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It is certain that globally the troposphere has warmed since the industrial revolution because of the greenhouse gas emissions. The water vapour content of air increases as the climate warms. However, there is nonsignificant long‐term trend in global‐scale precipitation. This study aims to investigate the sources of the uncertainty of the long‐term precipitation trend under global warming through the water cycle. The data of the historical simulations (1850–2005) from 30 CMIP5 models are used in the estimate. The p‐value is utilized to indicate the significance of the long‐term trend of the water‐vapour‐related variable in the water cycle as well as the air temperature near surface and at the condensation level. For each variable, the p‐value is calculated for each of the grid points. The overall spatial distribution patterns of the p‐values are compared between two variables that linked directly, and a point‐to‐point comparison is also performed to the two fields. Results show that over the globe, the near‐surface specific humidity increases significantly at most of the grid points while the increase of the specific humidity at the condensation level is significant at some, and, however, the long‐term trend of the relative humidity at the condensation level is majorly nonsignificant. This suggests that as assessed from the global grid points, the uncertainty of the long‐term trend of the water‐vapour‐related variable enlarges substantially in the process of condensation, and modestly in the process of the transport of water vapour. Therefore, the uncertainty of the long‐term precipitation trend under global warming is mainly attributed to the condensation and slightly due to the transport of water vapour. The results obtained from the 30 models are consistent with each other, which supports the reliability of the conclusion. [ABSTRACT FROM AUTHOR]

In shock models, induction of endotoxin tolerance (ET) is known to have a protective effect. The present study was designed to explore if ET is effective in protecting lungs from reperfusion injury. Twelve foxhounds were used as experimental animals. After a left thoracotomy, the left hilum was clamped for 3 h, followed by 8 h of reperfusion. In the treatment group (ET, n = 6), dogs were pretreated with incremental daily endotoxin doses of up to 60 [micro]g/kg on day 6. The ischemia and reperfusion experiment was carried out on day 9. Control group animals (n = 6) were not subjected to endotoxin. Afar 8 h of observation, functional parameters of the reperfused lung of the ET and the control group were statistically different (P < 0.05) with respect to P[O.sub.2] [ET vs. control: 172.7 [+ or -] 12.9 vs. 66.1 [+ or -] 7.2 (SE) mmHg], compliance (16.0 [+ or -] 1.2 vs. 8.3 [+ or -] 1.0 ml/0.1 kPa), and the wet-to-dry ratio (9.4 [+ or -] 0.8 vs. 16.7 [+ or -] 1.2). After 3 h of warm ischemia and 8 h of reperfusion, pulmonary function and lung water content improved in the endotoxin-tolerant group. ischemia-reperfusion; acute respiratory distress syndrome; surfactant; lipopolysaccharide

The thermal forcing of the Tibet Plateau (TP) causes circulation anomalies that may affect the East Asian monsoon. Hence, summer precipitation in China has a close relation to the previous heat source over TP. The saturation of the atmosphere is the precondition of precipitation, so variations of vapour and temperature adjust the generation of precipitation synergistically. The heating of TP exerts impacts on summer precipitation in China, essentially, through modulating vapour and temperature. The goal of this study is to identify whether the variations of temperature or vapour dominate in the end. Besides, according to the heating characteristics over TP, a more accurate area of spring (March–May) heat source is chosen to indicate the midsummer (July) precipitation in China. The configuration of contributions of temperature and vapour can be divided into two cases. One is that vapour and temperature both increase or decrease, so they play inverse roles. It is easy to find the dominant element in this circumstance. The other is that vapour and temperature have concurrent effects. In this case, their significances need to be further compared. The method based on the linkage of the precipitation and relative humidity is used to quantitatively compare the effects of temperature and vapour. The results are robust and can complement the qualitative analysis with circulations and temperature. In years that there is intense heating on west TP, the Yangtze River basin (YZRB) is controlled by more vapour transport from oceans. The downstream of the Yellow River basin (YLRB) is affected by the dry and cold northerly winds. Dominance analysis shows that vapour general plays a more important role in two major river basins. Maybe not exactly coincide with someone's envision, not all the places are dominated by the vapour. Around northeast China, temperature contributes little more than vapour. [ABSTRACT FROM AUTHOR]

The spatial inhomogeneity of air pressure drives the atmospheric circulation. The interannual variation of the pressure can be affected by both air temperature and density. The goal of this study is to identify, for the near‐surface air, whether the variation of the density or temperature is more important in the interannual variation of the pressure. The physical relation of the pressure (P) with density (D) and temperature (T), denoted as P = D ⋅ T for simplicity, is nonlinear. To be convenient for estimating the relative importance, a normalized linear regression is used to fit the relation, which is finally written as P = AD + BT. Tests show that the linear fitting is robust; it is perfect everywhere in the globe. Because of the normalizations, the D and T are in magnitude of 1, but can be positive or negative. Derivations and calculations indicate that the coefficients A and B are both positive. What they reflect are the partial correlations of the pressure with the D and T, which are both equal to 1 across the entire field. For the normalized fitting, the A and B can be used to estimate the contributions of the D and T to the variation of the pressure. The linear fitting method can provide quantitative results for the dominance. The original nonlinear relation, due to the special form for the issue, can be used to qualitatively deduce the dominance. Comparisons suggest that the results obtained from the linear fitting are consistent with those qualitatively reached from the nonlinear physical relation. The consistency is true, no matter what the relation is between the two influencing factors. Corresponding to the negative relation between the density and temperature, there are two patterns. One is that the pressure increases with density but decreases with temperature. In this case, density dominates the variation of pressure. The second is that the pressure increases with temperature but decreases with density, and thus temperature dominates the variation of pressure. The third pattern is for the positive relation between density and temperature. In this case, density and temperature both have positive contributions to the variation of pressure, and which of them is more important can further be assessed with the linear fitting method. [ABSTRACT FROM AUTHOR]

Fluorescence emission and excitation spectra of para-phenylene vinylenes n PV with n = 1 -4 styryl units are investigated experimentally and theoretically as a function of the temperature and the polarizability of the solvent. At low temperatures, the vibronic structures of the So↔S[sub 1] emission and excitation bands are mirror symmetrical with negligible 0-0 energy gaps. The frequencies of the prominent vibrational modes are assigned to the second longitudinal acoustic phonon modes of the entire molecules and to localized carbon—carbon stretching vibrations. The complete vibronic structures of the spectra are calculated at the ab initio Hartree-Fock (HF/6-311G[sup *]) and restricted configuration interaction singles (RCIS/6-311G[sup *]) levels of theory assuming planar C[sub 2h] molecular symmetry. The theoretically predicted spectra are in good agreement with the experiments. At room temperature, a 0-0 energy gap between the first band maxima opens, and the mirror symmetry between absorption and emission is lost. The vibronic band shapes and 0-0 band gaps are successfully simulated with a combination of Gaussian and exponential broadening of the low temperature spectra. The exponential term reflects the differences in thermal population of the phenyl-vinyl torsional modes in the SO and S[sub 1] electronic states. Spectral shifts upon changes in temperature and solvents are quantitatively explained by changes in the refractive index of the environment. From extrapolation of the experimental data the vertical and adiabatic transition energies of the oligomers in vacuo are obtained and compared to RCIS and semi-empirical quantum chemical calculations, respectively. [ABSTRACT FROM AUTHOR]