bluuebunny/crossref_metadata_2025 huggingface dataset:
Global adaptive neural backstepping control of a flexible hypersonic vehicle with disturbance estimation
Authors: Zhao He-Wei , Yang Li-bin
Published: October 2021

Purpose

This paper aims to discuss the precise altitude and velocity tracking control of a hypersonic vehicle, a global adaptive neural backstepping controller was studied based on a disturbance observer (DOB).

Design/methodology/approach

The DOB combined with a radial basis function (RBF) neural network (NN) was used to estimate the disturbance terms that are generated by the flexible modes of the hypersonic vehicle system. A global adaptive neural method was introduced to approximate the unknown system dynamics, with robust control terms pulling the system transient states back into the neural approximation domain externally.

Findings

The globally uniformly ultimately bounded for all signals of a closed-loop system can be guaranteed by the proposed control algorithm. Additionally, the command filtered backstepping methods can avoid the explosion of the complexity problem caused by the backstepping design process. In addition, the effectiveness of the proposed controller can be verified by the simulation used in this study.

Research limitations/implications

Normally lateral dynamics issue should be discussed in the process of control system designed, the lateral dynamics are not included in the nonlinear dynamic model of hypersonic vehicle used in this paper, merely the longitudinal flight dynamics are discussed in this paper.

Originality/value

The flexible states in rigid modes are considered as the disturbance of the system, which is estimated by structuring DOB with NN approximations. The compensating tracking error and prediction error are used in the update law of RBF NN weight. The differential explosions complexity derived from the backstepping procedure is dealt with by using command filters.
Persons with disability perception of facilities management service quality: hospital buildings in Malaysia
Authors: Awang Nuratiqah Aisyah , Chua Shirley Jin Lin , Ali Azlan Shah , Au-Yong Cheong Peng , Naicker Amaramalar Selvi , Yuliawiratman Brenda Saria
Published: October 2021

Purpose

This study aims to discover the perception of persons with disabilities (PWDs) towards facilities management (FM) service quality at hospital buildings in Malaysia.

Design/methodology/approach

A questionnaire survey was conducted with 99 respondents in selected hospitals in Selangor, Malaysia.

Findings

This study aims to discover the perception of PWDs towards FM service quality, and it has found a gap for improvement. The area that requires the highest attention includes the importance of (1) assurance on accessibility despite maintenance activity being conducted (2) criticality of facilities maintenance itself, (3) assurance on comfort and safety, (4) reliable medium to ask for assistance or giving feedback, (5) signage that is clearly seen and easily understood and (6) staff responsiveness.

Research limitations/implications

This instrument is validated by PWDs under the physical disability category only, specifically in the hospital context. Future research is recommended to identify the FM service quality aspect for different categories of disability (sensory, mental or intellectual impairment).

Practical implications

The findings provide evidence for FM to consider PWDs' perceptions in FM strategy development. Even FM provides a healthcare support system. FM service quality partly reflects healthcare service quality.

Social implications

Accommodating the need of PWDs through the improvement of FM service quality aspect will partly fulfil the right of PWDs for equality of access to healthcare.

Originality/value

This SERVQUAL tools can be improvised and used to measure the perception of PWDs on FM service quality systematically and holistically. Understanding the service quality aspect is important for a facility manager to precisely measure and prioritise what is truly important to the building users with special needs and try to accommodate this need in the management activity.
The short-term mean reversion of stock price and the change in trading volume
Authors: Jung Woosung , Kang Mhin
Published: October 2021

This study aims to analyze the effect of change in trading volume on the short-term mean reversion of the stock price in the Korean stock market. Through the variance ratio test, this paper finds that the market shows the mean reversion pattern after 2000, but not before. This study also confirms that the mean reversion property is significantly reduced if the effect of change in trading volume is excluded from the return of a stock with a significant contemporaneous correlation between return and change in trading volume in the post-2000 market. The results appear in both the Korea Composite Stock Price Index and Korea Securities Dealers Automated Quotation. This phenomenon stems from the significance of the return response to change in trading volume per se and not the sign of the response. Additionally, the findings imply that the trading volume has a term structure because of the mean reversion of the trading volume and the return also has a partial term structure because of the contemporaneous correlation between return and change in trading volume. This conclusion suggests that considering the short-term impact of change in trading volume enables a more efficient observation of the market and avoidance of asset misallocation.
Figures in the carpet of branding
Authors: Brown Stephen
Published: October 2021

Purpose

Many have noted the role of metaphor in branding understanding. More than mere decorative frills, tropes play a fundamental, foundational part in the process. The purpose of this comment is to consider some of the branding's core conceits and classifies them for scholarly convenience.

Design/methodology/approach

Metaphors, first and foremost, are figures of speech not analytical tools or techniques. Accordingly, the commentary adopts an appropriate literary approach to its subject matter. Reflective for the most part, it seeks to deconstruct and reconstruct simultaneously. Suggestion not stipulation is the aim.

Findings

After scrutinising branding's figurative landscape, then focussing on several promising analogies, the commentary concludes with a cautionary note concerning internal branding. Metaphor is not all fun and games, nor the be all and end all of branding understanding.

Originality/value

Services marketing possesses two powerful and deeply entrenched tropes – relationships and dramaturgy. Although this comment touches on both, particularly the former, it points out the plethora of figurative possibilities, some fresh, others familiar, that are available to brand managers and researchers both.
Climate change and web archives: an Ibero-American study based on the Portuguese and Brazilian contexts
Authors: Rockembach Moisés , Serrano Anabela
Published: October 2021

Purpose

The purpose of this investigation is to analyze information on the web and its preservation as the digital heritage of events related to climate change and the environment in Portugal and Brazil, thus contributing to web preservation in the Ibero-American context.

Design/methodology/approach

A theoretical and applied investigation using mixed methods to collect and analyze qualitative and quantitative data from three sources: the Internet Archive and the public collection of Archive-It, the Portuguese web archive, and a selection from collections compiled by a research group (UFRGS) on web archiving and digital archiving in Brazil.

Findings

Web archive initiatives started in 1996; however, over the years collections have narrowed from nationally relevant themes to specialized thematic niches. The theme “climate change” has had an increasing impact on scientific and mainstream discussion in the 2000s, and by 2010 the over-arching theme became focused on digital preservation of web content, as demonstrated in this study. Failure to preserve data can lead to a rapid loss of climate change information, due to the inherent ephemerality of the web.

Originality/value

The paper demonstrates the relevance of preserving web content on climate change by showing what has been preserved to date and what will need to be preserved in the future.
Blockchain adoption in supply networks: a social capital perspective
Authors: Galati Francesco
Published: October 2021

Purpose

This study aims to contribute to the early but fervent debate on blockchain and supply networks by proposing a novel theoretical perspective on blockchain adoption grounded on social capital theory. In particular, it seeks to answer the following question: what is the role of social capital in shaping the decision to adopt blockchain in supply networks?

Design/methodology/approach

Multiple case-studies, based on interviews performed with managers of eight firms, were used.

Findings

The social capital theory emerged as an additional but necessary lens to investigate blockchain implementation in supply networks. The intuitions proposed highlighted the importance of managers’ sensemaking for investigating technology adoption. Relational capital emerged as a necessary but not sufficient condition to adopt blockchain in supply networks. In addition, it is argued a relationship between competitive opportunities at the firm level and the idea to adopt the blockchain. The opportunity to act as “Tertius Gaudens” or as “Tertius Iungens” information brokers in supply networks should severely affect firms’ proneness toward the adoption of blockchain solutions.

Originality/value

This is one of the first studies in the literature investigating blockchain adoption in supply networks from a social capital perspective. It introduces new issues to the debate related to the role of blockchain in the supply chain by discussing the role of goal misalignment and competitive advantage, which emerged as crucial for shaping the decision to adopt blockchain in supply networks.
The transcriptomic signature of cold and heat stress in benthic foraminifera—Implications for range expansions of marine calcifiers
Authors: Titelboim Danna , Thangarjan Starlin , Raposo Débora , Morard Raphaël , Kucera Michal , Ashckenazi‐Polivoda Sarit , Almogi‐Labin Ahuva , Herut Barak , Manda Sneha , Abramovich Sigal , Gold David A. , Abdu Uri
Published: October 2021

Global warming permits range expansions of tropical marine species into mid‐latitude habitats, where they are, however, faced with cold winter temperatures. Therefore, tolerance to cold temperatures may be the key adaptation controlling zonal range expansion in tropical marine species.

Here we investigated the molecular and physiological response to cold and heat stress in a tropical symbiont‐bearing foraminifera that has successfully invaded the Eastern Mediterranean.

Our physiological measurements indicate thermal tolerance of the diatom symbionts but a decrease in growth for the foraminifera host under both cold and warm stress.

The combined (‘holobiont’) transcriptome revealed an asymmetric response in short‐term gene expression under cold versus warm stress. Cold stress induced major reorganization of metabolic processes, including regulation of genes involved in photosynthesis. Analyses limited to genes that are inferred to belong to the symbionts confirm that the observed pattern is due to changes in the regulation of photosynthesis‐related genes and not due to changes in the abundance of the symbionts.

In contrast to cold stress, far fewer genes change expression under heat stress and those that do are primarily related to movement and cytoskeleton. This implies that under cold stress, cellular resources are allocated to the maintenance of photosynthesis, and the key to zonal range shifts of tropical species could be the cold tolerance of the symbiosis.

A free Plain Language Summary can be found within the Supporting Information of this article
Cryptic eco‐evolutionary feedback in the city: Urban evolution of prey dampens the effect of urban evolution of the predator
Authors: Brans Kristien I. , Tüzün Nedim , Sentis Arnaud , De Meester Luc , Stoks Robby
Published: October 2021

Most research on eco‐evolutionary feedbacks focuses on ecological consequences of evolution in a single species. This ignores the fact that evolution in response to a shared environmental factor in multiple species involved in interactions could alter the net cumulative effect of evolution on ecology.

We empirically tested whether urbanization‐driven evolution in a predator (nymphs of the damselfly Ischnura elegans) and its prey (the water flea Daphnia magna) jointly shape the outcome of predation under simulated heatwaves. Both interactors show genetic trait adaptation to urbanization, particularly to higher temperatures.

We cross‐exposed common‐garden reared damselflies and Daphnia from replicated urban and rural populations, and quantified predation rates and functional response traits.

Urban damselfly nymphs showed higher encounter and predation rates than rural damselflies when exposed to rural prey, but this difference disappeared when they preyed on urban Daphnia. This represents a case of a cryptic evo‐to‐eco feedback, where the evolution of one species dampens the effects of the evolution of another species on their interaction strength. The effects of evolution of each single species were strong: the scenario in which only the predator or prey was adapted to urbanization resulted in a c. 250% increase in encounter rate and a c. 25% increase in predation rate, compared to the rural predator–rural prey combination.

Our results provide unique evidence for eco‐evolutionary feedbacks in cities, and underscore the importance of a multi‐species approach in eco‐evolutionary dynamics research.
Ectopic cervical thymi and no thymic involution until midlife in naked mole rats
Authors: Emmrich Stephan , Tolibzoda Zakusilo Frances , Trapp Alexandre , Zhou Xuming , Zhang Quanwei , Irving Ellen M. , Drage Michael G. , Zhang Zhengdong , Gladyshev Vadim N. , Seluanov Andrei , Gorbunova Vera
Published: October 2021

Immunosenescence is a hallmark of aging and manifests as increased susceptibility to infection, autoimmunity, and cancer in the elderly. One component of immunosenescence is thymic involution, age‐associated shrinkage of the thymus, observed in all vertebrates studied to date. The naked mole rat (Heterocephalus glaber) has become an attractive animal model in aging research due to its extreme longevity and resistance to disease. Here, we show that naked mole rats display no thymic involution up to 11 years of age. Furthermore, we found large ectopic cervical thymi in addition to the canonical thoracic thymus, both being identical in their cell composition. The developmental landscape in naked mole rat thymi revealed overt differences from the murine T‐cell compartment, most notably a decrease of CD4+/CD8+ double‐positive cells and lower abundance of cytotoxic effector T cells. Our observations suggest that naked mole rats display a delayed immunosenescence. Therapeutic interventions aimed at reversing thymic aging remain limited, underscoring the importance of understanding the cellular and molecular mechanisms behind a sustained immune function in the naked mole rat.
Responding to the China Challenge in Techno‐nationalism: Divergence between Germany and the United States
Authors: Starrs Sean Kenji , Germann Julian
Published: October 2021

President Xi Jinping has made clear that the ‘Great Rejuvenation of the Chinese Nation’ will involve world‐leading competitiveness: his ‘Made in China 2025’ plan identifies 10 core sectors of advanced technology. This article investigates how elites in the United States and Germany have responded to this ‘China challenge’, a burgeoning ‘techno‐nationalist’ phase of globalization. First, the article explores the divergent state responses of the USA and Germany: while both national elites are concerned, the reaction of the US has been far more confrontational. It then tries to explain this striking contrast in terms of the disparate domestic constituents. The US since Trump has aligned electoral grievances around manufacturing job losses with the interests of the national security establishment. In contrast, German labour has fared better in globalization, and the German state has not been able to override the interests of German capital in the way that the US has. Thus, the authors offer an account of how Germany and the US have responded differently to the China challenge, as well as explaining why with reference to the divergent structural conditions and class interests. The article ends by speculating that ‘techno‐nationalism’ will only accelerate in the face of the COVID‐19 pandemic.
The behavioral agency model: Revised concepts and implications for operations and supply chain research
Authors: Gomez‐Mejia Luis R. , Martin Geoff , Villena Veronica H. , Wiseman Robert M.
Published: October 2021

The COVID 19 crisis and geopolitical ruptures of recent years have highlighted the importance of operations and supply chain management (OSCM) to firms and society. How do OSCM executives make decisions under uncertainty, and how do they balance the competing needs of various stakeholders? The behavioral agency model (BAM), which has been widely used in the management literature, focuses on the executive as the unit of analysis, like the behavioral science research in which it is embedded; by contrast, much of the supply chain risk management research has examined risk at the level of the firm. We review BAM literature and its core constructs, refine its original predictions, identify OSCM executive decision contexts that could take advantage of BAM, and highlight research opportunities using BAM. We aim to provide a platform for further risk research applying BAM in the domain of OSCM executive decision‐making.
Do pledges lead to more volunteering? An experimental study
Authors: Capra C. Mónica , Jiang Bing , Su Yuxin
Published: October 2021

The effect of pledges on donations is ambiguous. Pledges can boost donations because pledges make it easier for people to accept a request without incurring the costs of donating right away. However, pledges can also decrease donations because individuals who pledge renege on their promises. In this paper, we study the effect of pledges on volunteering using an online experiment. We find that pledges decrease immediate rejection to volunteering requests, but pledges are often reneged later, resulting in no overall change in volunteering rates. We provide a theoretical framework for understanding the conditions under which these results emerge.
Health literacy predicts Covid‐19 awareness and protective behaviours of university students
Authors: Naveed Muhammad Asif , Shaukat Rozeen
Published: October 2021

Background

Health literacy is expected to help individuals deal with the required infection control and knowledge to cope with the COVID‐19 pandemic.

Objectives

This study examined the impact of health literacy on Covid‐19 awareness and protective behaviours of university students in Pakistan.

Methods

An online questionnaire was used to collect data from students at three universities in Punjab. The approved questionnaire contained 12 statements related to HL, 21 items towards Covid‐19 awareness, and 11 statements related to protective behaviours, along with some demographic data. Data analysis used Pearson correlation and simple linear regression.

Results

Health literacy of university students positively predicted their Covid‐19 awareness and protective behaviours indicating that students with high health literacy were likely to be more aware of Covid‐19 and adopt health protective behaviours. There were gender and rural/urban differences.

Conclusions

The results demonstrated an urgent need for planning a needs‐based health literacy programme focusing specifically on Covid‐19 literacy in Pakistan. This research might help policy‐makers, NGOs, and health librarians devise suitable programme.
Directional bioconversion and optimization of stevioside into rubusoside by Lelliottia sp. LST-1
Authors: Huang Ke , Huang Jingyu , Lin Jing , Li Hongwei , Xin Jiaqi , Ma Ziyang , Sang Junhao , Hong Zhiyun , Zeng Guohong , Hu Xiufang , Li Ou
Published: October 2021

Aims

The present study aimed to specifically transform stevioside (ST) into rubusoside (RS) through bioconversion with high efficiency, seeking to endow steviol glycosides (SGs) with subtle flavours for commercial acceptability.

Methods and Results

An endophytic bacterium named Lelliottia LST-1 was screened and confirmed to specifically convert ST into RS, reaching a conversion rate of 75.4% after response surface optimization. Phylogenetic analysis combined with complete genome sequencing demonstrated that LST-1 was also presumed to be a new species. To further explore the principle and process of biological transformation, the potential beta-glucosidases GH3-1, GH3-2, GH3-3 and GH3-4 were expressed, purified and reacted with SGs. High-performance liquid chromatography revealed that all enzymes hydrolysed ST and generated RS, but substrate specificity analysis indicated that GH3-2 had the highest substrate specificity towards STs and the highest enzyme activity.

Conclusion

The potential β-glucosidase GH3-2 in Lelliottia sp. LST-1 was found to specifically and efficiently convert ST to RS.

Significance and Impact of Study

The efficient biotransformation of ST into RS will be beneficial to its large-scale production and extensive application in the food and pharmaceutical industries.
Growth hormone deficiency in adults with hypopituitarism—What are the risks and can they be eliminated by therapy?
Authors: Johannsson Gudmundur , Ragnarsson Oskar
Published: October 2021

Growth hormone (GH) deficiency develops early in patients with hypothalamic‐pituitary disorders and is therefore common among these patients. GH deficiency in adults is associated with increased morbidity, increased body fat mass, abdominal obesity, dyslipidaemia, reduced exercise capacity, impaired cardiac function as well as reduced self‐reported well‐being and impaired quality of life. Since recombinant human GH became available as replacement therapy more than 25 years ago, randomised controlled trials and long‐term studies, together with meta‐analyses, have shown improved outcomes in adult patients with hypopituitarism receiving GH. Many of the features associated with GH deficiency in adults improve, or even normalize, and the safety profile is reassuring. The increased interest in GH deficiency in adults with hypothalamic‐pituitary disorders has also contributed to the identification of other factors of importance for an outcome such as the replacement of other pituitary hormone deficiencies, and the management of the underlying hypothalamic‐pituitary disease, most commonly a pituitary tumour.

In this narrative review, we summarize the burden of GH deficiency in adults with hypopituitarism, the impact of GH replacement on the outcome, as well as safety. Based on currently available data, GH replacement should be considered routine management of adults with hypopituitarism.
Instrumental characteristics from extensional rheology and tribology of polysaccharide solutions
Authors: Funami Takahiro , Nakauma Makoto
Published: October 2021

Instrumental characteristics from extensional rheology and tribology for aqueous xanthan gum (XG) and locust bean gum (LBG) solutions were studied in the presence or absence of simulated saliva. Extensional viscosity was calculated from the filament shrinkage behavior using a capillary breakup extensional rheometer, whereas the friction coefficient was measured using a set‐up consisting of polydimethylsiloxane substrate and a glass ball bearing on a rotational rheometer. Increase in extensional viscosity was detected immediately after initiation of extensional flow, particularly XG, and also immediately before the filament rupture, particularly LBG. Extensional viscosity tended to decrease with increased addition of simulated saliva for XG, while to increase for LBG. In both cases, effect of cations in the saliva was greater than that of mucin. From the shape of the Stribeck curve (i.e., dependence of the friction coefficient on the entrainment speed) and comparison of the friction coefficient itself, lubricity of XG was greater than that of LBG. Simulated saliva added decreased the friction coefficient for each polysaccharide through functions of cations rather than mucin. Extensional viscosity and tribological measurements revealed mechanical properties of polysaccharide solutions which cannot be determined or quantified by shear viscosity alone.
Peer‐assisted learning in medical education: A systematic review and meta‐analysis
Authors: Brierley Clarissa , Ellis Leila , Reid Emily Roisin
Published: October 2021

Objectives

The prevalence of peer‐assisted learning (PAL) featuring alongside the core medical curriculum is increasing; however, the evidence base for PAL's efficacy on academic performance is limited. This systematic review of randomised studies of PAL in medical school sets out to assess the impact of PAL on academic outcomes in medical school and evaluate whether PAL confers a benefit in specific educational contexts.

Methods

A literature search was conducted across MEDLINE, Ovid Embase, Web of Science and Education Research Complete. Titles and abstracts were screened, and records were selected following strict eligibility criteria. Following full‐text assessment for eligibility, two reviewers independently extracted data from the final selection of records and a meta‐analysis was performed. Studies were classified using a modified version of Kirkpatrick's levels of learning. Student test scores were standardised by calculating the standardised mean difference (SMD).

Results

Twenty‐seven randomised controlled trials were eligible for inclusion, and twenty‐one provided sufficient and complete data to enable meta‐analysis. There was a significant improvement in the academic performance of medical students who received PAL compared with those in the control group (SMD = 0.52 [95% confidence interval 0.18–0.85]; p = .003). The impact of PAL was greater amongst clinical medical students (SMD = 0.63; p = .02) than preclinical medical students (SMD = 0.39; p = .08) and when used for teaching practical skills (SMD = 0.69; p = .001) compared with theory (SMD = −0.11; p = .21). Students taught by PAL also achieved better results in assessments conducted more than four weeks after course completion (SMD = 1.20; p = .04). [Correction added on 8 November 2020 after first publication. The data values in the Results section have been corrected in this version.]

Conclusions

Medical students experiencing PAL benefit in terms of academic performance, relative to those not receiving PAL. PAL is of greatest value in the clinical stages of training and for practical skills. The long‐term outcomes of PAL remain a priority for future research.
Single cell biology—a Keystone Symposia report
Authors: Cable Jennifer , Elowitz Michael B. , Domingos Ana I. , Habib Naomi , Itzkovitz Shalev , Hamidzada Homaira , Balzer Michael S. , Yanai Itai , Liberali Prisca , Whited Jessica , Streets Aaron , Cai Long , Stergachis Andrew B. , Hong Clarice Kit Yee , Keren Leeat , Guilliams Martin , Alon Uri , Shalek Alex K. , Hamel Regan , Pfau Sarah J. , Raj Arjun , Quake Stephen R. , Zhang Nancy R. , Fan Jean , Trapnell Cole , Wang Bo , Greenwald Noah F. , Vento‐Tormo Roser , Santos Silvia D.M. , Spencer Sabrina L. , Garcia Hernan G. , Arekatla Geethika , Gaiti Federico , Arbel‐Goren Rinat , Rulands Steffen , Junker Jan Philipp , Klein Allon M. , Morris Samantha A. , Murray John I. , Galloway Kate E. , Ratz Michael , Romeike Merrit
Published: October 2021

Single cell biology has the potential to elucidate many critical biological processes and diseases, from development and regeneration to cancer. Single cell analyses are uncovering the molecular diversity of cells, revealing a clearer picture of the variation among and between different cell types. New techniques are beginning to unravel how differences in cell state—transcriptional, epigenetic, and other characteristics—can lead to different cell fates among genetically identical cells, which underlies complex processes such as embryonic development, drug resistance, response to injury, and cellular reprogramming. Single cell technologies also pose significant challenges relating to processing and analyzing vast amounts of data collected. To realize the potential of single cell technologies, new computational approaches are needed. On March 17–19, 2021, experts in single cell biology met virtually for the Keystone eSymposium “Single Cell Biology” to discuss advances both in single cell applications and technologies.
Ehrlichia‐induced hemophagocytic lymphohistiocytosis in a pediatric kidney transplant recipient
Authors: Singh Nisha S. , Pagano Alexa L. , Hays Allyson J. , Kats Alexander , Dahl Steven M. , Warady Bradley A. , Beins Nathan T. , Yin Dwight E.
Published: October 2021

Background

Kidney transplant patients are susceptible to a variety of infections in the post‐transplant period due to the use of immunosuppressant medications. Ehrlichiosis is a rare infection in solid organ transplant recipients with signs and symptoms that mimic rejection and other viral infections. Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal hyperinflammatory syndrome that can be triggered by infections.

Methods

We describe a pediatric kidney transplant recipient who experienced secondary HLH due to ehrlichiosis within the initial post‐transplant month.

Result

Our patient improved after treatment with doxycycline, corticosteroids, and intravenous immunoglobulin (IVIG).

Conclusion

Clinicians should consider infections such as ehrlichiosis as a potential cause of illness in febrile solid organ transplant recipients in immediate post‐transplant period, especially when accompanied by a compatible exposure history.
SMARCB1(INI1)‐deficient sinonasal adenocarcinoma: Report of a case previously diagnosed as high‐grade non‐intestinal‐type sinonasal adenocarcinoma
Authors: Su Yu‐Ju , Lee Yi‐Hsuan , Hsieh Min‐Shu
Published: October 2021

SMARCB1(INI1)‐deficient sinonasal carcinoma is a recently recognized entity with wide histomorphologic spectrum. The classification of sinonasal adenocarcinoma (SNAC) is complex and yet to be redefined, especially the category of high‐grade non‐intestinal‐type SNAC. Recently SMARCB1(INI1)‐deficient SNACs with an unique oncocytoid/rhabdoid cytomorphology and variable degrees of glandular formation have been reported. Here we described a rare case of SMARCB1(INI1)‐deficient SNAC composed of mainly oncocytoid/rhabdoid cells with mixed solid and cribriform patterns. This case was originally diagnosed as non‐intestinal‐type SNAC and was reclassified due to complete loss expression of SMARCB1(INI1) by immunohistochemistry (IHC). The SMARCB1(INI1) stain provides a valuable tool for identification of this specific type of SNAC. We compared this case with other SNACs diagnosed in our department and reviewed relevant literature for this specific type of SNAC.
Editorial
Authors: Adamec Petr
Published: October 2021

Vážení čtenáři, milé kolegyně a kolegové, přátelé celoživotního vzdělávání a všeho, co s ním souvisí, toto úvodní slovo ke druhému číslu časopisu Lifelong Learning – Celoživotní vzdělávání v roce 2021 píšu v době, kterou označil ministr zdravotnictví České republiky za úpatí další vlny pandemie. Trápí nás již rok a půl a rád bych věřil, že nás už dlouho trápit nebude a že se slova pana ministra nenaplní.

V tomto vydání vám nabízíme dvě studie, jednu teoretickou a jednu empirickou, dvě recenze a jednu zprávu. V první, teoretické studii se Pavel Pecina s Petrem Mariničem z Pedagogické fakulty Masarykovy univerzity zamýšlejí nad aktuálním stavem a vývojem didaktik v odborném vzdělávání v České republice s přesahem na Slovensko. Autorkou druhé, empirické studie je Lucia Pašková z Pefagogické fakulty Univerzity Mateja Bela v Banskej Bystrici, která se zabývá koncepcemi lídrovství zejména v prostředí škol. Ve svém příspěvku se snaží charakterizovat jeden z nejaktuálnějších stylů transformativního lídrovství, který je charakteristický budováním vztahu mezi lídrem a jeho následovníky. Toto budování vztahu může být podle autorky prevencí pracovní osamělosti projevující se na výkonnosti. Jejími respondenty byly téměř dvě stovky učitelů základních škol. Nechte se překvapit výsledky...

Po přečtení těchto studií vám doporučuji recenze dvou odborných publikací. V první recenzi nám kolegyně Silvia Virághová ze Slovenské poľnohospodárské univerzity v Nitře představuje vědeckou monografii Výchova a udržateľný rozvoj, jejímž autory jsou Tímea Šeben Zaťková, Anna Mravcová a Štefan Baranovič, působící tamtéž. Druhou recenzi nám zaslala kolegyně Radmila Burkovičová z Ostravské univerzity a domnívám se, že upozornění na tuto publikaci je velmi vhodné, neboť je svým obsahem nezvykle aktuální. Autoři publikace Univerzitní vzdělávání v minulosti, současnosti a budoucnosti Jaroslav Mužík, Radka Löwenhöfferová a Pavel Krpálek svou monografií zaměřují téměř na všechny aktéry současného vzdělávání – od pedagogů přes studenty a rodiče až po osoby, které se aktuálně zabývají například přípravou akreditačních spisů apod. Autorka recenze hned na prvních řádcích uvádí, že cílem publikace je "reflexe současné situace v univerzitním vzdělávání z globálního, evropského i našeho národního pohledu". Jen řekněte, koho z vás by toto téma nezajímalo?

V závěru prvního čísla letošního ročníku jsem si vás dovolil pozvat na konferenci, kterou vysokoškolský Institut celoživotního vzdělávání pořádá již od roku 2009. Čas oponou trhnul a mně na tomto místě nezbývá než konstatovat, že je po všem a závěr druhého čísla ročníku 2021 věnujeme zprávě ze 13. ročníku mezinárodní vědecké konference ICOLLE, která se konala 8.září 2021 v hotelu Avanti v Brně. Tentokrát byla zaměřena na kompetence pro 21. století a Martina Urbánková v této zprávě shrnuje to nejdůležitější, co se v souvislosti s její úspěšnou organizací událo.

Vážené kolegyně a kolegové, přeji vám pevné zdraví, příjemné chvíle ve společnosti našeho odborného časopisu a úspěšný start do nového akademického roku 2021/2022!

Petr Adamec

předseda redakční rady
Recovering Missing Component Dependence for System Reliability Prediction via Synergy Between Physics and Data
Authors: Li Huiru , Du Xiaoping
Published: October 2021

Predicting system reliability is often a core task in systems design. System reliability depends on component reliability and dependence of components. Component reliability can be predicted with a physics-based approach if the associated physical models are available. If the models do not exist, component reliability may be estimated from data. When both types of components coexist, their dependence is often unknown, and therefore, the component states are assumed independent by the traditional method, which can result in a large error. This study proposes a new system reliability method to recover the missing component dependence, thereby leading to a more accurate estimate of the joint probability density function (PDF) of all the component states. The method works for series systems whose load is shared by its components that may fail due to excessive loading. For components without physical models available, the load data are recorded upon failure, and equivalent physical models are created; the model parameters are estimated by the proposed Bayesian approach. Then models of all component states become available, and the dependence of component states, as well as their joint PDF, can be estimated. Four examples are used to evaluate the proposed method, and the results indicate that the method can produce more accurate predictions of system reliability than the traditional method that assumes independent component states.
Turbulent Flow Around Rectangular Cylinders With Different Streamwise Aspect Ratios
Authors: Kumahor Sedem , Tachie Mark F.
Published: October 2021

Turbulent flows around a square cylinder and a rectangular cylinder with a streamwise aspect ratio (length-to-height) of 5 in a uniform flow were investigated using time-resolved particle image velocimetry (TR-PIV). The Reynolds number based on the cylinder height and oncoming flow velocity was 16,200. Similarities and differences in the flow dynamics over the cylinders and in the near-wake region were examined in terms of the mean flow, drag coefficient, Reynolds stresses, and triple velocity correlations. The budget of turbulent kinetic energy (TKE) as well as temporal and spectral analyses was also performed. The results show that the primary, secondary, and wake vortexes are smaller for the square cylinder compared to the large aspect ratio cylinder. There are regions of elevated Reynolds stresses and triple velocity correlations along the mean separating streamlines, and the magnitudes of these statistics are an order of magnitude higher over the square cylinder compared to the large aspect ratio cylinder. The topology of the triple velocity correlations shows low-speed ejection and high-speed sweep events, respectively, transporting instantaneous Reynolds normal stresses away from the mean separating streamline into the freestream and toward the cylinder surface, regardless of aspect ratio. Near the leading and trailing edges of both cylinders, regions of negative turbulence production are observed, and the dominant components contributing to this occurrence are discussed. Temporal autocorrelation coefficients of the streamwise and vertical velocity fluctuations show a periodic trend, with a periodicity that is directly linked to the Kármán shedding frequency and its second harmonic.
Experimental Study on Rubbing Wear Characteristics of Labyrinth Seal With Trapezoidal Fins
Authors: Yan Xin , Dai Xinbo , He Kun
Published: October 2021

The wear characteristics of the trapezoidal fin against high-speed rotor were experimentally investigated at different final incursion depths, incursion rates, and sliding velocities. To characterize the geometrical effect, a small specimen (SS) and a large specimen (LS) were selected to analyze the mass loss, wear geometry, contact forces, and frictional temperature distributions under different conditions. The results show that the contact-separation is most likely to occur between the trapezoidal fin and rotor. In the rubbing process, the plastic deformation is dominating, and the abrasive and adhesive wears have pronounced effects on the wear behavior of the rubbing interface. The wear performance of the SS is sensitive to the structure imbalance, which induces the combined mushrooming and bending damage in the trapezoidal fin. However, the symmetrical mushrooming damage is generated in the LS. For both SS and LS, the mass loss is decreased with increasing incursion rate and sliding velocity, and the mass loss percentage is pronounced at the early stage of rubbing. The averaged friction coefficient is 0.1–0.16 for the LS whereas 0.1–0.19 for the SS. The peak frictional temperature is 560–640 °C for the LS, while 360–400 °C for the SS. The contact-separation significantly reduces the effects of final incursion depth, incursion rate, and sliding velocity on the wear geometry, contact forces, and temperature rise in the trapezoidal labyrinth fin.
Observation and Discussion of Leading Edge Vortex Shedding From Laboratory-Scaled Cross-Flow Hydrokinetic Turbines in Counter-Rotating Configurations
Authors: Doan Minh , Kai Yuriko , Kawata Takuya , Alayeto Ivan , Obi Shinnosuke
Published: October 2021

In 2011, John Dabiri proposed the use of counter-rotating vertical-axis wind turbines to achieve enhanced power output per unit area of a wind farm. Since then, various studies in the wind energy and marine hydrokinetic (MHK) literature have been dedicated to pairs of vertical axis turbines in both co-rotating and counter-rotating configurations, in terms of their power production, wake characterization, and optimal array design. Previous experimental works suggest an enhancement of up to 27.9% in the system power coefficient of pair configurations compared to a single turbine. Additionally, previous numerical studies have indicated that the increased power output is correlated with higher torque on the turbine blades which correspondingly produces a stronger leading edge vortex. This paper presents an extended investigation into a pair of laboratory scaled cross-flow hydrokinetic turbines in counter-rotating configurations. Experiments were conducted to observe, compare, and discuss the leading edge vortex shedding from the turbine blades during their positive torque phase. The turbines operated in a small water flume at the diameter-based Reynolds number of 22,000 with a 0.316 m/s freestream velocity and 4% turbulent intensity. Using a monoscopic particle image velocimetry setup, multiple realizations of the water flow around each blade at their positive torque phase were recorded and phase-averaged. Results show consistent leading vortex shedding at these turbine angles while a correlation between the turbine power performance and the vortex size and strength was observed.
Wing Flutter Analysis Using Computational Fluid-Structure Interaction Dynamics
Authors: Pohly Jeremy A. , Zhang Mike R. , Zhang Sijun
Published: October 2021

Wing flutter plays a significant role in the performance and life of lifting surfaces such as aircraft wings. It is an instability that causes the wing to no longer be capable of damping out random vibration, and it occurs at the point called the critical speed. Currently, the determination of this critical speed poses a large challenge for aircraft designers, as there is no method that can quickly calculate the conditions that will cause the wing flutter instability. This paper presents wing flutter analyses using computational fluid-structure interaction dynamics. The computed results reveal the potential speed and accuracy of the computational method, which will allow designers to rapidly determine whether their vehicle will be capable of operating safely within its design envelope.
Minimum Wall Distance Computations With Time-Dependent Geometry for CFD
Authors: Wang Liwu , Feng Jian , Liu Yu , Zhang Sijun
Published: October 2021

This paper presents an efficient and scalable method to calculate the minimum wall distance (MWD), which is necessary for the Reynolds-Averaged Navier-Stokes (RANS) turbulence models. The MWD is described by the distance field function which is essentially a partial differential equation (PDE). The PDE is a type of convection-diffusion equation and can be solved by existing computational fluid dynamics (CFD) codes with minor modifications. Parallel computations for the PDE are conducted to study its efficiency and scalability. Encouraging results are obtained and demonstrate the present method is more efficient than all the alternate methods.
How to Improve Accuracy of Existing Ultrasonic Water Meters
Authors: Gryshanova Iryna , Korobko Ivan
Published: October 2021

In present paper, the focus is given to possible ways of increasing accuracy for existing ultrasonic time-of-flight water meters. We will consider transducers with coaxial reflectors working at laminar, transitional and turbulent regimes within their measurement range. Considering error curves of such meters, we can easily resume that they are non-linear and not simply corrected using only one polynomic function. Measurements in laboratory and field conditions demonstrate that there is a shift in the ultrasonic meter’s calibration factor. The deviation of readings starts at Re = 5 000–10 000 and the maximum value is reached at Re = 160. Great inaccuracies referred to the transition from laminar flow to turbulent take place abruptly, which lead to undesirable errors. To understand this phenomenon, the theoretical basis of ultrasonic measurements was analyzed and revealed that typical algorithm for determination of the calibration factor is very questionable since it contains simplified information about velocity profile distribution. Trying to fix this problem, we applied computational fluid dynamics (CFD) modelling of ultrasonic meters with different variants of flow straighteners. Ranges of applicability of a particular turbulence model for a correct description of the velocity profile and other flow parameters in metrological purposes have been evaluated. Due to applied techniques, the flow profile sensitivities of various meter configurations are investigated at different Reynolds numbers comparing to real experiments. To get an improved ultrasonic meter design recirculation zones and flow separation regions inside the flow transducer have been eliminated. As a result, the accuracy of the ultrasonic water meter has increased. Simulations demonstrated reasonable agreement to the error curves obtained on the calibration facility for a whole measurement range.
Effect of Hub Configuration on the Performance of Mixed Flow Turbine for Micro Hydropower in Pipes
Authors: Jang Seungsoo , Song Ji-Hun , Kim Youn-Jea
Published: October 2021

As environmental issues have been on the rise recently, the demand for hydropower is increasing. Micro hydropower in pipes is highly safe, sustainable, and easy to introduce. In this study, a mixed flow turbine is introduced to collect waste energy in pipes, and numerical analysis was conducted to estimate the performance. Efficiency was adopted as an indicator to evaluate the performance, and the performance of three different hub configurations, which are conical, convex, and concave, was investigated. The hydroturbine used in this study was modeled except for the guide vane due to the small scale, and the blade was designed using design of experiments. As a result, three different hub configurations have the best efficiency point between rotational speeds of 3000 rpm and 3200 rpm. The convex hub showed the highest efficiency, which was 1.60% and 3.63% higher than the conical and concave hub, respectively. It is related to the variation in the cross-sectional area of the flow path of the runner depending on the hub configuration. Consequently, the convex hub configuration showed the best performance.
Blade Thickness Redesign to Improve Efficiency and Decrease Unsteady Pressure Pulsation of a Low Specific Speed Centrifugal Pump
Authors: Wu Chengshuo , Wu Peng , Wu Dazhuan
Published: October 2021

The existence of secondary flow in the impeller brings extra energy loss and aggravates the pressure pulsation which will worsen the hydraulic and dynamic performance of the pump. In this paper, based on the forces balance in the direction perpendicular to the streamline, an optimal design method for the blade thickness of a low specific speed centrifugal pump is proposed to suppress the secondary flow in the impeller. The origin impellers with 5 and 7 cylinder blades are redesigned and the hydraulic and dynamic performance of the model pump are investigated by numerical simulation and experimental. Results show that the blade modification proposed in this paper can effectively improve the efficiency of the model pump and reduce the internal pressure pulsations. The internal flow analysis shows that the performance improvement attributes to the suppression of secondary flow in the impeller. And the entropy generation rate is introduced to measure and locate the loss in the pump. Results show that on the one hand, the suppression of secondary flow can reduce the energy loss in the pump and improve the efficiency; on the other hand, it can repress the jet wake structure at impeller outlet and alleviate the intensity of pressure pulsations.