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Showing papers by "University of Arkansas published in 2020"


Journal ArticleDOI
TL;DR: Results indicate that isolation is a necessary measure to protect public health, but results indicate that it alters physical activity and eating behaviours in a health compromising direction.
Abstract: Background: Public health recommendations and governmental measures during the COVID-19 pandemic have resulted in numerous restrictions on daily living including social distancing, isolation and home confinement. While these measures are imperative to abate the spreading of COVID-19, the impact of these restrictions on health behaviours and lifestyles at home is undefined. Therefore, an international online survey was launched in April 2020, in seven languages, to elucidate the behavioural and lifestyle consequences of COVID-19 restrictions. This report presents the results from the first thousand responders on physical activity (PA) and nutrition behaviours. Methods: Following a structured review of the literature, the “Effects of home Confinement on multiple Lifestyle Behaviours during the COVID-19 outbreak (ECLB-COVID19)” Electronic survey was designed by a steering group of multidisciplinary scientists and academics. The survey was uploaded and shared on the Google online survey platform. Thirty-five research organisations from Europe, North-Africa, Western Asia and the Americas promoted the survey in English, German, French, Arabic, Spanish, Portuguese and Slovenian languages. Questions were presented in a differential format, with questions related to responses “before” and “during” confinement conditions. Results: 1047 replies (54% women) from Asia (36%), Africa (40%), Europe (21%) and other (3%) were included in the analysis. The COVID-19 home confinement had a negative effect on all PA intensity levels (vigorous, moderate, walking and overall). Additionally, daily sitting time increased from 5 to 8 h per day. Food consumption and meal patterns (the type of food, eating out of control, snacks between meals, number of main meals) were more unhealthy during confinement, with only alcohol binge drinking decreasing significantly. Conclusion: While isolation is a necessary measure to protect public health, results indicate that it alters physical activity and eating behaviours in a health compromising direction. A more detailed analysis of survey data will allow for a segregation of these responses in different age groups, countries and other subgroups, which will help develop interventions to mitigate the negative lifestyle behaviours that have manifested during the COVID-19 confinement.

1,275 citations


Journal ArticleDOI
TL;DR: Fear appears to be concentrated in regions with the highest reported COVID-19 cases, and significant bivariate relationships were found between socially vulnerable respondents and fear, as well as with mental health consequences (anxiety and depressive symptoms).
Abstract: The intent of this work was to examine the intersection of COVID-19 fear with social vulnerabilities and mental health consequences among adults living in the United States. Data are from a nationally representative sample (n = 10,368) of U.S. adults surveyed online during demographic subgroups (gender, age, income, race and ethnicity, geography). The sample week of March 23, 2020. The sample was poststratification weighted to ensure a balanced representation across social and demographic subgroups (gender, age, income, race or ethnicity, geography). The sample comprised 51% female; 23% non-White; 18% Hispanic; 25% of households with children under 18 years of age; 55% unmarried; and nearly 20% unemployed, laid off, or furloughed at the time of the interview. Respondents were fearful, averaging a score of nearly 7 on a scale of 10 when asked how fearful they were of COVID-19. Preliminary analysis suggests clear spatial diffusion of COVID-19 fear. Fear appears to be concentrated in regions with the highest reported COVID-19 cases. Significant differences across several U.S. census regions are noted (p < .01). Additionally, significant bivariate relationships were found between socially vulnerable respondents (female, Asians, Hispanic, foreign-born, families with children) and fear, as well as with mental health consequences (anxiety and depressive symptoms). Depressive symptoms, on average, were high (16+ on the Center for Epidemiologic Studies Depression scale), and more than 25% of the sample reported moderate to severe anxiety symptoms. More in-depth psychosocial research is needed using nationally representative samples that can help to inform potential mental health risks, as well as by targeting specific mental health interventions. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

386 citations


Journal ArticleDOI
TL;DR: This article provides an outline of the classification of the kingdom Fungi (including fossil fungi), and treats 19 phyla of fungi, including all currently described orders of fungi.
Abstract: This article provides an outline of the classification of the kingdom Fungi (including fossil fungi. i.e. dispersed spores, mycelia, sporophores, mycorrhizas). We treat 19 phyla of fungi. These are Aphelidiomycota, Ascomycota, Basidiobolomycota, Basidiomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Entorrhizomycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. The placement of all fungal genera is provided at the class-, order- and family-level. The described number of species per genus is also given. Notes are provided of taxa for which recent changes or disagreements have been presented. Fungus-like taxa that were traditionally treated as fungi are also incorporated in this outline (i.e. Eumycetozoa, Dictyosteliomycetes, Ceratiomyxomycetes and Myxomycetes). Four new taxa are introduced: Amblyosporida ord. nov. Neopereziida ord. nov. and Ovavesiculida ord. nov. in Rozellomycota, and Protosporangiaceae fam. nov. in Dictyosteliomycetes. Two different classifications (in outline section and in discussion) are provided for Glomeromycota and Leotiomycetes based on recent studies. The phylogenetic reconstruction of a four-gene dataset (18S and 28S rRNA, RPB1, RPB2) of 433 taxa is presented, including all currently described orders of fungi.

381 citations


Journal ArticleDOI
TL;DR: This review focuses on the recent progress on the stabilization of LMA with nonaqueous electrolytes and reveals the fundamental mechanisms behind this improved stability, which will lead to the large-scale application of LMBs.
Abstract: High-energy rechargeable lithium (Li) metal batteries (LMBs) with Li metal anode (LMA) were first developed in the 1970s, but their practical applications have been hindered by the safety and low-efficiency concerns related to LMA. Recently, a worldwide effort on LMA-based rechargeable LMBs has been revived to replace graphite-based, Li-ion batteries because of the much higher energy density that can be achieved with LMBs. This review focuses on the recent progress on the stabilization of LMA with nonaqueous electrolytes and reveals the fundamental mechanisms behind this improved stability. Various strategies that can enhance the stability of LMA in practical conditions and perspectives on the future development of LMA are also discussed. These strategies include the use of novel electrolytes such as superconcentrated electrolytes, localized high-concentration electrolytes, and highly fluorinated electrolytes, surface coatings that can form a solid electrolyte interphase with a high interfacial energy and self-healing capabilities, development of "anode-free" Li batteries to minimize the interaction between LMA and electrolyte, approaches to enable operation of LMA in practical conditions, etc. Combination of these strategies ultimately will lead us closer to the large-scale application of LMBs which often is called the "Holy Grail" of energy storage systems.

293 citations


Journal ArticleDOI
TL;DR: The preliminary findings elucidate the risk of psychosocial strain during the early COVID-19 home confinement period in 2020 and suggest implementation of national strategies focused on promoting social inclusion through a technology-based solution is strongly suggested.
Abstract: Public health recommendations and governmental measures during the new coronavirus disease (COVID-19) pandemic have enforced numerous restrictions on daily living including social distancing, isolation, and home confinement. While these measures are imperative to mitigate spreading of COVID-19, the impact of these restrictions on psychosocial health is undefined. Therefore, an international online survey was launched in April 2020 to elucidate the behavioral and lifestyle consequences of COVID-19 restrictions. This report presents the preliminary results from more than one thousand responders on social participation and life satisfaction. Methods: Thirty-five research organizations from Europe, North-Africa, Western Asia, and the Americas promoted the survey through their networks to the general society, in 7 languages (English, German, French, Arabic, Spanish, Portuguese, and Slovenian). Questions were presented in a differential format with questions related to responses “before” and “during” confinement conditions. Results: 1047 participations (54% women) from Asia (36%), Africa (40%), Europe (21%), and others (3%) were included in the analysis. Findings revealed psychosocial strain during the enforced COVID-19 home confinement. Large decreases (p < 0.001) in the amount of social activity through family (−58%), friends/neighbors (−44.9%), or entertainment (−46.7%) were triggered by the enforced confinement. These negative effects on social participation were also associated with lower life satisfaction (−30.5%) during the confinement period. Conversely, the social contact score through digital technologies significantly increased (p < 0.001) during the confinement period with more individuals (+24.8%) being socially connected through digital technology. Conclusion: These preliminary findings elucidate the risk of psychosocial strain during the early COVID-19 home confinement period in 2020. Therefore, in order to mitigate the negative psychosocial effects of home confinement, implementation of national strategies focused on promoting social inclusion through a technology-based solution is strongly suggested.

284 citations


Journal ArticleDOI
TL;DR: The authors report the formation of skyrmion lattice in the WTe2/Fe3GeTe2 van der Waals heterostructure and a Dzyaloshinskii–Moriya interaction with a large energy density of 1.0 mJm−2.
Abstract: The promise of high-density and low-energy-consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. At the same time, recently discovered long-range intrinsic magnetic orders in the two-dimensional van der Waals materials provide a new platform for the discovery of novel physics and effects. Here we demonstrate the Dzyaloshinskii-Moriya interaction and Neel-type skyrmions are induced at the WTe2/Fe3GeTe2 interface. Transport measurements show the topological Hall effect in this heterostructure for temperatures below 100 K. Furthermore, Lorentz transmission electron microscopy is used to directly image Neel-type skyrmion lattice and the stripe-like magnetic domain structures as well. The interfacial coupling induced Dzyaloshinskii-Moriya interaction is estimated to have a large energy of 1.0 mJ m-2. This work paves a path towards the skyrmionic devices based on van der Waals layered heterostructures.

217 citations


Journal ArticleDOI
05 Nov 2020-PLOS ONE
TL;DR: The ECLB-COVID19 survey revealed an increased psychosocial strain triggered by the home confinement, and a crisis-oriented interdisciplinary intervention is urgently needed to mitigate this high risk of mental disorders.
Abstract: BACKGROUND: Public health recommendations and government measures during the COVID-19 pandemic have enforced restrictions on daily-living. While these measures are imperative to abate the spreading of COVID-19, the impact of these restrictions on mental health and emotional wellbeing is undefined. Therefore, an international online survey (ECLB-COVID19) was launched on April 6, 2020 in seven languages to elucidate the impact of COVID-19 restrictions on mental health and emotional wellbeing. METHODS: The ECLB-COVID19 electronic survey was designed by a steering group of multidisciplinary scientists, following a structured review of the literature. The survey was uploaded and shared on the Google online-survey-platform and was promoted by thirty-five research organizations from Europe, North-Africa, Western-Asia and the Americas. All participants were asked for their mental wellbeing (SWEMWS) and depressive symptoms (SMFQ) with regard to "during" and "before" home confinement. RESULTS: Analysis was conducted on the first 1047 replies (54% women) from Asia (36%), Africa (40%), Europe (21%) and other (3%). The COVID-19 home confinement had a negative effect on both mental-wellbeing and on mood and feelings. Specifically, a significant decrease (p < .001 and Δ% = 9.4%) in total score of the SWEMWS questionnaire was noted. More individuals (+12.89%) reported a low mental wellbeing "during" compared to "before" home confinement. Furthermore, results from the mood and feelings questionnaire showed a significant increase by 44.9% (p < .001) in SMFQ total score with more people (+10%) showing depressive symptoms "during" compared to "before" home confinement. CONCLUSION: The ECLB-COVID19 survey revealed an increased psychosocial strain triggered by the home confinement. To mitigate this high risk of mental disorders and to foster an Active and Healthy Confinement Lifestyle (AHCL), a crisis-oriented interdisciplinary intervention is urgently needed.

194 citations


Journal ArticleDOI
TL;DR: The practical contribution of this paper is the discussion of how blockchain can alleviate the issue of financial exclusion in rural India, thereby providing a basis for a solution that could connect rural Indians to global supply chain networks.

191 citations


Journal ArticleDOI
TL;DR: It is reported that the hole transfer channel of photocharge generation is mediated by an intra-moiety excited state in a blend of donor polymer PM6 and NFA Y6 using broadband transient absorption (TA) spectroscopy, suggesting that manipulating the interplay between intra-Moiety and interfacial excited species can provide a promising route for further improving device performance.
Abstract: Bulk-heterojunction organic photovoltaic devices with nonfullerene acceptors (NFAs) exhibit efficient hole transfer with small interfacial energy offset, which results in power conversion efficiencies above 17% in single junction devices using the high-performance NFA of Y6. However, the underlying mechanism responsible for the hole transfer channel in the polymer/Y6 blends remains poorly understood. Herein, we report that the hole transfer channel of photocharge generation is mediated by an intra-moiety excited state in a blend of donor polymer PM6 and NFA Y6 using broadband transient absorption (TA) spectroscopy. By comparing the TA data recorded from the solution and film Y6 samples, we identify the ultrafast formation of an intra-moiety excimer state together with the conversion from the primary local excitation on a time scale of ∼0.2 ps in the Y6 film. The intra-moiety excimer state acts as the intermediate for the hole transfer channel, which dissociates into free polarons on a time scale of ∼15 ps in the PM6/Y6 blend at room temperature. The intra-moiety intermediate state, arising from the intermolecular coupling in Y6 domains, is markedly different from the interfacial charge transfer state, which is commonly accepted as the intermediate state for the electron transfer channel. These findings suggest that manipulating the interplay between intra-moiety and interfacial excited species can provide a promising route for further improving device performance.

174 citations


Journal ArticleDOI
10 Nov 2020-PLOS ONE
TL;DR: It is found that the triggers of mobility changes correspond well with the national announcements of mitigation measures, proving that Twitter-based mobility implies the effectiveness of those measures.
Abstract: The current COVID-19 pandemic raises concerns worldwide, leading to serious health, economic, and social challenges. The rapid spread of the virus at a global scale highlights the need for a more harmonized, less privacy-concerning, easily accessible approach to monitoring the human mobility that has proven to be associated with viral transmission. In this study, we analyzed over 580 million tweets worldwide to see how global collaborative efforts in reducing human mobility are reflected from the user-generated information at the global, country, and U.S. state scale. Considering the multifaceted nature of mobility, we propose two types of distance: the single-day distance and the cross-day distance. To quantify the responsiveness in certain geographic regions, we further propose a mobility-based responsive index (MRI) that captures the overall degree of mobility changes within a time window. The results suggest that mobility patterns obtained from Twitter data are amenable to quantitatively reflect the mobility dynamics. Globally, the proposed two distances had greatly deviated from their baselines after March 11, 2020, when WHO declared COVID-19 as a pandemic. The considerably less periodicity after the declaration suggests that the protection measures have obviously affected people's travel routines. The country scale comparisons reveal the discrepancies in responsiveness, evidenced by the contrasting mobility patterns in different epidemic phases. We find that the triggers of mobility changes correspond well with the national announcements of mitigation measures, proving that Twitter-based mobility implies the effectiveness of those measures. In the U.S., the influence of the COVID-19 pandemic on mobility is distinct. However, the impacts vary substantially among states.

172 citations


Journal ArticleDOI
TL;DR: It is found that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to pollination of most study crops in major crop-producing regions.
Abstract: Most of the world's crops depend on pollinators, so declines in both managed and wild bees raise concerns about food security. However, the degree to which insect pollination is actually limiting current crop production is poorly understood, as is the role of wild species (as opposed to managed honeybees) in pollinating crops, particularly in intensive production areas. We established a nationwide study to assess the extent of pollinator limitation in seven crops at 131 locations situated across major crop-producing areas of the USA. We found that five out of seven crops showed evidence of pollinator limitation. Wild bees and honeybees provided comparable amounts of pollination for most crops, even in agriculturally intensive regions. We estimated the nationwide annual production value of wild pollinators to the seven crops we studied at over $1.5 billion; the value of wild bee pollination of all pollinator-dependent crops would be much greater. Our findings show that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to pollination of most study crops in major crop-producing regions.

Journal ArticleDOI
TL;DR: There are major sleep problems and psychological disorders associated with the reduction of movement and activities, as well as the reduced social interaction during periods of isolation, and potential tactics to overcome these negative effects include home-based exercise, exergaming, dancing to music, and participation in yoga.
Abstract: The COVID-19 pandemic has created an unprecedented worldwide public health concern. Characterized by rapid and high frequency human-to-human transmission, the World Health Organization has recommended implementation of public health measures, including isolation of all suspected infectious individuals for a 14-day quarantine period, while governments have introduced "social distancing" and "lock-downs" of varying severity to curtail COVID-19 spread. Recent COVID-19 research further suggests there are major sleep problems and psychological disorders (e.g., stress, anxiety, depression) associated with the reduction of movement and activities, as well as the reduced social interaction. There have been no studies examining the effect of physical activity at home during such periods of isolation. However, based on previous research, potential tactics to overcome these negative effects include home-based exercise, exergaming, dancing to music, and participation in yoga. Adults should accumulate at least 150 min of moderate-intensity and at least 75 min of vigorous-intensity of activity divided in to 5-7 sessions per week. This training volume could be reduced by 30% for children and adolescents if replaced by recess or active play in and around the home. Additionally, exercises should be adapted to the fitness level of the participant and a progressive model of intensity and training volume should be utilized, preferably monitored by telephone applications and wearable sensors.

Journal ArticleDOI
TL;DR: In this paper, the authors present five research directions related to COVID-19 pandemic impacts on jobs, i.e., job loss, job changes, job outcomes, coping, and support.

Journal ArticleDOI
TL;DR: It is found that perceived discrimination was a central predictor of mental illness, and preventing and addressing social stigma associated with COVID-19 may be crucial for improving mental health for recovered patients.
Abstract: The coronavirus disease 2019 (COVID-19) pandemic can have a profound impact on the mental health of patients who survived the illness. However, little is known about the prevalence rate of mental health disorders among hospital discharged COVID-19 patients and its associated factors. A cross-sectional survey of hospital discharged patients was conducted April 11-22, 2020 in Wuhan, China (where the pandemic began). 675 participants completed the survey, including 90 (13.3%) medical staff (physicians and nurses who had been ill). We used Fisher's exact test and multivariable logistic regression methods to explore the risk factors associated with mental health problems (anxiety, depression, and PTSD symptoms associated with COVID-19 hospitalization). Adverse mental health effects of COVID-19 are evident after discharge from the hospital, with sleep difficulties highlighted as a central issue. As we found that perceived discrimination was a central predictor of mental illness, preventing and addressing social stigma associated with COVID-19 may be crucial for improving mental health for recovered patients.

Journal ArticleDOI
TL;DR: The modulation strategies for LLC resonant converter can be categorized into three groups: 1) input voltage fundamental harmonic modulation; 2) resonant tank elements modulation; and 3) secondary equivalent impedance modulation.
Abstract: In this article, based on the LLC resonant converter fundamental harmonic analysis model, the modulation strategies for LLC resonant converter can be categorized into the following three groups: 1) input voltage fundamental harmonic modulation; 2) resonant tank elements modulation; and 3) secondary equivalent impedance modulation. Operational principles and control diagrams for different modulation strategies are given. Comprehensive comparisons between these modulation strategies in terms of topology complexity, control complexity, and voltage gain range are presented with respect to the same system specifications. The advantages and disadvantages for each modulation strategy are summarized to provide guidance for engineers when analyzing and designing an LLC resonant converter. The hybrid modulation strategies are categorized into different groups based on the specific applications. Brief introductions of these hybrid modulation strategies are presented. Future trends regarding the modulation strategies of LLC resonant converters are presented.

Journal ArticleDOI
TL;DR: In this article, the Dzyaloshinskii-Moriya interactions are used to identify strong enough DMIs, which leads to not only helical cycloid phases, but also to topologically nontrivial states, such as the intrinsic domain wall skyrmions in the Janus monolayers, and the magnetic-field induced bimerons in the top-layer Br or Cl atoms.
Abstract: Topological magnetic states are promising for ultradense memory and logic devices. Recent progress in two-dimensional magnets encourages the idea to realize topological states, such as skyrmions and merons, in freestanding monolayers. However, monolayers such as ${\mathrm{CrI}}_{3}$ lack Dzyaloshinskii-Moriya interactions (DMIs) and thus do not naturally exhibit skyrmions/merons but rather a ferromagnetic state. Here we propose the fabrication of $\mathrm{Cr}{(\mathrm{I},X)}_{3}$ Janus monolayers, in which the Cr atoms are covalently bonded to the underlying I ions and top-layer Br or Cl atoms. By performing first-principles calculations and Monte Carlo simulations, we identify strong enough DMIs, which leads to not only helical cycloid phases, but also to topologically nontrivial states, such as the intrinsic domain wall skyrmions in $\mathrm{Cr}{(\mathrm{I},\mathrm{Br})}_{3}$ and the magnetic-field-induced bimerons in $\mathrm{Cr}{(\mathrm{I},\mathrm{Cl})}_{3}$. Microscopic origins of such spin textures are revealed as well.

Journal ArticleDOI
TL;DR: B berries have been demonstrated to alleviate symptoms of gut inflammation through the modulation of pro-inflammatory cytokines and have chemopreventive effects towards colon cancer through the regulation of apoptosis, cell proliferation and angiogenesis.
Abstract: Berries are rich in phenolic compounds such as phenolic acids, flavonols and anthocyanins. These molecules are often reported as being responsible for the health effects attributed to berries. However, their poor bioavailability, mostly influenced by their complex chemical structures, raises the question of their actual direct impact on health. The products of their metabolization, however, may be the most bioactive compounds due to their ability to enter the blood circulation and reach the organs. The main site of metabolization of the complex polyphenols to smaller phenolic compounds is the gut through the action of microorganisms, and reciprocally polyphenols and their metabolites can also modulate the microbial populations. In healthy subjects, these modulations generally lead to an increase in Bifidobacterium, Lactobacillus and Akkermansia, therefore suggesting a prebiotic-like effect of the berries or their compounds. Finally, berries have been demonstrated to alleviate symptoms of gut inflammation through the modulation of pro-inflammatory cytokines and have chemopreventive effects towards colon cancer through the regulation of apoptosis, cell proliferation and angiogenesis. This review recapitulates the knowledge available on the interactions between berries polyphenols, gut microbiota and gut health and identifies knowledge gaps for future research.

Journal ArticleDOI
20 Aug 2020
TL;DR: In this article, a GeSn/SiGeSn heterostructure diode was grown on a Si substrate in a ridge waveguide laser device and tested under pulsed conditions.
Abstract: Monolithic lasers on Si have long been anticipated as an enabler of full photonic integration, and significant progress in GeSn material development shows promise for such laser devices. While there are many reports focused on optically pumped lasers, in this work, we demonstrate electrically injected GeSn lasers on Si. We grew a GeSn/SiGeSn heterostructure diode on a Si substrate in a ridge waveguide laser device and tested it under pulsed conditions, giving consideration to the structure design to enhance the carrier and optical confinement. The peak linewidth of 0.13 nm (0.06 meV) and injection current curves indicated lasing, which was observed up to 100 K with emission peaks at 2300 nm. We recorded a threshold of 598A/cm2 at 10 K. The peak power and external quantum efficiency were 2.7 mW/facet and 0.3%, respectively. The results indicate advances for group-IV-based lasers, which could serve as a promising route for laser integration on Si.

Journal ArticleDOI
TL;DR: This study presents the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species and classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions.

Journal ArticleDOI
TL;DR: This preliminary work provides practitioners with a glimpse of what lies ahead, which individuals and communities may be the most vulnerable, and what types of strategic interventions might help to address a wide range of mental health consequences for Americans in the months and years ahead.

Journal ArticleDOI
05 Sep 2020
TL;DR: A dynamic scheduling policy based on Deep Reinforcement Learning (DRL) with the Deep Deterministic Policy Gradient (DDPG) method is proposed to solve the problem of dynamic caching, computation offloading, and resource allocation in cache-assisted multi-user MEC systems with stochastic task arrivals.
Abstract: Mobile Edge Computing (MEC) is one of the most promising techniques for next-generation wireless communication systems. In this paper, we study the problem of dynamic caching, computation offloading, and resource allocation in cache-assisted multi-user MEC systems with stochastic task arrivals. There are multiple computationally intensive tasks in the system, and each Mobile User (MU) needs to execute a task either locally or remotely in one or more MEC servers by offloading the task data. Popular tasks can be cached in MEC servers to avoid duplicates in offloading. The cached contents can be either obtained through user offloading, fetched from a remote cloud, or fetched from another MEC server. The objective is to minimize the long-term average of a cost function, which is defined as a weighted sum of energy consumption, delay, and cache contents' fetching costs. The weighting coefficients associated with the different metrics in the objective function can be adjusted to balance the tradeoff among them. The optimum design is performed with respect to four decision parameters: whether to cache a given task, whether to offload a given uncached task, how much transmission power should be used during offloading, and how much MEC resources to be allocated for executing a task. We propose to solve the problems by developing a dynamic scheduling policy based on Deep Reinforcement Learning (DRL) with the Deep Deterministic Policy Gradient (DDPG) method. A new decentralized DDPG algorithm is developed to obtain the optimum designs for multi-cell MEC systems by leveraging on the cooperations among neighboring MEC servers. Simulation results demonstrate that the proposed algorithm outperforms other existing strategies, such as Deep Q-Network (DQN).

Journal ArticleDOI
TL;DR: In this article, the authors examined whether trait pathogen avoidance (operationalized as perceived vulnerability to disease; PVD) was linked with responses to COVID-19 and preventative behaviors.

Journal ArticleDOI
TL;DR: This paper proposes a joint lithium-ion battery state estimation approach that takes advantage of the data-driven least-square-support-vector-machine and model-based unscented-particle-filter and achieves the joint estimation with different time scales using the proposed hybrid joint state estimation method.

Journal ArticleDOI
TL;DR: This study shows that STM is a powerful tool for detecting and manipulating the microscopic domain structures in 2D ferroelectric monolayers, which are difficult for conventional approaches such as piezoresponse force microscopy, thus facilitating the hunt for other 2DFerroelectricMonolayers with in-plane polarization with important technological applications.
Abstract: Two-dimensional (2D) van der Waals ferroelectrics provide an unprecedented architectural freedom for the creation of artificial multiferroics and nonvolatile electronic devices based on vertical an...

Journal ArticleDOI
TL;DR: This review summarises recent advances in strategies reported by international researchers and engineers concerning how to tackle COVID-19 via rapid testing, mainly through nucleic acid- and antibody testing.

Journal ArticleDOI
TL;DR: The investigation of the Kitaev physics and possible Kitaeva QSL state in epitaxially strained Cr-based monolayers, such as CrSiTe_{3}, that rather possess a S=3/2 spin value is reported, which extends the playground of Kitaov physics and QSLs to 3d transition metal compounds.
Abstract: Quantum spin liquids (QSLs) form an extremely unusual magnetic state in which the spins are highly correlated and fluctuate coherently down to the lowest temperatures, but without symmetry breaking and without the formation of any static long-range-ordered magnetism. Such intriguing phenomena are not only of great fundamental relevance in themselves, but also hold promise for quantum computing and quantum information. Among different types of QSLs, the exactly solvable Kitaev model is attracting much attention, with most proposed candidate materials, e.g., RuCl_{3} and Na_{2}IrO_{3}, having an effective S=1/2 spin value. Here, via extensive first-principles-based simulations, we report the investigation of the Kitaev physics and possible Kitaev QSL state in epitaxially strained Cr-based monolayers, such as CrSiTe_{3}, that rather possess a S=3/2 spin value. Our study thus extends the playground of Kitaev physics and QSLs to 3d transition metal compounds.

Journal ArticleDOI
TL;DR: The current study examines interrelationships between social vulnerability, individual stressors, social and psychological resources, and depressive symptomatology among US adults during the current coronavirus disease 2019 (COVID‐19) pandemic.
Abstract: Background The current study examines interrelationships between social vulnerability, individual stressors, social and psychological resources, and depressive symptomatology among US adults during the current coronavirus disease 2019 (COVID-19) pandemic. Methods Using an online survey platform, a poststratified (by age, gender, race, income, and geography), representative sample (n = 10,368 adults) is used in the analysis. Results On average, sample respondents report Center for Epidemiological Studies Depression (CES-D) Scale symptomatology nearly a point higher than the often used cutoff score for clinical caseness (16+); one-third of respondents had CES-D scores higher than 25. Multiple regression results show elevated levels of depressive symptomatology among the socially vulnerable (women, Hispanic, unmarried, not working). Those persons expressing heightened COVID-19 fear and moderate to high levels of food insecurity report more depressive symptoms than persons with less fear and low or no food insecurity. All three of the resource variables (mastery of fate, strength of ties, and optimism) are significant and in the negative direction. Conclusions In a snapshot, the data provide an important point prevalence assessment of adult depressive symptoms during the current public health crisis. Results highlight the significance of vulnerability and individual stressors in the wake of the COVID-19 pandemic. In addition, the analysis affirms the importance of access to social and psychological resources to combat heightened fear and anxiety that persons report during the current pandemic.

Journal ArticleDOI
TL;DR: The authors showed that peatland ET increases more than forest ET with increasing VPD using observations from 95 eddy covariance tower sites, indicating a stronger warming response in peatlands.
Abstract: The response of evapotranspiration (ET) to warming is of critical importance to the water and carbon cycle of the boreal biome, a mosaic of land cover types dominated by forests and peatlands. The effect of warming-induced vapour pressure deficit (VPD) increases on boreal ET remains poorly understood because peatlands are not specifically represented as plant functional types in Earth system models. Here we show that peatland ET increases more than forest ET with increasing VPD using observations from 95 eddy covariance tower sites. At high VPD of more than 2 kPa, peatland ET exceeds forest ET by up to 30%. Future (2091–2100) mid-growing season peatland ET is estimated to exceed forest ET by over 20% in about one-third of the boreal biome for RCP4.5 and about two-thirds for RCP8.5. Peatland-specific ET responses to VPD should therefore be included in Earth system models to avoid biases in water and carbon cycle projections. Climate warming increases evapotranspiration (ET) more in boreal peatlands than in forests. Observations show that peatland ET can exceed forest ET by up to 30%, indicating a stronger warming response in peatlands. Earth system models do not fully account for peatlands and hence may underestimate future boreal ET.

Journal ArticleDOI
TL;DR: In today's turbulent business environments, work teams frequently face a variety of adverse conditions and, as a result, can experience process breakdowns and performance declines as mentioned in this paper, despite existing...
Abstract: In today’s turbulent business environments, work teams frequently face a variety of adverse conditions and, as a result, can experience process breakdowns and performance declines. Despite existing...

Journal ArticleDOI
TL;DR: These results provide some insight on the impact COVID‐19 is having on the general U.S. population and practitioners should be prepared for what will likely be a significant mental health fall‐out in the months and years ahead.
Abstract: OBJECTIVE: The current paper examines the intersection between social vulnerability, individual risk, and social/psychological resources with adult suicidality during the COVID-19 pandemic METHOD: Data come from a national sample (n = 10,368) of US adults Using an online platform, information was gathered during the third week of March 2020, and post-stratification weighted to proportionally represent the US population in terms of age, gender, race/ethnicity, income, and geography RESULTS: Nearly 15 percent of sampled respondents were categorized as high risk, scoring 7+ on the Suicide Behaviors Questionnaire-Revised (SBQ-R) This level of risk varied across social vulnerability groupings: Blacks, Native Americans, Hispanics, families with children, unmarried, and younger respondents reported higher SBQ-R scores than their counterparts (p < 000) Regression results confirm these bivariate differences and also reveal that risk factors (food insecurity, physical symptoms, and CES-D symptomatology) are positive and significantly related to suicidality (p < 000) Additionally, resource measures are significant and negatively related to suicidality (p < 000) CONCLUSIONS: These results provide some insight on the impact COVID-19 is having on the general US POPULATION: Practitioners should be prepared for what will likely be a significant mental health fall-out in the months and years ahead