bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of antler asymmetry with hoof disease in elk
Authors: Wild Margaret A. , Sargeant Glen A. , Garrison Kyle , Conradson Dylan
Published: May 2022

Treponeme‐associated hoof disease (TAHD) is an emergent disease of elk (Cervus canadensis) in the Pacific West of the United States. Although lesions are usually restricted to the feet, anecdotal reports suggested increased prevalence of abnormal antlers in affected elk. We used hunter harvest reports for 1,688 adult male elk harvested in southwestern Washington, USA, during 2016‐2018, to evaluate anecdotal reports. We used Akaike's Information Criterion to compare 18 logistic regression models describing the prevalence of asymmetrical antlers, indicated by unequal antler point counts. Our leading model (84% of model weight) described additive effects of TAHD (odds ratio = 1.91; 95% CI = [1.49, 2.44]) and maximum number of antler points. Confidence intervals overlapped zero for all other parameters, which described ecotypic, geographic, and age‐related effects. Effects of physical injury on antler development have been described elsewhere; however, injuries leading to instances of antler deformity do not have population‐level management implications. In contrast, we describe effects of a transmissible disease that was reported by hunters in >35% of adult male elk and was associated with an increase of ≥16 percentage points in the prevalence of gross asymmetry. Unequal point counts are quite common in elk with otherwise typical antlers and seem unlikely to attract public notice or be attributed to hoof lesions; thus, we suspect our results and anecdotal reports reflect more prominent deformities that are important to stakeholders who enjoy hunting and wildlife viewing.
The scavenger spyglass: how recruiting hunters to watch carrion boosts wildlife research
Authors: McTee Michael , Stone Katharine
Published: May 2022

Hunters support scavengers with seasonal pulses of carrion. If those hunters also deploy remote cameras at kill sites, they could simultaneously contribute data to wildlife research while gaining first‐hand knowledge of scavenger ecology. In 2018–2020, we recruited hunters to monitor carcasses and offal with remote cameras across western Montana, USA. We increased our sampling effort by also setting up cameras following successful elk (Cervus canadensis) hunts at a private ranch. Cameras recorded 19 scavenger species. Golden eagles (Aquila chrysaetos) appeared at 55% of sites, and 3 individuals wore auxiliary markers, demonstrating how hunters can augment efforts to detect tagged wildlife. Cameras also documented elusive predators (e.g., wolves [Canis lupus]) and a seasonality of scavenging among American black bears (Ursus americanus). At 42% of the sites, ≥1 cervid investigated the carrion within 1 m, a behavior that may transmit the prions associated with chronic wasting disease. Hunters are willing and competent citizen scientists that can help generate wildlife observations at a broad spatial scale.
Laryngeal, Pharyngeal and Respiratory Involvement in Palatal Tremor
Authors: Din‐Lovinescu Corina , Blitzer Andrew
Published: May 2022

Objective

To present cases of atypical palatal tremor (PT) and showcase the variable phenomenology of this condition.

Study Design

Retrospective case series.

Results

PT, or palatal myoclonus, is a movement disorder characterized by brief, involuntary rhythmic muscular contractions of the soft palate. Variants of PT have been described and include synchronous tremors in other branchial arch derivatives including the larynx, pharynx, neck, face, jaw, ocular and also respiratory and trunk muscles. We present 3 cases, including clinical videos, of atypical PT with extra‐palatal manifestations, in addition to a brief discussion of the pathophysiology and management of this condition.

Conclusion

Variations of PT are of interest to the practicing otolaryngologist as the clinical spectrum of this condition is wide and can present with laryngeal, pharyngeal, respiratory and other head and neck manifestations.
The effects of Ni availability on H2 production and N2 fixation in a model unicellular diazotroph: The expression of hydrogenase and nitrogenase
Authors: Li Hsin‐Ting , Tuo Sing‐How , Lu Mei‐Chen , Ho Tung‐Yuan
Published: May 2022

We investigated the effects of Ni concentration on hydrogen (H2) net production and nitrogen (N2) fixation rates in a model unicellular diazotrophic cyanobacterium, Cyanothece. We quantified NiFe uptake hydrogenase of the diazotroph to examine how Ni deficiency affects the expression of hydrogenase and nitrogenase and N2 fixation rates. We found that Ni availability controls its H2 net production and the expression of HupL, the major subunit of the uptake hydrogenase. Low Ni availability induced low HupL expression levels while yielding high H2 net production, and vice versa. We also identified the threshold range of Ni concentrations that may differentiate low and high H2 net production patterns in the diazotroph. However, the substantial variations in Ni availability and H2 net production did not affect nitrogenase expression and N2 fixation rates in Cyanothece. From two independent studies in the Atlantic tropical and subtropical oceans, we found that dissolved Ni concentrations and H2 oversaturation percentage exhibited a statistically significant negative correlation, which is consistent with the findings of this culture study. Overall, these results indicate that Ni availability may affect H2 net production and concentrations in the euphotic zone of the oceanic regions. H2 concentrations may be used as a promising proxy to reflect N2 fixation activities in tropical and subtropical oceans only under Ni‐deficient conditions.
Biocatalytic quantification of α‐glucan in marine particulate organic matter
Authors: Steinke Nicola , Vidal‐Melgosa Silvia , Schultz‐Johansen Mikkel , Hehemann Jan‐Hendrik
Published: May 2022

Marine algae drive the marine carbon cycle, converting carbon dioxide into organic material. A major component of this produced biomass is a variety of glycans. Marine α‐glucans include a range of storage glycans from red and green algae, bacteria, fungi, and animals. Although these compounds are likely to account for a high amount of the carbon stored in the oceans they have not been quantified in marine samples so far. Here we present a method to extract and quantify α‐glucans (and compare it with the β‐glucan laminarin) in particulate organic matter from algal cultures and environmental samples using sequential physicochemical extraction and enzymes as α‐glucan‐specific probes. This enzymatic assay is more specific and less susceptible to side reactions than chemical hydrolysis. Using HPAEC‐PAD to detect the hydrolysis products allows for a glycan quantification in particulate marine samples down to a concentration of ≈2 µg/L. We measured glucans in three cultured microalgae as well as in marine particulate organic matter from the North Sea and western North Atlantic Ocean. While the β‐glucan laminarin from diatoms and brown algae is an essential component of marine carbon turnover, our results further indicate the significant contribution of starch‐like α‐glucans to marine particulate organic matter. Henceforth, the combination of glycan‐linkage‐specific enzymes and chromatographic hydrolysis product detection can provide a powerful tool in the exploration of marine glycans and their role in the global carbon cycle.
Dynamics of Nigral Iron Accumulation in Parkinson's Disease: From Diagnosis to Late Stage
Authors: Du Guangwei , Wang Ernest , Sica Christopher , Chen Hairong , De Jesus Sol , Lewis Mechelle M. , Kong Lan , Connor James , Mailman Richard B. , Huang Xuemei
Published: May 2022

Background

Higher nigral iron has been reported in Parkinson's disease (PD).

Objective

The aim is to understand the dynamics of nigral iron accumulation in PD and its association with drug treatment.

Methods

Susceptibility magnetic resonance imaging data were obtained from 79 controls and 18 drug‐naive (PDDN) and 87 drug‐treated (PDDT) PD patients. Regional brain iron in basal ganglia and cerebellar structures was estimated using quantitative susceptibility mapping. Nigral iron was compared between PDDN and PDDT subgroups defined by disease duration (early [PDE, <2 years], middle [PDM, 2–6 years], and later [PDL, >6 years]). Associations with both disease duration and types of antiparkinson drugs were explored using regression analysis.

Results

Compared to controls, PDDN had lower iron in the substantia nigra (P = 0.018), caudate nucleus (P = 0.038), and globus pallidus (P = 0.01) but not in the putamen or red nucleus. In contrast, PDDT had higher iron in the nigra (P < 0.001) but not in other regions, compared to either controls or PDDN. Iron in the nigra increased with disease duration (PDE > PDDN [P = 0.001], PDM > PDE [P = 0.045]) except for PDM versus PDL (P = 0.226). Levodopa usage was associated with higher (P = 0.013) nigral iron, whereas lower nigral iron was correlated with selegiline usage (P = 0.030).

Conclusion

Nigral iron is lower before the start of dopaminergic medication and then increases throughout the disease until it plateaus at late stages, suggesting increased iron may not be an etiological factor. Interestingly, PD medications may have differential associations with iron accumulation that need further investigation. © 2022 International Parkinson and Movement Disorder Society.
Molecular heterogeneity of β‐thalassemia variants in the Eastern region of Morocco
Authors: Belmokhtar Ihab , Lhousni Saida , Elidrissi Errahhali Mounia , Ghanam Ayad , Elidrissi Errahhali Manal , Sidqi Zaina , Ouarzane Meryem , Charif Majida , Bellaoui Mohammed , Boulouiz Redouane , Benajiba Noufissa
Published: May 2022

Background

β‐thalassemia syndromes are the most common hereditary blood disorders in the world and are recognized as a major health problem in Morocco. They are characterized by the reduction or the absence of β‐globin chain synthesis. The severity of the disease depends on the nature of the variants affecting the β‐globin gene (HBB), and each ethnic group has its own mutation spectrum. Hereby, we present, for the first time, the molecular profile of β‐thalassemia in the Eastern region of Morocco.

Methods

This study concerns 39 cases from 33 families who were enrolled in the BRO Biobank. Nineteen were diagnosed with β‐thalassemia major and 20 with β‐thalassemia minor. To detect mutations of the β‐globin gene, we have used RFLP‐PCR and Sanger sequencing.

Results

Nine known β‐thalassemia variants have been identified. Among these, we reported, for the first time in the Moroccan population, the Czechoslovakian variant C38/39(‐C) at homozygous state. The C39(C > T) was the most frequent variant (72.54%), followed by FSC5(‐CT) (5.88%), FSC6(−A), IVS‐1‐110(G > A), −29(A > G), C38/39(‐C) (3.92% each), and finally by IVS‐I‐1(G > A), IVS‐II‐1(G > A), and −56(G > C) (1.96%). Of particular interest this mutational spectrum of β‐thalassemia is very different from that found in previous studies in Morocco or in other North African countries.

Conclusion

This study is the first contribution to the description of the molecular profile of β‐thalassemia in the Eastern region of Morocco. It shows the high molecular heterogeneity of β‐thalassemia in our country. Therefore, these results can be valuable for the implementation of carrier screening, genetic counseling, and prenatal diagnosis programs.
Intestinal Flora Mediates Antiobesity Effect of Rutin in High‐Fat‐Diet Mice
Authors: Yan Xu , Zhai Yuanyuan , Zhou Wenling , Qiao Yuan , Guan Lingling , Liu Hao , Jiang Jizhi , Peng Liang
Published: May 2022

Scope

Intestinal flora plays a critical role in the development of . Rutin is a natural flavonoid with potential prebiotic effects on regulating the intestinal flora composition that is beneficial for host health. Therefore, this study hypothesizes that rutin supplementation has beneficial effects on high‐fat‐diet (HFD)‐induced obesity and metabolic disorder through the modulation of intestinal flora in mice.

Methods and results

The obesity‐alleviating property of rutin using 6‐week‐old C57BL/6J male mice fed on HFD with or without rutin supplementation for 16 weeks is investigated. Rutin supplementation effectively reduces body‐weight gain, insulin resistance, and acted favorably on the intestinal barrier, thereby reducing endotoxemia and systemic inflammation. Sequencing of 16S rRNA genes from fecal samples indicate that rutin exerted modulatory effects on HFD‐induced intestinal flora disorders (e.g., rutin decreased Firmicutes abundance and increased Bacteroidetes and Verrucomicrobia abundance). Antibiotic treatment and fecal microbiota transplantation further demonstrate that the salutary effects of rutin on obesity control are strongly dependent on the intestinal flora.

Conclusion

Rutin can be considered as a prebiotic agent for improving intestinal flora disorders and obesity‐associated metabolic perturbations in obese individuals.
Functional Fermented Probiotics, Prebiotics, and Synbiotics from Non‐Dairy Products: A Perspective from Nutraceutical
Authors: Kumar Dharmendra , Lal Milan Kumar , Dutt Som , Raigond Pinky , Changan Sushil Sudhakar , Tiwari Rahul Kumar , Chourasia Kumar Nishant , Mangal Vikas , Singh Brajesh
Published: May 2022

The current trend of health‐conscious consumers and healthy food habits prompts researchers to explore developing food products with synbiotic benefits. Synbiotic foods have gained popularity in recent years due to their functional, nutritional, physiological, and therapeutic characteristics. Lactose intolerance, dyslipidemia, and allergic milk proteins become the barriers in the development of dairy probiotics. The present scenario of an increase in the demand for vegetarian products leads to a rise in the consumption of non‐dairy probiotics. Prebiotics like, resistant starch, inulin, and polyphenols are selectively used by gut microbiota to enhance the selection and colonization of probiotics bacteria. Probiotic's action mechanisms include the production of bacteriocins, peptides, short‐chain fatty acids, amino acids, vitamins, and other metabolites. Therefore, this review article explores the alternative sources of probiotics so it will help to an understanding of non‐dairy based functional fermented foods for both pro and prebiotics. Dietary fibers in vegetables, fruits, and cereals are one of prospective prebiotics and highlighted the various methods for making non‐dairy synbiotics based on dietary fibers, such as microencapsulation, freeze‐drying, and spray drying is also addressed.
An incremental‐secant mean‐field homogenization model enhanced with a non‐associated pressure‐dependent plasticity model
Authors: Calleja Vázquez Juan Manuel , Wu Ling , Nguyen Van‐Dung , Noels Ludovic
Published: May 2022

This article introduces a, possibly damage‐enhanced, pressure‐dependent‐based incremental‐secant mean‐field homogenization (MFH) scheme for two‐phase composites. The incremental‐secant formulation consists on a fictitious unloading of the material up to a stress‐free state, in which a residual stress is attained in its phases. Then the secant method is performed in order to compute the mean stress fields of each phase. One of the main advantages of this method is the natural isotropicity of the secant tensors that allows defining the linear‐comparison‐composite (LCC). In this work, we show that this isotropic nature is preserved for a non‐associated pressure dependent plastic flow, making possible the direct definition of the LCC. This model is thus able to represent the physics of real polymeric composites. The MFH scheme is then verified by testing its prediction capabilities in several cases, including cyclic and nonproportional loading involving perfectly elastic phases, elasto‐plastic and damage‐enhanced elasto‐plastic phases in random representative volume elements (RVE) of uni‐directional (UD) composites and of composites reinforced with spherical inclusions.
Flame‐retardant polyamide 56 with high fire safety and good thermal performance
Authors: Yang Tingting , Gao Yuanbo , Liu Xiucai , Wang Xueli , Ma Bomou , He Yong
Published: May 2022

As a recently developed biobased polyamide, polyamide 56 (PA56) has great potential in the field of fibers and textiles due to its high strength, high moisture absorption, and easy dyeing. However, the application of PA56 is restricted due to its flammability. Flame‐retardant PA56 copolymers (FRPA56s) have been designed and successfully synthesized by the introduction of 2‐carboxyethyl(phenyl)phosphinic acid (CEPPA) monomer. The thermal properties and thermal stability of FRPA56s have been evaluated using DSC and TGA, respectively. The flammability behavior of the resultant copolymer has been investigated using UL94 vertical burning and cone calorimetry tests. The crystallization temperature (Tc), melting temperature (Tm), and crystallinity (Xc) of FRPA56s are reduced and the degradation pathway for PA56 is changed with the introduction of CEPPA. In addition, FRPA56 containing 7.8 mol% CEPPA may be characterized by a V‐0 rating in the UL94 vertical burning test and its total heat release is reduced 20% than that of PA56, reflecting the high flame‐retardant efficiency of CEPPA. Based on the analysis of the residual char and the gas‐phase pyrolysis products for combustion of FRPA56s, it is concluded that the flame‐retardant modes of action for this material mainly include flame inhibition, dilution effect and charring.
Investigation of 3‐aminopropyltrimethoxysilane for direct deposition of thin films containing primary amine groups by open‐air plasma jets
Authors: Morand Gabriel , Guyon Cédric , Chevallier Pascale , Saget Manon , Semetey Vincent , Mantovani Diego , Tatoulian Michael
Published: May 2022

Open‐air plasma jets are becoming increasingly popular due to easy and affordable large‐scale coating deposition on diverse substrates. However, direct deposition of primary amine groups (NH2), which are attractive as covalent anchor points for molecule grafting, remains challenging. In this study, 3‐aminopropyltrimethoxysilane (APTMS) has been directly polymerized on glass by a plasma jet. Quantification of NH2 showed that APTMS polymerization and NH2 degradation were correlated with Yasuda's parameter and that a compromise between NH2 retention and coating stability is required. Evaporation of APTMS was found to improve surface smoothness and homogeneity but was found to decrease the deposited NH2 concentration, from 3.7 ± 1.3 NH2/nm2 to three times lower. Results showed that deposited NH2 could be used as anchor points for polyethylene glycol chain immobilization.
Segmentation of vegetation and microplots in aerial agriculture images: A survey
Authors: Mardanisamani Sara , Eramian Mark
Published: May 2022

Because of the increasing global population, changing climate, and consumer demands for safe, environmentally friendly, and high‐quality food, plant breeders strive for higher yield cultivars by monitoring specific plant phenotypes. Developing new crop cultivars and monitoring through current methods is time‐consuming, sometimes subjective, and based on subsampling of microplots. High‐throughput phenotyping using unmanned aerial vehicle‐acquired aerial orthomosaic images of breeding trials improves and simplifies this labor‐intensive process. To perform per‐microplot phenotype analysis from such imagery, it is necessary to identify and localize individual microplots in the orthomosaics. This paper reviews the key concepts of recent studies and possible future developments regarding vegetation segmentation and microplot segmentation. The studies are presented in two main categories: (a) general vegetation segmentation using vegetation‐index‐based thresholding, learning‐based, and deep‐learning‐based methods; and (b) microplot segmentation based on machine learning and image processing methods. In this study, we performed a literature review to extract the algorithms that have been developed in vegetation and microplots segmentation studies. Based on our search criteria, we retrieved 92 relevant studies from five electronic databases. We investigated these selected studies carefully, summarized the methods, and provided some suggestions for future research.
Poor early childhood growth is associated with impaired lung function: Evidence from a Ghanaian pregnancy cohort
Authors: Kaali Seyram , Jack Darby W. , Prah Rebecca K. D. , Chillrud Steven N. , Mujtaba Mohammed N. , Kinney Patrick L. , Tawiah Theresa , Yang Qiang , Oppong Felix B. , Gould Carlos F. , Osei Musah , Wylie Blair J. , Agyei Oscar , Perzanowski Matthew S. , Asante Kwaku Poku , Lee Alison G.
Published: May 2022

Objectives

Nearly 40% of African children under 5 are stunted. We leveraged the Ghana randomized air pollution and health study (GRAPHS) cohort to examine whether poorer growth was associated with worse childhood lung function.

Study Design

GRAPHS measured infant weight and length at birth and 3, 6, 9,12 months, and 4 years of age. At age 4 years, n = 567 children performed impulse oscillometry. We employed multivariable linear regression to estimate associations between birth and age 4 years anthropometry and lung function. Next, we employed latent class growth analysis (LCGA) to generate growth trajectories through age 4 years. We employed linear regression to examine associations between growth trajectory assignment and lung function.

Results

Birth weight and age 4 weight‐for‐age and height‐for‐age z‐scores were inversely associated with airway resistance (e.g., R5, or total airway resistance: birth weight β = −0.90 cmH2O/L/s, 95% confidence interval [CI]: −1.64, −0.16 per 1 kg increase; and R20, or large airway resistance: age 4 height‐for‐age β = −0.40 cmH2O/L/s, 95% CI: −0.57, −0.22 per 1 unit z‐score increase). Impaired growth trajectories identified through LCGA were associated with higher airway resistance, even after adjusting for age 4 body mass index. For example, children assigned to a persistently stunted trajectory had higher R5 (β = 2.71 cmH2O/L/s, 95% CI: 1.07, 4.34) and R20 (β = 1.43 cmH2O/L/s, 95% CI: 0.51, 2.36) as compared to normal.

Conclusion

Children with poorer anthropometrics through to age 4 years had higher airway resistance in early childhood. These findings have implications for lifelong lung health, including pneumonia risk in childhood and reduced maximally attainable lung function in adulthood.
Time Resolved‐Fluorescence Resonance Energy Transfer platform for quantitative nucleosome binding and footprinting
Authors: Wesley Nathaniel A. , Skrajna Aleksandra , Simmons Holly C. , Budziszewski Gabrielle R. , Azzam Dalal N. , Cesmat Andrew P. , McGinty Robert K.
Published: May 2022

Quantitative analysis of chromatin protein–nucleosome interactions is essential to understand regulation of genome‐templated processes. However, current methods to measure nucleosome interactions are limited by low throughput, low signal‐to‐noise, and/or the requirement for specialized instrumentation. Here, we report a Lanthanide Chelate Excite Time‐Resolved Fluorescence Resonance Energy Transfer (LANCE TR‐FRET) assay to efficiently quantify chromatin protein–nucleosome interactions. The system makes use of commercially available reagents, offers robust signal‐to‐noise with minimal sample requirements, uses a conventional fluorescence microplate reader, and can be adapted for high‐throughput workflows. We determined the nucleosome‐binding affinities of several chromatin proteins and complexes, which are consistent with measurements obtained through orthogonal biophysical methods. We also developed a TR‐FRET competition assay for high‐resolution footprinting of chromatin protein–nucleosome interactions. Finally, we set up a TR‐FRET competition assay using the LANA peptide to quantitate nucleosome acidic patch binding. We applied this assay to establish a proof‐of‐principle for regulation of nucleosome acidic patch binding by methylation of chromatin protein arginine anchors. Overall, our TR‐FRET assays allow facile, high‐throughput quantification of chromatin interactions and are poised to complement mechanistic chromatin biochemistry, structural biology, and drug discovery programs.
Lifetime Assessment of InxGa1−xAs n‐Type Hetero‐Epitaxial Layers
Authors: Hsu P.-C. (Brent) , Simoen Eddy , Eneman Geert , Merckling Clement , Mols Yves , Heyns Marc
Published: May 2022

Herein, the carrier lifetime in ≈5 × 1016 cm−3 n‐doped InxGa1−xAs layers is studied by diode current–voltage analysis and by time‐resolved photoluminescence. Two sets of hetero‐epitaxial layers are grown on semi‐insulating InP or GaAs substrates. The first set corresponds with a constant In content p + n stack, while the second set has a fixedx = 0.53 for the n‐layer, while containing various extended defect densities by using a strain relaxed buffer with differentx. This results in threading dislocation densities (TDDs) between ≈105 cm−2and a few 109 cm−2. It is shown that the overall trend of the recombination lifetime versus TDD can be described by a first‐order model considering a finite recombination lifetime value inside a dislocation core of 1 nm. For the generation lifetime, a strong electric‐field enhancement factor is found. Also, the residual strain in the n‐layer has an impact. Overall, the safe limit for TDD depends on the type of application and on the operation conditions (reverse diode bias).
Polydatin as a therapeutic alternative for central nervous system disorders: A systematic review of animal studies
Authors: Schimith Lucia E. , dos Santos Michele G. , Arbo Bruno D. , André‐Miral Corinne , Muccillo‐Baisch Ana L. , Hort Mariana A.
Published: May 2022

Polydatin, or piceid, is a natural stilbene found in grapes, peanuts, and wines. Polydatin presents pharmacological activities, including neuroprotective properties, exerting preventive and/or therapeutic effects in central nervous system (CNS) disorders. In the present study, we summarize and discuss the neuroprotective effects of polydatin in CNS disorders and related pathological conditions in preclinical animal studies. A systematic review was performed by searching online databases, returning a total of 110 records, where 27 articles were selected and discussed here. The included studies showed neuroprotective effects of polydatin in experimental models of neurological disorders, including cerebrovascular disorders, Parkinson's disease, traumatic brain injuries, diabetic neuropathy, glioblastoma, and neurotoxicity induced by chemical agents. Most studies were focused on stroke (22.2%) and conducted in male rodents. The intervention protocol with polydatin was mainly acute (66.7%), with postdamage induction treatment being the most commonly used regimen (55.2%). Overall, polydatin ameliorated behavioral dysfunctions and/or promoted neurological function by virtue of its antioxidant and antiinflammatory properties. In summary, this review offers important scientific evidence for the neuroprotective effects and distinct pharmacological mechanisms of polydatin that not only enhances the present understanding but is also useful for the development of future preclinical and clinical investigations.
Formation of maritime convergence zones within cold air outbreaks due to the shape of the coastline or sea ice edge
Authors: Watanabe Shun‐ichi I. , Niino Hiroshi , Spengler Thomas
Published: May 2022

Maritime cold air outbreaks often feature convergence zones that provide a conducive environment for the development of polar mesoscale cyclones and polar lows. This study examines the formation mechanisms of these convergence zones in cold air outbreaks downstream of a coastline or sea‐ice edge. A simplified configuration in which the coastline or sea‐ice edge is approximated by a line featuring a bend with an angle is examined using analytic solutions and idealised numerical simulations. The bend of the coastline causes differences in the fetch over which air parcels travel, causing a warm wedge of air downstream of the bend due to differential airmass transformations. The warm wedge is associated with a pressure trough that leads to convergence in the presence of surface friction. The analytic model captures this mechanism and compares well with the idealised numerical simulations. Condensational heating associated with moist convection enhances vertical motions and thus intensifies the horizontal convergence. The idealised numerical simulations also reproduce an asymmetry in the vertical shear of the horizontal wind across the convergence zone, which explains the transverse cloud streets downstream to the left of the convergence zone.
Value‐iteration‐based affine nonlinear optimal control involving admissibility discussion
Authors: Wang Ding , Ren Jin , Ha Mingming
Published: May 2022

In this article, the admissibility analysis of the value‐iteration‐based control policy is investigated for affine nonlinear dynamics. First, a series of admissible control criteria are discussed for nonlinear and linear systems. With the help of these criteria, it is more convenient to determine whether an iterative control policy is admissible or not compared with the previous work. Second, once the iterative control policy is established to be admissible by the criteria, the stability of the closed‐loop systems using the control law can be guaranteed. In addition, under certain conditions, the admissibility and asymptotic stability similar to policy iteration can be obtained. Finally, two numerical examples with the physical background are afforded to validate the effectiveness of presented theoretical results.
Trajectory tracking for quadrotors: An optimization‐based planning followed by controlling approach
Authors: Kulathunga Geesara , Devitt Dmitry , Klimchik Alexandr
Published: May 2022

We present an optimization‐based reference trajectory tracking method for quadrotor robots for slow‐speed maneuvers. The proposed method uses planning followed by the controlling paradigm. The basic concept of the proposed method is an analogy with linear quadratic Gaussian in which nonlinear model predictive control (NMPC) is employed for predicting optimal control policy in each iteration. Multiple‐shooting is suggested over direct‐collocation for imposing constraints when modeling the NMPC. Incremental Euclidean distance transformation map is constructed for obtaining the closest free distances relative to the predicted trajectory; these distances are considered obstacle constraints. The reference trajectory is generated ensuring dynamic feasibility. The objective is to minimize the error between the quadrotor's current pose and the desired reference trajectory pose in each iteration. Finally, we compared the proposed method with two other approaches and showed that the proposed method outperforms the said approaches in terms of reaching the goal without any collision. Additionally, we published a new data set that can be used for evaluating the performance of trajectory tracking algorithms.
Pattern‐orientedanalysis of system dynamics models via random forests
Authors: Edali Mert
Published: May 2022

System dynamics (SD) modeling studies aim to reveal the causes of problematic dynamic behaviors and eliminate them through policy design and analysis. The analyst conducts sensitivity/scenario analyses and what‐if experiments to reveal the input–output relationships during modeling. However, during these analyses and investigations, the identification of input‐parameter spaces that cause the generation of different SD model behavior patterns is time consuming and susceptible to human bias. Therefore, we propose a metamodel‐based procedure for SD models that considers the necessity for unbiased and automated analysis and insight generation. The approach uses the random forest algorithm for metamodel generation and extracts interpretable IF–THEN rules from the metamodel, thereby identifying input subspaces that generate different qualitative or numerical SD model outputs. We illustrate the proposed approach using two well‐established SD models. These case studies reveal how the model analyst can utilize the proposed method to capture input–output relationships. © 2022 System Dynamics Society.
Breakthrough invention and problem complexity: Evidence from a quasi‐experiment
Authors: Zhang Yuchen , Yang Wei
Published: May 2022

Research Summary

Problem formulation is central to recombinant invention, and problem complexity particularly shapes the process and outcome of knowledge recombination. However, research on the antecedents of problem complexity remains limited. This study examines how breakthrough inventions may serve as an important antecedent of the complexity of problems formulated by individual inventors. We propose that a breakthrough invention may facilitate inventors' appreciation of novel knowledge couplings and improve their overall comprehension of knowledge interdependence for problem formulation, thus increasing problem complexity. We further argue that inventors' prior search breadth and experimentation strengthen the above effect. By exploiting the unexpected victory of AlphaGo and tracking the questions posted on StackOverflow.com by developers interested in deep learning, we find empirical evidence that supports our hypotheses.

Managerial Summary

Because formulating complex problems may result in novel and valuable inventions, it is helpful to understand what drives inventors to formulate problems of higher complexity. In this study, we propose that breakthrough inventions can serve as an important antecedent of problem complexity. In the context of deep learning, we find that developers formulate problems of higher complexity after the unexpected victory of AlphaGo, a widely acknowledged inventive breakthrough. Further, the above effect is more pronounced when developers have broad search experience in the past or engage frequently in experimentation. The insights of this study are not only relevant to managerial practices within the dynamic field of deep learning but also generalizable to broader technological contexts with breakthrough inventions.
How do managers evaluate individual contributions to team production? A theory and empirical test
Authors: Uribe Jose , Carnahan Seth , Meluso John , Austin‐Breneman Jesse
Published: May 2022

Research Summary

Organizations rely on subjective evaluations to reward employees for team‐based performance. However, it is unclear how supervisors determine individuals' contributions to collective output. We theorize that supervisors rely on the covariance between employees' presence and their teams' productivity. If teams are more productive when an employee is present, the supervisor may infer a greater contribution from the employee. Using data from a manufacturing firm, we find that covariation between an employee's presence and her team's output has a positive effect on her evaluation. This relationship is stronger when supervisors have more opportunities to observe an employee across various teams and when the employee has more authority to direct team production, supporting counterfactual information as an important component of evaluations for individuals engaged in team production.

Managerial Summary

It is notoriously difficult to evaluate the individual performance of employees when the only available metric is team‐based output. We suggest that supervisors help solve this problem by observing how team output correlates with changes in team membership. We construct a measure of the covariance between an employee's presence in a team and the team's productivity, and find a positive relationship between this measure and the employee's annual subjective performance evaluation. Our results indicate that subjective evaluations reflect individual contributions to team production fairly well for employees who (a) have sufficient authority to direct team production and (b) are frequently rotated beyond a single team. We discuss what kinds of organizations might benefit from this measure as an input to their performance evaluation processes.
Engineering the Non‐Radiative Recombination of Mixed‐Halide Perovskites with Optimal Bandgap for Indoor Photovoltaics
Authors: Li Yanyan , Li Ruiming , Lin Qianqian
Published: May 2022

Indoor photovoltaics have attracted increasing attention, since they can provide sustainable energy through the recycling of photon energy from household dim lighting. However, solar cells exhibiting high performance under sunlight may not perform well under indoor light conditions, mainly due to the mismatch of the irradiance spectrum. In particular, most of the indoor light sources emit visible photons with negligible near‐infrared irradiance. According to the detailed balance theory, the optimal bandgap for indoor photovoltaics should be relatively larger, considering the trade‐off between photocurrent and photovoltage losses. In this work, a systematic comparison of the theoretical limits of the conventional and indoor photovoltaics is presented. Then the non‐radiative recombination losses are reduced by a synergetic treatment with Pb(SCN)2 and PEABr, resulting relatively high open circuit voltage of 1.29 V and power conversion efficiency of 17.32% under 1 sun illumination. Furthermore, the devices are fully characterized under weak indoor light (1000 lux, 4000 K LED) achieving a high efficiency of 37.18%, which is promising for real applications.
Machine learning‐based test oracles for performance testing of cyber‐physical systems: An industrial case study on elevators dispatching algorithms
Authors: Gartziandia Aitor , Arrieta Aitor , Ayerdi Jon , Illarramendi Miren , Agirre Aitor , Sagardui Goiuria , Arratibel Maite
Published: May 2022

The software of systems of elevators needs constant maintenance to deal with new functionality, bug fixes, or legislation changes. To automatically validate the software of these systems, a typical approach in industry is to use regression oracles, which execute test inputs both in the software version under test and in a previous software version. However, these practices require a long test execution time and cannot be re‐used at different test phases. To deal with these issues, we propose Dispatching AlgoRIthm Oracle (DARIO), a test oracle that relies on regression machine‐learning algorithms to detect both functional and non‐functional problems of the system. The machine‐learning algorithms of this oracle are trained by using data from previously tested versions to predict reference functional and non‐functional performance values of the new versions. An empirical evaluation with an industrial case study demonstrates the feasibility of using our approach. A total of five regression learning algorithms were validated by using mutation testing techniques. For the context of functional bugs, the accuracy when predicting verdicts by DARIO ranged between 95% and 98%, across the different scenarios proposed. For the context of non‐functional bugs, were competitive too, having an accuracy when predicting verdicts by DARIO ranged between 83% and 87%.
Anisotropic Charge Transport Enabling High‐Throughput and High‐Aspect‐Ratio Wet Etching of Silicon Carbide
Authors: Shi Dachuang , Chen Yun , Li Zijian , Dong Shankun , Li Liyi , Hou Maoxiang , Liu Huilong , Zhao Shenghe , Chen Xin , Wong Ching‐Ping , Zhao Ni
Published: May 2022

Wet etching of silicon carbide typically exhibits poor etching efficiency and low aspect ratio. In this study, an etching structure that exploits anisotropic charge carrier flow to enable high‐throughput, external‐bias‐free wet etching of high‐aspect‐ratio SiC micro/nano‐structures is demonstrated. Specifically, by applying a catalytic metal coating at the bottom surface of a SiC wafer while introducing patterned ultraviolet light illumination from its top surface, spatial charge separation across the wafer is achieved, i.e., photogenerated electrons are channeled to the bottom to participate in the reduction reaction of an oxidant in the etchant solution, while holes flow to the top to trigger oxidation of SiC and subsequent etching. Such design largely suppresses recombination‐induced charge losses, and when used in combination with a top metal catalyst mask, the structure yields a remarkable vertical etching rate of 0.737 µm min−1 and an aspect ratio of 3.2, setting new records for wet‐etching methods for SiC.
The relationship between inbound open innovation and the innovative use of information technology by individuals in teams of start‐ups
Authors: Yao Meifang , Ye Dan , Zhao Liyi
Published: May 2022

Digital technology and artificial intelligence technology have built an open sharing environment of intellectualization. For start‐ups, which are restricted by their own limited resources, it is wise to take inbound open innovation as a strategy to get external advanced technical information quickly. However, how to match technology resources obtained from outside with the organisation's demand is still a problem for entrepreneurial teams and entrepreneurial researchers. Based on the literature review of existing research and considering entrepreneurial teams' demand to deal with the challenges, this paper firstly analyses the relationship between entrepreneurial teams' inbound open innovation strategy and the innovative use of information technology by individuals in teams of start‐ups and based on the Identity Theory to explore the mechanism of IT identity on the relationship mentioned above. Lastly, the paper further analyses two types of team authorisation (structural empowerment and psychological empowerment) that play different moderating roles in the relationship of inbound open innovation, IT identity and the innovative use of information technology by individuals in teams. Using 238 survey data from entrepreneurial teams with linear regression analysis, we found that IT identity moderates the relationship between inbound open innovation and individual new IT technology exploration positively, and team psychological empowerment has further moderated the relationship between inbound open innovation and the innovative use of information technology by individuals in teams positively, while team structure empowerment plays an inverted U‐shaped moderation. This study has certain guiding significance for entrepreneurial teams to take advantage of digitalised opportunities, and it also has important value for innovation and digitalisation research.
Numerical Simulation of Multiphase Flow in Steel Continuous Casting Mold Using a Novel Euler–Euler–Lagrange Method
Authors: Lai Qingrui , Luo Zhiguo , Zhang Yongjie , You Yang , Zou Zongshu
Published: May 2022

Herein, a new Euler–Euler–Lagrange hybrid method is used to simulate the liquid–solid–gas three‐phase flow in a continuous casting mold. In the used method, bubble coalescence and breakup, inclusion aggregation, bubble–inclusion interaction, and complex force balance of bubbles near the solidification front are simultaneously considered. The predicted inclusion size distribution is in good agreement with previous industrial test results. With the application of this method, inclusions can be tracked even if they are collected by bubbles. This characteristic is useful in the study of harmful phenomena in that bubbles are captured by the solidification front after collecting numerous inclusions. Herein, the effects of various simulation factors on results are studied. The descending order of importance of the simulation factors is as follows: bubble–inclusion interaction, bubble coalescence and breakup, and inclusion aggregation. Ignoring any of these factors underestimates the inclusion removal rate and increases the prediction deviation of the inclusion size distribution. Although inclusion aggregation has little effect on the overall removal fraction, it is the most important way to remove small inclusions with a maximum size of 14.14 μm under the conditions of this research.
Microstructure of Ultrafine Acicular Bainite and Mechanical Properties of 3Cr2MnNiMo Mold Steel during Austempering
Authors: Ren Jinyi , Li Changsheng , Tu Xingyang , Shao Zhibao
Published: May 2022

Herein, the effect of austempering treatment on martensite/bainite multiphase microstructure evolution and mechanical properties of 3Cr2MnNiMo mold steel are investigated, and the mechanical properties are compared with the conventional quenching and tempering (QT) treatment. It indicated that the morphology of martensite/bainite can be effectively tailored by changing the austempering temperature. With the increase of temperature from 280 to 360 °C, the microstructure changes from tempered martensite + bainite + blocky retained austenite (RA) to martensite + coarse bainite plate + blocky RA and irregular martensite/austenite (M/A) island. When the temperature reaches 420 °C, the martensite content reaches the maximum. The bainite morphology is surprisingly transformed from coarse bainite plate to ultrafine acicular shape owing to the reduction of the bainitic driving force and the sharp increase of carbon diffusion coefficient. Moreover, blocky RA and M/A islands disappear and are replaced by nanoscale filmy RA. The alternating distribution of variants has a refinement effect on the microstructure and the effective grain size reaches a minimum value. Compared with the conventional QT treatment, the tensile strength of austempering at 420 °C increased by 702 MPa, but the toughness and ductility levels are almost the same.
Effect of Types of Calcium‐Containing Cored Wires on the Inclusion Modification by Calcium Treatment
Authors: Wu Songjie , Zhang Yanhui , Yang Wen , Zhang Lifeng
Published: May 2022

Calcium treatment experiments with equal calcium amounts using different calcium‐containing cored wires are carried out in the laboratory to investigate the effect of calcium wire types on the modification of inclusions. Inclusions change from Al2O3(–MgO) to calcium aluminates with the feeding of calcium wires; however, the modification degrees are different. The CaO content in inclusions increases to 25.8, 34.5, and 31.0 wt%, respectively, at 1 min after the addition of pure Ca, SiCa, and AlCa. The calcium yield is the highest when using SiCa wire and is the lowest under the use of pure Ca wire. The difference in calcium yield is attributed to the increasing effect of Si or Al on the solubility of calcium in molten steel. When calcium treatment is performed using SiCa and AlCa wires, the local Si and Al content around calcium bubbles would be large, which can promote the dissolution of calcium into steel and increase the yield of calcium. From the perspective of improving calcium yield, calcium treatment with SiCa or AlCa wires is better than that with pure Ca wires. However, steel grade, ladle capacity, and calcium treatment parameters should be further considered in the actual selection of calcium‐containing cored wires.
Adaptive Morphological Filter for Extracting Features of Fault on Transmission Line
Authors: Luo XiaoJie , Zhang LuLiang
Published: May 2022

This letter proposes an adaptive feature extraction method based on mathematical morphology for fault detection and location on transmission line. Multi‐scale morphological operation is designed where triangular structural elements are employed with the heights adjusted adaptively according to the input signal. Extensive simulation studies were carried out under different fault conditions, and the results demonstrated the effectiveness of the proposed method. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.