37 research outputs found

    The Research of Car-Following Model Based on Real-Time Maximum Deceleration

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    This paper is concerned with the effect of real-time maximum deceleration in car-following. The real-time maximum acceleration is estimated with vehicle dynamics. It is known that an intelligent driver model (IDM) can control adaptive cruise control (ACC) well. The disadvantages of IDM at high and constant speed are analyzed. A new car-following model which is applied to ACC is established accordingly to modify the desired minimum gap and structure of the IDM. We simulated the new car-following model and IDM under two different kinds of road conditions. In the first, the vehicles drive on a single road, taking dry asphalt road as the example in this paper. In the second, vehicles drive onto a different road, and this paper analyzed the situation in which vehicles drive from a dry asphalt road onto an icy road. From the simulation, we found that the new car-following model can not only ensure driving security and comfort but also control the steady driving of the vehicle with a smaller time headway than IDM

    Distributions of fossil and extant mammals in China

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    01 Appendix_occurrence_data; 02 Appendix_community_data_Family; 03 Appendix_community_data_GenusAim Historical changes in community structure underlie modern spatial diversity patterns, but few empirical studies have focused on the variation in the community composition of fossil assemblages at large spatiotemporal scales. We wanted to investigat how the spatial differentiation of mammal communities changed in China throughout the Cenozoic in response to tectonic uplift and paleoclimatic changes and explore the timing of the emergence of the modern spatially structured faunas. Location China Time period Cenozoic (from 65 Ma to the present) Major taxa studied Terrestrial mammals Methods We used a compiled database of the distributions of fossil and extant mammals to compare the multiple-site beta diversity among families and genera within six time intervals of the Cenozoic using Sørensen dissimilarity (βsor) and Simpson dissimilarity (βsim). To investigate the timing of the emergence of the modern spatially structured faunas, we applied hierarchical clustering and non-metric multidimensional scaling ordination based on pairwise βsim among seven zoogeographical regions within each time slice. Results The multiple-site beta diversity at the family level displayed hump-shaped changes during the Cenozoic, and it peaked in the Eocene and gradually decreased towards the present. However, the genus-level multiple-site beta diversity remained rather constant throughout the Cenozoic. Pronounced variations in the relationships among the zoogeographical regions were revealed in both the cluster analyses and ordinations. The modern spatial structure of mammal faunas at the family level was broadly similar to those observed in the Pliocene and Pleistocene. Main conclusions The spatial differentiation of mammal faunas in China dates back to the Eocene and pre-dates the formation of modern topography and climate. Throughout the Cenozoic, the spatial structure of mammal faunas was reorganized by an interplay of the uplift of the Tibetan Plateau, the emergence of the monsoon system and global macroevolutionary processes. The modern relationships among zoogeographical regions at the family level were established in the Pleistocene

    Data from: Cenozoic evolution of beta diversity and a Pleistocene emergence for modern mammal faunas in China

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    Aim Historical changes in community structure underlie modern spatial diversity patterns, but few empirical studies have focused on the variation in the community composition of fossil assemblages at large spatiotemporal scales. We wanted to investigat how the spatial differentiation of mammal communities changed in China throughout the Cenozoic in response to tectonic uplift and paleoclimatic changes and explore the timing of the emergence of the modern spatially structured faunas. Location China Time period Cenozoic (from 65 Ma to the present) Major taxa studied Terrestrial mammals Methods We used a compiled database of the distributions of fossil and extant mammals to compare the multiple-site beta diversity among families and genera within six time intervals of the Cenozoic using Sørensen dissimilarity (βsor) and Simpson dissimilarity (βsim). To investigate the timing of the emergence of the modern spatially structured faunas, we applied hierarchical clustering and non-metric multidimensional scaling ordination based on pairwise βsim among seven zoogeographical regions within each time slice. Results The multiple-site beta diversity at the family level displayed hump-shaped changes during the Cenozoic, and it peaked in the Eocene and gradually decreased towards the present. However, the genus-level multiple-site beta diversity remained rather constant throughout the Cenozoic. Pronounced variations in the relationships among the zoogeographical regions were revealed in both the cluster analyses and ordinations. The modern spatial structure of mammal faunas at the family level was broadly similar to those observed in the Pliocene and Pleistocene. Main conclusions The spatial differentiation of mammal faunas in China dates back to the Eocene and pre-dates the formation of modern topography and climate. Throughout the Cenozoic, the spatial structure of mammal faunas was reorganized by an interplay of the uplift of the Tibetan Plateau, the emergence of the monsoon system and global macroevolutionary processes. The modern relationships among zoogeographical regions at the family level were established in the Pleistocene

    Characterizing semen abnormality male infertility using non-targeted blood plasma metabolomics.

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    Semen abnormality (SA) male infertility has become a worldwide reproductive health problem. The invasive tests (e.g., testicular biopsy) and labor-intensive methods of semen collection severely inhibit diagnosis of male infertility. In addition, the pathogenesis and biological interpretation of male infertility are still obscure. In this report, a total of 84 semen abnormality (SA) patients, diagnosed as teratozoospermia (TE, n = 21), asthenozoospermia (AS, n = 23), oligozoospermia (OL, n = 20), azoospermia (AZ, n = 20), and age-matched healthy controls (HC, n = 29) were analyzed by GC-MS for discrimination analysis and discovery of potential biomarkers. Twenty-three biomarkers were obtained by multivariate statistical method (partial least squares-discriminant analysis, PLS-DA) and univariate statistical method (analysis of variance, ANOVA) with comparisons of TE versus HC, AS versus HC, OL versus HC and AZ versus HC. Based on those biomarkers, the most relevant pathways were mainly associated with the metabolism of carbohydrates, amino acids, and lipids. The principal metabolic alternations in SA male infertility included increased levels of energy-related metabolisms, such as tricarboxylic acid cycle, pyruvate metabolism, glyoxylate and dicarboxylate metabolism, glycine, serine, threonine metabolism and saturated fatty acid metabolism. Furthermore, increased levels of glutathione metabolism were related to oxidative stress. Finally, decreased levels of arginine and proline metabolism and inositol phosphate metabolism were observed. In conclusion, blood plasma metabolomics is powerful for characterizing metabolic disturbances in SA male infertility. From metabolic pathway analysis, energy production, oxidation stress and the released enzyme during spermatogenesis take the primary responsibilities for SA male infertility

    Trade‐offs between economic development and biodiversity conservation on a tropical island

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    Resolving trade-offs between economic development and biodiversity conservation needs is crucial in currently developing countries and in particularly sensitive systems harboring high biodiversity. Yet, such a task is challenging because human activities have complex effects on biodiversity. We assessed the effects of intense economic development on Hainan Island (southern China) on different components of biodiversity. This highly biodiverse tropical island has undergone extensive economic development and conversion of forest to agriculture and urban area. We identified 3 main transformation areas (low, medium, and high transformation) based on land-use, local-climate, and economic changes across 145 grids (10 × 10 km), and estimated changes in avian biodive6rsity from 1998 to 2013. We recorded ongoing taxonomic biotic homogenization throughout the island. Differences between traditional and directional alpha diversity decreased by 5%. Phylogenetically clustering increased by 0.5 points (W = 7928, p < 0.01), and functional overdispersion increased by 1 point (W = 16,411, p < 0.01). Initial taxonomic, phylogenetic, and functional scores correlated negatively with changes in these scores across all transformation areas (all ps < 0.01). At the local scale, economic and environmental indicators showed complex and divergent effects across transformation areas and biodiversity components. These effects were only partially ameliorated in an ecological function conservation area in the mountainous central part of the island. We found complex effects of economic development on different biodiversity dimensions in different areas with different land uses and protection regimes and between local and regional spatial scales. Profound ecosystem damage associated with economic development was partially averted, probably due to enhanced biodiversity conservation policies and law enforcement, but not without regional-scale biotic homogenization and local-scale biodiversity loss

    Altered Long Noncoding RNA and Messenger RNA Expression in Experimental Intracerebral Hemorrhage - a Preliminary Study

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    Background/Aims: Functional recovery in the chronic phase is a difficult problem in intracerebral hemorrhage (ICH) treatment. Long noncoding RNAs (lncRNAs) are demonstrated to be involved in central nervous system (CNS) disorders. However, the roles of lncRNAs in post-ICH injury and repair are poorly understood, especially those that may be attributed to long-term neurological deficit. The present study depicted the lncRNA and messenger RNA (mRNA) profile by microarray at late stage after an experimental ICH. Methods: LncRNA and mRNA microarray was used to first identify differentially expressed genes. Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to determine bio-functions and signaling pathways, with which differentially expressed genes are most closely related. Quantitative real-time polymerase chain reaction (PCR) was used to validate the results of microarray. Finally, the lncRNA-mRNA co-expression network was constructed to find the interaction of genes. Results: A total of 625 differentially expressed lncRNAs and 826 expressed mRNAs were identified. Altered genes were enriched in mitochon-drial matrix, G-protein coupled receptor signaling pathway, and olfactory transduction, which may be associated with ICH-induced pathophysiologic changes in the long term. A co-expression network profile based on 5 validated differentially expressed lncRNAs and 205 interacted mRNAs was composed of 210 nodes and 298 connections. Conclusion: Mitochondrial matrix, reduced G-protein coupled receptor activity, and impaired olfactory transduction may be involved in the sequelae following ICH. Further, these dysregulated lncRNAs and mRNAs may be the promising therapeutic targets to overcome obstacles in functional recovery following ICH

    Gancao (Glycyrrhizae Radix) provides the main contribution to Shaoyao-Gancao decoction on enhancements of CYP3A4 and MDR1 expression via pregnane X receptor pathway in vitro

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    Abstract Background Chinese herbal formula Shaoyao Gancao decoction (SGD) is often used as an adjuvant with chemotherapeutic agents to treat cancer. Due to the herb-drug interactions, the alternations of drug metabolic enzyme and drug transporters induced by SGD deserve to be explored. We aimed to investigate the effect of SGD on the pregnane X receptor (PXR)-mediated transcriptional regulation of cytochrome P450 3A4 (CYP3A4) and drug transporter multidrug resistance protein 1 (MDR1) in vitro. Besides, we assessed the contribution of constituent herbs to SGD on the regulation of CYP3A4 and MDR1. Methods The dual luciferase reporter gene system containing the hPXR expression plasmid and the reporter gene plasmid of CYP3A4 or MDR1 was co-transfected to HepG2 and Caco2 cells. Luciferase activities were determined using a Dual-luciferase reporter assay kit. The gene expression of CYP3A4 and MDR1 in the hPXR-transfected LS174T cells were assessed by real-time qPCR. Finally, the contribution of constituent herbs from SGD was evaluated. Results SGD, Shaoyao and Gancao concentration-dependently increased promoter activities of CYP3A4 and MDR1 in vitro. Moreover, SGD, Shaoyao and Gancao up-regulated CYP3A4 and MDR1 mRNA in hPXR-transfected LS174T cells. As the herbal constituent of SGD, Gancao possesses significantly higher levels of metabolic enzyme and drug transporters compared with Shaoyao. Conclusion SGD tends to enhance CYP3A4 and MDR1 expression via PXR pathway, especially Gancao provides the main contribution. This study highlights a potential in vitro mechanism for SGD on the regulation of drug metabolic enzymes and drug transporters
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