191 research outputs found

    Reduced scale model test on cable membrane roof of Shangai Expo Central Axis

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    p. 2008-2018In this paper a reduced scale model test on cable membrane roof of Shanghai Expo Central Axis is introduced. The membrane pre-stresses, cable forces and membrane geometry at the initial state are carefully inspected. Numerical form-finding analysis is also carried out and its result is compared with the inspecton. The behaviors of the membrane roof under breaking of cables are observed. Test proves the practicability of the project in aspects of system safety, analysis and inspection.Zhang, Q.; Yang, Z.; Chen, L.; Tang, H.; Zhu, B. (2010). Reduced scale model test on cable membrane roof of Shangai Expo Central Axis. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/718

    Research Progress of the International Carbon Tariff: A Review

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    Under the constraints of the target peak carbon dioxide emissions and carbon neutrality, how the international carbon tariff can be levied have become an important question for scholars and research institutions all over the world. This paper aimed to comprehensively sort the relevant literature on the Carbon Border Adjustment Mechanism from an economic perspective. Based on defining the concept connotation and extension of carbon tariff, we summarized and determined the price mechanism, institutional mechanism, and coordination mechanism of the carbon tariff, and analyzed the impact of carbon tariff on the economic environment and other fields. Further, this paper makes an international comparison of the existing reasonably operable carbon tariff, points out the focus and direction of the next research, and strives to provide valuable experience and theoretical reference for the innovative practice of building the international Carbon Border Adjustment Mechanism. Keywords: carbon tariff, border tax adjustment, connotation and extension, mechanism design, economic impac

    Why the processing of repeated targets are better than that of no repetition: evidence from easy-to-difficult and difficult-to-easy switching situations

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    Background: Previous studies have found that the processing of repeated targets are easier than that of non-repetition. Although several theories attempt to explain this issue, the underlying mechanism still remains uncovered. In this study, we tried to address this issue by exploring the underlying brain responses during this process. Methods: Brain activities were recorded while thirty participants performing a Stroop task (Chinese version) in the MRI scanner. Using pseudo-random strategies, we created two types of switching conditions (easy-to-difficult; difficult-to-easy) and relevant repeating conditions. Results: The results show that, in difficult-to-easy switching situation, higher brain activations are found in left precuneus than repeating ones (the precuneus is thought related with attention demands). In easy-to-difficult switching conditions, higher brain activations are found in precuneus, superior temporal gyrus, posterior cingulate cortex, and inferior frontal gyrus than repeating trials (most of these regions are thought related with executive function). No overlapping brain regions are observed in con_CON and incon_INCON conditions. Beta figures of the survived clusters in different conditions, correlations between brain activations and switch cost were calculated. Conclusions: The present study suggests that the feature that response time in switching trials are longer than that in repeating trials are caused by the extra endeavors engaged in the switching processes

    Follow-up of patients with COVID-19 by the Delta variant after hospital discharge in Guangzhou, Guandong, China

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    The B.1.617.2 (Delta) variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has contributed to a new increment in cases across the globe. We conducted a prospective follow-up of COVID-19 cases to explore the recurrence and potential propagation risk of the Delta variant and discuss potential explanations for the infection recurrence. A prospective, non-interventional follow-up of discharged patients who had SARS-CoV-2 infections by the Delta variant in Guangdong, China, from May 2021 to June 2021 was conducted. The subjects were asked to complete a physical health examination and undergo nucleic acid testing and antibody detection for the laboratory diagnosis of COVID-19. In total, 20.33% (25/123) of patients exhibited recurrent positive results after discharge. All patients with infection recurrence were asymptomatic and showed no abnormalities in the pulmonary computed tomography. The time from discharge to the recurrent positive testing was usually between 1-33 days, with a mean time of 9.36 days. The cycle threshold from the real-time polymerase chain reaction assay that detected the recurrence of positivity ranged from 27.48 to 39.00, with an average of 35.30. The proportion of vaccination in the non-recurrent group was higher than that in the recurrently positive group (26% vs. 4%; χ2 = 7.902; P < 0.05). Two months after discharge, the most common symptom was hair loss and 59.6% of patients had no long-term symptoms at all. It is possible for the Delta variant SARS-CoV-2 patients after discharge to show recurrent positive results of nucleic acid detection; however, there is a low risk of continuous community transmission. Both, the physical and mental quality of life of discharged patients were significantly affected. Our results suggest that it makes sense to implement mass vaccination against the Delta variant of SARS-CoV-2

    RNAi-directed downregulation of OsBADH2 results in aroma (2-acetyl-1-pyrroline) production in rice (Oryza sativa L.)

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    <p>Abstract</p> <p>Background</p> <p>Aromatic rice is popular worldwide because of its characteristic fragrance. Genetic studies and physical fine mapping reveal that a candidate gene (<it>fgr</it>/<it>OsBADH2</it>) homologous to <it>betaine aldehyde dehydrogenase </it>is responsible for aroma metabolism in fragrant rice varieties, but the direct evidence demonstrating the functions of <it>OsBADH2 </it>is lacking. To elucidate the physiological roles of <it>OsBADH2</it>, sequencing approach and RNA interference (RNAi) technique were employed to analyze allelic variation and functions of <it>OsBADH2 </it>gene in aroma production. Semi-quantitative, real-time reverse transcription-polymerase chain reaction (RT-PCR), as well as gas chromatography-mass spectrometry (GC-MS) were conducted to determine the expression levels of <it>OsBADH2 </it>and the fragrant compound in wild type and transgenic <it>OsBADH2</it>-RNAi repression lines, respectively.</p> <p>Results</p> <p>The results showed that multiple mutations identical to <it>fgr </it>allele occur in the 13 fragrant rice accessions across China; <it>OsBADH2 </it>is expressed constitutively, with less expression abundance in mature roots; the disrupted <it>OsBADH2 </it>by RNA interference leads to significantly increased 2-acetyl-1-pyrroline production.</p> <p>Conclusion</p> <p>We have found that the altered expression levels of <it>OsBADH2 </it>gene influence aroma accumulation, and the prevalent aromatic allele probably has a single evolutionary origin.</p

    Water-gas masking effect of the primary active sites in coal and room temperature oxidation of coal after desorption

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    The oxidation of coal at room temperature provides the initial heat source for spontaneous coal combustion (CSC). In the CSC theoretical study, exploring the active substances in coal that can be oxidized at room temperature is a complex problem. Previous thermal decomposition experiments have found that coal after pyrolysis contains active sites that can exist stably in inert gases and be oxidized at room temperature. Thus it is speculated that there may also be primary active sites that are forced to be stored under inert media in coal. In order to explore the primary active sites of coal, the vacuum drying technology is applied. Based on that, the water in the raw coal can reach the boiling point under the low-temperature environment of negative vacuum pressure to complete the removal of water and gas. Under different experimental conditions (coal, desorption temperature, oxidation temperature, particle size), the cyclic oxidation online monitoring technology is used to design and implement the room temperature oxidation experiment of the desorbed coal samples. At the same time, the reaction mechanism is analyzed by the corresponding low-temperature nitrogen adsorption, XPS, ESR experiments. After vacuum desorbed, the oxidation experiments under cyclic conditions show that the massive gaseous oxidation products such as CO and CO2 will be formed in the process of raw oxidation at room temperature, and the gases appear and accumulate soon after oxygen is introduced, which proves that coal oxidation can occur at room temperature. The room temperature oxidation experiment after the desorption of raw coal indicates that there are a large number of active sites affected by water-gas masking in the raw coal. They are unable to undergo the oxidation exothermic processes, while the coal after the desorption of water and gas under negative pressure exposes massive active sites and forms a channel conducive to oxygen transport and reaction, which rapidly occur oxidation exothermic phenomenon and lead to the rise of coal temperature. Therefore, the active structure leading to the spontaneous warming of the raw coal is found, and the experiments extend the view of room temperature oxidation of the active sites from the particular case state of the pyrolysis to the general state. From the comparison of gas product generation, it can be seen that CO, which is not easy to be adsorbed by pores, is produced quickly at the moment of contact between the primary active site and oxygen. Therefore, it can be concluded that CO is more suitable as an intuitive gas evaluation index of the concentration of the active sites compared with CO2. The room temperature oxidation of the primary active sites of coal helps reveal the mechanism of coal spontaneous combustion and provides a solution to the problem of spontaneous combustion during gas extraction in high-gas mines and the problem of CO over-limit in low-rank coal mines

    Analysis of the association between testosterone and cardiovascular disease potential risk factor apolipoprotein B in adult males without cancer: national health and nutrition examination survey 2011-2016

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    BackgroundOver the years, there has been extensive exploration of the association between testosterone and lipid profiles, yet the precise mechanisms underlying their interaction remain incompletely elucidated. Similarly, there is a dearth of research on the correlation between serum apolipoprotein B (apoB) and serum total testosterone (TT), particularly within specific populations.MethodsWe conducted a cross-sectional study to assess the relationship between serum TT concentration and serum apoB concentration. Using the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016, we employed weighted generalized linear models, weighted univariate, weighted multivariate analysis, and smooth curve fitting to assist in exploring the relationship between serum TT and apoB. Serum apoB concentration served as the independent variable, and serum TT concentration as the dependent variable. ApoB was divided into four quartiles—Q1 (&lt;0.7g/L, N=691), Q2 (≥0.7g/L to &lt;0.9g/L, N=710), Q3 (≥0.9g/L to &lt;1.1g/L, N=696), and Q4 (≥1.1g/L, N=708)—thereby further solidifying the stable association between the two. Additionally, the application of smooth curve fitting will contribute to a more detailed elucidation of the specific relationship between serum TT concentration and serum apoB concentration under different factors (Drinking, Smoke, Diabetes, Hypertension, and High cholesterol level.).ResultsThe results indicate a negative correlation between serum TT concentration and apoB concentration (β=-113.4; 95% CI: -146.6, -80.2; P&lt;0.001). After adjusting for confounding variables, the negative correlation between apoB concentration and TT concentration remains significant (β=-61.0; 95% CI: -116.7, -5.2; P=0.040). When apoB concentration was converted from a continuous variable to a categorical variable (quartiles: Q1&lt;0.7g/L; Q2:≥0.7g/L to&lt;0.9g/L; Q3:≥0.9g/L to &lt;1.1g/L; Q4: ≥1.1g/L), TT level of participants in the highest quartile (≥1.1g/L) was -47.2 pg/mL (95% CI: -91.2, -3.3; P=0.045) lower than that in the lowest quartile (&lt;0.7g/L). The smooth curve fitting diagram revealed differences in the relationship between TT concentration and apoB among individuals with different cardiovascular disease (CVD) risk factors.ConclusionsThis study elucidates a robust inverse correlation between serum TT concentration and apoB concentration, maintaining statistical significance even upon adjustment for confounding factors. These findings present a promising avenue for addressing the prevention and treatment of low testosterone and CVD
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