bluuebunny/crossref_metadata_2025 huggingface dataset:
Configuration Space Exploration for Digital Printing Systems
Authors: Denkers Jasper , Brunner Marvin , van Gool Louis , Visser Eelco
Published: December 2021

Within the printing industry, much of the variety in printed applications comes from the variety in finishing. Finishing comprises the processing of sheets of paper after being printed, e.g. to form books. The configuration space of finishers, i.e. all possible configurations given the available features and hardware capabilities, are large. Current control software minimally assists operators in finding useful configurations. Using a classical modelling and integration approach to support a variety of configuration spaces is suboptimal with respect to operatability, development time, and maintenance burden.

In this paper, we explore the use of a modeling language for finishers to realize optimizing decision making over configuration parameters in a systematic way and to reduce development time by generating control software from models.

We present CSX, a domain-specific language for high-level declarative specification of finishers that supports specification of the configuration parameters and the automated exploration of the configuration space of finishers. The language serves as an interface to constraint solving, i.e., we use low-level SMT constraint solving to find configurations for high-level specifications. We present a denotational semantics that expresses a translation of CSX specifications to SMT constraints. We describe the implementation of the CSX compiler and the CSX programming environment (IDE), which supports well-formedness checking, inhabitance checking, and interactive configuration space exploration. We evaluate CSX by modelling two realistic finishers. Benchmarks show that CSX has practical performance (<1s) for several scenarios of configuration space exploration.
Prediction of chronic thromboembolic pulmonary hypertension with standardised evaluation of initial computed tomography pulmonary angiography performed for suspected acute pulmonary embolism
Authors: Boon Gudula J. A. M. , Ende-Verhaar Yvonne M. , Beenen Ludo F. M. , Coolen Johan , Delcroix Marion , Golebiowski Marek , Huisman Menno V. , Mairuhu Albert T. A. , Meijboom Lilian J. , Middeldorp Saskia , Pruszczyk Piotr , van Rooden Cornelis J. , Vonk Noordegraaf Anton , Kroft Lucia J. M. , Klok Frederikus A.
Published: December 2021

Objectives

Closer reading of computed tomography pulmonary angiography (CTPA) scans of patients presenting with acute pulmonary embolism (PE) may identify those at high risk of developing chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to validate the predictive value of six radiological predictors that were previously proposed.

Methods

Three hundred forty-one patients with acute PE were prospectively followed for development of CTEPH in six European hospitals. Index CTPAs were analysed post hoc by expert chest radiologists blinded to the final diagnosis. The accuracy of the predictors using a predefined threshold for ‘high risk’ (≥ 3 predictors) and the expert overall judgment on the presence of CTEPH were assessed.

Results

CTEPH was confirmed in nine patients (2.6%) during 2-year follow-up. Any sign of chronic thrombi was already present in 74/341 patients (22%) on the index CTPA, which was associated with CTEPH (OR 7.8, 95%CI 1.9–32); 37 patients (11%) had ≥ 3 of 6 radiological predictors, of whom 4 (11%) were diagnosed with CTEPH (sensitivity 44%, 95%CI 14–79; specificity 90%, 95%CI 86–93). Expert judgment raised suspicion of CTEPH in 27 patients, which was confirmed in 8 (30%; sensitivity 89%, 95%CI 52–100; specificity 94%, 95%CI 91–97).

Conclusions

The presence of ≥ 3 of 6 predefined radiological predictors was highly specific for a future CTEPH diagnosis, comparable to overall expert judgment, while the latter was associated with higher sensitivity. Dedicated CTPA reading for signs of CTEPH may therefore help in early detection of CTEPH after PE, although in our cohort this strategy would not have detected all cases.

Key Points

• Three expert chest radiologists re-assessed CTPA scans performed at the moment of acute pulmonary embolism diagnosis and observed a high prevalence of chronic thrombi and signs of pulmonary hypertension.

• On these index scans, the presence of ≥ 3 of 6 predefined radiological predictors was highly specific for a future diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH), comparable to overall expert judgment.

• Dedicated CTPA reading for signs of CTEPH may help in early detection of CTEPH after acute pulmonary embolism.
SAF-A mutants disrupt chromatin structure through dominant negative effects on RNAs associated with chromatin
Authors: Kolpa Heather J. , Creamer Kevin M. , Hall Lisa L. , Lawrence Jeanne B.
Published: December 2021

Here we provide a brief review of relevant background before presenting results of our investigation into the interplay between scaffold attachment factor A (SAF-A), chromatin-associated RNAs, and DNA condensation. SAF-A, also termed heterogenous nuclear protein U (hnRNP U), is a ubiquitous nuclear scaffold protein that was implicated in XIST RNA localization to the inactive X-chromosome (Xi) but also reported to maintain open DNA packaging in euchromatin. Here we use several means to perturb SAF-A and examine potential impacts on the broad association of RNAs on euchromatin, and on chromatin compaction. SAF-A has an N-terminal DNA binding domain and C-terminal RNA binding domain, and a prominent model has been that the protein provides a single-molecule bridge between XIST RNA and chromatin. Here analysis of the impact of SAF-A on broad RNA-chromatin interactions indicate greater biological complexity. We focus on SAF-A’s role with repeat-rich C0T-1 hnRNA (repeat-rich heterogeneous nuclear RNA), shown recently to comprise mostly intronic sequences of pre-mRNAs and diverse long non-coding RNAs (lncRNAs). Our results show that SAF-A mutants cause dramatic changes to cytological chromatin condensation through dominant negative effects on C0T-1 RNA’s association with euchromatin, and likely other nuclear scaffold factors. In contrast, depletion of SAF-A by RNA interference (RNAi) had no discernible impact on C0T-1 RNA, nor did it cause similarly marked chromatin changes as did three different SAF-A mutations. Overall results support the concept that repeat-rich, chromatin-associated RNAs interact with multiple RNA binding proteins (RBPs) in a complex dynamic meshwork that is integral to larger-scale chromatin architecture and collectively influences cytological-scale DNA condensation.
Clinical characteristics, treatment patterns and relapse in patients with clinical stage IS testicular cancer
Authors: Brandt Maximilian Peter , Ruf C. , Dieckmann K. P. , Syring I. , Ruckes C. , Nestler T. , Schmelz H. U. , Dotzauer R. , Hiester A. , Albers P. , Nettersheim D. , Bolenz C. , Loosen S. H. , Heidenreich A. , Pfister D. , Haferkamp A. , Zengerling F. , Paffenholz P. ,   GESRU Academics Testis, Penile Cancer Group, Brandt Maximilian Peter , Ruf C. , Syring I. , Nestler T. , Albers P. , Nettersheim D. , Zengerling F. , Paffenholz P.
Published: December 2021

Purpose

Clinical stage I (CSI) testicular germ cell tumors (TGCT) represents disease confined to the testis without metastasis and CSIS is defined as persistently elevated tumor markers (TM) after orchiectomy, indicating subclinical metastatic disease. This study aims at assessing clinical characteristics and oncological outcome in CSIS.

Methods

Data from five tertiary referring centers in Germany were screened. We defined correct classification of CSIS according to EAU guidelines. TM levels, treatment and relapse-free survival were assessed and differences between predefined groups (chemotherapy, correct/incorrect CSIS) were analyzed with Fisher’s exact and Chi-square test.

Results

Out of 2616 TGCT patients, 43 (1.6%) were CSIS. Thereof, 27 were correctly classified (cCSIS, 1.03%) and 16 incorrectly classified (iCSIS). TMs that defined cCSIS were in 12 (44.4%), 10 (37%), 3 (11.1%) and 2 (7.4%) patients AFP, ß-HCG, AFP plus ß-HCG and LDH, respectively. In the cCSIS group, six patients were seminoma and 21 non-seminoma. Treatment consisted of active surveillance, carboplatin-mono AUC7 and BEP (bleomycin, etoposide and cisplatin). No difference between cCSIS and iCSIS with respect to applied chemotherapy was found (p = 0.830). 5-year relapse-free survival was 88.9% and three patients (11%) in the cCSIS group relapsed. All underwent salvage treatment (3xBEP) with no documented death.

Conclusion

Around 1% of all TGCT were classified as cCSIS patients. Identification of cCSIS is of critical importance to avoid disease progression and relapses by adequate treatment. We report a high heterogeneity of treatment patterns, associated with excellent long-term survival irrespective of the initial treatment approach.
Intake of micronutrients and fatty acids of vegetarian, vegan, and omnivorous children (1–3 years) in Germany (VeChi Diet Study)
Authors: Weder Stine , Keller Markus , Fischer Morwenna , Becker Katja , Alexy Ute
Published: December 2021

Purpose

There is an ongoing debate whether vegetarian (VG) and especially vegan (VN) diets are nutritionally adequate in early childhood. Hence, the Vegetarian and Vegan Children Study (VeChi Diet Study) aimed to assess the food and nutrient intake of VG and VN infants.

Methods

The study examined the diets of 1–3-year-old VG, VN, and omnivorous (OM) children (n = 430). Dietary intake was assessed via a 3-day weighed dietary record and compared between groups using ANCOVA. Lifestyle data were collected using a questionnaire. Here, the results of micronutrient and fatty acid intakes are presented.

Results

Most nutrient intakes (with and without supplements) differed significantly between VN children and the two other groups, with a more favourable overall micronutrient intake in VN, followed by VG children, [e.g., the highest intake of vitamin E (8.3 mg/d vs. VG 7.4 mg/d and OM 5.1 mg/d), vitamin B1 (569 µg/d vs. VG 513 µg/d and OM 481 µg/d), folate (143 µg/d vs. VG 116 µg/d and OM 108 µg/d), magnesium (241 mg/d vs. VG 188 mg/d and OM 164 mg/d), and iron (8.9 mg/d vs. VG 7.3 mg/d and OM 6.0 mg/d)] as well as fat quality [highest intake of polyunsaturated fatty acids (8.7 E% vs. VG 6.9 E% and OM 4.5 E%) and lowest intake of saturated fatty acids (9.1 E% vs. VG 11.9 E% and OM 14.0 E%)]. In contrast, OM children had the highest intake of vitamin B2 (639 µg/d vs. VG 461 µg/d and VN 429 µg/d), calcium (445 mg/d vs. VG 399 mg/d and VN 320 mg/d), iodine (47 µg/d vs. VG 33 µg/d and VN 31 µg/d), and DHA (35.4 mg/d vs. VG 16.6 mg/d and VN 18.4 mg/d). Without supplementation, OM children had the highest average vitamin B12 intake (1.5 µg/d vs. VG 0.6 µg/d and VN 0.2 µg/d), whereas VN children had the highest average vitamin B12 intake with supplementation (73.8 µg/d vs. VG 1.3 µg/d and OM 1.7 µg/d). Without supplementation, none of the groups’ median intakes met the harmonised Average Requirement (h-AR) for vitamin D and iodine. Moreover, VG and VN children did not achieve h-ARs for vitamin B2, vitamin B12, and iron—if a low absorption of iron is anticipated; VN children also did not do so for calcium.

Conclusion

In early childhood, VN and VG diets can provide most micronutrients in desirable amounts and a preferable fat quality compared to an OM diet. Special focus should be paid to (potentially) critical nutrients, particularly vitamin D, iodine, and DHA for all children regardless of diet, as well as vitamin B2, vitamin B12, calcium, and iron for VG and VN children.

Trail registration

This study was registered with the German Clinical Trials Register (DRKS00010982) on (September 2, 2016).
Investigation of the well-dispersed magnetorheological oil-based suspension with superparamagnetic nanoparticles using modified split Hopkinson pressure bar
Authors: Osial Magdalena , Nowicki Michał , Klejman Ewa , Frąś Leszek
Published: December 2021

Magnetorheological (MR) fluids are classified as smart materials whose viscoplastic characteristics change under the magnetic field. They are widely applied for dynamic energy dissipation due to their rapid thickening under the external magnetic field. In this work, the core–shell suspension of superparamagnetic iron oxide-based nanoparticles was synthesized and dispersed in silicone oil. Much effort has been made to prepare suspension meeting requirements of MR fluid. The experimental squeezing flow response was studied using a modified split Hopkinson pressure bar (SHPB) with various shear rates. Tests with modified SHPB show that MR fluid rapidly responds to the compression thickening and forming chain-like structures. MR fluid dissipates the energy generated during compression stress tests. This study presents a simple and cost-effective synthesis way suitable for MR fluid formation for its dynamic energy dissipation application.
Genome-wide analysis of mitochondrial DNA copy number reveals loci implicated in nucleotide metabolism, platelet activation, and megakaryocyte proliferation
Authors: Longchamps R. J. , Yang S. Y. , Castellani C. A. , Shi W. , Lane J. , Grove M. L. , Bartz T. M. , Sarnowski C. , Liu C. , Burrows K. , Guyatt A. L. , Gaunt T. R. , Kacprowski T. , Yang J. , De Jager P. L. , Yu L. , Bergman A. , Xia R. , Fornage M. , Feitosa M. F. , Wojczynski M. K. , Kraja A. T. , Province M. A. , Amin N. , Rivadeneira F. , Tiemeier H. , Uitterlinden A. G. , Broer L. , Van Meurs J. B. J. , Van Duijn C. M. , Raffield L. M. , Lange L. , Rich S. S. , Lemaitre R. N. , Goodarzi M. O. , Sitlani C. M. , Mak A. C. Y. , Bennett D. A. , Rodriguez S. , Murabito J. M. , Lunetta K. L. , Sotoodehnia N. , Atzmon G. , Ye K. , Barzilai N. , Brody J. A. , Psaty B. M. , Taylor K. D. , Rotter J. I. , Boerwinkle E. , Pankratz N. , Arking D. E.
Published: December 2021

Mitochondrial DNA copy number (mtDNA-CN) measured from blood specimens is a minimally invasive marker of mitochondrial function that exhibits both inter-individual and intercellular variation. To identify genes involved in regulating mitochondrial function, we performed a genome-wide association study (GWAS) in 465,809 White individuals from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and the UK Biobank (UKB). We identified 133 SNPs with statistically significant, independent effects associated with mtDNA-CN across 100 loci. A combination of fine-mapping, variant annotation, and co-localization analyses was used to prioritize genes within each of the 133 independent sites. Putative causal genes were enriched for known mitochondrial DNA depletion syndromes (p = 3.09 × 10–15) and the gene ontology (GO) terms for mtDNA metabolism (p = 1.43 × 10–8) and mtDNA replication (p = 1.2 × 10–7). A clustering approach leveraged pleiotropy between mtDNA-CN associated SNPs and 41 mtDNA-CN associated phenotypes to identify functional domains, revealing three distinct groups, including platelet activation, megakaryocyte proliferation, and mtDNA metabolism. Finally, using mitochondrial SNPs, we establish causal relationships between mitochondrial function and a variety of blood cell-related traits, kidney function, liver function and overall (p = 0.044) and non-cancer mortality (p = 6.56 × 10–4).
Energy minimizers for an asymptotic MEMS model with heterogeneous dielectric properties
Authors: Laurençot Philippe , Nik Katerina , Walker Christoph
Published: December 2021

A model for a MEMS device, consisting of a fixed bottom plate and an elastic plate, is studied. It was derived in a previous work as a reinforced limit when the thickness of the insulating layer covering the bottom plate tends to zero. This asymptotic model inherits the dielectric properties of the insulating layer. It involves the electrostatic potential in the device and the deformation of the elastic plate defining the geometry of the device. The electrostatic potential is given by an elliptic equation with mixed boundary conditions in the possibly non-Lipschitz region between the two plates. The deformation of the elastic plate is supposed to be a critical point of an energy functional which, in turn, depends on the electrostatic potential due to the force exerted by the latter on the elastic plate. The energy functional is shown to have a minimizer giving the geometry of the device. Moreover, the corresponding Euler–Lagrange equation is computed and the maximal regularity of the electrostatic potential is established.
Diversity of carbapenem-resistant Klebsiella pneumoniae ST14 and emergence of a subgroup with KL64 capsular locus in the Arabian Peninsula
Authors: Mouftah Shaimaa F. , Pál Tibor , Higgins Paul G. , Ghazawi Akela , Idaghdour Youssef , Alqahtani Manaf , Omrani Ali S. , Rizvi Tahir A. , Sonnevend Ágnes
Published: December 2021

To understand the reasons of successful spread of carbapenem-resistant Klebsiella pneumoniae ST14 (CRKP-ST14) in countries of the Arabian Peninsula, the resistome, capsular locus, carbapenemase carrying plasmid types, and core genome of isolates from the region were compared to global isolates. Thirty-nine CRKP-ST14 strains isolated from 13 hospitals in the United Arab Emirates, Bahrain, and Saudi Arabia were selected for whole genome sequencing on Illumina MiSeq platform based on the variety of carbapenemase genes carried and plasmids bearing these genes. Their resistome, capsular locus, and core genome MLST were compared to 173 CRKP-ST14 genomes available in public databases. The selected 39 CRKP-ST14 produced either NDM-1, OXA-48, OXA-162, OXA-232, KPC-2, or co-produced NDM-1 and an OXA-48-like carbapenemase. cgMLST revealed three clusters: 16 isolates from five UAE cities (C1), 11 isolates from three UAE cities and Bahrain (C2), and 5 isolates from Saudi Arabia (C3), respectively, and seven singletons. Resistance gene profile, carbapenemase genes, and their plasmid types were variable in both C1 and C2 clusters. The majority of CRKP-ST14 had KL2, but members of the C2 cluster and two further singletons possessed KL64 capsular locus. Based on cgMLST comparison of regional and global isolates, CRKP-ST14 with KL64 from four continents formed a distinct cluster, suggesting a recent emergence and spread of this variant. Our findings confirmed clonal transmission coupled with likely horizontal gene transfer in carbapenem-resistant Klebsiella pneumoniae ST14. Dissemination of this genetically flexible, highly resistant clone warrants further monitoring.
Equivalent cyclic polygon of a euclidean travelling salesman problem tour and modified formulation
Authors: Herraiz A. , Gutierrez M. , Ortega-Mier M.
Published: December 2021

We define a geometric transformation of Euclidean Travelling Salesman Problem (TSP) tours that leads to a new formulation of the TSP. For every Euclidean TSP n-city tour, it is possible to construct an inscribed n-polygon (Equivalent Cyclic Polygon, ECP) such that the lengths of the edges are equal to the corresponding TSP tour links and follow the same sequence order. The analysis of the ECP elicits the possibility of defining a new objective function in terms of angles instead of distances. This modification opens the way to identify characterizing geometric parameters of the TSP as well as to explore new heuristics based on the inclusion of additional constraints. The experimentation with a set of cases shows promising results compared to the traditional compact formulations. The behavior of the ECP-based TSP formulations is better when the nodes of the TSP are randomly or evenly distributed.
Inverted Hierarchies on the Shop Floor: The Organisational Layer of Workarounds for Collaboration in the Metal Industry
Authors: Mörike Frauke
Published: December 2021

Workarounds, or practices that deviate from the official pathway to a target, are frequent phenomena in the organisational context. With respect to collaboration, they highlight an area of mismatch between normative versus lived work practices, and therefore depict a relevant research area deeply rooted in computer supported cooperative work (CSCW). Building on the theory of hierarchical opposition by Louis Dumont and empirical data collected through ethnographic research at a company classified as a small- and medium-sized enterprise (SME) in the German metal industry, this paper addresses the emergence of workarounds in collaborative work processes by setting them into the wider organisational context. The organisational layer of analysis reveals that workarounds emerge to cater for inversed information power relations and information asymmetries in the shop floor setting, which require communication to flow against the hierarchical slope between planning and execution functions. By applying an organisational lens to the concept of workarounds, this paper contributes a novel empirical analysis that confirms the value of workarounds as a source of insight into collaborative practices.
A large neighborhood search approach for the paint shop scheduling problem
Authors: Winter Felix , Musliu Nysret
Published: December 2021

Minimizing the setup costs caused by color changes is one of the main concerns for paint shop scheduling in the automotive industry. Yet, finding an optimized color sequence is a very challenging task, as a large number of exterior systems for car manufacturing need to be painted in a variety of different colors. Therefore, there is a strong need for efficient automated scheduling solutions in this area. Previously, exact and metaheuristic approaches for creating efficient paint shop schedules in the automotive supply industry have been proposed and evaluated on a publicly available set of real-life benchmark instances. However, optimal solutions are still unknown for many of the benchmark instances, and there is still a potential of reducing color change costs for large instances. In this paper, we propose a novel large neighborhood search approach for the paint shop scheduling problem. We introduce innovative exact and heuristic solution methods that are utilized within the large neighborhood search and show that our approach leads to improved results for large real-life problem instances compared to existing techniques. Furthermore, we provide previously unknown upper bounds for 14 benchmark instances using the proposed method.
IPSC-Derived Human Neurons with GCaMP6s Expression Allow In Vitro Study of Neurophysiological Responses to Neurochemicals
Authors: Galiakberova A. A. , Surin A. M. , Bakaeva Z. V. , Sharipov R. R. , Zhang Dongxing , Dorovskoy D. A. , Shakirova K. M. , Fisenko A. P. , Dashinimaev E. B.
Published: December 2021

The study of human neurons and their interaction with neurochemicals is difficult due to the inability to collect primary biomaterial. However, recent advances in the cultivation of human stem cells, methods for their neuronal differentiation and chimeric fluorescent calcium indicators have allowed the creation of model systems in vitro. In this paper we report on the development of a method to obtain human neurons with the GCaMP6s calcium indicator, based on a human iPSC line with the TetON–NGN2 transgene complex. The protocol we developed allows us quickly, conveniently and efficiently obtain significant amounts of human neurons suitable for the study of various neurochemicals and their effects on specific neurophysiological activity, which can be easily registered using fluorescence microscopy. In the neurons we obtained, glutamate (Glu) induces rises in [Ca2+]i which are caused by ionotropic receptors for Glu, predominantly of the NMDA-type. Taken together, these facts allow us to consider the model we have created to be a useful and successful development of this technology.
Executive equity incentives and opportunistic manager behavior: new evidence from a quasi-natural experiment
Authors: Nienhaus Martin
Published: December 2021

This study provides plausible causal evidence on the effect of executive equity incentives on opportunistic manager behavior. I exploit a unique setting created by the introduction of Financial Accounting Standard (FAS) 123R in 2005, which led to an exogenous increase in the cost of option pay, causing a substantial decline in option pay for some firms while leaving others largely unaffected. Using difference-in-differences analyses with a treatment group of firms that show a decline in option pay and two control groups, I find that the likelihood of a treatment firm meeting or beating analyst forecasts decreases by 14–20%. The results show that the relatively high levels of meet-or-beat before FAS 123R were largely driven by real activities manipulation such as abnormal asset sales and sales manipulation to beat analysts’ benchmarks, while accrual manipulation and analyst management were less relevant. Together, the results suggest that equity incentives encourage opportunistic actions to meet or beat earnings expectations, and a decline in option pay results in a decline in earnings management to meet earnings expectations.
The 2021 chemistry Nobel laureates and asymmetric organocatalysis
Authors: Hargittai Istvan
Published: December 2021

The 2021 Nobel Prize in Chemistry was awarded jointly to Benjamin List and David MacMillan “for the development of asymmetric organocatalysis.” This choice was remarkable for a number of reasons. It singled out a very “chemical” discovery, whereas in recent years, the chemistry prizes often went for discoveries in biochemistry, and it singled out two relatively young men. The concept of asymmetric organocatalysis has been around since the late 1920s, and in the early 1970s, even proline was recognized as capable of playing the role of an enzyme. Nonetheless, asymmetric organocatalysis has found major applications since about the year 2000 due to the discoveries and activities of the new laureates and their colleagues.
Hamiltonian energy and coexistence of hidden firing patterns from bidirectional coupling between two different neurons
Authors: Njitacke Zeric Tabekoueng , Koumetio Bernard Nzoko , Ramakrishnan Balamurali , Leutcho Gervais Dolvis , Fozin Theophile Fonzin , Tsafack Nestor , Rajagopal Kartikeyan , Kengne Jacques
Published: December 2021

In this paper, bidirectional-coupled neurons through an asymmetric electrical synapse are investigated. These coupled neurons involve 2D Hindmarsh–Rose (HR) and 2D FitzHugh–Nagumo (FN) neurons. The equilibria of the coupled neurons model are investigated, and their stabilities have revealed that, for some values of the electrical synaptic weight, the model under consideration can display either self-excited or hidden firing patterns. In addition, the hidden coexistence of chaotic bursting with periodic spiking, chaotic spiking with period spiking, chaotic bursting with a resting pattern, and the coexistence of chaotic spiking with a resting pattern are also found for some sets of electrical synaptic coupling. For all the investigated phenomena, the Hamiltonian energy of the model is computed. It enables the estimation of the amount of energy released during the transition between the various electrical activities. Pspice simulations are carried out based on the analog circuit of the coupled neurons to support our numerical results. Finally, an STM32F407ZE microcontroller development board is exploited for the digital implementation of the proposed coupled neurons model.
Influence of dressing strategy on tool wear and performance behavior in grinding of forming tools with toric grinding pins
Authors: Denkena Berend , Krödel-Worbes Alexander , Keitel Michael , Wolters Philipp
Published: December 2021

The performance of grinding tools in grinding processes and the resulting surface and subsurface properties depend on various factors. The condition of the grinding tool after dressing is one of these factors. However, the influence of the dressing process on the condition of the grinding tool depends on the selected process parameters and is difficult to predict. Therefore, this paper presents an approach to describe the influence of the dressing process on tool wear of toric grinding pins and the resulting subsurface modification. For this purpose, toric grinding pins with a vitrified bond were dressed with two different strategies and the wear and operational behavior were investigated when grinding AISI M3:2 tool steel with two different grinding strategies. In general, the investigations have shown that the dressing process influences the performance and wear behavior differently depending on the grinding strategy used. The degree of clogging is influenced by the geometric contact sizes. In the case of small engagement cross sections with simultaneously large contact lengths the thermal tool load is distributed over a small annular area of the tool and favors clogging. Crushing and additional transverse loading of the grains result in an almost clog-free tool surface. This also leads to a lower G-ratio. Crushing leads to an intensified decrease of the torus radii. The influence of the dressing strategy can also be observed in the induced residual stresses. Toric grinding pins dressed by crushing induce lower compressive residual stresses into the workpiece, which can be attributed to the self-sharpening effect. This effect reduces the mechanical and thermomechanical load of the workpiece during machining.
When the winner takes it all: online campaign factors influencing the success of donation-based crowdfunding for charitable causes
Authors: Salido-Andres Noelia , Rey-Garcia Marta , Alvarez-Gonzalez Luis Ignacio , Vazquez-Casielles Rodolfo
Published: December 2021

This research explores the extent to which campaign factors may influence the success of donation-based crowdfunding (DCF) promoted online with social purposes. Factors that may explain the success of online fundraising campaigns for social causes are firstly identified from previous literature and linked to DCF campaigns through a set of hypotheses: disclosure, imagery, updating, and spreadability. Following, their explanatory capacity is measured through quantitative analysis (logistic regression) based on 360 all-or-nothing campaigns fostered by nonprofits through an online platform. Results confirm the high explanatory capacity of determinants related to the updating and spreadability of the campaign. However, factors related to the disclosure and imagery do not influence their success. This research suggests that the success of online campaigns is closely related to share and update transparent information of those details that contributors deem relevant. Implications are drawn for the effective technical design and management of DCF campaigns channeled through digital media, and specifically for the engagement with potential online communities of funders in digital platforms.
School-Based Mental Health Promotion and Early Intervention Programs in New South Wales, Australia: Mapping Practice to Policy and Evidence
Authors: Laurens Kristin R. , Graham Linda J. , Dix Katherine L. , Harris Felicity , Tzoumakis Stacy , Williams Kate E. , Schofield Jill M. , Prendergast Traci , Waddy Neale , Taiwo Mary , Carr Vaughan J. , Green Melissa J.
Published: December 2021

Limited empirical evidence is available regarding the uptake and effectiveness of school-based mental health and wellbeing programs implemented in Australian schools. This study aimed to characterise the delivery of programs in primary (elementary) schools across New South Wales, Australia, and to assess this information against published ratings of program effectiveness. Delivery of programs in four health-promoting domains—creating a positive school community; teaching social and emotional skills; engaging the parent community; and supporting students experiencing mental health difficulties—were reported by 597 school principals/leaders via online survey. Although three quarters of principals reported implementing at least one program, many of these programs were supported by little or no evidence of effectiveness. There was also variability in the use of evidence-based programs across the four domains. Findings indicate a need to provide educators with improved support to identify, implement, and evaluate effective evidenced-based programs that promote student mental health.
Utilizing Ultrasonic Waves in the Investigation of Contact Stresses, Areas, and Embedment of Spheres in Manufactured Materials Replicating Proppants and Brittle Rocks
Authors: Bou-Hamdan Kamel Fahmi , Abbas Azza Hashim
Published: December 2021

In the oil and gas industry, hydraulic fracturing (HF) is a common application to create additional permeability in unconventional reservoirs. Using proppant in HF requires understanding the interactions with rocks such as shale, and the mechanical aspects of their contacts. However, these studies are limited in literature and inconclusive. Therefore, the current research aims to apply a novel method, mainly ultrasound, to investigate the proppant embedment phenomena for different rocks. The study used proppant materials that are susceptible to fractures (glass) and others that are hard and do not break (steel). Additionally, the materials used to represent brittle shale rocks (polycarbonate and phenolic) were based on the ratio of elastic modulus to yield strength (E/Y). A combination of experimental and numerical modeling was used to investigate the contact stresses, deformation, and vertical displacement. The results showed that the relation between the stresses and ultrasound reflection coefficient follows a power-law equation, which validated the method application. From the experiments, plastic deformation was encountered in phenolic surfaces despite the corresponding contacted material. Also, the phenolic stresses showed a difference compared to polycarbonate for both high and low loads, which is explained by the high attenuation coefficient of phenolic that limited the quality of the reflected signal. The extent of vertical displacements surrounding the contact zone was greater for the polycarbonate materials due to the lower E/Y, while the phenolic material was limited to smaller areas not exceeding 50% of polycarbonate for all tested load conditions. Therefore, the study confirms that part of the contact energy in phenolic material was dissipated in the plastic deformation, indicating greater proppant embedment, and leading to a loss in fracture conductivity for rocks of higher E/Y.
Interfacial Engineering Strategy for High-Performance Zn Metal Anodes
Authors: Li Bin , Zhang Xiaotan , Wang Tingting , He Zhangxing , Lu Bingan , Liang Shuquan , Zhou Jiang
Published: December 2021

Due to their high safety and low cost, rechargeable aqueous Zn-ion batteries (RAZIBs) have been receiving increased attention and are expected to be the next generation of energy storage systems. However, metal Zn anodes exhibit a limited-service life and inferior reversibility owing to the issues of Zn dendrites and side reactions, which severely hinder the further development of RAZIBs. Researchers have attempted to design high-performance Zn anodes by interfacial engineering, including surface modification and the addition of electrolyte additives, to stabilize Zn anodes. The purpose is to achieve uniform Zn nucleation and flat Zn deposition by regulating the deposition behavior of Zn ions, which effectively improves the cycling stability of the Zn anode. This review comprehensively summarizes the reaction mechanisms of interfacial modification for inhibiting the growth of Zn dendrites and the occurrence of side reactions. In addition, the research progress of interfacial engineering strategies for RAZIBs is summarized and classified. Finally, prospects and suggestions are provided for the design of highly reversible Zn anodes.
300 Problems in Special and General Relativity
Authors: Blennow Mattias , Ohlsson Tommy
Published: December 2021

Einstein's theories of special relativity and general relativity form a core part of today's undergraduate (or Masters-level) physics curriculum. This is a supplementary problem book or student's manual, consisting of 150 problems in each of special and general relativity. The problems, which have been developed, tested and refined by the authors over the past two decades, are a mixture of short-form and multi-part extended problems, with hints provided where appropriate. Complete solutions are elaborated for every problem, in a different section of the book; some solutions include brief discussions on their physical or historical significance. Designed as a companion text to complement a main relativity textbook, it does not assume access to any specific textbook. This is a helpful resource for advanced students, for self-study, a source of problems for university teaching assistants, or as inspiration for instructors and examiners constructing problems for their lectures, homework or exams.
Evolution of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) seroprevalence among employees of a US academic children’s hospital during coronavirus disease 2019 (COVID-19) pandemic
Authors: Fisher Brian T. , Sharova Anna , Boge Craig L. K. , Gouma Sigrid , Kamrin Audrey , Blumenstock Jesse , Shuster Sydney , Gianchetti Lauren , Collins Danielle , Akaho Elikplim , Weirick Madison E. , McAllister Christopher M. , Bolton Marcus J. , Arevalo Claudia P. , Goodwin Eileen C. , Anderson Elizabeth M. , Christensen Shannon R. , Balamuth Fran , John Audrey R. Odom , Li Yun , Coffin Susan , Gerber Jeffrey S. , Hensley Scott E.
Published: December 2021

Objective:

To describe the cumulative seroprevalence of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) antibodies during the coronavirus disease 2019 (COVID-19) pandemic among employees of a large pediatric healthcare system.

Design, setting, and participants:

Prospective observational cohort study open to adult employees at the Children’s Hospital of Philadelphia, conducted April 20–December 17, 2020.

Methods:

Employees were recruited starting with high-risk exposure groups, utilizing e-mails, flyers, and announcements at virtual town hall meetings. At baseline, 1 month, 2 months, and 6 months, participants reported occupational and community exposures and gave a blood sample for SARS-CoV-2 antibody measurement by enzyme-linked immunosorbent assays (ELISAs). A post hoc Cox proportional hazards regression model was performed to identify factors associated with increased risk for seropositivity.

Results:

In total, 1,740 employees were enrolled. At 6 months, the cumulative seroprevalence was 5.3%, which was below estimated community point seroprevalence. Seroprevalence was 5.8% among employees who provided direct care and was 3.4% among employees who did not perform direct patient care. Most participants who were seropositive at baseline remained positive at follow-up assessments. In a post hoc analysis, direct patient care (hazard ratio [HR], 1.95; 95% confidence interval [CI], 1.03–3.68), Black race (HR, 2.70; 95% CI, 1.24–5.87), and exposure to a confirmed case in a nonhealthcare setting (HR, 4.32; 95% CI, 2.71–6.88) were associated with statistically significant increased risk for seropositivity.

Conclusions:

Employee SARS-CoV-2 seroprevalence rates remained below the point-prevalence rates of the surrounding community. Provision of direct patient care, Black race, and exposure to a confirmed case in a nonhealthcare setting conferred increased risk. These data can inform occupational protection measures to maximize protection of employees within the workplace during future COVID-19 waves or other epidemics.
Compressible potential flows around round bodies: Janzen–Rayleigh expansion inferences
Authors: Wallerstein Idan S. , Keshet Uri
Published: December 2021

The subsonic, compressible, potential flow around a hypersphere can be derived using the Janzen–Rayleigh expansion (JRE) of the flow potential in even powers of the incident Mach number

${\mathcal {M}}_\infty$

. JREs were carried out with terms polynomial in the inverse radius

$r^{-1}$

to high orders in two dimensions, but were limited to order

${\mathcal {M}}_\infty ^{4}$

in three dimensions. We derive general JRE formulae for arbitrary order, adiabatic index and dimension. We find that powers of

$\ln (r)$

can creep into the expansion, and are essential in the three-dimensional (3-D) sphere beyond order

${\mathcal {M}}_\infty ^{4}$

. Such terms are apparently absent in the 2-D disk, as we verify up to order

${\mathcal {M}}_\infty ^{100}$

, although they do appear in other dimensions (e.g. at order

${\mathcal {M}}_\infty ^{2}$

in four dimensions). An exploration of various 2-D and 3-D bodies suggests a topological connection, with logarithmic terms emerging when the flow is simply connected. Our results have additional physical implications. They are used to improve the hodograph-based approximation for the flow in front of a sphere. The symmetry-axis velocity profiles of axisymmetric flows around different prolate spheroids are approximately related to each other by a simple, Mach-independent scaling.
Abelian actions on compact nonorientable Riemann surfaces
Authors: Rodríguez Jesús
Published: December 2021

Given an integer
$g>2$
, we state necessary and sufficient conditions for a finite Abelian group to act as a group of automorphisms of some compact nonorientable Riemann surface of genus g. This result provides a new method to obtain the symmetric cross-cap number of Abelian groups. We also compute the least symmetric cross-cap number of Abelian groups of a given order and solve the maximum order problem for Abelian groups acting on nonorientable Riemann surfaces.
Stabilization and tracking control of an x-z type inverted pendulum system using Lightning Search Algorithm tuned nonlinear PID controller
Authors: Gürsel Özmen Nurhan , Marul Musa
Published: December 2021

Inverted pendulum systems (IPSs) are mostly used to demonstrate the control rules for keeping the pendulum at a balanced upright position due to a slight force applied to the cart system. This paper presents an application for nonlinear control of an x-z type IPS by using a proportional-integral-derivative (PID) controller with newly established evolutionary tuning method Lightning Search Algorithm (LSA). A single, double and triple PID controller system is tested with the conventional and the self-tuning controllers to get a better understanding of the performance of the given system. The mathematical modelling of the x-z type IPS, the theoretical explanation of the LSA and the simulation analysis of the x-z type IPS is put forward entirely. The LSA algorithm solves the optimization problem of PID controller in an evolutionary way. The most effective way of making comparisons is evaluating the performance results with a well-known optimization technique or with the previous accepted results. We have compared the system’s performance with particle swarm optimization and with a classical control study in the literature. According to the simulation results, LSA-tuned PID controller has the ability to decrease the overshoot better than the conventional-tuned controllers. Finally, it can be concluded that the LSA-supported PID can better stabilize the pendulum angle and track the reference better for non-disturbed and the slightly disturbed systems.
Heritage preservation in religious contexts. Disciplinary challenges for the Middle East and North Africa (MENA) region
Authors: Rico Trinidad
Published: December 2021

This article examines the ways in which global heritage discourse has operated across the Middle East and North Africa (MENA) region, from an ideological and historical perspective. Ideologically, I consider tensions between heritage preservation practice and religious traditions that share the same landscape or material culture. This discussion, which is relatively marginalized in the heritage literature, has an adverse effect on many attempts by heritage preservationists to mediate or resolve conflicts and contradictions surrounding this type of historic resource. Historically, I revisit the presence and inclusion of experts from the MENA region in the formative years of a global heritage ideology. In this discussion, I juxtapose the relative marginalization of the Middle East and North Africa in global heritage debates against the frequency with which sites and communities across this region are put in the spotlight of religion-driven heritage conflict. Addressing these two forms of (mis)representation, I aim to bring to the foreground the way in which heritage studies is implicated in the constructions of narratives about – not from or by – the MENA region.
A Combinatorial Approach to Reliable Quantitative Analysis of Small Nano-Sized Precipitates: A Case Study with α′ Precipitates in Fe–20 at% Cr Alloy
Authors: Sarkar Sudip Kumar , Shinde Deodatta , Sen Debasis , Biswas Aniruddha
Published: December 2021

The quantitative characterization of small nano-sized precipitates poses genuine challenges and is often deficient in accuracy due to the inherent limitations inevitably associated with the individual experimental techniques. A convenient solution is to utilize multiple complementary techniques. The present work demonstrates an effective way to reliably quantify nano-sized precipitates using a combination of complementary techniques of atom probe tomography (APT), small angle neutron scattering (SANS), and transmission electron microscopy (TEM). As a case study, the size (radius, r), number density (NP), volume fraction (ϕ), and chemical composition of Cr-rich α′ precipitates are determined in Fe–20 at% Cr alloy, thermally aged at 773 K for 1,000 h. This combinatorial approach utilizes the strength of each technique in such a way that the overall accuracy of quantitative precipitation analysis improves significantly. For example, the superior spatial resolution makes TEM the appropriate technique to estimate the size and size distribution of the precipitates, while APT provides the chemical composition. Similarly, SANS analysis incorporates both the size and the compositional information thus derived independently and provides statiscally averaged quantitative analysis overcoming the field-of-view limitations of both TEM and APT. This combinatorial approach improves the accuracy of quantification and provides the true representation of the microstructure.
Informal Care Provision and the Reduction of Economic Activity Among Mid-Life Carers in Great Britain – A Mixed-Methods Approach
Authors: Vlachantoni Athina , Wang Ning , Feng Zhixin , Falkingham Jane
Published: December 2021

Informal care provision is an integral part of the long-term care system. However, it has been shown to have negative effects on the carers’ economic activity, and understanding the mechanisms behind this is crucial for social policy design. This study provides new insight into mid-life carers’ decisions to reduce their economic activity through a convergent mixed-methods design. Quantitative analysis of a sample of 2,233 carers aged fifty from the National Child Development Study (NCDS) Wave 8 with follow up at age fifty-five, and qualitative analysis of in-depth interviews of forty-eight carers between 2008-2010, were used. The combined results indicate that being female, single never married, having financial issues, being an employee, and frequently meeting a parent are associated with economic activity reduction; the carers’ own perspectives further elucidate key factors, such as their value and identity, family structure, life course events, and care intensity, which affect their decisions.