Characteristics and source apportionment of PM2.5 under the dual influence of the Spring Festival and the COVID-19 pandemic in Yuncheng city

Based on the online and membrane sampling data of Yuncheng from January 1st to February 12th, 2020, the formation mechanism of haze under the dual influence of Spring Festival and COVID-19 (Corona Virus Disease) was analyzed. Atmospheric capacity, chemical composition, secondary transformation, source apportionment, backward trajectory, pollution space and enterprise distribution were studied. Low wind speed, high humidity and small atmospheric capacity inhibited the diffusion of air pollutants. Four severe pollution processes occurred during the period, and the pollution degree was the highest around the Spring Festival. In light, medium and heavy pollution periods, the proportion of SNA (SO₄²⁻, NO₃⁻ and NH₄⁺) was 59.6%, 56.0% and 54.9%, respectively, which was the largest components of PM_2.5; the [NO₃⁻]/[SO₄²⁻] ratio was 2.1, 1.5 and 1.7, respectively, indicating that coal source had a great influence; the changes of NOR (nitrogen oxidation ratio, 0.44, 0.45, 0.61) and SOR (sulphur oxidation ratio, 0.40, 0.49, 0.65) indicated the accumulation of secondary aerosols with increasing pollution. The coal combustion, motor vehicle, secondary inorganic sources and industrial sources contributed 36.8%, 26.59%, 11.84% and 8.02% to PM_2.5 masses, respectively. Backward trajectory showed that the influence from the east was greater during the Spring Festival, and the pollutants from the eastern air mass were higher, which would aggravate the pollution. Meteorological and Spring Festival had a great impact on heavy pollution weather. Although some work could not operate due to the impact of the COVID-19 epidemic, the emission of pollutants did not reduce much.     

A conceptual framework: Redefining forest soil's critical acid loads under a changing climate

Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period. While the ecosystem was not in exceedance of the CAL, long-term nitrogen deposition pre-disposed the forest to other ecological stress. In combination, insects, drought, and nitrogen ultimately combined to cause the observed forest mortality. If any one of these factors were not present, the trees would likely not have died. This paper presents a conceptual framework of the ecosystem consequences of these interactions as well as limited plot level data to support this concept. Future assessments of the use of CAL studies need to account for multiple stress impacts to better understand ecosystem response.     

Social network theory in the behavioural sciences: potential applications

Social network theory has made major contributions to our understanding of human social organisation but has found relatively little application in the field of animal behaviour. In this review, we identify several broad research areas where the networks approach could greatly enhance our understanding of social patterns and processes in animals. The network theory provides a quantitative framework that can be used to characterise social structure both at the level of the individual and the population. These novel quantitative variables may provide a new tool in addressing key questions in behavioural ecology particularly in relation to the evolution of social organisation and the impact of social structure on evolutionary processes. For example, network measures could be used to compare social networks of different species or populations making full use of the comparative approach. However, the networks approach can in principle go beyond identifying structural patterns and also can help with the understanding of processes within animal populations such as disease transmission and information transfer. Finally, understanding the pattern of interactions in the network (i.e. who is connected to whom) can also shed some light on the evolution of behavioural strategies.     

Biological effects of selenium and relationships with carcinogenesis†

Selenium is an element that is both essential, at low levels of dietary intake, and toxic, at high levels, to man and a wide range of animals. The purpose of the communication is to review the evidence for the involvement of hyper‐ and hypo‐selenosis in the aetiology of cancer. High levels of selenium intake have been blamed for an increase in cancer, dental caries and an array of other conditions. Critical evaluation of the evidence, however, leads to the conclusion that such claims have little substance. On the other hand, low levels of selenium intake may be associated with an increased incidence of certain forms of cancer and there appears to be an inverse relationship between blood selenium levels and cancer death rate in the United States. Keshan Disease, in the People's Republic of China has only been shown to occur in populations severely depleted of selenium. In well nourished populations there is no evidence to indicate that selenium supplements have any prophylactic or therapeutic benefit against human diseases such as cancer, cardiovascular disease or cystic fibrosis.     

A stage-structured, Aedes albopictus population model

Aedes albopictus has been the fastest spreading invasive animal species in the world from the mid-1980s until the mid-2000s. In areas it infests, it disrupts native mosquito ecology and can potentially vector up to 21 viruses. To better understand the population dynamics of this species, we created a temperature dependent population model. A stage-structured model was chosen to allow each life-stage to have different temperature dependent mortality and development rates, and each stage was modeled with an ordinary differential equation. Model parameters and distributions were based upon literature values. Initially, a basic model was constructed. This model then had parameters that were forced based upon daily average temperatures. Several criteria were used to evaluate the model, including a comparison to field data from Lubbock, TX. In a stochastic version of the model, a 95% confidence limit contained 70.7% of the field data points. Based upon these results, we feel reasonably confident that we have captured the role of temperature in driving the population dynamics of Ae. albopictus.     

我国秦至清末的疫病灾害研究

本文根据《中国历代天灾人祸表》中疫病的文字记载，统计出各个历史时期疫病发生时间（季节）、频数及其与旱、涝（水）、地震、战争等灾难事件的关系，进而推测历史时期疫病所包含的急性传染病。统计发生周期，证实疫病周期与太阳、太阳系活动规律有明显的相关性。     

Analysis of the toxicogenomic effects of exposure to persistent organic pollutants (POPs) in Slovakian girls: correlations between gene expression and disease risk

The chemical composition of persistent organic pollutants (POPs) in the environment is not uniform throughout the world, and these contaminants contain many structurally different lipophilic compounds. In a well-defined study cohort in the Slovak Republic, the POP chemicals present in the peripheral blood of exposed children were chemically analyzed. The chemical analysis data revealed that the relative concentration and profile of structurally different organic pollutants, including polychlorinated biphenyls (PCBs), 2,2′-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p′-DDE), 2,2′-bis(4-chlorophenyl)-1,1,1-trichloro-ethane (p,p′-DDT), hexachlorobenzene (HCB) and β-hexachlorocyclohexane (β-HCH), may vary from individual to individual, even within the same exposure area. These chemicals can be broadly classified into two groups. The first group, the PCB congeners, primarily originated from industrial compounds and their byproducts. The second group of compounds originated from or was commonly used in the agricultural sector (e.g., DDT, HCB). The objective of this study was to examine the effects of the two POP exposure profiles on gene expression. For the study population, we selected pre-pubertal girls (mean age of 46.2 ± 1.4 months) with high POP concentrations in their blood (> 75% tile of total POP) and classified them in the high ‘PCB’ group when the total PCB concentration was significantly higher than the total concentration of other POP components and in the ‘Other Than PCB’ (OTP) group, when the total PCB concentration was significantly lower than the concentration of the other major POP constituents. A matched control group of girls (< 25% tile of total POP) was selected for comparison purpose (n = 5 per group). Our aims were to determine whether there were any common effects of high POP exposure at a toxicogenomic level and to investigate how exposure may affect physiological functions of the children in two different exposure scenarios. Global gene expression analysis using a microarray (Affymetrix Gene Chip Human genome U133 Plus 2.0 Array) platform was conducted on the total RNA of peripheral blood mononuclear cells from the girls. The results were analyzed by Partek GS, Louis, MI, which identified twelve genes (ATAD2B, BIVM, CD96, CXorf39, CYTH1 ETNK1, FAM13A, HIRA, INO80B, ODG1, RAD23B, and TSGA14) and two unidentified probe sets, as regulated differentially in both the PCB and OTP groups against the control group. The qRT-PCR method was used to validate the microarray results. The Ingenuity Pathway Analysis (IPA) software package identified the possible molecular impairments and disease risks associated with each gene set. Connective tissue disorders, genetic disorders, skeletal muscular disorders and neurological diseases were associated with the 12 common genes. The data therefore identified the potential molecular effects of POP exposure on a genomic level. This report underscores the importance of further study to validate the results in a random population and to evaluate the use of the identified genes as biomarkers for POP exposure.     

Heat illness among high school athletes--United States, 2005-2009

Introduction

Heat illness is a leading cause of death and disability among U.S. high school athletes.

Methods

To examine the incidence and characteristics of heat illness among high school athletes, CDC analyzed data from the National High School Sports-Related Injury Surveillance Study for the period 2005–2009.

Results

During 2005–2009, the 100 schools sampled reported a total of 118 heat illnesses among high school athletes resulting in ≥ 1 day of time lost from athletic activity, a rate of 1.6 per 100,000 athlete-exposures, and an average of 29.5 time-loss heat illnesses per school year. The average corresponds to a weighted average annual estimate of 9,237 illnesses nationwide. The highest rate of time-loss heat illness was among football players, 4.5 per 100,000 athlete-exposures, a rate 10 times higher than the average rate (0.4) for the eight other sports. Time-loss heat illnesses occurred most frequently during August (66.3%) and while practicing or playing football (70.7%). No deaths were reported.

Conclusions

Consistent with guidelines from the National Athletic Trainers’ Association, to reduce the risk for heat illness, high school athletic programs should implement heat-acclimatization guidelines (e.g., set limits on summer practice duration and intensity). All athletes, coaches, athletic trainers, and parents/guardians should be aware of the risk factors for heat illness, follow recommended strategies, and be prepared to respond quickly to symptoms of illness. Coaches also should continue to stress to their athletes the importance of maintaining proper hydration before, during, and after sports activities.

Impact of industry

By implementing preventive recommendations and quickly recognizing and responding to heat illness, coaches, athletic trainers, and the sporting community can prevent future deaths.     

Effects of veterinary fences on Wildlife conservation in Zimbabwe

In Zimbabwe, veterinary fences are used to control trypanosomiasis and foot- and-mouth disease, two important diseases that threaten cattle production and beef exports. Wildlife is implicated in both instances and the effects of fences on wildlife conservation and land use are discussed in relation to these two diseases. Advantages and disadvantages related to direct and indirect fence effects are outlined. Although the maintenance of fences for trypanosomiasis control is likely to become obsolete, control of foot- and-mouth disease will rely on fences for the foreseeable future. Most of Zimbabwe's protected wildlife areas are located in marginal agricultural land around the periphery of the country where cattle productivity is low. This land should be excluded from any involvement in the beef export industry rather than attempting its inclusion through cordoning and isolating individual protected areas. Within such land, the need for rigid veterinary restrictions should then disappear and allow more flexible strategies for disease control, including adaptive and imaginative approaches to land-use planning.     

论我国职业病诊断鉴定制度的缺陷及完善——兼评《职业病防治法修正案（草案）》的相关规定

我国现行职业病诊断鉴定法律制度存在较大缺陷,使得受害劳动者维权乏力,笔者在分析探讨职业病诊断鉴定制度所存相关问题的基础上,有针对性地提出改革完善的相应建议,同时对新出台的《职业病防治法修正案（草案）》的有关修订内容做出评议。