207 research outputs found

    Early warning of global change effects on catchment nutrient exports

    Get PDF
    Global change scientists seek sentinels of change. On forested landscapes, first-order catchments serve as sentinels of global stressors and their effects on downstream surface waters. Here, I explored global stressors – including climate warming, hydrological intensification, and recovery from atmospheric acidic deposition – and their effects on nutrient exports in 22-year stream chemistry records from 41 forested first-order catchments in a network of North American long-term monitoring sites. First, I used multivariate autoregressive models to establish relationships between changes in global stressors and changes in catchment nutrient exports. Second, I analyzed the residuals of these relationships to determine if there was evidence of instability in the catchment nutrient exports. I found that changes in global stressors affected the nutrient exports of these catchments but that the global stressors having the largest impacts varied geographically, and that changes in these global stressors were leading to changes in the stability of these nutrient exports

    Forms and Fragments: Enactment of Cultural Identification in an Online Community of Chinese Living Overseas

    Get PDF
    This research is an interpretive study of the dynamics of cultural identification as enacted by Chinese individuals living overseas who participate in a virtual online community known as Wenxuecity.com. The study draws on intercultural communication theories of identity proposed by Carbaugh, Collier, and Hecht, as well as on my own integrative framework for the analysis of cultural identity, to explore the self-other interaction in identity enactment, the multidimensionality of identity, and the centrality of communication in processes of identification. Through the application of a qualitative analysis of online discourse, I found three primary forms of cultural identification-- perceptual, strategic, and positional cultural identification -- that reveal how online commentators make sense of their individual and group identities. Through online discussion of a variety of topics -- from China\u27s history, East-West tensions, to academic power structures and racial hierarchies in host cultures or media stereotyping and global hegemonic relations -- and using communicative strategies like self-other comparison, advice, and ideological debate, commentators enact both a sense of group cohesiveness as well as their internal, conflictive heterogeneity. Their discourse allows for the exploration of how multiple dimensions of identity -- individuality, sociality, materiality, and spirituality -- intersect to shape the fragmentary character of cultural identification. In the particular case of the group under study, the dominant trends observed reveal that cultural identification is a process characterized by the enactment of a sense of marginalization in host societies, heightened individuality, strategic attachment to or distancing from Chinese cultural membership, and ideological divisions

    Thermal Properties of Cement-Based Composites for Geothermal Energy Applications

    Get PDF
    Geothermal energy piles are a quite recent renewable energy technique where geothermal energy in the foundation of a building is used to transport and store geothermal energy. In this paper, a structural–functional integrated cement-based composite, which can be used for energy piles, was developed using expanded graphite and graphite nanoplatelet-based composite phase change materials (CPCMs). Its mechanical properties, thermal-regulatory performance, and heat of hydration were evaluated. Test results showed that the compressive strength of GNP-Paraffin cement-based composites at 28 days was more than 25 MPa. The flexural strength and density of thermal energy storage cement paste composite decreased with increases in the percentage of CPCM in the cement paste. The infrared thermal image analysis results showed superior thermal control capability of cement based materials with CPCMs. Hence, the carbon-based CPCMs are promising thermal energy storage materials and can be used to improve the durability of energy piles

    Analysis of ocean internal waves imaged by multichannel reflection seismics, using ensemble empirical mode decomposition

    Get PDF
    Research on ocean internal waves using seismic oceanography is a frontier issue both for marine geophysicists and physical oceanographers. Images of the ocean water layer obtained by conventional processing of multichannel seismic reflection data can show the overall patterns of internal waves. However, in order to extract more information from the seismic data, new tools need to be developed. Here, we use the ensemble empirical mode decomposition (EEMD) method to decompose vertical displacement data from seismic sections and apply this method to a seismic section from the northeastern South China Sea, where clear internal waves are observed. Compared with the conventional empirical mode decomposition method, EEMD has greatly reduced the scale mixing problems induced in the decomposition results. The results obtained show that the internal waves in this area are composed of different characteristic wavelengths at different depths. The depth range of 200–1050 m contains internal waves with a wavelength of 1.25 km that are very well coupled in the vertical direction. The internal waves with a wavelength of 3 km, in the depth range of 200–600 m, are also well coupled, but in an oblique direction; this suggests that the propagation speed of internal waves of this scale changes with depth in this area. Finally, the internal waves with a wavelength of 6.5 km, observed in the depth range of 200–800 m, are separated into two parts with a phase difference of about 90◦, by a clear interface at a depth of 650 m; this allows us to infer an oblique propagation of wave energy of this scale.publishe

    Hesperidin inhibits the epithelial to mesenchymal transition induced by transforming growth factor-β1 in A549 cells through Smad signaling in the cytoplasm

    Get PDF
    Hesperidin, a natural compound, suppresses the epithelial-to-mesenchymal transition through the TGF-β1/ Smad signaling pathway. However, studies on the detailed effects and mechanisms of hesperidin are rare. The present study showed that, for A549 alveolar epithelial cells, the anti-proliferative effects of hesperidin occurred in a dose-dependent manner, with an IC50= 216.8 μM at 48 h. TGF-β1 was used to activate the Smad signaling pathway and induce the epithelial to mesenchymal transition in cells. Treatment with hesperidin or SB431542 was used for antagonism of Smad pathway activation. Hesperidin inhibited the increase in ɑ-SMA and Col1ɑ-1 and the decrease in E-cadherin in a dose-dependent manner from concentration of 20 μM to 60 μM, as assessed by both ELISA and Western blotting assays; however, there was no significant effect on cellular morphological alterations. Moreover, the Western blotting assay showed that, in the cytoplasm, hesperidin and SB431542 had no significant effect on the protein expression of Smad 2, 3, 4, or 7 as well as 2/3. However, 60 μM hesperidin and SB431542 significantly decreased p-Smad2/3 protein expression. From the above results, it is concluded that hesperidin can partly inhibit the epithelial to mesenchymal transition in human alveolar epithelial cells; the effect accounts for the blockage of the phosphorylation of Smad2/3 in the cytoplasm rather than a change in Smad protein production in the cytoplasm

    Incommensurate Phase of a Triangular Frustrated Heisenberg Model Studied via Schwinger-Boson Mean-Field Theory

    Full text link
    We study a triangular frustrated antiferromagnetic Heisenberg model with nearest-neighbor interaction J1J_{1} and third-nearest-neighbor interactions J3J_{3} by means of Schwinger-boson mean-field theory. It is shown that an incommensurate phase exists in a finite region in the parameter space for an antiferromagnetic J3J_{3} while J1J_{1} can be either positive or negtaive. A detailed solution is presented to disclose the main features of this incommensurate phase. A gapless dispersion of quasiparticles leads to the intrinsic T2T^{2}-law of specific heat. The local magnetization is significantly reduced by quantum fluctuations (for S=1 case, a local magnetization is estimated as m=0.6223m= \approx0.6223). The magnetic susceptibility is linear in temperature at low temperatures. We address possible relevance of these results to the low-temperature properties of NiGa2_{2}S4_{4}. From a careful analysis of the incommensurate spin wave vector, the interaction parameters for NiGa2_{2}% S4_{4} are estimated as, J13.8755J_{1}\approx-3.8755K and J314.0628J_{3}\approx14.0628K, in order to account for the experimental data.Comment: 9pages, 3figure

    Multi-Modal Face Stylization with a Generative Prior

    Full text link
    In this work, we introduce a new approach for artistic face stylization. Despite existing methods achieving impressive results in this task, there is still room for improvement in generating high-quality stylized faces with diverse styles and accurate facial reconstruction. Our proposed framework, MMFS, supports multi-modal face stylization by leveraging the strengths of StyleGAN and integrates it into an encoder-decoder architecture. Specifically, we use the mid-resolution and high-resolution layers of StyleGAN as the decoder to generate high-quality faces, while aligning its low-resolution layer with the encoder to extract and preserve input facial details. We also introduce a two-stage training strategy, where we train the encoder in the first stage to align the feature maps with StyleGAN and enable a faithful reconstruction of input faces. In the second stage, the entire network is fine-tuned with artistic data for stylized face generation. To enable the fine-tuned model to be applied in zero-shot and one-shot stylization tasks, we train an additional mapping network from the large-scale Contrastive-Language-Image-Pre-training (CLIP) space to a latent w+w+ space of fine-tuned StyleGAN. Qualitative and quantitative experiments show that our framework achieves superior face stylization performance in both one-shot and zero-shot stylization tasks, outperforming state-of-the-art methods by a large margin
    corecore