Suchergebnisse

Abstract
Background
The ecotoxicological risk posed by metals and their mixtures in sediments depends on their bioavailability. Many methods for evaluating the bioavailability of metals in sediments/soils are time-consuming and expensive, and frequently result in equivocal outcomes. The diffusive gradients in thin films (DGT) technique is a good measure of bioavailability for metals that can avoid the above drawbacks. Therefore, more effective approaches to this method should be developed that focus on metal bioavailability. No studies have been conducted using DGT to assess metal mixtures to aquatic biota in sediments. This study is therefore the first attempt to assess sediment toxicity of metals and their mixtures to aquatic biota based on the DGT technique. The intertidal zone of the Pearl River Estuary is selected as a case study.

Results
The bioavailable (DGT-labile) concentrations of metals range as follows (μg/L): Cd, 0.34–3.62; Pb, 1.35–1.92; Ni, 0.67–92.83; Cu, 0.74–10.30; Zn, 28.60–296.94; Co, 0.03–58.85; Fe, 7.23–4539.36; and Mn, 19.40–6626.83. The risk quotient (RQ), which is the ratio between the measured metal concentrations in the environment (MEC) and the predicted no-effect concentration (PNEC), is conducted to evaluate the single metal risk. The RQ based on summing up the MEC/PNEC ratios (RQMEC/PNEC) and the RQ based on sum of toxic units (RQSTU) are used to assess risk of metal mixture. TheRQ values of Cd, Pb, Ni, Cu, Zn, Fe, and Mn significantly exceed 1, indicating that the adverse effects of the metals are not negligible. Regarding the toxicity of metal mixtures, the values of RQMEC/PNEC and RQSTU are both between 62.45 and 743.48, revealing that the possible risk has already occurred in the study area.

Conclusions
The two methods of RQMEC/PNEC and RQSTU based on DGT-labile metal concentrations are effective and suitable to estimate the toxicity of metal mixtures in sediments.

The Gulf region's primary economic relationships are rapidly shifting from West to East. Relations with China, Japan and South Korea are becoming increasingly strategic in nature: based on a degree of mutual dependence far greater than is present in Gulf-Western relations. The balance of global politics will be critically affected by this powerful emerging relationship. This book provides documentation of the trend and examines some of the political and strategic issues which follow from it

The article is devoted to the consideration of issues related to women's participation in the Olympic Games in history and modern world. Special attention is paid to the analysis of sociological researches aimed at the identification of problematic aspects of women's sports at the Olympic Games. The authors analyze the tendencies of the influence of feminist movement on the development of the women's participation in the Olympic movement and sports equality, the development of traditionally female and "non-female" sports. It is shown that the development of feminism rhetoric in sports has negative consequences for the social status of female athletes and changes the ideas on the sports ideals.

Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily transmitted from person to person through respiratory droplets and aerosols. It is also possible for the virus to be transmitted indirectly through environmental contamination. The likelihood of environmental transmission depends on several factors, including the survival time of the virus in respiratory secretions. However, the stability of SARS-CoV-2 in respiratory secretions has not been investigated. In this study, we compared the half-life of the SARS-CoV-2 antigen in respiratory secretion under different conditions. We applied respiratory secretion (5 µL) to glass slides, air-dried the slides for 1 h, and kept them at 24 °C or 4 °C for 10 days. Respiratory secretions were also placed in test tubes (sealed to preserve moisture) and in normal saline for 10 days. The concentration of SARS-CoV-2 antigen in all samples was simultaneously measured using colloidal gold immunochromatography, and the half-life of the antigen was calculated. The half-life of the antigen in the wet (sealed tube) and saline samples at room temperature was 5.0 and 2.92 days, respectively. The half-life of the antigen in the air-dried sample at room temperature and at 4 °C was 2.93 and 11.4 days, respectively. The half-life was longer in respiratory secretions than that in normal saline. The half-life was also longer in respiratory secretions, at a lower temperature, and under wet conditions. Therefore, environmental transmission can also play a significant role in the spread of the virus. Robust prevention and control strategies could be developed based on the half-life of the antigen in respiratory secretions.

Background: The nature of the Canadian population 65+ has changed considerably over the past several decades. They comprise a larger proportion of the population, are better educated, and are wealthier than previous generations. We estimate the contributions of chronological aging, temporal periods, and birth cohort effects on the trends in the major depressive episode (MDE) prevalence among Canadian seniors from 1994/1995 to 2017/2018. Methods: Using data from two sets of national health surveys, the National Population Health Survey (NPHS) and the Canadian Community Health Survey (CCHS). Pooled data on 150,246 survey respondents aged 65+ from 16 repeated cross-sectional surveys are included. Hierarchical regression age-period-cohort models were used to visualize the linear and non-linear effects of age, period, and cohort trends in late-life depression. Results: We found that: the prevalence of MDE in later life fluctuated non-significantly during the study time period; the probability of developing MDE declined with increasing age from 65 to 80+ (β = −.32, p = .027). The significant quadratic birth cohort predictor showed a non-linear increasing association with the prevalence of MDE from the earlier to later-born cohorts (β = .01, p = .049). We also found that females 65+ were consistently more likely to be depressed than males 65+ (β = .47, p = .007). The significantly negative "age × female" interaction shows that age exerts a greater effect on females' probability of developing MDE than males (β = −.09, p = .011). There were no consistent significant period effects but there were peaks in prevalence around 2001, 2008, and 2012 which corresponded to some recent historical events. Our moderation analysis documents that lower levels of education significantly contributed to the higher rates of depression among cohorts born earlier in the 20th century. Conclusions: Our findings show the presence of strong chronological age and cohort effects and weaker period effects on the prevalence of late-life depression in Canadian seniors.

Using the case of a state-owned coal mining enterprise located in an agriculture-dominated region of China undergoing rapid industrialisation, this empirical study investigates how employees express their opinions during neoliberal restructuring. The findings show that workers cautiously select their voice channels and strategies in the context of increasing levels of unequal income distribution and managerial power. This article highlights the legacy of socialist ideology and practice, the prevailing cultural values and norms, and the close interpersonal relationships which together shape the localities in which workers develop their voice and strategies for action. (China/GIGA)