1,178 research outputs found
Regulating Labour Relations in China : The Challenge of Adapting to the Socialist Market Economy
This paper examines the new Labour Law of the PRC, effective January 1, 1995, in the light of current and historical conditions of labour relations in China. Provisions regarding the labour contract system and dispute resolution are discussed in greater detail. Issues related to the introduction of collective bargaining and to the relationship between trade unions and the Communist Party are also examined. In their overall assessment, the authors recognize the potential significance of the Labour Law as a major step towards the legal protection of workers' rights, but point out that its effectiveness could be undermined by the preeminent policy of economic growth, by concerns about political control, and by obstacles to full implementation.Cet article analyse la nouvelle Loi de la RPC sur le travail, entrée en vigueur le 1er janvier 1995, dans le contexte historique et actuel des relations de travail en Chine. Les auteurs accordent une attention particulière aux dispositions relatives au contrat de travail et au règlement des différends. Ils examinent également les difficultés soulevées par l'introduction des conventions collectives dans les entreprises chinoises, et par les relations entre les syndicats et le Parti communiste. Tout en reconnaissant, dans leur appréciation globale de la loi, qu'elle pourrait marquer une étape importante vers la protection juridique des droits des travailleurs, ils signalent que sa portée réelle pourrait être amoindrie par la prépondérance de la politique de croissance économique, par le souci de préserver le contrôle politique et par des difficultés pratiques de mise en oeuvre
Using modern and fossil pollen data for climate and human influence reconstructions in China
Assessing the numerical relationships among pollen spectra, human influence and climate is a critical prerequisite for obtaining reliable and robust pollen-based quantitative reconstructions for past climatic variations and human-induced environmental changes. Here, modern pollen data from small river catchments in human-influenced mountainous ecosystems of northern China are collected to investigate the pollen/vegetation/land-use relationships. The effects of human influence index (HII) in comparison with key climate variables on influencing modern pollen distribution are evaluated using a continental-scale dataset. The importance of different climate variables accounting for modern pollen distribution is quantified for identifying the determinant variables that can be reconstructed in different bioclimatic regions of China. Furthermore, pollen-based calibration models for HII and climate parameters are developed and applied to a set of fossil pollen data for quantitative human influence and climate reconstructions. In addition, the bias caused by long-term and intensive human influence on vegetation in quantitative pollen-based palaeoclimatic reconstructions is examined, and pollen-based climate reconstructions are used to validate the reliability of climate model simulations.
The results reveal that pollen assemblages from surface sediment samples in the Tuoliang and Qipanshan catchments from northern China are dominated by Artemisia, Chenopodiaceae, Pinus and Selaginella sinensis. Pollen types indicative of human activities such as Cerealia-type are common but not abundant. Artemisia and Chenopodiaceae percentages decline with decreasing altitude, whereas Pinus and S. sinensis percentages increase, suggesting that saccate Pinus pollen and S. sinensis spores can be transported further than non-saccate pollen types and that pollen sorting is taking place over water transportation. There is a positive linear relationship between percentages of Cerealia-type pollen and proportions of farmland, whereas correlation between percentages of trees, shrubs and herbs pollen and proportions of woodland, scrubland and grassland respectively is poor. This can be attributed to the differences in pollen productivity, deposition and dispersal. These findings may provide the basis for a modeling approach to reconstruct past land-cover changes at small catchment scale in northern China.
The effects of HII on accounting for modern pollen distribution are smaller than annual precipitation (PANN) or annual average temperature (TANN) in most regions of China, with the exception of east-central China that has a significant pollen–HII relationship. The quantified importance of six climate variables (PANN; TANN; actual/potential evapotranspiration ratio, Alpha; mean temperature of the warmest month, MTWA; mean temperature of the coldest month, MTCO; annual sum of the growing degree days above 5 °C, GDD5) for the geographical distribution of modern pollen data differs among regions in China. Hydrological variables are more important than temperature-related variables in north-western and -eastern China and the Tibetan Plateau, whilst temperature-related variables are dominant in east-central and southern China. This suggests that the critical climate variables which can be optimally reconstructed from pollen data vary regionally in China. These regional differences are common to other large-scale surface pollen datasets and need to be taken into considerations in pollen-based climate reconstructions.
The calibration models for HII, PANN and TANN show good statistical performances and are applied to a fossil pollen sequence from Lake Tianchi in east-central China. The inferred HII increases abruptly at 1100 cal. yr BP and remains high until present-day. Correspondingly, the reconstructed PANN shows a sudden decrease since 1100 cal. yr BP, whereas TANN displays an increase. However, other independent palaeoclimatic records mostly contradict the reconstructed climatic trends for the last 1100 years, suggesting that the Tianchi climate reconstructions for this period are biased by the intensification of human influence. This bias probably occurs in other palaeoclimatic reconstructions using pollen data from other regions where human impact on vegetation is also intensive and long-lasting. The calibration models for the summer monsoon precipitation (Pjja) also exhibit good predictive performances and are applied to a set of fossil pollen data from monsoonal China. The Holocene Pjja reconstructions from northern China are stacked to one record, showing that Pjja increases since 9500 cal. yr BP, reaches the maximum at 7000–4000 cal. yr BP, and falls down to present-day. The reconstructions are compared with Pjja simulations from the Kiel Climate Model (KCM). The model output and reconstructions are different for the early-Holocene for which the model suggests higher Pjja. The simulated Pjja changes for the Holocene summer monsoon maximum (HSMM) are lower than the reconstructed changes. The increasing or decreasing Pjja trends before or after the HSMM are more pronounced in the reconstructions than in the model results. Other palaeoclimatic data show substantial Holocene monsoon precipitation changes. This suggests that the KCM underestimates the magnitude of the summer monsoon precipitation changes.
The results obtained in this work highlight the necessity for critically assessing the modern pollen/human-influence/climate relationships at various spatial scales and can be used to improve the correctness and robustness of pollen-based climate and human influence reconstructions in China and other regions of the world with large-scale surface pollen datasets. The pollen-based calibration models and their forthcoming applications can be employed to further quantitatively explore the past environmental changes and climatic dynamics and to validate the accuracy of climate model output
(E)-N′-[4-(DimethylÂamino)ÂbenzylÂidene]-4-methylÂbenzohydrazide methanol monosolvate
In the title compound, C17H19N3O·CH3OH, the hydrazone molÂecule exists in a trans geometry with respect to the methylÂidene unit and the dihedral angle between the two substituted benzene rings is 42.6 (2)°. In the crystal, the components are linked through N—H⋯O and O—H⋯O hydrogen bonds, forming [100] chains of alternating hydrazone and methanol molÂecules
Thermal stability, pH dependence and inhibition of four murine kynurenine aminotransferases
<p>Abstract</p> <p>Background</p> <p>Kynurenine aminotransferase (KAT) catalyzes the transamination of kynunrenine to kynurenic acid (KYNA). KYNA is a neuroactive compound and functions as an antagonist of alpha7-nicotinic acetylcholine receptors and is the only known endogenous antagonist of N-methyl-D-aspartate receptors. Four KAT enzymes, KAT I/glutamine transaminase K/cysteine conjugate beta-lyase 1, KAT II/aminoadipate aminotransferase, KAT III/cysteine conjugate beta-lyase 2, and KAT IV/glutamic-oxaloacetic transaminase 2/mitochondrial aspartate aminotransferase, have been reported in mammalian brains. Because of the substrate overlap of the four KAT enzymes, it is difficult to assay the specific activity of each KAT in animal brains.</p> <p>Results</p> <p>This study concerns the functional expression and comparative characterization of KAT I, II, III, and IV from mice. At the applied test conditions, equimolar tryptophan with kynurenine significantly inhibited only mouse KAT I and IV, equimolar methionine inhibited only mouse KAT III and equimolar aspartate inhibited only mouse KAT IV. The activity of mouse KAT II was not significantly inhibited by any proteinogenic amino acids at equimolar concentrations. pH optima, temperature preferences of four KATs were also tested in this study. Midpoint temperatures of the protein melting, half life values at 65°C, and pKa values of mouse KAT I, II, III, and IV were 69.8, 65.9, 64.8 and 66.5°C; 69.7, 27.4, 3.9 and 6.5 min; pH 7.6, 5.7, 8.7 and 6.9, respectively.</p> <p>Conclusion</p> <p>The characteristics reported here could be used to develop specific assay methods for each of the four murine KATs. These specific assays could be used to identify which KAT is affected in mouse models for research and to develop small molecule drugs for prevention and treatment of KAT-involved human diseases.</p
A thermal behavior of low-substituted hydroxyethyl cellulose and cellulose solutions in NaOH-water
The articles belonging to the special issue are open access, all published articles are freely available online.International audienceHydroxyethyl cellulose (HEC) with low molar substitution has better solubility in 8%NaOH-water solution than pure cellulose. The thermal behavior of ternary HEC/NaOH/water mixtures was investigated by DSC, and the results are compared with those of cellulose/NaOH/water solutions, aiming at providing better understanding about cellulose dissolution mechanism in NaOH-water. At low polymer concentrations and below 0°C, HEC and cellulose solutions exhibit a similar thermal behavior with ice, eutectic and/or melting and recrystallization peaks, showing that the overall interactions between NaOH, water and cellulose or HEC are identical. However, when the concentration increases above 2%, the eutectic peak of HEC solutions disappeared, leaving only the ice peak, which is different from previous results for cellulose where the disappearance of the eutectic peak was related to the maximum solubility of cellulose (around 8 wt%). This implies that the dissolution behavior of HEC in NaOH solution is changed due to possible changes of chain flexibility and/or increased attractions to water caused by the hydrophilic hydroxyethyl groups. The melting and recrystallization peaks visible only at low concentrations of HEC or cellulose in solution also support the conclusion that dissolution of cellulose and HEC at low concentrations bears features which are not yet understood
Thermal characteristics analysis of the slide carriage system of the X axis based on the thermal contact resistance and the environment temperature change
In the electrical discharge machine (EDM), the slide carriage system of the X axis connects the lathe bed and the ram of the Y axis, its thermal-deformation has a directly effect on machining precision. Based on Solid-works and ANSYS Workbench software to build the finite element model (FEM) of the slide carriage system, the heat generation of the motor on the Y axis, and the frictional heat of the bearing and guide as the main thermal source, there are two cases: applied and no contact thermal resistance (TCR) as the thermal-structure coupling deformation analysis. Established a model of the natural convection heat transfer coefficient with the temperature-change according to the actual measured the temperature curve of workshop and mathematical logarithm principle. The analysis told us that: in the thermal analysis of precision mechanical equipment, heat source comes from the external environment temperature and motor heat production, at the same time, the contact thermal resistance and the natural convection heat transfer coefficient with the temperature-change for the thermal characteristics of the equipment will make an important influence
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