Inter-comparison of radon detectors for one to four week measurement periods.

Seven different types of radon detectors (Atmos 12 dpx, RAD7, RStone, Sun Nuclear 1028, Ramon 2.2, Canary and CR-39) were compared for exposure periods of 1, 2, 3 and 4 weeks. The comparison was conducted under two conditions: (a) in a purpose-built radon chamber with an average radon concentration of 2560 Bq m(-3) (b) in a home environment with a radon concentration of 57 Bq m(-3), in both cases measured by the reference detector (Atmos 12 dpx) with a ±10% uncertainty range. In (a) 5 out of 8 detectors recorded radon concentrations within the Atmos uncertainty range and all detectors recorded within ±15%; in (b) 3 out of 9 detectors recorded within the Atmos uncertainty range and 6 out of 9 measured within ±20%, for a 4 week measurement. The results from this study show that radon surveys can be conducted for shorter periods than the recommended 3 months where a rapid indication is needed of whether the radon concentration is above the reference level, such as when assessing the concentration during and after remediation work.

Global occurrence of Torque teno virus in water systems.

Bacterial indicator organisms are used globally to assess the microbiological safety of waters. However, waterborne viral outbreaks have occurred in drinking water systems despite negative bacterial results. Using viral markers may therefore provide more accurate health risk assessment data. In this study, fecal, wastewater, stormwater, surface water (fresh and salt), groundwater, and drinking water samples were analyzed for the presence or concentration of traditional indicators, innovative indicators and viral markers. Samples were obtained in the United States, Italy, and Australia and results compared to those reported for studies conducted in Asia and South America as well. Indicators included total coliforms, Escherichia coli, enterococci, male-specific coliphages, somatic coliphages and microviradae. Viral markers included adenovirus, polyomavirus, and a potential new surrogate, Torque teno virus (TTV). TTV was more frequently found in wastewaters (38-100%) and waters influenced by waste discharges (25%) than in surface waters used as drinking water sources (5%). TTV was also specific to human rather than animal feces. While TTV numbers were strongly correlated to other viral markers in wastewaters, suggesting its utility as a fecal contamination marker, data limitations and TTV presence in treated drinking waters demonstrates that additional research is needed on this potential viral indicator.

Are microbial indicators and pathogens correlated? A statistical analysis of 40 years of research.

Indicator organisms are used to assess public health risk in recreational waters, to highlight periods of challenge to drinking water treatment plants, and to determine the effectiveness of treatment and the quality of distributed water. However, many have questioned their efficacy for indicating pathogen risk. Five hundred and forty cases representing independent indicator-pathogen correlations were obtained from the literature for the period 1970-2009. The data were analyzed to assess factors affecting correlations using a logistic regression model considering indicator classes, pathogen classes, water types, pathogen sources, sample size, the number of samples with pathogens, the detection method, year of publication and statistical methods. Although no single indicator was identified as the most correlated with pathogens, coliphages, F-specific coliphages, Clostridium perfringens, fecal streptococci and total coliforms were more likely than other indicators to be correlated with pathogens. The most important factors in determining correlations between indicator-pathogen pairs were the sample size and the number of samples positive for pathogens. Pathogen sources, detection methods and other variables have little influence on correlations between indicators and pathogens. Results suggest that much of the controversy with regards to indicator and pathogen correlations is the result of studies with insufficient data for assessing correlations.

Performance evaluation of a constructed wetland treating high-ammonium primary domestic wastewater effluent.

An investigation of a top-loading, vertical-flow, submerged-bed constructed wetland system subject to a New York State discharge permit, of mineral nitrogen transformations occurring within the wetland units, and of the effects of local environment on system performance indicated 100% removal of biochemical oxygen demand (BOD) and mean 99.0 +/- 1.1% removal of ammonium (NH4(+)). The wetland system, located in Highland, New York, treats primary domestic wastewater effluent and consists of four beds presently operated in series. Influent and effluent samples from each of the four treatment units were analyzed for BOD, ammonium-nitrogen (NH4(+)-N), nitrate-nitrogen (NO3(-)-N), and nitrite-nitrogen (NO2(-)-N). During the study, mean influent wastewater concentrations were 170.8, 3.1, and 0.015 mg/L for NH4(+)-N, NO3(-)-N, and NO2(-)-N, respectively. Mean effluent concentrations of NH4(+)-N, NO3(-)-N, and NO2(-)-N were 1.9, 4.2, and 0.002 mg/L, respectively.

New roughness parameter for the characterization of regularly textured or ordered patterned superhydrophobic surfaces.

Surface geometry affects strongly superhydrophobic behavior. To characterize the effect, roughness as a comprehensive geometrical parameter is used, but this parameter in its general mathematic expression cannot reflect exactly such a geometrical effect, in particular, for the regularly textured or ordered patterned superhydrophobic surfaces. In this study, we propose a new parameter to mathematically describe roughness for such superhydrophobic surfaces. On the basis of this parameter, an ideal surface texture with the maximum roughness for achieving the superhydrophobicity is suggested, which is consistent with the previous experimental observations and theoretical considerations.

Using a weight-of-evidence approach for management of watersheds.

This research used a weight-of-evidence approach to evaluate sources of contaminants in a drinking water watershed that serves as part of the City of Boston's water supply. The approach incorporated land use analysis using GIS, sanitary surveys, traditional water quality monitoring and microbial source tracking (MST) tools. Case-study tributaries were selected based on elevated faecal coliform counts. Land use analysis and sanitary surveys were used to identify suspected microbial sources, including residential septic systems, agricultural animal operations, commercial/industrial operations and wildlife activity. Sampling sites were selected to hydrologically isolate potential contamination sources. Samples were collected seasonally over 1 year and analysed for traditional and MST parameters. Results demonstrated that both septic systems and a horse stable were contributing microbial loads in the first tributary. In the second tributary, septic systems from the townhouses were contributing microbial loads while a plant nursery was contributing organic matter. This evidence was used to evaluate best management practices to mitigate the contamination.

Phylogeny of prokaryotes and chloroplasts revealed by a simple composition approach on all protein sequences from complete genomes without sequence alignment.

The complete genomes of living organisms have provided much information on their phylogenetic relationships. Similarly, the complete genomes of chloroplasts have helped to resolve the evolution of this organelle in photosynthetic eukaryotes. In this paper we propose an alternative method of phylogenetic analysis using compositional statistics for all protein sequences from complete genomes. This new method is conceptually simpler than and computationally as fast as the one proposed by Qi et al. (2004b) and Chu et al. (2004). The same data sets used in Qi et al. (2004b) and Chu et al. (2004) are analyzed using the new method. Our distance-based phylogenic tree of the 109 prokaryotes and eukaryotes agrees with the biologists "tree of life" based on 16S rRNA comparison in a predominant majority of basic branching and most lower taxa. Our phylogenetic analysis also shows that the chloroplast genomes are separated to two major clades corresponding to chlorophytes s.l. and rhodophytes s.l. The interrelationships among the chloroplasts are largely in agreement with the current understanding on chloroplast evolution.

Determination of self-absorption corrections for gamma analysis of environmental samples: comparing gamma-absorption curves and spiked matrix-matched samples.

Accurate determination of the massic activity of gamma-emitting radionuclides in environmental samples, particularly sediments and soils, cannot be achieved without taking into account sample self-absorption. The extent of self-absorption in the sample will depend on a number of factors including sample composition, density, sample size and gamma-ray energy. The preferred method for correcting for this effect is to use spiked or natural matrix reference materials that match each sample type to be analysed. However, for laboratories that must measure a wide variety of sample matrices this method is too costly and time-consuming. Another technique commonly used is to make direct gamma-ray transmission measurements for each sample. This method, while more practical, still requires a minimum of three measurements to be made for each sample analysed. A more convenient method is to prepare sets of gamma-absorption curves. This approach involves making a series of direct transmission measurements for samples of varying densities but similar type. Sets of matching samples, both spiked and unspiked, were prepared and density correction factors determined using the direct transmission method and the spiked sample approach. It was found that, for soil and sediment samples, these two methods typically differed by 5-9% for higher energy gamma rays and by 12-15% for the 59.54 keV 241Am peak. Gamma-absorption curves were also derived and, for the admittedly limited dataset, 95% confidence intervals of +/-7% for the curve generated using the spiked samples method were obtained.

[Picking up and analysis of the surface myoelectric signals of respiratory muscule].

In this paper, we introduce the technique used to obtain the surface diaphragmatic EMG and monitor respiratory activity. The signals are picked up from the ECG electrodes. By using an ECG masking system based on a digital processor, the dominant effect of the ECG (that is R-wave, P-wave and T-wave) was removed. Initial clinical measurements indicate this EMG method is more direct and effective than others for monitoring respiratory activity. It is hoped that this method can be used to monitor the development of respiratory function.

Metabolite formation and toxicity measurements in evaluating bioremediation of a jet-fuel-contaminated aquifer.

The metabolic capabilities of subsurface, jet-fuel-contaminated, aquifer microbial communities were characterized using an ecological approach to biotreatment assessment. A multifaceted experimental design was used that incorporated quantification of metabolite formation and toxicity screening along with the typical microbial activity measurements and pollutant degradation measurements used for assessing bioremediation potential. For select experiments, dissolved oxygen levels and pH in microcosm systems were also monitored. Results suggest that a sizable, metabolically active microbial community exists in both contaminated and uncontaminated areas of the study site. Time course metabolism analyses indicated that the microbial communities were capable of degrading all three test compounds (amino acids, decane, and toluene) without any apparent adaptation period. Measurements of mineralization, cellular uptake, and metabolite formation indicated that metabolite formation was the predominant fate of the target pollutants in the microcosms. The results of toxicity screening time courses indicated that under oxygen-limiting conditions, the potential for the accumulation of toxic, acidic metabolites that could adversely affect the rates and extent of bioremediation existed. The experimental results indicate that the microbial communities at the site possess the metabolic potential for in situ biodegradation of the jet fuel. Care must be taken in the design of an in situ biodegradation treatment system (for this site and perhaps other petroleum-contaminated aquifers) to avoid the development of microaerophilic or oxygen-depleted zones, which could result in possible self-poisoning owing to acidic metabolite accumulation.

Variations in the concentration of plutonium, strontium-90 and total alpha-emitters in human teeth collected within the British Isles.

Concentrations of plutonium-239, plutonium-240, strontium-90 and total alpha-emitters have been measured in children's teeth collected throughout Great Britain and Ireland. The concentrations of plutonium and strontium-90 were measured in batched samples, each containing approximately 50 teeth, using low-background radiochemical methods. The concentrations of total alpha-emitters were determined in single teeth using alpha-sensitive plastic track detectors. The results showed that the average concentrations of total alpha-emitters and strontium-90 were approximately one to three orders of magnitude greater than the equivalent concentrations of plutonium-239,240. Regression analyses indicated that the concentrations of plutonium, but not strontium-90 or total alpha-emitters, decreased with increasing distance from the Sellafield nuclear fuel reprocessing plant-suggesting that this plant is a source of plutonium contamination in the wider population of the British Isles. Nevertheless, the measured absolute concentrations of plutonium (mean = 5 +/- 4 mBq kg-1 ash wt.) were so low that they are considered to present an insignificant radiological hazard.

A comparison of microbial community characteristics among petroleum-contaminated and uncontaminated subsurface soil samples.

Measurements of microbial community size, including total cell counts and specific degrader enumerations, were conducted on subsurface soil samples from both petroleum-contaminated and pristine aquifers. Samples were collected from both uncontaminated and contaminated areas of the petroleum-contaminated sites. In pristine and uncontaminated samples, total cell counts (acridine orange direct counts) were related to depth. The deeper samples contained smaller total microbial populations. However, indices of microbial activity varied considerably from sample to sample and probably reflect soil and site heterogeneity. Exposure to petroleum contamination apparently altered the microbial community structure. In samples exposed to low levels of contaminants as vapors and/or dissolved phases (ppb concentrations), and not free product, the toluene-specific degrader populations were larger at greater depths, and the numbers of amino acid-specific degraders were highly correlated to the numbers of decane-specific degraders, indicating that petroleum-adapted microbial communities were present in the contaminated samples. In highly contaminated samples, total microbial population densities decreased with increasing depth; however, microbial activity tended to increase with depth. These results indicate that petroleum contaminants exert toxic effects on the active microbial community at high exposures and enrich specific degraders at ppb levels of dissolved contaminants.

Oral contraceptives and cycle control: a critical review of the literature.

Control of spotting and breakthrough bleeding and absence of withdrawal bleeding, collectively termed cycle control, is the single most important determinant of whether a new user of oral contraceptives (OCs) will continue this method. However, information about different OC preparations and how they affect such problems, including the effects of progestogen and estrogen phasing and the components of these hormones, is scant and confusing. Studies cited in this report reveal highly variable rates of bleeding problems in women taking OCs: after 6 months of OC use, the prevalence of spotting varied between 0% and 8.5%; of breakthrough bleeding, 0% and 12.2%; and of amenorrhea, 0% and 5.8%. At least some of this variation is attributable to differing study populations and cultures, study designs, and the manner in which data were collected and reported. However, methodologic weaknesses were common, often involving lack of randomization and blinding, and attrition rates were high. Despite these limitations, it is clear that the frequency of bleeding problems decreases with continuing use of OCs, emphasizing the need for patient reassurance about the transient nature of these problems. In addition, gestodene-containing preparations appear to offer better cycle control than do desogestrel-containing preparations and levonorgestrel-containing preparations better control than norethindrone-containing preparations. However, the strongest lesson to emerge is the need for more rigorous studies to adequately address questions of comparative bleeding problems, particularly with newer triphasic formulations. These conclusions underscore the importance of counseling new OC users about the possibility of bleeding problems, reassuring them that most such problems are temporary, and, that if compliance is maintained, these will not impair contraceptive efficacy.

Shoulder torque changes in the swimming athlete.

Torque production was assessed in the shoulders of competitive men and women swimmers for the motions of abduction, adduction, and external and internal rotation. Testing was performed on the Cybex II dynamometer and the results were compared to controls. In addition, the ratios of torque development for adduction:abduction and external rotation:internal rotation were evaluated. The results demonstrated a statistically significant increase in torque production in swimmers for most motions tested. Statistically significant ratio shifts were also noted. The ratio of adduction:abduction increased and that for external rotation:internal rotation decreased. We think these shifts in the torque ratios in swimmers' shoulders resulted from sport-specific repetitive activity that emphasizes adduction and internal rotation.

Isokinetic torque imbalances in the rotator cuff of the elite water polo player.

The specific repetitive activity of water polo, like baseball pitching, emphasizes adduction and internal rotation. This study used the Cybex II to evaluate the isokinetic strength of the rotator cuff in elite water polo players and in a group of control subjects. The water polo players were significantly stronger than the controls. Of greater importance was the confirmation of imbalances in the rotator cuff force couples of adduction/abduction and external/internal rotation. These changes are similar to those reported for pitchers. The adductors in the water polo group had gained in relative strength resulting in an increase in the adduction/abduction ratio to about 2:1. The internal rotators had gained in relative strength resulting in a decrease in the external/internal ratio to about 0.6:1. For both force couples the differences are more apparent at a slow speed. Side-to-side differences were not significant.