43 research outputs found

    Result of a year-long animal survey in a state-owned forest farm in Beijing, China

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    BackgroundArtificial forest can have great potential in serving as habitat to wildlife, depending on different management methods. As the state-owned forest farms now play a new role in ecological conservation in China, the biological richness of this kind of land-use type is understudied. Once owned by a mining company, a largest state-owned forest farm, Jingxi Forest Farm, has been reformed to be a state-owned forest farm with the purpose of conservation since 2017. Although this 116.4 km2 forest farm holds a near-healthy montaine ecosystem very representative in North China, a large proportion of artificial coniferous forest in the forest farm has been proven to hold less biodiversity than natural vegetation. This situation, however, provides a great opportunity for ecological restoration and biodiversity conservation. Therefore, from November 2019 to December 2020, we conducted a set of biodiversity surveys, whose results will serve as a baseline for further restoration and conservation.New informationHere, we report the result of a multi-taxa fauna diversity survey conducted in Jingxi Forest Farm mainly in year 2020 with explicit spatial information. It is the first survey of its kind conducted in this area, revealing a total of 19 species of mammals, 86 birds, four reptiles, two amphibians and one fish species, as well as 101 species of insects. Four species of mammals are identified as data-poor species as they have less than 100 occurrence records with coordination in the GBIF database. One species of insect, representing one new provincial record genus of Beijing, is reported

    Lipid droplet remodeling and interaction with mitochondria in mouse brown adipose tissue during cold treatment

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    Brown adipose tissue (BAT) maintains animal body temperature by non-shivering thermogenesis, which is through uncoupling protein 1 (UCP1) that uncouples oxidative phosphorylation and utilizes β-oxidation of fatty acids released from triacylglycerol (TAG) in lipid droplets (LDs). Increasing BAT activity and “browning” other tissues such as white adipose tissue (WAT) can enhance the expenditure of excess stored energy, and in turn reduce prevalence of metabolic diseases. Although many studies have characterized the biology of BAT and brown adipocytes, BAT LDs especially their activation induced by cold exposure remain to be explored. We have isolated LDs from mouse interscapular BAT and characterized the full proteome using mass spectrometry. Both morphological and biochemical experiments showed that the LDs could tightly associate with mitochondria. Under cold treatment mouse BAT started expressing LD structure protein PLIN-2/ADRP and increased expression of PLIN1. Both hormone sensitive lipase (HSL) and adipose TAG lipase (ATGL) were increased in LDs. In addition, isolated BAT LDs showed increased levels of the mitochondrial protein UCP1, and prolonged cold exposure could stimulate BAT mitochondrial cristae biogenesis. These changes were in agreement with the data from transcriptional analysis. Our results provide the BAT LD proteome for the first time and show that BAT LDs facilitate heat production by coupling increasing TAG hydrolysis through recruitment of ATGL and HSL to the organelle and expression of another LD resident protein PLIN2/ADRP, as well as by tightly associating with activated mitochondria. These findings will benefit the study of BAT activation and the interaction between LDs and mitochondria

    A Hybrid Shuffled Frog Leaping Algorithm and Its Performance Assessment in Multi-Dimensional Symmetric Function

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    Ensemble learning of swarm intelligence evolutionary algorithm of artificial neural network (ANN) is one of the core research directions in the field of artificial intelligence (AI). As a representative member of swarm intelligence evolutionary algorithm, shuffled frog leaping algorithm (SFLA) has the advantages of simple structure, easy implementation, short operation time, and strong global optimization ability. However, SFLA is susceptible to fall into local optimas in the face of complex and multi-dimensional symmetric function optimization, which leads to the decline of convergence accuracy. This paper proposes an improved shuffled frog leaping algorithm of threshold oscillation based on simulated annealing (SA-TO-SFLA). In this algorithm, the threshold oscillation strategy and simulated annealing strategy are introduced into the SFLA, which makes the local search behavior more diversified and the ability to escape from the local optimas stronger. By using multi-dimensional symmetric function such as drop-wave function, Schaffer function N.2, Rastrigin function, and Griewank function, two groups (i: SFLA, SA-SFLA, TO-SFLA, and SA-TO-SFLA; ii: SFLA, ISFLA, MSFLA, DSFLA, and SA-TO-SFLA) of comparative experiments are designed to analyze the convergence accuracy and convergence time. The results show that the threshold oscillation strategy has strong robustness. Moreover, compared with SFLA, the convergence accuracy of SA-TO-SFLA algorithm is significantly improved, and the median of convergence time is greatly reduced as a whole. The convergence accuracy of SFLA algorithm on these four test functions are 90%, 100%, 78%, and 92.5%, respectively, and the median of convergence time is 63.67 s, 59.71 s, 12.93 s, and 8.74 s, respectively; The convergence accuracy of SA-TO-SFLA algorithm on these four test functions is 99%, 100%, 100%, and 97.5%, respectively, and the median of convergence time is 48.64 s, 32.07 s, 24.06 s, and 3.04 s, respectively

    Green product design with competition and fairness concerns in the circular economy era

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    In this paper, we consider green product design in a supply chain consisting of one manufacturer and two retailers, where retailer 1 aims at monetary profit maximisation, and retailer 2 has fairness concern. We consider two kinds of green products: a marginal-intensive green product (MIGP) and a development-intensive green product (DIGP). For the former, the green investment cost depends on the green level and the production quantity; while for the latter, the green investment cost depends on the green level solely. In each case, we investigate the impact of the retailer’s fairness concern by comparing the optimal solutions and supply chain performance with those in the basic models in which all the supply chain members aim at profit maximisation. We find that retailer 2 will set a higher retailing price and earn a smaller market share. Such inferiority increases as retailer 2’s inequity aversion increases or as the substitutability degree of the products offered by the two retailers increases. We also find that retailer 2’s fairness concern will always harm the manufacturer. If an equity outcome is achieved, the supply chain may achieve a better performance; however, if an inequity outcome is attained, the supply chain always performs worse

    Do High Performers Always Obtain Supervisory Career Mentoring? The Role of Perspective-Taking

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    Drawing on social exchange theory, this study examines when and why high performers may fail to obtain supervisory career mentoring (SCM). Although high performance by protégés often makes SCM more efficient and successful, we argue that supervising mentors may be reluctant to offer SCM due to the victimization of high performers that has been shown by recent findings in the supervision literature. We further propose that high performers should be high in perspective-taking, a core relational competence and a key individual factor that moderates the relationship between protégé performance and SCM. Findings from a multi-source multi-time survey (Study 1) and an online experiment (Study 2) consistently show that when high performers are low in perspective-taking, they are less likely to receive SCM. Moreover, the findings from Study 2 also show that low perspective-taking by high performers significantly reduces supervisors’ expected benefits from mentoring them, which in turn leads to the supervisors having low willingness to mentor. Our research therefore highlights the importance of taking into account the interaction between task and relational competence in understanding how protégé characteristics may influence SCM in organizational settings. The paper concludes with theoretical and practical implications

    Investigation on a 220 GHz Quasi-Optical Antenna for Wireless Power Transmission

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    This paper investigates a 220 GHz quasi-optical antenna for millimeter-wave wireless power transmission. The quasi-optical antenna consists of an offset dual reflector, and fed by a Gaussian beam that is based on the output characteristics of a high-power millimeter-wave radiation source-gyrotron. The design parameter is carried on by a numerical code based on geometric optics and vector diffraction theory. To realize long-distance wireless energy transmission, the divergence angle of the output beam must be reduced. Electromagnetic simulation results show that the divergence angle of the output beam of the 5.6 mm Gaussian feed source has been significantly reduced by the designed quasi-optical antenna. The far-field divergence angle of the quasi-optical antenna in the E plane and H plane is 1.0596° and 1.0639°, respectively. The Gaussian scalar purity in the farthest observation field (x = 1000 m) is 99.86%. Thus, the quasi-optical antenna can transmit a Gaussian beam over long-distance and could be used for millimeter-wave wireless power transmission

    Slope Failure and Landslide Detection in Huangdao District of Qingdao City Based on an Improved Faster R-CNN Model

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    To reduce the significant losses caused by slope failures and landslides, it is of great significance to detect and predict these disasters scientifically. This study focused on Huangdao District of Qingdao City in Shandong Province, using the improved Faster R-CNN network to detect slope failures and landslides. This study introduced a multi-scale feature enhancement module into the Faster R-CNN model. The module enhances the network’s perception of different scales of slope failures and landslides by deeply fusing high-resolution weak semantic features with low-resolution strong semantic features. Our experiments show that the improved Faster R-CNN model outperformed the traditional version, and that ResNet50 performed better than VGG16 with an AP value of 90.68%, F1 value of 0.94, recall value of 90.68%, and precision value of 98.17%. While the targets predicted by VGG16 were more dispersed and the false detection rate was higher than that of ResNet50, VGG16 was shown to have an advantage in predicting small-scale slope failures and landslides. The trained Faster R-CNN network model detected geological hazards of slope failure and landslide in Huangdao District, missing only two landslides, thereby demonstrating high detection accuracy. This method can provide an effective technical means for slope failures and landslides target detection and has practical implications
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