Abstract Global changes arouse large-scale fragmentation of forests, which has a profound impact on the balance of the global carbon cycle. However, the effect and process of temperate forest fragmentation on photosynthetic carbon uptake are not clear. We used remote sensing datasets to describe the degree of forest fragmentation and clarify the relationship between fragmentation and photosynthetic carbon uptake in the temperate forests of northeastern China. The results show that forest fragmentation has high spatial heterogeneity and promotes photosynthetic carbon uptake by 14% in the cold temperate zone and 10% in the middle temperate zone. Hydrothermal conditions are the dominant influencing path, explaining 60% of the variation in the cold temperate zone and 49% of the variation in the middle temperate zone. In addition, temperature is the dominant driver of the cold temperate zone, and water is the dominant driver of the middle temperate zone. Our research calls for a deeper understanding of the carbon cycle of fragmented temperate forests, and it is necessary to consider appropriate human intervention in forest management.
In the present paper wheat flag leaves were collected during the tasseling period, and then 1 mmol x L(-1) hydrogen peroxide was added to induce oxidative stress on leaves. In comparison, the detached leaves were also kept under drought or darkness condition for 24 h for the same purpose. Following the preparation of chloroplasts, polarization fluorescence spectroscopic method was utilized to measure fluorescence emission spectra and fluorescence excitation spectra of chloroplasts in the case of VV, VH, HV and HH, where V and H is representative of vertical polarization and horizontal polarization, respectively. Gaussian deconvolution was done on emission spectra, and the fitting data revealed that no matter whether Chla or Chlb molecules were excited upon excitation at 436 nm or 475 nm, the ratio of fluorescence peak area at 684 nm and 720 nm, i. e. A684/ A720, tends to increase slightly after oxidative stress. In addition, some useful information was available from polarization excitation spectra, where it was observed that the treatment of oxidative stress gave rise to higher ratio of excitation peak intensity between 436 nm and 475 nm (E436/E475), indicating that Chla made more contribution to PSII fluorescence emission than Chlb did. Simultaneously, the ratio of 475 nm and 600 nm (E475/E600), representing the energy transfer efficiency from Car to Chlb, was also found to be higher after the detached leaves were treated. In addition, both fluorescence polarization and viscosity were calculated in this paper, and the data showed that oxidative stress should be responsible for higher fluorescence polarization at 680 nm and higher viscosity in microenviroment. The above-mentioned phenomenon is consistent with the lipid peroxidation of unsaturated fatty acids. It also provides a simple and feasible method to study oxidative stress.
Abstract A comprehensive quantification of global forest fragmentation is urgently required to guide forest protection, restoration and reforestation policies. Previous efforts focused on the static distribution patterns of forest remnants, potentially neglecting dynamic changes in forest landscapes. Here, we map global distribution of forest fragments and their temporal changes between 2000 and 2020. We find that forest landscapes in the tropics were relatively intact, yet these areas experienced the most severe fragmentation over the past two decades. In contrast, 75.1% of the world’s forests experienced a decrease in fragmentation, and forest fragmentation in most fragmented temperate and subtropical regions, mainly in northern Eurasia and South China, declined between 2000 and 2020. We also identify eight modes of fragmentation that indicate different recovery or degradation states. Our findings underscore the need to curb deforestation and increase connectivity among forest fragments, especially in tropical areas.
Digital trade includes cross-border e-commerce focus on goods trade and digital service trade focus on service trade. Digital service trade refers to the service trade that can be delivered digitally or has the potential of digital delivery, including insurance services, financial services, intellectual property services, telecommunications, computer and information services, other business services and cultural and entertainment services (UNCTAD,2020), this study mainly examine the contribution of 28 manufacturing industries in China to the competitiveness of digital services trade in these six categories. Data are drawn from Ministry of Commerce, State Administration of Foreign Exchange, International Trade Center (ITC),China Statistical Yearbook, ILO Statistics, China Input-Output Table.
Abstract Objective Light exposure is considered to be associated with reduced blood pressure (BP). However, longitudinal epidemiological studies concerning the light‒BP association with large samples are still limited. Methods This cohort study enrolled over 300,000 participants from the UK Biobank. Information on time spent in outdoor light during typical summer or winter days was obtained through questionnaires. Cases of hypertension and hypotension were identified using the 10th edition of International Classification of Diseases codes. Cox proportional hazard regression models were employed to estimate the light‒BP associations, restricted cubic splines were utilized to detect potential nonlinear associations, subgroup analyses were conducted to identify effect modifiers, and causal mediation analyses were performed to explore potential mechanisms. Results Using summer light exposure as an illustration, after a median follow-up of 13.4 years, each additional hour of summer light exposure was associated with an increased risk of hypertension (hazard ratio [HR] 1.011, 95% confidence interval [CI] 1.006‒1.017, P -nonlinear=0.803) and a decreased risk of hypotension (0.988, 0.977‒ 0.998, P -nonlinear=0.109). The light‒BP association is stronger in females ( P =0.022), those with short sleep duration ( P =0.049), and those with high genetic risk of hypertension ( P <0.001). Potential mechanisms included increasing biological age (proportion mediated, 24.1%, P <0.001), neutrophil count (5.4%, P <0.001), BMI (32.0%, P <0.001), etc. Conclusions Contrary to previous findings, our study revealed a positive association between light exposure and BP. Potential mechanisms include inflammation, aging, and behavioral lifestyle changes. Further epidemiological and experimental investigations are warranted to validate these novel findings.
Digital trade includes cross-border e-commerce focus on goods trade and digital service trade focus on service trade. Digital service trade refers to the service trade that can be delivered digitally or has the potential of digital delivery, including insurance services, financial services, intellectual property services, telecommunications, computer and information services, other business services and cultural and entertainment services (UNCTAD,2020), this study mainly examine the contribution of 28 manufacturing industries in China to the competitiveness of digital services trade in these six categories. Data are drawn from Ministry of Commerce, State Administration of Foreign Exchange, International Trade Center (ITC),China Statistical Yearbook, ILO Statistics, China Input-Output Table.
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