifacts for K-6 social studies teaching, and (c) recognizing the prospect of museum pedagogy as an approach to enhance K-6 social studies education. Based on the factor structures, we introduce a conceptual framework to represent elementary social studies preservice teachers’ dispositional thinking about museum pedagogy. Engaging in preliminary work to first understand preservice teachers’ thoughts and dispositions, before creating or adopting curricula, may deepen and strengthen their agentic growth in museum education for social studies teaching.
Curriculum Development in Language Teaching
Authors: Richards Jack C.
Published: June 2021

Curriculum Development in Language Teaching 2nd edition has been thoroughly revised and updated to reflect contemporary issues in curriculum. As well as describing and examining a traditional product-focused curriculum perspective, it considers curriculum from the perspective of classroom processes. Case studies, which are used to exemplify issues and questions - within and at the end of each chapter - allow for reflection and discussion.
Comparing Tropopause‐Penetrating Convection Identifications Derived From NEXRAD and GOES Over the Contiguous United States
Authors: Cooney John W. , Bedka Kristopher M. , Bowman Kenneth P. , Khlopenkov Konstantin V. , Itterly Kyle
Published: June 2021

Overshooting tops (OTs) are a well‐known indicator of updrafts capable of transporting air from the troposphere to the stratosphere and generating hazardous weather conditions. Satellites and radars have long been used to identify OTs, but the results have not been entirely consistent due to differences in sensor and measurement characteristics. OT detection approaches based on satellite infrared (IR) imagery have often been validated using human‐expert OT identifications, but such datasets are time‐consuming to compile over broad geographic regions. Despite radar limitations to detect the true physical cloud top, OTs identified within multi‐radar composites can serve as a stable reference for comprehensive satellite OT analysis and detection validation. This study analyzes a large OT data set compiled from Geostationary Operational Environmental Satellites (GOES)‐13/16 geostationary IR data and gridded volumetric Next‐Generation Radar (NEXRAD) reflectivity to better understand radar and IR observations of OTs, quantify agreement between satellite and radar OT detections, and demonstrate how an increased spatial sampling from GOES‐13 to GOES‐16 impacts OT appearance and detection performance. For nearly time‐matched scenes and moderate OT probability, the GOES‐13 detection rate (∼60%) is ∼15% lower than GOES‐16 (∼75%), which is mostly attributed to coarser spatial resolution. NEXRAD column‐maximum reflectivity and tropopause‐relative echo‐top height as a function of GOES OT probability were quite consistent between the two satellites however, indicating that efforts to account for differing resolution were largely successful. GOES false detections are unavoidable because outflow from nearby or recently decayed OTs can be substantially colder than the tropopause and look like an OT to an automated algorithm.
Recent Advances in Detection of Overshooting Cloud Tops From Longwave Infrared Satellite Imagery
Authors: Khlopenkov Konstantin V. , Bedka Kristopher M. , Cooney John W. , Itterly Kyle
Published: June 2021

This paper describes an updated method for automated detection of overshooting cloud tops (OT) using a combination of spatial infrared (IR) brightness temperature patterns and modeled tropopause temperature. IR temperatures are normalized to the tropopause, which serves as a stable reference that modulates how cold a convective cloud should become within a given region. Anvil clouds are identified using histogram analysis and cold spots embedded within anvils serve as OT candidate regions. OT candidates are then assigned an OT probability, which can be interpreted as a metric of storm intensity and an estimate of confidence in a detection for a particular pixel. It is produced using an original mathematical composition of four factors: Tropopause‐normalized temperature, prominence relative to the surrounding anvil, surrounding anvil area, and spatial uniformity of anvil temperature, which are calculated from empirically derived sensitivity curves. The shape of the curves is supported by independent analysis of a large sample of matched IR and radar‐derived OT regions. An optimal sensitivity for each factor was determined by maximizing correlation between the OT probability and a set of human‐identified OT regions. Coarser spatial resolution of GOES‐13 data cause OTs to be less prominent compared to GOES‐16, necessitating different sensitivities for each satellite. Detection performance is quantified for each satellite based on human OT identifications and as a function of how prominent the OT appeared in visible and IR imagery. Based on analyses of human‐identified OTs, OT detection accuracy, defined by the area under a receiver operating characteristic curve, is determined to be 0.94 for GOES‐16 and 0.78 for GOES‐13.
Implementation and Impacts of Surface and Blowing Snow Sources of Arctic Bromine Activation Within WRF‐Chem 4.1.1
Authors: Marelle Louis , Thomas Jennie L. , Ahmed Shaddy , Tuite Katie , Stutz Jochen , Dommergue Aurélien , Simpson William R. , Frey Markus M. , Baladima Foteini
Published: June 2021

Elevated concentrations of atmospheric bromine are known to cause ozone depletion in the Arctic, which is most frequently observed during springtime. We implement a detailed description of bromine and chlorine chemistry within the WRF‐Chem 4.1.1 model, and two different descriptions of Arctic bromine activation: (1) heterogeneous chemistry on surface snow on sea ice, triggered by ozone deposition to snow (Toyota et al., 2011 https://doi.org/10.5194/acp-11-3949-2011), and (2) heterogeneous reactions on sea salt aerosols emitted through the sublimation of lofted blowing snow (Yang et al., 2008, https://doi.org/10.1029/2008gl034536). In both mechanisms, bromine activation is sustained by heterogeneous reactions on aerosols and surface snow. Simulations for spring 2012 covering the entire Arctic reproduce frequent and widespread ozone depletion events, and comparisons with observations of ozone show that these developments significantly improve model predictions during the Arctic spring. Simulations show that ozone depletion events can be initiated by both surface snow on sea ice, or by aerosols that originate from blowing snow. On a regional scale, in spring 2012, snow on sea ice dominates halogen activation and ozone depletion at the surface. During this period, blowing snow is a major source of Arctic sea salt aerosols but only triggers a few depletion events.
Volatile Element Evidence of Local MORB Mantle Heterogeneity Beneath the Southwest Indian Ridge, 48°–51°E
Authors: Wang Wei , Kelley Katherine A. , Li Zhenggang , Chu Fengyou , Dong Yunpeng , Chen Ling , Dong Yanhui , Li Jie
Published: June 2021

The mantle source beneath the Southwest Indian Ridge (SWIR) reflects a complex history of contamination. Magmatic volatile contents are vital tracers of these kinds of heterogeneities, which may fractionate otherwise constant volatile/non‐volatile elemental ratios, such as the H2O/Ce ratio. Although several studies have recently used trace element and isotopic data to address mantle source heterogeneity and magmatic processes at SWIR 48°–51°E region, volatile element constraints provide a valuable test of models for the origins of mantle heterogeneities in this region. Here, we present new data for nine rare basaltic glass samples from the 48°–51°E region, which enable careful assessment of the effects of primary versus secondary processes on the glass volatile contents. These samples are strongly affected by variable extents of carbon degassing, and shallow assimilation of Cl‐rich fluid, but also reveal consistently high H2O/Ce ratios (458.8 ± 14.9), among the highest in MORBs, that cannot be explained by late‐stage secondary processes, crustal assimilation, or simple melting of peridotite mantle at variable depths. Instead, the high H2O/Ce ratios are features of the mantle source composition. The 48°–51°E region is notably more depleted in highly incompatible trace elements relative to other regions of the SWIR, although this depletion is not apparent in H2O, which is similarly abundant throughout the SWIR. We link the high H2O/Ce ratios in these glasses with other trace element characteristics diagnostic of subduction and fluid addition, suggesting that the mantle source reflects signatures of a refractory mantle residue that previously melted within a subduction zone.
Observation of Unusual Chorus Elements by Van Allen Probes
Authors: Liu Si , Gao Zhonglei , Xiao Fuliang , He Qian , Li Tong , Shang Xiongjun , Zhou Qinghua , Yang Chang , Zhang Sai
Published: June 2021

Whistler mode chorus waves play an important role in the radiation belt dynamics, which usually appear as discrete elements with frequency sweeping. Finer structure analysis shows that a chorus element is composed of several frequency‐sweeping subelements, and such two‐level structures can be successfully reproduced by modeling based on nonlinear theories. Previous observations and models suggest that an element and its subelements should have the same frequency‐sweep direction. However, we here present two unexpected chorus rising tone events within which the subelements exhibit clearly reversed, falling frequency‐sweep. Moreover, the subelements consist of several wave packets that also show falling frequency‐sweep features. The three‐level structured chorus elements are distinctly different from all the reported observations and seem to bring challenges to the existing theories. We propose a possible scenario that the falling tone subelements are formed by nonlinear process with much shorter timescale and the starting frequency of each subelement is controlled by fast varying electron distribution. This study may inspire more studies toward a thorough understanding of the chorus generation process.
Submarine Meltwater From Nioghalvfjerdsbræ (79 North Glacier), Northeast Greenland
Authors: Huhn Oliver , Rhein Monika , Kanzow Torsten , Schaffer Janin , Sültenfuß Jürgen
Published: June 2021

The Greenland Ice Sheet (GrIS) faces accelerated melting under a warming climate. This also affects the largest marine‐terminating outlet glacier of the Northeast Greenland Ice Stream (NEGIS), the Nioghalvfjerdsbræ (79 North Glacier, 79NG). In the cavity below its floating ice tongue, the heat of inflowing warm and saline Atlantic Water melts the ice at the base, and colder and fresher outflow is exported toward the shelf break and presumably south with the East Greenland Current (EGC). However, freshwater from submarine melting is hardly distinguishable from other freshwater sources by salinity alone. To identify and to quantify the distribution of submarine meltwater on the Northeast Greenland Shelf, we use helium (He) and neon (Ne) observations obtained directly at the calving front of the 79NG, on the Northeast Greenland Shelf, and in Fram Strait during an expedition aboard R/V POLARSTERN in summer 2016. These tracers uniquely identify submarine meltwater (SMW) and allow quantifying its fraction. SMW is present on the shelf but dilutes from 1.8% at the 79NG calving front to nonsignificant in Fram Strait. The SMW formation rate of the 79NG was estimated to be 14.5 ± 2.3 Gt per year. A surplus of Ne compared to He in the upper 100 dbar observed on most of the shelf region is attributed to noble gas fractionation during sea ice formation. Combining the Ne excess with the ventilation time on the shelf of 1.5 years yields a mean sea ice formation rate of 4 m per year.
First Documented Downward Positive Cloud‐to‐Ground Lightning Initiated by an Upward Negative Lightning
Authors: Jiang Ruijiao , Lyu Weitao , Wu Bin , Qi Qi , Chen Lyuwen , Ma Ying , Lyu Fanchao , Zhu Yanan , Rakov Vladimir A.
Published: June 2021

An interesting downward positive cloud‐to‐ground lightning (DPCG) initiated by an upward negative cloud‐to‐ground lightning (UNCG) was recorded by the instruments installed at the Tall‐Object Lightning Observatory in Guangzhou. The characteristics of the discharges before and after the DPCG return stroke were investigated in detail using both optical and electric field change data. The UNCG was triggered from the tip of the Canton Tower (600 m high) by a distant +CG lightning. A sequence of intracloud (IC) discharges developed toward and connected to several pre‐existing channels of the UNCG. As a result, some positive charge was pumped from remote thundercloud regions to the region around the intersection of the pre‐existing and new channels. A branch of one IC channel developed from the intersection point toward the ground, transformed into a downward positive leader, terminated on the ground, and resulted in a positive return stroke. After that, the discharge processes in the cloud continued to neutralize the remaining positive charge. The UNCG served to facilitate the IC discharges that supplied positive charges for the DPCG. Most of the charge involved in the UNCG‐initiated DPCG originated from remote positively charged regions in the cloud. These observations constitute evidence for a new scenario of the initiation of +CG lightning.
Blue Flashes as Counterparts to Narrow Bipolar Events: The Optical Signal of Shallow In‐Cloud Discharges
Authors: Li Dongshuai , Luque Alejandro , Gordillo‐Vázquez F. J. , Liu Feifan , Lu Gaopeng , Neubert Torsten , Chanrion Olivier , Zhu Baoyou , Østgaard Nikolai , Reglero Víctor
Published: June 2021

Narrow Bipolar Events (NBEs) are powerful radio emissions from thunderstorms, which have been recently associated with blue optical flashes on cloud tops and attributed to extensive streamer electrical discharges named fast breakdown. Combining data obtained from a thunderstorm over South China by the space‐based Atmosphere Space Interactions Monitor, the Vaisala GLD360 global lightning network and very low frequency/low frequency radio detectors, here we report and analyze for the first time the optical emissions of blue luminous events associated with negative NBEs and located at the top edge of a thundercloud. These emissions are weakly affected by scattering from cloud droplets, allowing us to estimate the source extension and optical energy involved in the process. The optical energy in the 337‐nm band emitted by fast breakdown is about 104 J, which involves around 109 streamer initiation events.