Unusual segregation for 11q;22q parental translocation in a triplet pregnancy: Prenatal diagnosis in chorionic villi and amniotic fluid

The prenatal diagnosis of an 11q;22q translocation in a triplet pregnancy detected at the time of chorionic villus sampling (CVS) because of advanced maternal age is reported. Karyo-types obtained from two apparently different CV samples showed the balanced form of translocation, while the one obtained from a third empty sac showed the unbalanced form: 46, XX, −22, + der(22)t(11;22). Second-trimester amniocentesis confirmed the balanced translocation in one of the two viable fetuses and a normal karyotype in the other. The detected karyotypes derived from two different types of meiotic segregation, alternate and adjacent 1. To our knowledge, this is the first reported case of an unbalanced karyotype not due to a 3:1 meiotic segregation of this specific translocation.     

Adequacy of Visually Classified Particle Count Statistics From Regional Stream Habitat Surveys1

Abstract: Streamlined sampling procedures must be used to achieve a sufficient sample size with limited resources in studies undertaken to evaluate habitat status and potential management‐related habitat degradation at a regional scale. At the same time, these sampling procedures must achieve sufficient precision to answer science and policy‐relevant questions with an acceptable and statistically quantifiable level of uncertainty. In this paper, we examine precision and sources of error in streambed substrate characterization using data from the Environmental Monitoring and Assessment Program (EMAP) of the U.S. Environmental Protection Agency, which uses a modified “pebble count” method in which particle sizes are visually estimated rather than measured. While the coarse (2?) size classes used in EMAP have little effect on the precision of estimated geometric mean (D_gm) or median (D₅₀) particle diameter, variable classification bias among observers can contribute as much as 0.3?, or about 15‐20%, to the root‐mean‐square error (RMSE) of D_gm or D₅₀ estimates. D_gm and D₅₀ estimates based on EMAP data are nearly equal when fine sediments (<2 mm) are excluded, but otherwise can differ by up to a factor of 2 or more, with D_gm < D₅₀ for gravel‐bed streams. The RMSE of reach‐scale particle size estimates based on visually classified particle count data from EMAP surveys, including variability associated with reoccupying unmarked sample reaches during revisits, is up to five to seven times higher than that reported for traditional measured pebble counts by multiple observers at a plot scale. Nonetheless, a variance partitioning analysis shows that the ratio of among site to revisit variance for several EMAP substrate metrics exceeds 8 for many potential regions of interest, suggesting that the data have adequate precision to be useful in regional assessments of channel morphology, habitat quality, or ecological condition.     

Nonparametric Monte Carlo Simulation for Flood Frequency Curve Derivation: An Application to a Korean Watershed1

Abstract: A mix of causative mechanisms may be responsible for flood at a site. Floods may be caused because of extreme rainfall or rain on other rainfall events. The statistical attributes of these events differ according to the watershed characteristics and the causes. Traditional methods of flood frequency analysis are only adequate for specific situations. Also, to address the uncertainty of flood frequency estimates for hydraulic structures, a series of probabilistic analyses of rainfall‐runoff and flow routing models, and their associated inputs, are used. This is a complex problem in that the probability distributions of multiple independent and derived random variables need to be estimated to evaluate the probability of floods. Therefore, the objectives of this study were to develop a flood frequency curve derivation method driven by multiple random variables and to develop a tool that can consider the uncertainties of design floods. This study focuses on developing a flood frequency curve based on nonparametric statistical methods for the estimation of probabilities of rare floods that are more appropriate in Korea. To derive the frequency curve, rainfall generation using the nonparametric kernel density estimation approach is proposed. Many flood events are simulated by nonparametric Monte Carlo simulations coupled with the center Latin hypercube sampling method to estimate the associated uncertainty. This study applies the methods described to a Korean watershed. The results provide higher physical appropriateness and reasonable estimates of design flood.     

Emission of volatile organic compounds (VOC) from tropical plant species in India

Foliar emission of volatile organic compounds (VOC) from common Indian plant species was measured. Dynamic flow enclosure technique was used and the gas samples were collected onto Tenax-GC/Carboseive cartridges. The Tenax-GC/Carboseive cartridges were attached to the thermal disorber sample injection system and the gas sample was analysed using gas chromatography (GC) with flame ionisation detection (FID). Fifty-one local plant species were screened, out of which 36 species were found to emit VOC (4 high emitter; 28 moderate emitter; and 4 low-emitter), while in the remaining 15 species no VOC emission was detected or the levels of emission were below detection limit (BDL). VOC emission was found to vary from one species to another. There was a marked seasonal and diurnal variation in VOC emission. The minimum and maximum VOC emission values were < 0.1 and 87 microgg(-1) dry leaf h(-1) in Ficus infectoria and Lantana camara respectively. Out of the 51 plant species studied, 13 species are reported here for the first time. Among the nine tree species (which were selected for detailed study), the highest average hourly emission (9.69+/-8.39 microgg(-1) dry leaf) was observed in Eucalyptus species and the minimum in Syzygium jambolanum (1.89+/-2.48 microgg(-1) dry leaf). An attempt has been made to compare VOC emission from different plant species between present study and the literature (tropical and other regions).     

How many samples are required? Evaluating a model for verification of carbon sequestration in a hybrid poplar buffer strip

A model is developed to predict annual and total above-ground carbon storage within a hybrid poplar stream buffer. The regression model predicts tree wet weight based upon circumference at breast-height (137 cm) with an r-square value of 0.9922. Carbon storage in above-ground biomass is estimated to be 3.57 to 3.71 metric tons per hectare, with a measured annual increment of 0.92 to 1.37 metric ton per hectare per year. The variability of carbon storage within this biological system, including soil organic matter, is explored, and the number of samples required to achieve a desired level of statistical certainty are predicted. As has been investigated previously for other biological systems (Garten and Wullschleger, 1999), the study shows that a prohibitively large number of samples must be taken in order to achieve high degrees of certainty about mean carbon storage values. The study also shows, however, that mean values with somewhat greater uncertainties can easily be achieved with much smaller sample sizes. Thus carbon sequestration verification might be accomplished cost-effectively if the degree of certainty required is not unrealistically high for highly variable natural systems.     

无除湿预处理采样法测定烟气中低浓度SO2

针对海水脱硫后的烟气具有SO2浓度低、湿度大、温度低的特点，提出了在烟道内无需除湿预处理的直接采样测定SO2的方法，解决了国标法进行除湿采样或使用较先进仪器直接脱水测定带来的测定结果偏低问题。实际应用表明，谊法比在烟道外使用的除湿法更加准确、经济。     

Graphical effluent quality control for compliance monitoring: What is a violation?

Demonstration of compliance with discharge (effluent) requirements suffers because Discharge Monitoring Reports (DMRs) give neither the discharger nor the regulator information on the process mean which ensures compliance. To obtain this information, a simple graphical method is presented which takes into account process variability. This technique provides quality control specifications for the monitoring data and the process itself.     

Sampling of airborne polycyclic aromatic hydrocarbons with semipermeable membrane devices

Semipermeable membrane devices (SPMDs) are nowadays used as passive samplers of organic pollutants. The knowledge of the sampling rate values (R_S) of each substance trapped on membranes is necessary to calculate their average concentration. Here we calculate R_S values for 16 polycyclic aromatic hydrocarbons using the comparison of active sampling method results and the amounts sequestered by SPMDs at varying exposure times.Selected article from the Regional Symposium on Chemistry and Environment, Krusevac, Serbia, June 2003, organized by Dr. Branimir Jovancicevic.