bluuebunny/crossref_metadata_2025 huggingface dataset:
Dolos: Language‐agnostic plagiarism detection in source code
Authors: Maertens Rien , Van Petegem Charlotte , Strijbol Niko , Baeyens Toon , Jacobs Arne Carla , Dawyndt Peter , Mesuere Bart
Published: March 2022

Background

Learning to code is increasingly embedded in secondary and higher education curricula, where solving programming exercises plays an important role in the learning process and in formative and summative assessment. Unfortunately, students admit that copying code from each other is a common practice and teachers indicate they rarely use plagiarism detection tools.

Objectives

We want to lower the barrier for teachers to detect plagiarism by introducing a new source code plagiarism detection tool (Dolos) that is powered by state‐of‐the art similarity detection algorithms, offers interactive visualizations, and uses generic parser models to support a broad range of programming languages.

Methods

Dolos is compared with state‐of‐the‐art plagiarism detection tools in a benchmark based on a standardized dataset. We describe our experience with integrating Dolos in a programming course with a strong focus on online learning and the impact of transitioning to remote assessment during the COVID‐19 pandemic.

Results and Conclusions

Dolos outperforms other plagiarism detection tools in detecting potential cases of plagiarism and is a valuable tool for preventing and detecting plagiarism in online learning environments. It is available under the permissive MIT open‐source license at https://dolos.ugent.be.

Implications

Dolos lowers barriers for teachers to discover, prove and prevent plagiarism in programming courses. This helps to enable a shift towards open and online learning and assessment environments, and opens up interesting avenues for more effective learning and better assessment.
Commentary: Are complex parenting interventions less than the sum of their parts? A reflection on Leijten et al. (2022)
Authors: Fearon Pasco , Sonuga‐Barke Edmund
Published: March 2022

Parenting interventions provide the backbone of professional support for children with behavioural problems and their families (Maughan et al., 2005). The overwhelming evidence for their value, at least in the short term, has prompted the field to move away from simply testing their efficacy to focus on issues of implementation. More and more studies are therefore addressing the interrelated goals of optimising outcomes, increasing scalability and affordability, improving access and removing barriers for hard‐to‐reach and treat families (e.g., Barnett et al., 2019; Day et al., 2012; Kazdin, 2015). Because parenting interventions are often complex and integrate multiple discrete therapeutic elements, achieving cost‐effective interventions that can be implemented efficiently at scale will depend on identifying which elements work best and which are redundant and can be cut. This can help streamline interventions to make them less burdensome by cutting the time, effort and resources needed for families to take part and making the interventions themselves easier to train and deliver. It can also help focus energies on areas where improvements of existing interventions are most needed and/or likely to yield the most value. Leijten and colleagues (2022) addressed these issues in their excellent review.
Exploring the Impact of Random Guessing in Distractor Analysis
Authors: Jin Kuan‐Yu , Siu Wai‐Lok , Huang Xiaoting
Published: March 2022

Multiple‐choice (MC) items are widely used in educational tests. Distractor analysis, an important procedure for checking the utility of response options within an MC item, can be readily implemented in the framework of item response theory (IRT). Although random guessing is a popular behavior of test‐takers when answering MC items, none of the existing IRT models for distractor analysis have considered the influence of random guessing in this process. In this article, we propose a new IRT model to distinguish the influence of random guessing from response option functioning. A brief simulation study was conducted to examine the parameter recovery of the proposed model. To demonstrate its effectiveness, the new model was applied to the mathematics tests of the Hong Kong Diploma of Secondary Education Examination (HKDSE) from 2015 to 2019. The results of empirical analyses suggest that the complexity of item contents is a key factor in inducing students’ random guessing. The implications and applications of the new model to other testing situations are also discussed.
Safety, pharmacokinetic, and pharmacodynamic study of sibofimloc, a novel FimH blocker in patients with active Crohn's disease
Authors: Reinisch Walter , Hébuterne Xavier , Buisson Anthony , Schreiber Stefan , Desreumaux Pierre , Primas Christian , Paillarse Jean‐Michel , Chevalier Grégoire , Bonny Christophe
Published: March 2022

Background and Aim

Expression of FimH adhesin by invasive Escherichia coli in the gastrointestinal tract of patients with Crohn's disease (CD) facilitates binding to epithelial glycoproteins and release of pro‐inflammatory cytokines. Sibofimloc is a first‐in‐class FimH blocker that showed little systemic absorption in healthy volunteers. The current study evaluated systemic absorption, safety, and effect on inflammatory biomarkers of sibofimloc in patients with CD.

Methods

This was an open‐label, multicenter phase 1b study in adults with active CD. In part 1, two patients received a single oral dose of 3000‐mg sibofimloc followed by 1500 mg b.i.d. for 13 days. In part 2, six patients received 1500‐mg sibofimloc b.i.d. for 13 days. Blood was drawn for pharmacokinetic and biomarker analysis, and stool was collected for biomarker and microbiome analysis.

Results

Eight patients with active ileal or ileocolonic CD were enrolled into the study. Systemic sibofimloc exposure was low. Sibofimloc was well tolerated with only grade 1–2 events observed. Several pro‐inflammatory biomarkers, including IL‐1β, IL‐6, IL‐8, TNF‐α, IFN‐γ, and calprotectin, were decreased in stool by end of study.

Conclusions

This first study of the novel FimH blocker, sibofimloc, in patients with active CD demonstrated minimal systemic exposure with good tolerance, while decreasing several inflammatory biomarkers.

EudraCT number: 2017‐003279‐70.
Subject satisfaction and psychological well‐being with escalating abobotulinumtoxinA injection dose for the treatment of moderate to severe glabellar lines
Authors: Dayan Steven , Joseph John , Moradi Amir , Lorenc Z. Paul , Coleman Kyle , Ablon Glynis , Kaufman‐Janette Joely , Cox Sue Ellen , Campbell Andrew , Munavalli Girish , Prygova Inna
Published: March 2022

Background

Previous studies indicate that the efficacy and durability of a single AbobotulinumtoxinA (ABO) treatment for moderate to severe glabellar lines may be enhanced with increasing dose, while safety outcomes remain consistent with those of the licensed dose (50 U).

Aims

Evaluation of subject‐reported indicators of treatment efficacy, satisfaction, and psychological well‐being with ABO dose escalation.

Methods

A Phase 2, 36‐week, multicenter, randomized, dose‐ranging, double‐blind, placebo‐controlled study was conducted in adults with moderate to severe glabellar lines. Subjects received a single ABO treatment, dosed at 50, 75, 100, or 125 U, or placebo. Efficacy endpoints comprised subject‐assessed improvement in line severity of ≥1‐grade from baseline at maximum frown, global aesthetic improvement scale (GAIS) grade, FACE‐Q™ appraisal of lines, psychological well‐being and age, and subject satisfaction.

Results

The study included 399 subjects (88.2% were female). Respective responder rates (≥1‐grade improvement) with ABO 50–125 U doses ranged between 96.3%–100% at Week 4, 65.0%–67.9% at Week 24, and 33.8%–44.4% at Week 36. GAIS responder rate and FACE‐Q appraisal of lines showed a similar pattern of change. Satisfaction was high and psychological well‐being was improved from Week 4 through Week 36, with natural, youthful, and refreshed appearance reported for all ABO doses.

Conclusions

A single ABO treatment (dosed at 50–125 U) provided significant and sustained improvements in glabellar line severity over durations up to 36 weeks, versus placebo. Treatment satisfaction was high with all doses. Participants reported natural and youthful appearance, alongside improvements in psychological well‐being.
Associations Between State Laws Governing Recess Policy with Children's Physical Activity and Health
Authors: Clevenger Kimberly A. , Perna Frank M. , Moser Richard P. , Berrigan David
Published: March 2022

Background

State‐level laws governing recess policies vary widely across the United States. We characterize the presence of such laws and assess their associations with child‐level outcomes.

Methods

The presence of a state recess law was determined using the Classification of Laws Associated with School Students (CLASS) database. Parents of 6‐ to 11‐year‐old children reported physical activity, overall health, school absences, school‐related problems, and ability to make/keep friends as part of the National Survey of Children's Health (NSCH). Logistic regression was used to compare outcomes in states with and without recess laws cross‐sectionally in 2018 and between 2003 and 2011/2012 using a difference‐in‐differences analysis.

Results

In 2018, 20 states had a law recommending or requiring recess. Cross‐sectionally, the odds of being physically active every day (odds ratio, 95% confidence interval: 2.8, 1.2‐6.5) and having no difficulty making or keeping friends (2.9, 1.2‐7.2) were significantly higher for children residing in states with versus without a recess law. There were no significant associations in the difference‐in‐differences model.

Conclusions

Significant cross‐sectional associations in 2018 were not confirmed by a difference‐in‐differences analysis of two waves of the NSCH. Short follow‐up time and the apparent weakness of existing state laws warrant further assessment of state‐level recess law.
Elevated expression of urokinase plasminogen activator in rodent models and patients with cerebral amyloid angiopathy
Authors: Vervuurt Marc , Zhu Xiaoyue , Schrader Joseph , de Kort Anna M. , Marques Tainá M. , Kersten Iris , Peters van Ton Annemieke M. , Abdo Wilson F. , Schreuder Floris H. B. M. , Rasing Ingeborg , Terwindt Gisela M. , Wermer Marieke J. H. , Greenberg Steven M. , Klijn Catharina J. M. , Kuiperij H. Bea , Van Nostrand William E. , Verbeek Marcel M.
Published: March 2022

Aims

The aim of this work is to study the association of urokinase plasminogen activator (uPA) with development and progression of cerebral amyloid angiopathy (CAA).

Materials and methods

We studied the expression of uPA mRNA by quantitative polymerase chain reaction (qPCR) and co‐localisation of uPA with amyloid‐β (Aβ) using immunohistochemistry in the cerebral vasculature of rTg‐DI rats compared with wild‐type (WT) rats and in a sporadic CAA (sCAA) patient and control subject using immunohistochemistry. Cerebrospinal fluid (CSF) uPA levels were measured in rTg‐DI and WT rats and in two separate cohorts of sCAA and Dutch‐type hereditary CAA (D‐CAA) patients and controls, using enzyme‐linked immunosorbent assays (ELISA).

Results

The presence of uPA was clearly detected in the cerebral vasculature of rTg‐DI rats and an sCAA patient but not in WT rats or a non‐CAA human control. uPA expression was highly co‐localised with microvascular Aβ deposits. In rTg‐DI rats, uPA mRNA expression was highly elevated at 3 months of age (coinciding with the emergence of microvascular Aβ deposition) and sustained up to 12 months of age (with severe microvascular CAA deposition) compared with WT rats. CSF uPA levels were elevated in rTg‐DI rats compared with WT rats (p = 0.03), and in sCAA patients compared with controls (after adjustment for age of subjects, p = 0.05 and p = 0.03). No differences in CSF uPA levels were found between asymptomatic and symptomatic D‐CAA patients and their respective controls (after age‐adjustment, p = 0.09 and p = 0.44). Increased cerebrovascular expression of uPA in CAA correlates with increased quantities of CSF uPA in rTg‐DI rats and human CAA patients, suggesting that uPA could serve as a biomarker for CAA.
“Not everybody approaches it that way”: Nurse‐trained health department directors’ leadership strategies and skills in public health
Authors: Kett Paula M. , Bekemeier Betty , Altman Molly R. , Herting Jerald R.
Published: March 2022

Evidence points to nurses as possessing particular skills which are important for public health leadership; in particular, investigators have found that a nurse public health director is strongly associated with positive health department performance. To better understand this association and to guide the effective deployment of nurse leaders, researchers sought to explore the specific leadership strategies used by nurse public health directors, using a critical thematic analysis approach to examine these leadership strategies in the context of certain ideologies, power differentials, and social hierarchies. Data were collected via semistructured interviews conducted from July to September 2020 with 13 nurse public health directors from across the United States. Major themes illustrate a distinct picture of the nursing approach to public health leadership: (a) approaching their work with an other‐focused lens, (b) applying theoretical knowledge, (c) navigating the political side of their role, and (d) leveraging their nursing identity. Findings articulate the nurse public health director's distinctive combination of skills which reflect the interprofessional nature of public health nursing practice. Such skills demonstrate a specialized approach that may set nurse leaders apart from other types of leaders in carrying out significant public health work.
Analysis of the radial and ulnar arteries using ultrasound and a vascular visualization device in children
Authors: Kemmochi Makoto , Nawa Yuko , Ohno Sho , Sawashita Yasuaki , Terada Hirofumi , Oba Koji
Published: March 2022

Background

Radial artery is the preferred site for cannulation. Recently, the ulnar artery was chosen as an alternative in adults.

Aims

We aimed to measure the diameter and depth of the ulnar and radial arteries using ultrasound, and our secondary purpose was to evaluate their anatomical position using a near‐infrared transcutaneous illumination device.

Methods

Forty‐eight children (age range: 0–144 months) were assigned to the following groups: group Infant (aged <12 months), group Preschool (aged ≤12 to <72 months), and group School (aged ≥72 months). The diameter, depth, and position of the ulnar and radial arteries were compared between groups.

Results

There was no significant difference between the diameters of the ulnar and radial arteries. In group Infant, group Preschool, and group School, mean diameters of the ulnar artery were 1.27 ± 0.15 mm, 1.62 ± 0.27 mm, and 2.03 ± 0.28 mm, respectively, and the radial artery were 1.29 ± 0.15 mm, 1.69 ± 0.27 mm, and 2.06 ± 0.29 mm, respectively. The corresponding differences between the diameters of ulnar and radial arteries were −0.02 mm, −0.07 mm, and −0.02 mm [95% CI −0.16 mm to 0.12 mm, −0.25 mm to 0.11 mm, and −0.25 mm to 0.21 mm; p = .776, p = .411, and p = .852]. In groups Preschool and School, the ulnar artery was at the recommended depth of 2–4 mm for arterial cannulation compared with the radial artery. In the Infant, Preschool, and School age groups, the ulnar and radial arteries were at the recommended depth of 2–4 mm for arterial cannulation in 70.0%, 100.0%, 93.8%, and 80.0%, 65.0%, and 50.0% of the cases, respectively. (difference: −10.0%, 35.0%, and 43.8%, 95%; CI −43.4% to 23.4%, 14.1% to 55.9%, and 19.4% to 68.1%, respectively).

Conclusions

The ulnar artery can be considered a promising alternative to the radial artery for facilitating arterial cannulation in children.
Interferon‐gamma induces melanogenesis via post‐translational regulation of tyrosinase
Authors: Mo Xuan , Kazmi Hasan Raza , Preston‐Alp Sarah , Zhou Bo , Zaidi M. Raza
Published: March 2022

Melanogenesis (melanin pigment production) in melanocytes is canonically stimulated by the alpha melanocyte stimulating hormone (αMSH), which activates the cyclic‐AMP‐mediated expression of the melanocyte inducing transcription factor (MITF) and its downstream melanogenic genes, including the principal rate‐limiting melanogenic enzyme tyrosinase (TYR). Here, we report that interferon‐gamma (IFNG; type II interferon), but not interferon‐alpha (a type I interferon), induces a noncanonical melanogenic pathway in mouse and human melanocytic cells. Inhibition of IFNG pathway by the JAK1/2 inhibitor ruxolitinib or knocking out Stat1 gene abrogated the IFNG‐induced melanogenesis. Interestingly, IFNG‐induced melanogenesis was independent of MITF. IFNG markedly increased the TYR protein expression but did not affect the mRNA expression, suggesting a post‐translational regulatory mechanism. In contrast, IFNG had no effect on the expression of other melanogenesis‐related proteins, for example, tyrosinase‐related protein 1 (TYRP1) and dopachrome tautomerase (DCT). Glycosidase digestion assays revealed that IFNG treatment increased the mature glycosylated form of TYR, but not its de novo synthesis. Moreover, cycloheximide chase assay showed that degradation of TYR was decreased in IFNG‐treated cells. These results suggest that the IFNG‐STAT1 pathway regulates melanogenesis via regulation of the post‐translational processing and protein stability of TYR.
Crowdsourcing and COVID‐19: How Public Administrations Mobilize Crowds to Find Solutions to Problems Posed by the Pandemic
Authors: Colovic Ana , Caloffi Annalisa , Rossi Federica
Published: March 2022

We discuss how public administrations have used crowdsourcing to find solutions to specific problems posed by the COVID‐19 pandemic, and to what extent crowdsourcing has been instrumental in promoting open innovation and service co‐creation. We propose a conceptual typology of crowdsourcing challenges based on the degree of their openness and collaboration with the crowd that they establish. Using empirical evidence collected in 2020 and 2021, we examine the extent to which these types have been used in practice. We discuss each type of crowdsourcing challenge identified and draw implications for public policy.
Growth of the airway smooth muscle layer from late gestation to childhood is mediated initially by hypertrophy and subsequently hyperplasia
Authors: Wang Kimberley C. W. , Donovan Graham M. , Saglani Sejal , Mauad Thais , James Alan L. , Elliot John G. , Noble Peter B.
Published: March 2022

Background and objective

The airway smooth muscle (ASM) layer thickens during development. Identifying the mechanism(s) for normal structural maturation of the ASM reveals pathways susceptible to disease processes. This study characterized thickening of the ASM layer from foetal life to childhood and elucidated the underlying mechanism in terms of hypertrophy, hyperplasia and extracellular matrix (ECM) deposition.

Methods

Airways from post‐mortem cases were examined from seven different age groups: 22–24 weeks gestation, 25–31 weeks gestation, term (37–41 weeks gestation), <0.5 year, 0.5–1 year, 2–5 years and 6–10 years. The ASM layer area (thickness), the number and size of ASM cells and the volume fraction of ECM were assessed by planimetry and stereology.

Results

From late gestation to the first year of life, normalized ASM thickness more than doubled as a result of ASM hypertrophy. Thereafter, until childhood, the ASM layer grew in proportion to airway size, which was mediated by ASM hyperplasia. Hypertrophy and hyperplasia of ASM were accompanied by a proportional change in ECM such that the broad composition of the ASM layer was constant across age groups.

Conclusion

These data suggest that the mechanisms of ASM growth from late gestation to childhood are temporally decoupled, with early hypertrophy and subsequent proliferation. We speculate that the developing airway is highly susceptible to ASM thickening in the first year of life and that the timing of an adverse event will determine structural phenotype.
Griswold for Google: Algorithmic Determinism and Decisional Privacy
Authors: Fairfield Joshua , Reynolds Nathaniel
Published: March 2022

As surveillance capitalism continues to collect data and automate decisions, those on the receiving end of such actions are often rendered speechless. We are less left in awe of the great force of these technologies than we lack the language that could properly define and defend against their onslaught. Often, we feel powerless as our data is extracted then aimed at us to manipulate our own choices, and yet the conversation around these practices seems stultified. Algorithms have shifted the technological landscape by co‐opting human decision‐making and in the process co‐opted the very tool that we use to respond to such changes—our ability to create language through individual action and collective reasoning.

Humans deal with shifting technological landscapes by evolving their language. Language development starts with individual decisions that are then justified and presented to the group for judgment. As a result, moral frameworks develop, and over time legal language is shifted as common law courts and legislatures adopt new moral structures into legal code. Algorithms threaten to displace human decision‐making. Algorithms act, but unlike humans, they do not offer reasons. They halt the development of language by removing human decision‐making and cutting short the supply of decision‐rationales that fuel the conversation. The conversation can be reinvigorated by iterating and upgrading our language to apply to new situations and technological contexts.

We apply this language theory to decisional privacy. Decisional privacy dictates that some realms of human decision, like sex and reproduction, so implicate private life that the government is held to be restrained by constitutional principles. These cases protect people’s capacity to make decisions and, by extension, our ability to provide and judge rationalizations for actions. Decided in the context of twentieth century totalitarianism, decisional privacy cases sought to prevent government inference in private life, but now the greatest threat to private life is corporate, not government. The context has shifted, and so too should our protections for private decisions. We offer the discussion of decisional privacy as a starting point in the conversation about moral constructions. That line of cases represents an acknowledgement of essential human values. People have the capability to make decisions regarding their home, family, health, and children. By preserving the essential ethic of these cases, we can preserve the process of decision‐rationale‐judgment that fuels our conversations, developing moral frameworks. Iterating the language of decisional privacy against instrumentarian corporate actors allows us to keep the conversation about algorithmic determinism open as we develop new ways of describing and defending against invasions into our private life.
Global value chains, trade shocks and jobs: An application to Brexit
Authors: Vandenbussche Hylke , Connell William , Simons Wouter
Published: March 2022

We develop a network trade model with country‐sector level input–output linkages with the objective of evaluating the impact of trade shocks. This framework is particularly useful to decompose the direct and the indirect trade effects of both a bilateral and a third country trade shock, evaluated at the country‐sector level. Using the sectoral World Input–Output Database (WIOD) combined with sectoral employment data, we evaluate the impact in terms of value added and employment of different scenarios of Brexit for 56 industries in the 27 Member States of the European Union, as well as the United Kingdom. In this respect, we consider both the results under the current EU–UK Trade agreement, as well as a counterfactual scenario in which WTO tariffs would apply. In contrast to other studies, we find EU‐27 value added and job losses to be substantially higher than hitherto believed as a result of the closely integrated EU network structure. Our approach finds that upstream sectors are particularly vulnerable to indirect trade shocks effects due to their network centrality.
Baseline assessment findings of the Africa Society for Blood Transfusion Step‐Wise Accreditation Programme in 10 sub‐Saharan African countries, 2016–2018
Authors: Kanagasabai Udhayashankar , Qualls Michael , Shiraishi Ray W. , Eno Laura , Zungu Innocent , Bust Lesley , Drammeh Bakary , Selenic Dejana
Published: March 2022

Background and Objectives

The accreditation of blood services promotes continuous quality improvement in blood and transfusion services. The Africa Society for Blood Transfusion (AfSBT) conducted 20 baseline assessments of National Blood Transfusion Services (NBTS) or blood banks as part of the Step‐Wise Accreditation Programme (SWAP) in 10 sub‐Saharan African (SSA) countries from 2016 to 2018. This paper aims to elucidate the process and findings of the baseline assessments.

Materials and Methods

This is a descriptive study of 20 baseline assessments of NBTS. Eleven sections of the AfSBT assessment were reviewed, and 48 out of 68 standards and 356 out of 466 criteria were assessed. Each standard was assigned a value of 1 if it was fully achieved, 0.5 if partially achieved and 0 if not achieved. We defined average section scores >75% as having ‘met AfSBT Standards’, ≤25% as not meeting standards, 26%–50% as needs major improvement, and 51%–75% as needs some improvement and >75% as meets standards.

Results

The AfSBT SWAP standards were met in 4 out of the 11 sections: donor management, blood collection, component production and compatibility testing. Three sections were determined to need some improvement (quality system; handling, transport and storage and testing of donated blood), and three sections were determined to need major improvement (haemovigilance, blood administration and national blood service accreditation). One section (receipt, ordering, and issuing of blood) did not meet standards.

Conclusion

Despite improvements in the quality of blood services in SSA over the past two decades, governments may consider the importance of prioritizing investments in NBTS, ensuring these institutions meet international accreditation standards that are aligned with safe blood transfusion services.
Negociación de renta variable en el mercado local y en el Mercado Global Colombiano: de la norma a la práctica
Authors: Molano Camacho Daniel
Published: March 2022

El presente artículo estudia la forma en la que se lleva a cabo la negociación de renta variable en Colombia desde una perspectiva jurídica y práctica. Para ello, la investigación analiza el marco teórico-jurídico de este segmento del mercado de valores, y lo acompasa con la experiencia práctica de la operación bursátil en el país. En particular, el estudio elabora y combina los aspectos jurídicos y prácticos del funcionamiento de las ruedas de negociación en Colombia, ilustrando sobre un aspecto poco abordado desde el punto de vista del Derecho, esto es, la celebración de operaciones de mercado por medio de ruedas en los sistemas de negociación.
La democracia electrónica en Colombia
Authors: Molina Betancur Carlos Mario , Silva Arroyave Sergio Orlando
Published: March 2022

Para identificar los avances del gobierno colombiano en la regulación de la democracia electrónica y mejorar su implementación es necesario aclarar el concepto de gobierno electrónico y distinguirlo de la democracia electrónica. Esto se debe a que el uso actual del gobierno electrónico excede sus límites teóricos y dogmáticos y entra en el significado de democracia electrónica. Esta confusión se produjo en Colombia desde el diseño de la primera política de “Gobierno en línea”. La misma debe ser aclarada, porque de lo contrario se corre el riesgo de creer erróneamente que todos los avances que se realicen en el área del gobierno electrónico necesariamente tienen como objetivo generar avances hacia la democracia electrónica. Este artículo de investigación, que sigue un método analítico-descriptivo, busca identificar si el uso de las TIC por parte del gobierno colombiano realmente ha mejorado la calidad de su democracia y reconocer las acciones que se deben tomar para implementar eficientemente la regulación de la democracia electrónica.
Analysis of Solar Irradiance Variation on Heat Flux and Temperature Distribution for a Dish Concentrator Receiver
Authors: Bekele Endeshaw Alemu , Ancha Venkata Ramayya , Binchebo Tarekegn Limore
Published: March 2022

Concentrated solar power presents immense scope for the deployment of small-scale units focusing on diverse applications, including process heat and rural on/off-grid applications. This paper presents the analysis of solar irradiance variation on heat flux and temperature distribution at the dish concentrator receiver. A solar dish concentrator with a 2.8-m aperture diameter and a 0.4-m depth was used for this analysis. The solar ray intersection between a dish concentrator and its receiver, along with the heat flux distribution prediction, was carried out using SolTrace. The effect of flux intensity variation on temperature distribution at the receiver was investigated using comsol multiphysics. The optical analysis considered 10,000 rays, and 91.65% of them were observed to reach the surface of the receiver. For 1000 W/m2 of beam solar radiation, a peak heat flux and maximum temperature at the concentrator’s focal plane are found to be 32.4 MW/m2 and 923 K, respectively. The validation had been done using previously reported results in the literature to verify the correctness of the present simulation results. The effect of beam solar radiation variation on heat flux intensity and the temperature distribution revealed that both heat flux and temperature increase with increasing solar radiation, which points out the influence of design and operating conditions. Apart from PillBox and Gaussian distributions, the effect of slope and specularity errors was characterized, suggesting a greater sensitivity to the former than the latter.
Nonlinear Multimodal Model for Tuned Sloshing Dampers With Nonflat Bottoms
Authors: Love J. S. , Tait M. J.
Published: March 2022

A third-order nonlinear multimodal model is developed for tanks with nonflat bottoms. A six-node finite element model is used to determine the mode shapes of the velocity potential and the associated natural sloshing frequencies. Using this modal information, equations of motion are developed that accommodate the nonlinear coupling among the first three sloshing modes. Damping arising from screens is incorporated into the model using the principle of virtual work. The equations of motion are ordinary differential equations that are solved using the Runge–Kutta–Gill numerical time-stepping method. The model is evaluated with an existing third-order nonlinear multimodal model for a flat-bottom tank and is found to be in excellent agreement. Demonstrative simulations are conducted for tanks with sloped-, boxed-, and ramped-bottoms. The resulting sloshing forces and wave heights at the tank end wall are calculated and presented using time series plots and frequency response plots. The excitation of higher-order sloshing modes through modal coupling results in larger wave heights, and shallower wave troughs. The sloshing forces are less impacted by the responses of higher modes. Secondary resonances are clearly visible in several frequency response plots at frequencies that correspond to the natural sloshing frequency of a higher-order mode divided by an integer. The model is applicable to tanks that are of intermediate water depth with moderate excitation amplitudes, where the response of the second- and third-order sloshing modes are less than the fundamental mode.
Contact Nonlinearity in Indenter–Foam Dampers
Authors: Liu Lejie , Yerrapragada Karthik , Henak Corinne R. , Eriten Melih
Published: March 2022

In this paper, the nonlinear response of indenter–foam dampers is characterized. Those dampers consist of indenters pressed on open-cell foams swollen with wetting liquids. Recently, the authors identified the dominant mechanism of damping in those dampers as poro-viscoelastic (PVE) relaxations as in articular cartilage, one of nature’s best solutions to vibration attenuation. Those previous works by the authors included dynamic mechanical analyses of the indenter–foam dampers under small vibrations, i.e., linear regime. The current study features the dynamic response of similar dampers under larger strains to investigate the nonlinear regime. In particular, the indenter–foam dampers tested in this paper consist of an open-cell polyurethane foam swollen with castor oil. Harmonic displacements are applied on the swollen and pre-compressed foam using a flat-ended cylindrical indenter. Measured forces and corresponding hysteresis (force–displacement) loops are then analyzed to quantify damping performance (via specific damping capacity) and nonlinearities (via harmonic ratio). The effects of strain and strain rates on the damping capacity and harmonic ratio are investigated experimentally. The dominant source of the nonlinearity is identified as peeling at the indenter–foam interface (and quantified via peeling index). A representative model consisting of a linear viscoelastic foam and rate-dependent adhesive interface (slider element with limiting adhesive strength) explains the observed trends in peeling and thus nonlinear dynamic response. Possible remedies to suppress those nonlinearities in future designs of indenter–foam dampers are also discussed.
A Workflow for 3D Reconstruction and Quantification of the Monkey Optic Nerve Head Vascular Network
Authors: Lee Po-Yi , Hua Yi , Brazile Bryn , Yang Bin , Wang Lin , Sigal Ian A.
Published: March 2022

A comprehensive characterization of the 3D vascular network of the optic nerve head (ONH) is critical to understanding eye physiology and pathology. Current in vivo imaging technologies, however, do not have simultaneous high spatial resolution and imaging depth to resolve the small vessels deep within the ONH. We describe a workflow for the 3D reconstruction and quantitative morphological analysis of the ONH vasculature. The vessels of a normal monkey ONH were perfusion labeled. Serial cryosections of the ONH were imaged using fluorescence microscopy (FM) and instant polarized light microscopy (IPOL) to visualize the labeled vessels and label-free collagen, respectively. The IPOL images were registered and used to form a stack of FM images from which the vessels were segmented and skeletonized to reconstruct the 3D vascular network. The network consisted of 12,966 vessel segments, 7,989 branching points, and 1,100 terminal points at the boundaries. For each vessel segment, we measured its length, tortuosity, inclination (θ), and polar orientation (f). The length followed a lognormal distribution, whereas the distribution of the tortuosity followed an exponential decay. The vessels were mainly oriented towards the coronal plane (θ = 90º). For orientation, there were nearly as many vessels aligned circumferentially (f = 90º) and radially (φ = 0º). Our results demonstrate the workflow for 3D eye-specific reconstruction and quantification of the monkey ONH vascular network. This is a critical first step to analyze the blood flow and oxygenation within the ONH, which will help understand the role of vascular dysfunction in glaucoma.
In situ continuous electrochemical quantification of bacterial adhesion to electrically polarized metallic surfaces under shear
Authors: Jones A.-Andrew D. , Buie Cullen R.
Published: March 2022

Biofouling creates significant human and economic losses through infections, corrosion, and drag losses on ships and in oil and food distribution pipelines. Organisms adhered to these surfaces contend with high shear rates and are actively transported to the surface. The metallic surfaces to which these organisms are adhered also conduct charge at various potentials, and the effects of surface charge on adhesion rates are little addressed in the literature. We demonstrate that mass-transport limiting current, chronoamperometry, and cyclic voltammetry can be combined to provide resulting adhesion rates similar to those in the literature. Furthermore, we demonstrate that rotating disk electrodes can be used to study adhesion of bacteria to electrically polarized metallic surfaces under shear. We study the adhesion of Escherichia coli, Bacillus subtilis, and 1μm silica microspheres over a range of shear stress from 0.15 to 37 dyncm−2 or shear rates of 14.7–3730 s−1. Unlike quartz-crystal microbalance, our methodology measures changes in the area instead of mass, simultaneously providing measurements of the protein binding. Our deposition rates agree with those found using optical systems. However, unlike optical systems, our methods apply to a wider range of materials than on-chip flow devices.
Effects of aging and hearing loss on perceptual and electrophysiological measures of pulse-rate discrimination
Authors: DeVries Lindsay , Anderson Samira , Goupell Matthew J. , Smith Ed , Gordon-Salant Sandra
Published: March 2022

Auditory temporal processing declines with age, leading to potential deleterious effects on communication. In young normal-hearing listeners, perceptual rate discrimination is rate limited around 300 Hz. It is not known whether this rate limitation is similar in older listeners with hearing loss. The purpose of this study was to investigate age- and hearing-loss-related rate limitations on perceptual rate discrimination, and age- and hearing-loss-related effects on neural representation of these stimuli. Younger normal-hearing, older normal-hearing, and older hearing-impaired listeners performed a pulse-rate discrimination task at rates of 100, 200, 300, and 400 Hz. Neural phase locking was assessed using the auditory steady-state response. Finally, a battery of non-auditory cognitive tests was administered. Younger listeners had better rate discrimination, higher phase locking, and higher cognitive scores compared to both groups of older listeners. Aging, but not hearing loss, diminished neural-rate encoding and perceptual performance; however, there was no relationship between the perceptual and neural measures. Higher cognitive scores were correlated with improved perceptual performance, but not with neural phase locking. This study shows that aging, rather than hearing loss, may be a stronger contributor to poorer temporal processing, and cognitive factors such as processing speed and inhibitory control may be related to these declines.
Scattering by a rigid sphere of audio sound generated by a parametric array loudspeaker
Authors: Zhong Jiaxin , Kirby Ray , Karimi Mahmoud , Zou Haishan , Qiu Xiaojun
Published: March 2022

This work investigates the scattering by a rigid sphere of audio sound generated by a parametric array loudspeaker (pal). A computationally efficient method utilizing a spherical harmonic expansion is developed to calculate the quasilinear solution of audio sound fields based on both Kuznetsov and Westervelt equations. The accuracy of using the Westervelt equation is examined, and the rigid sphere scattering effects are simulated with the proposed method. It is found the results obtained using the Westervelt equation are inaccurate near the sphere at low frequencies. Contrary to conventional loudspeakers, the directivity of the audio sound generated by a pal severely deteriorates behind a sphere, as the ultrasounds maintaining the directivity of the audio sound are almost completely blocked by the sphere. Instead, the ultrasounds are reflected and generate audio sound on the front side of the sphere. It means that a listener in front of the pal will hear the audio sound scattered back after introducing the sphere as if it is reflected by the sphere. The experiment results are also presented to validate the numerical results.
Immersed boundary methods in wave-based virtual acoustics
Authors: Bilbao Stefan
Published: March 2022

Volumetric wave-based simulation methods for room and virtual acoustics, such as the finite difference time domain method, are computationally intensive; for large volumes, operation over a regular grid is desirable for the sake of efficiency. In coping with realistic irregular geometries (such as enclosures or scattering objects), form-fitting meshing can disturb grid regularity and introduce new difficulties in terms of maintaining numerical stability. An alternative is the immersed boundary method, allowing for the representation of an irregular boundary over a regular grid through additional forcing terms in the dynamical system. While heavily used in fluid-structure interaction problems, such methods have seen less application in virtual acoustics. In this article, a simplified form of the immersed boundary method tailored to virtual acoustics is presented. Under appropriate passivity-preserving discretisation techniques, simple numerical stability conditions can be proved, and in particular, impedance boundaries may be incorporated easily without any risk of numerical instability. In addition, the method retains a largely explicit character with a small linear system solution required over the immersed boundary surface. Numerical results in two and three dimensions, illustrating various interior and exterior problem scenarios, are presented.
The Experiences of High-Performance Female Coaches in Luxembourg
Authors: Poos Laura , Carson Fraser
Published: March 2022

Recent literature has noted the underrepresentation of women in high-performance (HP) coaching and the challenges faced when they do succeed in gaining entry to this male-dominated domain. Initiatives have been implemented in developed sporting nations to address this. However, less is known regarding the experience of women coaching at HP level in small, economically advanced countries and metropolises, where a number of additional sociocultural barriers exist. Underpinned by LaVoi and Dutove’s ecological model, six women currently coaching at HP level in the Grand Duchy of Luxembourg were interviewed, reflecting on their experiences in their role. A social phenomenological analysis approach was taken, with a deductive thematic analysis identifying 32 raw data themes: five supports (e.g., passion for the job) and four barriers (e.g., personal sacrifices) were reported at individual level; five supports (e.g., family support) and three barriers (e.g., lack of federation support) identified at interpersonal level; three supports (e.g., open communication environment) and seven barriers (e.g., lack of entry opportunities) noted at organizational level; and two supports (e.g., increased acceptance by male athletes) and three barriers (e.g., hegemonic masculinity) described at societal level. Further challenges exist in Luxembourg due to coaching not being seen as a legitimate career pathway and an underlying cultural expectation for women to manage domestic duties. The structure of the coach education system in Luxembourg makes it possible to address these barriers and enable a more diverse workforce in leadership positions in HP sport. Doing so should create more opportunities and support for women in coaching.
Gender-responsive social protection post–COVID-19
Authors: Gavrilovic Maja , Rubio Monica , Bastagli Francesca , Hinton Roopa , Staab Silke , Goulder Ruth Graham , Bilo Charlotte , Khan Ruby , Peterman Amber , Diallo Bobo , Alfers Laura , Santiago Aroa , Rizvi Zehra , Holmes Rebecca , Mejia Juan Gonzalo Jaramillo , Tabbush Constanza
Published: March 2022

Investment in gender-responsive social protection systems and evidence is key to a more equal future post–COVID-19
All hail the Queen of Carbon
Carbon Queen: The Remarkable Life of Nanoscience Pioneer Mildred Dresselhaus
Maia Weinstock
MIT Press, 2022. 320 pp.
Authors: Venkatraman Vijaysree
Published: March 2022

A new biography solidifies the legacy of a pioneering and prolific nanoscientist
The right shoe for the job
Authors: Gandavadi Dhanush , Hariadi Rizal F.
Published: March 2022

Natural dynein protein motors are reengineered to walk on specific artificial DNA tracks
“Back to normal” is not enough
Authors: Pagel Christina
Published: March 2022

As the world reflects on 2 years of the COVID-19 pandemic, we need to change how to tackle the enormous challenges of the future. The good news is that the past 2 years of the COVID-19 pandemic have shown that change is possible.
Impact crater under Greenland’s ice is surprisingly ancient
Authors: Voosen Paul
Published: March 2022

New date of 58 million years undercuts idea that strike triggered recent Younger Dryas climate cooling
Mild SARS-CoV-2 infection in rhesus macaques is associated with viral control prior to antigen-specific T cell responses in tissues
Authors: Nelson Christine E. , Namasivayam Sivaranjani , Foreman Taylor W. , Kauffman Keith D. , Sakai Shunsuke , Dorosky Danielle E. , Lora Nickiana E. ,   NIAID/DIR Tuberculosis Imaging Program, Brooks Kelsie , Potter E. Lake , Garza Nicole L. , Lafont Bernard A. P. , Johnson Reed F. , Roederer Mario , Sher Alan , Weiskopf Daniela , Sette Alessandro , de Wit Emmie , Hickman Heather D. , Brenchley Jason M. , Via Laura E. , Barber Daniel L. , Abdi Ayan , Dayao Emmuanual K. , Fleegle Joel D. , Gomez Felipe , Piazza Michaela K. , Repoli Katelyn M. , Sloan Becky Y. , Butler Ashley L. , Walker April M. , Weiner Danielle M. , Woodcock Michael J. , Vatthauer Alexandra
Published: March 2022

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily replicates in mucosal sites, and more information is needed about immune responses in infected tissues. Here, we used rhesus macaques to model protective primary immune responses in tissues during mild coronavirus disease 2019 (COVID-19). Viral RNA levels were highest on days 1 to 2 after infection and fell precipitously thereafter.
18
F-fluorodeoxyglucose (
18
FDG)–avid lung abnormalities and interferon (IFN)–activated monocytes and macrophages in the bronchoalveolar lavage (BAL) were found on days 3 to 4 after infection. Virus-specific effector CD8
+
and CD4
+
T cells became detectable in the BAL and lung tissue on days 7 to 10 after viral RNA, radiologic evidence of lung inflammation, and IFN-activated myeloid cells had substantially declined. SARS-CoV-2–specific T cells were not detectable in the nasal turbinates, salivary glands, and tonsils on day 10 after infection. Thus, SARS-CoV-2 replication wanes in the lungs, as well as the nasal and oral mucosa, of rhesus macaques before antigen-specific effector T cells arrive at those sites, suggesting that innate immunity efficiently restricts viral replication during mild COVID-19.
Impact of Short-Term Storage on
Ex Vivo
Antimalarial Susceptibilities of Fresh Ugandan Plasmodium falciparum Isolates
Authors: Okitwi Martin , Orena Stephen , Thomas Katairo , Tumwebaze Patrick K. , Byaruhanga Oswald , Nsobya Samuel L. , Conrad Melissa D. , Bayles Brett R. , Rosenthal Philip J. , Cooper Roland A.
Published: March 2022

We measured susceptibilities of Ugandan
Plasmodium falciparum
isolates assayed on the day of collection or after storage at 4°C. Samples were incubated with serial dilutions of 8 antimalarials, and susceptibilities were determined from 72-h growth inhibition assays.
The CIAMIB: a Large and Metabolically Diverse Collection of Inflammation-Associated Bacteria from the Murine Gut
Authors: Wong Erin Oi-Yan , Brownlie Emma Joan Elizabeth , Ng Katharine Michelle , Kathirgamanathan Sornnujah , Yu Feiqiao Brian , Merrill Bryan D. , Huang Kerwyn Casey , Martin Alberto , Tropini Carolina , Navarre William Wiley
Published: March 2022

Attempts to explore the role of the microbiota in animal physiology have resulted in large-scale efforts to cultivate the thousands of microbes that are associated with humans. In contrast, relatively few lab mouse-associated bacteria have been isolated, despite the fact that the overwhelming number of studies on the microbiota use laboratory mice that are colonized with microbes that are quite distinct from those in humans.