bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic Performance and Characteristics of Anterior Nasal Collection for the SARS-CoV-2 Antigen Test: A Prospective Study in Japan
Authors: Takeuchi Yuto , Akashi Yusaku , Kato Daisuke , Kuwahara Miwa , Muramatsu Shino , Ueda Atsuo , Notake Shigeyuki , Nakamura Koji , Ishikawa Hiroichi , Suzuki Hiromichi
Published: March 2021

We conducted a prospective study in Japan to evaluate the diagnostic performance of the antigen test QuickNavi-COVID19 Ag using anterior nasal samples and to compare the degrees of coughs or sneezes induction and the severity of pain between anterior nasal collection and nasopharyngeal collection. A total of 862 participants were included in the analysis. In comparison to the findings of reverse transcription PCR using nasopharyngeal samples, the antigen test using anterior nasal samples showed 72.5% sensitivity (95% confidence interval [CI]: 58.3%-84.1%) and 100% specificity (95% CI: 99.3%-100%). Anterior nasal collection was associated with a significantly lower degree of coughs or sneezes induction and the severity of pain in comparison to nasopharyngeal collection (p < 0.001). The antigen test using anterior nasal samples showed moderate sensitivity but was less painful and induced fewer coughs or sneezes.
Sharing positive changes made during COVID-19 national lockdown: a multi-method co-production study
Authors: Williams Lynn , MacDonald Bradley , Rollins Lesley , Janssen Xanne , Fleming Leanne , Grealy Madeleine , Kirk Alison , Young David , Flowers Paul
Published: March 2021

Objective

A multi-method co-production study was designed to share psychosocial insights into the adoption of positive changes made during COVID-19 national lockdown in Scotland. We examined: i) the psychosocial patterning of positive changes, ii) the psychosocial processes by which positive change was realised, and worked with partner organizations to share our insights.

Methods

A sequential multi-method design included an online survey (n=2445) assessing positive changes in sleep and physical activity patterns, socio-demographics, mood, social support, coping, and resilience, with multivariate logistic regression analysis. We also employed interviews with a purposive diverse sub-sample of people self-reporting high levels of positive change (n=48) and used thematic analysis. Finally, partnership work translated insights into positive change-sharing targeted resources.

Results

The survey identified positive change was significantly patterned by age, gender and vulnerability to COVID-19. Higher positive reframing and higher active coping were associated with higher levels of cross-domain positive change. Higher symptoms of depression, planning, and self-distraction were associated with less cross-domain positive change. Thematic analysis showed the centrality of perceptions of time, opportunities to self-reflect and engage with the natural world, access support in diverse ways, actively build routine and purposefully build self-efficacy and a sense of control were key to initiating positive change. Our partner organizations focused on the rapid co-production of a series of online resources that shared study insights.

Conclusions

Our study, based around a salutogenic ethos and the constraints of COVID-19, sought to identify and share insights into achieving positive changes at a time of international crisis.
Association Between HIV PrEP Indications and Use in a National Sexual Network Study of Men Who Have Sex with Men
Authors: Weiss Kevin M. , Prasad Pragati , Sanchez Travis , Goodreau Steven M. , Jenness Samuel M.
Published: March 2021

Background

HIV preexposure prophylaxis (PrEP) is effective in preventing HIV transmission. US Public Health Service (USPHS) clinical practice guidelines define biobehavioral indications for initiation. To assess guideline implementation, it is critical to quantify PrEP non-users who are indicated and PrEP users who are not indicated.

Methods

Using data from a national web-based study of men who have sex with men (MSM) between 2017 and 2019, we estimated the association between PrEP use and PrEP indications. Log-binomial regression was used to estimate the relationship between PrEP indications and PrEP use, adjusted for geography and demographics.

Results

Of 3508 sexually active, HIV-negative MSM, 34% met indications for PrEP. The proportion with current PrEP use was 32% among those meeting indications and 11% among those without indications. Nearly 40% of those currently using PrEP did not meet indications for PrEP, and 68% of MSM with indications for PrEP were not currently using PrEP. After adjusting for geography and demographics, MSM with PrEP indications were about 3 times as likely to be currently using PrEP. This association varied slightly by geography and demography.

Conclusions

Indications for PrEP strongly predicted current PrEP use among MSM. However, we identified substantial misalignment between indications and use in both directions (indicated MSM who were not benefitting from PrEP, and MSM taking PrEP while not presently being indicated). This calls for further implementation efforts to improve PrEP delivery to those most in need during periods of elevated sexual risk.
Kinetics of SARS-CoV-2 anti-s IgG after BNT162b2 vaccination
Authors: Grupel Daniel , Gazit Sivan , Schreiber Licita , Nadler Varda , Wolf Tamar , Lazar Rachel , Supino-Rosin Lia , Perez Galit , Peretz Asaf , Tov Amir Ben , Mizrahi-Reuveni Miri , Chodick Gabriel , Patalon Tal
Published: March 2021

Deployment of the BNT162b2 mRNA Covid-19 Vaccine in Israel began in December 2020.

This is a retrospective analysis of serological data, describing SARS-CoV-2 anti-S IgG kinetics in 116 Israeli healthcare workers administrated the BNT162b2 vaccine.

Seroconversion occurred by day 14 in all individuals, with IgG levels peaking approximately 30 days post inoculation.

This study demonstrated the kinetics of the antibody response post vaccination with BNT162b2. The robustness of seroconversion was observed, alongside a statistically significant difference in IgG levels between employees over and younger 50 years of afge. Further research is required in order to examine the antibody kinetics overtime, as well as whether the age-dependent difference persists.
Physiologic flow-conditioning limits vascular dysfunction in engineered human capillaries
Authors: Haase Kristina , Piatti Filippo , Marcano Minerva , Shin Yoojin , Visone Roberta , Redaelli Alberto , Rasponi Marco , Kamm Roger D.
Published: March 2021

Hemodynamics play a central role in the health and disease of the coronary and peripheral vascular systems. Vessel-lining endothelial cells are known mechanosensors, responding to disturbances in flow – with mechanosensitivity hypothesized to change in response to metabolic demands. The health of our smallest microvessels have been lauded as a prognostic marker for cardiovascular health. Yet, despite numerous animal models, studying these small vessels has proved difficult. Microfluidic technologies have allowed a number of 3D vascular models to be developed and used to investigate human vessels. Here, two such systems are employed for examining 1) interstitial flow effects on neo-vessel formation, and 2) the effects of flow-conditioning on vascular remodelling following sustained static culture. Interstitial flow is shown to enhance early vessel formation via significant remodeling of vessels and interconnected tight junctions of the endothelium. In formed vessels, continuous flow maintains a stable vascular diameter and causes significant remodeling, contrasting the continued anti-angiogenic decline of statically cultured vessels. This study is the first to couple complex 3D computational flow distributions and microvessel remodeling from microvessels grown on-chip (exposed to flow or no-flow conditions). Flow-conditioned vessels (WSS < 1Pa for 30 micron vessels) increase endothelial barrier function, result in significant changes in gene expression and reduce reactive oxygen species and anti-angiogenic cytokines. Taken together, these results demonstrate microvessel mechanosensitivity to flow-conditioning, which limits deleterious vessel regressionin vitro, and could have implications for future modeling of reperfusion/no-flow conditions.
Conserving evolutionary history to safeguard our future: incorporating the Tree of Life into biodiversity policy
Authors: Gumbs Rikki , Chaudhary Abhishek , Daru Barnabas H. , Faith Daniel P. , Forest Félix , Gray Claudia L. , Kowalska Aida , Lee Who-Seung , Pellens Roseli , Pipins Sebastian , Pollock Laura J. , Rosindell James , Scherson Rosa A. , Owen Nisha R.
Published: March 2021

Following our failure to fully achieve any of the 20 Aichi biodiversity targets, the future of biodiversity rests in the balance. The Convention on Biological Diversity’s Post-2020 Global Biodiversity Framework (GBF) presents us with the opportunity to preserve Nature’s Contributions to People (NCPs) for current and future generations through conserving biodiversity and averting extinction across the Tree of Life. Here we call attention to our need to conserve the Tree of Life to maintain its benefits into the future as a key mechanism for achieving intergenerational equity. We highlight two indicators available for adoption in the post-2020 GBF to monitor our progress towards safeguarding the Tree of Life. The Phylogenetic Diversity indicator, adopted by IPBES, can be used to monitor biodiversity’s capacity to maintain NCPs for future generations. The EDGE (Evolutionarily Distinct and Globally Endangered) Index monitors how well we are performing at averting the greatest losses across the Tree of Life by conserving the most distinctive species. By committing to safeguarding the Tree of Life post-2020, we can reduce biodiversity loss to preserve nature’s contributions to humanity now and into the future.
A low sugar diet enhancesDrosophilabody size in males and females via sex-specific mechanisms
Authors: Millington Jason W. , Wat Lianna W. , Sun Ziwei , Basner-Collins Paige J. , Brownrigg George P. , Rideout Elizabeth J.
Published: March 2021

InDrosophila, changes to dietary protein elicit different body size responses between the sexes. Whether this sex difference in nutrient-dependent body size regulation extends to other nutrients, such as dietary sugar, remains unclear. Here, we show that reducing dietary sugar enhanced body size inDrosophilamale and female larvae. Indeed, the largest body size was found in larvae reared in a diet without added sugar. Despite the equivalent body size effects of a low sugar diet between males and females, we detected sex-specific changes to the insulin/insulin-like growth factor (IIS) and target of rapamycin (TOR) signaling pathways. Further, we show that the metabolic changes observed in larvae reared on a low sugar diet differ between the sexes. Thus, despite identical phenotypic responses to dietary sugar in males and females, distinct changes to cell signaling pathways and whole-body metabolism were associated with the increased body size in each sex. This highlights the importance of including both sexes in all mechanistic studies on larval growth, as males and females may use different molecular and metabolic mechanisms to achieve similar phenotypic outcomes.
Toxigenic Profile ofClostridium perfringensStrains Isolated from Natural Ingredient Laboratory Animal Diets
Authors: Johnston Michael D. , Whiteside Tanya E. , Williamson Michelle E. , Kurtz David M.
Published: March 2021

Clostridium perfringensis an anaerobic, gram-positive, spore-forming bacterium that ubiquitously inhabits a wide variety of natural environments including the gastrointestinal tract of humans and animals.C. perfringensis an opportunistic enteropathogen capable of producing at least 20 different toxins in various combinations. Strains ofC. perfringensare currently categorized into seven toxinotypes (A, B, C, D, E, F & G) based on the presence/absence of four major toxins (alpha, beta, epsilon & iota) and two minor toxins (enterotoxin & netB). Each toxinotype is associated with specific histotoxic and enteric diseases. The Quality Assurance Laboratory (QAL) at the National Institute of Environmental Health Sciences (NIEHS) screens incoming animal feeds for aerobic, enteric pathogens, such asSalmonellaspp. andE. coli. Recently, QAL has incorporated anaerobic screening of incoming animal feeds. To date, the lab has isolated numerousClostridium species, includingC. perfringens, from 23 lots of natural-ingredient laboratory animal diets.

Importance

Published reports ofClostridium perfringensisolation from laboratory animal feeds could not be found in the literature. Therefore, we performed a toxin profile screening of our isolated strains ofC. perfringensto determine which toxinotypes were present in our laboratory animal diets. As studies progress with immunocompromised strains, gnotobiotic models, and animals with perturbed gut flora, the presence ofC. perfringenscould potentially lead to infection, disease and mortality which would substantiate the need to properly eliminate the bacterium and its spores from diets given to high risk animal populations.
Sector search strategies for odor trail tracking
Authors: Reddy Gautam , Shraiman Boris I. , Vergassola Massimo
Published: March 2021

Terrestrial animals such as ants, mice and dogs often use surface-bound scent trails to establish navigation routes or to find food and mates, yet their tracking strategies are poorly understood. Tracking behavior features zig-zagging paths with animals often staying in close contact with the trail. Upon sustained loss of contact, animals execute a characteristic sequence of sweeping “casts” – wide oscillations with increasing amplitude. Here, we provide a unified description of trail-tracking behavior by introducing an optimization framework where animals search in the angular sector defined by their estimate of the trail’s heading and its uncertainty.In silicoexperiments using reinforcement learning based on this hypothesis recapitulate experimentally observed tracking patterns. We show that search geometry imposes limits on the tracking speed, and quantify its dependence on trail statistics and memory of past contacts. By formulating trail-tracking as a Bellman-type sequential optimization problem, we quantify the basic geometric elements of optimal sector search strategy, effectively explaining why and when casting is necessary. We propose a set of experiments to infer how tracking animals acquire, integrate and respond to past information on the tracked trail. More generally, we define navigational strategies relevant for animals and bio-mimetic robots, and formulate trail-tracking as a novel behavioral paradigm for learning, memory and planning.
Scaling dictates the decoder structure
Authors: Shen Jingxiang , Liu Feng , Tang Chao
Published: March 2021

Despite fluctuations in embryo size within a species, the spatial gene expression pattern and hence the embryonic structure developin proportionwith embryo size, known as the scaling phenomenon. For morphogen induced patterning of gene expression, the positional information encoded in the morphogen profile is decoded by the downstream genetic network (the decoder). In this paper, we show that the requirement of scaling sets severe constraints on the geometric structure of the decoder, which in turn enables deduction of mutants’ behavior and extraction of regulation information without going into any molecular details. We demonstrate that theDrosophilagap gene system achieves scaling in the way consistent with our theory – the decoder geometry required by scaling correctly accounts for the observed gap gene expression pattern in nearly all maternal morphogen mutants. Furthermore, the regulation logic and the coding/decoding strategy of the gap gene system can also be revealed from the decoder geometry. Our work provides a general theoretical framework on a large class of problems where scaling output is induced by non-scaling input, as well as a unified understanding of scaling, mutants’ behavior and gene regulation for theDrosophilagap gene system.
A novel conformational state for SARS-CoV-2 main protease
Authors: Fornasier Emanuele , Macchia Maria Ludovica , Giachin Gabriele , Sosic Alice , Pavan Matteo , Sturlese Mattia , Salata Cristiano , Moro Stefano , Gatto Barbara , Bellanda Massimo , Battistutta Roberto
Published: March 2021

The SARS-CoV-2 main protease (Mpro) has a pivotal role in mediating viral genome replication and transcription of coronavirus, making it a promising target for drugs against Covid-19 pandemic. Here we present a crystal structure of Mprodisclosing new structural features of key regions of the enzyme. We show that the oxyanion loop, involved in substrate recognition and enzymatic activity, can adopt a new conformation, which is stable and significantly different from the known ones. In this new state the S1 subsite of the substrate binding region is completely reshaped and a new cavity near the S2’ subsite is created. This new structural information expands the knowledge of the conformational space available to Mpro, paving the way for the design of novel classes of inhibitors specifically designed to target this unprecedented binding site conformation, thus enlarging the chemical space for urgent antiviral drugs against Covid-19 pandemic.
The parathyroid hormone-dependent activation of osteoblasts enhances hematopoietic stem cell migration and reduces their engraftment abilities
Authors: Even Yasmine , Yi Lin , Chang Chih-Kai , Rossi Fabio M.V.
Published: March 2021

Hematopoietic stem cells (HSCs) in the bone marrow (BM) reside in HSC niches ensuring their maintenance. The HSC niche is made up of perivascular and trabecular cells including osteoblasts whose role on HSCs remains to be clearly defined. Increased numbers of osteoblasts have been observed in the CL2 transgenic mouse expressing a constitutively activated form of the parathyroid hormone (PTH)/PTH-related peptide receptor. This mouse model mimicking PTH anabolic effect has also been described to exhibit increased numbers of the BM stem/progenitor population. Furthermore, PTH is known to induce BM stem/progenitor cell migration into blood circulation. However PTH role on long-term repopulating HSCs (LT-HSCs) is incompletely known. Here we show that CL2 BM contains a regular proportion of LT-HSCs, suggesting that osteoblasts may not be a determinant of LT-HSC numbers but act mainly on more mature progenitors. We further show increased LT-HSC migration in CL2 mice correlated with higher granulocyte colony-stimulating factor (G-CSF) serum levels, supporting the idea that PTH can enhance the migration of LT-HSCs. Finally, we found a defect in the ability of CL2 BM HSCs to reconstitute irradiated BM suggesting that PTH activation of osteoblasts negatively influences abilities of HSC population to engraft and reconstitute irradiated BM. In summary, our study highlights new insights into the role of the PTH-dependent activation of osteoblasts on LT-HSC migration and their BM repopulation abilities. Our findings will be useful to improve treatments on hematological disorders, especially therapies involving HSC harvest and transplantation.
Cellular abundance shapes function in piRNA-guided genome defense
Authors: Genzor Pavol , Konstantinidou Parthena , Stoyko Daniel , Manzourolajdad Amirhossein , Andrews Celine Marlin , Elchert Alexandra R. , Stathopoulos Constantinos , Haase Astrid D.
Published: March 2021

Defense against genome invaders universally relies on RNA-guided immunity. Prokaryotic CRISPR/Cas and eukaryotic RNA interference pathways recognize targets by complementary base-pairing, which places the sequences of their guide RNAs at the center of self/nonself discrimination. Here, we explore the sequence space of PIWI-interacting RNAs (piRNAs), the genome defense of animals, and establish functional priority among individual sequences for the first time. Our results reveal that only the topmost abundant piRNAs are commonly present in every cell, while rare sequences generate cell-to-cell diversity in flies and mice. We identify a skewed distribution of sequence abundance as a hallmark of piRNA populations and show that quantitative differences of more than a thousand-fold are established by conserved mechanisms of biogenesis. Finally, our genomics analyses and direct reporter assays reveal that abundance determines function in piRNA-guided genome defense. Taken together, we identify an effective sequence space and untangle two classes of piRNAs that differ in complexity and function. The first class represents the topmost abundant sequences and drives silencing of genomic parasites. The second class sparsely covers an enormous sequence space. These rare piRNAs cannot function in every cell, every individual or every generation but create diversity with potential for adaptation in the ongoing arms race with genome invaders.
Killing of Gram-negative and Gram-positive bacteria by a bifunctional cell wall-targeting T6SS effector
Authors: Le Nguyen-Hung , Pinedo Victor , Lopez Juvenal , Cava Felipe , Feldman Mario
Published: March 2021

The type VI secretion system (T6SS) is a powerful tool deployed by Gram-negative bacteria to antagonize neighboring organisms. Here, we report thatAcinetobacter baumanniiATCC 17978 (Ab17978) secretes D-lysine (D-Lys), increasing the extracellular pH and enhancing the peptidoglycanase activity of the T6SS effector Tse4. This synergistic effect of D-Lys on Tse4 activity enables Ab17978 to outcompete Gram-negative bacterial competitors, demonstrating that bacteria can modify their microenvironment to increase their fitness during bacterial warfare. Remarkably, this lethal combination also results in T6SS-mediated killing of Gram-positive bacteria. Further characterization revealed that Tse4 is a bifunctional enzyme consisting of both lytic transglycosylase and endopeptidase activities, thus representing a novel family of modularly organized T6SS PG degrading effectors with an unprecedented impact in antagonistic bacterial interactions.

One sentence summary

By modulating local environmental pH through D-Lys secretion,Acinetobacter baumanniienhances the activity of a bifunctional cell wall-targeting T6SS effector, increasing its killing activity against Gram-negative and -positive competitors.
Mutation Profiles, Glycosylation Site Distribution and Codon Usage Bias of HPV16
Authors: Liu Wei , Li Junhua , Du Hongli , Ou Zhihua
Published: March 2021

Human papillomavirus type 16 (HPV16) is the most prevalent HPV type causing cervical cancers. Herein, using 1,597 full genomes of HPV16, we systemically investigated the mutation profiles, surface protein glycosylation sites and the codon usage bias of the eight open reading frames (ORFs) of HPV16 genomes from different lineages and sublineages. Multiple lineage- or sublineage-specific mutation sites were identified. Glycosylation analysis showed that HPV16 lineage D contained the highest number of unique potential glycosylation site in both L1 and L2 capsid protein, which might lead to their antigenic distances from other HPV16 lineages. Nucleotide composition of HPV16 showed that the overall AT content was higher than GC content at the 3rdcodon position. Relatively high ENC values suggested that the HPV16 ORFs didn’t have strong codon usage bias. Most of the HPV16 ORFs were mainly governed by natural selection pressure such as translational pressure, except for L2. HPV16 only shared some of the preferred codons with human, which might help reduce competition in translational resources. These findings may help increase our understanding of the heterogeneity between HPV16 lineages and sublineages, and the adaptation mechanism of HPV in human cells, which might facilitate HPV classification and improve vaccine development and application.
Molecular mechanism regulating transcriptional control of the hig toxin-antitoxin locus of antibiotic-resistance plasmid Rts1 from Proteus vulgaris
Authors: Pavelich Ian , Schureck Marc A. , Wang Dongxue , Hoffer Eric D. , Boamah Michelle , Onuoha Nina , Miles Stacey J. , Okafor C. Denise , Dunham Christine M.
Published: March 2021

Regulation of ubiquitous bacterial type II toxin-antitoxin (TA) gene pairs occurs via a negative feedback loop whereby their expression is typically responsive to changing levels of toxins at the transcriptional level similar to a molecular rheostat. While this mechanism can explain how certain TA complexes are regulated, accumulating evidence suggests diversity in this regulation. One system for which the negative feedback loop is not well defined is the plasmid-encoded HigBHigA TA pair originally identified in a post-operative infection with antibiotic resistant Proteus vulgaris. In contrast to other type II TA modules, each hig operator functions independently and excess toxin does not contribute to increased transcription in vivo. Structures of two different oligomeric complexes of HigBHigA bound to its operator DNA reveal similar interactions are maintained suggesting plasticity in how hig is repressed. Consistent with this result, molecular dynamic simulations reveal both oligomeric states exhibit similar dynamics. Further, engineering a dedicated trimeric HigBHigA complex does not regulate transcriptional repression. We propose that HigBHigA functions via a simple on/off transcriptional switch regulated by antitoxin proteolysis rather than a molecular rheostat. The present studies thus expand the known diversity of how these abundant bacterial protein pairs are regulated.

IMPORTANCE

Bacteria respond to various stimuli by rapidly regulating gene expression to control growth. The diversity in how bacteria inhibit growth is exemplified by the abundance and diversity of toxin-antitoxin (TA) gene pairs. To tightly regulate their own expression, antitoxin proteins function as transcriptional autorepressors with additional regulation imparted by responsiveness of the system to toxin concentrations, similar to a molecular rheostat. However, some TAs do not appear to be responsive to changing levels of toxin. To expand our understanding of diverse TAs, we studied the regulation of a structurally distinct TA called host inhibition of growth (HigBA) originally discovered on the antibiotic resistance Rts1 plasmid associated with Proteus vulgaris. We find that the hig operon is regulated via a simple on/off transcriptional switch that is incalcitrant to changing toxin levels. These results expand the known mechanistic diversity of how TA pairs regulate their expression.
Insights from the first genome assembly of Onion (Allium cepa)
Authors: Finkers Richard , van Kaauwen Martijn , Ament Kai , Burger-Meijer Karin , Egging Raymond , Huits Henk , Kodde Linda , Kroon Laurens , Shigyo Masayoshi , Sato Shusei , Vosman Ben , van Workum Wilbert , Scholten Olga
Published: March 2021

Onion is an important vegetable crop with an estimated genome size of 16Gb. We describe the de novo assembly and ab initio annotation of the genome of a doubled haploid onion line DHCU066619, which resulted in a final assembly of 14.9 Gb with a N50 of 461 Kb. Of this, 2.2 Gb was ordered into 8 pseudomolecules using five genetic linkage maps. The remainder of the genome is available in 89.8 K scaffolds. Only 72.4% of the genome could be identified as repetitive sequences and consist, to a large extent, of (retro) transposons. In addition, an estimated 20% of the putative (retro) transposons had accumulated a large number of mutations, hampering their identification, but facilitating their assembly. These elements are probably already quite old. The ab initio gene prediction indicated 540,925 putative gene models, which is far more than expected, possibly due to the presence of pseudogenes. Of these models, 86,073 showed similarity to published proteins (UNIPROT). No gene rich regions were found, genes are uniformly distributed over the genome. Analysis of synteny with A. sativum (garlic) showed collinearity but also major rearrangements between both species. This assembly is the first high-quality genome sequence available for the study of onion and will be a valuable resource for further research.
Political connection, political promotion and corporate environmental information disclosure in China
Authors: Li Yuxuan , Wong Christina W.Y. , Miao Xin
Published: March 2021

Purpose

This study aims to examine how the political career concerns of top executives affect corporate environmental practices.

Design/methodology/approach

Based on rent-seeking theory, this work uses empirical analysis to investigate the impact of top executives’ political connection and political promotion on corporate environmental information disclosure (EID). Data were collected from Chinese listed firms in heavily polluting industries in the Shanghai Stock Market in 2014–2016.

Findings

The results reveal that the highly politically connected top executives are more likely to be promoted in their political positions than their counterparts. However, the firms under the management of these highly politically connected executives show low level of EID. The results suggest that the political motivations of top executives with political connection hinders corporate EID.

Originality/value

This paper extends literature system about the impact of executives' rent-seeking on corporate EID by examining the informal mechanisms in terms of political connection and political promotion. It provides insights for studies of corporate environmental strategies and governmental environmental responsibility.
Do females in audit firm governance affect firm performance? Findings from Turkey
Authors: Ocak Murat
Published: March 2021

Purpose

This study aims to contribute to the literature by offering a different sector and emphasising the importance of females in audit firm (AF) governance on audit firm performance (AFP).

Design/methodology/approach

Ordinary least squares (OLS) and instrument variables regression (IVREG) with two-stage least squares are used to test the paper’s hypotheses.

Findings

Both OLS and IVREG estimation results show that both the proportion of females and gender diversity at board and owner levels and the total number of shares of female owners seem to enhance the performance of AFs.

Practical implications

These results may be important for policymakers and regulators to set a quota for women’s representation on AF governance or decide arrangements for women in AFs as in the regulations for the high hierarchical levels of other corporate firms.

Originality/value

This paper extends the current literature in the context of AFs in Turkey, positing that females in AF governance might enhance performance to a great extent.
Building a bridge between adaptive capacity and adaptive potential to understand responses to environmental change
Authors: Seaborn Travis , Griffith David , Kliskey Andrew , Caudill Christopher C.
Published: March 2021

Adaptive capacity is a topic at the forefront of environmental change research with roots in both social, ecological, and evolutionary science. It is closely related to the evolutionary biology concept of adaptive potential. In this systematic literature review, we: (1) summarize the history of these topics and related fields; (2) assess relationship(s) between the concepts among disciplines and the use of the terms in climate change research, and evaluate methodologies, metrics, taxa biases, and the geographic scale of studies; and (3) provide a synthetic conceptual framework to clarify concepts. Bibliometric analyses revealed the terms have been used most frequently in conservation and evolutionary biology journals, respectively. There has been a greater growth in studies of adaptive potential than adaptive capacity since 2001, but a greater geographical extent of adaptive capacity studies. Few studies include both, and use is often superficial. Our synthesis considers adaptive potential as one process contributing to adaptive capacity of complex systems, notes “sociological” adaptive capacity definitions include actions aimed at desired outcome (i.e., policies) as a system driver whereas “biological” definitions exclude such drivers, and suggests models of adaptive capacity require integration of evolutionary and social–ecological system components.
Distinguishing veterans with suicidal ideation from suicide attempt history: The role of emotion reactivity
Authors: Gromatsky Molly , Edwards Emily R. , Sullivan Sarah R. , Goodman Marianne , Hazlett Erin A.
Published: March 2021

Introduction

Growing evidence suggests emotion reactivity—sensitivity and intensity of emotional experience—may represent a diathesis for suicide risk. However, our understanding of its ability to differentiate risk for suicidal ideation (SI) from suicide attempt (SA) is limited.

Method

This study compares Veterans with SI (n = 81) to Veterans with SA (n = 177) history on factors relevant to emotion reactivity to determine which variable(s) best differentiate groups. Variables examined are multimodal: (a) self‐report: childhood trauma, combat exposure; (b) clinician‐assessed: non‐suicidal self‐injury (NSSI), structured diagnostic interview of psychopathology; and (c) psychophysiological: affect‐modulated startle (AMS; proxy for amygdala reactivity and emotion reactivity) to unpleasant pictures was examined in a subset (n = 90).

Results

SA history was independently predicted by NSSI history, MDD, PTSD, and SUD diagnosis. Childhood trauma and combat exposure did not differentiate groups. The composite risk index demonstrated good accuracy (AUC=0.71, sensitivity=0.90, specificity=0.49). Only AMS independently predicted SA history when added to the model and accuracy was improved (AUC=0.82, sensitivity=0.85, specificity=0.56).

Conclusion

NSSI history, MDD, PTSD, and SUD diagnosis may be salient risk factors for this population. However, emotion reactivity is a more parsimonious predictor of SA history among Veterans suggesting it is an important treatment target among Veterans with SI.
A Rapid Recursive Experimental Approach to Structure/Control Re-Design
Authors: Pil Anton , Asada Haruhiko
Published: March 2021

This paper introduces an experimental recursive method for simultaneously changing both the mechanical structure and control design of mechatronic systems in order to improve the system’s overall performance. The method improves a system’s closed-loop control specifications through recursive concurrent structure reinforcement and control gain optimization. By using a process of structural reinforcement, a single prototype structure can be used repeatedly until the system performance goals are achieved. To determine the optimal incremental structure changes, a recursive algorithm based on a gradient descent method and a parameter estimation theory is employed. After the incremental structure reinforcements are applied, the control parameters are optimized with respect to multiple control specifications. Next, the resulting system incorporating the structure and control changes is tested and compared with the desired level of performance. The entire process consisting of experimental evaluation, data analysis, and structure reinforcement is repeated until the system performance achieves the desired level. Simulation experiments are successful in changing both the structural and control parameters of a simplified positioning system and show improvement in the system’s overall settling time.
A Probabilistic Tolerance Allocation Method for Dynamic Mechanical Systems With Periodic Response and Discontinuous Forcing Functions
Authors: Zhang F. , Gilmore B. J. , Sinha A.
Published: March 2021

Tolerance allocation standards do not exist for mechanical systems whose response are time varying and are subjected to discontinuous forcing functions. Previous approaches based on optimization and numerical integration of the dynamic equations of motion encounter difficulty with determining sensitivities around the force discontinuity. The Alternating Frequency/Time approach is applied here to capture the effect of the discontinuity. The effective link length model is used to model the system and to account for the uncertainties in the link length, radial clearance and pin location. Since the effective link length model is applied, the equations of motion for the nominal system can be applied for the entire analysis. Optimization procedure is applied to the problem where the objective is to minimize the manufacturing costs and satisfy the constraints imposed on mechanical errors and design variables. Examples of tolerance allocation are presented for a single cylinder internal combustion engine.
A Heuristic Method for Two-Dimensional Layout Problems
Authors: Zhang Xiong , Zhou Ji
Published: March 2021

This paper presents a method for an often encountered two-dimensional layout problem in the shipbuilding and manufacture industries. For a ordered set of irregular as well as rectangular pieces, the system produces rectangles called modules for the pieces at first, and then places these modules into given rectangular sheets of fixed dimensions such that the number of sheets used is minimized. The system also provides the user with an interaction procedure in order to make itself as flexible as possible. This heuristic method has been implemented on IBM PC/AT 486 and compatible computers and is supported by AutoCAD system.
Kinematic Analysis of Tendon Driven Mechanisms Using Signal Flow Graphs
Authors: Chew M. , Escobedo-Torres J. , Huerta-Ochoa R.
Published: March 2021

The application of signal flow graphs has been applied to the kinematic analysis of tendon driven mechanisms. Signal flow graphs have been used in the many areas particularly in the area of control for determining the closed-loop function of a control system. An application of this approach brings the kinematic analysis of tendon driven mechanisms a step towards dynamic analysis and control of these same mechanisms, all within the same framework. Rules directly relating to the application of this technique to tendon driven mechanisms have been developed along with a stepwise description of the construction of signal flow graphs. The resulting graphs permit a direct solution to the kinematic relationships between the output and the input to the mechanism.
Preliminary Robust Design Using Advanced Spreadsheet Modeling Techniques
Authors: Eggert R. J.
Published: March 2021

Robust design methods such as the worst case, random variable calculus and Monte Carlo simulation are useful in minimizing undesirable effects on product reliability, quality and dependability. While the Monte Carlo method provides meaningful qualitative and quantitative results, it has been difficult to implement without specialized computer software. A new preliminary robust design methodology has been developed which overcomes this problem. New spreadsheet features and advanced modeling techniques are presented which implement the Monte Carlo simulation approach. The preliminary robust design of a transmission shaft is presented which illustrates the new modeling techniques.
Determination of Residual Stresses Induced by Hardened Steel Turning Using Finite Element Methods
Authors: Yang Guang , Tite Caroline Norma Jane , Smith Graham Thomas , Hope Anthony David , Noroozi Siamak
Published: March 2021

A method of using the finite element mode to predict the residual stresses on the surface of machined hardened steel is proposed. The proposed model is based on the analysis of strain relaxation data obtained from the measurement of residual stresses by material removal methods involving two stages; 1). experimental determination of the thermal residual stresses produced during heat treatment 2). experimental determination of the resultant residual stress on the machined surface due to the interaction between thermal stress relief and the machining stresses induced. The proposed finite element model was used to determine the relationship between the two types of residual stress within the machined surface region of a workpiece. It was found that the remaining residual stresses are determined mainly by stress release rather than induction. Such a finite element approach aims at an improvement in accuracy and reduction in the number of experiments required to determine the nature of residual stresses. Furthermore, it could provide an improved qualitative assessment of residual stresses when applied to hardened steel turning.
Application of the Thermoelastic Effect to the Stress Analysis of Structural Adhesive Connections
Authors: Gonçalves J. P. M. , Oliveira F. M. F. , de Castro P. M. S. T. , Fernandes A. A.
Published: March 2021

The experimental stress analysis technique using the thermoelastic effect is quite recent. Besides being a non-contact method, the technique is able to produce a full field analysis. These attributes, associated with the possibility of application to structures or components in their operating environment, make the technique appealing for use in an industrial context.

The thermoelastic effect is the change in temperature arising from the change in the stress state of a solid. The stress analysis technique using this effect measures the infra-red radiation emitted from a modification in its stress state. The applicability of the relationship between change in temperature and change in the stress state, as described in the theory of thermoelasticity, requires the existence of adiabatic conditions. Thus, the body to be studied must be subjected to a cyclic loading of a frequency sufficient to ensure those conditions.

Adhesives are being used increasingly in more demanding applications not only in non-load carrying situations but also in structural applications as an alternative to other joining techniques. The use of adhesives in structural applications requires understanding the global behavior of structures as well as the behavior of the adhesive connections. Stress analysis of those connections is an important step towards that goal.

Lap-shear joints are a type of adhesive connections widely used in industrial applications, namely, in the aerospace and automotive industries. In this study, stress analyses of these connections were performed.

The experimental stress analysis technique using the thermoelastic effect was used to determine the stress state at a surface of adhesive lap-shear joints. The results were compared with finite element analyses of the same joints.
Set Based Hierarchical Design: A Constraint Satisfaction Approach
Authors: Bliek Christian
Published: March 2021

Many are the literature reviews where constraint satisfaction is rejected as a candidate solution for design automation. Some point to the combinatorial complexity associated with the solution of large constraint satisfaction problems, others claim it is inadequate to handle the uncertainty prominent in engineering design. In this paper we present a new approach in which hierarchical decomposition techniques exploit sensitivity to reduce combinatorial complexity and uncertainty is modeled using conservative enclosures of sets of possible solutions.
Activity Analysis: Simplifying Optimal Design Problems Through Qualitative Partitioning
Authors: Williams Brian C. , Cagan Jonathan
Published: March 2021

Activity analysis is introduced as a means to strategically cut away subspaces of a design problem that can quickly be ruled out as suboptimal. This results in focused regions of the space in which additional symbolic or numerical analysis can take place. Activity analysis is derived from a qualitative abstraction of the Karush-Kuhn-Tucker conditions of optimality, used to partition an optimization problem into regions which are nonstationary and qualitatively stationary (qstationary). Activity analysis draws from the fields of gradient-based optimization, conflict-based approaches of combinatorial satisficing search, and monotonicity analysis.
Functional Tolerancing: A Design for Manufacturing Methodology
Authors: Srinivasan R. S. , Wood Kristin L. , McAdams Daniel
Published: March 2021

The problem addressed in this paper is the development of a physico-mathematical basis for mechanical tolerances. The lack of such a basis has fostered a decoupling of design (function) and manufacturing. The groundwork for a tolerancing methodology is laid by a model of profile errors, whose components are justified by physical reasoning and estimated using mathematical tools. The methodology is then presented as an evolutionary procedure. This procedure harnesses the various tools to analyze profiles in terms of a minimum set of profile parameters and to re-generate them from the parameters. This equips the designer with a rational means for estimating performance prior to manufacturing, hence integrating design and manufacturing. The utility of the functional tolerancing methodology is demonstrated with performance simulations of a lathe-head-stock design, focusing on gear transmission with synthesized errors.
Manufacturability: Metrics and Perceptions
Authors: Hight Tim , Hornberger Lee , Last Melissa
Published: March 2021

A project was undertaken at Sun Microsystems, Inc. to benchmark DFMA on two workstations. Using both standard DFMA metrics and indirect process metrics, as well as interviews and discussions with development team members, the two products were found to be similar. Incongruities were noted, however, between perceptions of the products and the results of the analysis. Perceptions significantly impacted design decisions in the absence of readily available DFMA metrics.
The Fast Resource Evaluation Grid
Authors: Desa S. , Kannapan Srikanth
Published: March 2021

The success of product design, development and delivery in a technological enterprise crucially depends on the optimal integration of enterprise resources. The Fast Resource Evaluation Grid permits the comprehension of the strengths and importances of these resources as a rational basis for the allocation of effort to close resource gaps.
Design and Implementation of a Virtual Groupware for Layout Decision Problems
Authors: Banerjee A. , Banerjee P. , Mehrotra S.
Published: March 2021

An exploratory virtual reality-based groupware architecture is described as a computerized platform for simultaneously addressing qualitative and quantitative factors in layout problems. The motivation is to narrow this gap between the output of a computerized layout design optimization method and its implementation in practice. The steps involved in formulating and modeling the problem and in implementing a solution methodology are outlined. As part of our ongoing research, the groupware is currently designed to take input from a computerized optimization model for layout design and detailed layout design information such as 3-dimensional geometric, topological, graphics (rendering and texture mapping) and motion information. The groupware can have upto four members in a group who can collaboratively interact to manipulate a detailed layout Pairwise exchange and repositioning of individual layout objects are currently considered.
Design and Analysis of Fluidless Cooling Devices for High Speed Machining
Authors: Billatos Samir B. , Basaly Nadia A.
Published: March 2021

In high speed machining, the generated heat produces very high temperatures at the tool-work interface. Heat generated at the cutting area may shorten tool life, damage work piece surface, affect surface characteristics, and hence increase production cost. To deal with these problems, cutting fluids are used. Unfortunately, these fluids cause harmful effects to the operators and serious problems of pollution to the environment. Therefore, a new approach is developed to reduce the cutting tool temperature without using external coolants, and thus considerably reduce the amount of the hazardous waste being disposed to the environment. It removes a portion of the generated heat from the tool-work interface by flowing water in a closed cooling cycle system. The approach was analyzed and verified using Finite Element Analysis. Results were compared to the dry and wet cutting cases obtained from literature, and it was found that temperatures on the flank and rake faces of the tool can be lowered, and the overheated area of the tool tip, and consequently its wear, can be reduced significantly.