“无废城市”建设推进政策及措施的国别比较研究

“无废城市”建设已经成为应对城市固体废物（以下简称“固废”）管理挑战的国际趋势，我国也启动了“无废城市”建设试点工作。本文介绍了国际“无废城市”实践的背景和发展趋势，对我国和其他高收入国家的“无废城市”相关政策和具体实施方案进行了对比分析。分析结果表明，“无废城市”的推进政策与实施措施存在国别差异，我国的“无废城市”采纳了“问题导向”的推进策略，而高收入国家则是“目标导向”。最后对进一步推进我国“无废城市”建设试点工作提出了四点建议。     

ESTIMATING CENTRAL TENDENCY FROM UNCENSORED TRACE LEVEL MEASUREMENTS1

ABSTRACT: The statistical analysis of data which have trace level measurements has traditionally been a two-step process in which data are first censored using criteria based on measurement precision, and then analyzed with statistical methods for censored data. The process might be more informative if data were left uncensored. In this paper, information loss attributable to censoring and measurement noise are assessed by comparing the sample mean and median of uncensored measurements with a log regression mean and median based on censored data. Measurements are derived from lognormal parent distributions which have random variability characteristic of trace level measurement. The relative performance of estimators used with error-free samples and with samples having measurement noise can be explained by differences between the probability distributions of parents and measurements. Measurement introduces bias and dispersion and transforms lognormal parent distributions toward greater symmetry. Estimates using uncensored data are less biased and more accurate than the log regression mean and median when censoring exceeds about 50 percent, and are not much worse at any fraction censored. For data with many (80 percent) results below the limit of detection, bias may be quite severe.     

HLA-A,B,C,DR typing and 17-OHP determination for second trimester prenatal diagnosis of 21-hydroxylase deficient CAH

In 18 families at risk for the HLA-linked, 21-hydroxylase deficient form of autosomal recessive congenital adrenal hyperplasia (CAH), prenatal diagnosis (PD) was performed using two methods: (1) HLA-A,B,C typing and in the latter 11 cases also DR typing of cultured amniotic fluid cells (AFC) using the standard microcytotoxicity assay, and (2) measurement of second trimester amniotic fluid 17-hydroxyprogesterone (17-OHP) concentration using gel chromatography and radioimmunoassay. The accuracy of the prenatal predictions was confirmed by postnatal HLA typing of umbilical cord blood lymphocytes and by clinical evaluation. In 16/18 families, both HLA typing of AFC and 17-OHP measurements proved informative for PD. The predictions of both methods were concordant in 14/16 families (88 per cent). In ten of these families, a normal fetus was predicted, and in four, an affected fetus; all pregnancies were carried to term and all predictions were confirmed postnatally. In 2/16 cases (12 per cent), however, the predictions were discordant: the prenatal HLA typing indicated an affected fetus, whereas the 17-OHP values predicted a normal fetus. Both pregnancies were continued and two healthy boys were delivered. The discordance proved to be due to a ‘missed’ HLA antigen in one case and to serologically cross-reactive HLA antigens in the second. Finally, in 2/18 cases, prenatal assessment of fetal genotype had to rely on HLA typing alone as 17-OHP measurement was not performed in one family and in the second family the 17-OHP values obtained were not informative due to inadvertent continuation of hormone therapy to the date of amniocentesis. In both cases, the HLA typing data accurately predicted a normal fetus. In conclusion, a combination of HLA typing of cultured AFC and 17-OHP measurements of amniotic fluid permits accurate prenatal diagnosis of CAH in most cases (88 per cent). In addition, the supplementary use of HLA-DR typing of AFC as presented here for the first time proved helpful in families with HLA-A.B homozygosity due to parental sharing of antigens and can be informative for identifying HLA-B/21-OH recombinant haplotypes.     

Carbonyls in the metropolitan area of Mexico City: calculation of the total photolytic rate constants Kp(s(-1)) and photolytic lifetime (tau) of ambient formaldehyde and acetaldehyde

A great number of studies on the ambient levels of formaldehyde and other carbonyls in the urban rural and maritime atmospheres have been published because of their chemical and toxicological characteristics, and adverse health effects. Due to their toxicological effects, it was considered necessary to measure these compounds at different sites in the metropolitan area of Mexico City, and to calculate the total rate of photolytic constants and the photolytic lifetime of formaldehyde and acetaldehyde. Four sites were chosen. Sampling was carried out at different seasons and atmospheric conditions. The results indicated that formaldehyde was the most abundant carbonyl, followed by acetone and acetaldehyde. Data sets obtained from the 4 sites were chosen to calculate the total rate of photolysis and the photolytic lifetime for formaldehyde and acetaldehyde. Maximum photolytic rate values were obtained at the maximum actinic fluxes, as was to be expected.     

A Large-Eddy Simulation Study of the Convective Boundary Layer over Philadelphia during the 1999 Summer NE-OPS Campaign

This study presents a large-eddy simulation (LES) study of the convective boundary layer on August 1, 1999 over Philadelphia, PA during a summer ozone episode. The study is an evaluation of the Colorado State University's Regional Atmospheric Modeling System Version 4.3 (RAMS4.3) with the LES option using Northeast Oxidant and Particulate Study (NE-OPS) data. Simulations were performed with different imposed sensible heat fluxes at the ground surface. The model was initialized with the atmospheric sounding data collected at Philadelphia at 1230 UTC and model integrations continued till 2130 UTC. The resulting mean profiles of temperature and humidity obtained from the LES model were compared with atmospheric soundings, tethered balloon and aircraft data collected during the NE-OPS 1999 field campaign. Also the model-derived vertical profiles of virtual temperature were compared with NE-OPS Radio Acoustic Sounder System (RASS) data while the humidity profiles were compared with NE-OPS lidar data. The comparison of the radiosonde data with the LES model predictions suggests that the growth of the mixing layer is reasonably well simulated by the model. Overall, the agreement of temperature predictions of the LES model with the radiosonde observations is good. The model appears to underestimate humidity values for the case of higher imposed sensible heat flux. However, the humidity values in the mixing layer agree quite well with radiosonde observations for the case of lower imposed sensible heat flux. The model-predicted temperature and humidity profiles are in reasonable agreement with the tethered balloon data except for some small overestimation of temperature at lower layers and some underestimation of humidity values. However, the humidity profiles as simulated by the model agree quite well with the tethered balloon data for the case of lower imposed sensible heat flux. The model-predicted virtual temperature profile is also in better agreement with RASS data for the case of lower imposed sensible heat flux. The model-predicted temperature profile further agrees quite well with aircraft data for the case of lower imposed heat flux. However, the relative humidity values predicted by the model are lower compared with the aircraft data. The model-predicted humidity profiles are only in partial agreement with the lidar data. The results of this study suggest that the explicitly resolved energetic eddies seem to provide the correct forcing necessary to produce good agreement with observations for the case of an imposed sensible heat flux of 0.1 K m s^–1 at the surface.     

西藏地面太阳光谱观测

通过使用德国TriOS公司生产的RAMSES-ACC-UV/VIS光谱仪,在2016—2017年对西藏四个地区(拉萨、林芝、阿里和定日)进行了阶段性的太阳光谱(波长280—950 nm)实地观测。初步研究了西藏四个地区地面太阳光谱强度、光谱曲线特征以及光谱随时间的变化等,结果显示在本次观测期间,2017年7月21日(晴天)当地正午(北京时间13点58分)拉萨晴天光谱在476.6 nm波长处出现强度最高,峰值达到2.05 W?m~(-2)?nm~(-1)。同时对比了观测期间拉萨与定日、拉萨与林芝的当地正午晴天太阳光谱特征,对比结果表明:定日光谱强度高于拉萨,拉萨光谱强度高于林芝。定日光谱曲线平滑程度高于拉萨,拉萨光谱曲线平滑程度高于林芝,主要由水汽、氧气吸收造成。     

A wind resource assessment around large mountain masses: The speed-up effect

The wind potential around an intensely mountainous area has been studied and an experimental analysis is presented the output of which could be used in the wind farm planning procedure aiming at maximization of the wind power production output of an area. The wind speed of a chosen site of Central Greece was studied based on field measurements around a large mountainous area of Central Greece. Understanding flow in the foothills and the wider area of the mountains is of great importance for estimating wind resource in rough terrain. In this article, special focus was given to the speed-up effect and forced air flow around mountainous masses.     

The influence on the radioxenon background during the temporary suspension of operations of three major medical isotope production facilities in the Northern Hemisphere and during the start-up of another facility in the Southern Hemisphere

Medical isotope production facilities (MIPF) have recently been identified to emit the major part of the environmental radioxenon measured at many globally distributed monitoring sites deployed to strengthen the radionuclide component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification regime. Efforts to raise a global radioxenon emission inventory revealed that the yearly global total emission from MIPF’s is around 15 times higher than the total radioxenon emission from nuclear power plants (NPP's).Given that situation, from mid 2008 until early 2009 two out of the ordinary hemisphere-specific events occured:1) In the Northern hemisphere, a joint temporary suspension of operations of the three largest MIPF's made it possible to quantify the effects of the emissions related to NPP’s. The average activity concentrations of ¹³³Xe measured at a monitoring station close to Freiburg, Germany, went down significantly from 4.5 ± 0.5 mBq/m³ to 1.1 ± 0.1 mBq/m³ and in Stockholm, Sweden, from 2.0 ± 0.4 mBq/m³ to 1.05 ± 0.15 mBq/m³.2) In the Southern hemisphere the only radioxenon-emitting MIPF in Australia started up test production in late November 2008. During eight test runs, up to 6.2 ± 0.2 mBq/m³ of ¹³³Xe was measured at the station in Melbourne, 700 km south-west from the facility, where no radioxenon had been observed before, originating from the isotopic production process.This paper clearly confirms the hypothesis that medical isotope production facility are at present the major emitters of radioxenon to the atmosphere. Suspension of operations of these facilities indicates the scale of their normal contribution to the European radioxenon background, which decreased two to four fold. This also gives a unique opportunity to detect and investigate the influence of other local and long distance sources on the radioxenon background. Finally the opposing effect was studied: the contribution of the start-up of a renewed radiopharmaceutical facility to the build up of a radioxenon background across Australia and the Southern hemisphere.     

In-field radon measurement in water: a novel approach

This paper presents a novel approach of measuring radon in-water in the field by inserting a MEDUSA gamma-ray detector into a 210 L or 1000 L container. The experimental measurements include investigating the effect of ambient background gamma-rays on in-field radon measurement, calibrating the detector efficiency using several amounts of KCl salt dissolved in tap water, and measuring radon in borehole water. The results showed that there is fairly good agreement between the field and laboratory measurements of radon in water, based on measurements with Marinelli beakers on a HPGe detector. The MDA of the method is 0.5 Bq L⁻¹ radon in-water.