bluuebunny/crossref_metadata_2025 huggingface dataset:
A 5–bit CMOS attenuator with low temperature and process variations for Ka‐band phased‐array applications
Authors: Lei Xin , Ye Liqun , Li Shengjun , Deng Chun , Fan Chao , Gui Xiaoyan , Yan Binyu , Liu Changjun
Published: June 2021

A 5‐bit CMOS attenuator with low temperature and process variations is presented employing the proposed optimization and compensation technique to achieve low root mean square (RMS) attenuation error and phase variation. The proposed design technique includes optimizing ratio of transistors and attenuation resistors to reduce the temperature and process variations, and utilizing a temperature and process compensation circuitry to further minimize the chip‐to‐chip and channel‐to‐channel variations. The presented attenuator is fabricated in a 55 nm CMOS process and achieves a maximum attenuation of 15.5 dB with 0.5 dB‐per‐step resolution. Measurement results show that the maximum RMS attenuation error is 0.6 dB and phase variation is less than ±2.2°, from −45 to 85°C and between different chips or channels within frequency range from 25 to 32 GHz. The core area is 0.32 × 0.5 mm2 excluding pads.
Two‐dimensional graphdiyne for passively Q‐switched Yb3+:Sc2SiO5 laser
Authors: Liu Xiaoqin , Guo Jia , Zheng Lihe , Liu Jie , Peng Qianqian , Ge Yanqi , Xu Jun
Published: June 2021

In this article, we demonstrate a laser diode pumped passively Q‐switched Yb3+:Sc2SiO5 (Yb:SSO) laser for the first time, applying a graphdiyne (GDY) saturable absorber which was prepared by the liquid phase exfoliation method. Utilizing the saturable absorption characteristic of the two‐dimensional GDY material, the pulsed Yb:SSO laser performances were investigated. The single pulse energy of 9.0 μJ and the peak power of 2.2 W were realized at an absorbed pump power of 3.151 W.
Multisite multivendor validation of a quantitative MRI and CT compatible fat phantom
Authors: Zhao Ruiyang , Hernando Diego , Harris David T. , Hinshaw Louis A. , Li Ke , Ananthakrishnan Lakshmi , Bashir Mustafa R. , Duan Xinhui , Ghasabeh Mounes Aliyari , Kamel Ihab R. , Lowry Carolyn , Mahesh Mahadevappa , Marin Daniele , Miller Jessica , Pickhardt Perry J. , Shaffer Jean , Yokoo Takeshi , Brittain Jean H. , Reeder Scott B.
Published: June 2021

Purpose

Chemical shift‐encoded magnetic resonance imaging enables accurate quantification of liver fat content though estimation of proton density fat‐fraction (PDFF). Computed tomography (CT) is capable of quantifying fat, based on decreased attenuation with increased fat concentration. Current quantitative fat phantoms do not accurately mimic the CT number of human liver. The purpose of this work was to develop and validate an optimized phantom that simultaneously mimics the MRI and CT signals of fatty liver.

Methods

An agar‐based phantom containing 12 vials doped with iodinated contrast, and with a granular range of fat fractions was designed and constructed within a novel CT and MR compatible spherical housing design. A four‐site, three‐vendor validation study was performed. MRI (1.5T and 3T) and CT images were obtained using each vendor's PDFF and CT reconstruction, respectively. An ROI centered in each vial was placed to measure MRI‐PDFF (%) and CT number (HU). Mixed‐effects model, linear regression, and Bland‐Altman analysis were used for statistical analysis.

Results

MRI‐PDFF agreed closely with nominal PDFF values across both field strengths and all MRI vendors. A linear relationship (slope = −0.54 ± 0.01%/HU, intercept = 37.15 ± 0.03%) with an R2 of 0.999 was observed between MRI‐PDFF and CT number, replicating established in vivo signal behavior. Excellent test‐retest repeatability across vendors (MRI: mean = −0.04%, 95% limits of agreement = [−0.24%, 0.16%]; CT: mean = 0.16 HU, 95% limits of agreement = [−0.15HU, 0.47HU]) and good reproducibility using GE scanners (MRI: mean = −0.21%, 95% limits of agreement = [−1.47%, 1.06%]; CT: mean = −0.18HU, 95% limits of agreement = [−1.96HU, 1.6HU]) were demonstrated.

Conclusions

The proposed fat phantom successfully mimicked quantitative liver signal for both MRI and CT. The proposed fat phantom in this study may facilitate broader application and harmonization of liver fat quantification techniques using MRI and CT across institutions, vendors and imaging platforms.
An examination of gastrointestinal absorption using the acetaminophen absorption test in critically ill patients with COVID‐19: A retrospective cohort study
Authors: Southren Daniel L. , Nardone Alexa D. , Haastrup Adeniran A. , Roberts Russel J. , Chang Marvin G. , Bittner Edward A.
Published: June 2021

Objective

Gastrointestinal (GI) dysfunction is prevalent in critically ill patients with coronavirus disease 2019 (COVID‐19). The acetaminophen absorption test (AAT) has been previously described as a direct method for assessment of GI function. Our study determines whether the AAT can be used to assess GI function in critically ill COVID‐19 patients, compared with traditional measures of GI function.

Design

Retrospective observational study of critically ill patients with COVID‐19.

Setting

Three intensive care units at a tertiary care academic medical center.

Patients

Twenty critically ill patients with COVID‐19.

Interventions

The results of AAT and traditional measures for assessing GI function were collected and compared.

Measurements and Main Results

Among the study cohort, 55% (11 of 20) of patients had evidence of malabsorption by AAT. Interestingly, all patients with evidence of malabsorption by AAT had clinical evidence of bowel function, as indicated by stool output and low gastric residuals during the prior 24 h. When comparing patients with a detectable acetaminophen level (positive AAT) with those who had undetectable acetaminophen levels (negative AAT), radiologic evidence of ileus was less frequent (20 vs 88%; P = .03), tolerated tube‐feed rates were higher (40 vs 10 ml/h; P =.01), and there was a trend toward lower gastric residual volumes (45 vs 830 ml; P =.11).

Conclusion

Malabsorption can occur in critically ill patients with COVID‐19 despite commonly used clinical indicators of tube‐feeding tolerance. The AAT provides a simple, rapid, and cost‐effective mechanism by which enteral function can be efficiently assessed in COVID‐19 patients.
Fault estimation and fault tolerance control for spacecraft formation systems with actuator fault and saturation
Authors: Gao Zhifeng , Wang Sen
Published: June 2021

In this study, a novel fault estimation and fault tolerant control (FTC) scheme is proposed for a class of nonlinear spacecraft formation flying systems in actuator fault and saturation case, in which the directed communication topology with leader spacecraft as the root. The decentralized unknown input observer is designed to estimate the unknown actuator fault factors, which affect the performance of spacecraft formation flying systems. The obtained fault estimated values are served as the design of distributed fault tolerant formation controller. Then, a distributed fault tolerant formation control algorithm is proposed using adaptive terminal sliding mode control (ATSMC) technique, such that each follower spacecraft could synchronize with leader spacecraft in the presence of actuator fault and saturation case. Finally, the effectiveness of the proposed FTC scheme is verified by numerical practical examples.
Work from home—Work engagement amid COVID‐19 lockdown and employee happiness
Authors: Mehta Prashant
Published: June 2021

Prolonged lockdown as a part of the community mitigation steps to control the spread of the corona virus has led to massive work reorganization throughout the world. Companies as well as individuals are attempting to adjust to this new world of work. Organizations have shifted substantial parts of their work for certain sets of jobs to a “work from home (WFH)” format. The aim of this study is to investigate the relationship between WFH) work engagement and perceived employee happiness. WFH work engagement was hypothesized to be influenced by WFH autonomy, WFH convenience, and WFH psychosocial safety. All of the constructs were adapted from established scales. Convenience sampling was used for data collection as, under the circumstances, this was the only viable method. Partial least squares structural equation modelling was used for data analysis. Results from this study indicate that WFH work engagement was able to predict a 23.9% variance in perceived happiness, while exogenous constructs, such as WFH autonomy, WFH convenience, and WFH psychosocial safety, were able to predict a 25.2% variance in WFH work engagement. Further f2 effect size (0.313) between WFH work engagement and happiness indicates high effect size. In order to assess the predictive relevance of the model, a blindfolding procedure was used to obtain Q2 values. Q2 values greater than zero indicate that the model has predictive relevance.
Capturing South Africa's developmental state: State‐society relations and responses to state capture
Authors: Khambule Isaac
Published: June 2021

Under the leadership of the governing African National Congress, the South African government has long touted the idea of becoming a developmental state as the country's ultimate response to rising unemployment, poverty and inequality. This idea aligns with the rapid economic growth and industrialization experienced by the East Asian developmental states through directing the state's administrative capacities, resources and policies towards attaining national developmental goals. Similarly, the National Development Plan pins South Africa's developmental state ambition on creating a capable developmental state and the formation of dynamic institutions capable of utilizing the state's administrative powers, resources and policies to pursue developmental goals. However, the country's state institutions, administrative capacities and resources have been challenged by the state capture debacle that shed light on the corrupt relationship between the political elite and the business elite. This article explores civil society's response to state capture and analyzes the impact of civil society's responses on South Africa's developmental state ambition. The article reveals that the state‐society relations had a significant effect on fighting the state‐business corrupt arrangement by mobilizing nationwide protests that solidified South Africa's emerging democratic developmental state framework embedded in state‐society relations.
Risk of clinically relevant hyperglycemia with metoprolol compared to carvedilol in older adults with heart failure and diabetes
Authors: Dave Chintan V. , Strom Brian L. , Kobylarz Fred A. , Horton Daniel B. , Gerhard Tobias , Tseng Chin‐Lin , Dejanovic Ilja , Nyandege Abner , Setoguchi Soko
Published: June 2021

Background

Although prior literature suggests that metoprolol may worsen glucose control compared to carvedilol, whether this has clinical relevance among older adults with diabetes and heart failure (HF) remains an open question.

Methods

This was a US retrospective cohort study utilizing data sourced from a 50% national sample of Medicare fee‐for‐service claims of patients with part D prescription drug coverage (2007–2017). Among patients with diabetes and HF, we identified initiators of metoprolol or carvedilol, which were 1:1 propensity score matched on >90 variables. The primary outcome was initiation of a new oral or injectable antidiabetic medication (proxy for uncontrolled diabetes); secondary outcomes included initiation of insulin and severe hyperglycemic event (composite of emergency room visits or hospitalizations related to hyperglycemia).

Results

Among 24 239 propensity score–matched pairs (mean [SD] age 77.7 [8.0] years; male [39.1%]), there were 8150 (incidence rate per 100 person‐years [IR] = 33.5) episodes of antidiabetic medication initiation among metoprolol users (exposure arm) compared to 8576 (IR = 33.4) among carvedilol users (comparator arm) compared to corresponding to an adjusted hazard ratio (aHR) of 0.97 (95% confidence interval [CI]: 0.94, 1.01). Similarly, metoprolol was not associated with a significant increase in the risk of secondary outcomes including insulin initiation: aHR of 0.98 (95% CI: 0.93, 1.04) and severe hyperglycemic events: aHR of 0.98 (95% CI: 0.93, 1.02).

Conclusions

In this large study of older adults with HF and diabetes, initiation of metoprolol compared to carvedilol was not associated with an increase in the risk of clinically relevant hyperglycemia.
The role of interpretation biases and symptom burden in fear of cancer recurrence/progression among ovarian cancer survivors
Authors: Pradhan Poorva , Sharpe Louise , Butow Phyllis , Russell Hayley
Published: June 2021

Background

Models of fear of cancer recurrence or progression (FCR/P) suggest that the way in which people interpret ambiguous physical symptoms is an important contributor to the development and maintenance of FCR/P, but research has not investigated this claim. The aim of this study is to fill that gap.

Methods

This was a cross‐sectional study. Sixty‐two women with ovarian cancer reported completed measures of FCR/P, an interpretation bias task and a symptom checklist. The healthy control group (n = 96) completed the interpretation bias task.

Results

Women with ovarian cancer were more likely to interpret ambiguous words as health‐related compared to healthy women (p < 0.001; Cohen's d = 1.28). In women with cancer, FCR/P was associated with overall symptom burden (r = 0.25; p = 0.04) and interpretation bias score (r = 0.41; p = 0.001), but interpretation bias and symptom burden were not related (r = 0.22; p = 0.09). Interpretation bias did not moderate the relationship between symptoms and FCR/P.

Conclusions

We found that women with ovarian cancer interpreted ambiguous words as health related more often compared to women without cancer, and this bias was greater for women with higher FCR/P. Symptom burden was also associated with FCR/P. However, interpretation bias did not moderate the relationship between physical symptoms and FCR/P. Hence, the central tenet of the Cancer Threat Interpretation model was not supported in women with ovarian cancer.
Nicking and fragmentation are responsible for α‐lactalbumin amyloid fibril formation at acidic pH and elevated temperature
Authors: Rahamtullah  , Mishra Rajesh
Published: June 2021

Amyloid fibrils are ordered aggregates that may be formed from disordered, partially unfolded, and fragments of proteins and peptides. There are several diseases, which are due to the formation and deposition of insoluble β‐sheet protein aggregates in various tissue, collectively known as amyloidosis. Here, we have used bovine α‐lactalbumin as a model protein to understand the mechanism of amyloid fibril formation at pH 1.6 and 65°C under non‐reducing conditions. Amyloid fibril formation is confirmed by Thioflavin T fluorescence and atomic force microscopy (AFM). Our finding demonstrates that hydrolysis of peptide bonds occurs under these conditions, which results in nicking and fragmentation. The nicking and fragmentation have been confirmed on non‐reducing and reducing gel. We have identified the fragments by matrix‐assisted laser desorption ionization‐time of flight (MALDI‐TOF) mass spectrometry. The fragmentation may initiate nucleation as it coincides with AFM images. Conformational changes associated with monomer resulting in fibrillation are shown by circular dichroism and Raman spectroscopy. The current study highlights the importance of nicking and fragmentation in amyloid fibril formation, which may help understand the role of acidic pH and proteolysis under in vivo conditions in the initiation of amyloid fibril formation.
A hybrid method based on P and P′ control chart for identifying hotspots
Authors: Jahan Ali , Abbaspour Afshin , Safakhah Soroush
Published: June 2021

The terms “hotspots,” “blackspot,” or “high‐risk” are normally used for an area on a road where the number of car accidents are far beyond the normal level and, more importantly, the causes of the incident always link to one or many specific reasons. Identifying these spots is helpful and may assist people in authority to implement corrective actions. To do the aforementioned, some decision‐support tools could be useful since they enable us to monitor the indicators that may lead to a car accident, same as the procedure engineers use to control production lines in factories. In this regard, control charts are utilized to identify blackspots. Although the method is low cost, and provides quick detection and statistical reliability level and, more importantly, uses online applications; however, it advised that the rate quality control method could be used on roads with the same geometry and traffic conditions. This research develops a hybrid method, based on accident type, for improving rate quality control method to overcome the shortcomings. Furthermore, the suggested framework considers crash severity and traffic volume that have not been taken into account in the rate quality control method yet. The case study evaluates how this framework is successful to identify blackspots, and based on the result in the real environment, it reveals that the proposed method could detect and identify the hotspots.
Ultra‐fast retroactive processing by MetAlign of liquid chromatography/high‐resolution full‐scan Orbitrap mass spectrometry data in WADA Human Urine Sample Monitoring Program
Authors: Khelifi Safa , Saad Khadija , Vonaparti Ariadni , Mahieddine Souhila , Salama Sofia , Saleh Amal , Al‐Mohannadi Maryam , Al‐Thaiban Hussain , Lommen Arjen , Horvatovich Peter , Beotra Alka , Abushareeda Wadha , Al Maadheed Mohammed , Georgakopoulos Costas
Published: June 2021

Rationale

The World Antidoping Agency (WADA) Monitoring program concentrates analytical data from the WADA Accredited Laboratories for substances which are not prohibited but whose potential misuse must be known. The WADA List of Monitoring substances is updated annually, where substances may be removed, introduced or transferred to the Prohibited List, depending on the prevalence of their use. Retroactive processing of old sample datafiles has the potential to create information for the prevalence of use of candidate substances for the Monitoring List in previous years. MetAlign is a freeware software with functionality to reduce the size of liquid chromatography (LC)/high‐resolution (HR) full‐scan (FS) mass spectrometry (MS) datafiles and to perform a fast search for the presence of substances in thousands of reduced datafiles.

Methods

Validation was performed to the search procedure of MetAlign applied to Anti‐Doping Lab Qatar (ADLQ)‐screened LC/HR‐FS‐MS reduced datafiles originated from antidoping samples for tramadol (TRA), ecdysterone (ECDY) and the ECDY metabolite 14‐desoxyecdysterone (DESECDY) of the WADA Monitoring List. Searching parameters were related to combinations of accurate masses and retention times (RTs).

Results

MetAlign search validation criteria were based on the creation of correct identifications, false positives (FPs) and false negatives (FNs). The search for TRA in 7410 ADLQ routine LC/HR‐FS‐MS datafiles from the years 2017 to 2020 revealed no false identification (FPs and FNs) compared with the ADLQ WADA reports. ECDY and DESECDY were detected by MetAlign search in approximately 5% of the same cohort of antidoping samples.

Conclusions

MetAlign is a powerful tool for the fast retroactive processing of old reduced datafiles collected in screening by LC/HR‐FS‐MS to reveal the prevalence of use of antidoping substances. The current study proposed the validation scheme of the MetAlign search procedure, to be implemented per individual substance in the WADA Monitoring program, for the elimination of FNs and FPs.
Phytoremediation of Arsenic in Mine Wastes by Acacia mangium
Authors: Rosli Ruhan A. , Harumain Zakuan A. S. , Zulkalam Muhammad F. , Hamid Azzmer A. A. , Sharif Mohd F. , Mohamad Mohd A. N. , Noh Abdul L. , Shahari Rozilawati
Published: June 2021

This study explored the potential of Acacia mangium to remediate arsenic present in mine wastes and to determine the remediation mechanism of this plant for removing arsenic. A preliminary test using soil spiked with various arsenic concentrations showed that Acacia mangium was able to survive on arsenic‐contaminated soil with concentrations up to 500 mg kg−1 arsenic. Ex situ phytoremediation studies using mine wastes containing approximately 790 mg kg−1 arsenic also showed no toxicity effect on Acacia mangium throughout 5 months of treatment. Bioconcentration and translocation factors indicate that Acacia mangium utilizes phytostabilization as its main mechanism to uptake arsenic into the plant tissues. The use of the chemical lixiviants monoammonium phosphate and citric acid was also found to increase the translocation of arsenic from roots to stems of Acacia mangium with a 12‐ and six‐fold increase, respectively, compared with the un‐dosed plants. Further speciation analysis revealed that arsenic in the form of arsenate was the only arsenic species detected in the stems after being amended with monoammonium phosphate; thereby, suggesting a sensible strategy for more efficient targeted arsenic phytoremediation by Acacia mangium.
A fast and efficient Modal EM algorithm for Gaussian mixtures
Authors: Scrucca Luca
Published: June 2021

In the modal approach to clustering, clusters are defined as the local maxima of the underlying probability density function, where the latter can be estimated either nonparametrically or using finite mixture models. Thus, clusters are closely related to certain regions around the density modes, and every cluster corresponds to a bump of the density. The Modal Expectation‐Maximization (MEM) algorithm is an iterative procedure that can identify the local maxima of any density function. In this contribution, we propose a fast and efficient MEM algorithm to be used when the density function is estimated through a finite mixture of Gaussian distributions with parsimonious component‐covariance structures. After describing the procedure, we apply the proposed MEM algorithm on both simulated and real data examples, showing its high flexibility in several contexts.
UV Photochromism in Transition Metal Oxides and Hybrid Materials
Authors: Kayani Aminuddin Bin Ahmad , Kuriakose Sruthi , Monshipouri Mahta , Khalid Fararishah Abdul , Walia Sumeet , Sriram Sharath , Bhaskaran Madhu
Published: June 2021

Limited levels of UV exposure can be beneficial to the human body. However, the UV radiation present in the atmosphere can be damaging if levels of exposure exceed safe limits which depend on the individual the skin color. Hence, UV photochromic materials that respond to UV light by changing their color are powerful tools to sense radiation safety limits. Photochromic materials comprise either organic materials, inorganic transition metal oxides, or a hybrid combination of both. The photochromic behavior largely relies on charge transfer mechanisms and electronic band structures. These factors can be influenced by the structure and morphology, fabrication, composition, hybridization, and preparation of the photochromic materials, among others. Significant challenges are involved in realizing rapid photochromic change, which is repeatable, reversible with low fatigue, and behaving according to the desired application requirements. These challenges also relate to finding the right synergy between the photochromic materials used, the environment it is being used for, and the objectives that need to be achieved. In this review, the principles and applications of photochromic processes for transition metal oxides and hybrid materials, photocatalytic applications, and the outlook in the context of commercialized sensors in this field are presented.
Phase segregation mechanisms of small molecule‐polymer blends unraveled by varying polymer chain architecture
Authors: Chen Jihua , Das Sanjib , Shao Ming , Li Guoliang , Lian Huada , Qin Jian , Browning James F. , Keum Jong K. , Uhrig David , Gu Gong , Xiao Kai
Published: June 2021

As phase separation between the small‐molecule semiconductor and the polymer binder is the key enabler of blend‐based organic field‐effect transistors (OFETs) fabricated by low‐cost solution processing, it is crucial to understand the underlying phase separation mechanisms that determine the phase morphology, which significantly impacts device performance. Beyond the parameter space investigated in previous work, here we investigate the formation of blends by varying the branch architecture of the polymer binder and by shortening the solvent dry time using ultrasonic spray casting. The phase morphologies of the resulting blend films have been thoroughly characterized with a variety of techniques in three dimensions over multiple length scales, including AFM, energy‐filtered transmission electron microscope, and neutron reflectivity, and have been correlated with electrical transport performance. From the results, we have inferred that the phase morphology is kinetically determined, limited by the inherent slow movement of polymer macromolecules. The kinetic picture, supported by molecular dynamics modeling, not only consistently explains our observations but also resolves inconsistencies in previous works. The achieved mechanistic understanding will guide further optimization of blend‐based organic electronics, such as OFETs and organic photovoltaics.
Finance sustainable supply chain: An analysis looking for B corporations and agency theory
Authors: de Morais Carlos Eduardo , Paschoiotto Waldemir Paulino , Bernardes Leandro dos Santos , Sehnem Simone , Salgueirinho de Andrade Guerra José Baltazar
Published: June 2021

Companies are often seen as villains since their main purpose is to generate shareholder value. A deeper view of organizations, however, reveals that companies have a more comprehensive role than just achieving economic returns. Based on this premise, this study aims to analyze the financing of supply chains of B corporations; we employ the perspective of agency theory in the context of the “new emerging normal.” A multiple case study of companies belonging to the B corporations’ ranking in the Brazilian scenario was prepared. In‐depth interviews were conducted with key informants from the investigated companies. The results show that the cost of obtaining certification is borne by the companies’ own resources, which are motivated by pressure from the environmental demands. The main conclusion of the study is that B Corporations, driven by economic perspectives, tend to assume the role of drivers of supply chain development. The main contribution, therefore, consists of demonstrating, based on the agency theory and the finance supply chain, that the performance of an organization under the bias of sustainability creates a collaborative cycle that induces the development of its entire supply chain.
Influence of transaction costs on smallholder poultry market participation in Nigeria: A mixed‐methods analysis
Authors: Antia‐Obong Essien A. , Hubbard Carmen , Garrod Guy
Published: June 2021

Key to doing business involves lowering transaction costs which incorporates both tangible and intangible costs. Investigations traditionally apply quantitative analysis. Consequently, intangible costs perceived to influence smallholder market participation decisions have been left unobserved. The study therefore investigates how and why transaction costs influence smallholder poultry market participation using explanatory sequential mixed‐methods design for the first time. Cragg's double‐hurdle model is used for the quantitative analysis. Findings show that probability of market participation is influenced by access to veterinary services (VET), access to alternative sources of farm cash, longer distance to market, and shorter distance to tarred roads. Extent of market participation is influenced by access to informal information sources and inaccessibility of non‐farm income. Qualitative analysis identified three themes “Accessibility,” “Availability,” and “Adequacy” of transaction costs in influencing the decision and level of market participation. The findings indicate the need for continuous rural infrastructure development in the areas of roads and transport. Furthermore, to ease access to market information, institutionalized market information services need to be prioritized. In addition, improved access to VET for farmers needs to be strengthened. Importantly, agricultural interventions should account for employment status to enhance extent of market participation.
Axisymmetric hybrid nanofluid flow with heat and mass transfer amongst the two gyrating plates
Authors: Bilal Muhammad , Gul Taza , Alsubie Abdelaziz , Ali Ishtiaq
Published: June 2021

The combined effects of magnetic and electrohydrodynamic on the water‐based iron oxide and CNTs hybrid nanoliquids flow between two rotating plates are examined. The influence of electro‐magneto‐hydrodynamics on the mass and heat transmission characteristics is the main aim of this study. The hybrid nanofluid is synthesized using water as a base fluid in the (Iron oxide) , single and multi‐walled (SWCNTs/MWCNTs) carbon nanotubes (CNTs). The flow model has been arranged in form of PDEs, which are reduced into the system of dimensionless differential equations through a similarity approach. The differential equations are further treated with HAM to get analytic results. The impact of the Reynolds number, magnetic, electric and rotation parameters, on the drag force, mass flux and heat transmission rate has been scrutinized and discussed. The arithmetic consequences are carried out for Nusselt number, Sherwood number and drag force. The heat transmission has been considered to increase with the Reynolds number, magnetic constraint and electric parameter. The electric parameter improving the momentum boundary layer and drop the thermal boundary layer. The outcomes are compared with the existing literature and a closed agreement has found.
Evolution of the Agile Scaling Frameworks
Authors: Uludağ Ömer , Putta Abheeshta , Paasivaara Maria , Matthes Florian
Published: June 2021

Over the past decade, agile methods have become the favored choice for projects undertaken in rapidly changing environments. The success of agile methods in small, co-located projects has inspired companies to apply them in larger projects. Agile scaling frameworks, such as Large Scale Scrum and Scaled Agile Framework, have been invented by practitioners to scale agile to large projects and organizations. Given the importance of agile scaling frameworks, research on those frameworks is still limited. This paper presents our findings from an empirical survey answered by the methodologists of 15 agile scaling frameworks. We explored (i) framework evolution, (ii) main reasons behind their creation, (iii) benefits, and (iv) challenges of adopting these frameworks. The most common reasons behind creating the frameworks were improving the organization’s agility and collaboration between agile teams. The most commonly claimed benefits included enabling frequent deliveries and enhancing employee satisfaction, motivation, and engagement. The most mentioned challenges were using frameworks as cooking recipes instead of focusing on changing people’s culture and mindset.
S-folds and holographic RG flows on the D3-brane
Authors: Guarino Adolfo , Sterckx Colin
Published: June 2021

Abstract

Type IIB S-folds of the form AdS4 × S1 × S5 are conjectured to correspond to new strongly coupled three-dimensional CFT’s on a localised interface of SYM4. In this work we construct holographic RG flows on the D3-brane that generically connect anisotropic deformations of SYM4 in the UV to various S-fold CFT’s in the IR with different amounts of supersymmetry and flavour symmetries. Examples of holographic RG flows between S-fold CFT’s are also presented. Lastly a geometric interpretation of axion deformations is provided in terms of monodromies on the internal S5 when moving around the S1. Special attention is paid to the monodromy-induced patterns of symmetry breaking as classified by the mapping torus Th(S5).
Places of Near-Fields: To Heinrich Wefelscheid
Authors: Karpfinger Christian
Published: June 2021

Wefelscheid (Untersuchungen über Fastkörper und Fastbereiche, Habilitationsschrift, Hamburg, 1971) generalised the well-known Theorem of Artin/Schreier about the characterization of formally real fields and the fundamental result of Baer/Krull to near-fields. In the last fifty years arose from the Theorem of Baer/Krull a theory, which analyses the entirety of the orderings of a field (E. Becker, L. Bröcker, M. Marshall et al.), as presented e.g. in the book by Lam (Orderings, valuations and quadratic forms, American Mathematical Society, Providence, 1983). At the centre of this theory are preorders and their compatibility with valuations or places. We develop some essential results of this theory for the near-field case. In particular, we derive the Brown/Marshall’s inequalities and Bröcker’s Theorem on the trivialisation of fans in the near-field case.
Experimental investigations of spontaneous damage to wet multi-plate clutches with carbon friction linings
Authors: Groetsch D. , Stockinger U. , Schneider T. , Reiner F. , Voelkel K. , Pflaum H. , Stahl K.
Published: June 2021

Safety and comfort, while ensuring torque transfer capability, are essential for wet multi-plate clutches. The safety of the torque transmission process largely depends on the endurance of the tribological system against spontaneous and long-term damages. Modern Carbon friction linings in wet multi-plate clutch applications offer superior wear resistance compared to other friction materials, but there is hardly any published data on their spontaneous damage behavior. This article therefore presents results from experimental studies on the spontaneous damage of innovative Carbon friction linings carried out on a component test rig. Furthermore, the influence of different steel plate thicknesses (3.5 mm vs. 6 mm) was investigated. 16 step tests, including visual assessments of the clutches, were performed with Carbon-fiber reinforced plastic (CFRP) and Carbon-fiber reinforced Carbon (C/C) linings in brake operations.

The results of the step tests are documented in friction work over friction power diagrams. Results show excellent endurance of modern Carbon friction linings against spontaneous damage and thus makes them suitable for safety relevant high-performance applications. There was no clear influence of the steel plate thickness on spontaneous damage. However, the C/C friction lining ran at a specific energy of up to 5.26 J/mm2 in combination with sliding velocities of up to 67 m/s (high speed application) without failure. This is the highest published spontaneous damage resistance identified for wet clutches.
On systematically building a controlled natural language for functional requirements
Authors: Veizaga Alvaro , Alferez Mauricio , Torre Damiano , Sabetzadeh Mehrdad , Briand Lionel
Published: June 2021

Natural language (NL) is pervasive in software requirements specifications (SRSs). However, despite its popularity and widespread use, NL is highly prone to quality issues such as vagueness, ambiguity, and incompleteness. Controlled natural languages (CNLs) have been proposed as a way to prevent quality problems in requirements documents, while maintaining the flexibility to write and communicate requirements in an intuitive and universally understood manner. In collaboration with an industrial partner from the financial domain, we systematically develop and evaluate a CNL, named Rimay, intended at helping analysts write functional requirements. We rely on Grounded Theory for building Rimay and follow well-known guidelines for conducting and reporting industrial case study research. Our main contributions are: (1) a qualitative methodology to systematically define a CNL for functional requirements; this methodology is intended to be general for use across information-system domains, (2) a CNL grammar to represent functional requirements; this grammar is derived from our experience in the financial domain, but should be applicable, possibly with adaptations, to other information-system domains, and (3) an empirical evaluation of our CNL (Rimay) through an industrial case study. Our contributions draw on 15 representative SRSs, collectively containing 3215 NL requirements statements from the financial domain. Our evaluation shows that Rimay is expressive enough to capture, on average, 88% (405 out of 460) of the NL requirements statements in four previously unseen SRSs from the financial domain.
Reliability of self-rated experience and confidence as predictors for students’ performance in software engineering
Authors: Daun Marian , Brings Jennifer , Obe Patricia Aluko , Stenkova Viktoria
Published: June 2021

Students’ experience is used in empirical software engineering research as well as in software engineering education to group students in either homogeneous or heterogeneous groups. To do so, students are commonly asked to self-rate their experience, as self-rated experience has been shown to be a good predictor for performance in programming tasks. Another experience-related measurement is participants’ confidence (i.e., how confident is the person that their given answer is correct). Hence, self-rated experience and confidence are used as selector or control variables throughout empirical software engineering research and software engineering education. In this paper, we analyze data from several student experiments conducted in the past years to investigate whether self-rated experience and confidence are also good predictors for students’ performance in model comprehension tasks. Our results show that while students can somewhat assess the correctness of a particular answer to one concrete question regarding a conceptual model (i.e., their confidence), their overall self-rated experience does not correlate with their actual performance. Hence, the use of the commonly used measurement of self-rated experience as a selector or control variable must be considered unreliable for model comprehension tasks.
Pay-to-Win Gaming and its Interrelation with Gambling: Findings from a Representative Population Sample
Authors: Steinmetz Fred , Fiedler Ingo , von Meduna Marc , Ante Lennart
Published: June 2021

Pay-to-Win gaming describes a common type of video game design in which players can pay to advance in the game. The frequency and value of payments is unlimited, and payments are linked to players’ competitiveness or progress in the game, which can potentially facilitate problematic behavioral patterns, similar to those known from gambling. Our analyses focus on assessing similarities and differences between Pay-to-Win and different forms of gambling. Based on a survey among 46,136 German adult internet users, this study presents the demographic and socio-economic profile of (1) Pay-to-Win gamers who make purchases in such games, (2) heavy users who conduct daily payments, and (3) gamers who are also gamblers. Motives for making payments were assessed and participation, frequency and spending in gambling by Pay-to-Win gamers are presented. To assess the similarity of Pay-to-Win gaming and gambling, we tested whether Pay-to-Win participation, frequency of payments and problematic gaming behavior are predictors for gambling and cross-tested the opposite effects of gambling on Pay-to-Win. We find that Pay-to-Win gamers are a distinct consumer group with considerable attraction to gambling. High engagement and problematic behavior in one game form affects (over)involvement in the other. Common ground for Pay-to-Win gaming and gambling is the facilitation of recurring payments.
Phenomenological and existential contributions to the study of erectile dysfunction
Authors: Suijker Chris A. , van Mazijk Corijn , Keijzer Fred A. , Meijer Boaz
Published: June 2021

The current medical approach to erectile dysfunction (ED) consists of physiological, psychological and social components. This paper proposes an additional framework for thinking about ED based on phenomenology, by focusing on the theory of sexual projection. This framework will be complementary to the current medical approach to ED. Our phenomenological analysis of ED provides philosophical depth and illuminates overlooked aspects in the study of ED. Mainly by appealing to Merleau-Ponty’s Phenomenology of Perception, we suggest considering an additional etiology of ED in terms of a weakening of a function of sexual projection. We argue that sexual projection can be problematized through cognitive interferences, changes in the ‘intentional arc’, and modifications in the subject’s ‘body schema’. Our approach further highlights the importance of considering the ‘existential situation’ of patients with ED. We close by reflecting briefly on some of the implications of this phenomenological framework for diagnosis and treatment of ED.
Optimal solutions of multiplier DEA models
Authors: Podinovski Victor V. , Bouzdine-Chameeva Tatiana
Published: June 2021

Conventional models of data envelopment analysis (DEA) are based on the constant and variable returns-to-scale production technologies. Any optimal input and output weights of the multiplier DEA models based on these technologies are interpreted as being the most favorable for the decision making unit (DMU) under the assessment when the latter is benchmarked against the set of all observed DMUs. In this paper we consider a very large class of DEA models based on arbitrary polyhedral technologies, which includes almost all known convex DEA models. We highlight the fact that the conventional interpretation of the optimal input and output weights in such models is generally incorrect, which raises a question about the meaning of multiplier models. We address this question and prove that the optimal solutions of such models show the DMU under the assessment in the best light in comparison to the entire technology, but not necessarily in comparison to the set of observed DMUs. This result allows a clear and meaningful interpretation of the optimal solutions of multiplier models, including known models with a complex constraint structure whose interpretation has been problematic and left unaddressed in the existing literature.
On completely factoring any integer efficiently in a single run of an order-finding algorithm
Authors: Ekerå Martin
Published: June 2021

We show that given the order of a single element selected uniformly at random from $${\mathbb {Z}}_N^*$$

Z
N
∗

, we can with very high probability, and for any integer N, efficiently find the complete factorization of N in polynomial time. This implies that a single run of the quantum part of Shor’s factoring algorithm is usually sufficient. All prime factors of N can then be recovered with negligible computational cost in a classical post-processing step. The classical algorithm required for this step is essentially due to Miller.
Innovations and new possibilities of vehicle tracking in transport and forwarding
Authors: Huk Katarzyna , Kurowski Mateusz
Published: June 2021

Changes taking place on the market set new development trends and create new threats which enterprises must face. If management does not take up the challenge, the company's development may slow down and fail to cope with the growing competition. That is why it is so important to flexibly adapt to changing economic conditions and implement innovations. New solutions and improvements can be observed in every area of the company's activity, in particular industries and sectors of the economy. Keeping up with new trends and implementing innovations is now a determinant of achieving a competitive advantage. New solutions and opportunities also apply to the TSL industry (transport, forwarding, logistics). New innovations and opportunities arise constantly in different areas of this field. The subject of interest of this article is the development and innovation in the field of road transport and IT systems implemented in enterprises. The study was prepared on the basis of the literature review and own study based on transport, forwarding and the group representing other sectors of economy. The aim of the study is to identification innovations and new possibilities in the field of telematics systems used to identify transportation units in motion.
k-Provability in $$\hbox {PA}$$
Authors: Santos Paulo Guilherme , Kahle Reinhard
Published: June 2021

We study the decidability ofk-provability in$$\hbox {PA}$$PA—the relation ‘being provable in$$\hbox {PA}$$PAwith at mostksteps’—and the decidability of the proof-skeleton problem—the problem of deciding if a given formula has a proof that has a given skeleton (the list of axioms and rules that were used). The decidability ofk-provability for the usual Hilbert-style formalisation of$$\hbox {PA}$$PAis still an open problem, but it is known that the proof-skeleton problem is undecidable for that theory. Using new methods, we present a characterisation of some numberskfor whichk-provability is decidable, and we present a characterisation of some proof-skeletons for which one can decide whether a formula has a proof whose skeleton is the considered one. These characterisations are natural and parameterised by unification algorithms.
Effectiveness and petroleum geological significance of tectonic fractures in the ultra-deep zone of the Kuqa foreland thrust belt: a case study of the Cretaceous Bashijiqike Formation in the Keshen gas field
Authors: Zhang Rong-Hu , Wang Ke , Zeng Qing-Lu , Yu Chao-Feng , Wang Jun-Peng
Published: June 2021

The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m. The average matrix porosity of the reservoir is 5.5%, and the average matrix permeability is 0.128 × 10−3 μm2. In order to reveal the characteristics and effectiveness of ultra-deep fractures and their effects on reservoir properties and natural gas production, outcrops, cores, thin section, image logs and production testing data are used to investigate the effectiveness of tectonic fractures in ultra-deep reservoirs in the Kuqa foreland thrust zone, and the corresponding geological significance for oil and gas exploration and development are discussed. Tectonic fractures in the thrust belt include EW-trending high-angle tensile fractures and NS-trending vertical shear fractures. The former has a relatively high filling rate, while the latter is mostly unfilled. Micro-fractures are usually grain-piercing-through cracks with width of 10–100 microns. In the planar view, the effective fractures are concentrated in the high part and wing zones of the long axis of the anticline, and along the vertical direction, they are mainly found in the tensile fracture zone above the neutral plane. The adjustment fracture zone has the strongest vertical extension abilities and high effectiveness, followed by the nearly EW longitudinal tensile fracture zone, and the netted fracture zone with multiple dip angles. The effectiveness of fracture is mainly controlled by fracture aperture and filling degrees. Effective fractures can increase reservoir permeability by 1–2 orders of magnitude. The higher part of the anticline is associated with high tectonic fracture permeability, which control enrichment and high production of natural gas. The netted vertical open fractures effectively communicate with pores and throats of the reservoir matrix, which forms an apparent-homogenous to medium-heterogeneous body that is seen with high production of natural gas sustained for a long term.