bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abdominal T2‐Weighted Imaging and T2 Mapping Using a Variable Flip Angle Radial Turbo Spin‐Echo Technique
Authors: Keerthivasan Mahesh B. , Galons Jean‐Philippe , Johnson Kevin , Umapathy Lavanya , Martin Diego R. , Bilgin Ali , Altbach Maria I. 
Published: July 2021

BackgroundT2 mapping is of great interest in abdominal imaging but current methods are limited by low resolution, slice coverage, motion sensitivity, or lengthy acquisitions.PurposeDevelop a radial turbo spin‐echo technique with refocusing variable flip angles (RADTSE‐VFA) for high spatiotemporal T2 mapping and efficient slice coverage within a breath‐hold and compare to the constant flip angle counterpart (RADTSE‐CFA).Study TypeProspective technical efficacy.SubjectsTesting performed on agarose phantoms and 12 patients. Focal liver lesion classification tested on malignant (N = 24) and benign (N = 11) lesions.Field Strength/Sequence1.5 T/RADTSE‐VFA, RADTSE‐CFA.AssessmentA constrained objective function was used to optimize the refocusing flip angles. Phantom and/or in vivo data were used to assess relative contrast, T2 estimation, specific absorption rate (SAR), and focal liver lesion classification.Statistical Testst‐Tests or Mann–Whitney Rank Sum tests were used.ResultsPhantom data did not show significant differences in mean relative contrast (P = 0.10) and T2 accuracy (P = 0.99) between RADTSE‐VFA and RADTSE‐CFA. Adding noise caused T2 overestimation predominantly for RADTSE‐CFA and low T2 values. In vivo results did not show significant differences in mean spleen‐to‐liver (P = 0.62) and kidney‐to‐liver (P = 0.49) relative contrast between RADTSE‐VFA and RADTSE‐CFA. Mean T2 values were not significantly different between the two techniques for spleen (T2VFA = 109.2 ± 12.3 msec; T2CFA = 110.7 ± 11.1 msec; P = 0.78) and kidney‐medulla (T2VFA = 113.0 ± 8.7 msec; T2CFA = 114.0 ± 8.6 msec; P = 0.79). Liver T2 was significantly higher for RADTSE‐CFA (T2VFA = 52.6 ± 6.6 msec; T2CFA = 60.4 ± 8.0 msec) consistent with T2 overestimation in the phantom study. Focal liver lesion classification had comparable T2 distributions for RADTSE‐VFA and RADTSE‐CFA for malignancies (P = 1.0) and benign lesions (P = 0.39). RADTSE‐VFA had significantly lower SAR than RADTSE‐CFA increasing slice coverage by 1.5.Data ConclusionRADTSE‐VFA provided noise‐robust T2 estimation compared to the constant flip angle counterpart while generating T2‐weighted images with comparable contrast. The VFA scheme minimized SAR improving slice efficiency for breath‐hold imaging.Level of Evidence2Technical Efficacy Stage1
Unconventional animal models for traumatic brain injury and chronic traumatic encephalopathy
Authors: Ackermans Nicole L. , Varghese Merina , Wicinski Bridget , Torres Joshua , De Gasperi Rita , Pryor Dylan , Elder Gregory A. , Gama Sosa Miguel A. , Reidenberg Joy S. , Williams Terrie M. , Hof Patrick R. 
Published: July 2021

AbstractTraumatic brain injury (TBI) is one of the main causes of death worldwide. It is a complex injury that influences cellular physiology, causes neuronal cell death, and affects molecular pathways in the brain. This in turn can result in sensory, motor, and behavioral alterations that deeply impact the quality of life. Repetitive mild TBI can progress into chronic traumatic encephalopathy (CTE), a neurodegenerative condition linked to severe behavioral changes. While current animal models of TBI and CTE such as rodents, are useful to explore affected pathways, clinical findings therein have rarely translated into clinical applications, possibly because of the many morphofunctional differences between the model animals and humans. It is therefore important to complement these studies with alternative animal models that may better replicate the individuality of human TBI. Comparative studies in animals with naturally evolved brain protection such as bighorn sheep, woodpeckers, and whales, may provide preventive applications in humans. The advantages of an in‐depth study of these unconventional animals are threefold. First, to increase knowledge of the often‐understudied species in question; second, to improve common animal models based on the study of their extreme counterparts; and finally, to tap into a source of biological inspiration for comparative studies and translational applications in humans.
What if my coworker builds a better LMX? The roles of envy and coworker pride for the relationships of LMX social comparison with learning and undermining
Authors: Pan Jingzhou , Zheng Xiaotong (Janey) , Xu Haoying (Howie) , Li Jie (Kassie) , Lam Catherine K. 
Published: July 2021

SummaryAlthough the extant literature has demonstrated the benefits of building a higher leader–member exchange (LMX) relationship with a leader, it has overlooked the efforts by lower LMX employees to leverage the difference from higher LMX coworkers. Integrating social comparison theory and EASI theory, we contend that lower LMX social comparison (LMXSC) is associated with positive (self‐improving) and negative (undermining) behavior via different emotional mechanisms and that the focal employee's perceptions of the comparison coworker's pride play a critical role in qualifying the effects of lower LMXSC. The results from a time‐lagged field study and an online experiment reveal that lower LMXSC is associated with both benign and malicious envy, which in turn respectively relate to the focal employee learning and socially undermining the superior coworker. The negative indirect effect of LMXSC on learning behaviors via benign envy is stronger when the coworker compared is perceived to be higher (vs. lower) in authentic pride, whereas the indirect effect of LMXSC on social undermining via malicious envy is stronger when the coworker compared is perceived to be higher (vs. lower) in hubristic pride. We conclude with theoretical and practical implications.
Evolution of future precipitation extremes: Viewpoint of climate change classification
Authors: Sun Shao , Shi Peijun , Zhang Qiang , Wang Jing'ai , Wu Jianguo , Chen Deliang 
Published: July 2021

AbstractClimate change is often described as the average changes in temperature and precipitation; however, it is the change in climate extremes determines the levels of socioeconomic impacts related to climate change. It is generally believed that global warming drives increase in frequency, intensity and duration of precipitation extremes, but these changes vary regionally. Focusing on the relationships between evolution of extreme events and long‐term climate change, here we propose a novel classification scheme based on Kӧppen's system and changes in mean and variability of precipitation, divide the global climate into 20 different changing types and reveal the regional evolution of precipitation extremes. We find that precipitation extremes ascend significantly in wetting regions, especially in tropical and temperate zones, independent with changed variability. As for drying regions, the evolution of extremes is related to precipitation variability. An increase of extremes can still be detected in fluctuant‐drying areas, while a slight decrease can be seen in stabilized‐drying areas. It is surprising to find increase in both wetness and dryness extremes which implies higher intensity of meteorological hazards in densely populated areas. Based on the current and projected growth of population exposure to precipitation extremes, we identify some hotspots with high potential risk in the future.
Exploring the performance implications of precarious work
Authors: Wiengarten Frank , Pagell Mark , Durach Christian F. , Humphreys Paul 
Published: July 2021

AbstractPrecarious work, or employment that is associated with temporary contracts, low earnings and limited or no employee representation, is on the rise. From an operations perspective, these practices should enable flexibility and reduce costs. However, from the perspective of most other social sciences, precarious work harms workers and should harm firm performance. The objective of this research is to provide a comprehensive analysis of the performance implications of precarious work. We collected survey data in the UK from multiple respondents (operations and human resource managers) along with secondary data to explore how the use of precarious work affects a company's financial, operational and occupational health & safety performance. The results were mixed. Precarious work did not have a significant influence on occupational health & safety performance and had a negative relationship with cost performance. We also established an inverted u‐shaped relationship between precarious work and flexibility and financial performance; low levels of precarious work improve flexibility and financial performance and high levels of precarious work harm both. Finally, we explored if high‐performance work practices could moderate these relationships, but the results were mostly insignificant. The results suggest that firms only benefit from relatively low levels of adoption of precarious work.
Quaternary environmental changes in tropical Lake Towuti, Indonesia, inferred from end‐member modelling of X‐ray fluorescence core‐scanning data
Authors: Morlock Marina A. , Vogel Hendrik , Russell James M. , Anselmetti Flavio S. , Bijaksana Satria 
Published: July 2021

ABSTRACTContinental and marine sediments are composed of a mixture from different sources and are influenced by a variety of environmental factors and transport processes prior to deposition. For analysis and interpretation, these sources and processes are often challenging to disentangle. We show that end‐member modelling of X‐ray fluorescence (XRF) core‐scanning data helps to overcome these challenges by unmixing different environmental signals from high‐resolution sediment geochemical records. We apply this approach to a 100 m long lacustrine succession from Lake Towuti, Indonesia, to separate the regional climate and tectonic history from local ecological and diagenetic processes. The resulting six end‐members (EMs) are interpreted to represent changes in ecological (EM1), climatic (EMs 2–4), tectonic (EM 5) and geomorphic (EM6) processes determining changes in sediment composition. Because end‐member analysis allows for the tracking of transient and overlapping processes, climatic changes can be followed throughout the 100 m‐long succession, suggesting alternating wet and dry periods in Central Sulawesi over long (several 100 000 years) time scales. We show that end‐member analysis on elemental data sets offers a detailed and objective means to disentangle depositional processes in sedimentary successions resulting from varying tectonic and environmental factors involved in sediment formation and deposition.
Comparison of outcomes of the Epley and Semont maneuvers in posterior canal BPPV: A randomized controlled trial
Authors: Sinsamutpadung Chayada , Kulthaveesup Anan 
Published: July 2021

AbstractObjectivesThis study aims to compare the efficacy of the Epley and Semont maneuvers in relieving posterior canal benign paroxysmal positional vertigo (BPPV) arising in the in patients at the Outpatient Department of the Department of Otolaryngology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand.MethodIn this prospective, randomized, comparative study, patients were assigned to receive one of the two treatment methods. First, BPPV was diagnosed with the Dix‐Hallpike test. Then, each patient was treated by either the Epley or Semont maneuver. Immediately afterward, the efficacy of treatments was evaluated with the Dix‐Hallpike test, and dizziness intensity was assessed with the visual analog scale (VAS).ResultsThis study enrolled 80 patients with posterior canal BPPV, 40 of which underwent the Epley maneuver and the other 40 underwent the Semont maneuver. In the first week, The Epley maneuver cured 37 (92.5%) of the 40 patients, and the Semont maneuver cured 36 (90%) of the 40 patients. Statistical analysis revealed no significant difference in the efficacy of these treatments (P = .251). Regarding dizziness intensity, VAS scores decreased from 6.48 to 1.65 after the Epley maneuver and from 6.53 to 2.18 after the Semont maneuver. Statistical analysis revealed that the Epley maneuver was superior to the Semont maneuver (P = .009) in reducing dizziness intensity.ConclusionsThe Epley and Semont maneuvers had similar efficacy in curing posterior canal BPPV. Regarding the severity of dizziness after treatment, the Epley maneuver produced significantly better results than did the Semont maneuver.Level of Evidence: II
Motor unit number index: A potential electrophysiological biomarker for pediatric spinal muscular atrophy
Authors: Boulay Christophe , Delmont Emilien , Audic Frédérique , Chabrol Brigitte , Attarian Shahram 
Published: July 2021

AbstractIntroduction/AimsIn adult spinal muscular atrophy (SMA), the motor unit number index (MUNIX) has been shown to be an useful electrophysiological biomarker. This study evaluated the feasibility and the clinical relevance of using the MUNIX technique for patients with pediatric SMA (Ped‐SMA) and correlated MUNIX results with clinical scores.MethodsFourteen patients with type II Ped‐SMA (11 females; median age 11 y [interquartile range (IQR), 4.8–17 y]) and 14 controls (nine females; median age 10.75 y [IQR, 6.5–13.4 y]) were enrolled and matched by sex, age, height, weight, and body mass index. Clinical examination included manual muscle testing, dynamometry (grasp and pinch), and motor function measure (MFM). The MUNIX technique was evaluated in the abductor digiti minimi (ADM) and abductor pollicis brevis (APB) on two sides when possible.ResultsIn the patients with Ped‐SMA, the MUNIX and compound muscle action potential (CMAP) amplitudes were significantly decreased and the motor size unit index (MUSIX) was significantly increased in the ADM and APB when compared to controls. The intraclass correlation coefficient was good for the intrarater variability of the CMAP amplitude, MUNIX, and MUSIX in the ADM (0.95, 0.83, and 0.89, respectively) and the APB (0.98, 0.96, and 0.94, respectively). The total CMAP amplitude correlated with the grasp and pinch scores (P < .05), and the MUNIX measurements correlated with the MFM scores.DiscussionThe MUNIX technique, which accurately estimated lower motor neuron loss and the number of remaining functional motor units, was shown to be a useful electrophysiological biomarker for disease progression and a potential biomarker for treatment response.
Core competency scale for operating room nurses in China: Scale development, reliability and validity evaluation
Authors: Mei Na , Chang Ling , Zhu Zhonghai , Dong Min , Zhang Min , Zeng Lingxia 
Published: July 2021

AbstractAimsTo develop a competency scale for operating room nurses and test its reliability and validity.BackgroundThe existing Chinese Registered Nurse Competency Scale and the core competency scale for operating room nurses developed abroad cannot fully meet the capacity needs of Chinese operating room nurses.MethodsThe scale was developed based on the results of qualitative interview and the Delphi method. Ten experts were selected for expert consultation, and 300 operating room nurses were recruited by convenience sampling for a cross‐sectional survey to test the reliability and validity of instrument.The reliability and validity of the scale was assessed based on internal consistency reliability, test–retest reliability and confirmatory factor analysis. Data collection was conducted between March to July, 2015.ResultsAn initial scale with 42 items was confirmed, and 36 items remained. The internal consistency Cronbach's α was 0.97 for the overall scale and 0.88–0.94 for the subscales. The retest reliability ranged from 0.55–0.96. Five factors were extracted by exploratory factor analysis, and they explained 66% of the total variance. The fitting indices of the confirmatory factor analysis were as follows: χ2/df = 3.47, CFI = 0.83, TLI = 0.81, SRMR = 0.06 and RMSEA = 0.09.ConclusionsThe core competency scale for operating room nurses with 5 components and 36 items had acceptable reliability and validity. The scale could continue to be optimized in the future.
Monitoring by acoustic emission the mechanical behavior of polystyrene submitted to stress cracking at different temperatures
Authors: Trindade Luciane C. , Rabello Marcelo S. 
Published: July 2021

AbstractEnvironmental stress cracking (ESC) is one of the main phenomena that limit the use of polymers, being responsible for an expressive number of premature failures in service. This occurs when mechanical loading is combined with a certain kind of chemical agent, causing surface cracks and, eventually, catastrophic failure. This issue is not widely reported in the literature, and the usual procedures for investigation involve conventional mechanical testing. Alternative tools, such as, the technique of acoustic emission (AE) to monitor the stages of fracture, are rarely used. In this work, injection molded polystyrene were submitted to stress cracking conditions, using two types of active fluids and different exposure temperatures (25, 40, and 55°C). The AE technique was applied simultaneously with the mechanical testing to monitor parameters like intensity of the hits and energy released during the deformation and fracture. The results showed that the failure by ESC was related to the fluid interaction with the polymer and was very dependent on the exposure temperature. The use of acoustic emission technique was very useful to differentiate the effects of the various exposure conditions and to explain certain fracture characteristics observed by visual inspection and by scanning electron microscopy.
Interfacial lubricating effect in phase coarsening of polyethylene/polycaprolactone/polyethylene oxide tri‐continuous polymer blends
Authors: Haji Abdolrasouli Mehdi , Jalali Dil Ebrahim , Khorshidi Mal Ahmadi Jamshid 
Published: July 2021

AbstractThis work aims at studying the mechanism involved in the phase coarsening of ternary tri‐continuous polymer blends. To this aim, the phase coarsening behaviors of a co‐continuous polyethylene (PE)/polyethylene oxide (PEO) blend, and a tri‐continuous PE/polycaprolactone (PCL)/PEO blend during the quiescent annealing process are studied. Rheological characterization showed that the zero‐shear viscosities of PE and PCL phases were similar but much less than the zero‐shear viscosity of the PEO phase. The evolution of the microstructure of the blends during annealing was characterized using a characteristic length scale (λ). It was found that λ in both co‐ and tri‐continuous blends increased linearly in the early stages of annealing but the phase coarsening rate decreased in both systems at longer annealing times. In general, the tri‐continuous blend showed much faster phase coarsening rate. The effects of kinetic and thermodynamic parameters on the observed phase coarsening behaviors are discussed in detail. A new lubricating mechanism is proposed in which the deformation of the PCL layer between PE and PEO phases reduces the effect of high viscosity of the PEO phase and increases the phase coarsening rate in ternary blends. The obtained results provide a new insight into the role of the middle layer in tri‐continuous polymer blends on controlling the phase morphology of these systems.
Network sensitivity function, optimization and robust performance in dynamic average consensus
Authors: Zhang Shiqi , Li Zhongkui , Li Bing , Liu Zhengmin 
Published: July 2021

AbstractIn this article, a novel sensitivity minimization approach is proposed to optimize the performance of proportional‐integral (PI) dynamic average consensus (DAC) algorithms subject to measurement noises and model uncertainties. Network sensitivity and complementary sensitivity functions are defined to characterize the effects of the reference signals and measurement noises on the tracking error, respectively. Minimization of the norms of network sensitivity and complementary sensitivity functions, describing how large the PI DAC algorithm amplifies the reference and noise signals in the worst case, are conducted to optimize the tracking performance with respect to the reference signals and measurement noises without requiring prior knowledge. Further, by studying the weighted optimization of the network sensitivity functions, necessary and sufficient conditions are provided for the PI DAC algorithm to have a good tracking performance for low‐frequency reference signals and high‐frequency measurement noises. The proposed sensitivity minimization approach is shown to be a robust approach, by considering the PI DAC algorithm in the presence of norm‐bounded additive uncertainties. The robust weighted performance specification is formulated and a sufficient condition is provided, relying on the network topology, the bound of the uncertainties, and the parameters of the DAC algorithms. A tradeoff relationship between the tracking performance and robustness is unveiled. The special case of proportional DAC algorithms is similarly discussed.
Managing global value chain triversity and innovation performance using social mechanisms
Authors: Bahl Mona , Lahiri Somnath 
Published: July 2021

AbstractScholarly interest in global value chain (GVC) has gained momentum in recent years, yet a comprehensive framework that elucidates how GVC affects an important firm‐level outcome—innovation performance (IP)—is so far elusive. To address this gap, we develop a conceptual framework related to three diversities (activity, governance structure, and partner location) that lead firms in GVC utilize in order to enhance IP. We draw upon the GVC and social capital research to develop the framework. We propose that the three diversities (collectively termed as triversity) have the potential to affect lead firms' IP positively as well as negatively. We further propose that mechanisms related to the three dimensions of social capital (relational, cognitive, and structural) help augment the positive effects and mitigate the negative effects of triversity on IP. This article contributes to the understanding of the relationship between GVC triversity, IP, and social mechanism.
Optimising top-quark threshold scan at CLIC using genetic algorithm
Authors: Nowak K. , Żarnecki A.F. 
Published: July 2021

AbstractOne of the important goals at the futuree+e−colliders is to measure the top-quark mass and width in a scan of the pair production threshold. However, the shape of the pair-production cross section at the threshold depends also on other model parameters, as the top Yukawa coupling, and the measurement is a subject to many systematic uncertainties. Presented in this work is the study of the top-quark mass determination from the threshold scan at CLIC. The most general approach is used with all relevant model parameters and selected systematic uncertainties included in the fit procedure. Expected constraints from other measurements are also taken into account. It is demonstrated that the top-quark mass can be extracted with precision of the order of 30 to 40 MeV, including considered systematic uncertainties, already for 100 fb−1of data collected at the threshold. Additional improvement is possible, if the running scenario is optimised. With the optimisation procedure based on the genetic algorithm the statistical uncertainty of the mass measurement can be reduced by about 20%. Influence of the collider luminosity spectra on the expected precision of the measurement is also studied.