Browse Articles

Role of leaders’ positive mindset in mitigating the effects of crises on organizations: The case of Canadian organizations

Maintaining a positive mindset is important for leadership effectiveness and may even be more important in times of a crisis because such a mindset contributes to organizational survival and resilience. In this study, we examined whether leaders’ positive mindset helped to mitigate the harmful effects of the COVID-19 crisis on organizations and if so, how. To address this issue, we conducted an empirical study through LinkedIn with 165 participants working in various organizations in Canada. The results show that leaders’ positive mindset positively impacts leaders’ innovative behavior. However, leaders’ innovative behavior did not attenuate the negative effects of the COVID-19 crisis on organizations, except when we introduce the use of information and communication technology (ICT) and the provision of psychological support to employees as moderators. The implications of these findings for both theory and practice, as well as some future research directions are discussed.

The chain mediating effect of emotional regulation ability and exercise persistence on college students’ sleep and cardiopulmonary endurance

Rippled shock propagation in a laser-driven target at multimegabar pressures

The evolution of non-uniform shocks produced by modulated laser irradiation or surface perturbations is relevant to studies of inertial confinement fusion and material properties at high-energy-density conditions. We present results from an experiment conducted at the OMEGA EP laser facility, where a 300 GPa shock was driven into a fused silica sample with pre-fabricated single-mode surface modulations. Using time-resolved optical velocimetry, we captured the continuous evolution of rippled shock motion, enabling a comprehensive mapping of the spatial amplitude history from formation to phase reversal in a single experiment. Initially, the ablation-driven shock inherits a fraction of the surface modulation amplitude from the sample, which subsequently grows before decaying, ultimately leading to the flattening of the rippled shock and a phase reversal. We find that two-dimensional inviscid hydrodynamic simulation of the experiment is able to qualitatively capture many aspects of the rippled shock evolution but over-predicts the initial amplitude growth. This experimental platform, capable of accommodating varying ripple wavelengths, lays the groundwork for a potential viscometry method at extreme pressures, where viscous effects manifest as differences in shock flattening times between rippled shocks of two distinct wavelengths propagating through the sample.

Non-perturbative exciton transfer rate analysis of the Fenna–Matthews–Olson photosynthetic complex under reducing and oxidizing conditions

Two-dimensional optical spectroscopy experiments have examined photoprotective mechanisms in the Fenna–Matthews–Olson (FMO) photosynthetic complex, showing that exciton transfer pathways change significantly depending on the environmental redox conditions. Higgins et al. [Proc. Natl. Acad. Sci. U. S. A. 118(11), e2018240118 (2021)] have theoretically linked these observations to changes in a quantum vibronic coupling, whereby onsite energies are altered under oxidizing conditions such that exciton energy gaps are detuned from a specific vibrational motion of the bacteriochlorophyll a. These arguments rely on an analysis of exciton transfer rates within Redfield theory, which is known to provide an inaccurate description of the influence of the vibrational environment on the exciton dynamics in the FMO complex. Here, we use a memory kernel formulation of the hierarchical equations of motion to obtain non-perturbative estimations of exciton transfer rates, which yield a modified physical picture. Our findings indicate that onsite energy shifts alone do not reproduce the reported rate changes in the oxidative environment. We systematically examine a model that includes combined changes in both site energies and the frequency of a local vibration in the oxidized complex while maintaining consistency with absorption spectra and achieving qualitative, but not quantitative, agreement with the measured changes in transfer rates. Our analysis points to potential limitations of the FMO electronic Hamiltonian, which was originally derived by fitting spectra to perturbative theories. Overall, our work suggests that further experimental and theoretical analyses may be needed to understand the variations of exciton dynamics under different redox conditions.

Noteworthy trends in maladaptive coping strategies and hindrances to help-seeking behaviour among adolescents living in Malaysia’s People’s Housing Project (PPR) during the COVID-19 pandemic: A qualitative study

Background COVID-19 has greatly affected the population, especially those in the low socio-economic group, including residents of the People’s Housing Project (PPR) in Malaysia. Adolescents residing in PPR communities are among the most vulnerable groups of young people in urban areas, given their pre-existing conditions of vulnerability, face even greater challenges due to the pandemic. Understanding their mental health and coping strategies is vital to grasp how the pandemic impacts their well-being. Hence, this study aims to explore the coping strategies and barriers to help-seeking behaviour among adolescents living in the Malaysia’s PPR communities, focusing on the unique mental health challenges exacerbated by the COVID-19 pandemic. Given the socio-economic vulnerabilities and the heightened mental health challenges during the pandemic, this study provides critical insights into how adolescents in PPR communities navigate psychological distress and mental health support. Methods This qualitative study used a phenomenological research design and was conducted from January to December 2022, involving 47 adolescents aged 10 to 17 years old from 37 PPRs in the Klang Valley. Participants were recruited using the purposive sampling method as this study purposely selected adolescents with moderate, moderately severe, and severe for PHQ-9 and/or moderate and severe for GAD-7 based on the screening. Participants who agreed to participate were recruited (with consent from parents/guardians) and interviews were set at the participants’ convenience. Data were collected using a semi-structured interview guide to conduct the in-depth interviews (IDI). After each IDI session, the recorded interviews were transcribed. Data from the voice recorder were stored on a password-protected computer, and participants’ names were replaced with specific codes to ensure confidentiality. The researchers coded all transcripts independently. The transcripts were analysed inductively using a thematic approach to identify recurring themes. Results From the 37 PPRs, 194 adolescents were identified as having psychological distress based on the screening. Among them, 47 agreed to participate in the IDIs, which revealed that these adolescents utilized mainly maladaptive coping strategies, such as avoidance (cognitive distancing, externalization, and internalization), self-harm, vaping, and smoking to deal with stressors related to COVID-19. As for hindrances to help-seeking, three themes were identified such as lack of trust, perceived ineffectiveness of support, and personality. Conclusion Psychological distress among adolescents was prevalent during the pandemic, and they faced hindrances in seeking help. Coping strategies have been identified to help adolescents manage their psychological distress during the pandemic. It is concerning that some had resorted to maladaptive coping mechanisms. These findings emphasized the need for targeted mental health interventions and support systems tailored to vulnerable communities. These interventions could inform policies aimed at strengthening mental health services, fostering better coping strategies and promoting help-seeking behaviours among adolescents in socio-economically challenged communities.

Association between body roundness index and weight-adjusted waist index with asthma prevalence among US adults: the NHANES cross-sectional study, 2005–2018

Thermal equations of state of B2-structured rubidium halides RbCl, RbBr, and RbI

In this study, we determined the thermal equations of state (EoS) for rubidium chloride (RbCl), rubidium bromide (RbBr), and rubidium iodide (RbI) in the B2 (CsCl-type) structure. We conducted in situ energy-dispersive x-ray diffraction measurements at high pressures (up to 26 GPa) and temperatures (up to 1800 K) using a large volume press. Pressures were calibrated using CsCl, Mo, and Pt in the same cell assemblies. For each B2-structured Rb halide, the parameter V0 (unit cell volume at room pressure) was estimated from additional diamond anvil cell experiments at 300 K. Using the third-order Birch–Murnaghan equation and the Mie–Grüneisen–Debye thermal model, we derived the thermoelastic parameters for each phase: RbCl: K0 = 19.89(8) GPa, K0′ = 5.00(2), γ0 = 1.96(4), q = 1.05(9), RbBr: K0 = 16.28(4) GPa, K0′ = 5.28(2), γ0 = 2.18(14), q = 1.52(24), RbI: K0 = 13.69(4) GPa, K0′ = 4.95(1), γ0 = 2.21(7), q = 1.42(10). These parameters represent the isothermal bulk modulus (K0), its pressure derivative (K0′), the Grüneisen parameter (γ0), and the logarithmic volume dependence of the Grüneisen parameter (q). The newly derived EoS for rubidium halides provides effective pressure markers above 0.5 GPa, as they remain stable across wide pressure and temperature ranges. Additionally, RbCl and RbBr offer improved x-ray transmission compared to CsCl. These EoS can be combined with a secondary metallic phase to estimate pressure and temperature in the absence of a thermocouple, taking advantage of the large differences in thermal expansion between halides and metals.

How accurate are lattice models with Gaussian energy disorder in describing charge-carrier transport and reactions in amorphous organic semiconductors?

We model charge-carrier hopping transport and electron–hole recombination in realistic amorphous structures of different densities and use the obtained results to assess the quality of the lattice models with Gaussian energy disorder, which have been the main theoretical tool in the studies of amorphous organic semiconductors. We find that the hopping-site energy distributions inferred from the amorphous structures deviate from the Gaussian distribution, especially in their low-energy tails. Mostly for this reason, the effect of disorder on charge-carrier mobility is much weaker than predicted by the lattice/Gaussian models and dependent on system density. The lattice models of electron–hole recombination in disordered systems, which assume a Gaussian site energy distribution, are found to be more accurate than those of charge-carrier transport. This is explained by the strong Coulomb trapping of electron–hole pairs before recombination, which makes the role of hopping-site energy disorder less significant.

Does the urban low-carbon transition promote the residents’ health consumption?

This work employs a fixed-effects model to analyze the influence of urban low-carbon transition on residents’ health consumption, utilizing data from the China General Social Survey (CGSS) for the years 2018 and 2021. The model estimation value is 0.1349, significant at the 5% confidence range, demonstrating that urban low-carbon transition enhances residents’ health consumption. This result successfully underwent both the robustness test and the endogeneity test. The mechanism test reveals that urban low-carbon transition influences residents’ health consumption through two pathways: increasing health awareness and improving the level of habitat environment. The heterogeneity studies indicate that the impact of the urban low-carbon transition on residents’ health consumption varies according to income levels, gender, and urban development stages. Higher-income people, female residents, and those in locations with advanced urban development significantly contribute to this influence. The study ultimately presents pertinent policy proposals aimed at enhancing the urban low-carbon transition, increasing the residents’ understanding of health consumption, improving the level of habitat environment, and paying attention to coordinated and healthy development.

Adults are just as susceptible to memory suggestibility when reporting about single and repeated events

Metal free all oxide SnOx/HfOx bilayer transristor synapse for neuromorphic computing

Developing flexible and transparent memristors for emulating biological activities aligns with the growing demand for sustainable technologies in electronics. This paper presents the development and characterization of transparent memristors (transristors) on a flexible substrate, utilizing a structure of ITO/SnOx/HfOx/ITO/PEN. Hafnium oxide (HfOx) and tin oxide (SnOx) films are sequentially RF sputtered onto an indium doped tin oxide (ITO) bottom electrode, with polyethylene naphthalate serving as the flexible substrate. Then, an ITO top electrode is sputtered onto the SnOx layer using a shadow mask. Samples with varying thicknesses of HfOx and SnOx were prepared to optimize the device configuration. Electrical switching and synaptic characteristics of these samples were measured at room temperature, with a positive voltage applied to the top electrode and a negative voltage to the bottom electrode. This study identifies a configuration with 35 nm SnOx and 6 nm HfOx as the most effective, exhibiting excellent bipolar switching properties. Notably, it demonstrates low set/reset voltages of 1.3 and −1.6 V, with a compliance current of 100 μA. X-ray photoelectron spectroscopy was employed to assess the concentration of oxygen vacancies in the films. The device also shows the highest endurance up to 104 cycles, long-term potentiation/depression characteristics over 350 cycles, a good nonlinearity value of 1.53 (potentiation)/1.46 (depression), and 100% pattern recognition accuracy at just 14 iterations. Multi-state resistive switching characteristics were also explored. Obtained characteristics reveal that the optimized device could serve as a flexible component in making artificial synapses.

Protein solvation: Site-specific hydrophilicity, hydrophobicity, counter ions, and interaction entropy

Solvation free energy is a driving force that plays an important role in the stability of biomolecular conformations. Currently, the implicit solvent model is widely used to calculate solvation energies of biomolecules such as proteins. However, for proteins, the implicit solvent calculation does not provide much detailed information since a protein is highly inhomogeneous on its surface. In this study, we develop an explicit solvent approach to protein solvation, which allows us to investigate detailed site-specific hydrophilicity and hydrophobicity, including the role of counter ions and intra-protein interactions. This approach facilitates the analysis of specific residue interactions with solvent molecules, extending the understanding of protein solubility to the energetic impacts of site-specific residue–solvent interactions. Our study showed that specific residue–solvent interactions are strongly influenced by the electrostatic environment created by its nearby residues, especially charged residues. In particular, charged residues on the protein surface are mainly responsible for the heterogeneity of the electrostatic environment of the protein surface, and they significantly affect the local distribution of water. In addition, counter ions change the local electrostatic environment and alter specific residue–water interactions. Neutral residues also interact with water, with polar residues being more prominent than nonpolar ones but contributing less to solvation energy than charged residues. This study illustrates an explicit solvent approach to protein solvation, which gives residue-specific contributions to protein solvation and provides detailed information on site-specific hydrophilicity and hydrophobicity.

Feeding habit and diet composition of three fish species inhabiting Sor River, Baro-Akobo Basin of Ethiopia, East Africa

The purpose of this study was to investigate feeding habit and diet composition of three fish species (Oreochromis niloticus, Labeo forskalii and Labeobarbus intermedius ) inhabiting Sor River, Baro-Akobo basin of Ethiopia. Stomach contents of these fish species were examined. A total of 73 fish gut samples were collected from fishermen on site from February to March 2022. The diet composition of each species was analysed and expressed as percentage of frequency of occurrence (% F), numerical occurrence and gravimetric composition (% G). The major food items in the stomach of each species were determined using percentage index of relative importance (% IRI). The study showed that O. niloticus from Sor River feeds on phytoplankton, macrophytes and detritus as major prey. The stomach of L. forskalii was found to have Phytoplankton, macrophytes, insects, fish larvae, detritus and others. The gut content analysis of L. intermedius revealed phytoplankton and detritus found to be the dominant food constituents with % IRI 23.72% and 28.04% respectively. Fish larvae and flatworms are important diet constituents. The diet breadth index which measures the diversity of prey items consumed by each fish species was 0.43 for O. niloticus, 0.61 for L. intermedius and 0.64 for L. forskalii, respectively. According to their diet breadth and overlap indices, the three fish species had an omnivorous feeding habit which is useful to enhance fisheries and aquaculture development in the study area.

Group verifiable secure aggregate federated learning based on secret sharing

Phonon dispersion filter: A physics-inspired feature selection for machine learning potentials

How to improve the accuracy and precision of machine learning potential functions while reducing their computational cost has long been a subject of considerable interest. In this regard, a common approach is to reduce the number of descriptors through feature selection and dimensionality reduction, thereby improving computational efficiency. In our paper, we propose a descriptor selection method based on the material’s phonon spectrum, which is called a phonon dispersion filter (PDF) method. Compared to other mathematics-based machine learning feature selection methods, the PDF method is a more physics-based feature selection approach. Taking graphene and bulk silicon as examples, we provide a detailed introduction to the screening process of the PDF method and its underlying principles. Furthermore, we test the PDF method on two types of descriptors: Atom-centered symmetry functions descriptors and smooth overlap of atomic positions descriptors. Both demonstrate promising screening results.

Strong coupling non-Markovian quantum thermodynamics of a finite-bath system

The focus is on understanding the quantum thermodynamics of strongly coupled non-Markovian quantum systems. To this end, a non-trivial, non-Markovian model of a central spin surrounded by a spin bath is taken up, and its exact evolution is derived for arbitrary system-bath couplings. The fundamental quantum thermodynamic quantities, such as system and bath internal energies, work, heat, entropy production, and ergotropy, are calculated using the dynamics and the original system (bath) Hamiltonian. An explicit expression for the work, a mismatch between the system and bath internal energies, is derived. The thermodynamic entropy of the system at thermal equilibrium is studied using the Hamiltonian of mean force in the strong coupling regime. The role of a canonical Hamiltonian in calculating the above thermodynamic quantities, a recently developed technique, is also investigated. Furthermore, an interesting observation relevant to the spin bath acting as a charger is made in a scenario where the central spin is envisaged as a quantum battery.

Fine scale mapping of water sources in low-income settings: A comparative study in Misungwi, Tanzania

Access to safe water, sanitation, and hygiene is a basic human need for health and well-being. Yet, 2.2 billion people globally in 2022 did not have access to safely managed drinking water. Presently there are no publicly available methods for monitoring and measuring access to water sources in low-income settings at a fine spatial scale. The objective of this study was to map and identify areas with improved and unimproved water points in Misungwi, Tanzania using two different methods: 1) community mapping with direct field observations, and 2) drone imagery. We quantified and summarized the number of improved and unimproved water sources, as defined by the WHO/UNICEF Joint Monitoring Programme core questions and noted their specific uses where applicable. We also compared the results of both data collection methods outlining their respective advantages and limitations. The community maps and direct field observations not only served as a method to identify water sources, but also provided insights into how community members used and interacted with each water source. In contrast, the drone imagery only served as a method to systematically identify water sources in the study area. A notable advantage of the drone imagery, however, was its ability to identify more unimproved water sources (225 vs 90) compared to the direct field observations. Both methods were effective in identifying water sources at a fine scale, but the drone imagery involved a more time-intensive process, demanded advanced skills, and incurred a higher cost compared to the community mapping with direct field observations. This study highlights the need for accurate and readily accessible data on water sources which is imperative for planning, developing, and managing improved water sources, especially in underserved areas such as Misungwi, Tanzania.

Determination of both the expression and serum levels of epidermal growth factor and transforming growth factor β1 genes in COVID-19

Local structure of zinc–indium–tin oxide films via grazing-incidence x-ray pair-distribution functions and theoretical methods

A detailed experimental and theoretical study on the local (r ≤ 4.5 Å) atomic structure of amorphous and crystalline zinc–indium–tin oxide (ZITO) thin films using grazing-incidence x-ray Pair-Distribution Functions (PDFs), ab initio Molecular Dynamics (MD), and Empirical Potential Structure Refinement (EPSR) Monte Carlo simulations is presented. High-energy synchrotron x rays, a two-dimensional detector, and different incident angles were used to probe the depth uniformity of five (ZnO)0.15 (In2O3)0.70 (SnO2)0.15 films that were deposited via pulsed-laser deposition at growth temperatures (TG) ranging from 25 to 300 °C. Films deposited at TG ≤ 150 °C were amorphous. The partially crystalline (TG = 200 °C) and fully crystalline (TG = 300 °C) films were highly textured. Both crystalline and amorphous structures were investigated using ab initio MD and EPSR Monte Carlo simulations. The density of the amorphous films determined from the experimental data agreed with MD calculations. Coordination numbers, bond lengths, and distortion for metal–oxygen and for both the edge- and corner-shared In–metal shells up to 4.5 Å obtained from PDF analysis closely agreed with MD and EPSR simulations. There is a pronounced decrease in the edge- and corner-shared In–Zn distances arising from the shorter Zn–O bond length, Zn–O tetrahedral coordination, and In–O–Zn angle in amorphous ZITO compared to its crystalline counterpart. A maximum in electrical mobility was observed for the amorphous film just before crystallization occurred. While the peak is broad, consistent with nearly unchanged overall cation–oxygen coordination in the amorphous films, ESPR results indicate that the tetrahedral coordination follows the conductivity trend.

Spin migration in density functional theory: Energy, potential, and density perspectives

Spin is a fundamental property of any many-electron system. The ability of density functional theory to accurately predict the physical properties of a system, while varying its spin, is crucial for describing magnetic materials and high-spin molecules, spin flips, and magnetization and demagnetization processes. Within density functional theory, when using various exchange–correlation approximations, the exact dependence of the energy on the spin often deviates from the exact constant or piecewise-linear behavior, which is directly related to the problem of strong (static) correlation and challenges the description of molecular dissociation. In this paper, we study the behavior of the energy, the frontier Kohn–Sham (KS) and generalized KS (GKS) orbitals, the KS potentials, and the electron density, with respect to fractional spin, in different atomic systems. We analyze seven standard exchange–correlation functionals and find two main scenarios of deviation from the expected exact results. We clearly recognize a jump in the frontier orbital energies upon spin variation in the exact exchange and in hybrid functionals, as well as the related plateau in the corresponding KS potential, when using the optimized effective potential method within the KS scheme. When calculations are performed using the GKS approach, no jumps are observed, as expected. Moreover, we demonstrate that for high-spin systems, a full three-dimensional treatment is crucial; the spherical approximation commonly used in atoms causes a qualitative deviation. Our results are instrumental for the assessment of the quality of existing approximations from a new perspective and for the development of advanced functionals with sensitivity to magnetic properties.