bluuebunny/crossref_metadata_2025 huggingface dataset:
Teaching a hands-on course during corona lockdown: from problems to opportunities
Authors: Hut R W , Pols C F J , Verschuur D J
Published: September 2020

Teaching a hands- and minds-on course, in which feedback is essential in order to learn, is difficult, especially in times of COVID-19 where student progression cannot be monitored directly. During the lockdown period, the workshops of an undergraduate Design Engineering course had to be transferred to the home situation, which required a redesign of this course by the staff. It also provided new opportunities for students to adapt to this situation, which required extra creativity and problem-solving skills. The adapted workshops revealed conditions that enhance maker education. However, providing timely feedback required a substantial amount of time not anticipated for. We also report that short instruction videos seem to work much better than longer lectures or tedious materials. As we practice what we preach, we will evaluate the course and apply our design knowledge acquired over the years.
Collective modes of Weyl fermions with repulsive S-wave interaction*
Authors: Wang Xun-Gao , Wang Huan-Yu , Zhang Jiang-Min , Liu Wu-Ming
Published: September 2020

We calculate the spin and density susceptibility of Weyl fermions with repulsive S-wave interaction in ultracold gases. Weyl fermions have a linear dispersion, which is qualitatively different from the parabolic dispersion of conventional materials. We find that there are different collective modes for the different strengths of repulsive interaction by solving the poles equations of the susceptibility in the random-phase approximation. In the long-wavelength limit, the sound velocity and the energy gaps vary with the different strengths of the interaction in the zero sound mode and the gapped modes, respectively. The particle–hole continuum is obtained as well, where the imaginary part of the susceptibility is nonzero.
Lattice thermal conductivity of β
12 and χ
3 borophene*
Authors: He Jia , Ouyang Yulou , Yu Cuiqian , Jiang Pengfei , Ren Weijun , Chen Jie
Published: September 2020

Borophene allotropes have many unique physical properties due to their polymorphism and similarity between boron and carbon. In this work, based on the density functional theory and phonon Boltzmann transport equation, we investigate the lattice thermal conductivity κ of both β
12 and χ
3 borophene. Interestingly, these two allotropes with similar lattice structures have completely different thermal transport properties. β
12 borophene has almost isotropic κ around 90 W/(m⋅K) at 300 K, while κ of χ
3 borophene is much larger and highly anisotropic. The room temperature κ of χ
3 borophene along the armchair direction is 512 W/(m⋅K), which is comparable to that of hexagonal boron nitride but much higher than most of the two-dimensional materials. The physical mechanisms responsible for such distinct thermal transport behavior are discussed based on the spectral phonon analysis. More interestingly, we uncover a unique one-dimensional transport feature of transverse acoustic phonon in χ
3 borophene along the armchair direction, which results in a boost of phonon relaxation time and thus leads to the significant anisotropy and ultrahigh thermal conductivity in χ
3 borophene. Our study suggests that χ
3 borophene may have promising application in heat dissipation, and also provides novel insights for enhancing the thermal transport in two-dimensional systems.
Exciton emissions of CdS nanowire array fabricated on Cd foil by the solvothermal method*
Authors: Li Yong , Ji Peng-Fei , Hao Ya-Juan , Song Yue-Li , Zhou Feng-Qun , Yuan Shu-Qing
Published: September 2020

Nanowires have recently attracted more attention because of their low-dimensional structure, tunable optical and electrical properties for next-generation nanoscale optoelectronic devices. CdS nanowire array, which is (002)-orientation growth and approximately perpendicular to Cd foil substrate, has been fabricated by the solvothermal method. In the temperature-dependent photoluminescence, from short wavelength to long wavelength, four peaks can be ascribed to the emissions from the bandgap, the transition from the holes being bound to the donors or the electrons being bound to the acceptors, the transition from Cd interstitials to Cd vacancies, and the transition from S vacancies to the valence band, respectively. In the photoluminescence of 10 K, the emission originated from the bandgap appears in the form of multiple peaks. Two stronger peaks and five weaker peaks can be observed. The energy differences of the adjacent peaks are close to 38 meV, which is ascribed to the LO phonon energy of CdS. For the multiple peaks of bandgap emission, from low energy to high energy, the first, second, and third peaks are contributed to the third-order, second-order, and first-order phonon replica of the free exciton A, respectively; the fourth peak is originated from the free exciton A; the fifth peak is contributed to the first-order phonon replica of the excitons bound to neutral donors; the sixth and seventh peaks are originated from the excitons bound to neutral donors and the light polarization parallel to the c axis of hexagonal CdS, respectively.
Investigation of bright and dark solitons in α, β-Fermi Pasta Ulam lattice
Authors: Nfor Nkeh Oma , Yamgoué Serge Bruno , Moukam Kakmeni Francois Marie
Published: September 2020

We consider the Hamiltonian of α, β-Fermi Pasta Ulam lattice and explore the Hamilton–Jacobi formalism to obtain the discrete equation of motion. By using the continuum limit approximations and incorporating some normalized parameters, the extended Korteweg–de Vries equation is obtained, with solutions that elucidate on the Fermi Pasta Ulam paradox. We further derive the nonlinear Schrödinger amplitude equation from the extended Korteweg–de Vries equation, by exploring the reductive perturbative technique. The dispersion and nonlinear coefficients of this amplitude equation are functions of the α and β parameters, with the β parameter playing a crucial role in the modulational instability analysis of the system. For β greater than or equal to zero, no modulational instability is observed and only dark solitons are identified in the lattice. However for β less than zero, bright solitons are traced in the lattice for some large values of the wavenumber. Results of numerical simulations of both the Korteweg–de Vries and nonlinear Schrödinger amplitude equations with periodic boundary conditions clearly show that the bright solitons conserve their amplitude and shape after collisions.
Folding nucleus and unfolding dynamics of protein 2GB1*
Authors: Wei Xuefeng , Wang Yanting
Published: September 2020

The folding of many small proteins is kinetically a two-state process with one major free-energy barrier to overcome, which can be roughly regarded as the inverse process of unfolding. In this work, we first use a Gaussian network model to predict the folding nucleus corresponding to the major free-energy barrier of protein 2GB1, and find that the folding nucleus is located in the β-sheet domain. High-temperature molecular dynamics simulations are then used to investigate the unfolding process of 2GB1. We draw free-energy surface from unfolding simulations, taking RMSD and contact number as reaction coordinates, which confirms that the folding of 2GB1 is kinetically a two-state process. The comparison of the contact maps before and after the free energy barrier indicates that the transition from native to non-native structure of the protein is kinetically caused by the destruction of the β-sheet domain, which manifests that the folding nucleus is indeed located in the β-sheet domain. Moreover, the constrained MD simulation further confirms that the destruction of the secondary structures does not alter the topology of the protein retained by the folding nucleus. These results provide vital information for upcoming researchers to further understand protein folding in similar systems.
Design, modelling, and simulation of a floating gate transistor with a novel security feature
Authors: Zandipour H. , Madani M.
Published: September 2020

This study proposes a new generation of floating gate transistors (FGT) with a novel built-in security feature. The new device has applications in guarding the IC chips against the current reverse engineering techniques, including scanning capacitance microscopy (SCM). The SCM measures the change in the C–V characteristic of the device as a result of placing a minute amount of charge on the floating gate, even in nano-meter scales. The proposed design only adds a simple processing step to the conventional FGT by adding an oppositely doped implanted layer to the substrate. This new structure was first analyzed theoretically and then a two-dimensional model was extracted to represent its C–V characteristic. Furthermore, this model was verified with a simulation. In addition, the C–V characteristics relevant to the SCM measurement of both conventional and the new designed FGT were compared to discuss the effectiveness of the added layer in masking the state of the transistor. The effect of change in doping concentration of the implanted layer on the C–V characteristics was also investigated. Finally, the feasibility of the proposed design was examined by comparing its I–V characteristics with the traditional FGT.
A 0.5–3.0 GHz SP4T RF switch with improved body self-biasing technique in 130-nm SOI CMOS
Authors: Zhang Hao , Cui Qiangsheng , Yan Xu , Shi Jiahui , Lin Fujiang
Published: September 2020

A single-pole four-throw (SP4T) RF switch with charge-pump-based controller is designed and implemented in a commercial 130-nm silicon-on-insulator (SOI) CMOS process. An improved body self-biasing technique based on diodes is utilized to simplify the controlling circuitry and improve the linearity. A multistack field-effect-transistor (FET) structure with body floating technique is employed to provide good power-handling capability. The proposed design demonstrates a measured input 0.1-dB compression point of 38.5 dBm at 1.9 GHz, an insertion loss of 0.27 dB/0.33 dB and an isolation of 35 dB/27 dB at 900 MHz/1.9 GHz, respectively. The overall chip area is only 0.49 mm2. This RF switch can be used in GSM/WCDMA/LTE front-end modules.
Defect levels in d-electron containing systems: Comparative study of CdTe using LDA and LDA + U
Authors: Yin Yuan , Wang Yu , Chen Guangde , Wu Yelong
Published: September 2020

The defect properties in d-electron containing materials will be strongly influenced by the non-negligible on-site Coulomb interactions. However, this has been omitted in the current widely adopted standard first-principles calculations, such as LDA, leading to a large deviation of calculated results. Therefore, as a comparative case study, in this paper the defects of CdTe are investigated by first-principles calculations including standard LDA and LDA + U, and we find that LDA + U gives more accurate formation energies of the neutral point defects than the standard LDA. The same trend can be found in transition energies of the charged state defects as well. These comparative analyses show that LDA + U gives better results for the defects of CdTe than the standard LDA and requires less computing resource than LAPW, indicating it should have huge potential to model supercells with large number of atoms and strong electron interactions. Moreover, a new anion interstitial defect structure is found to be more stable than the well-known tetrahedron central anion interstitial defect structure

.
Stellarator-tokamak energy confinement comparison based on ASDEX Upgrade and Wendelstein 7-X hydrogen plasmas
Authors: Stroth U. , Fuchert G. , Beurskens M.N.A. , Birkenmeier G. , Schneider P.A. , Scott E.R. , Brunner K.J. , Günzkofer F. , Hacker P. , Kardaun O. , Knauer J.P. , Rahbarnia K. , Zhang D.
Published: September 2020

A confinement database with mainly electron-heated hydrogen plasmas from ASDEX Upgrade and Wendelstein 7-X was assembled. Stellarator confinement scaling expressions describe both standard discharges in the stellarator and L-mode plasmas in the tokamak similarly well and indicate a similar quality of energy confinement in both devices. While the energy confinement time in ASDEX Upgrade benefits from the smaller aspect ratio of the device, the transport coefficients in Wendelstein 7-X appear to be smaller possibly due to reduced average magnetic field curvature. A physics based confinement scaling is derived from a model that successfully describes transport in tokamaks. The dimensionally correct scaling has very similar parameter dependencies as the stellarator scalings and reproduces also the trends in the data from ITER L- and H-mode databases reasonably well. On the basis of this scaling, which represents the confinement times of the present data base, average tokamak L-mode and H-mode confinement is 7% lower and 76% higher, respectively.
When IPCC graphs can foster or bias understanding: evidence among decision-makers from governmental and non-governmental institutions
Authors: Fischer Helen , van den Broek Karlijn L , Ramisch Kilian , Okan Yasmina
Published: September 2020

To develop effective climate change policy, decision-makers need to have the best possible understanding of the available climate science. The IPCC Assessment Reports therefore aim to lay the foundation for informed political decision-making by providing policy-relevant information. But how successful are IPCC reports at communicating key findings? Although IPCC reports display key information in graphs, the interpretation of such graphs has received little attention. Here we provide an empirical evaluation of IPCC graph comprehension among IPCC target audience (N = 110), (political) decision-makers from climate-related (non-)governmental organizations from 54 countries, and a comparative sample of German junior diplomats, representing future international decision-makers (N = 33). We assess comprehension of current climate change risk visualizations using two IPCC graphs, one that employs principles of intuitive design, and one that violates principles of intuitive design. Results showed that (i) while a minority of IPCC target audience misinterpreted the intuitive graph, (ii) the majority of participants systematically misinterpreted the counter-intuitive graph, drawing the opposite conclusion from what was meant to be conveyed by the graph, despite (iii) having high confidence in the accuracy of their interpretation. Since misinterpretation of IPCC graphs does not allow for optimal use of the scientific information for policy-making, the results emphasize the importance of IPCC graphs that follow the principles of intuitive design.
Influence of long-range interaction on degeneracy of eigenvalues of connection matrix of d-dimensional Ising system
Authors: Kryzhanovsky B V , Litinskii L B
Published: September 2020

We examine connection matrices of Ising systems with long-rang interaction on d-dimensional hypercube lattices of linear dimensions L. We express the eigenvectors of these matrices as the Kronecker products of the eigenvectors for the one-dimensional Ising system. The eigenvalues of the connection matrices are polynomials of the dth degree of the eigenvalues for the one-dimensional system. We show that including of the long-range interaction does not remove the degeneracy of the eigenvalues of the connection matrix. We analyze the eigenvalue spectral density in the limit L → ∞. In the case of the continuous spectrum, for d ⩽ 2 we obtain analytical formulas that describe the influence of the long-range interaction on the spectral density and the crucial changes of the spectrum.
Correlations in the elastic Landau level of spontaneously buckled graphene
Authors: Manesco A L R , Lado J L , Ribeiro E V S , Weber G , Rodrigues Jr D
Published: September 2020

Electronic correlations stemming from nearly flat bands in van der Waals materials have demonstrated to be a powerful playground to engineer artificial quantum matter, including superconductors, correlated insulators and topological matter. This phenomenology has been experimentally observed in a variety of twisted van der Waals materials, such as graphene and dichalcogenide multilayers. Here we show that spontaneously buckled graphene can yield a correlated state, emerging from an elastic pseudo Landau level. Our results build on top of recent experimental findings reporting that, when placed on top of hBN or NbSe2 substrates, wrinkled graphene sheets relax forming a periodic, long-range buckling pattern. The low-energy physics can be accurately described by electrons in the presence of a pseudo-axial gauge field, leading to the formation of sublattice-polarized Landau levels. Moreover, we verify that the high density of states at the zeroth Landau level leads to the formation of a periodically modulated ferrimagnetic groundstate, which can be controlled by the application of external electric fields. Our results indicate that periodically strained graphene is a versatile platform to explore emergent electronic states arising from correlated elastic Landau levels.
Effect of sulfuric acid concentration on morphology of calcium sulfate hemihydrate crystals
Authors: Wang Yubin , Mao Xinyu , Chen Chang , Wang Wangbo , Dang Weiben
Published: September 2020

Calcium sulfate hemihydrate whiskers were prepared in sulfuric acid-distilled water system by hydrothermal method using calcium sulfate dihydrate as raw materials. The influence mechanism of sulfuric acid concentration on morphology of calcium sulfate hemihydrate crystals was investigated. The results show that the morphology of hydrothermal products is fibrous when the suitable sulfuric acid concentration is from 5.0 × 10−6 mol l−1 to 5.0 × 10−4 mol l−1. The promoting effect of sulfuric acid on the dissolution of calcium sulfate dihydrate increases the amount of Ca2+ in the solution, which is beneficial to the crystallization of calcium sulfate hemihydrate crystals. Meanwhile, the selective adsorption of H+ produced by sulfuric acid ionization on the (310) crystal plane of calcium sulfate hemihydrate crystals can hinder the aggregation of Ca2+ on the crystal plane, which results in preferential growth of the calcium sulfate hemihydrate crystal along the (001) crystal plane. However, when the sulfuric acid concentration is up to 5.0 × 10−3 mol l−1, the

HSO

4

−

produced by the interaction of H+ with

SO

4

2
−

can reduce the electronegativity of

SO

4

2
−

and inhibit

SO

4

2
−

adsorption on the crystal surface. So the growth of calcium sulfate hemihydrate crystals along (001) crystal plane is hindered, which leads to the decrease of the fibrous products.
Pornography
Authors: Alliston April
Published: September 2020

Sexually explicit images are among the oldest known representational artifacts, and yet none of these were ever understood as “pornography” until the word and concept began to emerge in Western European languages during the 19th century. At that time, it was used equally to refer to written texts and visual representations. The word has since entered into much more widespread usage, often referring to any and all sexually explicit material, more often to material that appears specifically designed “to stimulate erotic rather than aesthetic feelings” (Oxford English Dictionary). Since the popularization of internet pornography in the late 20th century, the term has even come to be applied to any image considered to emphasize the pleasure and seduction of the viewer over realistic representation (as in “food porn,” “real estate porn,” etc.). Many attempts have been made to define pornography more specifically, but little consensus has been achieved. Courts of law have generally avoided defining the word “pornography,” preferring to categorize sexually explicit or arousing representations in terms of “obscenity.” Feminist scholars have disagreed on the definition of pornography to the extent that the conflict became known as the “Porn Wars” of the last several decades of the 20th century. Sexually explicit or sexually stimulating representations can elicit powerful emotional responses that vary widely, and they are inextricable from questions of social power. Thus, the very act of defining pornography is implicated in political struggles over some of the most fundamental issues of human life: gender, sexuality, social equality, and the nature and power of representations. There remains no general or stable agreement concerning what it is, what effects it may have, or even whether it exists at all.
The Drug Policy in the Americas From a Gender Perspective
Authors: Salim de Castro Helena
Published: September 2020

In the early 21st century, the number of women incarcerated in Latin America for drug-related offenses has increased dramatically. Many women are engaging in drug trafficking for different reasons, and in most cases, they play inferior roles in the drug supply chain, working as couriers or carrying drugs inside their bodies, which make them vulnerable to the justice system. This increase in female incarceration is one of the consequences of a repressive and prohibitive framework against the use and trafficking of drugs in the Americas. The “War on Drugs” policy was developed in the 1970s by the U.S. government, almost 50 years ago. This policy spread a regional fight against drug use and trafficking, which was reinforced by the United Nations Conventions on Drugs and committees of the Organization of American States.

Even though some international and regional organizations and government institutions have been alarmed by the increase in female incarceration rates, the discussions and documents concerning this issue have some gaps. As analyzed by a feminist and gender literature, stereotypes about femininity persist. The official documents consider women mere victims in the drug world and do not debate their reasons for entering criminality, as an economic necessity, for example. In the same sense, little effort has been made by governments to change the actual repressive anti-drug policy. Focusing just on the lowest level of the drug supply chain, the “War on Drugs” policy continues to drive many people, especially women, younger, and black poor people, to jail.
Honduran Social Movements: Then and Now
Authors: Portillo Suyapa , Padilla Romero Cristian
Published: September 2020

Honduran social movements have historically organized around three important pillars: political parties constituted by both traditional and more radical parties, labor organizing efforts, and campesino-based land struggles. Work and land took formidable shape from the 1900s to the 1930s as workers began pushing back against the unyielding exploitation of U.S.-based banana and mining corporations and resisting. The end of the Tiburcio Carías Andino dictatorship in 1949 gave rise to a militant labor movement and political opposition to the ruling National Party, which came with an uneasy alliance between leftists and the Liberal Party. Workers efforts, bottom up, paved the way for progressive labor and agrarian laws. After World War II (WWII), Hondurans become ensnared by U.S.-led Cold War politics and anti-communism, leading to the 1963 coup d’état against the Liberal president Ramon Villeda Morales and decades-long military rule, rendering the country one of the closest allies of the United States. Military rule and proximity to the United States crushed progressive movements that dared to organize, co-opted the once radical labor movement, and criminalized landless campesinos. In the 1990s, after the peace accords were signed in the Central American region, the Honduran state, following orders by international institutions such as the International Monetary Fund (IMF), implemented neoliberal policies that rolled back many of the hard-fought gains of the 1950s and 1960s by eroding the public sector. As a result of the corroding democratic nature of the neoliberal governments, culminating in the 2009 coup d’état against progressive president Manuel Zelaya, Hondurans from virtually every sector of society, including Indigenous, Black, and feminists, began mobilizing against state policies and demanding a more participatory democracy in La Resistencia, which has transformed into a vibrant, creative, youthful, and widespread movement.
Economy and Society in Southern Portuguese Colonial America
Authors: Kühn Fábio
Published: September 2020

A general overview of the economy and society in the southern part of Portuguese America from the late 17th century to the early 19th century (c. 1680–1820) must address three interconnected areas of colonization: the commercial and military settlement of Colonia de Sacramento, located on the banks of the La Plata River within the borders of modern-day Uruguay, and the captaincies of Santa Catarina and Rio Grande de São Pedro, Brazil. Originally founded as a Portuguese effort to penetrate the mercantile markets of Spanish America, the La Plata settlement was highly disputed until it was definitively conquered by the Spanish in 1777. In contrast, the Portuguese were able to effectively colonize the southern captaincies, which became relatively stable by the end of the 18th century, reflecting the Crown’s relatively successful implementation of a policy of targeted settlement.

The economic formation of the southernmost areas of Portuguese America underwent a change in pattern at the turn of the 19th century. The original economy, centered around the export of livestock, hides, and precious metals, was replaced by a new model based on food production to supply the markets of Brazil’s Southeast and Northeast. At one end of the spectrum lay Colonia de Sacramento, which focused on the smuggling and export of hides; at the other lay Santa Catarina and Rio Grande de São Pedro, linked to the export of manioc flour, dried meat, and wheat to the rest of Brazil.
The Iconographical Falls Efficacy Scale (IconFES) in community-dwelling older people—a longitudinal validation study
Authors: Lim Mei Ling , van Schooten Kimberley S , Radford Kylie A , Menant Jasmine , Lord Stephen R , Sachdev Perminder S , Brodaty Henry , Delbaere Kim
Published: September 2020

Background

This study aimed to develop cut-points for the 30-item and 10-item Iconographical Falls Efficacy Scale (IconFES) in community-dwelling older people and evaluate the psychometric properties, including construct and predictive validity with respect to falls and reduced physical activity over 1 year.

Methods

Eight hundred and one participants completed the IconFES and underwent physical, psychological and cognitive measures at baseline. Physical activity was recorded at baseline and 12 months using an activity monitor, and 1-year fall incidence was collected using monthly falls calendars.

Results

Using receiver-operating characteristic curves and the Youden’s index for history of falls, physiological fall risk and depressive symptoms, cut-points were defined to differentiate between low and high concern about falling (30-item: <53; 10-item: <19). For the 30-item IconFES, we additionally defined cut-points for low (≤40), moderate (41–58) and high (≥59) concern about falling. Groups based on these cut-points differed significantly: low coordinated stability, executive function and amount of daily walking, and high level of disability (30-item version) and female gender (low/high 30-item version). Although there were some inconsistencies across IconFES classifications, high concern about falling predicted having had multiple falls or multiple/injurious falls, low amount of daily walking and low movement intensity at 12 months.

Conclusions

The developed IconFES cut-points were sensitive to variables associated with concern about falling and predicted fall incidence and physical activity restriction after 12 months. Applying these cut-points appears useful to identify older people with high concern about falling, who are at higher risk of falls and activity curtailment.
Neighborhood Deprivation, Obesity, and Diabetes in Residents of the US Gulf Coast
Authors: Hu Michael D , Lawrence Kaitlyn G , Bodkin Mark R , Kwok Richard K , Engel Lawrence S , Sandler Dale P
Published: September 2020

Socioeconomic status has been associated with cardiovascular disease risk factors. However, few studies have examined this relationship among populations in the US Gulf Coast region. We assessed neighborhood deprivation in relation to obesity and diabetes in 9,626 residents participating in the Gulf Long-Term Follow-Up Study (2011–present) who completed a home visit (2011–2013) with height, weight, waist, and hip measurements. Obesity was categorized as body mass index of at least 30, and diabetes was defined by doctor’s diagnosis or prescription medication. Participant home addresses were linked to an established Area Deprivation Index and categorized into 4 levels (1 = least deprived). In adjusted, modified Poisson regression models, participants with greatest deprivation were more likely to have obesity compared with those with least deprivation (adjusted prevalence ratio (aPR) = 1.21, 95% confidence interval (CI): 1.08, 1.35), central obesity (aPR = 1.11, 95% CI: 1.04, 1.19), and diabetes (aPR = 1.49, 95% CI: 1.03, 2.14). Repeated analyses among a subgroup of participants (n = 3,016) whose hemoglobin A1C values were measured 3 years later indicated the association with diabetes (defined as diagnosis, medications, or hemoglobin A1C ≥ 6.5) was similar (aPR = 1.46, 95% CI: 1.14, 1.86). Results suggest neighborhood deprivation is associated with obesity and diabetes in a US region with high baseline prevalence.
Misclassification Error–Adjusted Prevalence of Injection Drug Use Among Infective Endocarditis Hospitalizations in the United States: A Serial Cross-Sectional Analysis of the 2007–2016 National Inpatient Sample
Authors: McGrew Kaitlin M , Garwe Tabitha , Jafarzadeh S Reza , Drevets Douglas A , Zhao Yan Daniel , Williams Mary B , Carabin Hélène
Published: September 2020

Administrative health databases have been used to monitor trends in infective endocarditis hospitalization related to nonprescription injection drug use (IDU) using International Classification of Diseases (ICD) code algorithms. Because no ICD code for IDU exists, drug dependence and hepatitis C virus (HCV) have been used as surrogate measures for IDU, making misclassification error (ME) a threat to the accuracy of existing estimates. In a serial cross-sectional analysis, we compared the unadjusted and ME-adjusted prevalences of IDU among 70,899 unweighted endocarditis hospitalizations in the 2007–2016 National Inpatient Sample. The unadjusted prevalence of IDU was estimated with a drug algorithm, an HCV algorithm, and a combination algorithm (drug and HCV). Bayesian latent class models were used to estimate the median IDU prevalence and 95% Bayesian credible intervals and ICD algorithm sensitivity and specificity. Sex- and age group-stratified IDU prevalences were also estimated. Compared with the misclassification-adjusted prevalence, unadjusted estimates were lower using the drug algorithm and higher using the combination algorithm. The median ME-adjusted IDU prevalence increased from 9.7% (95% Bayesian credible interval (BCI): 6.3, 14.8) in 2008 to 32.5% (95% BCI: 26.5, 38.2) in 2016. Among persons aged 18–34 years, IDU prevalence was higher in females than in males. ME adjustment in ICD-based studies of injection-related endocarditis is recommended.
How Effective Is the Filtration of ‘KN95’ Filtering Facepiece Respirators During the COVID-19 Pandemic?
Authors: Brochot Clothilde , Saidi Mohamed N , Bahloul Ali
Published: September 2020

Objectives

The high demand of filtering facepiece respirators (FFRs) worldwide during the period of the COVID-19 pandemic has led to a critical situation for decision-makers regarding their supply. After authorizing the use of FFRs certified by other regions of the world, decision-makers in many countries have published alerts, particularly concerning the ‘KN95’ type.

Methods

This paper investigated the filtration performance of different FFRs using an experimental setup already employed during several studies on FFRs filtration performance. Its high-resolution measuring devices permit to determine filtration performance according to the normative criteria: the pressure drop and the filtration efficiency. Eight different FFRs have been used: four NIOSH-approved FFRs and four not NIOSH-approved with a ‘KN95’ shape available during the beginning of the COVID-19 pandemic.

Results

The data show a high disparity between different FFRs purchased by healthcare establishments, and between those that are NIOSH-approved and those that are not NIOSH-approved. The results confirm that the NIOSH certification offers good protection according to the normative criteria. The ‘KN95’ types present pressure drops which correspond to the normative value, however their efficiencies are lower than the efficiencies of FFRs certified by NIOSH and lower than 95% at the most penetrate particle size.

Conclusions

FFRs marking is not sufficient to conclude on the FFRs’ efficiency. Visual inspection can not determine which samples are counterfeit or have manufacturing defects.
Symptom Factors and Neuropsychological Performance in Collegiate Athletes with Chronic Concussion Symptoms
Authors: Guty Erin , Riegler Kaitlin , Meyer Jessica , Walter Alexa E , Slobounov Semyon M , Arnett Peter
Published: September 2020

Objective

The present study explored the relationship between specific types of postconcussion symptoms and cognitive outcomes in student–athletes with chronic concussion symptoms.

Method

Forty student–athletes with chronic concussion symptoms were given a battery of neuropsychological tests and rated themselves on a variety of postconcussion symptoms, which included the following factors derived from prior work: Physical, Sleep, Cognitive, Affective, and Headache. Cognitive outcomes included performance on composites for the memory and attention/executive functioning speed tests, respectively. The following covariates were also explored: Sex, depression symptoms, number of previous concussions, and time since injury.

Results

Headache was the only individual symptom factor that significantly (p < .05) predicted worse attention/executive functioning performance. None of the symptom factors were significantly related to memory performance over and above the variable of time since injury, such that longer time since injury was related to worse memory performance.

Conclusion

Comparable to work examining symptom predictors of cognitive outcomes in acutely concussed samples, headache predicted worse attention/executive functioning performance. Additionally, we found that the longer athletes had been symptomatic since injury, the “worse” their memory functioning. Understanding how headache and the length of time an individual is symptomatic are related to cognitive outcomes can help inform treatment and recommendations for athletes with prolonged symptom recovery.
Pathways linking female personality with reproductive success are trait- and year-specific
Authors: Thys Bert , Eens Marcel , Pinxten Rianne , Iserbyt Arne
Published: September 2020

Personality (i.e., among-individual variation in average behavior) often covaries with fitness, but how such personality–fitness relationships come about is poorly understood. Here, we explore potential mechanisms by which two female personality traits (female–female aggression and female nest defense as manifested by hissing behavior) were linked with annual reproductive success in a population of great tits (Parus major), a socially monogamous species with biparental care. We hypothesized that personality-related differences in reproductive success result from variation in reproductive decision (lay date, brood size) and/or parental provisioning rates. Relative support for these mechanisms was evaluated using path analysis on data collected in two successive years. We reveal that larger broods were provisioned at a higher rate by both parents and that female, but not male, provisioning rate was involved in the trade-off between offspring number (brood size) and fledgling mass. Among-individual variation in female aggression, via its association with female provisioning rate, was negatively linked to fledgling mass (i.e., indirect effect), yet only in one of the study years. Male provisioning rate did not influence these relationships. In contrast, among-individual variation in hissing behavior was directly and negatively linked with fledgling mass in both years, via an underlying mechanism that remains to be identified (i.e., direct effect). Together, our findings emphasize that personality–fitness relationships may come about via different mechanisms across personality traits and/or years, thereby illustrating additional complexity in how selection might act on and maintain among-individual variation in behavioral phenotypes in the wild.
dNEMO: a tool for quantification of mRNA and punctate structures in time-lapse images of single cells
Authors: Kowalczyk Gabriel J , Cruz J Agustin , Guo Yue , Zhang Qiuhong , Sauerwald Natalie , Lee Robin E C
Published: September 2020

Motivation

Many biological processes are regulated by single molecules and molecular assemblies within cells that are visible by microscopy as punctate features, often diffraction limited. Here, we present detecting-NEMO (dNEMO), a computational tool optimized for accurate and rapid measurement of fluorescent puncta in fixed-cell and time-lapse images.

Results

The spot detection algorithm uses the à trous wavelet transform, a computationally inexpensive method that is robust to imaging noise. By combining automated with manual spot curation in the user interface, fluorescent puncta can be carefully selected and measured against their local background to extract high-quality single-cell data. Integrated into the workflow are segmentation and spot-inspection tools that enable almost real-time interaction with images without time consuming pre-processing steps. Although the software is agnostic to the type of puncta imaged, we demonstrate dNEMO using smFISH to measure transcript numbers in single cells in addition to the transient formation of IKK/NEMO puncta from time-lapse images of cells exposed to inflammatory stimuli. We conclude that dNEMO is an ideal user interface for rapid and accurate measurement of fluorescent molecular assemblies in biological imaging data.

Availability and implementation

The data and software are freely available online at https://github.com/recleelab.

Supplementary information

Supplementary data are available at Bioinformatics online.
An efficient and robust approach to Mendelian randomization with measured pleiotropic effects in a high-dimensional setting
Authors: Grant Andrew J , Burgess Stephen
Published: September 2020

Valid estimation of a causal effect using instrumental variables requires that all of the instruments are independent of the outcome conditional on the risk factor of interest and any confounders. In Mendelian randomization studies with large numbers of genetic variants used as instruments, it is unlikely that this condition will be met. Any given genetic variant could be associated with a large number of traits, all of which represent potential pathways to the outcome which bypass the risk factor of interest. Such pleiotropy can be accounted for using standard multivariable Mendelian randomization with all possible pleiotropic traits included as covariates. However, the estimator obtained in this way will be inefficient if some of the covariates do not truly sit on pleiotropic pathways to the outcome. We present a method that uses regularization to identify which out of a set of potential covariates need to be accounted for in a Mendelian randomization analysis in order to produce an efficient and robust estimator of a causal effect. The method can be used in the case where individual-level data are not available and the analysis must rely on summary-level data only. It can be used where there are any number of potential pleiotropic covariates up to the number of genetic variants less one. We show the results of simulation studies that demonstrate the performance of the proposed regularization method in realistic settings. We also illustrate the method in an applied example which looks at the causal effect of urate plasma concentration on coronary heart disease.
Social Exclusion, Resilience and Social Worker Preparedness: Providing Services to Gay and Bisexual Men Who Party-n-Play
Authors: Souleymanov Rusty , Brennan David J , Logie Carmen H , Allman Dan , Craig Shelley L , Halkitis Perry N
Published: September 2020

Party-n-Play (PNP) refers to sex between gay and bisexual men that occurs under the influence of drugs. Growing evidence suggests gay and bisexual men who PNP experience significant stigma and social exclusion. Less is known about the resilience of this population. Utilising critical discourse analysis, this study examined how gay and bisexual men who PNP talk about social exclusion and resilience in their lives. In-depth one-hour interviews were conducted with forty-four gay and bisexual men who lived in Toronto, and who used various drugs before or during sex with another man in the previous month. Study findings revealed that social exclusion was perpetuated through discourses of stigma, deviance, morality, heteronormativity, homophobia, racism, classism, risk and policing. These discourses also negatively affected participants’ interactions with health care providers. However, many participants evoked resilience discourses and described social bonds, friendships and relations of care in their networks. Social work professionals would benefit from examining the roles of social exclusion, as well as stigmatising and pathologising discourses in their practice. These findings also underscore the need for culturally sensitive social work interventions for this population that address social exclusion and foster resilience.
Unexpected Sounds Nonselectively Inhibit Active Visual Stimulus Representations
Authors: Soh Cheol , Wessel Jan R
Published: September 2020

The brain’s capacity to process unexpected events is key to cognitive flexibility. The most well-known effect of unexpected events is the interruption of attentional engagement (distraction). We tested whether unexpected events interrupt attentional representations by activating a neural mechanism for inhibitory control. This mechanism is most well characterized within the motor system. However, recent work showed that it is automatically activated by unexpected events and can explain some of their nonmotor effects (e.g., on working memory representations). Here, human participants attended to lateralized flickering visual stimuli, producing steady-state visual evoked potentials (SSVEPs) in the scalp electroencephalogram. After unexpected sounds, the SSVEP was rapidly suppressed. Using a functional localizer (stop-signal) task and independent component analysis, we then identified a fronto-central EEG source whose activity indexes inhibitory motor control. Unexpected sounds in the SSVEP task also activated this source. Using single-trial analyses, we found that subcomponents of this source differentially relate to sound-induced SSVEP changes: While its N2 component predicted the subsequent suppression of the attended-stimulus SSVEP, the P3 component predicted the suppression of the SSVEP to the unattended stimulus. These results shed new light on the processes underlying fronto-central control signals and have implications for phenomena such as distraction and the attentional blink.
Individual and Composite Adverse Pregnancy Outcomes in a Randomized Trial on Isoniazid Preventative Therapy Among Women Living With Human Immunodeficiency Virus
Authors: Theron Gerhard , Montepiedra Grace , Aaron Lisa , McCarthy Katie , Chakhtoura Nahida , Jean-Philippe Patrick , Zimmer Bonnie , Loftis Amy James , Chipato Tsungai , Nematadzira Teacler , Nyati Mandisa , Onyango-Makumbi Carolyne , Masheto Gaerolwe , Ngocho James , Tongprasert Fuanglada , Patil Sandesh , Lespinasse Dominique , Weinberg Adriana , Gupta Amita
Published: September 2020

Background

International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) P1078, a randomized noninferiority study designed to compare the safety of starting isoniazid preventive therapy (IPT) in women living with human immunodeficiency virus (HIV) either during pregnancy or after delivery, showed that IPT during pregnancy increased the risk of composite adverse pregnancy outcomes, but not individual outcomes. Many known factors are associated with adverse pregnancy outcomes: these factors’ associations and effect modifications with IPT and pregnancy outcomes were examined.

Methods

Pregnant women living with HIV from 8 countries with tuberculosis incidences >60/100 000 were randomly assigned to initiate 28 weeks of IPT either during pregnancy or at 12 weeks after delivery. Using univariable and multivariable logistic regression and adjusting for factors associated with pregnancy outcomes, composite and individual adverse pregnancy outcome measures were analyzed.

Results

This secondary analysis included 925 mother-infant pairs. All mothers were receiving antiretrovirals. The adjusted odds of fetal demise, preterm delivery (PTD), low birth weight (LBW), or a congenital anomaly (composite outcome 1) were 1.63 times higher among women on immediate compared to deferred IPT (95% confidence interval [CI], 1.15–2.31). The odds of fetal demise, PTD, LBW, or neonatal death within 28 days (composite outcome 2) were 1.62 times higher among women on immediate IPT (95% CI, 1.14–2.30). The odds of early neonatal death within 7 days, fetal demise, PTD, or LBW (composite outcome 3) were 1.74 times higher among women on immediate IPT (95% CI, 1.22–2.49).

Conclusions

We confirmed higher risks of adverse pregnancy outcomes associated with the initiation of IPT during pregnancy, after adjusting for known risk factors for adverse pregnancy outcomes.
Graph fractal dimension and the structure of fractal networks
Authors: Skums Pavel , Bunimovich Leonid
Published: September 2020

Fractals are geometric objects that are self-similar at different scales and whose geometric dimensions differ from so-called fractal dimensions. Fractals describe complex continuous structures in nature. Although indications of self-similarity and fractality of complex networks has been previously observed, it is challenging to adapt the machinery from the theory of fractality of continuous objects to discrete objects such as networks. In this article, we identify and study fractal networks using the innate methods of graph theory and combinatorics. We establish analogues of topological (Lebesgue) and fractal (Hausdorff) dimensions for graphs and demonstrate that they are naturally related to known graph-theoretical characteristics: rank dimension and product dimension. Our approach reveals how self-similarity and fractality of a network are defined by a pattern of overlaps between densely connected network communities. It allows us to identify fractal graphs, explore the relations between graph fractality, graph colourings and graph descriptive complexity, and analyse the fractality of several classes of graphs and network models, as well as of a number of real-life networks. We demonstrate the application of our framework in evolutionary biology and virology by analysing networks of viral strains sampled at different stages of evolution inside their hosts. Our methodology revealed gradual self-organization of intra-host viral populations over the course of infection and their adaptation to the host environment. The obtained results lay a foundation for studying fractal properties of complex networks using combinatorial methods and algorithms.