Structural equation modeling (SEM) is a versatile multivariate statistical technique, and applications have been increasing since its introduction in the 1980s. This paper provides a critical review ...of 84 articles involving the use of SEM to address construction related problems over the period 1998–2012 including, but not limited to, seven top construction research journals. After conducting a yearly publication trend analysis, it is found that SEM applications have been accelerating over time. However, there are inconsistencies in the various recorded applications and several recurring problems exist. The important issues that need to be considered are examined in research design, model development and model evaluation and are discussed in detail with reference to current applications. A particularly important issue concerns the construct validity. Relevant topics for efficient research design also include longitudinal or cross-sectional studies, mediation and moderation effects, sample size issues and software selection. A guideline framework is provided to help future researchers in construction SEM applications.
•The basic concepts of SEM and its applications in construction research are introduced.•Critical issues from research design to model evaluation are discussed.•SEM applications in the construction are analyzed quantitatively.•Guidelines are provided for handling SEM correctly.
The role of new energy in carbon neutral ZOU, Caineng; XIONG, Bo; XUE, Huaqing ...
Petroleum exploration and development,
April 2021, 2021-04-00, 2021-04-01, Letnik:
48, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Carbon dioxide is an important medium of the global carbon cycle, and has the dual properties of realizing the conversion of organic matter in the ecosystem and causing the greenhouse effect. The ...fixed or available carbon dioxide in the atmosphere is defined as “gray carbon”, while the carbon dioxide that cannot be fixed or used and remains in the atmosphere is called “black carbon”. Carbon neutral is the consensus of human development, but its implementation still faces many challenges in politics, resources, technology, market, and energy structure, etc. It is proposed that carbon replacement, carbon emission reduction, carbon sequestration, and carbon cycle are the four main approaches to achieve carbon neutral, among which carbon replacement is the backbone. New energy has become the leading role of the third energy conversion and will dominate carbon neutral in the future. Nowadays, solar energy, wind energy, hydropower, nuclear energy and hydrogen energy are the main forces of new energy, helping the power sector to achieve low carbon emissions. “Green hydrogen” is the reserve force of new energy, helping further reduce carbon emissions in industrial and transportation fields. Artificial carbon conversion technology is a bridge connecting new energy and fossil energy, effectively reducing the carbon emissions of fossil energy. It is predicted that the peak value of China's carbon dioxide emissions will reach 110×108 t in 2030. The study predicts that China's carbon emissions will drop to 22×108 t, 33×108 t and 44×108 t, respectively, in 2060 according to three scenarios of high, medium, and low levels. To realize carbon neutral in China, seven implementation suggestions have been put forward to build a new “three small and one large” energy structure in China and promote the realization of China's energy independence strategy.
We propose an end-to-end learning framework for segmenting generic objects in videos. Our method learns to combine appearance and motion information to produce pixel level segmentation masks for all ...prominent objects in videos. We formulate this task as a structured prediction problem and design a two-stream fully convolutional neural network which fuses together motion and appearance in a unified framework. Since large-scale video datasets with pixel level segmentations are problematic, we show how to bootstrap weakly annotated videos together with existing image recognition datasets for training. Through experiments on three challenging video segmentation benchmarks, our method substantially improves the state-of-the-art for segmenting generic (unseen) objects. Code and pre-trained models are available on the project website.
We herein report a new coordination network that deforms in a smooth and reversible manner under either thermal or pressure stimulation. Concomitantly, the organic fluorophores coordinatively bound ...to the channel in a face‐to‐face arrangement respond to this structural deformation by finely adapting their conformation and arrangement. As a result, the material exhibits a remarkable dual‐stimuli‐responsive luminescence shift across almost the entire visible region: The emission color of the crystal gradually changes from cyan to green upon heating and then to red upon pressure compression. Furthermore, each stage exhibits a linear dependence of both the emission maximum and intensity on the stimulus and is fully reversible.
Coping with pressure and heat: In response to changes in temperature and pressure, the flexible scaffold of a luminescent coordination network underwent smooth and reversible structural deformation that regulated the conformation and arrangement of the emissive organic molecules coordinatively bound to the channel in the structure. As a result, a reversible fluorescence shift across almost the entire visible region was observed (see picture).
Advanced maternal age is highly associated with a decline in oocyte quality, but effective approaches to improve it have still not been fully determined. Here, we report that in vivo supplementation ...of nicotinamide mononucleotide (NMN) efficaciously improves the quality of oocytes from naturally aged mice by recovering nicotinamide adenine dinucleotide (NAD+) levels. NMN supplementation not only increases ovulation of aged oocytes but also enhances their meiotic competency and fertilization ability by maintaining the normal spindle/chromosome structure and the dynamics of the cortical granule component ovastacin. Moreover, single-cell transcriptome analysis shows that the beneficial effect of NMN on aged oocytes is mediated by restoration of mitochondrial function, eliminating the accumulated ROS to suppress apoptosis. Collectively, our data reveal that NMN supplementation is a feasible approach to protect oocytes from advanced maternal age-related deterioration, contributing to the improvement of reproductive outcome of aged women and assisted reproductive technology.
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•NMN supplementation restores NAD+ levels in maternally aged oocytes•NMN increases the number of ovulated oocytes in aged mice•NMN enhances meiotic competency and fertilization ability of aged oocytes•NMN recovers mitochondrial function to suppress ROS-induced apoptosis in aged oocytes
Miao et al. find that in vivo supplementation of the NAD+ precursor nicotinamide mononucleotide (NMN) effectively improves the quality of maternally aged oocytes by restoring their mitochondrial function and enhancing meiotic competency, fertilization ability, and subsequent embryonic development potential. This study provides a potential strategy to improve the reproductive outcome of women of advanced maternal age.
Background and Purpose
New remedies are required for the treatment of diabetic neuropathic pain (DNP) due to insufficient efficacy of available therapies. Here, we used chemogenetic approaches ...combined with in vivo pharmacology to elucidate the role of basolateral amygdala (BLA) astrocytes in DNP pathogenesis and provide new insights into therapeutic strategies for DNP.
Experimental Approach
A streptozotocin‐induced DNP model was established. Designer receptors exclusively activated by designer drugs (DREADDs) were used to regulate astrocyte activity. Mechanical hyperalgesia was assessed using the electronic von Frey test. Anxiety‐like behaviours were detected using open field and elevated plus maze tests. Astrocytic activity was detected by immunofluorescence, and cytokine content was determined by ELISA.
Key Results
BLA astrocytes were regulated by DREADDs, and inhibition of BLA astrocytes attenuated mechanical allodynia and pain‐related negative emotions in DNP rats. In contrast, temporary activation of BLA astrocytes induced allodynia without anxious behaviours in naive rats. In addition, koumine (KM) alleviated mechanical allodynia and anxiety‐like behaviours in DNP rats, inhibited the activation of BLA astrocytes and suppressed the inflammatory response. Furthermore, persistent activation of BLA astrocytes through chemogenetics mimicked chronic pain, and KM alleviated the pain hypersensitivity and anxiety‐like behaviours.
Conclusion and Implications
DREADDs bidirectionally regulate the activity of BLA astrocytes, which proves for the first time the role of BLA astrocyte activation in the pathogenesis of DNP and represents a novel therapeutic strategy for DNP. KM ameliorates DNP, perhaps by inhibiting the activation of BLA astrocytes and reveal KM as a potential candidate for treating DNP.
Impulse noise detection is a critical issue when removing impulse noise and impulse/Gaussian mixed noise. In this paper, we propose a new detection mechanism for universal noise and a universal ...noise-filtering framework based on the nonlocal means (NL-means). The operation is carried out in two stages, i.e., detection followed by filtering. For detection, first, we propose the robust outlyingness ratio (ROR) for measuring how impulselike each pixel is, and then all the pixels are divided into four clusters according to the ROR values. Second, different decision rules are used to detect the impulse noise based on the absolute deviation to the median in each cluster. In order to make the detection results more accurate and more robust, the from-coarse-to-fine strategy and the iterative framework are used. In addition, the detection procedure consists of two stages, i.e., the coarse and fine detection stages. For filtering, the NL-means are extended to the impulse noise by introducing a reference image. Then, a universal denoising framework is proposed by combining the new detection mechanism with the NL-means (ROR-NLM). Finally, extensive simulation results show that the proposed noise detector is superior to most existing detectors, and the ROR-NLM produces excellent results and outperforms most existing filters for different noise models. Unlike most of the other impulse noise filters, the proposed ROR-NLM also achieves high peak signal-to-noise ratio and great image quality by efficiently removing impulse/Gaussian mixed noise.
Abstract
Aqueous zinc metal batteries are a viable candidate for cost-effective energy storage. However, the cycle life of the cell is adversely affected by the morphological evolution of the metal ...electrode surface upon prolonged cycling. Here, we investigate different electrochemical protocols to favour the formation of stable zinc metal electrode surface morphologies. By coupling electrochemical and optical microscopy measurements, we demonstrate that an initial zinc deposition on the metal electrode allows homogeneous stripping and plating processes during prolonged cycling in symmetric Zn||Zn cell. Interestingly, when an initially plated zinc metal electrode is tested in combination with a manganese dioxide-based positive electrode and a two molar zinc sulfate aqueous electrolyte solution in coin cell configuration, a specific discharge capacity of about 90 mAh g
−1
can be delivered after 2000 cycles at around 5.6 mA cm
−2
and 25 °C.
This paper aims to predict the future situation of global energy development. In view of this, we reviewed the history of energy use and understood that new energy sources will usher in a new era ...following oil & gas, coal and wood one after another in the past time. Although the fossil energy sources are still plenty in the world, great breakthroughs made in some key technologies and the increasing demand for ecological environmental protection both impel the third time of transformation from oil & gas to new energy sources. Sooner or later, oil, gas, coal and new energy sources will each account for a quarter of global energy consumption in the new era, specifically speaking, accounting for 32.6%, 23.7%, 30.0% and 13.7% respectively. As one of the largest coal consumer, China will inevitably face up to the situation of tripartite confrontation of the coal, oil & gas and new energy. The following forecasting results were achieved. First, the oil will be in a stable period and its annual production peak will be around 2040, reaching up to 45 × 108 t. Second, the natural gas will enter the heyday period and its annual production peak will be around 2060, reaching up to 4.5 × 1012 m3, which will play a pivotal role in the future energy sustainable development. Third, the coal has entered a high-to-low-carbon transition period, and its direct use and the discharged pollutants will be significantly reduced. In 2050, the coal will be dropped to 25% of the primary energy mix. Last, the development and utilization of new energy sources has been getting into the golden age and its proportion in the primary energy mix will be substantially enhanced. On this basis, we presented some proposals for the future energy development in China. At first, we should understand well that China's energy production and consumption has its own characteristics. Under the present situation, we should strengthen the clean and efficient use of coal resources, which is the key to solving our energy and environmental issues. Then, under the low oil price circumstance, we should keep 200 million tons of annual oil production as “the bottom line” so as to ensure national energy security and to accelerate tight gas, shale gas and other unconventional resources development. In 2030, the annual natural gas production will reach up to more than 300 Bcm. Finally, the development and utilization of new energy resources should be further strengthened and non-fossil energy sources will be expected to reach as high as 20% of the primary energy consumption by 2030.
A uniform monolayer of alkanethiol‐protected gold nanoparticle arrays with ultrahigh density have been used as microcontact‐printable charge‐trapping layers for the application in flexible flash ...memories. The new devices are compared to two reference devices with a floating gate created by thermal evaporation and electrostatic self‐assembly, and show a large memory window, long retention times and good endurance properties.
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