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Background: Self-disclosure may enhance positive illness perceptions, whereas patients with systemic lupus erythematosus (SLE) always facing negative illness perceptions due to multiple reasons, so elucidation of factors affecting self-disclosure may facilitate the development of quality of life. Methods: A total of 161 hospitalized patients with SLE were recruited. Scales on demographic and clinical characteristics, self-disclosure, psychosocial status (e.g. Social Support Rating Scale – SSRS) and quality of life were used to collect related information from clients. Univariate analysis was performed by Kruskal–Wallis rank-sum test or chi-square test, and multivariate analysis by ordinal logistic regression. Results: Social support, drinking, depression and cause of hospitalization were found to be influencing factors of self-disclosure. Multiple logistic regression analyses revealed that the significant and independent factors associated with self-disclosure in patients with SLE were social support, drinking and depression. Domains of LupusQoL, except physical health and fatigue, were positively correlated with self-disclosure. Conclusions: With the increase of social support, the level of self-disclosure become worse, drinking, depression and cause of hospitalization are risk factors for it. Moreover, the level of self-disclosure is positively related to the LupusQoL. Medical staff should formulate effective measures according to the results to improve self-disclosure in patients with SLE and promote their quality of life. [ABSTRACT FROM AUTHOR]

Aim: Climate change is expected to have important effects on plant phenology and carbon storage, with further shifts predicted in the future. Therefore, we proposed the community carbon accumulation rate (CAR) from the start of the growing season (SOS) to the peak of the growing season (POS) to fill the gap that the dynamic interactions between plant phenology and plant carbon research. Location: Tibetan Plateau. Major taxa: Alpine grassland plants. Time period: 2015. Methods: We conducted a transect survey across grasslands to measure community aboveground net primary production and carbon concentration. Additionally, phenology indicator data (SOS and POS) were extracted from the Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index version 3 database. Next, we used 'changepoint' analysis to detect the patterns of CARs, and performed linear regression and one‐way ANOVA to explore the variability of CARs in response to the environmental factors. Ultimately, the total effects of environmental factors on CARs were illustrated by a structural equation model. Results: Our results indicated that three CAR patterns were detected, which are low‐CAR (0.15 g/m2/day), medium‐CAR (0.31 g/m2/day) and high‐CAR (0.84 g/m2/day) patterns. We found that the availabilities of water and heat mediated CARs by regulating soil nutrition variability, and that drought climate and insufficient soil resources co‐constrained the community CAR at long time‐scales. In contrast, high CAR could be explained by more water and heat availability via either direct or indirect effects on soil moisture and soil nutrients. Main conclusions: Our findings highlight that water and heat availability are critical driving factors in ecological carbon accumulation processes undergoing climate change. Meanwhile, the vegetative phenology also has important effect on carbon accumulation. Consequently, we propose incorporating the dynamic interactions between plant phenology and plant carbon into the ecological carbon cycle model to improve our understanding of resource utilization and survival strategies of plants under environmental change. [ABSTRACT FROM AUTHOR]

Fertilization is an effective management measure for recovery of degraded grasslands. To better understand the effects of fertilization on community structure and productivity of lightly and severely degraded alpine meadows, we conducted a fertilization experiment in northern Tibet since 2008. The treatments were addition of nitrogen (N) alone (50 kg N · hm-2 a-1, LN; 100 kg N · hm-2 · a-1, HN) or addition of both phosphorus (P) and N (50 kg N · hm-2 · a-1 +50 kg P · hm-2 · a-1, LN+P; 100 kg N · hm-2 · a-1 +50 kg P · hm-2 . a-1, HN+P) in each of the two types of degraded alpine meadows. N addition alone significantly affected plant community coverage or productivity in neither the slightly nor the severely degraded alpine meadow, while addition of both N and P significantly increased plant community coverage, aboveground and below-ground biomass of the alpine meadows. This suggested that productivity of this alpine meadow is colimited by N and P · HN and HN+P significantly decreased species richness and evenness in the lightly degraded grassland, indicating that HN was not beneficial for the lightly degraded grassland to maintain species diversity and community stability. N addition significantly reduced the root to shoot ratio in the severely degraded meadow. In the lightly degraded meadow, N addition alone, especially with a high amount (HN), enhanced the importance values (IV) and biomass of grasses, while fertilization with both N and P increased those of sedges. In the severely degraded meadow, fertilization had little effect on IV of grasses or sedges, but improved biomass of forbs. The results suggested that LN+P could be employed in recovery of lightly degraded alpine meadows, but other management measures such as fencing and reseeding may be needed for recovery of severely degraded alpine meadows. [ABSTRACT FROM AUTHOR]

In order to solve the problems of the efficiency and safety of the control stage in a steam turbine. Based on RANS with the application of structural hexahedron mesh and finite volume method, the flow field of the control stage in a steam turbine was calculated. Pressure contour and velocity contour were performed to analysis the flow field of the control stage under different conditions. Torque of the blade rotating one circle were performed. Amplitude-frequency map of the torque was obtained according to the FFT analysis. The results indicate that the flow field is nonuniform under partial admission condition. The maximum torque of the blade is 2.2 times larger than that in the flow area under four valves open condition, while under three valves open condition the maximum torque of the blade in the blocked area is 1.8 times larger. It can help to check the safety of the blade. Spectrum analysis indicates that the typical low frequency of the exciting force is caused by the rotating speed of the blade. The efficiency of the control stage under three valves open condition is 7% lower than that under four valves open. [ABSTRACT FROM AUTHOR]

Seasonal freeze-thaw cycle and its change pattern under the scenarios of climate warming might exert strong effects on the soil nitrogen mineralization in alpine forests. In this paper, intact soil cores were collected from the subalpine/ alpine forests along an altitudinal gradient in west Sichuan, and an incubation test was conducted to study the soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen in the forests during growth season and seasonal freeze-thaw period under simulated scenarios of global warming. In the test soils, the NH4 +-N and NO3 --N contents both showed a clear tendency of decreased in the period from growth season to the onset stage of freezing, increased at deep freezing stage, and decreased again at the early stage of thawing. The soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen were significantly lower in freeze-thaw period than in growth season, and the soil inorganic nitrogen was obviously immobilized. The soil nitrogen immobilization was stronger at middle altitudes but weaker at high altitudes, as compared with that at low altitudes, possibly due to the variation of soil temperature and its induced different freeze-thaw cycle. During growth period, the soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen showed an obvious increasing trend with the decrease of altitude, and the soil nitrogen mineralization was the strongest at low altitudes, implying that under the scenarios of climate warming, the increase of soil temperature promoted the soil nitrogen mineralization during growth season, and affected the soil nitrogen mineralization rate by increasing the frequency of freeze-thaw cycle and shortening the time period of freeze-thaw. Soil micro-environment could also affect the soil nitrogen mineralization in alpine forest regions. [ABSTRACT FROM AUTHOR]

Abstract: Seasonal variation of soil CO2 efflux is highly dependent on climate and plant phenology. On the Tibetan Plateau with an average altitude about 4000m a.s.l., variations of CO2 efflux may be strongly associated with the unique ecophysiology and climate over there. Our objectives were to quantify diurnal and seasonal variations of soil CO2 efflux, and to investigate the effects of daily and seasonal variations of soil temperature and phenology on soil CO2 efflux. CO2 efflux was measured in Lhasa River valley on the Tibetan Plateau using a static closed chamber technique and gas chromatography for 2 full years from September 1999 to August 2001. Soil CO2 effluxes showed similar diurnal change patterns and fluctuated from minimum at 5:00h to maximum at 11:00–14:00h in different phenological stages. Soil CO2 efflux exhibited pronounced variation corresponding to crop phenology and soil temperature, with a minimum value of 0.4gCO2 m−2 d−1 in January and a maximum value of 15.0gCO2 m−2 d−1 in mid June. The observed mean soil CO2 effluxes were 6.6g CO2 m−2 d−1 in the growing season and 2.8gCO2 m−2 d−1 in the non-growing season, with an average of 6.0gCO2 m−2 d−1 in the 2 full measured years. While soil CO2 efflux was strongly dependent on soil temperature with highest correlation found with 5cm depth temperature, maximum values of CO2 efflux coincided with maximum values of leaf area index (LAI) and live root biomass (LRB) in mid June but not with maximum soil temperature in July. CO2 efflux was positively correlated with LAI and LRB in the growing season from March to August. Soil moisture had relatively little effect on soil CO2 efflux due to frequent irrigation. Simulation of soil CO2 efflux with soil temperature in the whole 2 years of observation led to overestimates in non-growing season and underestimates in the growing season. Taking account of the influence of crop phenology, a temperature dependent exponential model was separately used to fit CO2 efflux in growing season and non-growing season. This alteration increased 7.5% of explained variance of seasonal variability and provided more accurate prediction of soil CO2 efflux. Q 10 values ranged 2.0 in growing season and 2.5 in non-growing season. Total annual loss of C from soil respiration was estimated to be 579±13gCm−2 per year at the site. The results suggest that soil temperature is the determinant factor controlling temporal variation of soil CO2 efflux and crop phenology modifies the temperature dependence of soil CO2 efflux in different growing periods. Our results also indicate that root respiration in the growing season can be estimated approximately by using the discrepancy between CO2 efflux relations in the growing season and non-growing season of cropland ecosystem. [Copyright &y& Elsevier]

Total amount, distribution pattern and occurrence time of precipitation determine the water condition of alpine vegetation growth on the Tibetan Plateau, China. Precipitation use efficiency (the ratio of aboveground productivity to precipitation, PUE) is an effective indicator for the relationship between precipitation and vegetation productivity. In this study, we calculated aboveground net primary productivity (ANPP) of an alpine steppe-meadow in northern Tibetan Plateau from 2000 to 2016 based on the correlation model between long-term monitoring biomass data and enhanced vegetation index (EVI) in Damxung. Meteorological data during the same period was also analyzed. Growing season precipitation (GSP) represented the amount of precipitation, improved precipitation concentrated index (PCI) indicated their distribution pattern in the growing season, and precipitation centroid (PC) represented the time of precipitation occurrence. Structural equation model was used to explore the effects of climatic factors on PUE and ANPP, with the consideration of growing season temperature (GST). Results showed that ANPP of this alpine steppe-meadow was mainly controlled by precipitation during the growing season. GSP and ANPP showed significantly positive correlation, whereas the correlation of GST with PUE and ANPP was not significant. PCI and PUE showed significantly positive correlation, which indicated that concentrated distribution of precipitation was beneficial to the increase of PUE. Indirect coefficient between PCI and ANPP was greater than direct coefficient, indicating that PCI influenced ANPP through PUE. Changes of precipitation concentrated time did not show significant effect on PUE and ANPP. Our results suggested that under the rapid climate warming on the Tibetan Plateau, future changes of precipitation and their concentration would have important impacts on aboveground productivity of the alpine grassland.

A long-term experiment, involving exogenous N addition and simulated warming, was conducted in an alpine meadow in Damxung, northern Tibet, to study how warming and N addition influence community production and biomass allocation. The results showed that warming resulted in a warm but dry microsite, that was, air temperature increased by 1.6 ℃ and soil surface temperature increased by 1.4 ℃, and soil water content decreased by 4.7%. Under no N addition treatments, warming significantly decreased plant aboveground biomass by 61.5%, 108.8% and 77.1% in 2012, 2013 and 2014, respectively. Under high N treatments (40 and 80 kg N·hm -2 ·a -1 ), warming had no significant effect on aboveground biomass. These findings indicated that the effect of warming might be dependent on N addition level, and N addition could compensate for soil N loss caused by warming. Warming led to an increase in root/shoot by 98.6%, 60.7% and 97.8% in 2012, 2013 and 2014 under no N addition treatments, respectively. Under the ambient condition, the change percentages of aboveground and belowground biomass of plant communities first increased and then decreased along an N gradient, with the saturation thresholds of above- and below-ground biomass for N addition 56.0 and 55.5 kg N·hm -2 ·a -1 , respectively. Under the warming condition, above- and belowground biomass increased linearly with increasing N addition. These findings suggested that warming modulated the response patterns of alpine meadows to exogenous N input, which was mainly caused by decreased soil inorganic N under warming. The estimation of N thresholds highlights that alpine meadows are more sensitive to future N deposition than other types of grasslands.

Precipitation change is an important factor in the inter-annual variation of grassland growth on the Tibetan Plateau. The total amount, distribution pattern and concentration time are three basic characteristics of precipitation change. The temporal and spatial characteristics of precipitation change were analyzed based on climate data of 145 meteorological stations on the Tibetan Plateau and nearby areas from 2000 to 2015. The total precipitation amount was characterized by annual precipitation, distribution pattern of precipitation during the year was characterized by improved precipitation concentration index (PCI), and precipitation centroid (PC) was defined to indicate the change in precipitation concentrated time. To better illustrate the response of grassland to precipitation change, vegetation growth status was characterized by the maximum value of normalized difference vegetation index (NDVI max ). Results indicated that the annual precipitation and PCI had an apparent gradient across the whole plateau and the latest PC occurred in the southern plateau. NDVI max of alpine shrub grassland was significantly correlated with the change of PCI,increased with even distribution of precipitation during growth period, and limited by the total annual precipitation. Alpine meadow did not show significantly correlations with these three indices. The inter-annual variability of NDVI max of steppe was controlled by both PCI and PC. NDVI max of alpine desert grassland was mainly controlled by annual precipitation. In addition to annual total amount of precipitation, the distribution characteristics of precipitation should be further considered when the influence of precipitation change on different types of vegetation on the Qinghai Tibet Plateau was studied.

Global climate warming and increasing nitrogen (N) deposition, as controversial global environmental issues, may distinctly affect the functions and processes of terrestrial ecosystems. It has been reported that the Qinghai-Tibet Plateau has been experiencing significant warming in recent decades, especially in winter. Previous studies have mainly focused on the effects of warming all the year round; however, few studies have tested the effects of winter warming. To investigate the effects of winter warming and N addition on plant community structure and species composition of alpine meadow, long-term N addition and simulated warming experiment was conducted in alpine meadow from 2010 in Damxung, northern Tibet. The experiment consisted of three warming patterns: Year-round warming (YW), winter warming (WW) and control (NW), crossed respectively with five N gradients: 0, 10, 20, 40, 80 kg N·hm -2 ·a -1 . From 2012 to 2014, both warming and N addition significantly affected the total coverage of plant community. Specifically, YW significantly decreased the total coverage of plant community. Without N addition, WW remarkably reduced the vegetation coverage. However, with N addition, the total vegetation coverage gradually increased with the increase of N level. Warming and N addition had different effects on plants from different functional groups. Warming significantly reduced the plant coverage of grasses and sedges, while N addition significantly enhanced the plant coverage of grasses. Regression analyses showed that the total coverage of plant community was positively related to soil water content in vigorous growth stages, indicating that the decrease in soil water content resulted from warming during dry seasons might be the main reason for the decline of total community coverage. As soil moisture in semi-arid alpine meadow is mainly regulated by rainfalls, our results indicated that changes in spatial and temporal patterns of rainfalls under the future climate change scenarios would dramatically influence the vegetation coverage and species composition. Additionally, the effects of increasing atmospheric N deposition on vegetation community might also depend on the change of rainfall patterns.

Understanding the dynamics and underlying mechanism of carbon exchange between terrestrial ecosystems and the atmosphere is one of the key issues in global change research. In this study, we quantified the carbon fluxes in different terrestrial ecosystems in China, and analyzed their spatial variation and environmental drivers based on the long-term observation data of ChinaFLUX sites and the published data from other flux sites in China. The results indicate that gross ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem productivity (NEP) of terrestrial ecosystems in China showed a significantly latitudinal pattern, declining linearly with the increase of latitude. However, GEP, ER, and NEP did not present a clear longitudinal pattern. The carbon sink functional areas of terrestrial ecosystems in China were mainly located in the subtropical and temperate forests, coastal wetlands in eastern China, the temperate meadow steppe in the northeast China, and the alpine meadow in eastern edge of Qinghai-Tibetan Plateau. The forest ecosystems had stronger carbon sink than grassland ecosystems. The spatial patterns of GEP and ER in China were mainly determined by mean annual precipitation (MAP) and mean annual temperature (MAT), whereas the spatial variation in NEP was largely explained by MAT. The combined effects of MAT and MAP explained 79%, 62%, and 66% of the spatial variations in GEP, ER, and NEP, respectively. The GEP, ER, and NEP in different ecosystems in China exhibited 'positive coupling correlation' in their spatial patterns. Both ER and NEP were significantly correlated with GEP, with 68% of the per-unit GEP contributed to ER and 29% to NEP. MAT and MAP affected the spatial patterns of ER and NEP mainly by their direct effects on the spatial pattern of GEP., (© 2012 Blackwell Publishing Ltd.)