Intensive Sampling Scheme Research Articles

Use of artificial sweeteners and caffeine in a population of Hanoi: An assessment by wastewater-based epidemiology

Monitoring the consumption of artificial sweeteners in the population is essential to help public health authorities understand the level of sugar consumption. There is a gap in knowledge of patterns and levels of artificial sweetener consumption in Vietnam. Using wastewater-based epidemiology (WBE), this study aims to evaluate the use of artificial sweeteners in an urban population in Hanoi, Vietnam. A total of 184 wastewater samples were collected at two sampling sites in an urban canal, receiving sewage from over 400,000 people in three different periods between 2018 and 2020. The population normalized per capita consumption of the five detected artificial sweeteners varied from 0.87 mg d−1 p−1 (sucralose) to 5.2 mg d−1 p−1 (aspartame). The daily consumption of artificial sweeteners was found to be stable throughout the week, however the consumption of artificial sweeteners was influenced by season with higher consumption in summer. Significant correlations (p < 0.01) were found among levels of artificial sweeteners and caffeine in urban canal samples, suggesting these chemicals had common sources. Population-weighted consumption load of artificial sweeteners and caffeine was compared in Vietnam, China and Australia, and the per capita consumption load mainly depended on the habitual of tea/coffee drinking in different countries. This was the first study that provided information on the artificial sweetener consumption by wastewater analysis in Vietnam. However, several sources of uncertainty (sample collection, population estimation, other sources of artificial sweeteners in wastewater, etc.) were acknowledged in this study. Further investigations on the spatial-temporal variation of artificial sweetener consumption with more intensive sampling scheme in Vietnam are recommended.

Towards the comparison of home range estimators obtained from contrasting tracking regimes: the wild boar as a case study

Traditional VHF radio-tracking is gradually being replaced by GPS tracking devices in spatial ecology studies, although both technologies continue to be used. Differences between tracking regimes (time and fix frequency) may lead to home range estimates that are not directly comparable. Our primary aim was to test the reliability of comparisons in home range estimates using different estimators (minimum convex polygon [MCP], fixed kernels [KDE] and dynamic Brownian Bridge Models [dBBMM]) and tracking regimes (see above) and to provide an empirical basis for linking VHS and GPS tracking data analysis, using the wild boar (Sus scrofa) as a study model. Data were obtained from 15 GPS-collared individuals from three areas in Mediterranean Spain. Using tracking data, we simulated different tracking regimes (approaches), from three relocations per week during the daytime to one location per hour in the case of more intensive continuous monitoring. Results suggested that MCP produces the greatest differences between approaches, while 95% kernel home range (Khr95) the lowest, both in size and utilization distribution overlap. From the 50% kernel core range (Kcr50), similar estimates were also obtained for the less intensive approaches (typical of VHF tracking regimes). Using the most intensive sampling scheme, dBBMM estimates did not differ significantly from those obtained with Khr95 for all approaches. The standardization of home range estimates is very important for wildlife management and conservation. The proposed methodology allows direct comparison among studies using different approaches for estimating home ranges.

Effect of Environmental Variation on Estimating the Bacterial Species Richness.

Estimating the species richness of microorganisms is of great importance in predicting, maintaining and managing microbial communities. Although the roles of environmental heterogeneity and geographical distance in structuring soil microbial communities have been studied intensively, the effects of environmental and spatial variation on the species richness estimation have not been examined. To this end, we have explored their effects on estimating the belowground soil bacterial species richness within a 50 ha forest dynamic plot (FDP) using a published massive sequencing dataset with intensive sampling scheme. Our resampling analyses showed that, for a given sequencing depth, increasing the sample size could significantly enhance the detection of rare species by capturing more of the environmental and spatial variation, thus obtaining higher observed and estimated species richness. Additionally, the estimates of bacterial species richness were significantly and positively correlated with environmental variation among samples, indicating that environmental filtering was the main mechanism driving the processes of community assembly for belowground soil bacterial communities in the plot. Moreover, this effect of environmental variation could be markedly alleviated when the sample size was higher than 450, and thus we predicted that there were at least 42,866 soil bacterial species based on 8,296,878 sequences from 550 samples in the whole 50 ha FDP. Furthermore, we built a power law environmental heterogeneity equation (EHE) as a decision-tool to determine an approximate sample size for comprehensively capturing the environmental gradient within a given habitat. Collectively, this work further links the inherent environmental and spatial variation to the estimation of soil bacterial species richness within a given region, and provides a useful tool of sampling design for a better understanding of microbial biogeographic patterns and estimation of microbial biodiversity.

Intermittent nasal carriage with Staphylococcus aureus within a menstrual cycle

Female sex hormones have been related to nasal Staphylococcus aureus carriage in healthy individuals; however, whether nasal staphylococcal carriage varies by menstrual cycle phase remains unknown.We sampled anterior nares of female healthcare workers twice per week for 6 consecutive menstrual cycles. We used mixed-effects Poisson regression models to determine whether intermittent carriage was associated with cycle phases in a given individual. We also performed recurrent event survival analysis to identify host factors linked to incident carriage status.Overall, we collected 754 nasal swabs over 89 consecutive person-cycles from 14 intermittent carriers. In 84 ovulation-defined menstrual cycles (715 swabs), the period prevalence of staphylococcal carriage was 58.7%, 63.1%, and 64.9% in the follicular, periovulatory, and luteal phases, respectively; these differences were not statistically significant after multivariable adjustment and correction for within-person correlation (adjusted relative risk [RR]-periovulatory 0.92, P: 0.30; luteal 1.00, P: 0.98).Using survival analysis, we identified several host factors that were associated with incident loss, gain of colonization, or both. For example, as compared to women aged 20 to 30 years, those aged 30 to 40 years were less likely to losing carriage (hazard ratio [HR]: 0.26, 95% confidence interval [CI]: 0.09, 0.80) but were as likely to regaining carriage (HR: 0.53, 95% CI: 0.21, 1.34). In comparison, being underweight (body mass index [BMI] <18.5) was significantly associated with a higher risk for regaining (HR: 1.95, 95% CI: 1.34, 1.51) and losing (HR: 1.57, 95% CI: 1.16, 2.12) colonization, indicating the alternating tendency for status changes. Personal hygiene behaviors, such as nostril cleansing habit and methods, differentially affected carriers' risk for losing or regaining staphylococcal colonization.Using an intensive sampling scheme, we found that nasal staphylococcal carriage could vary substantially over time in healthy carriers. Yet, such dynamic intraperson changes in carriage status did not depend on menstrual cycle phases but were associated with host age, BMI, and personal hygiene behavior.

Effects of rotational infrastructure within pasture-raised pig operations on ground cover, soil nutrient distribution, and bulk density

Interest in pasture-based pork products has increased significantly in recent years. However, nitrogen (N) losses resulting from these systems are common due to importation of feed, high stocking rates, and pig behavior. This study was conducted to evaluate soil inorganic N, soil-test phosphorus (STP), ground cover, and compaction changes as impacted by rotational shade, water, and feed structures in a pasture-raised pig operation over two 12-week pig occupations. Shade and watering structures were rotated weekly for 12 weeks within a rotational (mobile) scheme; data were compared to a stationary structure system as well as to a managed hay operation with no pigs. Soil samples were acquired from subplots and analyzed for distribution of inorganic N concentrations among main plot treatments, including nitrate (NO3), ammonium (NH4), and STP values. Soil inorganic N concentrations were higher in exterior subplot positions than in interior positions. This pattern was not maintained after a second pig group occupied the plots. Soil test phosphorus was unaffected by either pig occupation. Ground cover percentages were higher in control (hay) treatments than for pig treatments, however no difference was found between mobile and stationary structure treatments in either pig occupation. Soil compaction, as measured by soil bulk density, was found to be higher under permanent shade structure locations as compared to mobile and control treatments. Mobile and control compaction levels were not different for the second occupation, utilizing a more intensive sampling scheme, suggesting a benefit to the rotation of shade, water and feed infrastructure. The weekly rotation of infrastructure performed during both occupations was both labor intensive and time consuming. The observed lack of improvement in nutrient distribution to a rotational infrastructure may limit its utility in pastured-pig systems. However, further options are available that would allow the production of pasture-raised pigs while minimizing associated nutrient loading and pasture degradation.

Downstream effects of diversion dams on sediment and hydraulic conditions of Rocky Mountain streams

AbstractReduced streamflow via flow diversion has the potential to limit the sediment‐transport capacity of downstream channels and lead to accumulation of fine sediments and habitat degradation. To investigate, we examined the effects of variable levels of flow diversion on fine‐sediment deposition, hydraulic conditions and geomorphic alteration. Our study consisted of a detailed field analysis pairing reaches above and below diversion dams on 13 mountain streams in north‐central Colorado and southern Wyoming USA. Diversions are ubiquitous across the American West, yet previous comparative studies on the effects of flow diversion have yielded mixed results. Through application of strict site‐selection criteria, multiple fine‐sediment measures, and an intensive sampling scheme, this study found that channels downstream of diversions contained significantly more fine sediment and slow‐flowing habitat as compared to upstream control reaches. Susceptibility to fine‐sediment accumulation was associated with decreasing basin size, decreasing bankfull depth and smaller d84, and it appears to be magnified in streams of less than 3% slope. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Initial Genetic Evidence of Population Structure of Greenland Halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic

Greenland halibut (Reinhardtius hippoglossoides) supports one of the major groundfish fisheries of the Northwest Atlantic and its biological stock structure is an important management concern. Using nuclear DNA microsatellite markers and a combination of summary statistics and Bayesian inference, we identified two distinct stocks, both represented within the Baffin Island–West Greenland complex and in the Gulf of St. Lawrence. While a North-South pattern of genetic structure was not supported, our data suggest East-West differentiation within Baffin Bay and Davis Strait. Genetic distances between samples were not correlated with geographic distances, and some degree of intermingling of the two stocks within the same assemblages was detected. Our preliminary results warrant further investigation of the observed patterns with the support of an intensive sampling scheme.

Reduction in data collection for determination of cultivar coefficients for breeding applications

Plant breeding applications of crop simulation models require cultivar coefficients of new breeding lines. These cultivar coefficients are normally estimated from field experiments conducted under optimum conditions over several environments with elaborate data collection for each line throughout its life cycle. Such an intensive sampling scheme poorly applies to breeding lines at the early testing stages, because the number of lines is large and seed supply is limited. The objective of this study was to determine the minimum data to be collected for the estimation of cultivar coefficients of peanut lines for breeding applications of the CSM-CROPGRO-Peanut model. Nine peanut lines varying in maturity were selected for this study. Data on plant growth and development stages of these lines that were collected following the recommended procedure were obtained from a previous study. These data were used in a stepwise procedure to determine the minimum plant characteristics required for deriving the cultivar coefficients. This included both the intensity of data collection as well as the type of phenological and growth characteristics. The full versus partial data sets were then used for model calibration to derive the cultivar coefficients and an independent data set was used for model evaluation. The results showed that (i) different types of reduced phenological data resulted in the same values of the cultivar coefficients; (ii) cultivar coefficients derived from some reduced growth data sets were as good as those derived from full data collection; (iii) model calibration of cultivar coefficients derived from various types of reduced data collection worked well for all development characteristics and fairly well for the normalized root mean square error (RMSEn) values of the plant growth characteristics; and (iv) model evaluation showed good agreements between observed and simulated values for all growth and development characteristics. These results showed that it is possible to reduce the data collection for cultivar coefficients determination. The minimum data suggested is to determine two developmental stages, i.e., first flowering (R1) and harvest maturity (R8), and three plant samplings for growth analysis, i.e., around the stages of full seed (R6), physiological maturity (R7) and harvest maturity (R8).

Measuring woodpecker food: a simple method for comparing wood-boring beetle abundance among fire-killed trees

Abstract Measurements of food availability for avian insectivores are desirable, but are complicated by the range of microhabitats insects occupy and the difficulty of comparing non-standard techniques across studies. We describe an efficient method for sampling wood-boring beetle larvae, an important food of many woodpeckers, beneath the bark of fire-killed trees. The method involves taking two 225-cm2 bark samples from each tree, and provides enough information to rank most trees by relative wood-borer abundance. At two sites in the northern Rocky Mountains, we tested the reliability of this method by comparing its results to those of a more intensive sampling scheme. For 65 trees of four species, we collected eight bark samples at two different heights, 1.7 m and 6 m, and compared correlations between the smaller, ground-based sampling scheme (two bark samples) and the larger, eight-sample effort. With one exception, correlations for individual tree species ranged from 0.79 to 0.95, indicating that the...

Intensive versus Long-Term Sampling to Assess Lepidopteran Diversity in a Southern Mixed Mesophytic Forest

As biodiversity loss increases through species extinction and habitat degradation, the need to catalog what remains becomes ever more important. The time and monetary limitations of long-term biodiversity surveys become a concern as demand for biodiversity studies rises. This study was initiated to compare the efficiency of an intensive sampling scheme with a relatively long-term sampling scheme. Richness and abundance of selected moth taxa were measured in a mixed mesophytic forest habitat during a period of 8 mo for the long-term collection. An equal number of samples was taken from the same habitat during 1 mo for the intensive collection. A total of 3,155 specimens representing 314 species of moths was collected in the long-term study compared with 4,198 specimens representing 261 species in the intensive study. Sorenson's index indicated 76% species overlap between the 2 studies. Based on total species richness for this habitat, the intensive collection recovered 15% less than the long-term collection and took about half the time. The total number of species identified from both collections was 362. Because many biodiversity assessments are currently conducted on a short-term basis, studies such as this can provide entomologists with rough estimates of the percentage of biodiversity collected using relatively rapid sampling schemes.

A METHOD OF ESTIMATING YIELD FOR LARGE-SCALE FIELD RESEARCH PROJECTS

The Innovative Acres field-scale project was designed to compare water-efficient farming systems with the more commonly used crop-fallow farming system in Saskatchewan. This project spanned the period between 1982 and 1987, and tested 40 locations each year. The present study was undertaken at two of these locations, to compare the sampling methodology used by the Innovative Acres (IA) project with a more intensive sampling scheme, and thereby assess the relative validity of productivity estimates developed from the IA sampling method. At both locations, grain yield estimates for the field based upon twelve IA benchmark sites were statistically similar (P &gt; 0.05) to yield estimates from the more intensive sampling scheme (59 samples). Yield estimates from the IA transect more closely approximated the farmers' estimates of grain yield at both locations. Weighted grain yields, based on the distribution of topography along the transects, gave no better estimate of yield than did grouped mean data at both locations. The IA sampling procedure estimated to within 10% of the true mean grain yield, at the 90% probability level. It is concluded that this level of precision allows accurate comparisons to be made between two cropping systems. Key words: Field-scale research, transects, topography