Estimating the population size with a behavioral response in capture-recapture experiment

A new estimating procedure is suggested to estimate the population size in a capture-recapture experiment. The capture intensities for first-capture and recapture are allowed to be different and time dependent but they are assumed to be proportional. It is shown that the information on the proportionality constant is crucial to the estimation of the population size. Sensitivity analysis with a misspecification of the proportionality constant is conducted. The method has also been extended to the case with an unknown proportionality. A real example is given.     

Modelling of a large-scale urban contamination situation and remediation alternatives

The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes the first of two modelling exercises, which was based on Chernobyl fallout data in the town of Pripyat, Ukraine. Modelling endpoints for the exercise included radionuclide concentrations and external dose rates at specified locations, contributions to the dose rates from individual surfaces and radionuclides, and annual and cumulative external doses to specified reference individuals. Model predictions were performed for a “no action” situation (with no remedial measures) and for selected countermeasures. The exercise provided a valuable opportunity to compare modelling approaches and parameter values, as well as to compare the predicted effectiveness of various countermeasures with respect to short-term and long-term reduction of predicted doses to people.     

Associations of fat mass and lean mass with bone mineral density differ by levels of persistent organic pollutants: National Health and Nutrition Examination Survey 1999-2004

Persistent organic pollutants (POPs), xenobiotics that accumulate in fat tissue, may impair bone metabolism. We studied (1) the association of bone mineral density (BMD) with POPs and (2) whether associations of fat mass (FM) or lean mass (LM), two components of body composition, with BMD differed depending on levels of POPs. Participants aged ?20 in the National Health and Nutrition Examination Survey 1999-2004 were included (n = 2769). Eight POPs with detection rate ?80% and three skeletal subregions (left arm, pelvis, and right leg) were selected. All analyses were stratified by gender and age (cutpoint 50 years or more). POPs at background concentrations were mostly unassociated with BMD. However, the associations of FM and LM with BMD depended on POPs concentrations, in particular with BMD of the left arm (usually not weight-bearing) in postmenopausal women. When POPs concentrations were low, FM showed inverse associations with BMD while LM showed positive associations. However, when POPs levels were high, FM showed positive associations with BMD while the positive associations between LM and BMD weakened. POPs may biologically modify the associations of FM and LM with BMD, especially among postmenopausal women, possibly explaining inconsistent associations between FM and BMD in previous epidemiological studies.     

Characterization of char derived from various types of solid wastes from the standpoint of fuel recovery and pretreatment before landfilling

Carbonization is a kind of pyrolysis process to produce char from organic materials under an inert atmosphere. In this work, chars derived from various solid wastes were characterized from the standpoint of fuel recovery and pretreatment of waste before landfilling. Sixteen kinds of municipal and industrial solid wastes such as residential combustible wastes, non-combustible wastes, bulky wastes, construction and demolition wastes, auto shredder residue, and sludges were carbonized at 500 degrees C for 1h under nitrogen atmosphere. In order to evaluate the quality of char as fuel, proximate analysis and heating value were examined. The composition of raw waste had a significant influence on the quality of produced char. The higher the ratio of woody biomass in waste, the higher heating value of char produced. Moreover, an equation to estimate heating value of char was developed by using the weight fraction of fixed carbon and volatile matter in char. De-ashing and chlorine removal were performed to improve the quality of char. The pulverization and sieving method seems to be effective for separation of incombustibles such as metal rather than ash. Most char met a 0.5 wt% chlorine criterion for utilization as fuel in a shaft blast furnace after it was subjected to repeated water-washing. Carbonization could remove a considerable amount of organic matter from raw waste. In addition, the leaching of heavy metals such as chrome, cadmium, and lead appears to be significantly suppressed by carbonization regardless of the type of raw waste. From these results, carbonization could be considered as a pretreatment method for waste before landfilling, as well as for fuel recovery.     

Formation and removal of PCDD/Fs in a municipal waste incinerator during different operating periods

The PCDD/F concentrations and removal efficiencies achieved with air pollution control devices (APCDs) during different operating periods (start-up, normal operation, and shut-down) at an existing municipal waste incinerator (MWI) in Taiwan are evaluated via stack sampling and analysis. The MWI investigated is equipped with electrostatic precipitators (EP), wet scrubbers (WS), and selective catalytic reduction system (SCR) as APCDs. The sampling results indicate that the PCDD/F concentrations at the EP inlet during start-up period were 15 times higher than that measured during normal operation period. The PCDD/F concentration observed at shut-down period was close to that measured at normal operation period. The CO concentration was between 400 and 1000 ppm during start-up period, which was about 50 times higher compared with the normal operation. Hence, combustion condition significantly affected the PCDD/F formation concentration during the waste incineration process. In addition, the distributions of the PCDD/F congeners were similar at different operating periods. During the normal operation and shut-down periods, the EP decreases the PCDD/F concentration (based on TEQ) by 18.4-48.6%, while the removal efficiency of PCDD/Fs achieved with SCR system reaches 99.3-99.6%. Nevertheless, the PCDD/F removal efficiency achieved with SCR was only 42% during the 19-h start-up period due to the low SCR operating temperature (195 degrees C).     

Reduced sulfur compounds in ambient air surrounding an industrial region in Korea

The atmospheric concentrations of several reduced sulfur compounds (RSCs) including H(2)S, CH(3)SH, DMS, CS(2), and DMDS were measured concurrently from a series of field campaigns covering multiple locations in the surroundings of a large industrial region (August 2004 to September 2005). These field studies have been designed and undertaken to inspect the concentrations of RSCs in ambient air. The RSC concentrations were found to occur in a highly variable range. H(2)S (1.06 +/- 2.07 ppb) was found to be the most abundant RSC followed by CS(2) (0.84 +/- 0.54 ppb), DMDS (0.36 +/- 1.21 ppb), DMS (0.24 +/- 0.83 ppb), and CH(3)SH (0.11 +/- 0.23 ppb). The RSC levels measured at the study area were comparable to those observed previously from other polluted environmental settings. When these RSC data were examined further in terms of spatial (industrial vs. non-industrial sites) and seasonal (summer vs. winter seasons) grouping schemes, differences in their concentration levels were statistically insignificant in most cases. In contrast, there were fairly strong variations in temporal patterns over a diurnal cycle. If these RSC concentration data were converted to diagnose the malodor strengths, their effects were in most cases insignificant with minor contribution towards odor nuisances.     

Formaldehyde and carbon dioxide air concentrations and their relationship with indoor environmental factors in daycare centers

The aim of this study was to measure the air concentrations of carbon dioxide (CO₂) and formaldehyde (HCHO) in daycare centers to determine relevant influencing factors, including temperature, relative humidity (RH), type of facility, number of children, type of ventilation system, ventilation time, and air cleaning system. The authors measured HCHO, CO₂, temperature, and RH in the center of classrooms in 289 daycare centers. Spearman’s correlation and Mann–Whitney analyses were used to examine the relationships and differences in HCHO and CO₂ for varying temperatures, RH values, and categorical indoor environmental factors. There were no significant differences in the HCHO and CO₂ air concentrations with varying numbers of children, ventilation times, or ventilation and air cleaning system types. However, both the HCHO and CO₂ air concentrations were significantly different for varying RH values, which were divided into five categories (p < 0.001). Only the HCHO air concentrations were significantly different for varying temperatures, which were divided into five categories (p < 0.001). Significant correlations were found between HCHO air concentrations and the temperature (r = 0.35, p < 0.0001), RH (r = 0.51, p < 0.0001), and CO₂ (r = 0.36, p < 0.0001). The study results support maintaining an appropriate temperature and RH range for reducing airborne HCHO in daycare centers. Further research is needed to elucidate the precise mechanisms responsible for the relationships observed in this study.

Implications: Data from 289 daycare centers in Seoul, South Korea, indicate that HCHO concentrations show a positive correlation with indoor temperature and relative humidity. This indicates that keeping temperatures low will help keep HCHO concentrations low, by both a direct and an indirect effect, since low temperatures also cause low relative humidity.     

Questionnaire and onsite survey on municipal solid waste composting in Sri Lanka

This study was conducted to evaluate the composting processes in Sri Lanka and to identify essential improvements. The study consisted of a questionnaire survey, field observations, and interviews. The main shortcomings identified by this study were: no source separation at origin, and no monitoring for temperature, moisture, stability, or maturity during processes of composting. These problems hinder the smooth operation of the composting processes and lead to low demand for compost. Based on the findings, the recommendations for increasing the demand for compost are performing source separation during waste collections, improvement of processes by monitoring the temperature and moisture, and marketing compost so as to improve the popularity of the compost among farmers.     

Distributed Hydrologic Modeling in the Suburban Landscape: Assessing Parameter Transferability from Gauged Reference Catchments1

Mittman, Tamara, Lawrence E. Band, Taehee Hwang, and Monica Lipscomb Smith, 2012. Distributed Hydrologic Modeling in the Suburban Landscape: Assessing Parameter Transferability from Gauged Reference Catchments. Journal of the American Water Resources Association (JAWRA) 48(3): 546-557. DOI: 10.1111/j.1752-1688.2011.00636.x Abstract: Distributed, process-based models of catchment hydrologic response are potentially useful tools for the assessment of Low Impact Development (LID) techniques in urbanized catchments. Their application is often limited, however, by the lack of continuous streamflow records to calibrate poorly constrained parameters. This article examines the transferability of soil and groundwater parameters from a forested reference catchment to a nearby suburban catchment. We use the Regional Hydro-Ecologic Simulation System (RHESSys) to develop hydrologic models of one gauged forested and one ungauged suburban catchment within the Baltimore Ecosystem Study (BES) study area. We use a parameter uncertainty framework to calibrate soil and groundwater parameters for the forested catchment, and discrete measurements of streamflow from the suburban catchment to assess parameter transferability. Results indicate that the transfer of soil and groundwater parameters from forested reference to nearby suburban catchments is viable, with performance measures for the suburban catchment often exceeding those for the forested catchment. We propose that the simplification of hydrologic processes in urbanized catchments may account for the increase in model performance in the suburban catchment.     

Outdoor tobacco smoke exposure at the perimeter of a tobacco-free university

There are few studies measuring exposure to outdoor tobacco smoke (OTS). Tobacco users often gather at the boundaries of tobacco-free campuses, resulting in unintended consequences. The objective of this study was to measure exposure levels from OTS on sidewalks bordering a tobacco-free university campus. Data were collected while walking along a sidewalk adjacent to a medium traffic road between May and August 2011. Monitoring occurred during “background,” “stop,” and “walk-through” conditions at and near hot spot area to measure fine particulate matter (<2.5 μm; PM_2.5) from OTS using a portable aerosol monitor. The average PM_2.5 levels during stop and walk-through conditions were significantly higher than during background conditions. PM_2.5 peak occurrence rate and magnitude of peak concentration were significantly different depending on smoking occurrence. The peak occurrence rate during the stop condition was 10.4 times higher than during the background condition, and 3.1 times higher than during the walk-through condition. Average peak PM_2.5 concentrations during the stop condition were 48.7% higher than during the background condition. In conclusion, individuals could be exposed to high levels of PM_2.5 when stopping or even passing by smokers outdoors at the perimeter of tobacco-free campuses. The design and implementation of tobacco-free campus policies need to take into account the unintended consequences of OTS exposure at the boundaries.

Implications:In this study, outdoor tobacco smoke (OTS) exposure was measured at the perimeter of tobacco-free campus. OTS exposure could be determined by peak analysis. Peak occurrence rate and peak concentration for OTS exposure were identified by using peak analysis. People could be exposed to high levels of PM_2.5 when standing or even passing by smokers at the perimeter of tobacco-free campus. OTS exposure measurement in other outdoor locations with smokers is needed to support outdoor smoking regulation.