324 research outputs found
Inorganic Carbon Pools and Their Drivers in Grassland and Desert Soils
No full textABSTRACT Inorganic carbon is an important component of soil carbon stocks, exerting a profound influence on climate change and ecosystem functioning. Drylands account for approximately 80% of the global soil inorganic carbon (SIC) pool within the top 200 cm. Despite its paramount importance, the components of SIC and their contributions to CO 2 fluxes have been largely overlooked, resulting in notable gaps in understanding its distribution, composition, and responses to environmental factors across ecosystems, especially in deserts and temperate grasslands. Utilizing a dataset of 6011 samples from 173 sites across 224 million hectares, the data revealed that deserts and grasslands in northwestern China contain 20 ± 2.5 and 5 ± 1.3 petagrams of SIC in the top 100 cm, representing 5.5 and 0.76 times the corresponding soil organic carbon stock, respectively. Pedogenic carbonates (PIC), formed by the dissolution and re‐precipitation of carbonates, dominated in grasslands, accounting for 60% of SIC with an area‐weighted density of 3.4 ± 0.4 kg C m −2 at 0–100 cm depth, while lithogenic carbonates (LIC), inherited from soil parent materials, prevailed in deserts, constituting 55% of SIC with an area‐weighted density of 7.1 ± 1.0 kg C m −2 . Soil parent materials and elevation determined the SIC stocks by regulating the formation and loss of LIC in deserts, whereas natural acidification, mainly induced by rhizosphere processes including cation uptake and H + release as well as precipitation, reduced SIC (mainly by PIC) in grasslands. Overall, the massive SIC pool underscores its irreplaceable role in maintaining the total carbon pool in drylands. This study sheds light on LIC and PIC and highlights the critical impact of natural acidification on SIC loss in grasslands.National Key Research and Development Program of China https://doi.org/10.13039/501100012166National Natural Science Foundation of China https://doi.org/10.13039/501100001809Natural Science Foundation of Gansu Province https://doi.org/10.13039/50110000477
Building integrated photovoltaic design of nonlinear airport roof based on ruled surface fitting
No full textSolar energy is a new renewable energy. Using solar energy to generate electricity is an effective means to achieve sustainable development. The huge roof at the top of the airport is a natural interface to receive solar energy, which can be used to supply the energy needed by the airport through building integrated photovoltaic design. However, due to the curved shape of the airport roof, there are limitations in solar energy acquisition and construction of the airport roof. In this paper, the method of “ruled surface fitting-solar radiation analysis-modular unit arrangement” is used to optimize the shape of the non-linear airport roof, and convert the complex roof surface shape into a straight line with good sunlight performance and easy construction. The ruled surface can better integrate BIPV and nonlinear airport, and improve the solar power generation efficiency of the building, thus improving the sustainable performance of the building
Multi objective optimization of window to wall ratio of University Gymnasium in severe cold area by coupling natural lighting and energy consumption
No full textObjective To explore the relationship between window opening ratio and natural lighting and energy consumption of University Gymnasiums in severe cold area, and put forward optimization strategies. Methods Digital simulation technology was used to simulate the energy consumption and natural lighting of University Gymnasium window opening ratio, and the window opening scheme with natural lighting and low energy consumption was obtained. Conclusion The side window lighting should be used in the window opening scheme of small and medium-sized university gymnasiums. Within the range of experimental data, the North-South lighting is the main lighting mode, and the East-West lighting is the auxiliary
SIRT6 promotes osteogenic differentiation of mesenchymal stem cells through BMP signaling
No full textSIRT6 has been identified as an H3K9 deacetylase and a critical regulator of genome stability, telomere integrity, and metabolic homeostasis. Sirt6-deficient mice displayed dramatic phenotypes including profound lymphopenia, loss of subcutaneous fat, lordokyphosis and low bone marrow density. Here, we report that SIRT6 regulates osteogenic differentiation independent of its deacetylase activity in vitro. Further mechanistic studies showed that SIRT6 involves the cell fate determination by modulating bone morphogenetic protein (BMP) signaling. Unexpectedly, this modulation depends upon P300/CBP-associated factor (PCAF). In addition, we observed impaired SIRT6 expression in bone marrow mesenchymal stem cells and in bone sections of ovariectomized mice. Taken together, our present study provide new insights into mechanisms of SIRT6-regulated MSC function beyond its H3K9 deacetylase activity.National Natural Science Foundation of China [81570953, 81500822]; Program for New Century Excellent Talents in University from Ministry of Education [NCET-11-0026]; PKU School of Stomatology for Talented Young Investigators [PKUSS20140109]; Construction Program for National Key Clinical Specialty from National Health and Family Planning Commission of ChinaSCI(E)ARTICLE
Trust and knowledge creation: The moderating effects of legal inadequacy
No full textPurpose: This study aims to empirically investigate the effects of competence and goodwill trust on knowledge creation and the moderating effects of legal inadequacy on those relationships. Design/methodology/approach: A questionnaire survey was used to collect data from 196 research and development alliances in China. Hierarchical moderated regression was used to test the research hypotheses. Findings: We find that competence trust has a positive and linear relationship with knowledge creation while goodwill trust has an inverted U-shaped relationship with it. The results also reveal that the inverted U-shaped relationship between goodwill trust and knowledge creation is stronger when legal inadequacy is high, while the impact of competence trust on knowledge creation is not influenced by legal inadequacy. Originality/value: The findings provide insights into the distinctive effects of competence and goodwill trust on knowledge creation in partnerships, deepening current understandings of the bright and dark sides of inter-firm trust. This study also clarifies the influences of legal inadequacy on the effectiveness of competence and goodwill trust, which enhances existing knowledge about the impact of legal systems on the relationships between inter-firm trust and knoweldge management
Statistical transfer learning: A review and some extensions to statistical process control
No full textThe rapid development of information technology, together with advances in sensory and data acquisition techniques, has led to the increasing necessity of handling datasets from multiple domains. In recent years, transfer learning has emerged as an effective framework for tackling related tasks in target domains by transferring previously-acquired knowledge from source domains. Statistical models and methodologies are widely involved in transfer learning and play a critical role, which, however, has not been emphasized in most surveys of transfer learning. In this article, we conduct a comprehensive literature review on statistical transfer learning, i.e., transfer learning techniques with a focus on statistical models and statistical methodologies, demonstrating how statistics can be used in transfer learning. In addition, we highlight opportunities for the use of statistical transfer learning to improve statistical process control and quality control. Several potential future issues in statistical transfer learning are discussed.</p
How do managerial ties affect contractual governance in inter-firm cooperation?
No full textPurposeBased on social capital theory and the institutional theory, this paper aims to explain how a firm’s business ties and political ties affect contractual governance in an interfirm cooperation, and under which institutional conditions they can play a better role.Design/methodology/approachThis study tests conceptual model using questionnaire survey data collected from 227 firms in China. Hierarchical regression analysis is used to test the hypotheses.FindingsThis study finds that business ties have significant effect on contract completeness, while political ties have significant effect on contract enforcement. Moreover, these effects are contingent on some institutional factors. Market information transparency strengthens the effect of business ties on contract completeness and weakens the effect of political ties on contract completeness. Legal system completeness weakens the effect of political ties on contract enforcement.Practical implicationsThis study suggests that managers could actively and selectively use their managerial ties to enhance contractual governance in an interfirm cooperation.Originality/valueThis study adds to the current understanding of how an interfirm cooperation is shaped by the firm’s social capital derived from external network relationships and extends the research on what social antecedents affect contractual governance. Moreover, this study sheds new light on when managerial ties can play a more beneficial role in emerging economies
Probabilistic Bridge Weigh-in-Motion
No full textConventional bridge weigh-in-motion (BWIM) uses a bridge influence line to find the axle weights of passing vehicles that minimize the sum of squares of differences between theoretical and measured responses. An alternative approach, probabilistic bridge weigh-in-motion (pBWIM), is proposed here. The pBWIM approach uses a probabilistic influence line and seeks to find the most probable axle weights, given the measurements. The inferred axle weights are those with the greatest probability amongst all possible combinations of values. The pBWIM concept is tested here using a numerical model and a bridge in Slovenia. In a simulation, two hundred randomly generated 2-axle trucks pass over a 6 m long simply supported beam. In the field tests, seventy-seven pre-weighed trucks travelled over an integral slab bridge and the strain response in the soffit at mid-span was recorded. Results show that pBWIM has good potential to improve the accuracy of BWIM.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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