中国环境管理分区:方法与方案

我国生态环境可持续性及其影响因素的区域差异显著,各地区环境管理面临的主要挑战和需要优先解决的生态环境问题不同。进行环境管理分区,根据各地区生态环境特征及其影响因素的差异性,制定有针对性的环境管理政策,将有效促进我国区域生态环境的整体优化。采取定性和定量分析相结合的方法进行我国环境管理分区。首先,在我国3大自然区的基础上,根据我国的自然地理格局和已有的相关区划成果,把我国划分为4个环境管理大区,包括:南部季风区、北部季风区、西北干旱区和青藏高寒区。其次,通过建立的包含13个指标的环境管理分区指标体系,采用一维化欧式距离法分析各环境管理大区下相邻省级行政区环境特征的相似性,把环境特征相似性大的相邻地区划分到同一分区,得到以省级行政区为基本单元的我国环境管理分区方案。然后,结合地区间历史渊源和区域未来发展趋势分析,对基于相似性分析的初步分区方案进行调整,把我国划分为8个以省级行政区为基本单元环境管理区。最后,根据相关调整原则和方法,对以省级行政区为基本单元的分区方案的边界线进行调整,得到以地级行政区为基本单元的分区方案,把我国划分为东北地区、华北平原区、华北山地与高原区、东南沿海地区、长江流域中游地区、西南地区、西北干旱区和青藏高寒区8个环境管理区。     

Impact of social support intensity on walking in the severely obese: a randomized clinical trial

Objective: There are few established methods for promoting physical activity (PA) in the severely obese. Because social support is a potential method for promoting PA, we compared mean steps/day during 18 weeks in severely obese outpatients receiving either standard support (SS) or added support (AS). Methods and Procedures: Eighty severely obese outpatients from an obesity clinic were invited; 66 provided written consent, 55 were randomized, and 42 were included in final analyses (9 men, 33 women; age 44.4 ± 13.1 years; BMI 41.9 ± 5.5 kg/m²). All participants received a pedometer and a walking promotion booklet. In addition to SS, the AS group received ten 2‐h group counseling sessions aimed at increasing weekly accumulated steps, every second week during the study. Each participant was asked to complete a 7‐day walking diary every second week (10 observations). Results: Baseline steps/day was 6,912 for the AS group and 5,311 for the SS group (P = 0.023). Data at 18 weeks showed that the AS group recorded 10,136 steps/day and the SS group 6,118 steps/day (P = 0.024). There was no allocation × time interaction (P = 0.46). During the follow‐up period as a whole, the AS group recorded 1,794 more steps/day than the SS group (P = 0.0074). Discussion: The AS group recorded more steps/day than the SS group, reaching a mean level of ～10,000 steps/day. However, the nonsignificant interaction between allocation × time suggests that this difference was present already at baseline and did not increase during follow‐up.     

Assessment of physical activity in youth

Despite much progress with physical activity assessment, the limitations concerning the accurate measurement of physical activity are often amplified in young people due to the cognitive, physiological, and biomechanical changes that occur during natural growth as well as a more intermittent pattern of habitual physical activity in youth compared with adults. This mini-review describes and compares methods to assess habitual physical activity in youth and discusses main issues regarding the use and interpretation of data collected with these techniques. Self-report instruments and movement sensing are currently the most frequently used methods for the assessment of physical activity in epidemiological research; others include heart rate monitoring and multisensor systems. Habitual energy expenditure can be estimated from these input measures with varying degree of uncertainty. Nonlinear modeling techniques, using accelerometry perhaps in combination with physiological parameters like heart rate or temperature, have the greatest potential for increasing the prediction accuracy of habitual physical activity energy expenditure. Although multisensor systems may be more accurate, this must be balanced against feasibility, a balance that shifts with technological and scientific advances and should be considered at the beginning of every new study.     

Method for Spiking Soil Samples with Organic Compounds

We examined the harmful side effects on indigenous soil microorganisms of two organic solvents, acetone and dichloromethane, that are normally used for spiking of soil with polycyclic aromatic hydrocarbons for experimental purposes. The solvents were applied in two contamination protocols to either the whole soil sample or 25% of the soil volume, which was subsequently mixed with 75% untreated soil. For dichloromethane, we included a third protocol, which involved application to 80% of the soil volume with or without phenanthrene and introduction of Pseudomonas fluorescens VKI171 SJ132 genetically tagged with luxAB::Tn5. For both solvents, application to the whole sample resulted in severe side effects on both indigenous protozoa and bacteria. Application of dichloromethane to the whole soil volume immediately reduced the number of protozoa to below the detection limit. In one of the soils, the protozoan population was able to recover to the initial level within 2 weeks, in terms of numbers of protozoa; protozoan diversity, however, remained low. In soil spiked with dichloromethane with or without phenanthrene, the introduced P. fluorescens VKI171 SJ132 was able to grow to a density 1,000-fold higher than in control soil, probably due mainly to release of predation from indigenous protozoa. In order to minimize solvent effects on indigenous soil microorganisms when spiking native soil samples with compounds having a low water solubility, we propose a common protocol in which the contaminant dissolved in acetone is added to 25% of the soil sample, followed by evaporation of the solvent and mixing with the remaining 75% of the soil sample.     

Autumn phytoplankton assemblages in temperate lakes of different eutrophication level in the middle part of Sweden

Phytoplankton assemblages were studied during autumn 1998 in oligo-, meso- and eutrophic lakes in central Sweden (62°54'N). Differences in phytoplankton assemblages have been detected both in space and time. In eutrophic lakes coccoid Chlorophyceae dominated quantitatively during September and October. Diatoms were the most diverse group in all types of lakes in September and in meso- and oligotrophic lakes in October. In November Cryptophyceae became the most abundant group in all lakes. The total richness of species decreased in the meso- and oligotrophic environments in November compared to September and October, whilst in the eutrophic environment it remained almost unchanged. Cluster analyses, using both presence-absence and presence-absence in combination with abundance matrices, showed similar results and a good resolution between the lakes of different eutrophication conditions. We conclude that the phytoplankton assemblages of the lakes studied depended on the trophic conditions and thus they can be used for resolution between different eutrophication levels.     

Influence of chlorophyll concentrations on the reliability of measurements with an oxygen electrode when studying photosynthetic efficiency in bioassays using microalgae

Euglena gracilis and Chlamydomonas reinhardtii were used as model organisms to establish the best conditions for studying photosynthetic efficiency using the Light Pipette – experimental system, which enables sensitive detection of changes in oxygen evolution/consumption and an easy collection and digitalisation of data. Chlorophyll concentrations of 0.005, 0.025, 0.050 and 0.075 mgmL^-1 were investigated using different light regimes. Cultures of E. gracilis at the same chlorophyll concentration absorbed more light(measured at 580 μmol m^-2 s^-1) than those of C. reinhardtii. Cell density had a considerable effect on the reliability of measurements. Chlorophyll concentrations between 0.025 mg_Chl ml^-1 and 0.050 mg_Chlml^-1 can be recommended when applying the Light Pipette system in bioassays using microalgae. This revised version was published online in August 2006 with corrections to the Cover Date.     

Novel ways to prevent proteolysis — prophytepsin and proplasmepsin II

The recently determined crystal structures of two aspartic proteinase zymogens, prophytepsin from barley and proplasmepsin II from the malarial parasite Plasmodium falciparum, have provided new insights into zymogen inactivation. Prophytepsin shows a variation of the mechanism of inhibition used by the well-known gastric aspartic proteinase zymogens, whereas proplasmepsin II uses a completely new mode of inactivation.     

RAPID SCREENING FOR SALMONELLA IN FISHMEAL BY ENRICHMENT-IMMUNOASSAY

We previously described an enrichment-immunoassay utilizing a T6 monoclonal antibody capture enzyme-linked immunosorbent assay. Here we evaluated it for the rapid screening for Salmonella in fishmeal obtained from the national Animal and Plant Quarantine service in the People's Republic of China. In this method, the number of Salmonella present is first expanded by appropriate enrichment cultures, and the pathogens are then directly detected by the T6 immunoassay. In a total of 94 enrichment cultures of fishmeal, we obtained an overall concordance of 98% between the results obtained in parallel by this method and by conventional test method. The positive prediction by this method was 92% and the negative prediction was 100%. The turn around time for the new test was 27 h which is a significant improvement from the turn around time exceeding 96 h required for the conventional test method. This test proved to be compatible with the routine work flow in the practical setting of a quarantine laboratory.