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This study was aimed to explore the influence of COVID-19 pandemic on elementary school students from cross-level perspective. With a cross-section survey, 823 elementary school students (Mage = 11.89, SD = 1.30) from 49 classes participated in the survey, which includes participants' demographic variables (e.g., gender) and studied variables assessing by depression, anxiety, COVID-19 related stress and other relevant variables. The hierarchical linear model was used to analyze the relationship among studied variables. Results showed that the detection rate of elementary school students' anxiety and depression symptoms were 24.2% and 23.3% respectively, which was higher than that before the pandemic broke out. For the influencing factors of elementary school student's psychological symptoms, at the individual level, both online learning satisfaction and problem-based coping strategy were negatively related with student's psychological symptoms, while both emotion-based coping strategy and pandemic-related stressors were positively related with them. Furthermore, emotion-based coping strategy could strengthen the positive relation between pandemic-related stressors and psychological symptoms. Emotion-based coping strategy (or online learning satisfaction) at the class level positively (or negatively) predicted psychological symptoms. The findings could add new knowledge about the influence of COVID-19 pandemic on elementary school students' psychological symptoms, and are useful in promoting elementary school students' mental health when the pandemic broke out. [ABSTRACT FROM AUTHOR]

We prove a generalization of a well-known theorem of Rado for continuous CR functions on a class of bihololomorphically invariant hypersurfaces that are considerably larger than convex ones of finite type and strictly pseudoconvex hypersurfaces. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the association and the underlying mechanism between parental conflict and adolescent depression during the COVID-19 pandemic. In a longitudinal study, a total of 655 Chinese adolescents ranging from 13 to 16 years old completed a three-wave survey (W1, W2, W3) via a survey website. The data was collected three times: March 15–20, 2020 (W1, the outbreak period of the COVID-19 pandemic in Mainland China), June 20–25, 2020 (W2, the trough stage), and December 15–20, 2020 (W3, six months after the trough stage). The SPSS 16.0 software was used to investigate the relationships among study variables. The findings showed that a double-hump effect was found for depression detection among adolescents during the pandemic, with depression rates in W1 (26.9%) and W3 (29%) were higher than that in W2 (21.9%). The parental conflict subscales of content and resolution had a greater impact on adolescent adjustment than other subscales. The parental conflict had direct and indirect impacts (through reducing family support and increasing burdensomeness) on adolescent depression symptoms in W3. It was concluded that when the COVID-19 pandemic was in a trough curve for more than six months, adolescent adjustment was significantly impacted by the pandemic, and parental conflict was an important risk factor in predicting individual adjustment. Therefore, family intervention is recommended when improving adolescent adjustment during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

A version of the classical Kerner's theorem for a singular Stein space Ω with a compact strongly pseudoconvex boundary has been recently established by Huang–Xiao (J Reine Angew Math 770:183–203, 2021) when dim C Ω ≥ 3 . A partial result for the case of complex dimension two was also obtained in Huang and Xiao (J Reine Angew Math 770:183–203, 2021). In this paper, we answer the two dimensional case left open in Huang and Xiao (J Reine Angew Math 770:183–203, 2021) in its full generality. [ABSTRACT FROM AUTHOR]

Oral microbiota is vital for human health and can be affected by various factors (i.e. diets, ethnicity). However, few studies have compared oral microbiota of individuals from different nationalities in the same environment. Here, we explored the assembly and interaction of oral microbial communities of Chinese and Pakistanis in one university. Firmicutes and Proteobacteria were the predominant microorganisms in the oral cavity of Chinese and Pakistanis. Streptococcus and Neisseria were the dominant genera of China, while Streptococcus and Haemophilus were the dominant genera of Pakistanis. In addition, the oral community membership and structure were not influenced by season, Chinese/Pakistani student and gender, reflecting the stability of the human oral microbiome. The beta diversity of oral microbiomes between Chinese and Pakistanis significantly differed in winter, but not in spring. The alpha diversity of Chinese students and Pakistani students was similar. Moreover, oral microbial community of both Chinese and Pakistani students was mainly driven by stochastic processes. The microbial network of Chinese was more complexity and stability than that of Pakistanis. Our study uncovers the characteristics of human oral microbiota, which is of great significance for oral and human health. [ABSTRACT FROM AUTHOR]

Spatial ability is an influential factor for academic performance in Science, Technology, Engineering, and Mathematics (STEM) education. However, the roles of spatial strategies are unclear. Therefore, coupling with virtual Starmaze developed by fields of cognitive neuroscience, this study aimed to explore spatial strategy among STEM students and its role in academic performance. A virtual Starmaze was constructed to test how students complete a navigation test. A total of 172 college students majoring in STEM participated in this study. Modeling analysis showed students tend to use allocentric strategy when the difficulty of spatial tasks increased. Results further showed students with high STEM academic performance tended to use allocentric strategy while ones with low STEM academic performance tended to use egocentric strategy. Specifically, academic performances in science and mathematics learning were associated with the allocentric strategy, while academic performances in technology and engineering learning were associated with proficiency and hands-on ability. [ABSTRACT FROM AUTHOR]

We give simple and unified proofs of weak holomorhpic Morse inequalities on complete manifolds, q-convex manifolds, pseudoconvex domains, weakly 1-complete manifolds and covering manifolds. This paper is essentially based on the asymptotics of Bergman kernel functions and the Bochner–Kodaira–Nakano formulas. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) process has attracted much attention in recent years for the direct conversion of CH4 and CO2 into high-value-added syngas. The key for DRM was to develop catalysts with high activity and stability. In this study, LaNiO3 was prepared by the sol-gel, co-precipitation, and hydro-thermal methods to explore the influence of preparation methods on the catalyst structure and DRM reaction performance. The regeneration properties of the used LaNiO3 catalysts were also investigated under steam, CO2, and air atmospheres, respectively. The results showed that LaNiO3 prepared by sol-gel method showed the best DRM performance at 750°C. The DRM performance of the samples prepared by hydro-thermal method was inhibited at 750°C due to the residual of Na+ ions during the preparation process. The regeneration tests showed that none of the three atmospheres could restore LaNiO3 perovskite phase in the samples, but they could eliminate the carbon deposits in the samples during the DRM reaction, so the samples could maintain stable DRM performance at different cycling stages. [ABSTRACT FROM AUTHOR]

The deep mechanisms shaping bacterial assembly are a crucial challenge in drinking water ecosystem. However, much less is known about seasonal diversity distributions and assembly mechanisms of abundant and rare bacteria in drinking water. The combination of environmental variables and high-throughput 16S rRNA gene sequencing was conducted to examine the composition, assembly, co-occurrence patterns of abundant and rare bacteria from five drinking water sites across four seasons in one year in China. The results indicated that abundant taxa were mainly composed of Rhizobiales_UG1, Sphingomonadales_UG1, and Comamonadaceae, while rare taxa were Sphingomonadales_UG1, Rhizobiales_UG2, and Rhizobiales_UG1. The richness of rare bacteria was greater than that of abundant ones, and the richness had no differences among seasons. The beta diversity was significantly discrepant in abundant and rare communities and among seasons. Deterministic mechanism accounted for a larger contribution to abundant taxa than rare taxa. Furthermore, water temperature had higher effects on abundant microbiome than rare ones. Co-occurrence network analysis indicated that abundant taxa that occupied frequently in central positions had stronger effect on co-occurrence network. In our study, these results collectively suggested that rare bacteria respond to environmental variables with an analogical pattern to abundant counterparts (similar community assembly), but their ecological diversities, driving forces, and co-occurrence patterns were not equivalent in drinking water. [ABSTRACT FROM AUTHOR]

Meaningful learning for conceptual change in science education should aim to help students change their existing misconceptions to develop an accurate understanding of scientific concepts. Although collaborative argumentation is assumed to support such processes, its value for conceptual change is unclear. Moreover, the roles of argumentative dialogue should be considered in studies on collaborative argumentation. In the present study, using a controlled experiment, we examined the value of collaborative argumentation for conceptual change in science education while fully considering the roles of argumentative dialogue. Twenty-three postgraduate students were each allocated to one of two conditions (individual argumentation [control group] and collaborative argumentation [experimental group]) and participated in two argumentation activities. The results revealed that collaborative argumentation had a delayed but long-lasting effect on conceptual change in science education (i.e., conceptual change induced by collaborative argumentation did not immediately indicate a significant improvement at the moments of argumentation but showed a significant improvement during the delay period). Collaborative argumentation provided opportunities for change in cognitive, ontological, intentional, and other aspects of learning. Dialogue protocol analysis revealed that long-lasting conceptual change was associated with a U-shaped pattern of argumentative dialogue (i.e., two high and one low: both deliberative argumentation and co-consensual construction frequently occurred, while disputative argumentation rarely occurred) in collaborative argumentation. A third argumentation activity was then conducted to confirm this unexpected finding. The results confirmed an association between long-lasting conceptual change and a U-shaped pattern of argumentative dialogue in collaborative argumentation. The current study sheds light on the value of collaborative argumentation for long-lasting conceptual change, deepening our understanding of whether conceptual gains from argumentation activities were contingent on a particular type of verbal dialogue powered by collaborative argumentation. Implications for science education were discussed. [ABSTRACT FROM AUTHOR]

Spatial ability is a powerful systematic source of individual differences in the areas of science, technology, engineering, and technology (STEM). Abundant research has evidenced that psychometrically assessed spatial ability is a strong predictor of STEM achievement. However, its underlying cognitive process and relevant role in STEM education are unknown. From the perspective of cognitive neuroscience, spatial ability is also considered a human intelligence deriving from the cognitive processing of spatial information in the brain. With the help of the cognitive neuroscience paradigm of spatial navigation, in the present work, we investigate the spatial cognitive process among STEM students and its role in STEM education. A total of 172 undergraduates majoring in veterinary science participated in a spatial navigation test. Participants attempted to return a toy to its original place in an arena when given either internal self-motion cues only, external landmark cues only, or both in a spatial navigation task. Modelling analysis of 172 participants' spatial navigation behaviours showed that all the participants' spatial cognitive processes featured navigation cue integration. The results of the different tests showed that students with higher levels of navigation cue integration had better academic performance in STEM learning. The results also indicated that, surprisingly, better academic performance in science and mathematics relied more on the use of internal self-motion cues, while better academic performance in engineering and technology relied more on the use of external landmark cues. This study sheds some light on the spatial cognitive process and its role in STEM education from the cognitive neuroscience perspective, thus deepening the functional understanding of spatial ability as a systemic source of individual differences for STEM education, and provides an empirical reference point for interdisciplinary studies on the role of cognition in the context of STEM education. Implications on STEM learning design and STEM teaching were discussed. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of infertility on Chinese women's life satisfaction. Infertile women (n = 466) who were seeking medical help completed a survey that included the Fertility Problem Inventory (FPI), the Dyadic Adjustment Questionnaire (DAS), the Connor-Davidson Resilience Scale (CD-RISC), the Satisfaction with Life Scale, and demographic variables. We used a moderated mediation model to test our hypotheses, with life satisfaction as the dependent variable, representations about the importance of parenthood as the independent variable, the impact of infertility on life domains as a mediator, and marital satisfaction and resilience as moderators. Results showed that representations about the importance of parenthood and the impact of infertility on life domains are two main types of infertility-related stress, which could play independent roles in predicting life satisfaction. Representations about the importance of parenthood had a negative indirect effect on life satisfaction through the impact of infertility on life domains, and the indirect effect of the impact of infertility on life domains was moderated by marital satisfaction and resilience. Specially, representations about the importance of parenthood had a weaker indirect effect (through the impact of infertility on life domains) on life satisfaction in individuals with higher marital satisfaction or resilience. Therefore, the type of infertility-related stress and both marital satisfaction and resilience should be addressed in psychological interventions for women coping with infertility in mainland China. [ABSTRACT FROM AUTHOR]

Here reports a hollow cube NiCo2S4 nanomaterial, which was prepared via facile hydroxylation and sulfuration steps using the self-prepared ZIF-67 as a precursor. This kind of NiCo2S4 as an electrode material for supercapacitor presents a specific capacitance high up to 1350 F g-1 at 1 A g-1 due to the contribution of pseudocapacitance. Particularly, the hybrid supercapacitor PC//NiCo2S4, assembled using the NiCo2S4 as the positive electrode material and the PC as the negative electrode material, delivers a high energy density of 33 Wh kg-1 at the power density of 800 W kg-1. Meanwhile, it presents a good cyclic stability with 67% capacitance retention after 10,000 cycles of charge–discharge at the current density of 5 A g-1. However, the rate capability is not good enough because of the polarization effect of NiCo2S4 as a battery-type electrode material. Therefore, this research provides a reference for enhancing capacitance performance of an electrode material. For instance, reversibility in redox reaction and stability in structure are more important than the capacity in many cases. Preparation of a hollow cube NiCo2S4 and its application in supercapacitor. [ABSTRACT FROM AUTHOR]

We study the stable embedding problem for a CR family of 3-dimensional strongly pseudoconvex CR manifolds with each fiber bounding a stein manifold. [ABSTRACT FROM AUTHOR]

In this project, we (1) explore perceptions of the social and ethical implications (SEI) of nanotechnology among US scientists who work at the nanoscale, and (2) develop and pilot test an online training module to foster consideration of social and ethical implications in the lab. To meet our first goal, we drew qualitative insights from open-ended survey data collected from scientists affiliated with the National Nanotechnology Infrastructure Network. Our data suggest that while the survey participants responded positively to the idea that consideration of SEI should be a part of the work they do, there was confusion about whether SEI refers to lab safety, research integrity, or something more. This is something we sought to address in the online training module that we developed based on that qualitative data and on feedback collected from experts in nanoethics and lab management. We then pilot tested the module with undergraduate students studying nanotechnology in the National Science Foundation's Research Experiences for Undergraduates (REU) program and with scientists registered to use a National Nanotechnology Coordinated Infrastructure-funded microelectronics research lab. The undergraduate data suggested that students appreciated the SEI training but wished professors and scientists would begin integrating the ideas therein into coursework and mentoring. The scientist data suggested that the module increased understanding of "social and ethical implications," increased the perceived need to implement SEI into workplace routines, and, interestingly, heightened perceptions of risk associated with the scientists' own work. The practical and theoretical implications of this work are discussed. [ABSTRACT FROM AUTHOR]

Neuroimaging data often take the form of high-dimensional arrays, also known as tensors. Addressing scientific questions arising from such data demands new regression models that take multidimensional arrays as covariates. Simply turning an image array into a vector would both cause extremely high dimensionality and destroy the inherent spatial structure of the array. In a recent work, Zhou et al. (J Am Stat Assoc, 108(502):540-552, 2013) proposed a family of generalized linear tensor regression models based upon the CP (CANDECOMP/PARAFAC) decomposition of regression coefficient array. Low-rank approximation brings the ultrahigh dimensionality to a manageable level and leads to efficient estimation. In this article, we propose a tensor regression model based on the more flexible Tucker decomposition. Compared to the CP model, Tucker regression model allows different number of factors along each mode. Such flexibility leads to several advantages that are particularly suited to neuroimaging analysis, including further reduction of the number of free parameters, accommodation of images with skewed dimensions, explicit modeling of interactions, and a principled way of image downsizing. We also compare the Tucker model with CP numerically on both simulated data and real magnetic resonance imaging data, and demonstrate its effectiveness in finite sample performance. [ABSTRACT FROM AUTHOR]

We prove the stability of the equivariant embedding of compact strictly pseudoconvex CR manifolds with transversal CR circle action under circle invariant deformations of the CR structures. [ABSTRACT FROM AUTHOR]

Let X be a compact strongly pseudoconvex CR manifold with a transversal CR $$S^1$$ -action. In this paper, we establish the asymptotic expansion of Szegő kernels of positive Fourier components, and by using the asymptotics, we show that X can be equivariant CR embedded into some $$\mathbb {C}^N$$ equipped with a simple $$S^1$$ -action. An equivariant embedding of quasi-regular Sasakian manifold is also derived. [ABSTRACT FROM AUTHOR]

Let X be a compact connected CR manifold of dimension $$2n-1, n\ge 2$$ with a transversal CR $$S^1$$ -action on X. We study the Fourier components of the Kohn-Rossi cohomology with respect to the $$S^1$$ -action. By studying the Szegö kernel of the Fourier components we establish the Morse inequalities on X. Using the Morse inequalities we have established on X we prove that there are abundant CR functions on X when X is weakly pseudoconvex and strongly pseudoconvex at a point. [ABSTRACT FROM AUTHOR]

In model driven architecture (MDA), system requirements are first captured by UML (unified modeling language) use cases with sequence diagrams to describe their intended use and implemented by classes of objected-oriented languages in the subsequent design stages. It is important that the dynamic behavior specified by the sequence diagrams is in full compliance with the implementation classes. This paper proposes an automatic approach and tool support for generating class contracts, which define a precondition and a postcondition for each operation of the class. The former serves as a guard to ensure invocations of the operations respect the semantics introduced by the sequence diagrams, and the latter places the system in a legal state to facilitate the succeeding operation calls. The contracts can be easily mapped to code of an object-oriented language such as Java. Thus, the approach helps to bridge the gap between the requirements and design stages of system development process. We use our model transformation tool to first generate a UML protocol state machine from the sequence diagrams, and then derive the contracts for a controller class. The transformations take into account the concurrency and critical constructs of the respective UML diagrams. [ABSTRACT FROM AUTHOR]

Model-driven architecture (MDA) has become a main stream technology for software-intensive system design. The main engineering principle behind it is that the inherent complexity of software development can only be mastered by building, analyzing and manipulating system models. MDA also deals with system complexity by providing component-based design techniques, allowing independent component design, implementation and deployment, and then system integration and reconfiguration based on component interfaces. The model of a system in any stage is an integration of models of different viewpoints. Therefore, for a model-driven method to be applied effectively, it must provide a body of techniques and an integrated suite of tools for model construction, validation, and transformation. This requires a number of modeling notations for the specification of different concerns and viewpoints of the system. These notations should have formally defined syntaxes and a unified theory of semantics. The underlying theory of the method is needed to underpin the development of tools and correct use of tools in software development, as well as to formally verify and reason about properties of systems in mission-critical applications. The modeling notations, techniques, and tools must be designed so that they can be used seamlessly in supporting development activities and documentation of artifacts in software design processes. This article presents such a method, called the rCOS, focusing on the models of a system at different stages in a software development process, their semantic integration, and how they are constructed, analyzed, transformed, validated, and verified. [ABSTRACT FROM AUTHOR]

Prototyping is an efficient and effective way to understand and validate system requirements at the early stage of software development. In this paper, we present an approach for transforming UML system requirement models with OCL specifications into executable prototypes with the function of checking multiplicity and invariant constraints. Generally, a use case in UML can be described as a sequence of system operations. A system operation can be formally defined by a pair of preconditions and postconditions specified using OCL in the context of the conceptual class model. By analyzing the semantics of the preconditions and postconditions, the execution of the operation can be prototyped as a sequence of primitive actions which first check the precondition, and then enforce the postcondition by transferring the system from a pre-state to a post-state step by step. The primitive actions are basic manipulations of the system state (an object diagram), including find objects and links, create and remove objects and links, and check and set attribute values. Based on this approach, we have developed a tool of automatic prototype generation and analysis: AutoPA3.0. [ABSTRACT FROM AUTHOR]

Mean Value Calculus (MVC)[1] is a real-time logic which can be used to specify and verify real-time systems[2]. As a conservative extension of Duration Calculus (DC)[3], MVC increases the expressive power but keeps the properties of DC. In this paper we present decidability results of MVC. An interesting result is that propositional MVC with chop star operator is still decidable, which develops the results of [4] and [5]. [ABSTRACT FROM AUTHOR]

We aimed to investigate the molecular epidemic characteristics and viral transmission patterns of HIV-1 in a typical labor export area, Guangyuan city, China. Based on conducting phylogenetic trees and molecular transmission networks, a phylogenetic analysis was performed on HIV-1 pol sequences obtained from 211 migrant-history workers, 83 non-migrant-history individuals, and 21 migrant-history unknown individuals between January, 2012 and February, 2017 in Guangyuan city. Phylogenetic analysis revealed that CRF07_BC (48.3%, n = 152) and CRF01_AE (33.3%, n = 105) were the dominant strains in Guangyuan city, and circulated by multiple lineages with various epidemic characteristics. Geographic network analysis showed that Guangyuan city-related sequences with 20.3% CRF07_BC and 28.3% CRF01_AE were linked to that of other provinces, compared to that with 1.7% CRF07_BC and 5.0% CRF01_AE in cities of Sichuan. Molecular transmission network analysis further illustrated that migrant-history workers linked more sequences from other provinces than non-migrant-history individuals in both CRF07_BC (29.3% versus 0.0%, P = 0.013) and CRF01_AE (40.5% versus 10.0%, P = 0.001) networks. Our results highlighted that migrant-history workers in recent year played a vital role in fueling HIV-1 epidemic in Guangyuan city. Molecular transmission network analysis could be a useful approach for disclosing the transmission mechanism of HIV, which should be used in prevention and intervention efforts. [ABSTRACT FROM AUTHOR]

Although several Si/C composite structures have been proposed for high-performance lithium-ion batteries (LIBs), they have still suffered from expensive and complex processes of nano-Si production. Herein, a simple, controllable oxygen inward diffusion was utilized to transform Si sludge obtained from the photovoltaic (PV) industry into the nano-Si/SiOx structure as a result of the high diffusion efficiency of O inside Si and high surface area of the sludge. After further process, a yolk/shell Si/C structure was obtained as an anode material for LIBs. This composite demonstrated an excellent cycling stability, with a high reversible capacity (∼ 1250 mAh/g for 500 cycles), by void space originally left by the SiOx accommodate inner Si expansion. We believe this is a rather simple way to convert the waste Si into a valuable nano-Si for LIB applications. [ABSTRACT FROM AUTHOR]