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Sample records for macroinvertebrate sampling methods

  1. The Value of the Freshwater Snail Dip Scoop Sampling Method in Macroinvertebrates Bioassessment of Sugar Mill Wastewater Pollution in Mbandjock, Cameroon

    Directory of Open Access Journals (Sweden)

    Emmanuel Noumi

    2008-03-01

    Full Text Available Macroinvertebrates identification and enumeration may be used as a simple and affordable alternative to chemical analysis in water pollution monitoring. However, the ecological responses of various taxa to pollution are poorly known in resources-limited tropical countries. While freshwater macroinvertebrates have been used in the assessment of water quality in Europe and the Americas, investigations in Africa have mainly focused on snail hosts of human parasites. There is a need for sampling methods that can be used to assess both snails and other macroinvertebrates. The present study was designed to evaluate the usefulness of the freshwater snail dip scoop method in the study of macroinvertebrates for the assessment of the SOSUCAM sugar mill effluents pollution. Standard snail dip scoop samples were collected upstream and downstream of the factory effluent inputs, on the Mokona and Mengoala rivers. The analysis of the macroinvertebrate communities revealed the absence of Ephemeroptera and Trichoptera, and the thriving of Syrphidae in the sections of the rivers under high effluent load. The Shannon and Weaver diversity index was lower in these areas. The dip scoop sampling protocol was found to be a useful method for macroinvertebrates collection. Hence, this method is recommended as a simple, cost-effective and efficient tool for the bio-assessment of freshwater pollution in developing countries with limited research resources.

  2. Macroinvertebrate and algal community sample collection methods and data collected at selected sites in the Eagle River watershed, Colorado, 2000-07

    Science.gov (United States)

    Zuellig, Robert E.; Bruce, James F.

    2010-01-01

    State and local agencies are concerned about the effects of increasing urban development and human population growth on water quality and the biological condition of regional streams in the Eagle River watershed. In response to these needs, the U.S. Geological Survey initiated a study in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, Colorado Springs Utilities, Denver Water, and the U.S. Department of Agriculture Forest Service. As part of this study, previously collected macroinvertebrate and algal data from the Eagle River watershed were compiled. This report includes macroinvertebrate data collected by the U.S. Geological Survey and(or) the U.S. Department of Agriculture Forest Service from 73 sites from 2000 to 2007 and algal data collected from up to 26 sites between 2000 and 2001 in the Eagle River watershed. Additionally, a brief description of the sample collection methods and data processing procedures are presented.

  3. Evaluation of alternative macroinvertebrate sampling techniques for use in a new tropical freshwater bioassessment scheme

    OpenAIRE

    Isabel Eleanor Moore; Kevin Joseph Murphy

    2015-01-01

    Aim: The study aimed to determine the effectiveness of benthic macroinvertebrate dredge net sampling procedures as an alternative method to kick net sampling in tropical freshwater systems, specifically as an evaluation of sampling methods used in the Zambian Invertebrate Scoring System (ZISS) river bioassessment scheme. Tropical freshwater ecosystems are sometimes dangerous or inaccessible to sampling teams using traditional kick-sampling methods, so identifying an alternative procedure that...

  4. Evaluation of alternative macroinvertebrate sampling techniques for use in a new tropical freshwater bioassessment scheme

    Directory of Open Access Journals (Sweden)

    Isabel Eleanor Moore

    2015-06-01

    Full Text Available Aim: The study aimed to determine the effectiveness of benthic macroinvertebrate dredge net sampling procedures as an alternative method to kick net sampling in tropical freshwater systems, specifically as an evaluation of sampling methods used in the Zambian Invertebrate Scoring System (ZISS river bioassessment scheme. Tropical freshwater ecosystems are sometimes dangerous or inaccessible to sampling teams using traditional kick-sampling methods, so identifying an alternative procedure that produces similar results is necessary in order to collect data from a wide variety of habitats.MethodsBoth kick and dredge nets were used to collect macroinvertebrate samples at 16 riverine sites in Zambia, ranging from backwaters and floodplain lagoons to fast flowing streams and rivers. The data were used to calculate ZISS, diversity (S: number of taxa present, and Average Score Per Taxon (ASPT scores per site, using the two sampling methods to compare their sampling effectiveness. Environmental parameters, namely pH, conductivity, underwater photosynthetically active radiation (PAR, temperature, alkalinity, flow, and altitude, were also recorded and used in statistical analysis. Invertebrate communities present at the sample sites were determined using multivariate procedures.ResultsAnalysis of the invertebrate community and environmental data suggested that the testing exercise was undertaken in four distinct macroinvertebrate community types, supporting at least two quite different macroinvertebrate assemblages, and showing significant differences in habitat conditions. Significant correlations were found for all three bioassessment score variables between results acquired using the two methods, with dredge-sampling normally producing lower scores than did the kick net procedures. Linear regression models were produced in order to correct each biological variable score collected by a dredge net to a score similar to that of one collected by kick net

  5. Marine sediment sample pre-processing for macroinvertebrates metabarcoding: mechanical enrichment and homogenization

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    Eva Aylagas

    2016-10-01

    Full Text Available Metabarcoding is an accurate and cost-effective technique that allows for simultaneous taxonomic identification of multiple environmental samples. Application of this technique to marine benthic macroinvertebrate biodiversity assessment for biomonitoring purposes requires standardization of laboratory and data analysis procedures. In this context, protocols for creation and sequencing of amplicon libraries and their related bioinformatics analysis have been recently published. However, a standardized protocol describing all previous steps (i.e. processing and manipulation of environmental samples for macroinvertebrate community characterization is lacking. Here, we provide detailed procedures for benthic environmental sample collection, processing, enrichment for macroinvertebrates, homogenization, and subsequent DNA extraction for metabarcoding analysis. Since this is the first protocol of this kind, it should be of use to any researcher in this field, having the potential for improvement.

  6. Results of Macroinvertebrate Sampling Conducted at 33 SRS Stream Locations, July--August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1994-12-01

    In order to assess the health of the macroinvertebrate communities of SRS streams, the macroinvertebrate communities at 30 stream locations on SRS were sampled during the summer of 1993, using Hester-Dendy multiplate samplers. In addition, three off-site locations in the Upper Three Runs drainage were sampled in order to assess the potential for impact from off-site activities. In interpreting the data, it is important to recognize that these data were from a single set of collections. Macroinvertebrate communities often undergo considerable temporal variation, and are also greatly influenced by such factors as water depth, water velocity, and available habitat. These stations were selected with the intent of developing an on-going sampling program at a smaller number of stations, with the selection of the stations to be based largely upon the results of this preliminary sampling program. When stations within a given stream showed similar results, fewer stations would be sampled in the future. Similarly, if a stream appeared to be perturbed, additional stations or chemical analyses might be added so that the source of the perturbation could be identified. In general, unperturbed streams will contain more taxa than perturbed streams, and the distribution of taxa among orders or families will differ. Some groups of macroinvertebrates, such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), which are collectively called EPT taxa, are considered to be relatively sensitive to most kinds of stream perturbation; therefore a reduced number of EPT taxa generally indicates that the stream has been subject to chemical or physical stressors. In coastal plain streams, EPT taxa are generally less dominant than in streams with rocky substrates, while Chironomidae (midges) are more abundant. (Abstract Truncated)

  7. Long Term Resource Monitoring Program Annual Status Report, 1999: Macroinvertebrate Sampling in Six Reaches of the Upper Mississippi River System

    National Research Council Canada - National Science Library

    Sauer, Jennifer

    2000-01-01

    In 1992, macroinvertebrate sampling was initiated in Pools 4, 8, 13, 26, and the Open River reach of the Mississippi River, and La Orange Pool of the Illinois River as part of the Long Term Resource Monitoring Program...

  8. Comparison of two methods for estimating the abundance, diversity and habitat preference of fluvial macroinvertebrates in contrasting habitats

    NARCIS (Netherlands)

    Alonso, A.; Camargo, J.A.

    2010-01-01

    In this research we evaluate the effects of the method used for estimating the potential surface available for benthic macroinvertebrates in macrophyte and unvegetated habitats on several metrics and habitat preference of aquatic macroinvertebrates in the upper catchment of the Henares River

  9. Evaluating ethanol-based sample preservation to facilitate use of DNA barcoding in routine freshwater biomonitoring programs using benthic macroinvertebrates.

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    Eric D Stein

    Full Text Available Molecular methods, such as DNA barcoding, have the potential to enhance biomonitoring programs worldwide. Altering routinely used sample preservation methods to protect DNA from degradation may pose a potential impediment to application of DNA barcoding and metagenomics for biomonitoring using benthic macroinvertebrates. Using higher volumes or concentrations of ethanol, requirements for shorter holding times, or the need to include additional filtering may increase cost and logistical constraints to existing biomonitoring programs. To address this issue we evaluated the efficacy of various ethanol-based sample preservation methods at maintaining DNA integrity. We evaluated a series of methods that were minimally modified from typical field protocols in order to identify an approach that can be readily incorporated into existing monitoring programs. Benthic macroinvertebrates were collected from a minimally disturbed stream in southern California, USA and subjected to one of six preservation treatments. Ten individuals from five taxa were selected from each treatment and processed to produce DNA barcodes from the mitochondrial gene cytochrome c oxidase I (COI. On average, we obtained successful COI sequences (i.e. either full or partial barcodes for between 93-99% of all specimens across all six treatments. As long as samples were initially preserved in 95% ethanol, successful sequencing of COI barcodes was not affected by a low dilution ratio of 2∶1, transfer to 70% ethanol, presence of abundant organic matter, or holding times of up to six months. Barcoding success varied by taxa, with Leptohyphidae (Ephemeroptera producing the lowest barcode success rate, most likely due to poor PCR primer efficiency. Differential barcoding success rates have the potential to introduce spurious results. However, routine preservation methods can largely be used without adverse effects on DNA integrity.

  10. Sampling methods

    International Nuclear Information System (INIS)

    Loughran, R.J.; Wallbrink, P.J.; Walling, D.E.; Appleby, P.G.

    2002-01-01

    Methods for the collection of soil samples to determine levels of 137 Cs and other fallout radionuclides, such as excess 210 Pb and 7 Be, will depend on the purposes (aims) of the project, site and soil characteristics, analytical capacity, the total number of samples that can be analysed and the sample mass required. The latter two will depend partly on detector type and capabilities. A variety of field methods have been developed for different field conditions and circumstances over the past twenty years, many of them inherited or adapted from soil science and sedimentology. The use of them inherited or adapted from soil science and sedimentology. The use of 137 Cs in erosion studies has been widely developed, while the application of fallout 210 Pb and 7 Be is still developing. Although it is possible to measure these nuclides simultaneously, it is common for experiments to designed around the use of 137 Cs along. Caesium studies typically involve comparison of the inventories found at eroded or sedimentation sites with that of a 'reference' site. An accurate characterization of the depth distribution of these fallout nuclides is often required in order to apply and/or calibrate the conversion models. However, depending on the tracer involved, the depth distribution, and thus the sampling resolution required to define it, differs. For example, a depth resolution of 1 cm is often adequate when using 137 Cs. However, fallout 210 Pb and 7 Be commonly has very strong surface maxima that decrease exponentially with depth, and fine depth increments are required at or close to the soil surface. Consequently, different depth incremental sampling methods are required when using different fallout radionuclides. Geomorphic investigations also frequently require determination of the depth-distribution of fallout nuclides on slopes and depositional sites as well as their total inventories

  11. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  12. L-Lake macroinvertebrate community

    International Nuclear Information System (INIS)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake's macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors

  13. Rapid Bioassessment Methods for Assessing Stream Macroinvertebrate Community on the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1999-11-22

    Macroinvertebrate sampling was performed at 16 locations in the Savannah River Site (SRS) streams using Hester-Dendy multiplate samplers and EPA Rapid Bioassessment Protocols (RBP). Some of the sampling locations were unimpacted, while other locations had been subject to various forms of perturbation by SRS activities. In general, the data from the Hester-Dendy multiplate samplers were more sensitive at detecting impacts than were the RBP data. We developed a Biotic Index for the Hester-Dendy data which incorporated eight community structure, function, and balance parameters. when tested using a data set that was unrelated to the data set that was used in developing the Biotic Index, the index was very successful at detecting impact.

  14. Rapid Bioassessment Methods for Assessing Stream Macroinvertebrate Community on the Savannah River Site

    International Nuclear Information System (INIS)

    Specht, W.L.

    1999-01-01

    Macroinvertebrate sampling was performed at 16 locations in the Savannah River Site (SRS) streams using Hester-Dendy multiplate samplers and EPA Rapid Bioassessment Protocols (RBP). Some of the sampling locations were unimpacted, while other locations had been subject to various forms of perturbation by SRS activities. In general, the data from the Hester-Dendy multiplate samplers were more sensitive at detecting impacts than were the RBP data. We developed a Biotic Index for the Hester-Dendy data which incorporated eight community structure, function, and balance parameters. when tested using a data set that was unrelated to the data set that was used in developing the Biotic Index, the index was very successful at detecting impact

  15. Macroinvertebrate diversity in the karst Jadro River (Croatia

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    Rađa Biljana

    2008-01-01

    Full Text Available This paper presents the results of 10 years of investigation of the aquatic macroinvertebrate fauna along the karst Jadro River. The Jadro is a typical karst river. Benthic macroinvertebrates were collected along the river at 15 sites by standard methods of sampling, in addition to which several physicochemical parameters were also determined. Based on qualitative and quantitative composition of the macroinvertebrate fauna, correspondence analysis divided the river course into three sections: upstream, midcourse, and downstream. Forty-three taxa were recorded. Results of saprobiological analysis based on macrozoobenthos indicate that water of the Jadro River belongs to quality classes I and II.

  16. Development of a local-scale urban stream assessment method using benthic macroinvertebrates: An example from the Santa Clara Basin, California

    Science.gov (United States)

    Carter, J.L.; Purcell, A.H.; Fend, S.V.; Resh, V.H.

    2009-01-01

    Research that explores the biological response to urbanization on a site-specific scale is necessary for management of urban basins. Recent studies have proposed a method to characterize the biological response of benthic macroinvertebrates along an urban gradient for several climatic regions in the USA. Our study demonstrates how this general framework can be refined and applied on a smaller scale to an urbanized basin, the Santa Clara Basin (surrounding San Jose, California, USA). Eighty-four sampling sites on 14 streams in the Santa Clara Basin were used for assessing local stream conditions. First, an urban index composed of human population density, road density, and urban land cover was used to determine the extent of urbanization upstream from each sampling site. Second, a multimetric biological index was developed to characterize the response of macroinvertebrate assemblages along the urban gradient. The resulting biological index included metrics from 3 ecological categories: taxonomic composition ( Ephemeroptera, Plecoptera, and Trichoptera), functional feeding group (shredder richness), and habit ( clingers). The 90th-quantile regression line was used to define the best available biological conditions along the urban gradient, which we define as the predicted biological potential. This descriptor was then used to determine the relative condition of sites throughout the basin. Hierarchical partitioning of variance revealed that several site-specific variables (dissolved O2 and temperature) were significantly related to a site's deviation from its predicted biological potential. Spatial analysis of each site's deviation from its biological potential indicated geographic heterogeneity in the distribution of impaired sites. The presence and operation of local dams optimize water use, but modify natural flow regimes, which in turn influence stream habitat, dissolved O2, and temperature. Current dissolved O2 and temperature regimes deviate from natural

  17. Relationships of sedimentation and benthic macroinvertebrate assemblages in headwater streams using systematic longitudinal sampling at the reach scale.

    Science.gov (United States)

    Longing, S D; Voshell, J R; Dolloff, C A; Roghair, C N

    2010-02-01

    Investigating relationships of benthic invertebrates and sedimentation is challenging because fine sediments act as both natural habitat and potential pollutant at excessive levels. Determining benthic invertebrate sensitivity to sedimentation in forested headwater streams comprised of extreme spatial heterogeneity is even more challenging, especially when associated with a background of historical and intense watershed disturbances that contributed unknown amounts of fine sediments to stream channels. This scenario exists in the Chattahoochee National Forest where such historical timber harvests and contemporary land-uses associated with recreation have potentially affected the biological integrity of headwater streams. In this study, we investigated relationships of sedimentation and the macroinvertebrate assemblages among 14 headwater streams in the forest by assigning 30, 100-m reaches to low, medium, or high sedimentation categories. Only one of 17 assemblage metrics (percent clingers) varied significantly across these categories. This finding has important implications for biological assessments by showing streams impaired physically by sedimentation may not be impaired biologically, at least using traditional approaches. A subsequent multivariate cluster analysis and indicator species analysis were used to further investigate biological patterns independent of sedimentation categories. Evaluating the distribution of sedimentation categories among biological reach clusters showed both within-stream variability in reach-scale sedimentation and sedimentation categories generally variable within clusters, reflecting the overall physical heterogeneity of these headwater environments. Furthermore, relationships of individual sedimentation variables and metrics across the biological cluster groups were weak, suggesting these measures of sedimentation are poor predictors of macroinvertebrate assemblage structure when using a systematic longitudinal sampling design

  18. Effects of Student-Induced Trampling on Aquatic Macroinvertebrates in Agricultural Headwater Streams

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    Jon P. Bossley

    2018-01-01

    Full Text Available Outdoor education (OE stream classes provide students with an opportunity to gain hands-on experience with sampling methods for evaluating stream water quality. Trampling by students as a result of stream classes may disrupt the substrate and negatively impact aquatic macroinvertebrates. The impact of student-induced trampling in headwaters as a result of stream classes on aquatic macroinvertebrates has not been evaluated. Our aim was to document the short-term macroinvertebrate responses to an experimental disturbance that simulated the impacts of trampling by students in riffles within small headwater streams. We measured hydrologic variables, visually estimated substrate composition and sampled aquatic macroinvertebrates within control and experimental riffles in three agricultural headwater streams in central Ohio one day prior to experimental disturbance, immediately after disturbance and one day after disturbance. Hydrologic variables and substrate type did not differ daily or between riffle types. Macroinvertebrate abundance, percentage of Ephemeroptera Plecoptera Trichoptera and percentage of Leuctridae increased after experimental disturbance, while diversity, evenness, percentage of clingers and non-metric multidimensional scaling (NMS axis 1 site scores declined after disturbance. Macroinvertebrate diversity, percent clingers and NMS axis 1 site scores were lower in experimental riffles than control riffles. None of the macroinvertebrate response variables exhibited a significant interaction effect of day × riffle type that is indicative of an effect of the experimental disturbance. Our results suggest the one-time use of an undisturbed riffle within an agricultural headwater stream for an OE stream class is not likely to impact aquatic macroinvertebrates.

  19. Fish stomach contents in benthic macroinvertebrate assemblage assessments

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    TH. Tupinambás

    Full Text Available The choice of sampling gears to assess benthic macroinvertebrate communities depends on environmental characteristics, study objectives, and cost effectiveness. Because of the high foraging capacity and diverse habitats and behaviors of benthophagous fishes, their stomach contents may offer a useful sampling tool in studies of benthic macroinvertebrates, especially in large, deep, fast rivers that are difficult to sample with traditional sediment sampling gear. Our objective was to compare the benthic macroinvertebrate communities sampled from sediments with those sampled from fish stomachs. We collected benthic macroinvertebrates and fish from three different habitat types (backwater, beach, riffle in the wet season, drying season, and dry season along a single reach of the Grande River (Paraná River Basin, southeast Brazil. We sampled sediments through use of a Petersen dredge (total of 216 grabs and used gill nets to sample fish (total of 36 samples. We analyzed the stomach contents of three commonly occurring benthophagous fish species (Eigenmannia virescens, Iheringichthys labrosus, Leporinus amblyrhynchus. Chironomids dominated in both sampling methods. Macroinvertebrate taxonomic composition and abundances from fish stomachs differed from those from sediment samples, but less so from riffles than from backwater and beach habitats. Macroinvertebrate taxa from E. virescens stomachs were more strongly correlated with sediment samples from all three habitats than were those from the other two species. The species accumulation curves and higher mean dispersion values, compared with with sediment samples suggest that E. virescens is more efficient than sediment samples and the other fish studied at collecting benthic taxa. We conclude that by analyzing the stomach contents of benthophagous fishes it is possible to assess important characteristics of benthic communities (dispersion, taxonomic composition and diversity. This is especially true

  20. Environmental drivers of the benthic macroinvertebrates community in a hypersaline estuary (Northeastern Brazil

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    Carlinda Railly Ferreira Medeiros

    Full Text Available Abstract Introduction The estuarine community of benthic macroinvertebrates spatially varies in response to changes in environmental variables in these ecosystems. Understanding this variability helps our understanding the mechanisms structuring these communities. Aim Assess the structural aspects of the benthic macroinvertebrate community in a hypersaline estuary, and to relate to environmental variables that influence the community structure along the estuary. Methods The study was conducted at Tubarão river estuary in May 2015. We sampled two estuarine areas (upper and lower, and in each zone were sampled six points composed of two replicas, one sampled in sandy bottom and the other in muddy bottom. Samples of benthic macroinvertebrates and estuarine environmental variables were collected. Environmental drivers of the benthic macroinvertebrate community were determined by Distance-based Linear Models analysis. The contribution of individual species to the dissimilarity between the areas and substrate types were determined by analysis of the percentage of similarity. Results The composition of benthic macroinvertebrate community differed between the upper and lower areas, although it was similar between the muddy and sandy bottoms. The variation in the benthic community between areas was mainly related to the influence of salinity in the upper area. In the lower area, the variation of the macroinvertebrates was related to salinity, associated with other variables in the sandy (temperature, turbidity and dissolved oxygen and muddy (temperature, total dissolved solids and dissolved oxygen substrates. Taxa which contributed most to the dissimilarity between the upper and lower areas were Nereididae (17.89%, Anomalocardia brasiliana (15% and Cirratulidae (10.43%. Conclusions Salinity was the main driver of the structural aspects of the benthic macroinvertebrate community in the upper area of the estuary, although in the lower area a set of

  1. Sampling system and method

    Science.gov (United States)

    Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

    2013-04-16

    The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.

  2. The Colonization of Newly Built Fishponds by the Macroinvertebrate Assemblages

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    Pavla Řezníčková

    2016-01-01

    Full Text Available The succession of standing waters by aquatic macroinvertebrates is a present and insufficiently surveyed topic. This study is addressed to the issue of colonisation of newly created small standing waters. Two fishponds situated in the north of Moravia (Czech Republic were studied. The aim of this study was to determine the character and colonisation rate of these ponds by macroinvertebrates, to evaluate the abundance, taxonomic composition and changes in composition of freshwater assemblages as a result of the fish stock influence. Basic abiotic parameters were also measured within the sampling occasions (e.g. water temperature, dissolved oxygen, conductivity, pH, total nitrogen and phosphorus concentrations. Samples of aquatic macroinvertebrates were taken monthly during the years 2012 and 2013, by kick sampling method using the hand net. The character of sampled fishponds was very similar, environmental parameters (e.g. area, substrate, depth etc. were comparable. The colonisation of both fishponds was very fast. The pioneer colonists were mainly insect larvae (e.g. chironomids. Very low numbers of macroinvertebrates as a result of fish stock influence were recorded on both sites during the observation with the highest abundances in summer season.

  3. Independent random sampling methods

    CERN Document Server

    Martino, Luca; Míguez, Joaquín

    2018-01-01

    This book systematically addresses the design and analysis of efficient techniques for independent random sampling. Both general-purpose approaches, which can be used to generate samples from arbitrary probability distributions, and tailored techniques, designed to efficiently address common real-world practical problems, are introduced and discussed in detail. In turn, the monograph presents fundamental results and methodologies in the field, elaborating and developing them into the latest techniques. The theory and methods are illustrated with a varied collection of examples, which are discussed in detail in the text and supplemented with ready-to-run computer code. The main problem addressed in the book is how to generate independent random samples from an arbitrary probability distribution with the weakest possible constraints or assumptions in a form suitable for practical implementation. The authors review the fundamental results and methods in the field, address the latest methods, and emphasize the li...

  4. Evaluating Ethanol-based Sample Preservation to Facilitate Use of DNA Barcoding in Routine Freshwater Biomonitoring Programs Using Benthic Macroinvertebrates

    Science.gov (United States)

    Molecular methods, such as DNA barcoding, have the potential in enhance biomonitoring programs worldwide. Altering routinely used sample preservation methods to protect DNA from degradation may pose a potential impediment to application of DNA barcoding and metagenomics for biom...

  5. Radioactive air sampling methods

    CERN Document Server

    Maiello, Mark L

    2010-01-01

    Although the field of radioactive air sampling has matured and evolved over decades, it has lacked a single resource that assimilates technical and background information on its many facets. Edited by experts and with contributions from top practitioners and researchers, Radioactive Air Sampling Methods provides authoritative guidance on measuring airborne radioactivity from industrial, research, and nuclear power operations, as well as naturally occuring radioactivity in the environment. Designed for industrial hygienists, air quality experts, and heath physicists, the book delves into the applied research advancing and transforming practice with improvements to measurement equipment, human dose modeling of inhaled radioactivity, and radiation safety regulations. To present a wide picture of the field, it covers the international and national standards that guide the quality of air sampling measurements and equipment. It discusses emergency response issues, including radioactive fallout and the assets used ...

  6. Comparability among four invertebrate sampling methods and two multimetric indexes, Fountain Creek Basin, Colorado, 2010–2012

    Science.gov (United States)

    Bruce, James F.; Roberts, James J.; Zuellig, Robert E.

    2018-05-24

    The U.S. Geological Survey (USGS), in cooperation with Colorado Springs City Engineering and Colorado Springs Utilities, analyzed previously collected invertebrate data to determine the comparability among four sampling methods and two versions (2010 and 2017) of the Colorado Benthic Macroinvertebrate Multimetric Index (MMI). For this study, annual macroinvertebrate samples were collected concurrently (in space and time) at 15 USGS surface-water gaging stations in the Fountain Creek Basin from 2010 to 2012 using four sampling methods. The USGS monitoring project in the basin uses two of the methods and the Colorado Department of Public Health and Environment recommends the other two. These methods belong to two distinct sample types, one that targets single habitats and one that targets multiple habitats. The study results indicate that there are significant differences in MMI values obtained from the single-habitat and multihabitat sample types but methods from each program within each sample type produced comparable values. This study also determined that MMI values calculated by different versions of the Colorado Benthic Macroinvertebrate MMI are indistinguishable. This indicates that the Colorado Department of Public Health and Environment methods are comparable with the USGS monitoring project methods for single-habitat and multihabitat sample types. This report discusses the direct application of the study results to inform the revision of the existing USGS monitoring project in the Fountain Creek Basin.

  7. Short-term disturbance effects of outdoor education stream classes on aquatic macroinvertebrates

    Science.gov (United States)

    Outdoor education stream classes provide students with an opportunity to gain hands-on experience with sampling methods for evaluating stream water quality. Student trampling as a result of stream classes may disrupt the substrate and negatively impact aquatic macroinvertebrates. The impact of stude...

  8. A method of language sampling

    DEFF Research Database (Denmark)

    Rijkhoff, Jan; Bakker, Dik; Hengeveld, Kees

    1993-01-01

    In recent years more attention is paid to the quality of language samples in typological work. Without an adequate sampling strategy, samples may suffer from various kinds of bias. In this article we propose a sampling method in which the genetic criterion is taken as the most important: samples...... to determine how many languages from each phylum should be selected, given any required sample size....

  9. THE INFLUENCE OF POST-FLOTATION TAILINGS POND “WARTOWICE” (LOWER SILESIA ON THE BIODIVERSITY OF MACROINVERTEBRATES

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    Justyna Rybak

    2013-10-01

    Full Text Available In this paper the biodiversity studies on macroinvertebrates were conducted in the area post-flotation tailings pond “Wartowice”, which poses a serious threat to the environment. The analysis of the biodiversity was done with two methods: the use of biodiversity indices along with taxonomic identification to family level and with the application of morphospecies method. Both were assessed concerning their usefulness. Macrofauna was sampled in a five sites characterized by different level of pollution. We found the dependence of macroinvertebrates structure on habitat type. Both methods, although not very accurate, were found suitable for the assessment of such disturbance type.

  10. A method of language sampling

    DEFF Research Database (Denmark)

    Rijkhoff, Jan; Bakker, Dik; Hengeveld, Kees

    1993-01-01

    In recent years more attention is paid to the quality of language samples in typological work. Without an adequate sampling strategy, samples may suffer from various kinds of bias. In this article we propose a sampling method in which the genetic criterion is taken as the most important: samples...... created with this method will reflect optimally the diversity of the languages of the world. On the basis of the internal structure of each genetic language tree a measure is computed that reflects the linguistic diversity in the language families represented by these trees. This measure is used...... to determine how many languages from each phylum should be selected, given any required sample size....

  11. Trophic structure of macroinvertebrates in tropical pasture streams

    Directory of Open Access Journals (Sweden)

    Bruna Neves da Silveira-Manzotti

    Full Text Available Abstract: Aim The aim of this study was to describe the diet of stream macroinvertebrates and to determine their trophic groups. Methods Invertebrates were sampled with D nets in three pasture streams. They were identified to genus level and submitted to gut content analysis, except for fluid feeders such as hemipterans, to which diet data was obtained from the literature. Trophic groups were determined based on a similarity analysis using the Bray-Curtis similarity coefficient. Results Five trophic groups were defined: fine-detritivores (feed mostly on fine particulate organic matter - FPOM, coarse-detritivores/herbivores (feed mostly on coarse particulate organic matter - CPOM - and plant material, omnivores, specialist-predators (prey upon aquatic insects only, and generalist-predators. Ephemeroptera, Diptera (except Tanypodinae, Coleoptera, and Trichoptera (except Smicridea were detritivores. The caddis Macronema (Trichoptera fed exclusively on plant detritus and Tanypodinae and Smicridea were classified as omnivores. The odonate families Calopterygidae and Gomphidae were classified as specialist-predators, while Macrobrachium (Decapoda, Belostoma, and Limnocoris (Hemiptera were generalist-predators. Conclusions The great quantity and frequency of occurrence of FPOM consumed by most taxa highlight the importance of this food resource for macroinvertebrate communities from tropical streams. Furthermore, observed variations on trophic group assignment for some taxa indicate the generalist and opportunistic nature of these aquatic invertebrates. Such findings reinforce the importance of conducting gut content analysis on macroinvertebrates to understand their role in the structure and functioning of tropical streams.

  12. Colonization by benthic macroinvertebrates in two artificial substrate types of a Riparian Forest

    Directory of Open Access Journals (Sweden)

    Lívia Borges dos Santos

    Full Text Available Abstract: Aim To analyze the efficiency of organic and inorganic substrates in samples of benthic macroinvertebrates of riparian forests from the Cerrado. Specific objectives (i characterize the ecological succession and taxonomic richness of benthic macroinvertebrates in stream affluent of a riparian forest; (ii analyze the influence of seasonality on the colonization of macroinvertebrates; and (iii determine the effect of the types of artificial substrates on the richness, composition and abundance of the benthic community. Methods Sampling was carried out in the rainy and dry seasons, and we installed in the watercourse two types of substrates: organic (leaf packs and inorganic (bricks, organized in pairs. Six samples per season were done to verify colonization, succession, richness and abundance of benthic community. The substrates were carefully sorted and the organisms were identified to the lowest possible taxonomic level. Results The ecological succession was clearly observed, with the initial occurrence of Chironomidae and Baetidae (considered early colonizers, and a late occurrence of organisms such as Helotrephidae and Trichoptera (considered late colonizers. No significant difference was found in the richness and abundance among the studied seasons (rainy and dry, but the organic substrate was significantly higher than the inorganic substrate for these parameters. Conclusion Organic artificial substrates are more efficient in characterizing the community of benthic macroinvertebrates in the study area, because they are more similar to the conditions of the substrate found naturally in the environment.

  13. Metal contamination in benthic macroinvertebrates in a sub-basin in the southeast of Brazil

    Directory of Open Access Journals (Sweden)

    WAC Chiba

    Full Text Available Benthic macroinvertebrates have many useful properties that make possible the use of these organisms as sentinel in biomonitoring programmes in freshwater. Combined with the characteristics of the water and sediment, benthic macroinvertebrates are potential indicators of environmental quality. Thus, the spatial occurrence of potentially toxic metals (Al, Zn, Cr, Co, Cu, Fe, Mn and Ni in the water, sediment and benthic macroinvertebrates samples were investigated in a sub-basin in the southeast of Brazil in the city of São Carlos, São Paulo state, with the aim of verifying the metals and environment interaction with benthic communities regarding bioaccumulation. Hypothetically, there can be contamination by metals in the aquatic environment in the city due to lack of industrial effluent treatment. All samples were analysed by the USEPA adapted method and processed in an atomic absorption spectrophotometer. The sub-basin studied is contaminated by toxic metals in superficial water, sediment and benthic macroinvertebrates. The Bioaccumulation Factor showed a tendency for metal bioaccumulation by the benthic organisms for almost all the metal species. The results show a potential human and ecosystem health risk, contributing to metal contamination studies in aquatic environments in urban areas.

  14. Aquatic macroinvertebrates associated with roots of Eichhornia azuera (Swarts Kunth (Pontederiaceae in an oxbow lake in Pantanal, MS

    Directory of Open Access Journals (Sweden)

    Hugo Henrique L. Saulino

    2014-09-01

    Full Text Available Macrophytes play an important role in the community structure of aquatic systems. In this study, we examined the macroinvertebrate communities within 20 Eichhornia azurea roots in an oxbow lake in Pantanal (MS during dry season. Species abundance and richness were compared via linear regression, and the mean relative proportion of macroinvertebrates among root samples was determined. Macroinvertebrates were identified to the lowest practical taxonomic level, and root volume was measured using the volume displacement method. We identified 371 specimens, belonging to 31 families and 21 taxonomic groups. Chironomus sp. (Chironomidae, Slavinia sp. and Dero sp. (Naididae, all detritivores, were most the represented taxon. Regression analysis indicated a positive correlation between root volume and the abundance and richness of the macroinvertebrate community. Analysis of variance showed no statistically significant differences between species abundance and richness among different E. azuera root volumes, however we did observe a trend toward a positive correlation of both variables with increasing root volume. We suspect that greater root volumes should increase microhabitat availability, which could explain this observed trend. Our results indicate that E. azurea roots may play an important ecologic role (e.g., by providing shelter, food stock in lake macroinvertebrate communities.

  15. SWOT ANALYSIS ON SAMPLING METHOD

    Directory of Open Access Journals (Sweden)

    CHIS ANCA OANA

    2014-07-01

    Full Text Available Audit sampling involves the application of audit procedures to less than 100% of items within an account balance or class of transactions. Our article aims to study audit sampling in audit of financial statements. As an audit technique largely used, in both its statistical and nonstatistical form, the method is very important for auditors. It should be applied correctly for a fair view of financial statements, to satisfy the needs of all financial users. In order to be applied correctly the method must be understood by all its users and mainly by auditors. Otherwise the risk of not applying it correctly would cause loose of reputation and discredit, litigations and even prison. Since there is not a unitary practice and methodology for applying the technique, the risk of incorrectly applying it is pretty high. The SWOT analysis is a technique used that shows the advantages, disadvantages, threats and opportunities. We applied SWOT analysis in studying the sampling method, from the perspective of three players: the audit company, the audited entity and users of financial statements. The study shows that by applying the sampling method the audit company and the audited entity both save time, effort and money. The disadvantages of the method are difficulty in applying and understanding its insight. Being largely used as an audit method and being a factor of a correct audit opinion, the sampling method’s advantages, disadvantages, threats and opportunities must be understood by auditors.

  16. Distance sampling methods and applications

    CERN Document Server

    Buckland, S T; Marques, T A; Oedekoven, C S

    2015-01-01

    In this book, the authors cover the basic methods and advances within distance sampling that are most valuable to practitioners and in ecology more broadly. This is the fourth book dedicated to distance sampling. In the decade since the last book published, there have been a number of new developments. The intervening years have also shown which advances are of most use. This self-contained book covers topics from the previous publications, while also including recent developments in method, software and application. Distance sampling refers to a suite of methods, including line and point transect sampling, in which animal density or abundance is estimated from a sample of distances to detected individuals. The book illustrates these methods through case studies; data sets and computer code are supplied to readers through the book’s accompanying website.  Some of the case studies use the software Distance, while others use R code. The book is in three parts.  The first part addresses basic methods, the ...

  17. Are macroinvertebrates in high altitude streams affected by oxygen deficiency?

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Rostgaard, S.; Vásconez, J. J.

    2003-01-01

    1. The solubility of oxygen in water increases with decreasing temperature. This has led to a general perception of cold, high mountain streams as more oxygen rich than warmer lowland streams, and that macroinvertebrates inhabiting high altitude streams have had no need to adapt to critical oxygen...... conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes. 2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small...... the mean weight-specific respiratory rate of macroinvertebrates declined by only 50%, from 400 to 3800 m. We suggest that this disproportionately large gap between availability and demand of oxygen at high altitudes may imply a potential oxygen deficiency for the fauna, and we discuss how oxygen deficiency...

  18. An improved selective sampling method

    International Nuclear Information System (INIS)

    Miyahara, Hiroshi; Iida, Nobuyuki; Watanabe, Tamaki

    1986-01-01

    The coincidence methods which are currently used for the accurate activity standardisation of radio-nuclides, require dead time and resolving time corrections which tend to become increasingly uncertain as countrates exceed about 10 K. To reduce the dependence on such corrections, Muller, in 1981, proposed the selective sampling method using a fast multichannel analyser (50 ns ch -1 ) for measuring the countrates. It is, in many ways, more convenient and possibly potentially more reliable to replace the MCA with scalers and a circuit is described employing five scalers; two of them serving to measure the background correction. Results of comparisons using our new method and the coincidence method for measuring the activity of 60 Co sources yielded agree-ment within statistical uncertainties. (author)

  19. Coupling methods for multistage sampling

    OpenAIRE

    Chauvet, Guillaume

    2015-01-01

    Multistage sampling is commonly used for household surveys when there exists no sampling frame, or when the population is scattered over a wide area. Multistage sampling usually introduces a complex dependence in the selection of the final units, which makes asymptotic results quite difficult to prove. In this work, we consider multistage sampling with simple random without replacement sampling at the first stage, and with an arbitrary sampling design for further stages. We consider coupling ...

  20. Stream Macroinvertebrate Occurrence along Gradients in Organic Pollution and Eutrophication

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Skriver, Jens; Larsen, Søren Erik

    2010-01-01

    We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part of the Da......We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part...

  1. Water quality in Danube Delta Lakes: An assessment using benthic macroinvertebrates community

    Directory of Open Access Journals (Sweden)

    IBRAM Orhan

    2016-12-01

    Full Text Available An assessment of the ecological status of selected lakes in the Danube Delta Biosphere Reserve was done based on temporal and spatial variation of macroinvertebrate communities during 2012 and 2013. Macroinvertebrate communities and measures of these communities were evaluated and a baseline characterization of assemblages was determined for the analyzed sites. Each year, three sampling campaigns, one for each ice-free season were organized for data collection. Macroinvertebrate samples have been collected in every lake from three different stations with the use of an Ekmann dredge. The highest taxa richness are recorded in Fortuna and Isac lakes in 2013. Total abundance followed a pattern similar to taxa number with Fortuna and Isac lakes having the highest yearly values (maximum number of individuals – 225 - per sample has been recorded in September 2013, in Isac Lake.Using saprobic index as an indicator of ecological status Isac lake was classifies as moderate and other three lakes, Merhei, Furtuna and Rosu as good ecological status. Lack of correlation between diversity indices and the saprobic values suggests that other assessment methods could be more effective and provide better information than saprobic index does at least for Danube Delta.

  2. Aquatic macroinvertebrates and water quality in Sandia Canyon

    International Nuclear Information System (INIS)

    Bennett, K.

    1994-05-01

    In 1990, field studies of water quality and stream macroinvertebrate communities were initiated in Sandia Canyon at Los Alamos National Laboratory. The studies were designed to establish baseline data and to determine the effects of routine discharges of industrial and sanitary waste. Water quality measurements were taken and aquatic macroinvertebrates sampled at three permanent stations within the canyon. Two of the three sample stations are located where the stream regularly receives industrial and sanitary waste effluents. These stations exhibited a low diversity of macroinvertebrates and slightly degraded water quality. The last sample station, located approximately 0.4 km (0.25 mi) downstream from the nearest wastewater outfall, appears to be in a zone of recovery where water quality parameters more closely resemble those found in natural streams in the Los Alamos area. A large increase in macroinvertebrate diversity was also observed at the third station. These results indicate that effluents discharged into Sandia Canyon have a marked effect on water quality and aquatic macroinvertebrate communities

  3. Towards Cost-efficient Sampling Methods

    OpenAIRE

    Peng, Luo; Yongli, Li; Chong, Wu

    2014-01-01

    The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper presents two new sampling methods based on the perspective that a small part of vertices with high node degree can possess the most structure information of a network. The two proposed sampling methods are efficient in sampling the nodes with high degree. The first new sampling method is improved on the basis of the stratified random sampling method and...

  4. Sample processing device and method

    DEFF Research Database (Denmark)

    2011-01-01

    A sample processing device is disclosed, which sample processing device comprises a first substrate and a second substrate, where the first substrate has a first surface comprising two area types, a first area type with a first contact angle with water and a second area type with a second contact...... angle with water, the first contact angle being smaller than the second contact angle. The first substrate defines an inlet system and a preparation system in areas of the first type which two areas are separated by a barrier system in an area of the second type. The inlet system is adapted to receive...

  5. The Effects of Exurbanization on Bird and Macroinvertebrate Communities in Deciduous Forests on the Cumberland Plateau, Tennessee

    Directory of Open Access Journals (Sweden)

    Jordan M. Casey

    2009-01-01

    Full Text Available To investigate the potential causes of changes to bird communities in exurban areas, we examined the relationship between bird and macroinvertebrate communities in exurbanized forest. We randomly located sampling points across a gradient of exurbanization. We used point counts to quantify bird communities and sweep netting, soil cores, pitfalls, and frass collectors to quantify macroinvertebrates. Bird communities had higher richness and abundance in exurban areas compared to undeveloped forests, and lost some species of conservation concern but gained others. The macroinvertebrate community was slightly more abundant in exurban areas, with a slight shift in taxonomic composition. The abundance of macroinvertebrates in soil cores (but not pitfalls predicted the abundance of ground-foraging birds. The abundance of macroinvertebrates in sweep nets was not associated with the abundance of aerial insectivore birds. Exurbanization therefore appears to change bird and macroinvertebrate communities, but to a lesser extent than agricultural forest fragmentation or intensive urbanization.

  6. The impact of episodic coal mine drainage pollution on benthic macroinvertebrates in streams in the Anthracite region of Pennsylvania

    International Nuclear Information System (INIS)

    MacCausland, A.; McTammany, M.E.

    2007-01-01

    Episodic coal mine drainage, caused by fluctuations in mine discharges relative to stream flow, has devastating effects on aquatic macroinvertebrate communities. Seven stream reaches in the Anthracite region of Pennsylvania were identified as chronically, episodically or not impaired by mine drainage, and sampled seasonally for 1 year to determine the effect of episodic mine drainage on macroinvertebrates. Specific conductance fluctuated seasonally in episodic sites; it was lower in winter when discharge increased and higher in summer when discharges decreased and mine drainage made up a larger proportion of stream flow. Although we hypothesized that episodic streams would have higher macroinvertebrate richness than chronic streams, comparisons showed no differences in richness between treatments. Episodic pollution may result from undersized or poorly maintained passive treatment systems; therefore, intensive macroinvertebrate monitoring may be needed to identify streams being affected by episodic mine drainage because macroinvertebrate richness may be sensitive to water quality fluctuations. - Episodic coal mine pollution decreases benthic macroinvertebrate richness and density

  7. Comparison of sampling methods for animal manure

    NARCIS (Netherlands)

    Derikx, P.J.L.; Ogink, N.W.M.; Hoeksma, P.

    1997-01-01

    Currently available and recently developed sampling methods for slurry and solid manure were tested for bias and reproducibility in the determination of total phosphorus and nitrogen content of samples. Sampling methods were based on techniques in which samples were taken either during loading from

  8. Standard methods for sampling and sample preparation for gamma spectroscopy

    International Nuclear Information System (INIS)

    Taskaeva, M.; Taskaev, E.; Nikolov, P.

    1993-01-01

    The strategy for sampling and sample preparation is outlined: necessary number of samples; analysis and treatment of the results received; quantity of the analysed material according to the radionuclide concentrations and analytical methods; the minimal quantity and kind of the data needed for making final conclusions and decisions on the base of the results received. This strategy was tested in gamma spectroscopic analysis of radionuclide contamination of the region of Eleshnitsa Uranium Mines. The water samples was taken and stored according to the ASTM D 3370-82. The general sampling procedures were in conformity with the recommendations of ISO 5667. The radionuclides was concentrated by coprecipitation with iron hydroxide and ion exchange. The sampling of soil samples complied with the rules of ASTM C 998, and their sample preparation - with ASTM C 999. After preparation the samples were sealed hermetically and measured. (author)

  9. Aquatic macroinvertebrates of the Jablanica river, Serbia

    Directory of Open Access Journals (Sweden)

    Stefanović Katarina S.

    2009-01-01

    Full Text Available Research on the community of aquatic macroinvertebrates was carried out during 2005 and 2006 at four sampling sites along the Jablanica River, a right-hand tributary of the Kolubara River. Fifty-seven taxa were recorded in the course of the investigation. The most diverse group was Ephemeroptera, followed by Trichoptera and Plecoptera. Members of the Rhitrogena semicolorata group were the most abundant. Our results could be the basis for evaluation of the influence of damming of the Jablanica River on the status of its water and can serve as a model for studying the influ­ence of hydromorphological degradation of aquatic ecosystems.

  10. Toward cost-efficient sampling methods

    Science.gov (United States)

    Luo, Peng; Li, Yongli; Wu, Chong; Zhang, Guijie

    2015-09-01

    The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper proposes two new sampling methods based on the idea that a small part of vertices with high node degree could possess the most structure information of a complex network. The two proposed sampling methods are efficient in sampling high degree nodes so that they would be useful even if the sampling rate is low, which means cost-efficient. The first new sampling method is developed on the basis of the widely used stratified random sampling (SRS) method and the second one improves the famous snowball sampling (SBS) method. In order to demonstrate the validity and accuracy of two new sampling methods, we compare them with the existing sampling methods in three commonly used simulation networks that are scale-free network, random network, small-world network, and also in two real networks. The experimental results illustrate that the two proposed sampling methods perform much better than the existing sampling methods in terms of achieving the true network structure characteristics reflected by clustering coefficient, Bonacich centrality and average path length, especially when the sampling rate is low.

  11. An improved sampling method of complex network

    Science.gov (United States)

    Gao, Qi; Ding, Xintong; Pan, Feng; Li, Weixing

    2014-12-01

    Sampling subnet is an important topic of complex network research. Sampling methods influence the structure and characteristics of subnet. Random multiple snowball with Cohen (RMSC) process sampling which combines the advantages of random sampling and snowball sampling is proposed in this paper. It has the ability to explore global information and discover the local structure at the same time. The experiments indicate that this novel sampling method could keep the similarity between sampling subnet and original network on degree distribution, connectivity rate and average shortest path. This method is applicable to the situation where the prior knowledge about degree distribution of original network is not sufficient.

  12. Bioassessment of Choghakhor Wetland using Benthic Macroinvertebrates

    Directory of Open Access Journals (Sweden)

    P. Fathi

    2016-05-01

    Full Text Available In present study, besides investigating benthic communities and their demographics in Choghakhor wetland, the water quality has been evaluated and classified. Then, 10 stations were selected and sampling of benthos was done every 45 days since April 2010 to March 2011, with 3 replications at each station. Samples were obtained by Ekman grab Sampler (surface 400 cm2. The collected samples were separated and fixed by formalin (4%. The Macroinvertebrates samples were identified and counted in laboratory. Generally 25 families of benthic macroinvertebrates belonging to 5 classes and 12 orders were identified. The results were calculated as community measures, including total richness, Shannon - Wiener diversity index and Hilsenhoff Biological index at family level. The results obtained from temporal and spatial changes of data (Statgeraphics software and water qualitative classification using Shannon diversity index conformed to biological Hilsenhoff index. And finally, water quality of wetland was assessed to be polluted in average to high level. According to this study findings, it seems that, these indicators could be used as useful tools for evaluating water supplies quality.

  13. Aquatic-macroinvertebrate communities of Prairie-Pothole wetlands and lakes under a changed climate

    Science.gov (United States)

    McLean, Kyle I.; Mushet, David M.; Renton, David A.; Stockwell, Craig A.

    2016-01-01

    Understanding how aquatic-macroinvertebrate communities respond to changes in climate is important for biodiversity conservation in the Prairie Pothole Region and other wetland-rich landscapes. We sampled macroinvertebrate communities of 162 wetlands and lakes previously sampled from 1966 to 1976, a much drier period compared to our 2012–2013 sampling timeframe. To identify possible influences of a changed climate and predation pressures on macroinvertebrates, we compared two predictors of aquatic-macroinvertebrate communities: ponded-water dissolved-ion concentration and vertebrate-predator presence/abundance. Further, we make inferences of how macroinvertebrate communities were structured during the drier period when the range of dissolved-ion concentrations was much greater and fish occurrence in aquatic habitats was rare. We found that aquatic-macroinvertebrate community structure was influenced by dissolved-ion concentrations through a complex combination of direct and indirect relationships. Ion concentrations also influenced predator occurrence and abundance, which indirectly affected macroinvertebrate communities. It is important to consider both abiotic and biotic gradients when predicting how invertebrate communities will respond to climate change. Generally, in the wetlands and lakes we studied, freshening of ponded water resulted in more homogenous communities than occurred during a much drier period when salinity range among sites was greater.

  14. Effects of anthropogenic silt on aquatic macroinvertebrates and abiotic variables in streams in the Brazilian Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Couceiro, Sheyla Regina Marques; Hamada, Neusa [Inst. Nacional de Pesquisas da Amazonia, Coordenacao de Pesquisas em Entomologia, Manaus, AM (Brazil); Forsberg, Bruce Rider [Inst. Nacional de Pesquisas da Amazonia, Coordenacao de Pesquisas em Entomologia, Manaus, AM (Brazil); Inst. Nacional de Pesquisas da Amazonia, Coordenacao de Pesquisas em Ecologia, Manaus, AM (Brazil); Padovesi-Fonseca, Claudia [Univ. de Brasilia, Dept. de Ecologia, Brasilia, DF (Brazil)

    2010-01-15

    Purpose: While environmental risks associated with petroleum extraction such as oil spills or leaks are relatively well known, little attention has been given to the impacts of silt. The increase in petroleum exploitation in Amazonia has resulted in sediment input to aquatic systems, with impacts on their biodiversity. Here we use a combination of field measurements and statistical analyses to evaluate the impacts of anthropogenic silt derived from the construction of roads, borrow pits, and wells during the terrestrial development of gas and oil, on macroinvertebrate communities in streams of the Urucu Petroleum Province in the Central Brazilian Amazon. Material and methods: Ten impacted and nine non-impacted streams were sampled in January, April, and November of 2007. Macroinvertebrates were sampled along a 100-m continuous reach in each stream at 10-m intervals using a dip net. Abiotic variables including, a siltation index (SI), suspended inorganic sediment (SIS), sediment color index (SCI), suspend organic sediment (SOS), pH, electrical conductivity, dissolved oxygen, temperature, water velocity, channel width, and depth, were measured at three equidistant points in each stream ({proportional_to}30-m intervals). Results and discussion: SI did not differ between impacted and undisturbed streams. SIS was higher and SCI lower (more reddish) in impacted than in non-impacted streams. SCI had a positive and SIS a negative effect on both macroinvertebrate richness and density. SIS and SCI also influenced macrophyte taxonomic composition. In impacted streams, taxonomic richness and density were 1.5 times lower than in non-impacted streams. No taxon was significantly associated with impacted streams. SIS was positively correlated with SOS and electrical conductivity while SCI was negatively correlated with SOS, electrical conductivity, and pH. The lack of difference in SI between impacted and nonimpacted streams suggests that anthropogenic sediment does not accumulate

  15. Ecological assessment of the Tajan river using feeding groups of benthic macroinvertebrates and biotic indices

    Directory of Open Access Journals (Sweden)

    M Sharifinia

    2012-06-01

    Full Text Available One of the best practical methods to understand ecological status of a water body and determine impacts of human intervention in reducing water quality is using benthic macroinvertebrates as assessment tools for monitoring their biological integrity and health. The Tajan River is one of the rivers of Caspian Southernsub-basin that drains the Caspian Sea. Macroinvertebrate samples were taken using Surber’s sampler (40 x 40 cm and 100µ mesh size in 45 day intervals with 3 replicates in each sampling site for a period of one year (May 2010 to May 2011. The collected organisms were preserved in 4% formalin solution and transferred to the laboratory for identification and counting. Six different functional feeding groups of macroinvertebrate e.g. Collector-gathering, Collector-filtering, Predator, Collector-gathering /Scraper, Predator/Collector-gathering and Scraper were determined. Feeding groups of Collector-gathering, Collector-filtering and Collector-gathering /Scraper were relatively dominant in comparison to other groups. Groups of Collector-filtering and Collector-gathering were dominant in slightly and heavily polluted stations, respectively. In this study population structure measures including abundance, EPT percent and the EPT and EPT/CHIR indics were mearsured. Species diversity, species richness were also determined using Shannon- Weiner, Margalef and Jacardindics. The minimum and maximum values of Hilsenhoff biotic index were observedin stations 1 (4.29 and 5 (5.57, respectively. Moreover, the highest and lowest values of BMWP/ASPT were observed in station 1 (4.51 and 5 (3.25, respectively. Evaluation of indicators revealed less water quality at stations 2, 3 and 5 which located at the lowermost of fish farms and effluent of factory. This reduction might be implicated to the effluents of water damps from fish farms running into the stream as diversity and total abundance (% of sociable macroinvertebrates decreased and that of

  16. Benthic macroinvertebrates in Italian rice fields

    Directory of Open Access Journals (Sweden)

    Daniela Lupi

    2013-02-01

    Full Text Available Rice fields can be considered man-managed temporary wetlands. Five rice fields handled with different management strategies, their adjacent channels, and a spring were analysed by their benthic macroinvertebrate community to i evaluate the role of rice agroe- cosystem in biodiversity conservation; ii find indicator species which can be used to compare the ecological status of natural wetlands with rice agroecosystems; and iii find the influence of environmental variables on biodiversity. Different methods of data analysis with increasing degree of complexity – from diversity index up to sophisticated multivariate analysis – were used. The investigation provided a picture of benthic macroinvertebrates inhabiting rice agroecosystems where 173 taxa were identified, 89 of which detected in rice paddies. Among them, 4 phyla (Mollusca, Annelida, Nematomorpha, and Arthropoda, 8 classes (Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Gordioida, Insecta, Branchiopoda, and Malacostraca, 24 orders, 68 families, 127 genera and 159 species have been found. Ten threatened and 3 invasive species were detected in the habitats examined. The information obtained by the different methods of data analysis allowed a more comprehensive view on the value of the components of rice agroecosystems. Data analyses highlighted significant differences between habitats (feeding channel and rice field, with higher diversity observed in channels, and emphasised the role of the water chemical-physical parameters. The period of water permanence in rice fields resulted to be only one of the factors influencing the community of benthic macroinvertebrates. The presence of rare/endangered species allowed characterising some stations, but it was less informative about management strategies in rice paddies because most of these species were absent in rice fields.

  17. Isonychia spp. and macroinvertebrate community responses to stressors in streams utilizing the benthic in situ toxicity identification evaluation (BiTIE) method

    Energy Technology Data Exchange (ETDEWEB)

    Custer, Kevin W. [Department of Earth and Environmental Sciences, Wright State University, 127 Allyn Hall, 3640 Colonel Glenn Highway, Dayton, OH 45435 (United States)], E-mail: custer.4@wright.edu; Burton, G. Allen [Department of Earth and Environmental Sciences, Wright State University, 127 Allyn Hall, 3640 Colonel Glenn Highway, Dayton, OH 45435 (United States)

    2008-01-15

    Exposures of caged organisms in situ have proven to be a useful way to improve exposure realism and link to stressor effects in aquatic assessments of hazard or risk. A novel cage system, the benthic in situ toxicity identification evaluation (BiTIE), was developed for benthic macroinvertebrates (surrogate species, resident populations and communities) to separate low and high flow effects, and major chemical classes of stressors in streams. Three resin types were used to separate the chemical stressors in the streams Honey Creek and Little Beavercreek, Ohio, USA: Dowex{sup TM} Optipore{sup TM} (non-polar organics), zeolite (ammonia), and polywool (control). Isonychia spp. sensitivity was compared to Chironomus tentans, and no significant differences were found (p > 0.05). Isonychia spp. growth (length) showed a stressor response in the zeolite treatments, and community testing revealed improved metric responses in the Dowex{sup TM} treatments. The BiTIE chamber system demonstrated stressor-response relationships using sublethal and multimetric endpoints. - Use of an indigenous aquatic insect and benthic macroinvertebrate communities allows for discerning the stressors in low and high flows with an in situ TIE approach.

  18. Isonychia spp. and macroinvertebrate community responses to stressors in streams utilizing the benthic in situ toxicity identification evaluation (BiTIE) method

    International Nuclear Information System (INIS)

    Custer, Kevin W.; Burton, G. Allen

    2008-01-01

    Exposures of caged organisms in situ have proven to be a useful way to improve exposure realism and link to stressor effects in aquatic assessments of hazard or risk. A novel cage system, the benthic in situ toxicity identification evaluation (BiTIE), was developed for benthic macroinvertebrates (surrogate species, resident populations and communities) to separate low and high flow effects, and major chemical classes of stressors in streams. Three resin types were used to separate the chemical stressors in the streams Honey Creek and Little Beavercreek, Ohio, USA: Dowex TM Optipore TM (non-polar organics), zeolite (ammonia), and polywool (control). Isonychia spp. sensitivity was compared to Chironomus tentans, and no significant differences were found (p > 0.05). Isonychia spp. growth (length) showed a stressor response in the zeolite treatments, and community testing revealed improved metric responses in the Dowex TM treatments. The BiTIE chamber system demonstrated stressor-response relationships using sublethal and multimetric endpoints. - Use of an indigenous aquatic insect and benthic macroinvertebrate communities allows for discerning the stressors in low and high flows with an in situ TIE approach

  19. Sampling method of environmental radioactivity monitoring

    International Nuclear Information System (INIS)

    1984-01-01

    This manual provides sampling methods of environmental samples of airborne dust, precipitated dust, precipitated water (rain or snow), fresh water, soil, river sediment or lake sediment, discharged water from a nuclear facility, grains, tea, milk, pasture grass, limnetic organisms, daily diet, index organisms, sea water, marine sediment, marine organisms, and that for tritium and radioiodine determination for radiation monitoring from radioactive fallout or radioactivity release by nuclear facilities. This manual aims at the presentation of standard sampling procedures for environmental radioactivity monitoring regardless of monitoring objectives, and shows preservation method of environmental samples acquired at the samplingpoint for radiation counting for those except human body. Sampling techniques adopted in this manual is decided by the criteria that they are suitable for routine monitoring and any special skillfulness is not necessary. Based on the above-mentioned principle, this manual presents outline and aims of sampling, sampling position or object, sampling quantity, apparatus, equipment or vessel for sampling, sampling location, sampling procedures, pretreatment and preparation procedures of a sample for radiation counting, necessary recording items for sampling and sample transportation procedures. Special attention is described in the chapter of tritium and radioiodine because these radionuclides might be lost by the above-mentioned sample preservation method for radiation counting of less volatile radionuclides than tritium or radioiodine. (Takagi, S.)

  20. Macroinvertebrate distribution and aquatic ecology in the Ruoergai (Zoige) Wetland, the Yellow River source region

    Science.gov (United States)

    Zhao, Na; Xu, Mengzhen; Li, Zhiwei; Wang, Zhaoyin; Zhou, Hanmi

    2017-09-01

    The Ruoergai (Zoige) Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies: rivers, oxbow lakes, and marsh wetlands. In this study, macroinvertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The river ecology was particular in the Ruoergai Wetland with the high beta diversity of macroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT (Ephemeroptera, Plecoptera, Trichoptera). To maintain high alpha diversity of macroinvertebrates macroinvertebrates in the Ruoergai Wetland, moderate connectivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

  1. Mixed Methods Sampling: A Typology with Examples

    Science.gov (United States)

    Teddlie, Charles; Yu, Fen

    2007-01-01

    This article presents a discussion of mixed methods (MM) sampling techniques. MM sampling involves combining well-established qualitative and quantitative techniques in creative ways to answer research questions posed by MM research designs. Several issues germane to MM sampling are presented including the differences between probability and…

  2. ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

    International Nuclear Information System (INIS)

    Nelsen, L.A.

    2009-01-01

    The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining

  3. ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

    Energy Technology Data Exchange (ETDEWEB)

    NELSEN LA

    2009-01-30

    The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining.

  4. Qualitative Macroinvertebrate Assessment of Crouch Branch, June 1999

    International Nuclear Information System (INIS)

    Specht, W.L.

    1999-01-01

    An assessment of the macroinvertebrate community of Crouch Branch was performed in June 1999 to determine if effluent from the H-02 outfall is impairing the quality of the stream. Concurrent samples were collected for metals analyses (copper and zinc). The results of the study indicate that the stream is most impaired just downstream from the H-02 outfall and that the quality of the stream biota improves with increasing distance from the outfall. Conversely, macroinvertebrate habitat quality is best just downstream from the H-02 outfall. The midreaches of the stream contain very poor habitat quality, and the lower reaches of the stream, contain habitat of intermediate quality. Although much of the stream has degraded habitat due to channel erosion and scouring, there is strong evidence to suggest that the impairment is due to elevated concentrations of copper and zinc that are present in the H-02 effluent. A comparison of macroinvertebrate data collected in 1997 to the data collected in this study indicates that the macroinvertebrate community of Crouch Branch has improved markedly in the last two years

  5. [Effect of environmental factors on macroinvertebrate community structure in the Huntai River basin in the Huntai River basin].

    Science.gov (United States)

    Li, Yan-li; Li, Yan-fen; Xu, Zong-xue

    2015-01-01

    In May-June 2012, macroinvertebrates were investigated at 66 sampling sites in the Huntai River basin in Northeast of China. A total of 72 macrobenthos species were collected, of which, 51 species (70.83%) were aquatic insects, 10 species (13.89%) were mollusks, 7 species (9.72%) were annelids, and 4 species (5.56%) were arthropods. First, 13 candidate metrics (EPT taxa, Dominant taxon%, Ephemeroptera%, Trichoptera%, mollusks%, Heptageniidae/Ephemeroptera; Hydropsychidae/ Trichoptera, Oligochaeta%, intolerant taxon% , tolerant taxon%, Collector%, Clingers%, Shannon-wiener index.) which belonged to six types were chosen to represent macroinvertebrate community structure by correlation analysis. Then, relationships between anthropogenic and physiography pressures and macroinvertebrate community structure variables were measured using redundancy analysis. Then, this study compared the relative influences of anthropogenic and physiographic pressures on macroinvertebrate community structure and the relative influences of anthropogenic pressures at reach, riparian and catchment scales by pRDA. The results showed all environmental factors explained 72.23% of the variation of macroinvertebrate community structure. In addition, a large proportion of the explained variability in macroinvertebrate community structure was related to anthropogenic pressures (48.9%) and to physiographic variables (11.8%), anthropogenic pressures at reach scale influenced most significantly macroinvertebrate community structure which explained 35.3% of the variation of macroinvertebrate community structure. pH, habitat, TN, CODMn, hardness, conductivity, total dissolved particle and ammonia influenced respectively explained 4%, 3.6%, 1.8%, 1.7%, 1.7%, 0.9%, 0.9% and 0.9% of the variation of macroinvertebrate community structure. The land use at riparian and catchment scale respectively explained 10% and 7% of the variation of macroinvertebrate community structure. Finally, the relationships of

  6. Assessment of ecological quality of the Tajan river in Iran using a multimetric macroinvertebrate index and species traits

    NARCIS (Netherlands)

    Aazami, J.; Esmaili Sari, A.; Abdoli, A.; Sohrabi, H.; Brink, van den P.J.

    2015-01-01

    The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were

  7. Sample normalization methods in quantitative metabolomics.

    Science.gov (United States)

    Wu, Yiman; Li, Liang

    2016-01-22

    To reveal metabolomic changes caused by a biological event in quantitative metabolomics, it is critical to use an analytical tool that can perform accurate and precise quantification to examine the true concentration differences of individual metabolites found in different samples. A number of steps are involved in metabolomic analysis including pre-analytical work (e.g., sample collection and storage), analytical work (e.g., sample analysis) and data analysis (e.g., feature extraction and quantification). Each one of them can influence the quantitative results significantly and thus should be performed with great care. Among them, the total sample amount or concentration of metabolites can be significantly different from one sample to another. Thus, it is critical to reduce or eliminate the effect of total sample amount variation on quantification of individual metabolites. In this review, we describe the importance of sample normalization in the analytical workflow with a focus on mass spectrometry (MS)-based platforms, discuss a number of methods recently reported in the literature and comment on their applicability in real world metabolomics applications. Sample normalization has been sometimes ignored in metabolomics, partially due to the lack of a convenient means of performing sample normalization. We show that several methods are now available and sample normalization should be performed in quantitative metabolomics where the analyzed samples have significant variations in total sample amounts. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Analytical approaches used in stream benthic macroinvertebrate biomonitoring programs of State agencies in the United States

    Science.gov (United States)

    Carter, James L.; Resh, Vincent H.

    2013-01-01

    Biomonitoring programs based on benthic macroinvertebrates are well-established worldwide. Their value, however, depends on the appropriateness of the analytical techniques used. All United States State, benthic macroinvertebrate biomonitoring programs were surveyed regarding the purposes of their programs, quality-assurance and quality-control procedures used, habitat and water-chemistry data collected, treatment of macroinvertebrate data prior to analysis, statistical methods used, and data-storage considerations. State regulatory mandates (59 percent of programs), biotic index development (17 percent), and Federal requirements (15 percent) were the most frequently reported purposes of State programs, with the specific tasks of satisfying the requirements for 305b/303d reports (89 percent), establishment and monitoring of total maximum daily loads, and developing biocriteria being the purposes most often mentioned. Most states establish reference sites (81 percent), but classify them using State-specific methods. The most often used technique for determining the appropriateness of a reference site was Best Professional Judgment (86 percent of these states). Macroinvertebrate samples are almost always collected by using a D-frame net, and duplicate samples are collected from approximately 10 percent of sites for quality assurance and quality control purposes. Most programs have macroinvertebrate samples processed by contractors (53 percent) and have identifications confirmed by a second taxonomist (85 percent). All States collect habitat data, with most using the Rapid Bioassessment Protocol visual-assessment approach, which requires ~1 h/site. Dissolved oxygen, pH, and conductivity are measured in more than 90 percent of programs. Wide variation exists in which taxa are excluded from analyses and the level of taxonomic resolution used. Species traits, such as functional feeding groups, are commonly used (96 percent), as are tolerance values for organic pollution

  9. Fluidics platform and method for sample preparation

    Science.gov (United States)

    Benner, Henry W.; Dzenitis, John M.

    2016-06-21

    Provided herein are fluidics platforms and related methods for performing integrated sample collection and solid-phase extraction of a target component of the sample all in one tube. The fluidics platform comprises a pump, particles for solid-phase extraction and a particle-holding means. The method comprises contacting the sample with one or more reagents in a pump, coupling a particle-holding means to the pump and expelling the waste out of the pump while the particle-holding means retains the particles inside the pump. The fluidics platform and methods herein described allow solid-phase extraction without pipetting and centrifugation.

  10. Optimisation of the Monitoring Strategy of Macroinvertebrate Communities in the River Dender, in Relation to the EU Water Framework Directive

    Directory of Open Access Journals (Sweden)

    Tom P. D’heygere

    2002-01-01

    Full Text Available The Dender basin in Flanders (Belgium was used as a case study to implement the European Union (EU Water Framework Directive. During the last 5 years, ample research on pollution loads and ecological water quality has been done on the Dender River. In addition to biological sampling of macroinvertebrates and fish, automated measurement stations were also used to investigate the spatial-temporal variability of the physical-chemical water quality. This research revealed that the pollution of the Dender River is highly variable. The high nutrient loads result in severe algae blooms during summer, leading to very complex diurnal processes. In this paper, the monitoring strategy for the assessment of the biological water quality in the Dender basin has been reviewed in relation to the EU Water Framework Directive. For this, seasonal macroinvertebrate data were collected and assessed. General trends and hidden structures in these data were analysed by means of classification trees, using different inputs (seasons, river types, and subbasins. Validation of the results was obtained by applying statistical methods. Analysis about the presence and abundance of the macroinvertebrates revealed that there is a distinct difference between the biological water quality in the Dender stem river and its tributaries. There are also seasonal differences between the macroinvertebrate communities when the Dender and its tributaries are examined separately. An optimised monitoring strategy is proposed based on these results and the EU Water Framework Directive. This includes two monitoring campaigns in summer and winter every 3 years. Furthermore, a cyclic monitoring scheme was developed to minimise sampling efforts.

  11. Macroinvertebrates associated with two submerged macrophytes ...

    African Journals Online (AJOL)

    Macroinvertebrates associated with two submerged macrophytes, Lagarosiphon ilicifolius and Vallisneria aethiopica , in the Sanyati Basin, Lake Kariba, Zimbabwe: effect of plant morphological complexity.

  12. The macroinvertebrates of Magela Creek, Northern Territory

    International Nuclear Information System (INIS)

    Marchant, R.

    1982-04-01

    The littoral zones of five permanent billabongs in Magela Creek were sampled monthly for macroinvertebrates. Greatest numbers of taxa and individuals were caught in the late wet season and early dry season in the shallow billabongs; in the deep billabongs, seasonal variations were not so marked. These changes appeared to be associated with the development of macrophytes, which offered food and shelter to the invertebrate fauna. The dominant groups were the Chironomidae, Oligochaetae and Ephemeroptera. The seasonal patterns of the catches were sufficiently consistent for future samples to be able to be compared with these initial ones with some confidence that any changes are real. This work is part of a larger study into the biota and water quality of Magela Creek designed to provide data on aquatic communities before mining of the Ranger uranium deposit starts

  13. Are sugarcane leaf-detritus well colonized by aquatic macroinvertebrates?

    Directory of Open Access Journals (Sweden)

    Luciene Aparecida Leite-Rossi

    Full Text Available AIM: The aim was to compare the kinetics of decomposition and the colonization of leaf litter of two plant species, the native Talauma ovata (pinha-do-brejo and the exotic Saccharum officinarum (sugarcane, by aquatic macroinvertebrates; METHODS: From each substrate, three recipients of colonization were taken from a stream, and the specimens identified to the lowest taxonomic level on days 7, 15, 34, 44, 61 and 75. The debris was weighed at the beginning and end of the experiment and determined their cell wall fractions; RESULTS: The coefficients of mineralization indicated higher velocity decay of organic matter refractory in T. ovata. There was no difference in taxonomic structure of macroinvertebrates, between the two substrates, but the community exhibited distinct functional feeding groups in the peak of colonization, with a greater number of shredders in T. ovata. The successive states of decomposition of the two plant detritus showed distinct macroinvertebrate densities; CONCLUSIONS: The amount and state of the plant biomass were important factors influencing the density and diversity of the macroinvertebrate fauna throughout the process of organic decomposition.

  14. Innovative methods for inorganic sample preparation

    Energy Technology Data Exchange (ETDEWEB)

    Essling, A.M.; Huff, E.A.; Graczyk, D.G.

    1992-04-01

    Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized.

  15. Innovative methods for inorganic sample preparation

    International Nuclear Information System (INIS)

    Essling, A.M.; Huff, E.A.; Graczyk, D.G.

    1992-04-01

    Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized

  16. New methods for sampling sparse populations

    Science.gov (United States)

    Anna Ringvall

    2007-01-01

    To improve surveys of sparse objects, methods that use auxiliary information have been suggested. Guided transect sampling uses prior information, e.g., from aerial photographs, for the layout of survey strips. Instead of being laid out straight, the strips will wind between potentially more interesting areas. 3P sampling (probability proportional to prediction) uses...

  17. Sample preparation method for scanning force microscopy

    CERN Document Server

    Jankov, I R; Szente, R N; Carreno, M N P; Swart, J W; Landers, R

    2001-01-01

    We present a method of sample preparation for studies of ion implantation on metal surfaces. The method, employing a mechanical mask, is specially adapted for samples analysed by Scanning Force Microscopy. It was successfully tested on polycrystalline copper substrates implanted with phosphorus ions at an acceleration voltage of 39 keV. The changes of the electrical properties of the surface were measured by Kelvin Probe Force Microscopy and the surface composition was analysed by Auger Electron Spectroscopy.

  18. Distribution of macroinvertebrates on intertidal rocky shores in Gorgona Island, Colombia (Tropical Eastern Pacific

    Directory of Open Access Journals (Sweden)

    Edgardo Londoño-Cruz

    2014-02-01

    Full Text Available Organisms found on rocky shores must endure harsh environmental conditions during tidal changes but scientific studies on tropical rocky shores are scarce, particularly in Colombian shores. Here we describe the spatial distribution of macroinvertebrates associated to the intertidal rocky ecosystems of Gorgona Island, Colombia (Tropical Eastern Pacific. Sampling was carried out in four localities around the Island: La Ventana and La Camaronera (sampled during October 2010 and La Mancora and El Muelle (sampled during March 2011. Two methodologies were used: rapid ecological assessments for qualitative data and quadrats for quantitative data. The richness, abundance, diversity (Shannon-Wiener H’, and evenness (Pielou J’ of macroinvertebrates were determined for and compared between, using one way ANOVA, each locality and the three intertidal zones of La Ventana (see methods. One hundred twenty-one species of macroinvertebrates were found during the sampling period. In all localities, Mollusca was the richest and most abundant taxon (46% of the species and 59% of the individuals, followed by Crustacea (32% of the species and 33% of the individuals. The other groups accounted for the remaining 22% of the richness and 8% of the abundance. Several studies have demonstrated that mollusks and crustaceans are the richest and most abundant taxa in marine benthic communities. Most of the abundant species found were herbivores. The species composition varied among zones. The results of dominant species for each zone are consistent with the ones observed in other tropical rocky intertidal shores. All response variables showed a decreasing pattern from the low to the high intertidal (in La Ventana. Post-hoc results indicated that the high intertidal, the zone with the harshest environmental conditions, had significantly lower values than the other two zones for all response variables. Comparisons between the low intertidal zones of the different localities

  19. Method and apparatus for sampling atmospheric mercury

    Science.gov (United States)

    Trujillo, Patricio E.; Campbell, Evan E.; Eutsler, Bernard C.

    1976-01-20

    A method of simultaneously sampling particulate mercury, organic mercurial vapors, and metallic mercury vapor in the working and occupational environment and determining the amount of mercury derived from each such source in the sampled air. A known volume of air is passed through a sampling tube containing a filter for particulate mercury collection, a first adsorber for the selective adsorption of organic mercurial vapors, and a second adsorber for the adsorption of metallic mercury vapor. Carbon black molecular sieves are particularly useful as the selective adsorber for organic mercurial vapors. The amount of mercury adsorbed or collected in each section of the sampling tube is readily quantitatively determined by flameless atomic absorption spectrophotometry.

  20. Subrandom methods for multidimensional nonuniform sampling.

    Science.gov (United States)

    Worley, Bradley

    2016-08-01

    Methods of nonuniform sampling that utilize pseudorandom number sequences to select points from a weighted Nyquist grid are commonplace in biomolecular NMR studies, due to the beneficial incoherence introduced by pseudorandom sampling. However, these methods require the specification of a non-arbitrary seed number in order to initialize a pseudorandom number generator. Because the performance of pseudorandom sampling schedules can substantially vary based on seed number, this can complicate the task of routine data collection. Approaches such as jittered sampling and stochastic gap sampling are effective at reducing random seed dependence of nonuniform sampling schedules, but still require the specification of a seed number. This work formalizes the use of subrandom number sequences in nonuniform sampling as a means of seed-independent sampling, and compares the performance of three subrandom methods to their pseudorandom counterparts using commonly applied schedule performance metrics. Reconstruction results using experimental datasets are also provided to validate claims made using these performance metrics. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Assessing disruption of longitudinal connectivity on macroinvertebrate assemblages in a semiarid lowland river

    Directory of Open Access Journals (Sweden)

    Marta Leiva

    2017-12-01

    Full Text Available Abstract Aim: Our aim in this study was evaluate the effects of flow regulation for irrigation on the macroinvertebrate assemblages in a semiarid river. Methods We sampled two reaches in Dulce River; one placed upstream a weir that diverts flow into a network of irrigation channels and the other downstream that weir, in the assessment of the fluvial discontinuity. We assess the differences among reaches and sites, environmental variables, invertebrate density, richness and Shannon-Wiener index applying non-parametric analyses of variance Kruskal Wallis. The similarity percentage analysis (SIMPER was used to identify which species contributed to the dissimilarities on macroinvertebrate assemblage structure. Canonical Correspondence Analysis (CCA was performed with the total set of samples to explore macroinvertebrate distribution in reaches and associations of the assemblages with habitat variables. Results The density, richness and Shannon index values did not show differences between the reaches located upstream and downstream. Beta diversity (Whittaker was 0.72 among upstream sites, 0.56 among downstream sites and higher species turnover (0.73 was obtained between both reaches. The Canonical Correspondence Analysis explained 46.71% of the variance differentiating upstream sites explained by higher values of organic matter of bottom sediments and discharge, high density of Nais communis, Bothrioneurum americanum, Pelomus, Stephensoniana trivandrana, Pristina menoni, P. jenkinae, P.longidentata, P. americana, Dero obtusa, Endotribelos, Heleobia and Turbellaria. The downstream sites were associated to coarser substratum and higher density of Lopescladius, Polypedilum, Cricotopus, Thienamaniella, Cryptochironomus, Baetidae, Nematoda and Corbicula fluminea. Conclusions The low-flow disturbance had effects on the composition of the benthic invertebrate assemblages, but attributes (such as density and richness showed a lower variability probably

  2. Tolerance of benthic macroinvertebrates to organic enrichment in highland streams of northeastern Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Aline Correa Mazzoni

    2014-06-01

    Full Text Available AIM: the aim of this study was to determine the ecological valence of benthic macroinvertebrates at different pollution levels in highland rivers and streams of Rio Grande do Sul; METHODS: the dataset proceeds from samplings performed between 2002-2011 in 35 lotic ecosystems. The Chemical Index was used to determine pollution levels. Indices of richness and Shannon diversity were applied to characterize the structure of benthic communities. The descriptors used to determine taxa's ecological valence were selected according to Coefficient of Variation and regression analyses. Groups of tolerance were identified using Interquartile range and cluster analysis; RESULTS: Conductivity and Chemical Index were the descriptors best related with diversity of benthic macroinvertebrate community. These metrics were used to determine the tolerance range of 38 taxa. Interquartile range and cluster analysis revealed three groups of taxa, according to their occurrence in different levels of pollution: taxa with narrow amplitudes, present at sites with very low or very high load of organic enrichment; taxa with moderate amplitude, found until moderately polluted sites; and taxa with occurrence in widespread environmental conditions. The results, when compared to other studies in Brazil, showed differences in some taxa's tolerance. This observation indicates the need to assess the bioindication potential of these taxa in genus and species level; CONCLUSION: the present study contributes to increase knowledge about the bioindicator potential of benthic macroinvertebrates. Therefore, the study supports an advanced biomonitoring of ecological quality in mountain streams of southern Brazil.

  3. Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

    OpenAIRE

    Miguel CAÑEDO-ARGÜELLES; Maria RIERADEVALL

    2009-01-01

    The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav.) Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain) following the method proposed by Kornijów & Kairesalo (1994). The aims of the study were to: 1) characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2) assess the contribution of elements of the epi...

  4. Sampling of temporal networks: Methods and biases

    Science.gov (United States)

    Rocha, Luis E. C.; Masuda, Naoki; Holme, Petter

    2017-11-01

    Temporal networks have been increasingly used to model a diversity of systems that evolve in time; for example, human contact structures over which dynamic processes such as epidemics take place. A fundamental aspect of real-life networks is that they are sampled within temporal and spatial frames. Furthermore, one might wish to subsample networks to reduce their size for better visualization or to perform computationally intensive simulations. The sampling method may affect the network structure and thus caution is necessary to generalize results based on samples. In this paper, we study four sampling strategies applied to a variety of real-life temporal networks. We quantify the biases generated by each sampling strategy on a number of relevant statistics such as link activity, temporal paths and epidemic spread. We find that some biases are common in a variety of networks and statistics, but one strategy, uniform sampling of nodes, shows improved performance in most scenarios. Given the particularities of temporal network data and the variety of network structures, we recommend that the choice of sampling methods be problem oriented to minimize the potential biases for the specific research questions on hand. Our results help researchers to better design network data collection protocols and to understand the limitations of sampled temporal network data.

  5. Mercury in fish and macroinvertebrates from New York's streams and rivers: A compendium of data sources

    Science.gov (United States)

    Riva-Murray, Karen; Burns, Douglas A.

    2016-01-01

    The U.S. Geological Survey has compiled a list of existing data sets, from selected sources, containing mercury (Hg) concentration data in fish and macroinvertebrate samples that were collected from flowing waters of New York State from 1970 through 2014. Data sets selected for inclusion in this report were limited to those that contain fish and (or) macroinvertebrate data that were collected across broad areas, cover relatively long time periods, and (or) were collected as part of a broader-scale (e.g. national) study or program. In addition, all data sets listed were collected, processed, and analyzed with documented methods, and contain critical sample information (e.g. fish species, fish size, Hg species) that is needed to analyze and interpret the reported Hg concentration data. Fourteen data sets, all from state or federal agencies, are listed in this report, along with selected descriptive information regarding each data source and data set contents. Together, these 14 data sets contain Hg and related data for more than 7,000 biological samples collected from more than 700 unique stream and river locations between 1970 and 2014.

  6. Diversity patterns of temporary wetland macroinvertebrate ...

    African Journals Online (AJOL)

    Although macroinvertebrates are potentially useful for assessing the condition of temporary wetlands, little is yet known about them. Macroinvertebrate assemblages were assessed in 138 temporary wetlands in the south-western Cape, recording 126 taxa. However, predicted richness estimates were all higher than the ...

  7. Macroinvertebrate variation in endorheic depression wetlands in ...

    African Journals Online (AJOL)

    Aquatic macroinvertebrates are rarely used in wetland assessments due to their variation. However, in terms of biodiversity, these invertebrates form an important component of wetland fauna. Spatial and temporal variation of macroinvertebrate assemblages in endorheic depressions (locally referred to as 'pans') in ...

  8. Composition and dynamic of benthic macroinvertebrates community ...

    African Journals Online (AJOL)

    the purpose to analyze the taxonomic composition, the structure of benthic macroinvertebrates community and the composite ... differences relative to the spatial and temporal variation in the taxonomic composition. ... changes in the structure of macroinvertebrates community ... 2007) with an annual growth rate of 2.4% rely.

  9. Short Note An integrated remote sampling approach for aquatic ...

    African Journals Online (AJOL)

    A sampling method and apparatus for collecting meaningful and quantifiable samples of aquatic macroinvertebrates, and the macrophytes they are associated with, are presented. Where physical danger from wildlife is a significant factor, especially in Africa, this apparatus offers some safety in that it can be operated from a ...

  10. Chapter 12. Sampling and analytical methods

    International Nuclear Information System (INIS)

    Busenberg, E.; Plummer, L.N.; Cook, P.G.; Solomon, D.K.; Han, L.F.; Groening, M.; Oster, H.

    2006-01-01

    When water samples are taken for the analysis of CFCs, regardless of the sampling method used, contamination of samples by contact with atmospheric air (with its 'high' CFC concentrations) is a major concern. This is because groundwaters usually have lower CFC concentrations than those waters which have been exposed to the modern air. Some groundwaters might not contain CFCs and, therefore, are most sensitive to trace contamination by atmospheric air. Thus, extreme precautions are needed to obtain uncontaminated samples when groundwaters, particularly those with older ages, are sampled. It is recommended at the start of any CFC investigation that samples from a CFC-free source be collected and analysed, as a check upon the sampling equipment and methodology. The CFC-free source might be a deep monitoring well or, alternatively, CFC-free water could be carefully prepared in the laboratory. It is especially important that all tubing, pumps and connection that will be used in the sampling campaign be checked in this manner

  11. Influence of peak flow changes on the macroinvertebrate drift downstream of a Brazilian hydroelectric dam.

    Science.gov (United States)

    Castro, D M P; Hughes, R M; Callisto, M

    2013-11-01

    Successive daily peak flows from hydropower plants can disrupt aquatic ecosystems and alter the composition and structure of macroinvertebrates downstream. We evaluated the influence of peak flow changes on macroinvertebrate drift downstream of a hydroelectric plant as a basis for determining ecological flows that might reduce the disturbance of aquatic biota. The aim of this study was to assess the influence of flow fluctuations on the seasonal and daily drift patterns of macroinvertebrates. We collected macroinvertebrates during fixed flow rates (323 m3.s-1 in the wet season and 111 m3.s-1 in the dry season) and when peak flows fluctuated (378 to 481 m3.s-1 in the wet season, and 109 to 173 m3.s-1 in the dry season) in 2010. We collected 31,924 organisms belonging to 46 taxa in the four sampling periods. Taxonomic composition and densities of drifting invertebrates differed between fixed and fluctuating flows, in both wet and dry seasons, but family richness varied insignificantly. We conclude that macroinvertebrate assemblages downstream of dams are influenced by daily peak flow fluctuations. When making environmental flow decisions for dams, it would be wise to consider drifting macroinvertebrates because they reflect ecological changes in downstream biological assemblages.

  12. Sampling and examination methods used for TMI-2 samples

    International Nuclear Information System (INIS)

    Marley, A.W.; Akers, D.W.; McIsaac, C.V.

    1988-01-01

    The purpose of this paper is to summarize the sampling and examination techniques that were used in the collection and analysis of TMI-2 samples. Samples ranging from auxiliary building air to core debris were collected and analyzed. Handling of the larger samples and many of the smaller samples had to be done remotely and many standard laboratory analytical techniques were modified to accommodate the extremely high radiation fields associated with these samples. The TMI-2 samples presented unique problems with sampling and the laboratory analysis of prior molten fuel debris. 14 refs., 8 figs

  13. Sampling methods for terrestrial amphibians and reptiles.

    Science.gov (United States)

    Paul Stephen Corn; R. Bruce. Bury

    1990-01-01

    Methods described for sampling amphibians and reptiles in Douglas-fir forests in the Pacific Northwest include pitfall trapping, time-constrained collecting, and surveys of coarse woody debris. The herpetofauna of this region differ in breeding and nonbreeding habitats and vagility, so that no single technique is sufficient for a community study. A combination of...

  14. Passive sampling methods for contaminated sediments

    DEFF Research Database (Denmark)

    Peijnenburg, Willie J.G.M.; Teasdale, Peter R.; Reible, Danny

    2014-01-01

    “Dissolved” concentrations of contaminants in sediment porewater (Cfree) provide a more relevant exposure metric for risk assessment than do total concentrations. Passive sampling methods (PSMs) for estimating Cfree offer the potential for cost-efficient and accurate in situ characterization...

  15. Turbidity threshold sampling: Methods and instrumentation

    Science.gov (United States)

    Rand Eads; Jack Lewis

    2001-01-01

    Traditional methods for determining the frequency of suspended sediment sample collection often rely on measurements, such as water discharge, that are not well correlated to sediment concentration. Stream power is generally not a good predictor of sediment concentration for rivers that transport the bulk of their load as fines, due to the highly variable routing of...

  16. Statistical sampling method for releasing decontaminated vehicles

    International Nuclear Information System (INIS)

    Lively, J.W.; Ware, J.A.

    1996-01-01

    Earth moving vehicles (e.g., dump trucks, belly dumps) commonly haul radiologically contaminated materials from a site being remediated to a disposal site. Traditionally, each vehicle must be surveyed before being released. The logistical difficulties of implementing the traditional approach on a large scale demand that an alternative be devised. A statistical method (MIL-STD-105E, open-quotes Sampling Procedures and Tables for Inspection by Attributesclose quotes) for assessing product quality from a continuous process was adapted to the vehicle decontamination process. This method produced a sampling scheme that automatically compensates and accommodates fluctuating batch sizes and changing conditions without the need to modify or rectify the sampling scheme in the field. Vehicles are randomly selected (sampled) upon completion of the decontamination process to be surveyed for residual radioactive surface contamination. The frequency of sampling is based on the expected number of vehicles passing through the decontamination process in a given period and the confidence level desired. This process has been successfully used for 1 year at the former uranium mill site in Monticello, Utah (a CERCLA regulated clean-up site). The method forces improvement in the quality of the decontamination process and results in a lower likelihood that vehicles exceeding the surface contamination standards are offered for survey. Implementation of this statistical sampling method on Monticello Projects has resulted in more efficient processing of vehicles through decontamination and radiological release, saved hundreds of hours of processing time, provided a high level of confidence that release limits are met, and improved the radiological cleanliness of vehicles leaving the controlled site

  17. Macroinvertebrates as indicators of fish absence in naturally fishless lakes

    Science.gov (United States)

    Schilling, Emily Gaenzle; Loftin, C.S.; Huryn, Alexander D.

    2009-01-01

    1. Little is known about native communities in naturally fishless lakes in eastern North America, a region where fish stocking has led to a decline in these habitats. 2. Our study objectives were to: (i) characterise and compare macroinvertebrate communities in fishless lakes found in two biophysical regions of Maine (U.S.A.): kettle lakes in the eastern lowlands and foothills and headwater lakes in the central and western mountains; (ii) identify unique attributes of fishless lake macroinvertebrate communities compared to lakes with fish and (iii) develop a method to efficiently identify fishless lakes when thorough fish surveys are not possible. 3. We quantified macroinvertebrate community structure in the two physiographic fishless lake types (n = 8 kettle lakes; n = 8 headwater lakes) with submerged light traps and sweep nets. We also compared fishless lake macroinvertebrate communities to those in fish-containing lakes (n = 18) of similar size, location and maximum depth. We used non-metric multidimensional scaling to assess differences in community structure and t-tests for taxon-specific comparisons between lakes. 4. Few differences in macroinvertebrate communities between the two physiographic fishless lake types were apparent. Fishless and fish-containing lakes had numerous differences in macroinvertebrate community structure, abundance, taxonomic composition and species richness. Fish presence or absence was a stronger determinant of community structure in our study than differences in physical conditions relating to lake origin and physiography. 5. Communities in fishless lakes were more speciose and abundant than in fish-containing lakes, especially taxa that are large, active and free-swimming. Families differing in abundance and taxonomic composition included Notonectidae, Corixidae, Gyrinidae, Dytiscidae, Aeshnidae, Libellulidae and Chaoboridae. 6. We identified six taxa unique to fishless lakes that are robust indicators of fish absence: Graphoderus

  18. POP bioaccumulation in macroinvertebrates of alpine freshwater systems

    International Nuclear Information System (INIS)

    Bizzotto, E.C.; Villa, S.; Vighi, M.

    2009-01-01

    This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in the predators is likely to be related to their greater lipid content compared to that of other feeding groups. - Influence of POP release in glacial-fed streams, enhanced by global warming, on pristine aquatic ecosystems.

  19. Macroinvertebrate community change associated with the severity of streamflow alteration

    Science.gov (United States)

    Carlisle, Daren M.; Eng, Kenny; Nelson, S.M.

    2014-01-01

    Natural streamflows play a critical role in stream ecosystems, yet quantitative relations between streamflow alteration and stream health have been elusive. One reason for this difficulty is that neither streamflow alteration nor ecological responses are measured relative to their natural expectations. We assessed macroinvertebrate community condition in 25 mountain streams representing a large gradient of streamflow alteration, which we quantified as the departure of observed flows from natural expectations. Observed flows were obtained from US Geological Survey streamgaging stations and discharge records from dams and diversion structures. During low-flow conditions in September, samples of macroinvertebrate communities were collected at each site, in addition to measures of physical habitat, water chemistry and organic matter. In general, streamflows were artificially high during summer and artificially low throughout the rest of the year. Biological condition, as measured by richness of sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera) and taxonomic completeness (O/E), was strongly and negatively related to the severity of depleted flows in winter. Analyses of macroinvertebrate traits suggest that taxa losses may have been caused by thermal modification associated with streamflow alteration. Our study yielded quantitative relations between the severity of streamflow alteration and the degree of biological impairment and suggests that water management that reduces streamflows during winter months is likely to have negative effects on downstream benthic communities in Utah mountain streams. 

  20. Benthic Macroinvertebrate Communities in the Northern Tributaries of the “Iron Gates” Gorge (Danube River

    Directory of Open Access Journals (Sweden)

    Curtean-Bănăduc Angela

    2014-12-01

    Full Text Available The paper presents the structure of the benthonic macro-invertebrates communities in the Berzasca, Sirinia, Liubcova, and Mraconia rivers. The results are based on quantitative benthos samples (95 samples, collected in July 2014 from 19 sampling stations within the study area. In longitudinal profile, the benthonic macro-invertebrate communities of the Sirinia, Liubcova and Berzasca rivers displays relatively large structural variability, while the communities of the Mraconia River displays smaller structural variability. The structure of the benthonic macro-invertebrate communities correlated with the biotope characteristics indicates the good ecological status of the analysed rivers, with the exception of the Berzasca River sector downstream of the town of Berzasca and immediately upstream of the Danube junction, a sector with moderate ecological status due to negative effects from man-made modifications in the lotic biotope of the sector.

  1. SAMPLING IN EXTERNAL AUDIT - THE MONETARY UNIT SAMPLING METHOD

    Directory of Open Access Journals (Sweden)

    E. Dascalu

    2016-12-01

    Full Text Available This article approaches the general issue of diminishing the evidence investigation space in audit activities, by means of sampling techniques, given that in the instance of a significant data volume an exhaustive examination of the assessed popula¬tion is not possible and/or effective. The general perspective of the presentation involves dealing with sampling risk, in essence, the risk that a selected sample may not be representative for the overall population, in correlation with the audit risk model and with the component parts of this model (inherent risk, control risk and non detection risk and highlights the inter-conditionings between these two models.

  2. Different methods for volatile sampling in mammals.

    Directory of Open Access Journals (Sweden)

    Marlen Kücklich

    Full Text Available Previous studies showed that olfactory cues are important for mammalian communication. However, many specific compounds that convey information between conspecifics are still unknown. To understand mechanisms and functions of olfactory cues, olfactory signals such as volatile compounds emitted from individuals need to be assessed. Sampling of animals with and without scent glands was typically conducted using cotton swabs rubbed over the skin or fur and analysed by gas chromatography-mass spectrometry (GC-MS. However, this method has various drawbacks, including a high level of contaminations. Thus, we adapted two methods of volatile sampling from other research fields and compared them to sampling with cotton swabs. To do so we assessed the body odor of common marmosets (Callithrix jacchus using cotton swabs, thermal desorption (TD tubes and, alternatively, a mobile GC-MS device containing a thermal desorption trap. Overall, TD tubes comprised most compounds (N = 113, with half of those compounds being volatile (N = 52. The mobile GC-MS captured the fewest compounds (N = 35, of which all were volatile. Cotton swabs contained an intermediate number of compounds (N = 55, but very few volatiles (N = 10. Almost all compounds found with the mobile GC-MS were also captured with TD tubes (94%. Hence, we recommend TD tubes for state of the art sampling of body odor of mammals or other vertebrates, particularly for field studies, as they can be easily transported, stored and analysed with high performance instruments in the lab. Nevertheless, cotton swabs capture compounds which still may contribute to the body odor, e.g. after bacterial fermentation, while profiles from mobile GC-MS include only the most abundant volatiles of the body odor.

  3. Method and apparatus for continuous sampling

    International Nuclear Information System (INIS)

    Marcussen, C.

    1982-01-01

    An apparatus and method for continuously sampling a pulverous material flow includes means for extracting a representative subflow from a pulverous material flow. A screw conveyor is provided to cause the extracted subflow to be pushed upwardly through a duct to an overflow. Means for transmitting a radiation beam transversely to the subflow in the duct, and means for sensing the transmitted beam through opposite pairs of windows in the duct are provided to measure the concentration of one or more constituents in the subflow. (author)

  4. Comparisons of methods for generating conditional Poisson samples and Sampford samples

    OpenAIRE

    Grafström, Anton

    2005-01-01

    Methods for conditional Poisson sampling (CP-sampling) and Sampford sampling are compared and the focus is on the efficiency of the methods. The efficiency is investigated by simulation in different sampling situations. It was of interest to compare methods since new methods for both CP-sampling and Sampford sampling were introduced by Bondesson, Traat & Lundqvist in 2004. The new methods are acceptance rejection methods that use the efficient Pareto sampling method. They are found to be ...

  5. Macroinvertebrate community responses to gravel augmentation in a high-gradient, Southeastern regulated river

    Energy Technology Data Exchange (ETDEWEB)

    McManamay, Ryan A [ORNL; Orth, Dr. Donald J [Virginia Polytechnic Institute and State University; Dolloff, Dr. Charles A [United States Department of Agriculture (USDA), United States Forest Service (USFS) and Virginia Pol

    2013-01-01

    Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread practice, it is essential to evaluate the biotic response to restoration projects in order to improve the efficacy of future applications. The purpose of our study was to evaluate the response of the macroinvertebrate community to gravel addition in a high-gradient, regulated river in western North Carolina. We collected benthic macroinvertebrate samples from gravel-enhanced areas and unenhanced areas for 1 season before gravel addition, and for 4 seasons afterwards. Repeated measures multivariate analysis of variance indicated that the responses of macroinvertebrates to gravel addition were generally specific to individual taxa or particular functional feeding groups and did not lead to consistent patterns in overall family richness, diversity, density, or evenness. Non-metric multi-dimensional scaling showed that shifts in macroinvertebrate community composition were temporary and dependent upon site conditions and season. Correlations between macroinvertebrate response variables and substrate microhabitat variables existed with or without the inclusion of data from enhanced areas, which suggests that substrate-biotic relationships were present before gravel addition. A review of the current literature suggests that the responses of benthic macroinvertebrates to substrate restoration are inconsistent and dependent upon site conditions and the degree habitat improvement of pre-restoration site conditions.

  6. Macroinvertebrate communities evaluated prior to and following a channel restoration project in Silver Creek, Blaine County, Idaho, 2001-16

    Science.gov (United States)

    MacCoy, Dorene E.; Short, Terry M.

    2017-11-22

    The U.S. Geological Survey, in cooperation with Blaine County and The Nature Conservancy, evaluated the status of macroinvertebrate communities prior to and following a channel restoration project in Silver Creek, Blaine County, Idaho. The objective of the evaluation was to determine whether 2014 remediation efforts to restore natural channel conditions in an impounded area of Silver Creek caused declines in local macroinvertebrate communities. Starting in 2001 and ending in 2016, macroinvertebrates were sampled every 3 years at two long-term trend sites and sampled seasonally (spring, summer, and autumn) in 2013, 2015, and 2016 at seven synoptic sites. Trend-site communities were collected from natural stream-bottom substrates to represent locally established macroinvertebrate assemblages. Synoptic site communities were sampled using artificial (multi-plate) substrates to represent recently colonized (4–6 weeks) assemblages. Statistical summaries of spatial and temporal patterns in macroinvertebrate taxonomic composition at both trend and synoptic sites were completed.The potential effect of the restoration project on resident macroinvertebrate populations was determined by comparing the following community assemblage metrics:Total taxonomic richness (taxa richness);Total macroinvertebrate abundance (total abundance);Ephemeroptera, Plecoptera, Trichoptera (EPT) richness;EPT abundance;Simpson’s diversity; andSimpson’s evenness for periods prior to and following restoration.A significant decrease in one or more metric values in the period following stream channel restoration was the basis for determining impairment to the macroinvertebrate communities in Silver Creek.Comparison of pre-restoration (2001–13) and post‑restoration (2016) macroinvertebrate community composition at trend sites determined that no significant decreases occurred in any metric parameter for communities sampled in 2016. Taxa and EPT richness of colonized assemblages at synoptic sites

  7. Diversity and abundance of aquatic macroinvertebrates in a lotic environment in Midwestern São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Gabriel Lucas Bochini

    2009-04-01

    Full Text Available This study analyzed the diversity and abundance of an aquatic macroinvertebrate community in the Vargem Limpa stream located in Bauru, Midwestern São Paulo State, and characterized the water quality based on biological parameters. The sampling was carried out during the rain season (December, 2004. It was analyzed and identified 3,068 organisms belonging to 9 macroinvertebrate families. The system showed low richness and diversity of organisms in response to water quality.

  8. In situ effects of titanium dioxide nanoparticles on community structure of freshwater benthic macroinvertebrates.

    Science.gov (United States)

    Jovanović, Boris; Milošević, Djuradj; Piperac, Milica Stojković; Savić, Ana

    2016-06-01

    For the first time in the current literature, the effect of titanium dioxide (TiO2) nanoparticles on the community structure of macroinvertebrates has been investigated in situ. Macroinvertebrates were exposed for 100 days to an environmentally relevant concentration of TiO2 nanoparticles, 25 mg kg(-1) in sediment. Czekanowski's index was 0.61, meaning 39% of the macroinvertebrate community structure was affected by the TiO2 treatment. Non-metric multidimensional scaling (NMDS) visualized the qualitative and quantitative variability of macroinvertebrates at the community level among all samples. A distance-based permutational multivariate analysis of variance (PERMANOVA) revealed the significant effect of TiO2 on the macroinvertebrate community structure. The indicator value analysis showed that the relative frequency and abundance of Planorbarius corneus and Radix labiata were significantly lower in the TiO2 treatment than in the control. Meanwhile, Ceratopogonidae, showed a significantly higher relative frequency and abundance in the TiO2 treatment than in the control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Impact of heavy metals on macro-invertebrate fauna of the thaddo stream

    International Nuclear Information System (INIS)

    Nazneen, S.; Begum, F.; Sharmeen, R.; Ahmed, Z.

    2003-01-01

    Impact of some heavy metals like zinc, lead, copper, chromium and cadmium were studied at four spots on the macro-invertebrate fauna of the Thaddo stream, a tributary of Malir River. This was in correlation with an earlier study on the physico-chemical aspects of water which showed a severe pollution in this stream. Present data for the qualitative and quantitative analyses of macro-invertebrates and the ranges of heavy metals (Zn 0.5-3.5, Pb 0.90-1.42, Cu 0.35-0.93, Cr 0.0-0.08 and Cd 0.003-0.01 ppm) in the water samples also indicate high level of pollution in the stream. Macro-invertebrate fauna comprises only of aquatic insects which include larvae of Chironomus spp., adults of the Notonectus sp., and nymphs of Gomphus sp. (dragon fly) belonging to the order Diptera , Hemiptera and Odonata, respectively. Quantitatively Notonectus sp. predominated and followed by Chironomus larvae. The maximum concentrations of all heavy metals were recorded at spot 3. A general trend of increase was observed from up stream to down stream regions particularly in the level of zinc. However, a reverse trend was observed in the abundance of macro-invertebrates with a great reduction at spot 4. The statistical analysis of the data generally indicates a negative correlation between the values of the studied heavy metals and the abundance of macro-invertebrates throughout this study. (author)

  10. A Bayesian Method for Weighted Sampling

    OpenAIRE

    Lo, Albert Y.

    1993-01-01

    Bayesian statistical inference for sampling from weighted distribution models is studied. Small-sample Bayesian bootstrap clone (BBC) approximations to the posterior distribution are discussed. A second-order property for the BBC in unweighted i.i.d. sampling is given. A consequence is that BBC approximations to a posterior distribution of the mean and to the sampling distribution of the sample average, can be made asymptotically accurate by a proper choice of the random variables that genera...

  11. 40 CFR Appendix I to Part 261 - Representative Sampling Methods

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Representative Sampling Methods I...—Representative Sampling Methods The methods and equipment used for sampling waste materials will vary with the form and consistency of the waste materials to be sampled. Samples collected using the sampling...

  12. Reach-scale stream restoration in agricultural streams of southern Minnesota alters structural and functional responses of macroinvertebrates

    Science.gov (United States)

    Dolph, Christine L.; Eggert, Susan L.; Magner, Joe; Ferrington, Leonard C.; Vondracek, Bruce C.

    2015-01-01

    Recent studies suggest that stream restoration at the reach scale may not increase stream biodiversity, raising concerns about the utility of this conservation practice. We examined whether reach-scale restoration in disturbed agricultural streams was associated with changes in macroinvertebrate community structure (total macroinvertebrate taxon richness, total macroinvertebrate density, Ephemeroptera, Plecoptera, Trichoptera [EPT] taxon richness, % abundance of EPT taxa) or secondary production (macroinvertebrate biomass over time). We collected macroinvertebrate samples over the course of 1 y from restored and unrestored reaches of 3 streams in southern Minnesota and used generalized least-square (GLS) models to assess whether measures of community structure were related to reach type, stream site, or sampling month. After accounting for effects of stream site and time, we found no significant difference in total taxon richness or % abundance of EPT taxa between restored and unrestored reaches. However, the number of EPT taxa and macroinvertebrate density were significantly higher in restored than in unrestored reaches. We compared secondary production estimates among study reaches based on 95th-percentile confidence intervals generated via bootstrapping. In each study stream, secondary production was significantly (2–3×) higher in the restored than in the unrestored reach. Higher productivity in the restored reaches was largely a result of the disproportionate success of a few dominant, tolerant taxa. Our findings suggest that reach-scale restoration may have ecological effects that are not detected by measures of total taxon richness alone.

  13. Functional changes in littoral macroinvertebrate communities in response to watershed-level anthropogenic stress.

    Directory of Open Access Journals (Sweden)

    Katya E Kovalenko

    Full Text Available Watershed-scale anthropogenic stressors have profound effects on aquatic communities. Although several functional traits of stream macroinvertebrates change predictably in response to land development and urbanization, little is known about macroinvertebrate functional responses in lakes. We assessed functional community structure, functional diversity (Rao's quadratic entropy and voltinism in macroinvertebrate communities sampled across the full gradient of anthropogenic stress in Laurentian Great Lakes coastal wetlands. Functional diversity and voltinism significantly decreased with increasing development, whereas agriculture had smaller or non-significant effects. Functional community structure was affected by watershed-scale development, as demonstrated by an ordination analysis followed by regression. Because functional community structure affects energy flow and ecosystem function, and functional diversity is known to have important implications for ecosystem resilience to further environmental change, these results highlight the necessity of finding ways to remediate or at least ameliorate these effects.

  14. Log sampling methods and software for stand and landscape analyses.

    Science.gov (United States)

    Lisa J. Bate; Torolf R. Torgersen; Michael J. Wisdom; Edward O. Garton; Shawn C. Clabough

    2008-01-01

    We describe methods for efficient, accurate sampling of logs at landscape and stand scales to estimate density, total length, cover, volume, and weight. Our methods focus on optimizing the sampling effort by choosing an appropriate sampling method and transect length for specific forest conditions and objectives. Sampling methods include the line-intersect method and...

  15. Modeling Aquatic Macroinvertebrate Richness Using Landscape Attributes

    Directory of Open Access Journals (Sweden)

    Marcia S. Meixler

    2015-01-01

    Full Text Available We used a rapid, repeatable, and inexpensive geographic information system (GIS approach to predict aquatic macroinvertebrate family richness using the landscape attributes stream gradient, riparian forest cover, and water quality. Stream segments in the Allegheny River basin were classified into eight habitat classes using these three landscape attributes. Biological databases linking macroinvertebrate families with habitat classes were developed using life habits, feeding guilds, and water quality preferences and tolerances for each family. The biological databases provided a link between fauna and habitat enabling estimation of family composition in each habitat class and hence richness predictions for each stream segment. No difference was detected between field collected and modeled predictions of macroinvertebrate families in a paired t-test. Further, predicted stream gradient, riparian forest cover, and total phosphorus, total nitrogen, and suspended sediment classifications matched observed classifications much more often than by chance alone. High gradient streams with forested riparian zones and good water quality were predicted to have the greatest macroinvertebrate family richness and changes in water quality were predicted to have the greatest impact on richness. Our findings indicate that our model can provide meaningful landscape scale macroinvertebrate family richness predictions from widely available data for use in focusing conservation planning efforts.

  16. Water Quality Assessment Using Benthic Macroinvertebrates in Saigon River and Its Tributaries, Vietnam

    Directory of Open Access Journals (Sweden)

    Duc Pham Anh

    2016-06-01

    Full Text Available This study to enhance the discussion about the usefulness of benthic macroinvertebrates for water quality assessment in Saigon River and its tributaries. Data from 16 sites were used as a representative example for Saigon River and its tributaries in the area of basin over 4,500 km2, the length through provinces of Tay Ninh, Binh Phuoc, Binh Duong, and Ho Chi Minh City of about 280 km. The data covered the period of dry and rainy seasons in 2015, the survey sampled 16 sites (32 events of the Saigon River and its tributaries selected. To implement this evaluation, the analyses were based on MRC methods and classifications these improved by the scientific group.

  17. Effects of brine contamination from energy development on wetland macroinvertebrate community structure in the Prairie Pothole Region

    Science.gov (United States)

    Preston, Todd M.; Borgreen, Michael J.; Ray, Andrew M.

    2018-01-01

    Wetlands in the Prairie Pothole Region (PPR) of North America support macroinvertebrate communities that are integral to local food webs and important to breeding waterfowl. Macroinvertebrates in PPR wetlands are primarily generalists and well adapted to within and among year changes in water permanence and salinity. The Williston Basin, a major source of U.S. energy production, underlies the southwest portion of the PPR. Development of oil and gas results in the coproduction of large volumes of highly saline, sodium chloride dominated water (brine) and the introduction of brine can alter wetland salinity. To assess potential effects of brine contamination on macroinvertebrate communities, 155 PPR wetlands spanning a range of hydroperiods and salinities were sampled between 2014 and 2016. Brine contamination was documented in 34 wetlands with contaminated wetlands having significantly higher chloride concentrations, specific conductance and percent dominant taxa, and significantly lower taxonomic richness, Shannon diversity, and Pielou evenness scores compared to uncontaminated wetlands. Non-metric multidimensional scaling found significant correlations between several water quality parameters and macroinvertebrate communities. Chloride concentration and specific conductance, which can be elevated in naturally saline wetlands, but are also associated with brine contamination, had the strongest correlations. Five wetland groups were identified from cluster analysis with many of the highly contaminated wetlands located in a single cluster. Low or moderately contaminated wetlands were distributed among the remaining clusters and had macroinvertebrate communities similar to uncontaminated wetlands. While aggregate changes in macroinvertebrate community structure were observed with brine contamination, systematic changes were not evident, likely due to the strong and potentially confounding influence of hydroperiod and natural salinity. Therefore, despite the observed

  18. Statistical sampling methods for soils monitoring

    Science.gov (United States)

    Ann M. Abbott

    2010-01-01

    Development of the best sampling design to answer a research question should be an interactive venture between the land manager or researcher and statisticians, and is the result of answering various questions. A series of questions that can be asked to guide the researcher in making decisions that will arrive at an effective sampling plan are described, and a case...

  19. Biomonitoring with macroinvertebrate communities in Italy: What happened to our past and what is the future?

    Directory of Open Access Journals (Sweden)

    Tiziano Bo

    2016-10-01

    Full Text Available This paper reviews the history and development of biological water quality assessment using macroinvertebrates in Italy. Italy was one of the first European countries to officially adopt a biomonitoring system based on benthic invertebrates, the Indice Biotico Esteso (IBE. After the European Water Framework Directive (WFD 2000/60/EC, this method was replaced by the “Standardisation of River Classifications_Intercalibration Common Metrics” (STAR_ICM index, which met the new requirements. As this method has been employed for some years, it could be useful to take a provisional stock and to provide some suggestions to ameliorate the current biomonitoring approach, also trying to minimize the break with past practices and better harmonize the history of biomonitoring in Italy. One of the most evident difference between past and current approach is related to the amount of time and effort required in the application of the two methods. STAR_ICMi is a scientifically rigorous and modern method, but much more time-consuming and challenging in both field and laboratory efforts. This fact has various disturbing practical repercussions, i.e., the environmental agencies have generally reduced the number of sampling stations routinely monitored during the year. The aim of our work is to propose some operational changes that would help to simplify and expedite the monitoring process. In particular, regarding fieldwork, we focus on the time and effort required for macroinvertebrate collection, while for laboratory activity we suggest a reshaping of the requested taxonomic detail. Moreover, in this way the data provided by the new approach could be compared with the long time series available from the previous application of IBE.

  20. Evaluation of Sampling Methods for Bacillus Spore ...

    Science.gov (United States)

    Journal Article Following a wide area release of biological materials, mapping the extent of contamination is essential for orderly response and decontamination operations. HVAC filters process large volumes of air and therefore collect highly representative particulate samples in buildings. HVAC filter extraction may have great utility in rapidly estimating the extent of building contamination following a large-scale incident. However, until now, no studies have been conducted comparing the two most appropriate sampling approaches for HVAC filter materials: direct extraction and vacuum-based sampling.

  1. Assessing Ecosystem Integrity And Macroinvertebrates Community Structure Towards Conservation Of Small Streams In Tanzania

    Directory of Open Access Journals (Sweden)

    Fredrick Ojija

    2017-02-01

    Full Text Available This study attempts to use biological indices such as Biological Monitoring Working Party BMWP Average Score Per Taxa ASPT and Hilsenhoff Family Biotic Index FBI in order to determine the ecosystem health and water quality of Nzovwe stream in Mbeya Tanzania. Macroinvertebrates were sampled from Nzovwe stream using semi-quantitative techniques from March to June 2016. About 500 meters of Nzovwe stream was divided into 5 sampling sites each site was 100 meters apart. The macroinvertebrates were collected from all the possible microhabitats of each site using a 250m mesh size D- frame kick net. Macroinvertebrate specimens were preserved in the 70 ethyl alcohol in the polyethylene bottles. The samples were identified to the family level using standard identification keys. The BMWP score and ASPT score indicated good and moderate stream water quality respectively. The FBI showed the stream had possibility of some organic pollution. The Shannon-Wiener diversity index shows the sampling sites were moderately polluted or possibly impaired. Macroinvertebrates in pollution class II were abundant suggesting moderate pollution. Moreover the Midge Insects Diptera and Snail indicated the stream water quality or ecosystem health is between unimpaired and possibly impaired. Based on these results the study concludes that the stream ecosystem is moderately polluted and therefore the study recommends a regular stream monitoring.

  2. Small-sample-worth perturbation methods

    International Nuclear Information System (INIS)

    1985-01-01

    It has been assumed that the perturbed region, R/sub p/, is large enough so that: (1) even without a great deal of biasing there is a substantial probability that an average source-neutron will enter it; and (2) once having entered, the neutron is likely to make several collisions in R/sub p/ during its lifetime. Unfortunately neither assumption is valid for the typical configurations one encounters in small-sample-worth experiments. In such experiments one measures the reactivity change which is induced when a very small void in a critical assembly is filled with a sample of some test-material. Only a minute fraction of the fission-source neutrons ever gets into the sample and, of those neutrons that do, most emerge uncollided. Monte Carlo small-sample perturbations computations are described

  3. Effects of Management Legacies on Stream Fish and Aquatic Benthic Macroinvertebrate Assemblages

    Science.gov (United States)

    Quist, Michael C.; Schultz, Randall D.

    2014-09-01

    Fish and benthic macroinvertebrate assemblages often provide insight on ecological conditions for guiding management actions. Unfortunately, land use and management legacies can constrain the structure of biotic communities such that they fail to reflect habitat quality. The purpose of this study was to describe patterns in fish and benthic macroinvertebrate assemblage structure, and evaluate relationships between biota and habitat characteristics in the Chariton River system of south-central Iowa, a system likely influenced by various potential management legacies (e.g., dams, chemical removal of fishes). We sampled fishes, benthic macroinvertebrates, and physical habitat from a total of 38 stream reaches in the Chariton River watershed during 2002-2005. Fish and benthic macroinvertebrate assemblages were dominated by generalist species tolerant of poor habitat quality; assemblages failed to show any apparent patterns with regard to stream size or longitudinal location within the watershed. Metrics used to summarize fish assemblages and populations [e.g., presence-absence, relative abundance, Index of Biotic Integrity for fish (IBIF)] were not related to habitat characteristics, except that catch rates of piscivores were positively related to the depth and the amount of large wood. In contrast, family richness of benthic macroinvertebrates, richness of Ephemeroptera, Trichoptera, and Plecoptera taxa, and IBI values for benthic macroinvertebrates (IBIBM) were positively correlated with the amount of overhanging vegetation and inversely related to the percentage of fine substrate. A long history of habitat alteration by row-crop agriculture and management legacies associated with reservoir construction has likely resulted in a fish assemblage dominated by tolerant species. Intolerant and sensitive fish species have not recolonized streams due to downstream movement barriers (i.e., dams). In contrast, aquatic insect assemblages reflected aquatic habitat, particularly

  4. 19 CFR 151.70 - Method of sampling by Customs.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Method of sampling by Customs. 151.70 Section 151... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70 Method of sampling by Customs. A general sample shall be taken from each sampling unit, unless it is not...

  5. Non-indigenous macroinvertebrate species in Lithuanian fresh waters, Part 2: Macroinvertebrate assemblage deviation from naturalness in lotic systems and the consequent potential impacts on ecological quality assessment

    Directory of Open Access Journals (Sweden)

    Arbačiauskas K.

    2011-12-01

    Full Text Available The biological pressure represented by non-indigenous macroinvertebrate species (NIMS should be addressed in the implementation of EU Water Framework Directive as this can have a direct impact on the ’naturalness’ of the invaded macroinvertebrate assemblage. The biocontamination concept allows assessment of this deviation from naturalness, by evaluation of abundance and disparity contamination of an assemblage. This study aimed to assess the biocontamination of macroinvertebrate assemblages in Lithuanian rivers, thereby revealing the most high-impact non-indigenous species, and to explore the relationship between biocontamination and conventional metrics of ecological quality. Most of the studied rivers appeared to be impacted by NIMS. The amphipods Pontogammarus robustoides, Chelicorophium curvispinum and snail Litoglyphus naticoides were revealed as high-impact NIMS for Lithuanian lotic systems. Metrics of ecological quality which largely depend upon the richness of indicator taxa, such as the biological monitoring working party (BMWP score and Ephemeroptera/Plecoptera/Trichoptera (EPT taxa number, were negatively correlated with biocontamination, implying they could provide unreliable ecological quality estimates when NIMS are present. Routine macroinvertebrate water quality monitoring data are sufficient for generation of the biocontamination assessment and thus can provide supplementary information, with minimal extra expense or effort. We therefore recommend that biocontamination assessment is included alongside established methods for gauging biological and chemical water quality.

  6. Comparison of the abiotic preferences of macroinvertebrates in tropical river basins.

    Directory of Open Access Journals (Sweden)

    Gert Everaert

    Full Text Available We assessed and compared abiotic preferences of aquatic macroinvertebrates in three river basins located in Ecuador, Ethiopia and Vietnam. Upon using logistic regression models we analyzed the relationship between the probability of occurrence of five macroinvertebrate families, ranging from pollution tolerant to pollution sensitive, (Chironomidae, Baetidae, Hydroptilidae, Libellulidae and Leptophlebiidae and physical-chemical water quality conditions. Within the investigated physical-chemical ranges, nine out of twenty-five interaction effects were significant. Our analyses suggested river basin dependent associations between the macroinvertebrate families and the corresponding physical-chemical conditions. It was found that pollution tolerant families showed no clear abiotic preference and occurred at most sampling locations, i.e. Chironomidae were present in 91%, 84% and 93% of the samples taken in Ecuador, Ethiopia and Vietnam. Pollution sensitive families were strongly associated with dissolved oxygen and stream velocity, e.g. Leptophlebiidae were only present in 48%, 2% and 18% of the samples in Ecuador, Ethiopia and Vietnam. Despite some limitations in the study design, we concluded that associations between macroinvertebrates and abiotic conditions can be river basin-specific and hence are not automatically transferable across river basins in the tropics.

  7. Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

    Directory of Open Access Journals (Sweden)

    Miguel CAÑEDO-ARGÜELLES

    2009-08-01

    Full Text Available The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav. Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain following the method proposed by Kornijów & Kairesalo (1994. The aims of the study were to: 1 characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2 assess the contribution of elements of the epiphytic compartment to structuring the community; 3 define the optima and tolerances of selected epiphytic macroinvertebrate taxa for the most relevant ecological factors responsible for assemblage composition; and 4 identify possible epiphytic species assemblages that would allow a lagoon’s typology to be established, as well as their representative indicator species. Communities showed statistically significant seasonal variation, with two faunal peaks: one in summer, with high chironomid densities, and the other in winter, with high naidid densities. These peaks showed a clear response to the influence of environmental factors. Salinity explained the highest percentage of total variance (36%, while trophic variables (nutrients, phytoplanktonic chlorophyll-a, and total organic carbon and epiphyton biomass (19.2 and 4% of total variance explained, respectively were secondary. Three different epiphytic macroinvertebrate species assemblages could be defined. These assemblages were directly linked to conductivity conditions, which determined the rate of survival of certain taxa, and to the existence of a direct connection with the sea, which permitted the establishment of "brackish-water" species. In spite of the existence of these species assemblages, the species composition and biomass of epiphytic macroinvertebrates and epiphyton differed substantially between lagoons; both elements were subject to changes in the environment, which finally determined the site

  8. Perpendicular distance sampling: an alternative method for sampling downed coarse woody debris

    Science.gov (United States)

    Michael S. Williams; Jeffrey H. Gove

    2003-01-01

    Coarse woody debris (CWD) plays an important role in many forest ecosystem processes. In recent years, a number of new methods have been proposed to sample CWD. These methods select individual logs into the sample using some form of unequal probability sampling. One concern with most of these methods is the difficulty in estimating the volume of each log. A new method...

  9. Benthic macroinvertebrate assemblages in mangroves and open ...

    African Journals Online (AJOL)

    Benthic macroinvertebrate assemblages in mangroves and open intertidal areas on the Dar es Salaam coast, Tanzania. ... it is recommended that conservation efforts along the Tanzanian coast should focus here. Keywords: benthic macrofauna, community structure, littoral zone, Tanganyika, Western Indian Ocean ...

  10. Microplastic effect thresholds for freshwater benthic macroinvertebrates

    NARCIS (Netherlands)

    Redondo Hasselerharm, P.E.; Dede Falahudin, Dede; Peeters, E.T.H.M.; Koelmans, A.A.

    2018-01-01

    Now that microplastics have been detected in lakes, rivers and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates

  11. Aquatic macroinvertebrates and water quality of Sandia Canyon, Los Alamos National Laboratory, November 1993--October 1994

    Energy Technology Data Exchange (ETDEWEB)

    Cross, S.

    1995-08-01

    The Ecological Studies Team (EST) of ESH-20 at Los Alamos National Laboratory (LANL) has collected samples from the stream within Sandia Canyon since the summer of 1990. These field studies gather water quality measurements and collect aquatic macroinvertebrates from permanent sampling sites. Reports by Bennett (1994) and Cross (1994) discuss previous EST aquatic studies in Sandia Canyon. This report updates and expands those findings. EST collected water quality data and aquatic macroinvertebrates at five permanent stations within the canyon from November 1993 through October 1994. The two upstream stations are located below outfalls that discharge industrial and sanitary waste effluent into the stream, thereby maintaining year-round flow. Some water quality parameters are different at the first three stations from those expected of natural streams in the area, indicating degraded water quality due to effluent discharges. The aquatic habitat at the upper stations has also been degraded by sedimentation and channelization. The macroinvertebrate communities at these stations are characterized by low diversities and unstable communities. In contrast, the two downstream stations appear to be in a zone of recovery, where water quality parameters more closely resemble those found in natural streams of the area. The two lower stations have increased macroinvertebrate diversity and stable communities, further indications of downstream water quality improvement.

  12. Risk assessment of imidacloprid use in forest settings on the aquatic macroinvertebrate community.

    Science.gov (United States)

    Benton, Elizabeth P; Grant, Jerome F; Nichols, Rebecca J; Webster, R Jesse; Schwartz, John S; Bailey, Joseph K

    2017-11-01

    The isolated effects of a single insecticide can be difficult to assess in natural settings because of the presence of numerous pollutants in many watersheds. Imidacloprid use for suppressing hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae), in forests offers a rare opportunity to assess potential impacts on aquatic macroinvertebrates in relatively pristine landscapes. Aquatic macroinvertebrate communities were assessed in 9 streams in Great Smoky Mountains National Park (southern Appalachian Mountains, USA). The streams flow through hemlock conservation areas where imidacloprid soil drench treatments were applied for hemlock woolly adelgid suppression. Sites were located upstream and downstream of the imidacloprid treatments. Baseline species presence data (pre-imidacloprid treatment) were available from previous sample collections at downstream sites. Downstream and upstream sites did not vary in numerous community measures. Although comparisons of paired upstream and downstream sites showed differences in diversity in 7 streams, higher diversity was found more often in downstream sites. Macroinvertebrate functional feeding groups and life habits were similar between downstream and upstream sites. Downstream and baseline stream samples were similar. While some functional feeding group and life habit species richness categories varied, variations did not indicate poorer quality downstream communities. Imidacloprid treatments applied according to US Environmental Protection Agency federal restrictions did not result in negative effects to aquatic macroinvertebrate communities, which indicates that risks of imidacloprid use in forest settings are low. Environ Toxicol Chem 2017;36:3108-3119. © 2017 SETAC. © 2017 SETAC.

  13. Biodiversity of benthic macroinvertebrates in Air Terjun Asahan, Asahan, Melaka, Malaysia

    Science.gov (United States)

    Nurhafizah-Azwa, S.; Ahmad A., K.

    2016-11-01

    A study on benthic macroinvertebrate diversity was conducted at Air Terjun Asahan, Asahan, Melaka. Five stations were selected with distance intervals of approximately 500 metres. Three replicates of benthic macroinvertebrate and water samples were taken. Results classified Air Terjun Asahan in class II, which indicated good water quality based on WQI recommended by the Department of Environment. A total of 1 phylum, 2 classes, 6 order, 30 families, and 2183 individuals were successfully sampled and recorded. The analysis showed that the average value of Shannon Diversity Index, H' (2.19), Pielou Evenness Index, J' (0.30), and Margaleff Richness Index, DMG (3.77) described that Air Terjun Asahan was in moderate condition and the distribution of macroinvertebrates was uniform between stations. Correlation test showed that the WQI had a strong relationship with the diversity indices involved. BMWP, and FBI showed that Air Terjun Asahan was in good water quality. CCA test was conducted to show environmental factors towards benthic macroinvertebrate distribution. The presence of Leptophlebiidae, Baetidae, Heptageniidae and Chironomidae with high abundance of the families showed the potential as biological indicators of a clean ecosystem.

  14. Contribution of trace metals in structuring in situ macroinvertebrate community composition along a salinity gradient

    NARCIS (Netherlands)

    Peeters, E.T.H.M.; Gardeniers, J.J.P.; Koelmans, A.A.

    2000-01-01

    Macroinvertebrates were studied along a salinity gradient in the North Sea Canal, The Netherlands, to quantify the effect of trace metals (cadmium, copper, lead, zinc) on community composition. In addition, two methods for assessing metal bioavailability (normalizing metal concentrations on organic

  15. Studying the movement behaviour of benthic macroinvertebrates with automated video tracking

    NARCIS (Netherlands)

    Augusiak, J.A.; Brink, van den P.J.

    2015-01-01

    Quantifying and understanding movement is critical for a wide range of questions in basic and applied ecology. Movement ecology is also fostered by technological advances that allow automated tracking for a wide range of animal species. However, for aquatic macroinvertebrates, such detailed methods

  16. Influence of riparian canopy on macroinvertebrate composition and food habits of juvenile salmonids in several Oregon streams.

    Science.gov (United States)

    William R. Meehan

    1996-01-01

    The community composition of macroinvertebrates and the feeding habits of juvenile salmonids were studied in eight Oregon streams. Benthic, drift, sticky trap, and water trap samples were taken over a 3-year period, along with stomach samples of the fish. Samples were taken in stream reaches with and without riparian canopy. Both main effects—fish diet versus...

  17. Spatial and temporal heterogeneity in a subtropical reservoir and their effects over the benthic macroinvertebrate community

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme de Souza Beghelli

    2014-09-01

    Full Text Available AIM: The objective of the present study was to demonstrate the influences of the environment spatial heterogeneity on benthic macroinvertebrates considering transverse and longitudinal gradients as also seasonality. METHODS: Four samplings were performed: two in the wet and two in the dry season in the riverine, transitional and lacustrine zones in the littoral and profundal regions of Itupararanga reservoir, SP, Brazil. Abiotic characterization of the water and of the sediment was performed. The biotic characterization was based on richness, dominance, diversity, and density of organisms, as well as on the relative abundance of predominant taxa. Two-way ANOSIM analyses were performed for both biotic and abiotic components, in order to test the significance of the differences in the longitudinal and transverse directions as well as of the differences between seasons. RESULTS: Compartmentalization was present in both directions, longitudinal and transverse. In a general way, the littoral region presented higher diversity values when compared with the profundal region, and the riverine zone presented high densities and high percentage of taxons, which usually indicate organic pollution. The differentiation between the transitional and lacustrine zones was determined mainly by taxonomic composition. Seasonality was also observed and the transportation of small particles, the entrance of nutrients, and the presence of macrophytes were considered as determinants for differentiation. CONCLUSIONS: Together, these results demonstrate the responses of benthic macroinvertebrate communities considering distinct sources of variation: longitudinal heterogeneity, determined by the increasing distance from the forming rivers that leads to a gradient of physical and chemical conditions; transverse heterogeneity, determined by the proximity with the land environment and depth differences. Seasonal heterogeneity was recorded during the period of this research and

  18. Community-level response of fishes and aquatic macroinvertebrates to stream restoration in a third-order tributary of the Potomac River, USA

    Science.gov (United States)

    Selego, Stephen M.; Rose, Charnee L.; Merovich, George T.; Welsh, Stuart A.; Anderson, James T.

    2012-01-01

    Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010). Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI), the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions.

  19. Community-Level Response of Fishes and Aquatic Macroinvertebrates to Stream Restoration in a Third-Order Tributary of the Potomac River, USA

    Directory of Open Access Journals (Sweden)

    Stephen M. Selego

    2012-01-01

    Full Text Available Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010. Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI, the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions.

  20. Change does not happen overnight: a case study on stream macroinvertebrates

    Directory of Open Access Journals (Sweden)

    Guareschi S.

    2016-01-01

    Full Text Available The influence of day/night conditions on individual animal/plant species has been widely studied, but diel cycle studies of the entire stream macroinvertebrate community are extremely rare. This study explored potential dissimilarities between daytime and nighttime macroinvertebrate assemblages by extensive fieldwork conducted in the Lemme stream, a natural water course of NW Italy. Here numerous structural and functional metrics (richness, abundance, biomass, indicator taxa, composition, biomonitoring values and feeding groups were evaluated at the family level. Small-scale environmental variables were investigated to understand possible differences between macroinvertebrate assemblages in the daytime/nighttime. After collecting and identifying 21 459 organisms of 50 taxa, Chironomidae (Diptera was the most abundant under both day and night conditions. Our findings stressed that similar results and biological information on daytime/nighttime data were obtained. No marked differences could be related to various factors: heterotrophic condition of small-order streams, presence of aquatic predators under night and day conditions, absence of taxa with a specific phototaxis. Of all the environmental variables, velocity was always the most important in both situations, with some differences detected in the importance of the second variable (riverbed substrate diameter. This research, and future studies on different conditions and geographic areas, will contribute knowledge on stream macroinvertebrate diel activity, and provide useful information about efficient sampling strategies.

  1. Concordance between macrophytes and macroinvertebrates in a Mediterranean river of central Apennine region.

    Science.gov (United States)

    Traversetti, Lorenzo; Scalici, Massimiliano; Ginepri, Valeria; Manfrin, Alessandro; Ceschin, Simona

    2014-05-01

    The main aim of this study was to improve the knowledge about the concordance among macrophytes and macroinvertebrates to provide complementary information and facilitate the procedures for quality assessment of river ecosystems. Macrophytes and macroinvertebrates were collected in 11 sampling sites along a central Apennine calcareous river in October 2008 and June 2009. The concordance between the two biomonitoring groups was tested according to several environmental parameters. The comparison of data matrix similarities by Mantel test showed differences in the assemblage of macrophytes and macroinvertebrates along the river since correlation values were 0.04, p > 0.05 in October 2008 and 0.39, p > 0.05 in June 2009. The study revealed lack of concordance between the two groups, emphasizing that the information provided by macrophytes and macroinvertebrates does not overlap in terms of response to environmental parameters. Indeed, the two different biological groups resulted useful descriptors of different parameters. Together, they could represent a complementary tool to reflect the river environmental quality.

  2. Land Use Influences Niche Size and the Assimilation of Resources by Benthic Macroinvertebrates in Tropical Headwater Streams.

    Directory of Open Access Journals (Sweden)

    Diego Marcel Parreira de Castro

    Full Text Available It is well recognized that assemblage structure of stream macroinvertebrates changes with alterations in catchment or local land use. Our objective was to understand how the trophic ecology of benthic macroinvertebrate assemblages responds to land use changes in tropical streams. We used the isotope methodology to assess how energy flow and trophic relations among macroinvertebrates were affected in environments affected by different land uses (natural cover, pasture, sugar cane plantation. Macroinvertebrates were sampled and categorized into functional feeding groups, and available trophic resources were sampled and evaluated for the isotopic composition of 13C and 15N along streams located in the Cerrado (neotropical savanna. Streams altered by pasture or sugar cane had wider and more overlapped trophic niches, which corresponded to more generalist feeding habits. In contrast, trophic groups in streams with native vegetation had narrower trophic niches with smaller overlaps, suggesting greater specialization. Pasture sites had greater ranges of resources exploited, indicating higher trophic diversity than sites with natural cover and sugar cane plantation. We conclude that agricultural land uses appears to alter the food base and shift macroinvertebrate assemblages towards more generalist feeding behaviors and greater overlap of the trophic niches.

  3. Downstream effects of hydropower production on aquatic macroinvertebrate assemblages in two rivers in Costa Rica.

    Science.gov (United States)

    Chaves-Ulloa, Ramsa; Umaña-Villalobos, Gerardo; Springer, Monika

    2014-04-01

    Despite the fact that little is known about the consequences of hydropower production in tropical areas, many large dams (> 15 m high) are currently under construction or consideration in the tropics. We researched the effects of large hydroelectric dams on aquatic macroinvertebrate assemblages in two Costa Rican rivers. We measured physicochemical characteristics and sampled aquatic macroinvertebrates from March 2003 to March 2004 in two dammed rivers, Peñas Blancas and San Lorenzo, as well as in the undammed Chachagua River. Sites above and below the dam had differences in their physicochemical variables, with wide variation and extreme values in variables measured below the dam in the San Lorenzo River. Sites below the dams had reduced water discharges, velocities, and depths when compared with sites above the dams, as well as higher temperatures and conductivity. Sites above dams were dominated by collector-gatherer-scrapers and habitat groups dominated by swimmer-clingers, while sites below dams had a more even representation of groups. In contrast, a comparison between two sites at different elevation in the undammed river maintained a similar assemblage composition. Tributaries might facilitate macroinvertebrate recovery above the turbine house, but the assemblage below the turbine house resembled the one below the dam. A massive sediment release event from the dam decreased the abundance per sample and macroinvertebrate taxa below the dam in the Peñas Blancas River. Our study illustrates the effects of hydropower production on neotropical rivers, highlighting the importance of using multiple measures of macroinvertebrate assemblage structure for assessing this type of environmental impact.

  4. On Angular Sampling Methods for 3-D Spatial Channel Models

    DEFF Research Database (Denmark)

    Fan, Wei; Jämsä, Tommi; Nielsen, Jesper Ødum

    2015-01-01

    This paper discusses generating three dimensional (3D) spatial channel models with emphasis on the angular sampling methods. Three angular sampling methods, i.e. modified uniform power sampling, modified uniform angular sampling, and random pairing methods are proposed and investigated in detail....... The random pairing method, which uses only twenty sinusoids in the ray-based model for generating the channels, presents good results if the spatial channel cluster is with a small elevation angle spread. For spatial clusters with large elevation angle spreads, however, the random pairing method would fail...... and the other two methods should be considered....

  5. Sampling Methods for Wallenius' and Fisher's Noncentral Hypergeometric Distributions

    DEFF Research Database (Denmark)

    Fog, Agner

    2008-01-01

    the mode, ratio-of-uniforms rejection method, and rejection by sampling in the tau domain. Methods for the multivariate distributions include: simulation of urn experiments, conditional method, Gibbs sampling, and Metropolis-Hastings sampling. These methods are useful for Monte Carlo simulation of models...... of biased sampling and models of evolution and for calculating moments and quantiles of the distributions.......Several methods for generating variates with univariate and multivariate Wallenius' and Fisher's noncentral hypergeometric distributions are developed. Methods for the univariate distributions include: simulation of urn experiments, inversion by binary search, inversion by chop-down search from...

  6. Some connections between importance sampling and enhanced sampling methods in molecular dynamics.

    Science.gov (United States)

    Lie, H C; Quer, J

    2017-11-21

    In molecular dynamics, enhanced sampling methods enable the collection of better statistics of rare events from a reference or target distribution. We show that a large class of these methods is based on the idea of importance sampling from mathematical statistics. We illustrate this connection by comparing the Hartmann-Schütte method for rare event simulation (J. Stat. Mech. Theor. Exp. 2012, P11004) and the Valsson-Parrinello method of variationally enhanced sampling [Phys. Rev. Lett. 113, 090601 (2014)]. We use this connection in order to discuss how recent results from the Monte Carlo methods literature can guide the development of enhanced sampling methods.

  7. A Europe-wide system for assessing the quality of rivers using macroinvertebrates: the AQEM Project* and its importance for southern Europe (with special emphasis on Italy

    Directory of Open Access Journals (Sweden)

    Joanna L. KEMP

    2001-09-01

    Full Text Available The AQEM Project aims to develop a Europe-wide system for monitoring the ecological quality of rivers using macroinvertebrates, to satisfy the requirements of the EU Water Framework Directive. Three main types of anthropogenic perturbation are being investigated: morphological degradation, water (organic pollution and acidification (the last is not under investigation in Italy. The selection of reference and impaired study sites is discussed. Particular attention is paid to the problems encountered when defining reference conditions. The initial stages of the project highlighted the lack of a Europe-wide definition of river types. The future development of such a typology from the AQEM database is discussed. The standard AQEM data gathering methods are presented, from background information about sites to the microhabitat-based macroinvertebrate sampling method. The extended fieldwork methods used in Italy are described. These included the separate analysis of the invertebrate assemblages from each replicate, the recording of additional microhabitat variables for each replicate and the completion of large-scale survey techniques for each site (including RHS. The extended method was designed to enhance the important ecological information available from the dataset, particularly relevant in Italy where significant gaps exist in the taxonomic and ecological knowledge of many macroinvertebrate taxa. Preliminary and expected findings are presented, including examples of the range and habitat selection of two species of Ephemeroptera endemic to Italy, as well as data relating to the number of taxa found at a site with increasing numbers of microhabitat replicates taken. The importance of the AQEM Project not only for biomonitoring, but also for ecology, taxonomy and conservation, in Italy and for the south of Europe in general, is emphasised.

  8. Sampling Methods in Cardiovascular Nursing Research: An Overview.

    Science.gov (United States)

    Kandola, Damanpreet; Banner, Davina; O'Keefe-McCarthy, Sheila; Jassal, Debbie

    2014-01-01

    Cardiovascular nursing research covers a wide array of topics from health services to psychosocial patient experiences. The selection of specific participant samples is an important part of the research design and process. The sampling strategy employed is of utmost importance to ensure that a representative sample of participants is chosen. There are two main categories of sampling methods: probability and non-probability. Probability sampling is the random selection of elements from the population, where each element of the population has an equal and independent chance of being included in the sample. There are five main types of probability sampling including simple random sampling, systematic sampling, stratified sampling, cluster sampling, and multi-stage sampling. Non-probability sampling methods are those in which elements are chosen through non-random methods for inclusion into the research study and include convenience sampling, purposive sampling, and snowball sampling. Each approach offers distinct advantages and disadvantages and must be considered critically. In this research column, we provide an introduction to these key sampling techniques and draw on examples from the cardiovascular research. Understanding the differences in sampling techniques may aid nurses in effective appraisal of research literature and provide a reference pointfor nurses who engage in cardiovascular research.

  9. 19 CFR 151.83 - Method of sampling.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Method of sampling. 151.83 Section 151.83 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Cotton § 151.83 Method of sampling. For...

  10. 7 CFR 29.110 - Method of sampling.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Method of sampling. 29.110 Section 29.110 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Inspectors, Samplers, and Weighers § 29.110 Method of sampling. In sampling tobacco...

  11. Temporally variable macroinvertebrate-stone relationships in streams

    DEFF Research Database (Denmark)

    Jacobsen, D.

    2005-01-01

    of fauna parameter and stone variable from different sampling dates (n=9-11) were rarely correlated to any of the measures of stream stability, this study has demonstrated high temporal variability in fauna-stone relationships (CV's of regression slopes). Consequently, temporally un-replicated studies......Stones were used to sample macroinvertebrates and characterise microhabitats at monthly or bimonthly intervals in six Ecuadorian streams covering a gradient in four different stability measures and other stream characteristics. The physical variables current velocity, water depth, horizontal...... of families vs. individuals) were related to the physical characteristics of individual stone habitats. My second objective was to quantify temporal variability in fauna-stone relationships and to analyse if such variability was related to overall stability of stream reaches. Partial Least Squares (PLS...

  12. Macroinvertebrate assemblages in agricultural, mining, and urban tropical streams: implications for conservation and management.

    Science.gov (United States)

    Mwedzi, Tongayi; Bere, Taurai; Mangadze, Tinotenda

    2016-06-01

    The study evaluated the response of macroinvertebrate assemblages to changes in water quality in different land-use settings in Manyame catchment, Zimbabwe. Four land-use categories were identified: forested commercial farming, communal farming, Great Dyke mining (GDM) and urban areas. Macroinvertebrate community structure and physicochemical variables data were collected in two seasons from 41 sites following standard methods. Although not environmentally threatening, urban and GDM areas were characterised by higher conductivity, total dissolved solids, salinity, magnesium and hardness. Chlorides, total phosphates, total nitrogen, calcium, potassium and sodium were significantly highest in urban sites whilst dissolved oxygen (DO) was significantly higher in the forested commercial faming and GDM sites. Macroinvertebrate communities followed the observed changes in water quality. Macroinvertebrates in urban sites indicated severe pollution (e.g. Chironomidae) whilst those in forested commercial farming sites and GDM sites indicated relatively clean water (e.g. Notonemouridae). Forested watersheds together with good farm management practices are important in mitigating impacts of urbanisation and agriculture. Strategies that reduce oxygen-depleting substances must be devised to protect the health of Zimbabwean streams. The study affirms the wider applicability of the South African Scoring System in different land uses.

  13. Variance in water chemistry parameters in isolated wetlands of Florida, USA, and relationships with macroinvertebrate and diatom community structure

    Science.gov (United States)

    Eighty small isolated wetlands throughout Florida were sampled in 2005 to explore within-site variability of water chemistry parameters and relate water chemistry to macroinvertebrate and diatom community structure. Three samples or measures of water were collected within each si...

  14. Bioassessment tools in novel habitats: an evaluation of indices and sampling methods in low-gradient streams in California.

    Science.gov (United States)

    Mazor, Raphael D; Schiff, Kenneth; Ritter, Kerry; Rehn, Andy; Ode, Peter

    2010-08-01

    Biomonitoring programs are often required to assess streams for which assessment tools have not been developed. For example, low-gradient streams (slopeindices in the state were developed in high-gradient systems. This study evaluated the performance of three sampling methods [targeted riffle composite (TRC), reach-wide benthos (RWB), and the margin-center-margin modification of RWB (MCM)] and two indices [the Southern California Index of Biotic Integrity (SCIBI) and the ratio of observed to expected taxa (O/E)] in low-gradient streams in California for application in this habitat type. Performance was evaluated in terms of efficacy (i.e., ability to collect enough individuals for index calculation), comparability (i.e., similarity of assemblages and index scores), sensitivity (i.e., responsiveness to disturbance), and precision (i.e., ability to detect small differences in index scores). The sampling methods varied in the degree to which they targeted macroinvertebrate-rich microhabitats, such as riffles and vegetated margins, which may be naturally scarce in low-gradient streams. The RWB method failed to collect sufficient numbers of individuals (i.e., >or=450) to calculate the SCIBI in 28 of 45 samples and often collected fewer than 100 individuals, suggesting it is inappropriate for low-gradient streams in California; failures for the other methods were less common (TRC, 16 samples; MCM, 11 samples). Within-site precision, measured as the minimum detectable difference (MDD) was poor but similar across methods for the SCIBI (ranging from 19 to 22). However, RWB had the lowest MDD for O/E scores (0.20 versus 0.24 and 0.28 for MCM and TRC, respectively). Mantel correlations showed that assemblages were more similar within sites among methods than within methods among sites, suggesting that the sampling methods were collecting similar assemblages of organisms. Statistically significant disagreements among methods were not detected, although O/E scores were higher

  15. Validation of EIA sampling methods - bacterial and biochemical analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Sheelu, G.; LokaBharathi, P.A.; Nair, S.; Raghukumar, C.; Mohandass, C.

    to temporal factors. Paired T-test between pre- and post-disturbance samples suggested that the above methods of sampling and variables like TC, protein and TOC could be used for monitoring disturbance....

  16. New adaptive sampling method in particle image velocimetry

    International Nuclear Information System (INIS)

    Yu, Kaikai; Xu, Jinglei; Tang, Lan; Mo, Jianwei

    2015-01-01

    This study proposes a new adaptive method to enable the number of interrogation windows and their positions in a particle image velocimetry (PIV) image interrogation algorithm to become self-adapted according to the seeding density. The proposed method can relax the constraint of uniform sampling rate and uniform window size commonly adopted in the traditional PIV algorithm. In addition, the positions of the sampling points are redistributed on the basis of the spring force generated by the sampling points. The advantages include control of the number of interrogation windows according to the local seeding density and smoother distribution of sampling points. The reliability of the adaptive sampling method is illustrated by processing synthetic and experimental images. The synthetic example attests to the advantages of the sampling method. Compared with that of the uniform interrogation technique in the experimental application, the spatial resolution is locally enhanced when using the proposed sampling method. (technical design note)

  17. Altitudinal distribution limits of aquatic macroinvertebrates

    DEFF Research Database (Denmark)

    Madsen, Philip B.; Morabowen, Andrés; Andino, Patricio

    2015-01-01

    1. Temperature and oxygen are recognised as the main drivers of altitudinal limits of species distributions. However, the two factors are linked, and both decrease with altitude, why their effects are difficult to disentangle. 2. This was experimentally addressed using aquatic macroinvertebrates...... relatively small differences in temperature and oxygen may produce effects explaining ecological patterns, and depending on the taxon, either water temperature or oxygen saturation, without clear interacting effects, are important drivers of altitudinal limits....

  18. A flexible method for multi-level sample size determination

    International Nuclear Information System (INIS)

    Lu, Ming-Shih; Sanborn, J.B.; Teichmann, T.

    1997-01-01

    This paper gives a flexible method to determine sample sizes for both systematic and random error models (this pertains to sampling problems in nuclear safeguard questions). In addition, the method allows different attribute rejection limits. The new method could assist achieving a higher detection probability and enhance inspection effectiveness

  19. Promoting a functional macroinvertebrate approach in the biomonitoring of Italian lotic systems

    Directory of Open Access Journals (Sweden)

    Richard W. Merritt

    2016-06-01

    Full Text Available Over fifty years of research on freshwater macroinvertebrates has been driven largely by the state of the taxonomy of these organisms. Significant advances have been and continue to be made in developing ever more refined keys to macroinvertebrate groups. When advances in macroinvertebrate ecological research are restricted by the level of detail in identifications, then analysis by function is a viable alternative. The focus on function, namely adaptations of macroinvertebrates to habitats and the utilization of food resources, has facilitated ecological evaluation of freshwater ecosystems. This classification is based not on what insects eat, but how they obtain their food. These categories are called 'functional feeding groups', as the name implies, denoting their functional role when describing how and where they feed. This is the basis for the functional feeding group (FFG method that was initially developed in the early 1960s. Taxonomy is applied only to the level of detail that allows assignment to one of five functional feeding group categories: detrital shredders, scrapers, filtering collectors, gatherers, and predators. The aim of this short communication, originating from the presentation of R.W. Merritt at the Biomonitoring Symposium in Rome, 2015, is to promote the use of a functional approach in biomonitoring, especially in Italian and European lotic systems. Here, we present two case studies and we discuss the advantages of the method, especially considering the great availability of quantitative data on macroinvertebrates after the implementation of the WFD 2000/60. We are confident that the increase of functional assessment of ecosystem attributes could have important and direct repercussions in the understanding and management of running waters.

  20. Effects of sediment quality on macroinvertebrates in the Sunraysia region of the Murray-Darling Rivers, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Sharley, David J. [Centre for Environmental Stress and Adaptation Research-Hoffmann Laboratory, Zoology Department, University of Melbourne, Level 2, Bio 21 Institute, 30 Flemington Road, Parkville, Victoria 3010 (Australia)], E-mail: sharleyd@unimelb.edu.au; Hoffmann, Ary A. [Centre for Environmental Stress and Adaptation Research-Hoffmann Laboratory, Zoology Department, University of Melbourne, Level 2, Bio 21 Institute, 30 Flemington Road, Parkville, Victoria 3010 (Australia); Pettigrove, Vincent [Research and Technology, Melbourne Water, PO Box 4342, Melbourne, Victoria 3001 (Australia)

    2008-12-15

    A field-based microcosm approach was tested to identify deterioration of sediment quality in waterways using freshwater macroinvertebrates. The method can potentially identify the nature of contaminants based on species-specific responses. Sediments were collected from the Murray and Darling Rivers and irrigation drains within the Sunraysia region of south-eastern Australia and compared to non-polluted reference sediment. Clean sediments were also spiked with fertiliser to test whether nutrients affected the aquatic fauna. Seven of the eight sediments from the Sunraysia region had a negative impact on the macroinvertebrates, in particular sediment from the Darling River, which supported an impoverished fauna. Three species of chironomid showed varied responses to sediment quality and, although it was hypothesised that nutrients may have impacted on the macroinvertebrate fauna, the results suggest that other pollutants are also involved. The field-based microcosm method proved effective for determining the impact of sediment quality on indigenous macroinvertebrates. - Sediment quality effects on freshwater macroinvertebrates are isolated.

  1. Effects of sediment quality on macroinvertebrates in the Sunraysia region of the Murray-Darling Rivers, Australia

    International Nuclear Information System (INIS)

    Sharley, David J.; Hoffmann, Ary A.; Pettigrove, Vincent

    2008-01-01

    A field-based microcosm approach was tested to identify deterioration of sediment quality in waterways using freshwater macroinvertebrates. The method can potentially identify the nature of contaminants based on species-specific responses. Sediments were collected from the Murray and Darling Rivers and irrigation drains within the Sunraysia region of south-eastern Australia and compared to non-polluted reference sediment. Clean sediments were also spiked with fertiliser to test whether nutrients affected the aquatic fauna. Seven of the eight sediments from the Sunraysia region had a negative impact on the macroinvertebrates, in particular sediment from the Darling River, which supported an impoverished fauna. Three species of chironomid showed varied responses to sediment quality and, although it was hypothesised that nutrients may have impacted on the macroinvertebrate fauna, the results suggest that other pollutants are also involved. The field-based microcosm method proved effective for determining the impact of sediment quality on indigenous macroinvertebrates. - Sediment quality effects on freshwater macroinvertebrates are isolated

  2. Systems and methods for self-synchronized digital sampling

    Science.gov (United States)

    Samson, Jr., John R. (Inventor)

    2008-01-01

    Systems and methods for self-synchronized data sampling are provided. In one embodiment, a system for capturing synchronous data samples is provided. The system includes an analog to digital converter adapted to capture signals from one or more sensors and convert the signals into a stream of digital data samples at a sampling frequency determined by a sampling control signal; and a synchronizer coupled to the analog to digital converter and adapted to receive a rotational frequency signal from a rotating machine, wherein the synchronizer is further adapted to generate the sampling control signal, and wherein the sampling control signal is based on the rotational frequency signal.

  3. Increased concentrations of polycyclic aromatic hydrocarbons in Alpine streams during annual snowmelt: investigating effects of sampling method, site characteristics, and meteorology.

    Science.gov (United States)

    Shahpoury, Pourya; Hageman, Kimberly J; Matthaei, Christoph D; Alumbaugh, Robert E; Cook, Michelle E

    2014-10-07

    Silicone passive samplers and macroinvertebrates were used to measure time-integrated concentrations of polycyclic aromatic hydrocarbons (PAHs) in alpine streams during annual snowmelt. The three sampling sites were located near a main highway in Arthur's Pass National Park in the Southern Alps of New Zealand. A similar set of PAH congeners, composed of 2-4 rings, were found in silicone passive samplers and macroinvertebrates. The background PAH concentrations were similar at all sites, implying that proximity to the highway did not affect concentrations. In passive samplers, an increase of PAH concentrations by up to seven times was observed during snowmelt. In macroinvertebrates, the concentration changes were moderate; however, macroinvertebrate sampling did not occur during the main pulse observed in the passive samplers. The extent of vegetation in the catchment appeared to affect the concentration patterns seen at the different stream sites. A strong correlation was found between PAH concentrations in passive samplers and the amount of rainfall in the study area, indicating that the washout of contaminants from snowpack by rainfall was an important process.

  4. DOE methods for evaluating environmental and waste management samples

    International Nuclear Information System (INIS)

    Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

    1993-03-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) provides applicable methods in use by. the US Department of Energy (DOE) laboratories for sampling and analyzing constituents of waste and environmental samples. The development of DOE Methods is supported by the Laboratory Management Division (LMD) of the DOE. This document contains chapters and methods that are proposed for use in evaluating components of DOE environmental and waste management samples. DOE Methods is a resource intended to support sampling and analytical activities that will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the US Environmental Protection Agency (EPA), or others

  5. DOE methods for evaluating environmental and waste management samples.

    Energy Technology Data Exchange (ETDEWEB)

    Goheen, S C; McCulloch, M; Thomas, B L; Riley, R G; Sklarew, D S; Mong, G M; Fadeff, S K [eds.; Pacific Northwest Lab., Richland, WA (United States)

    1994-04-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) provides applicable methods in use by. the US Department of Energy (DOE) laboratories for sampling and analyzing constituents of waste and environmental samples. The development of DOE Methods is supported by the Laboratory Management Division (LMD) of the DOE. This document contains chapters and methods that are proposed for use in evaluating components of DOE environmental and waste management samples. DOE Methods is a resource intended to support sampling and analytical activities that will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the US Environmental Protection Agency (EPA), or others.

  6. Aquatic macroinvertebrates of Batalha river reservoir for water captation and supply of the city of Bauru, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Diana Calcidoni Moreira

    2009-08-01

    Full Text Available In this study the composition and diversity of aquatic macroinvertebrates were evaluated in the reservoir of water captation of Batalha river for treatment and supplying of the city of Bauru. The samples were collected in dry (from June to August, 2005 and rainy (from December, 2005 to February, 2006 seasons. We analyzed and identified 840 organisms belonging to 8 taxa in dry season and 4 taxa in rainy season. The system presented low abundance and diversity of macroinvertebrates probably due to the water quality and its physical and chemical variations associated with rain events.

  7. Sampling methods for amphibians in streams in the Pacific Northwest.

    Science.gov (United States)

    R. Bruce Bury; Paul Stephen. Corn

    1991-01-01

    Methods describing how to sample aquatic and semiaquatic amphibians in small streams and headwater habitats in the Pacific Northwest are presented. We developed a technique that samples 10-meter stretches of selected streams, which was adequate to detect presence or absence of amphibian species and provided sample sizes statistically sufficient to compare abundance of...

  8. A random spatial sampling method in a rural developing nation

    Science.gov (United States)

    Michelle C. Kondo; Kent D.W. Bream; Frances K. Barg; Charles C. Branas

    2014-01-01

    Nonrandom sampling of populations in developing nations has limitations and can inaccurately estimate health phenomena, especially among hard-to-reach populations such as rural residents. However, random sampling of rural populations in developing nations can be challenged by incomplete enumeration of the base population. We describe a stratified random sampling method...

  9. Multielement methods of atomic fluorescence analysis of enviromental samples

    International Nuclear Information System (INIS)

    Rigin, V.I.

    1985-01-01

    A multielement method of atomic fluorescence analysis of environmental samples based on sample decomposition by autoclave fluorination and gas-phase atomization of volatile compounds in inductive araon plasma using a nondispersive polychromator is suggested. Detection limits of some elements (Be, Sr, Cd, V, Mo, Te, Ru etc.) for different sample forms introduced in to an analyzer are given

  10. Sampling bee communities using pan traps: alternative methods increase sample size

    Science.gov (United States)

    Monitoring of the status of bee populations and inventories of bee faunas require systematic sampling. Efficiency and ease of implementation has encouraged the use of pan traps to sample bees. Efforts to find an optimal standardized sampling method for pan traps have focused on pan trap color. Th...

  11. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses.

    Science.gov (United States)

    De Lange, H J; Van Griethuysen, C; Koelmans, A A

    2008-01-01

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics.

  12. Uniform Sampling Table Method and its Applications II--Evaluating the Uniform Sampling by Experiment.

    Science.gov (United States)

    Chen, Yibin; Chen, Jiaxi; Chen, Xuan; Wang, Min; Wang, Wei

    2015-01-01

    A new method of uniform sampling is evaluated in this paper. The items and indexes were adopted to evaluate the rationality of the uniform sampling. The evaluation items included convenience of operation, uniformity of sampling site distribution, and accuracy and precision of measured results. The evaluation indexes included operational complexity, occupation rate of sampling site in a row and column, relative accuracy of pill weight, and relative deviation of pill weight. They were obtained from three kinds of drugs with different shape and size by four kinds of sampling methods. Gray correlation analysis was adopted to make the comprehensive evaluation by comparing it with the standard method. The experimental results showed that the convenience of uniform sampling method was 1 (100%), odds ratio of occupation rate in a row and column was infinity, relative accuracy was 99.50-99.89%, reproducibility RSD was 0.45-0.89%, and weighted incidence degree exceeded the standard method. Hence, the uniform sampling method was easy to operate, and the selected samples were distributed uniformly. The experimental results demonstrated that the uniform sampling method has good accuracy and reproducibility, which can be put into use in drugs analysis.

  13. THE USE OF RANKING SAMPLING METHOD WITHIN MARKETING RESEARCH

    Directory of Open Access Journals (Sweden)

    CODRUŢA DURA

    2011-01-01

    Full Text Available Marketing and statistical literature available to practitioners provides a wide range of sampling methods that can be implemented in the context of marketing research. Ranking sampling method is based on taking apart the general population into several strata, namely into several subdivisions which are relatively homogenous regarding a certain characteristic. In fact, the sample will be composed by selecting, from each stratum, a certain number of components (which can be proportional or non-proportional to the size of the stratum until the pre-established volume of the sample is reached. Using ranking sampling within marketing research requires the determination of some relevant statistical indicators - average, dispersion, sampling error etc. To that end, the paper contains a case study which illustrates the actual approach used in order to apply the ranking sample method within a marketing research made by a company which provides Internet connection services, on a particular category of customers – small and medium enterprises.

  14. An efficient method for sampling the essential subspace of proteins

    NARCIS (Netherlands)

    Amadei, A; Linssen, A.B M; de Groot, B.L.; van Aalten, D.M.F.; Berendsen, H.J.C.

    A method is presented for a more efficient sampling of the configurational space of proteins as compared to conventional sampling techniques such as molecular dynamics. The method is based on the large conformational changes in proteins revealed by the ''essential dynamics'' analysis. A form of

  15. Neonatal blood gas sampling methods | Goenka | South African ...

    African Journals Online (AJOL)

    There is little published guidance that systematically evaluates the different methods of neonatal blood gas sampling, where each method has its individual benefits and risks. This review critically surveys the available evidence to generate a comparison between arterial and capillary blood gas sampling, focusing on their ...

  16. A Rapid Assessment of Macroinvertebrates Associated with Salvinia ...

    African Journals Online (AJOL)

    Salvinia molesta is an invasive species in the Okavango Delta. The plant forms monotypic covers in places where it occurs and thus affects macroinvertebrates diversity within them. Three habitats with low, moderate and heavy infestation by the weed were selected inside Moremi Game Reserve to study macroinvertebrates ...

  17. Effect of sewage oxidation pond effluent on macroinvertebrate ...

    African Journals Online (AJOL)

    The influence on aquatic macroinvertebrates of sewage oxidation pond effluent discharge was investigated in a tropical forest stream in Ile-Ife, Nigeria. A total of 858 individual macroinvertebrates were collected. They belong to 8 taxa which represent 5 orders. The number of taxa was low when compared to the findings in ...

  18. Turnover patterns in fish versus macroinvertebrates — implications ...

    African Journals Online (AJOL)

    Spatial patterns in taxonomic richness and turnover for fish and aquatic macroinvertebrates are compared to assess the relative usefulness of each taxonomic group in mapping biodiversity patterns. Fish and aquatic macroinvertebrate species data for sites down the longitudinal axes of nine rivers in four provinces along the ...

  19. La Popala creek: quality analysis of water from some physical - chemical, microbiological variables and aquatic macroinvertebrates

    International Nuclear Information System (INIS)

    Milan Valoyes, Wandy Yohanna; Caicedo Quintero, Orlando; Aguirre Ramirez, Nestor Jaime

    2011-01-01

    The Popala creek supplies water to the people of Bolombolo in Venecia municipality in Antioquia, Colombia. In November 14th and 28th of 2009, four sampling station were located along the creek, to measure five sets of variables: physico- chemical, microbiological, aquatic macroinvertebrate, biological indicators and biotic index BMWP.Physico- chemical variables, aquatic macroinvertebrates and index BMWP indicate good environmental conditions in station 2, located about 150 m from the headwaters (station 1). On the other hand, Station 4, located near to the Cauca River, exhibits deterioration in water quality. Stations 3 and 4 displayed high levels of fecal coliforms. However, the samples taken from Bolombolo's water supply network indicate the water of the aqueduct is adequate for human consumption.

  20. A Mixed Methods Sampling Methodology for a Multisite Case Study

    Science.gov (United States)

    Sharp, Julia L.; Mobley, Catherine; Hammond, Cathy; Withington, Cairen; Drew, Sam; Stringfield, Sam; Stipanovic, Natalie

    2012-01-01

    The flexibility of mixed methods research strategies makes such approaches especially suitable for multisite case studies. Yet the utilization of mixed methods to select sites for these studies is rarely reported. The authors describe their pragmatic mixed methods approach to select a sample for their multisite mixed methods case study of a…

  1. Present status of NMCC and sample preparation method for bio-samples

    International Nuclear Information System (INIS)

    Futatsugawa, S.; Hatakeyama, S.; Saitou, S.; Sera, K.

    1993-01-01

    In NMCC(Nishina Memorial Cyclotron Center) we are doing researches on PET of nuclear medicine (Positron Emission Computed Tomography) and PIXE analysis (Particle Induced X-ray Emission) using a small cyclotron of compactly designed. The NMCC facilities have been opened to researchers of other institutions since April 1993. The present status of NMCC is described. Bio-samples (medical samples, plants, animals and environmental samples) have mainly been analyzed by PIXE in NMCC. Small amounts of bio-samples for PIXE are decomposed quickly and easily in a sealed PTFE (polytetrafluoroethylene) vessel with a microwave oven. This sample preparation method of bio-samples also is described. (author)

  2. Soil macroinvertebrate communities across a productivity gradient in deciduous forests of eastern North America

    Science.gov (United States)

    Evelyn S. Wenk; Mac A. Callaham; Joseph O' Brien; Paul J. Hanson

    2016-01-01

    Within the temperate, deciduous forests of the eastern US, diverse soil-fauna communities are structured by a combination of environmental gradients and interactions with other biota. The introduction of non-native soil taxa has altered communities and soil processes, and adds another degree of variability to these systems. We sampled soil macroinvertebrate abundance...

  3. Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

    Directory of Open Access Journals (Sweden)

    Tony J Popic

    Full Text Available Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2 area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

  4. Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

    Science.gov (United States)

    Popic, Tony J; Davila, Yvonne C; Wardle, Glenda M

    2013-01-01

    Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2) area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

  5. Colonization of leaf litter of two aquatic macrophytes, Mayaca fluviatilis Aublet and Salvinia auriculata Aublet by aquatic macroinvertebrates in a tropical reservoir

    Directory of Open Access Journals (Sweden)

    Marcia Cristina de Paula

    2011-04-01

    Full Text Available Decomposition and colonization of S. auriculata and M. fluviatilis by macroinvertebrates were analyzed during 40 days to determine whether differences existed on colonization by aquatic macroinvertebrates of two macrophytes with distinct habits (submerged versus fluctuant. Leaf litter of S. auriculata and M. fluviatilis were incubated in 24 litter bags (12 of each species, in a small reservoir surrounded by a cerrado fragment with low level of anthropic impact. After 10, 20, 30 and 40 days, the litter bags were removed and aquatic macroinvertebrates community was analyzed. Two hundred twenty macroinvertebrates were associated with S. auriculata and 261 were associated with M. fluviatilis, identified in 24 taxa. Both macrophyte species were colonized mainly by macroinvertebrate predators. Ablabesmyia with predator and collector food mechanisms was present in all sampling. The data showed an expressive increase of abundance during the process of decomposition and a decrease at the end of the experiment, in both macrophytes. Cluster analysis permitted inference that the colonization of the leaf liter by macroinvertebrates was determinated by incubation time of leaf litter not by the habit of macrophytes (submerged or fluctuant.

  6. Multi-frequency direct sampling method in inverse scattering problem

    Science.gov (United States)

    Kang, Sangwoo; Lambert, Marc; Park, Won-Kwang

    2017-10-01

    We consider the direct sampling method (DSM) for the two-dimensional inverse scattering problem. Although DSM is fast, stable, and effective, some phenomena remain unexplained by the existing results. We show that the imaging function of the direct sampling method can be expressed by a Bessel function of order zero. We also clarify the previously unexplained imaging phenomena and suggest multi-frequency DSM to overcome traditional DSM. Our method is evaluated in simulation studies using both single and multiple frequencies.

  7. Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

    Science.gov (United States)

    M.A. Callaham; J.M. Blair; T.C. Todd; D.J. Kitchen; M.R. Whiles

    2003-01-01

    The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups. and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station. we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term...

  8. DOE methods for evaluating environmental and waste management samples

    International Nuclear Information System (INIS)

    Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

    1994-04-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Laboratory Management Division of the DOE. Methods are prepared for entry into DOE Methods as chapter editors, together with DOE and other participants in this program, identify analytical and sampling method needs. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types. open-quotes Draftclose quotes or open-quotes Verified.close quotes. open-quotes Draftclose quotes methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. open-quotes Verifiedclose quotes methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations

  9. Interval sampling methods and measurement error: a computer simulation.

    Science.gov (United States)

    Wirth, Oliver; Slaven, James; Taylor, Matthew A

    2014-01-01

    A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method's inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments. © Society for the Experimental Analysis of Behavior.

  10. Changes of Benthic Macroinvertebrates in Thi Vai River and Cai Mep Estuaries Under Polluted Conditions with Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Huong Nguyen Thi Thanh

    2017-06-01

    Full Text Available The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries. In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO, total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment. The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 - 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 - 5.70 mg/L 0.024 - 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 - 2.746 individuals/m−1 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results

  11. Effects of local land-use on riparian vegetation, water quality, and the functional organization of macroinvertebrate assemblages.

    Science.gov (United States)

    Fierro, Pablo; Bertrán, Carlos; Tapia, Jaime; Hauenstein, Enrique; Peña-Cortés, Fernando; Vergara, Carolina; Cerna, Cindy; Vargas-Chacoff, Luis

    2017-12-31

    Land-use change is a principal factor affecting riparian vegetation and river biodiversity. In Chile, land-use change has drastically intensified over the last decade, with native forests converted to exotic forest plantations and agricultural land. However, the effects thereof on aquatic ecosystems are not well understood. Closing this knowledge gap first requires understanding how human perturbations affect riparian and stream biota. Identified biological indicators could then be applied to determine the health of fluvial ecosystems. Therefore, this study investigated the effects of land-use change on the health of riparian and aquatic ecosystems by assessing riparian vegetation, water quality, benthic macroinvertebrate assemblages, and functional feeding groups. Twenty-one sites in catchment areas with different land-uses (i.e. pristine forests, native forests, exotic forest plantations, and agricultural land) were selected and sampled during the 2010 to 2012 dry seasons. Riparian vegetation quality was highest in pristine forests. Per the modified Macroinvertebrate Family Biotic Index for Chilean species, the best conditions existed in native forests and the worst in agricultural catchments. Water quality and macroinvertebrate assemblages significantly varied across land-use areas, with forest plantations and agricultural land having high nutrient concentrations, conductivity, suspended solids, and apparent color. Macroinvertebrate assemblage diversity was lowest for agricultural and exotic forest plantation catchments, with notable non-insect representation. Collector-gatherers were the most abundant functional feeding group, suggesting importance independent of land-use. Land-use areas showed no significant differences in functional feeding groups. In conclusion, anthropogenic land-use changes were detectable through riparian quality, water quality, and macroinvertebrate assemblages, but not through functional feeding groups. These data, particularly the

  12. Direct sampling methods for inverse elastic scattering problems

    Science.gov (United States)

    Ji, Xia; Liu, Xiaodong; Xi, Yingxia

    2018-03-01

    We consider the inverse elastic scattering of incident plane compressional and shear waves from the knowledge of the far field patterns. Specifically, three direct sampling methods for location and shape reconstruction are proposed using the different component of the far field patterns. Only inner products are involved in the computation, thus the novel sampling methods are very simple and fast to be implemented. With the help of the factorization of the far field operator, we give a lower bound of the proposed indicator functionals for sampling points inside the scatterers. While for the sampling points outside the scatterers, we show that the indicator functionals decay like the Bessel functions as the sampling point goes away from the boundary of the scatterers. We also show that the proposed indicator functionals continuously dependent on the far field patterns, which further implies that the novel sampling methods are extremely stable with respect to data error. For the case when the observation directions are restricted into the limited aperture, we firstly introduce some data retrieval techniques to obtain those data that can not be measured directly and then use the proposed direct sampling methods for location and shape reconstructions. Finally, some numerical simulations in two dimensions are conducted with noisy data, and the results further verify the effectiveness and robustness of the proposed sampling methods, even for multiple multiscale cases and limited-aperture problems.

  13. Sampling and analysis methods for geothermal fluids and gases

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.C.

    1978-07-01

    The sampling procedures for geothermal fluids and gases include: sampling hot springs, fumaroles, etc.; sampling condensed brine and entrained gases; sampling steam-lines; low pressure separator systems; high pressure separator systems; two-phase sampling; downhole samplers; and miscellaneous methods. The recommended analytical methods compiled here cover physical properties, dissolved solids, and dissolved and entrained gases. The sequences of methods listed for each parameter are: wet chemical, gravimetric, colorimetric, electrode, atomic absorption, flame emission, x-ray fluorescence, inductively coupled plasma-atomic emission spectroscopy, ion exchange chromatography, spark source mass spectrometry, neutron activation analysis, and emission spectrometry. Material on correction of brine component concentrations for steam loss during flashing is presented. (MHR)

  14. Field Sample Preparation Method Development for Isotope Ratio Mass Spectrometry

    International Nuclear Information System (INIS)

    Leibman, C.; Weisbrod, K.; Yoshida, T.

    2015-01-01

    Non-proliferation and International Security (NA-241) established a working group of researchers from Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) to evaluate the utilization of in-field mass spectrometry for safeguards applications. The survey of commercial off-the-shelf (COTS) mass spectrometers (MS) revealed no instrumentation existed capable of meeting all the potential safeguards requirements for performance, portability, and ease of use. Additionally, fieldable instruments are unlikely to meet the International Target Values (ITVs) for accuracy and precision for isotope ratio measurements achieved with laboratory methods. The major gaps identified for in-field actinide isotope ratio analysis were in the areas of: 1. sample preparation and/or sample introduction, 2. size reduction of mass analyzers and ionization sources, 3. system automation, and 4. decreased system cost. Development work in 2 through 4, numerated above continues, in the private and public sector. LANL is focusing on developing sample preparation/sample introduction methods for use with the different sample types anticipated for safeguard applications. Addressing sample handling and sample preparation methods for MS analysis will enable use of new MS instrumentation as it becomes commercially available. As one example, we have developed a rapid, sample preparation method for dissolution of uranium and plutonium oxides using ammonium bifluoride (ABF). ABF is a significantly safer and faster alternative to digestion with boiling combinations of highly concentrated mineral acids. Actinides digested with ABF yield fluorides, which can then be analyzed directly or chemically converted and separated using established column chromatography techniques as needed prior to isotope analysis. The reagent volumes and the sample processing steps associated with ABF sample digestion lend themselves to automation and field

  15. Agricultural Rivers at Risk: Dredging Results in a Loss of Macroinvertebrates. Preliminary Observations from the Narew Catchment, Poland

    Directory of Open Access Journals (Sweden)

    Mateusz Grygoruk

    2015-08-01

    Full Text Available Ecosystem deterioration in small lowland agricultural rivers that results from river dredging entails a significant threat to the appropriate ecohydrological conditions of these water bodies, expressed as homogenization of habitats and loss of biodiversity. Our study was aimed at a comparison of abundance and taxonomic structure of bottom-dwelling macroinvertebrates in dredged and non-dredged stretches of small lowland rivers and tributaries of the middle Narew River, namely: Czaplinianka, Turośnianka, Dąb, and Ślina. The experimental setup was (1 to collect samples of the bottom material from the river stretches that either persisted in a non-modified state (dredging was not done there in the last few years or had been subjected to river dredging in the year of sampling; and (2 to analyze the abundance and taxonomic structure of macroinvertebrates in the collected samples. The study revealed that at the high level of statistical significance (from p = 0.025 to p = 0.001, the total abundance of riverbed macroinvertebrates in the dredged stretches of the rivers analyzed was approximately 70% lower than in non-dredged areas. We state that the dredging of small rivers in agricultural landscapes seriously affects their ecological status by negatively influencing the concentrations and species richness of benthic macroinvertebrates.

  16. Richness of littoral macroinvertebrate communities in mountain ponds from NW Spain: what factors does it depend on?

    Directory of Open Access Journals (Sweden)

    Francisco Garcia-Criado

    2012-01-01

    Full Text Available Recent researches have started to provide useful information on the littoral macroinvertebrates living in European mountain ponds. However, there is still uncertainty on the factors really shaping their communities. Understanding patterns of biodiversity in these systems is essential for conservation and management purposes. In this paper, we sampled littoral macroinvertebrates at 51 mountain ponds from a wide Spanish region (Castilla y León in order to define which of a set of environmental variables were responsible for differences in richness (genus level or above. One macroinvertebrate sample was collected at each pond (in late June or early July between 2004 and 2008 by kicking and sweeping following a multihabitat time-limited sampling. Twenty-four variables measured at 39 ponds were used to generate a predictive model by multiple linear regression. This model revealed number of habitats and fish stocking as the only significant variables, showing their relative importance against variables traditionally considered to influence richness in mountain ponds and lakes (for example, altitude and pond size. Furthermore, this model accurately predicted richness when tested on a new set of twelve ponds. Additional data analyses proved that neither altitude nor habitat type significantly influenced macroinvertebrate richness, while water permanence had a slight effect (the number of taxa was slightly lower in temporary than in permanent ponds.

  17. A direct sampling method to an inverse medium scattering problem

    KAUST Repository

    Ito, Kazufumi; Jin, Bangti; Zou, Jun

    2012-01-01

    In this work we present a novel sampling method for time harmonic inverse medium scattering problems. It provides a simple tool to directly estimate the shape of the unknown scatterers (inhomogeneous media), and it is applicable even when

  18. A direct sampling method for inverse electromagnetic medium scattering

    KAUST Repository

    Ito, Kazufumi; Jin, Bangti; Zou, Jun

    2013-01-01

    In this paper, we study the inverse electromagnetic medium scattering problem of estimating the support and shape of medium scatterers from scattered electric/magnetic near-field data. We shall develop a novel direct sampling method based

  19. Evaluation of the point-centred-quarter method of sampling ...

    African Journals Online (AJOL)

    -quarter method.The parameter which was most efficiently sampled was species composition relativedensity) with 90% replicate similarity being achieved with 100 point-centred-quarters. However, this technique cannot be recommended, even ...

  20. Field evaluation of personal sampling methods for multiple bioaerosols.

    Science.gov (United States)

    Wang, Chi-Hsun; Chen, Bean T; Han, Bor-Cheng; Liu, Andrew Chi-Yeu; Hung, Po-Chen; Chen, Chih-Yong; Chao, Hsing Jasmine

    2015-01-01

    Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

  1. Adaptive cluster sampling: An efficient method for assessing inconspicuous species

    Science.gov (United States)

    Andrea M. Silletti; Joan Walker

    2003-01-01

    Restorationistis typically evaluate the success of a project by estimating the population sizes of species that have been planted or seeded. Because total census is raely feasible, they must rely on sampling methods for population estimates. However, traditional random sampling designs may be inefficient for species that, for one reason or another, are challenging to...

  2. Field evaluation of personal sampling methods for multiple bioaerosols.

    Directory of Open Access Journals (Sweden)

    Chi-Hsun Wang

    Full Text Available Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min. Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

  3. Global metabolite analysis of yeast: evaluation of sample preparation methods

    DEFF Research Database (Denmark)

    Villas-Bôas, Silas Granato; Højer-Pedersen, Jesper; Åkesson, Mats Fredrik

    2005-01-01

    Sample preparation is considered one of the limiting steps in microbial metabolome analysis. Eukaryotes and prokaryotes behave very differently during the several steps of classical sample preparation methods for analysis of metabolites. Even within the eukaryote kingdom there is a vast diversity...

  4. A distance limited method for sampling downed coarse woody debris

    Science.gov (United States)

    Jeffrey H. Gove; Mark J. Ducey; Harry T. Valentine; Michael S. Williams

    2012-01-01

    A new sampling method for down coarse woody debris is proposed based on limiting the perpendicular distance from individual pieces to a randomly chosen sample point. Two approaches are presented that allow different protocols to be used to determine field measurements; estimators for each protocol are also developed. Both protocols are compared via simulation against...

  5. A comprehensive comparison of perpendicular distance sampling methods for sampling downed coarse woody debris

    Science.gov (United States)

    Jeffrey H. Gove; Mark J. Ducey; Harry T. Valentine; Michael S. Williams

    2013-01-01

    Many new methods for sampling down coarse woody debris have been proposed in the last dozen or so years. One of the most promising in terms of field application, perpendicular distance sampling (PDS), has several variants that have been progressively introduced in the literature. In this study, we provide an overview of the different PDS variants and comprehensive...

  6. Approximation of the exponential integral (well function) using sampling methods

    Science.gov (United States)

    Baalousha, Husam Musa

    2015-04-01

    Exponential integral (also known as well function) is often used in hydrogeology to solve Theis and Hantush equations. Many methods have been developed to approximate the exponential integral. Most of these methods are based on numerical approximations and are valid for a certain range of the argument value. This paper presents a new approach to approximate the exponential integral. The new approach is based on sampling methods. Three different sampling methods; Latin Hypercube Sampling (LHS), Orthogonal Array (OA), and Orthogonal Array-based Latin Hypercube (OA-LH) have been used to approximate the function. Different argument values, covering a wide range, have been used. The results of sampling methods were compared with results obtained by Mathematica software, which was used as a benchmark. All three sampling methods converge to the result obtained by Mathematica, at different rates. It was found that the orthogonal array (OA) method has the fastest convergence rate compared with LHS and OA-LH. The root mean square error RMSE of OA was in the order of 1E-08. This method can be used with any argument value, and can be used to solve other integrals in hydrogeology such as the leaky aquifer integral.

  7. Spatial and temporal distribution of benthic macroinvertebrates in a Southeastern Brazilian river.

    Science.gov (United States)

    Silveira, M P; Buss, D F; Nessimian, J L; Baptista, D F

    2006-05-01

    Benthic macroinvertebrate assemblages are structured according to physical and chemical parameters that define microhabitats, including food supply, shelter to escape predators, and other biological parameters that influence reproductive success. The aim of this study is to investigate spatial and temporal distribution of macroinvertebrate assemblages at the Macaé river basin, in Rio de Janeiro state, Southeastern Brazil. According to the "Habitat Assessment Field Data Sheet--High Gradient Streams" (Barbour et al., 1999), the five sampling sites are considered as a reference condition. Despite the differences in hydrological parameters (mean width, depth and discharge) among sites, the physicochemical parameters and functional feeding groups' general structure were similar, except for the less impacted area, which showed more shredders. According to the Detrended Correspondence Analysis based on substrates, there is a clear distinction between pool and riffle assemblages. In fact, the riffle litter substrate had higher taxa in terms of richness and abundance, but the pool litter substrate had the greatest number of exclusive taxa. A Cluster Analysis based on sampling sites data showed that temporal variation was the main factor in structuring macroinvertebrate assemblages in the studied habitats.

  8. Neutron activation analysis of certified samples by the absolute method

    Science.gov (United States)

    Kadem, F.; Belouadah, N.; Idiri, Z.

    2015-07-01

    The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

  9. DOE methods for evaluating environmental and waste management samples

    International Nuclear Information System (INIS)

    Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

    1994-10-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Analytical Services Division of DOE. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types, open-quotes Draftclose quotes or open-quotes Verifiedclose quotes. open-quotes Draftclose quotes methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. open-quotes Verifiedclose quotes methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations. These methods have delineated measures of precision and accuracy

  10. DOE methods for evaluating environmental and waste management samples

    Energy Technology Data Exchange (ETDEWEB)

    Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K. [eds.

    1994-10-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Analytical Services Division of DOE. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types, {open_quotes}Draft{close_quotes} or {open_quotes}Verified{close_quotes}. {open_quotes}Draft{close_quotes} methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. {open_quotes}Verified{close_quotes} methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations. These methods have delineated measures of precision and accuracy.

  11. Effects of watershed and in-stream liming on macroinvertebrate communities in acidified tributaries to an Adirondack lake

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.; Lawrence, Gregory B.; Fuller, Randall L.

    2018-01-01

    Liming techniques are being explored as a means to accelerate the recovery of aquatic biota from decades of acid deposition in many regions. The preservation or restoration of native sportfish populations has typically been the impetus for liming programs, and as such, less attention has been given to its effects on other biological assemblages such as macroinvertebrates. Furthermore, the differing effects of various lime application strategies such as in-stream and watershed applications are not well understood. In 2012, a program was initiated using in-stream and aerial (whole-watershed) liming to improve water quality and Brook Trout (Salvelinus fontinalis) recruitment in three acidified tributaries of a high-elevation Adirondack lake in New York State. Concurrently, macroinvertebrates were sampled annually between 2013 and 2016 at 3 treated sites and 3 untreated reference sites to assess the effects of each liming technique on this community. Despite improvements in water chemistry in all three limed streams, our results generally suggest that neither liming technique succeeded in improving the condition of macroinvertebrate communities. The watershed application caused an immediate and unsustained decrease in the density of macroinvertebrates and increase in the proportion of sensitive taxa. These changes were driven primarily by a one-year 71 percent reduction of the acid-tolerant Leuctra stoneflies and likely represent an initial chemistry shock from the lime application rather than a recovery response. The in-stream applications appeared to reduce the density of macroinvertebrates, particularly in one stream where undissolved lime covered the natural substrate. The close proximity of our study sites to the in-stream application points (50 and 1230 m) may partly explain these negative effects. Our results are consistent with prior studies of in-stream liming which indicate that this technique often fails to restore macroinvertebrate communities to a pre

  12. On-capillary sample cleanup method for the electrophoretic determination of carbohydrates in juice samples.

    Science.gov (United States)

    Morales-Cid, Gabriel; Simonet, Bartolomé M; Cárdenas, Soledad; Valcárcel, Miguel

    2007-05-01

    On many occasions, sample treatment is a critical step in electrophoretic analysis. As an alternative to batch procedures, in this work, a new strategy is presented with a view to develop an on-capillary sample cleanup method. This strategy is based on the partial filling of the capillary with carboxylated single-walled carbon nanotube (c-SWNT). The nanoparticles retain interferences from the matrix allowing the determination and quantification of carbohydrates (viz glucose, maltose and fructose). The precision of the method for the analysis of real samples ranged from 5.3 to 6.4%. The proposed method was compared with a method based on a batch filtration of the juice sample through diatomaceous earth and further electrophoretic determination. This method was also validated in this work. The RSD for this other method ranged from 5.1 to 6%. The results obtained by both methods were statistically comparable demonstrating the accuracy of the proposed methods and their effectiveness. Electrophoretic separation of carbohydrates was achieved using 200 mM borate solution as a buffer at pH 9.5 and applying 15 kV. During separation, the capillary temperature was kept constant at 40 degrees C. For the on-capillary cleanup method, a solution containing 50 mg/L of c-SWNTs prepared in 300 mM borate solution at pH 9.5 was introduced for 60 s into the capillary just before sample introduction. For the electrophoretic analysis of samples cleaned in batch with diatomaceous earth, it is also recommended to introduce into the capillary, just before the sample, a 300 mM borate solution as it enhances the sensitivity and electrophoretic resolution.

  13. Validation of method in instrumental NAA for food products sample

    International Nuclear Information System (INIS)

    Alfian; Siti Suprapti; Setyo Purwanto

    2010-01-01

    NAA is a method of testing that has not been standardized. To affirm and confirm that this method is valid. it must be done validation of the method with various sample standard reference materials. In this work. the validation is carried for food product samples using NIST SRM 1567a (wheat flour) and NIST SRM 1568a (rice flour). The results show that the validation method for testing nine elements (Al, K, Mg, Mn, Na, Ca, Fe, Se and Zn) in SRM 1567a and eight elements (Al, K, Mg, Mn, Na, Ca, Se and Zn ) in SRM 1568a pass the test of accuracy and precision. It can be conclude that this method has power to give valid result in determination element of the food products samples. (author)

  14. Benthic macroinvertebrates as ecological indicators for estuarine and coastal ecosystems : assessment and intercalibration

    OpenAIRE

    Teixeira, Heliana Lilita Gonçalves

    2010-01-01

    Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra The aim of the research work presented in this thesis is to be a contribution to the field of ecological assessment in coastal and transitional ecosystems. The main goals were: a) to present a method for the assessment of the ecological status of benthic macroinvertebrate communities in Portuguese transitional waters that would meet the requirements of the Eur...

  15. Extending the alias Monte Carlo sampling method to general distributions

    International Nuclear Information System (INIS)

    Edwards, A.L.; Rathkopf, J.A.; Smidt, R.K.

    1991-01-01

    The alias method is a Monte Carlo sampling technique that offers significant advantages over more traditional methods. It equals the accuracy of table lookup and the speed of equal probable bins. The original formulation of this method sampled from discrete distributions and was easily extended to histogram distributions. We have extended the method further to applications more germane to Monte Carlo particle transport codes: continuous distributions. This paper presents the alias method as originally derived and our extensions to simple continuous distributions represented by piecewise linear functions. We also present a method to interpolate accurately between distributions tabulated at points other than the point of interest. We present timing studies that demonstrate the method's increased efficiency over table lookup and show further speedup achieved through vectorization. 6 refs., 12 figs., 2 tabs

  16. Soil separator and sampler and method of sampling

    Science.gov (United States)

    O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

    2010-02-16

    A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

  17. Methods of human body odor sampling: the effect of freezing.

    Science.gov (United States)

    Lenochova, Pavlina; Roberts, S Craig; Havlicek, Jan

    2009-02-01

    Body odor sampling is an essential tool in human chemical ecology research. However, methodologies of individual studies vary widely in terms of sampling material, length of sampling, and sample processing. Although these differences might have a critical impact on results obtained, almost no studies test validity of current methods. Here, we focused on the effect of freezing samples between collection and use in experiments involving body odor perception. In 2 experiments, we tested whether axillary odors were perceived differently by raters when presented fresh or having been frozen and whether several freeze-thaw cycles affected sample quality. In the first experiment, samples were frozen for 2 weeks, 1 month, or 4 months. We found no differences in ratings of pleasantness, attractiveness, or masculinity between fresh and frozen samples. Similarly, almost no differences between repeatedly thawed and fresh samples were found. We found some variations in intensity; however, this was unrelated to length of storage. The second experiment tested differences between fresh samples and those frozen for 6 months. Again no differences in subjective ratings were observed. These results suggest that freezing has no significant effect on perceived odor hedonicity and that samples can be reliably used after storage for relatively long periods.

  18. Probability Sampling Method for a Hidden Population Using Respondent-Driven Sampling: Simulation for Cancer Survivors.

    Science.gov (United States)

    Jung, Minsoo

    2015-01-01

    When there is no sampling frame within a certain group or the group is concerned that making its population public would bring social stigma, we say the population is hidden. It is difficult to approach this kind of population survey-methodologically because the response rate is low and its members are not quite honest with their responses when probability sampling is used. The only alternative known to address the problems caused by previous methods such as snowball sampling is respondent-driven sampling (RDS), which was developed by Heckathorn and his colleagues. RDS is based on a Markov chain, and uses the social network information of the respondent. This characteristic allows for probability sampling when we survey a hidden population. We verified through computer simulation whether RDS can be used on a hidden population of cancer survivors. According to the simulation results of this thesis, the chain-referral sampling of RDS tends to minimize as the sample gets bigger, and it becomes stabilized as the wave progresses. Therefore, it shows that the final sample information can be completely independent from the initial seeds if a certain level of sample size is secured even if the initial seeds were selected through convenient sampling. Thus, RDS can be considered as an alternative which can improve upon both key informant sampling and ethnographic surveys, and it needs to be utilized for various cases domestically as well.

  19. Biodiversity assessment of benthic macroinvertebrates along a reservoir cascade in the lower São Francisco river (northeastern Brazil

    Directory of Open Access Journals (Sweden)

    M. Callisto

    Full Text Available In order to verify the cascade-system effect in benthic macroinvertebrate communities, and the implications for policy making and proposals for conservation and sustainable use of the lower portion of São Francisco river basin (Bahia State, Brazil, a three-reservoir cascade system including two stretches downstream were studied during dry (June, 1997 and rainy (March, 1998 periods. The dominant groups found were Mollusca (Melanoides tuberculata, Oligochaeta, and Chironomidae larvae. Low Shannon-Wiener and Pielou index values were found, but with no significant difference between the sampling periods. However, density and taxonomic richness were significantly different (t(0.05; 31 = -2.1945; p < 0.05; e t(0.05; 31 = -3.0600; p < 0.01 between the sampling periods, with a reduction in the number of taxaand macroinvertebrate abundance during the rainy period. An increasing gradient in benthic macroinvertebrate community structures was noted along the reservoir cascade from the first reservoir (Apolônio Sales, followed by a decrease downstream from the third reservoir of the system (Xingó. Despite the negative consequences of rapid proliferation of dams, which have caused widespread loss of freshwater habitats, the reservoir cascade system promoted an increase in benthic macroinvertebrate diversity, due to water-quality improvement along the system.

  20. Predicted macroinvertebrate response to water diversion from a montane stream using two-dimensional hydrodynamic models and zero flow approximation

    Science.gov (United States)

    Holmquist, Jeffrey G.; Waddle, Terry J.

    2013-01-01

    We used two-dimensional hydrodynamic models for the assessment of water diversion effects on benthic macroinvertebrates and associated habitat in a montane stream in Yosemite National Park, Sierra Nevada Mountains, CA, USA. We sampled the macroinvertebrate assemblage via Surber sampling, recorded detailed measurements of bed topography and flow, and coupled a two-dimensional hydrodynamic model with macroinvertebrate indicators to assess habitat across a range of low flows in 2010 and representative past years. We also made zero flow approximations to assess response of fauna to extreme conditions. The fauna of this montane reach had a higher percentage of Ephemeroptera, Plecoptera, and Trichoptera (%EPT) than might be expected given the relatively low faunal diversity of the study reach. The modeled responses of wetted area and area-weighted macroinvertebrate metrics to decreasing discharge indicated precipitous declines in metrics as flows approached zero. Changes in area-weighted metrics closely approximated patterns observed for wetted area, i.e., area-weighted invertebrate metrics contributed relatively little additional information above that yielded by wetted area alone. Loss of habitat area in this montane stream appears to be a greater threat than reductions in velocity and depth or changes in substrate, and the modeled patterns observed across years support this conclusion. Our models suggest that step function losses of wetted area may begin when discharge in the Merced falls to 0.02 m3/s; proportionally reducing diversions when this threshold is reached will likely reduce impacts in low flow years.

  1. Investigating the influence of heavy metals on macro-invertebrate assemblages using Partial Cononical Correspondence Analysis (pCCA)

    Science.gov (United States)

    Beasley, Gary; Kneale, Pauline E.

    This paper defines the spectrum of impairment to stream macroinvertebrates arising from urban runoff. Field sampling of stream sediments at 62 sites across Yorkshire, UK was used to investigate the influence of heavy metals and habitat on macroinvertebrate family distribution using partial Canonical Correspondence Analysis (pCCA). Increasing urbanization and trafficking was associated with increasing levels of metal pollution but, even when traffic is light, family numbers can be reduced by 50%. Industrial areas and motorway runoff depress macroinvertebrate numbers but drainage from streets with no off-road parking in residential areas can have similar impacts. The heavy metals in the sediment accounted for approximately 24% of the variation in macroinvertebrate community composition while the physical habitat variables used in RIVPACS (River InVertebrate Prediction And Classification System) (Wright, 2000) accounted for an additional 30%. Zinc and nickel were the main metal influences regardless of the time of sampling; at these sites copper is less than critical. Results agree with those reported in other studies in which families mainly from the orders Ephemeroptera (mayfly), Plecoptera (stonefly) and Tricoptera (caddisfly) displayed metal sensitivity in that they were absent from metal polluted streams. However, within each of these orders, a continuum of sensitivity is evident: this highlights the risks of generalising on orders rather than using family or indeed species data.

  2. Efficiency of snake sampling methods in the Brazilian semiarid region.

    Science.gov (United States)

    Mesquita, Paula C M D; Passos, Daniel C; Cechin, Sonia Z

    2013-09-01

    The choice of sampling methods is a crucial step in every field survey in herpetology. In countries where time and financial support are limited, the choice of the methods is critical. The methods used to sample snakes often lack objective criteria, and the traditional methods have apparently been more important when making the choice. Consequently researches using not-standardized methods are frequently found in the literature. We have compared four commonly used methods for sampling snake assemblages in a semiarid area in Brazil. We compared the efficacy of each method based on the cost-benefit regarding the number of individuals and species captured, time, and financial investment. We found that pitfall traps were the less effective method in all aspects that were evaluated and it was not complementary to the other methods in terms of abundance of species and assemblage structure. We conclude that methods can only be considered complementary if they are standardized to the objectives of the study. The use of pitfall traps in short-term surveys of the snake fauna in areas with shrubby vegetation and stony soil is not recommended.

  3. Standard methods for sampling North American freshwater fishes

    Science.gov (United States)

    Bonar, Scott A.; Hubert, Wayne A.; Willis, David W.

    2009-01-01

    This important reference book provides standard sampling methods recommended by the American Fisheries Society for assessing and monitoring freshwater fish populations in North America. Methods apply to ponds, reservoirs, natural lakes, and streams and rivers containing cold and warmwater fishes. Range-wide and eco-regional averages for indices of abundance, population structure, and condition for individual species are supplied to facilitate comparisons of standard data among populations. Provides information on converting nonstandard to standard data, statistical and database procedures for analyzing and storing standard data, and methods to prevent transfer of invasive species while sampling.

  4. A multi-dimensional sampling method for locating small scatterers

    International Nuclear Information System (INIS)

    Song, Rencheng; Zhong, Yu; Chen, Xudong

    2012-01-01

    A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method. (paper)

  5. Advanced Markov chain Monte Carlo methods learning from past samples

    CERN Document Server

    Liang, Faming; Carrol, Raymond J

    2010-01-01

    This book provides comprehensive coverage of simulation of complex systems using Monte Carlo methods. Developing algorithms that are immune to the local trap problem has long been considered as the most important topic in MCMC research. Various advanced MCMC algorithms which address this problem have been developed include, the modified Gibbs sampler, the methods based on auxiliary variables and the methods making use of past samples. The focus of this book is on the algorithms that make use of past samples. This book includes the multicanonical algorithm, dynamic weighting, dynamically weight

  6. The influence of connectivity in forest patches, and riparian vegetation width on stream macroinvertebrate fauna

    Directory of Open Access Journals (Sweden)

    IC Valle

    Full Text Available We assessed two dimensions of stream connectivity: longitudinal (between forest patches along the stream and lateral (riparian vegetation, using macroinvertebrate assemblages as bioindicators. Sites representing different land-uses were sampled in a lowland basin that holds a mosaic of protected areas. Land-use analysis, forest successional stages and riparian zone widths were calculated by the GIS analysis. Macroinvertebrate fauna was strongly affected by land-use. We observed a continuous decrease in the number of sensitive species, %Shredders and IBE-IOC biotic index from the upstream protected area to highly deforested sites, increasing again where the stream crosses a Biological Reserve. When analysing buffer strips, we found aquatic fauna responding to land-use alterations beyond the 30 m riparian corridor (60 m and 100 m wide. We discussed the longitudinal connectivity between forest patches and the riparian vegetation buffer strips necessary to hold high macroinvertebrate diversity. We recommend actions for the increase/maintenance of biodiversity in this and other lowland basins.

  7. Development of sample preparation method for honey analysis using PIXE

    International Nuclear Information System (INIS)

    Saitoh, Katsumi; Chiba, Keiko; Sera, Koichiro

    2008-01-01

    We developed an original preparation method for honey samples (samples in paste-like state) specifically designed for PIXE analysis. The results of PIXE analysis of thin targets prepared by adding a standard containing nine elements to honey samples demonstrated that the preparation method bestowed sufficient accuracy on quantitative values. PIXE analysis of 13 kinds of honey was performed, and eight mineral components (Si, P, S, K, Ca, Mn, Cu and Zn) were detected in all honey samples. The principal mineral components were K and Ca, and the quantitative value for K accounted for the majority of the total value for mineral components. K content in honey varies greatly depending on the plant source. Chestnuts had the highest K content. In fact, it was 2-3 times that of Manuka, which is known as a high quality honey. K content of false-acacia, which is produced in the greatest abundance, was 1/20 that of chestnuts. (author)

  8. Validation of single-sample doubly labeled water method

    International Nuclear Information System (INIS)

    Webster, M.D.; Weathers, W.W.

    1989-01-01

    We have experimentally validated a single-sample variant of the doubly labeled water method for measuring metabolic rate and water turnover in a very small passerine bird, the verdin (Auriparus flaviceps). We measured CO 2 production using the Haldane gravimetric technique and compared these values with estimates derived from isotopic data. Doubly labeled water results based on the one-sample calculations differed from Haldane values by less than 0.5% on average (range -8.3 to 11.2%, n = 9). Water flux computed by the single-sample method differed by -1.5% on average from results for the same birds based on the standard, two-sample technique (range -13.7 to 2.0%, n = 9)

  9. Examination of Hydrate Formation Methods: Trying to Create Representative Samples

    Energy Technology Data Exchange (ETDEWEB)

    Kneafsey, T.J.; Rees, E.V.L.; Nakagawa, S.; Kwon, T.-H.

    2011-04-01

    Forming representative gas hydrate-bearing laboratory samples is important so that the properties of these materials may be measured, while controlling the composition and other variables. Natural samples are rare, and have often experienced pressure and temperature changes that may affect the property to be measured [Waite et al., 2008]. Forming methane hydrate samples in the laboratory has been done a number of ways, each having advantages and disadvantages. The ice-to-hydrate method [Stern et al., 1996], contacts melting ice with methane at the appropriate pressure to form hydrate. The hydrate can then be crushed and mixed with mineral grains under controlled conditions, and then compacted to create laboratory samples of methane hydrate in a mineral medium. The hydrate in these samples will be part of the load-bearing frame of the medium. In the excess gas method [Handa and Stupin, 1992], water is distributed throughout a mineral medium (e.g. packed moist sand, drained sand, moistened silica gel, other porous media) and the mixture is brought to hydrate-stable conditions (chilled and pressurized with gas), allowing hydrate to form. This method typically produces grain-cementing hydrate from pendular water in sand [Waite et al., 2004]. In the dissolved gas method [Tohidi et al., 2002], water with sufficient dissolved guest molecules is brought to hydrate-stable conditions where hydrate forms. In the laboratory, this is can be done by pre-dissolving the gas of interest in water and then introducing it to the sample under the appropriate conditions. With this method, it is easier to form hydrate from more soluble gases such as carbon dioxide. It is thought that this method more closely simulates the way most natural gas hydrate has formed. Laboratory implementation, however, is difficult, and sample formation is prohibitively time consuming [Minagawa et al., 2005; Spangenberg and Kulenkampff, 2005]. In another version of this technique, a specified quantity of gas

  10. Standard methods for sampling freshwater fishes: opportunities for international collaboration

    OpenAIRE

    Bonar, Scott A.; Mercado-Silva, Norman; Hubert, Wayne A.; Beard, T. Douglas; Dave, Göran; Kubečka, Jan; Graeb, Brian D.S.; Lester, Nigel P.; Porath, Mark; Winfield, Ian J.

    2017-01-01

    With publication of Standard Methods for Sampling North American Freshwater Fishes in 2009, the American Fisheries Society (AFS) recommended standard procedures for North America. To explore interest in standardizing at intercontinental scales, a symposium attended by international specialists in freshwater fish sampling was convened at the 145th Annual AFS Meeting in Portland, Oregon, in August 2015. Participants represented all continents except Australia and Antarctica and were employed by...

  11. Characterizing lentic freshwater fish assemblages using multiple sampling methods

    Science.gov (United States)

    Fischer, Jesse R.; Quist, Michael C.

    2014-01-01

    Characterizing fish assemblages in lentic ecosystems is difficult, and multiple sampling methods are almost always necessary to gain reliable estimates of indices such as species richness. However, most research focused on lentic fish sampling methodology has targeted recreationally important species, and little to no information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterizing entire fish assemblages. Therefore, six lakes and impoundments (48–1,557 ha surface area) were sampled seasonally with seven gear types to evaluate the combined influence of sampling methods and timing on the number of species and individuals sampled. Probabilities of detection for species indicated strong selectivities and seasonal trends that provide guidance on optimal seasons to use gears when targeting multiple species. The evaluation of species richness and number of individuals sampled using multiple gear combinations demonstrated that appreciable benefits over relatively few gears (e.g., to four) used in optimal seasons were not present. Specifically, over 90 % of the species encountered with all gear types and season combinations (N = 19) from six lakes and reservoirs were sampled with nighttime boat electrofishing in the fall and benthic trawling, modified-fyke, and mini-fyke netting during the summer. Our results indicated that the characterization of lentic fish assemblages was highly influenced by the selection of sampling gears and seasons, but did not appear to be influenced by waterbody type (i.e., natural lake, impoundment). The standardization of data collected with multiple methods and seasons to account for bias is imperative to monitoring of lentic ecosystems and will provide researchers with increased reliability in their interpretations and decisions made using information on lentic fish assemblages.

  12. Fluidics platform and method for sample preparation and analysis

    Science.gov (United States)

    Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

    2014-08-19

    Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

  13. Adaptive sampling method in deep-penetration particle transport problem

    International Nuclear Information System (INIS)

    Wang Ruihong; Ji Zhicheng; Pei Lucheng

    2012-01-01

    Deep-penetration problem has been one of the difficult problems in shielding calculation with Monte Carlo method for several decades. In this paper, a kind of particle transport random walking system under the emission point as a sampling station is built. Then, an adaptive sampling scheme is derived for better solution with the achieved information. The main advantage of the adaptive scheme is to choose the most suitable sampling number from the emission point station to obtain the minimum value of the total cost in the process of the random walk. Further, the related importance sampling method is introduced. Its main principle is to define the importance function due to the particle state and to ensure the sampling number of the emission particle is proportional to the importance function. The numerical results show that the adaptive scheme under the emission point as a station could overcome the difficulty of underestimation of the result in some degree, and the adaptive importance sampling method gets satisfied results as well. (authors)

  14. Methods for Sampling and Measurement of Compressed Air Contaminants

    International Nuclear Information System (INIS)

    Stroem, L.

    1976-10-01

    In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

  15. Methods for Sampling and Measurement of Compressed Air Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Stroem, L

    1976-10-15

    In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

  16. Sampling and sample preparation methods for the analysis of trace elements in biological material

    International Nuclear Information System (INIS)

    Sansoni, B.; Iyengar, V.

    1978-05-01

    The authors attempt to give a most systamtic possible treatment of the sample taking and sample preparation of biological material (particularly in human medicine) for trace analysis (e.g. neutron activation analysis, atomic absorption spectrometry). Contamination and loss problems are discussed as well as the manifold problems of the different consistency of solid and liquid biological materials, as well as the stabilization of the sample material. The process of dry and wet ashing is particularly dealt with, where new methods are also described. (RB) [de

  17. An algorithm to improve sampling efficiency for uncertainty propagation using sampling based method

    International Nuclear Information System (INIS)

    Campolina, Daniel; Lima, Paulo Rubens I.; Pereira, Claubia; Veloso, Maria Auxiliadora F.

    2015-01-01

    Sample size and computational uncertainty were varied in order to investigate sample efficiency and convergence of the sampling based method for uncertainty propagation. Transport code MCNPX was used to simulate a LWR model and allow the mapping, from uncertain inputs of the benchmark experiment, to uncertain outputs. Random sampling efficiency was improved through the use of an algorithm for selecting distributions. Mean range, standard deviation range and skewness were verified in order to obtain a better representation of uncertainty figures. Standard deviation of 5 pcm in the propagated uncertainties for 10 n-samples replicates was adopted as convergence criterion to the method. Estimation of 75 pcm uncertainty on reactor k eff was accomplished by using sample of size 93 and computational uncertainty of 28 pcm to propagate 1σ uncertainty of burnable poison radius. For a fixed computational time, in order to reduce the variance of the uncertainty propagated, it was found, for the example under investigation, it is preferable double the sample size than double the amount of particles followed by Monte Carlo process in MCNPX code. (author)

  18. Evaluation of Macroinvertebrate Data Based on Autoecological Information

    Directory of Open Access Journals (Sweden)

    Juhász I.

    2016-12-01

    Full Text Available Various data (biological, chemical, hydrological and morphological have been gathered within the frame of the monitoring of the Water Framework Directive from 2007 in Hungary. This data only used a status assessment of certain water bodies in Hungary. The macroinvertebrates indicate many environmental factors well; therefore, they are very useful in detecting changes in the status of an environment. The main aim in this research was to investigate changes in environmental variables and decide how these variables cause big changes in the macroinvertebrate fauna. The macroinvertebrate data was processed using the ASTERICS 4.0.4 program. The program calculated some important metrics (i.e., microhabitat distributions, longitudinal zonation, functional feeding guilds, etc.. These metrics were compared with the chemical and hydrological data. The main conclusion is that if we have enough of a frequency and quality of macroinvertebrate data, we can understand changes in the environment of an ecosystem.

  19. Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods

    International Nuclear Information System (INIS)

    Chady, T.

    2004-01-01

    In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials' properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by scanning the surface of the specimens with GMR gradiometer. Next, the same samples were evaluated using an eddy current sensor. A comparison between results obtained from both methods was carried out. Finally, selected parameters of the measured signal were calculated and utilized to evaluate level of the applied stress. A strong coincidence between amount of the applied stress and the maximum amplitude of the derivative was confirmed

  20. On the Exploitation of Sensitivity Derivatives for Improving Sampling Methods

    Science.gov (United States)

    Cao, Yanzhao; Hussaini, M. Yousuff; Zang, Thomas A.

    2003-01-01

    Many application codes, such as finite-element structural analyses and computational fluid dynamics codes, are capable of producing many sensitivity derivatives at a small fraction of the cost of the underlying analysis. This paper describes a simple variance reduction method that exploits such inexpensive sensitivity derivatives to increase the accuracy of sampling methods. Three examples, including a finite-element structural analysis of an aircraft wing, are provided that illustrate an order of magnitude improvement in accuracy for both Monte Carlo and stratified sampling schemes.

  1. [Progress in sample preparation and analytical methods for trace polar small molecules in complex samples].

    Science.gov (United States)

    Zhang, Qianchun; Luo, Xialin; Li, Gongke; Xiao, Xiaohua

    2015-09-01

    Small polar molecules such as nucleosides, amines, amino acids are important analytes in biological, food, environmental, and other fields. It is necessary to develop efficient sample preparation and sensitive analytical methods for rapid analysis of these polar small molecules in complex matrices. Some typical materials in sample preparation, including silica, polymer, carbon, boric acid and so on, are introduced in this paper. Meanwhile, the applications and developments of analytical methods of polar small molecules, such as reversed-phase liquid chromatography, hydrophilic interaction chromatography, etc., are also reviewed.

  2. Differences found in the macroinvertebrate community composition in the presence or absence of the invasive alien crayfish, Orconectes hylas

    Science.gov (United States)

    Freeland-Riggert, Brandye T.; Cairns, Stefan H.; Poulton, Barry C.; Riggert, Chris M.

    2016-01-01

    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities.

  3. Macroinvertebrate communities associated with littoral zone habitats and the influence of environmental factors in Malilangwe Reservoir, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Dalu T.

    2012-10-01

    Full Text Available The aim of our study was to investigate macroinvertebrate communities so as to understand factors and processes structuring macroinvertebrate communities in a small reservoir, Malilangwe reservoir over seven months (April to October. Sampling was performed by active sweep netting and searching soil sediments. Water temperature, conductivity, dissolved oxygen, pH, ammonia, nitrogen, phosphorus, chemical oxygen demand and macrophyte cover were determined. In total, forty-two macroinvertebrate families belonging to 10 orders were identified amongst 13 macrophyte species and sediments. Thiaridae and Physidae (Mollusca were the dominant and most abundant taxa (57.71% and there were followed by the Hemiptera (27.31%. High indices for sites 1 to 3 for the Simpsons index, the Shannon-Weaver index and evenness were recorded, while low indices were observed for sites 4 to 5, with significant differences being observed among the study site using the Kruskal-Wallis ANOVA test (p < 0.05. Redundancy Analysis revealed that among environmental factors, hydrologically linked parameters such as conductivity, water level and macrophyte cover had the strongest influence on macroinvertebrate distribution.

  4. Hydrologic controls on basin-scale distribution of benthic macroinvertebrates

    Science.gov (United States)

    Bertuzzo, E.; Ceola, S.; Singer, G. A.; Battin, T. J.; Montanari, A.; Rinaldo, A.

    2013-12-01

    The presentation deals with the role of streamflow variability on basin-scale distributions of benthic macroinvertebrates. Specifically, we present a probabilistic analysis of the impacts of the variability along the river network of relevant hydraulic variables on the density of benthic macroinvertebrate species. The relevance of this work is based on the implications of the predictability of macroinvertebrate patterns within a catchment on fluvial ecosystem health, being macroinvertebrates commonly used as sensitive indicators, and on the effects of anthropogenic activity. The analytical tools presented here outline a novel procedure of general nature aiming at a spatially-explicit quantitative assessment of how near-bed flow variability affects benthic macroinvertebrate abundance. Moving from the analytical characterization of the at-a-site probability distribution functions (pdfs) of streamflow and bottom shear stress, a spatial extension to a whole river network is performed aiming at the definition of spatial maps of streamflow and bottom shear stress. Then, bottom shear stress pdf, coupled with habitat suitability curves (e.g., empirical relations between species density and bottom shear stress) derived from field studies are used to produce maps of macroinvertebrate suitability to shear stress conditions. Thus, moving from measured hydrologic conditions, possible effects of river streamflow alterations on macroinvertebrate densities may be fairly assessed. We apply this framework to an Austrian river network, used as benchmark for the analysis, for which rainfall and streamflow time-series and river network hydraulic properties and macroinvertebrate density data are available. A comparison between observed vs "modeled" species' density in three locations along the examined river network is also presented. Although the proposed approach focuses on a single controlling factor, it shows important implications with water resources management and fluvial

  5. Estimation of creatinine in Urine sample by Jaffe's method

    International Nuclear Information System (INIS)

    Wankhede, Sonal; Arunkumar, Suja; Sawant, Pramilla D.; Rao, B.B.

    2012-01-01

    In-vitro bioassay monitoring is based on the determination of activity concentrations in biological samples excreted from the body and is most suitable for alpha and beta emitters. A truly representative bioassay sample is the one having all the voids collected during a 24-h period however, this being technically difficult, overnight urine samples collected by the workers are analyzed. These overnight urine samples are collected for 10-16 h, however in the absence of any specific information, 12 h duration is assumed and the observed results are then corrected accordingly obtain the daily excretion rate. To reduce the uncertainty due to unknown duration of sample collection, IAEA has recommended two methods viz., measurement of specific gravity and creatinine excretion rate in urine sample. Creatinine is a final metabolic product creatinine phosphate in the body and is excreted at a steady rate for people with normally functioning kidneys. It is, therefore, often used as a normalization factor for estimation of duration of sample collection. The present study reports the chemical procedure standardized and its application for the estimation of creatinine in urine samples collected from occupational workers. Chemical procedure for estimation of creatinine in bioassay samples was standardized and applied successfully for its estimation in bioassay samples collected from the workers. The creatinine excretion rate observed for these workers is lower than observed in literature. Further, work is in progress to generate a data bank of creatinine excretion rate for most of the workers and also to study the variability in creatinine coefficient for the same individual based on the analysis of samples collected for different duration

  6. Sampling methods for low-frequency electromagnetic imaging

    International Nuclear Information System (INIS)

    Gebauer, Bastian; Hanke, Martin; Schneider, Christoph

    2008-01-01

    For the detection of hidden objects by low-frequency electromagnetic imaging the linear sampling method works remarkably well despite the fact that the rigorous mathematical justification is still incomplete. In this work, we give an explanation for this good performance by showing that in the low-frequency limit the measurement operator fulfils the assumptions for the fully justified variant of the linear sampling method, the so-called factorization method. We also show how the method has to be modified in the physically relevant case of electromagnetic imaging with divergence-free currents. We present numerical results to illustrate our findings, and to show that similar performance can be expected for the case of conducting objects and layered backgrounds

  7. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Science.gov (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  8. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Matthias, E-mail: matthias.schindler@physik.uni-erlangen.de; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-15

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO{sub 2} and reduced to graphite to determine {sup 14}C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  9. Responses of aquatic organisms to metal pollution in a lowland river in Flanders: A comparison of diatoms and macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Jonge, Maarten de [Department of Biology, Ecophysiology, Biochemistry and Toxicology Group, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)], E-mail: maarten.dejonge@ua.ac.be; Vijver, Bart van de [Department of Bryophytes and Thallophytes, National Botanic Garden of Belgium, Domein van Bouchout, 1860 Meise (Belgium); Blust, Ronny; Bervoets, Lieven [Department of Biology, Ecophysiology, Biochemistry and Toxicology Group, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2008-12-15

    The role of macroinvertebrates and diatoms as indicator for metal pollution was investigated by assessing both biota along a metal gradient in the Belgian river the Dommel. Macroinvertebrates and diatoms were sampled in summer and winter and physical-chemical characteristics of the water were measured at four different sample periods and related to sediment characteristics. Although metal concentrations, except cadmium, in the water nowhere exceeded water quality standards, high metal concentrations were measured in the sediment, indicating historical contamination of the Dommel. At the sites that were situated downstream of the pollution source, high levels of conductivity and chloride were measured in the water. Redundancy Analysis (RDA) indicated pH, phosphate and zinc as the significant environmental variables explaining each respectively 7.7%, 11.6% and 22.6% of the macroinvertebrate community composition. Two clusters could be separated, with Gammarus pulex, Leptocerus interruptus, Baetis rhodani and Cloeon dipterum associated with low zinc concentrations and Tubificidae, Asellus aquaticus, Erpobdella sp. and Chironomus thummi-plumosus associated with higher zinc concentrations. Ammonium (10.6%), conductivity (16.5%), chloride (11.4%) and zinc (5.9%) turned out to be significant variables explaining the diatom community structure. Based on physical-chemical differences and species composition, three different groups could be separated. With this Tabellaria flocculosa and Fragilaria capucina var. rumpens were associated with low metal concentrations, Gomphonema parvulum and Nitzschia palea with elevated concentrations and Eolimna minima and Sellaphora seminulum with high zinc concentrations. In conclusion, the diatom community best reflected the metal gradient. With regard to water quality indices, those based on macroinvertebrates best followed the metal pollution gradient and were most strongly correlated with physical-chemical variables of water and

  10. Responses of aquatic organisms to metal pollution in a lowland river in Flanders: A comparison of diatoms and macroinvertebrates

    International Nuclear Information System (INIS)

    Jonge, Maarten de; Vijver, Bart van de; Blust, Ronny; Bervoets, Lieven

    2008-01-01

    The role of macroinvertebrates and diatoms as indicator for metal pollution was investigated by assessing both biota along a metal gradient in the Belgian river the Dommel. Macroinvertebrates and diatoms were sampled in summer and winter and physical-chemical characteristics of the water were measured at four different sample periods and related to sediment characteristics. Although metal concentrations, except cadmium, in the water nowhere exceeded water quality standards, high metal concentrations were measured in the sediment, indicating historical contamination of the Dommel. At the sites that were situated downstream of the pollution source, high levels of conductivity and chloride were measured in the water. Redundancy Analysis (RDA) indicated pH, phosphate and zinc as the significant environmental variables explaining each respectively 7.7%, 11.6% and 22.6% of the macroinvertebrate community composition. Two clusters could be separated, with Gammarus pulex, Leptocerus interruptus, Baetis rhodani and Cloeon dipterum associated with low zinc concentrations and Tubificidae, Asellus aquaticus, Erpobdella sp. and Chironomus thummi-plumosus associated with higher zinc concentrations. Ammonium (10.6%), conductivity (16.5%), chloride (11.4%) and zinc (5.9%) turned out to be significant variables explaining the diatom community structure. Based on physical-chemical differences and species composition, three different groups could be separated. With this Tabellaria flocculosa and Fragilaria capucina var. rumpens were associated with low metal concentrations, Gomphonema parvulum and Nitzschia palea with elevated concentrations and Eolimna minima and Sellaphora seminulum with high zinc concentrations. In conclusion, the diatom community best reflected the metal gradient. With regard to water quality indices, those based on macroinvertebrates best followed the metal pollution gradient and were most strongly correlated with physical-chemical variables of water and

  11. Trophic relationships between macroinvertebrates and fish in a pampean lowland stream (Argentina

    Directory of Open Access Journals (Sweden)

    María V. López van Oosterom

    2013-03-01

    Full Text Available The diet and trophic relationships between the macroinvertebrates Phyllogomphoides joaquini Rodrigues Capítulo, 1992 and Coenagrionidae (Odonata, Chironomidae (Diptera, Diplodon delodontus (Lamarck, 1919 (Bivalvia: Hyriidae, and Pomacea canaliculata (Lamarck, 1822 (Gastropoda: Ampulariidae and the fishes Pimelodella laticeps Eigenmann, 1917 (Heptapteridae and Bryconamericus iheringii (Boulenger, 1887 (Characidae in a temperate lowland lotic system in Argentina were assessed on the basis of gut contents and stable-isotope analyses. The feeding strategies were analyzed by the AMUNDSEN method. Relative food items contribution for the taxa studied indicated a generalist-type trophic strategy. In macroinvertebrates, in general, the values of stable isotope confirmed the result of the analysis of gut contents. With the fish, stable-isotope analysis demonstrated that both species are predators, although B. iheringii exhibited a more omnivorous behaviour. These feeding studies allowed us to determine the trophic relationships among taxa studied. Detritus and diatoms were a principal source of food for all the macroinvertebrates studied. In La Choza stream the particulate organic matter is a major no limited food resource, has a significant influence upon the community.

  12. Relationships among rotational and conventional grazing systems, stream channels, and macroinvertebrates

    Science.gov (United States)

    Raymond, K.L.; Vondracek, B.

    2011-01-01

    Cattle grazing in riparian areas can reduce water quality, alter stream channel characteristics, and alter fish and macroinvertebrate assemblage structure. The U.S. Department of Agriculture, Natural Resources Conservation Services has recommended Rotational Grazing (RG) as an alternative management method on livestock and dairy operations to protect riparian areas and water quality. We evaluated 13 stream channel characteristics, benthic macroinvertebrate larvae (BML), and chironomid pupal exuviae (CPE) from 18 sites in the Upper Midwest of the United States in relation to RG and conventional grazing (CG). A Biotic Composite Score comprised of several macroinvertebrate metrics was developed for both the BML assemblage and the CPE assemblage. Multi-Response Permutation Procedures (MRPP) indicated a significant difference in stream channel characteristics between RG and CG. Nonmetric Multidimensional Scaling indicated that RG sites were associated with more stable stream banks, higher quality aquatic habitat, lower soil compaction, and larger particles in the streambed. However, neither MRPP nor Mann-Whitney U tests demonstrated a difference in Biotic Composite Scores for BML or CPE along RG and CG sites. The BML and CPE metrics were significantly correlated, indicating that they were likely responding to similar variables among the study sites. Although stream channel characteristics appeared to respond to grazing management, BML and CPE may have responded to land use throughout the watershed, as well as local land use. ?? 2011 Springer Science+Business Media B.V. (outside the USA).

  13. Methods for Characterisation of unknown Suspect Radioactive Samples

    International Nuclear Information System (INIS)

    Sahagia, M.; Grigorescu, E.L.; Luca, A.; Razdolescu, A.C.; Ivan, C.

    2001-01-01

    Full text: The paper presents various identification and measurement methods, used for the expertise of a wide variety of suspect radioactive materials, whose circulation was not legally stated. The main types of examined samples were: radioactive sources, illegally trafficked; suspect radioactive materials or radioactively contaminated devices; uranium tablets; fire detectors containing 241 Am sources; osmium samples containing radioactive 185 Os or enriched 187 Os. The types of analyses and determination methods were as follows: the chemical composition was determined by using identification reagents or by neutron activation analysis; the radionuclide composition was determined by using gamma-ray spectrometry; the activity and particle emission rates were determined by using calibrated radiometric equipment; the absorbed dose rate at the wall of all types of containers and samples was determined by using calibrated dose ratemeters. The radiation exposure risk for population, due to these radioactive materials, was evaluated for every case. (author)

  14. Sampling and analysis methods for geothermal fluids and gases

    Energy Technology Data Exchange (ETDEWEB)

    Shannon, D. W.

    1978-01-01

    The data obtained for the first round robin sample collected at Mesa 6-2 wellhead, East Mesa Test Site, Imperial Valley are summarized. Test results are listed by method used for cross reference to the analytic methods section. Results obtained for radioactive isotopes present in the brine sample are tabulated. The data obtained for the second round robin sample collected from the Woolsey No. 1 first stage flash unit, San Diego Gas and Electric Niland Test Facility are presented in the same manner. Lists of the participants of the two round robins are given. Data from miscellaneous analyses are included. Summaries of values derived from the round robin raw data are presented. (MHR)

  15. Microbial diversity in fecal samples depends on DNA extraction method

    DEFF Research Database (Denmark)

    Mirsepasi, Hengameh; Persson, Søren; Struve, Carsten

    2014-01-01

    was to evaluate two different DNA extraction methods in order to choose the most efficient method for studying intestinal bacterial diversity using Denaturing Gradient Gel Electrophoresis (DGGE). FINDINGS: In this study, a semi-automatic DNA extraction system (easyMag®, BioMérieux, Marcy I'Etoile, France......BACKGROUND: There are challenges, when extracting bacterial DNA from specimens for molecular diagnostics, since fecal samples also contain DNA from human cells and many different substances derived from food, cell residues and medication that can inhibit downstream PCR. The purpose of the study...... by easyMag® from the same fecal samples. Furthermore, DNA extracts obtained using easyMag® seemed to contain inhibitory compounds, since in order to perform a successful PCR-analysis, the sample should be diluted at least 10 times. DGGE performed on PCR from DNA extracted by QIAamp DNA Stool Mini Kit DNA...

  16. A Frequency Domain Design Method For Sampled-Data Compensators

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Jannerup, Ole Erik

    1990-01-01

    A new approach to the design of a sampled-data compensator in the frequency domain is investigated. The starting point is a continuous-time compensator for the continuous-time system which satisfy specific design criteria. The new design method will graphically show how the discrete...

  17. Phosphorus analysis in milk samples by neutron activation analysis method

    International Nuclear Information System (INIS)

    Oliveira, R.M. de; Cunha, I.I.L.

    1991-01-01

    The determination of phosphorus in milk samples by instrumental thermal neutron activation analysis is described. The procedure involves a short irradiation in a nuclear reactor and measurement of the beta radiation emitted by phosphorus - 32 after a suitable decay period. The sources of error were studied and the established method was applied to standard reference materials of known phosphorus content. (author)

  18. Sampling point selection for energy estimation in the quasicontinuum method

    NARCIS (Netherlands)

    Beex, L.A.A.; Peerlings, R.H.J.; Geers, M.G.D.

    2010-01-01

    The quasicontinuum (QC) method reduces computational costs of atomistic calculations by using interpolation between a small number of so-called repatoms to represent the displacements of the complete lattice and by selecting a small number of sampling atoms to estimate the total potential energy of

  19. A General Linear Method for Equating with Small Samples

    Science.gov (United States)

    Albano, Anthony D.

    2015-01-01

    Research on equating with small samples has shown that methods with stronger assumptions and fewer statistical estimates can lead to decreased error in the estimated equating function. This article introduces a new approach to linear observed-score equating, one which provides flexible control over how form difficulty is assumed versus estimated…

  20. Performance of sampling methods to estimate log characteristics for wildlife.

    Science.gov (United States)

    Lisa J. Bate; Torolf R. Torgersen; Michael J. Wisdom; Edward O. Garton

    2004-01-01

    Accurate estimation of the characteristics of log resources, or coarse woody debris (CWD), is critical to effective management of wildlife and other forest resources. Despite the importance of logs as wildlife habitat, methods for sampling logs have traditionally focused on silvicultural and fire applications. These applications have emphasized estimates of log volume...

  1. Effect of method of sample preparation on ruminal in situ ...

    African Journals Online (AJOL)

    Midmar) was harvested at three and four weeks after cutting and fertilizing with 200 kg nitrogen (N)/ha. Freshly cut herbage was used to investigate the following four sample preparation methods. In trial 1, herbage was (1) chopped with a paper-cutting guillotine into 5-10 mm lengths, representing fresh (FR) herbage; ...

  2. Assessment of water chemistry, habitat, and benthic macroinvertebrates at selected stream-quality monitoring sites in Chester County, Pennsylvania, 1998-2000

    Science.gov (United States)

    Reif, Andrew G.

    2004-01-01

    Biological, chemical, and habitat data have been collected from a network of sites in Chester County, Pa., from 1970 to 2003 to assess stream quality. Forty sites in 6 major stream basins were sampled between 1998 and 2000. Biological data were used to determine levels of impairment in the benthic-macroinvertebrate community in Chester County streams and relate the impairment, in conjunction with chemical and habitat data, to overall stream quality. Biological data consisted of benthic-macroinvertebrate samples that were collected annually in the fall. Water-chemistry samples were collected and instream habitat was assessed in support of the biological sampling.Most sites in the network were designated as nonimpacted or slightly impacted by human activities or extreme climatic conditions on the basis of biological-metric analysis of benthic-macroinvertebrate data. Impacted sites were affected by factors, such as nutrient enrichment, erosion and sedimentation, point discharges, and droughts and floods. Streams in the Schuylkill River, Delaware River, and East Branch Brandywine Creek Basins in Chester County generally had low nutrient concentrations, except in areas affected by wastewater-treatment discharges, and stream habitat that was affected by erosion. Streams in the West Branch Brandywine, Christina, Big Elk, and Octoraro Creek Basins in Chester County generally had elevated nutrient concentrations and streambottom habitat that was affected by sediment deposition.Macroinvertebrate communities identified in samples from French Creek, Pigeon Creek (Schuylkill River Basin), and East Branch Brandywine Creek at Glenmoore consistently indicate good stream conditions and were the best conditions measured in the network. Macroinvertebrate communities identified in samples from Trout Creek (site 61), West Branch Red Clay Creek (site 55) (Christina River Basin), and Valley Creek near Atglen (site 34) (Octoraro Creek Basin) indicated fair to poor stream conditions and

  3. Sample processing method for the determination of perchlorate in milk

    International Nuclear Information System (INIS)

    Dyke, Jason V.; Kirk, Andrea B.; Kalyani Martinelango, P.; Dasgupta, Purnendu K.

    2006-01-01

    In recent years, many different water sources and foods have been reported to contain perchlorate. Studies indicate that significant levels of perchlorate are present in both human and dairy milk. The determination of perchlorate in milk is particularly important due to its potential health impact on infants and children. As for many other biological samples, sample preparation is more time consuming than the analysis itself. The concurrent presence of large amounts of fats, proteins, carbohydrates, etc., demands some initial cleanup; otherwise the separation column lifetime and the limit of detection are both greatly compromised. Reported milk processing methods require the addition of chemicals such as ethanol, acetic acid or acetonitrile. Reagent addition is undesirable in trace analysis. We report here an essentially reagent-free sample preparation method for the determination of perchlorate in milk. Milk samples are spiked with isotopically labeled perchlorate and centrifuged to remove lipids. The resulting liquid is placed in a disposable centrifugal ultrafilter device with a molecular weight cutoff of 10 kDa, and centrifuged. Approximately 5-10 ml of clear liquid, ready for analysis, is obtained from a 20 ml milk sample. Both bovine and human milk samples have been successfully processed and analyzed by ion chromatography-mass spectrometry (IC-MS). Standard addition experiments show good recoveries. The repeatability of the analytical result for the same sample in multiple sample cleanup runs ranged from 3 to 6% R.S.D. This processing technique has also been successfully applied for the determination of iodide and thiocyanate in milk

  4. Pesticides in agricultural headwater streams in southwestern Germany and effects on macroinvertebrate populations.

    Science.gov (United States)

    Weber, Gero; Christmann, Nicole; Thiery, Ann-Cathrin; Martens, Dieter; Kubiniok, Jochen

    2018-04-01

    Pesticides are a major burden for stream ecosystems in the central European cultivated landscape. The objective of the present study was to investigate the applicability of ecological indicator methods in relation to toxicity of pesticides under the specific hydro-morphological conditions in small water bodies. Thus, an association of toxicity evaluating methods with different ecological indicators was to be attempted. Based on three random samples taken within the 2016 vegetation period, 23 headwater areas in the Saarland were investigated to test for pesticides and their metabolites. The macroinvertebrate population was also surveyed in 16 of these streams. Evidence was found of 41 substances in total. Most dominant substances include atrazine, isoproturone, quinmerac and tebuconazol as well as metabolites of dimethenamid, chloridazon and metazachlor. At 9 of the 23 sampling points, over 10 plant protection products and metabolites were found. Only 17% of the water bodies investigated contained fewer than 5 substances. Around half of the bodies of water investigated show noticeably high concentrations of metabolites of plant protection products. Maximum concentrations exceeding environmental quality standards or the Health-oriented Guideline Values were measured for 13 substances at individual sampling points. Analysis of the biological data for only 4 of the water bodies investigated resulted in the Ecological Status Class (ESC) "good". All others fell short of the quality target, although they were classified as "good" or "very good" according to the Saprobic index. SPEAR pesticides as a measurement of the sensitivity of the biocoenosis to pesticides shows their influence in a few water bodies. Likewise, high toxic unit values have also been calculated, indicating the presence of toxic substances at relevant concentrations. However, an actual correlation between SPEAR pesticides and toxic unit could not be derived. Clearly in these very headwater streams other

  5. Optical methods for microstructure determination of doped samples

    Science.gov (United States)

    Ciosek, Jerzy F.

    2008-12-01

    The optical methods to determine refractive index profile of layered materials are commonly used with spectroscopic ellipsometry or transmittance/reflectance spectrometry. Measurements of spectral reflection and transmission usually permit to characterize optical materials and determine their refractive index. However, it is possible to characterize of samples with dopants, impurities as well as defects using optical methods. Microstructures of a hydrogenated crystalline Si wafer and a layer of SiO2 - ZrO2 composition are investigated. The first sample is a Si(001):H Czochralski grown single crystalline wafer with 50 nm thick surface Si02 layer. Hydrogen dose implantation (D continue to be an important issue in microelectronic device and sensor fabrication. Hydrogen-implanted silicon (Si: H) has become a topic of remarkable interest, mostly because of the potential of implantation-induced platelets and micro-cavities for the creation of gettering -active areas and for Si layer splitting. Oxygen precipitation and atmospheric impurity are analysed. The second sample is the layer of co-evaporated SiO2 and ZrO2 materials using simultaneously two electron beam guns in reactive evaporation methods. The composition structure was investigated by X-Ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry methods. A non-uniformity and composition of layer are analysed using average density method.

  6. Comparison of DNA preservation methods for environmental bacterial community samples.

    Science.gov (United States)

    Gray, Michael A; Pratte, Zoe A; Kellogg, Christina A

    2013-02-01

    Field collections of environmental samples, for example corals, for molecular microbial analyses present distinct challenges. The lack of laboratory facilities in remote locations is common, and preservation of microbial community DNA for later study is critical. A particular challenge is keeping samples frozen in transit. Five nucleic acid preservation methods that do not require cold storage were compared for effectiveness over time and ease of use. Mixed microbial communities of known composition were created and preserved by DNAgard(™), RNAlater(®), DMSO-EDTA-salt (DESS), FTA(®) cards, and FTA Elute(®) cards. Automated ribosomal intergenic spacer analysis and clone libraries were used to detect specific changes in the faux communities over weeks and months of storage. A previously known bias in FTA(®) cards that results in lower recovery of pure cultures of Gram-positive bacteria was also detected in mixed community samples. There appears to be a uniform bias across all five preservation methods against microorganisms with high G + C DNA. Overall, the liquid-based preservatives (DNAgard(™), RNAlater(®), and DESS) outperformed the card-based methods. No single liquid method clearly outperformed the others, leaving method choice to be based on experimental design, field facilities, shipping constraints, and allowable cost. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  7. Transuranic waste characterization sampling and analysis methods manual. Revision 1

    International Nuclear Information System (INIS)

    Suermann, J.F.

    1996-04-01

    This Methods Manual provides a unified source of information on the sampling and analytical techniques that enable Department of Energy (DOE) facilities to comply with the requirements established in the current revision of the Transuranic Waste Characterization Quality Assurance Program Plan (QAPP) for the Waste Isolation Pilot Plant (WIPP) Transuranic (TRU) Waste Characterization Program (the Program) and the WIPP Waste Analysis Plan. This Methods Manual includes all of the testing, sampling, and analytical methodologies accepted by DOE for use in implementing the Program requirements specified in the QAPP and the WIPP Waste Analysis Plan. The procedures in this Methods Manual are comprehensive and detailed and are designed to provide the necessary guidance for the preparation of site-specific procedures. With some analytical methods, such as Gas Chromatography/Mass Spectrometry, the Methods Manual procedures may be used directly. With other methods, such as nondestructive characterization, the Methods Manual provides guidance rather than a step-by-step procedure. Sites must meet all of the specified quality control requirements of the applicable procedure. Each DOE site must document the details of the procedures it will use and demonstrate the efficacy of such procedures to the Manager, National TRU Program Waste Characterization, during Waste Characterization and Certification audits

  8. Non-uniform sampling and wide range angular spectrum method

    International Nuclear Information System (INIS)

    Kim, Yong-Hae; Byun, Chun-Won; Oh, Himchan; Lee, JaeWon; Pi, Jae-Eun; Heon Kim, Gi; Lee, Myung-Lae; Ryu, Hojun; Chu, Hye-Yong; Hwang, Chi-Sun

    2014-01-01

    A novel method is proposed for simulating free space field propagation from a source plane to a destination plane that is applicable for both small and large propagation distances. The angular spectrum method (ASM) was widely used for simulating near field propagation, but it caused a numerical error when the propagation distance was large because of aliasing due to under sampling. Band limited ASM satisfied the Nyquist condition on sampling by limiting a bandwidth of a propagation field to avoid an aliasing error so that it could extend the applicable propagation distance of the ASM. However, the band limited ASM also made an error due to the decrease of an effective sampling number in a Fourier space when the propagation distance was large. In the proposed wide range ASM, we use a non-uniform sampling in a Fourier space to keep a constant effective sampling number even though the propagation distance is large. As a result, the wide range ASM can produce simulation results with high accuracy for both far and near field propagation. For non-paraxial wave propagation, we applied the wide range ASM to a shifted destination plane as well. (paper)

  9. Standard methods for sampling freshwater fishes: Opportunities for international collaboration

    Science.gov (United States)

    Bonar, Scott A.; Mercado-Silva, Norman; Hubert, Wayne A.; Beard, Douglas; Dave, Göran; Kubečka, Jan; Graeb, Brian D. S.; Lester, Nigel P.; Porath, Mark T.; Winfield, Ian J.

    2017-01-01

    With publication of Standard Methods for Sampling North American Freshwater Fishes in 2009, the American Fisheries Society (AFS) recommended standard procedures for North America. To explore interest in standardizing at intercontinental scales, a symposium attended by international specialists in freshwater fish sampling was convened at the 145th Annual AFS Meeting in Portland, Oregon, in August 2015. Participants represented all continents except Australia and Antarctica and were employed by state and federal agencies, universities, nongovernmental organizations, and consulting businesses. Currently, standardization is practiced mostly in North America and Europe. Participants described how standardization has been important for management of long-term data sets, promoting fundamental scientific understanding, and assessing efficacy of large spatial scale management strategies. Academics indicated that standardization has been useful in fisheries education because time previously used to teach how sampling methods are developed is now more devoted to diagnosis and treatment of problem fish communities. Researchers reported that standardization allowed increased sample size for method validation and calibration. Group consensus was to retain continental standards where they currently exist but to further explore international and intercontinental standardization, specifically identifying where synergies and bridges exist, and identify means to collaborate with scientists where standardization is limited but interest and need occur.

  10. Soybean yield modeling using bootstrap methods for small samples

    Energy Technology Data Exchange (ETDEWEB)

    Dalposso, G.A.; Uribe-Opazo, M.A.; Johann, J.A.

    2016-11-01

    One of the problems that occur when working with regression models is regarding the sample size; once the statistical methods used in inferential analyzes are asymptotic if the sample is small the analysis may be compromised because the estimates will be biased. An alternative is to use the bootstrap methodology, which in its non-parametric version does not need to guess or know the probability distribution that generated the original sample. In this work we used a set of soybean yield data and physical and chemical soil properties formed with fewer samples to determine a multiple linear regression model. Bootstrap methods were used for variable selection, identification of influential points and for determination of confidence intervals of the model parameters. The results showed that the bootstrap methods enabled us to select the physical and chemical soil properties, which were significant in the construction of the soybean yield regression model, construct the confidence intervals of the parameters and identify the points that had great influence on the estimated parameters. (Author)

  11. A novel method for fission product noble gas sampling

    International Nuclear Information System (INIS)

    Jain, S.K.; Prakash, Vivek; Singh, G.K.; Vinay, Kr.; Awsthi, A.; Bihari, K.; Joyson, R.; Manu, K.; Gupta, Ashok

    2008-01-01

    Noble gases occur to some extent in the Earth's atmosphere, but the concentrations of all but argon are exceedingly low. Argon is plentiful, constituting almost 1 % of the air. Fission Product Noble Gases (FPNG) are produced by nuclear fission and large parts of FPNG is produced in Nuclear reactions. FPNG are b-j emitters and contributing significantly in public dose. During normal operation of reactor release of FPNG is negligible but its release increases in case of fuel failure. Xenon, a member of FPNG family helps in identification of fuel failure and its extent in PHWRs. Due to above reasons it becomes necessary to assess the FPNG release during operation of NPPs. Presently used methodology of assessment of FPNG, at almost all power stations is Computer based gamma ray spectrometry. This provides fission product Noble gases nuclide identification through peak search of spectra. The air sample for the same is collected by grab sampling method, which has inherent disadvantages. An alternate method was developed at Rajasthan Atomic Power Station (RAPS) - 3 and 4 for assessment of FPNG, which uses adsorption phenomena for collection of air samples. This report presents details of sampling method for FPNG and noble gases in different systems of Nuclear Power Plant. (author)

  12. Analytic continuation of quantum Monte Carlo data. Stochastic sampling method

    Energy Technology Data Exchange (ETDEWEB)

    Ghanem, Khaldoon; Koch, Erik [Institute for Advanced Simulation, Forschungszentrum Juelich, 52425 Juelich (Germany)

    2016-07-01

    We apply Bayesian inference to the analytic continuation of quantum Monte Carlo (QMC) data from the imaginary axis to the real axis. Demanding a proper functional Bayesian formulation of any analytic continuation method leads naturally to the stochastic sampling method (StochS) as the Bayesian method with the simplest prior, while it excludes the maximum entropy method and Tikhonov regularization. We present a new efficient algorithm for performing StochS that reduces computational times by orders of magnitude in comparison to earlier StochS methods. We apply the new algorithm to a wide variety of typical test cases: spectral functions and susceptibilities from DMFT and lattice QMC calculations. Results show that StochS performs well and is able to resolve sharp features in the spectrum.

  13. Entropic sampling in the path integral Monte Carlo method

    International Nuclear Information System (INIS)

    Vorontsov-Velyaminov, P N; Lyubartsev, A P

    2003-01-01

    We have extended the entropic sampling Monte Carlo method to the case of path integral representation of a quantum system. A two-dimensional density of states is introduced into path integral form of the quantum canonical partition function. Entropic sampling technique within the algorithm suggested recently by Wang and Landau (Wang F and Landau D P 2001 Phys. Rev. Lett. 86 2050) is then applied to calculate the corresponding entropy distribution. A three-dimensional quantum oscillator is considered as an example. Canonical distributions for a wide range of temperatures are obtained in a single simulation run, and exact data for the energy are reproduced

  14. Rapid screening method for plutonium in mixed waste samples

    International Nuclear Information System (INIS)

    Somers, W.; Culp, T.; Miller, R.

    1987-01-01

    A waste stream sampling program was undertaken to determine those waste streams which contained hazardous constituents, and would therefore be regulated as a hazardous waste under the Resource Conservation and Recovery Act. The waste streams also had the potential of containing radioactive material, either plutonium, americium, or depleted uranium. Because of the potential for contamination with radioactive material, a method of rapidly screening the liquid samples for radioactive material was required. A counting technique was devised to count a small aliquot of a sample, determine plutonium concentration, and allow the sample to be shipped the same day they were collected. This technique utilized the low energy photons (x-rays) that accompany α decay. This direct, non-destructive x-ray analysis was applied to quantitatively determine Pu-239 concentrations in industrial samples. Samples contained a Pu-239, Am-241 mixture; the ratio and/or concentrations of these two radionuclides was not constant. A computer program was designed and implemented to calculate Pu-239 activity and concentration (g/ml) using the 59.5 keV Am-241 peak to determine Am-241's contribution to the 17 keV region. Am's contribution was subtracted, yielding net counts in the 17 keV region due to Pu. 2 figs., 1 tab

  15. A method for sampling microbial aerosols using high altitude balloons.

    Science.gov (United States)

    Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C

    2014-12-01

    Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. A Method for Choosing the Best Samples for Mars Sample Return.

    Science.gov (United States)

    Gordon, Peter R; Sephton, Mark A

    2018-05-01

    Success of a future Mars Sample Return mission will depend on the correct choice of samples. Pyrolysis-FTIR can be employed as a triage instrument for Mars Sample Return. The technique can thermally dissociate minerals and organic matter for detection. Identification of certain mineral types can determine the habitability of the depositional environment, past or present, while detection of organic matter may suggest past or present habitation. In Mars' history, the Theiikian era represents an attractive target for life search missions and the acquisition of samples. The acidic and increasingly dry Theiikian may have been habitable and followed a lengthy neutral and wet period in Mars' history during which life could have originated and proliferated to achieve relatively abundant levels of biomass with a wide distribution. Moreover, the sulfate minerals produced in the Theiikian are also known to be good preservers of organic matter. We have used pyrolysis-FTIR and samples from a Mars analog ferrous acid stream with a thriving ecosystem to test the triage concept. Pyrolysis-FTIR identified those samples with the greatest probability of habitability and habitation. A three-tier scoring system was developed based on the detection of (i) organic signals, (ii) carbon dioxide and water, and (iii) sulfur dioxide. The presence of each component was given a score of A, B, or C depending on whether the substance had been detected, tentatively detected, or not detected, respectively. Single-step (for greatest possible sensitivity) or multistep (for more diagnostic data) pyrolysis-FTIR methods informed the assignments. The system allowed the highest-priority samples to be categorized as AAA (or A*AA if the organic signal was complex), while the lowest-priority samples could be categorized as CCC. Our methods provide a mechanism with which to rank samples and identify those that should take the highest priority for return to Earth during a Mars Sample Return mission. Key Words

  17. Application of Water Quality and Ecology Indices of Benthic Macroinvertebrate to Evaluate Water Quality of Tertiary Irrigation in Malang District

    Directory of Open Access Journals (Sweden)

    Desi Kartikasari

    2013-12-01

    Full Text Available This research aims to determine the water quality of tertiary irrigation in several subdistricts in Malang, namely Kepanjen, Karangploso, and Tumpang. The water quality depends on the water quality indices (National Sanitation Foundation’s-NSF Indices and O’Connor’s Indices based on variables TSS, TDS, pH, DO, and Nitrate concentrate and ecological indices of benthic macroinvertebrate (Diversity Indices Shannon-Wiener, Hilsenhof Biotic Indices-HBI, Average Score per Taxon-ASPT which is calculated by Biological Monitoring Working Party-BMWP, Ephemeroptera Indices, Plecoptera, Trichoptera-EPT. Observation of the physico-chemical water quality and benthic macroinvertebrate on May 2012 to April 2013. The sampling in each subdistrict was done at two selected stations in tertiary irrigation channel with three plot at each station. The data of physico-chemical quality of water were used to calculate the water quality indices, while the benthic macroinvertebrate data were used to calculate the ecological indices. The research findings showed that 27 taxa of benthic macroinvertebrates belong 10 classes were found in the three subdistrict. The pH, DO, Nitrate, TSS and TDS in six tertiary irrigation channels in Malang still met the water quality standards based on Government Regulation No. 82 of 2001 on Management of Water Quality and Water Pollution Control Class III. Based on NSF-WQI indices and O'Connor's Indices, water qualities in these irrigation channels were categorized into medium or moderate (yellow to good (green category. However, based on benthic macroinvertebrate communities which was used to determine the HBI, the water quality in the irrigation channels were categorized into the fair category (fairly significant organic pollution to fairly poor (significant organic pollution, while based on the value of ASPT, the water were categorized into probable moderate pollution to probable severe pollution. The irrigation water which was

  18. Analysis of benthic macroinvertebrates and biotic indices to evaluate water quality in rivers impacted by mining activities in northern Chile

    Directory of Open Access Journals (Sweden)

    Alvial I.E.

    2013-02-01

    Full Text Available Catchments in the semiarid regions are especially susceptible to environmental perturbation associated with water scarcity, hydrological variations and overuse by anthropogenic activities. Using multivariate analysis to relate environmental and biological data, and diversity and biotic indices (ChBMWP, ChIBF, we analyzed the macroinvertebrate composition of 12 rivers of the semiarid region of northern Chile. A non-metric multidimensional scaling for macroinvertebrate taxa and a principal component analysis for environmental variables strongly separated upstream sites (e.g. Vacas Heladas and Malo Rivers, which presented low pH and high dissolved metal concentrations, from other sites. Effectively, CCA showed that metals and low pH, associated with the altitudinal gradient, determined the distributional patterns of macroinvertebrates in the Elqui catchment. The causes of these particular conditions could be related to geological processes and human impact. The biotic indices applied to the sampling sites corroborated and reflected these characteristics, with La Laguna and Turbio Rivers showing a diverse macroinvertebrate community and moderate to good water quality, and the Claro River showing favorable conditions for the development of aquatic biota, indicating its better quality relative to other stations. To the middle and low part of the basin, a change in the composition of the community was observed, with species that suggest an impact by an increase in organic matter, due to agricultural activities and urban settlements concentrated in this area. Our results suggest that macroinvertebrate taxa in northern Chile may be exceptional species, adapted to unfavorable geochemical conditions, and emphasize the need for protection of the semiarid basins of the region.

  19. Cryptic biodiversity in streams: a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications

    Science.gov (United States)

    Species-level identifications are difficult or impossible for many larval aquatic macroinvertebrates. We described the taxonomic composition of macroinvertebrate communities from 5 coastal streams in 3 neighboring catchments in southern California. We compared taxonomic identific...

  20. Cryptic biodiversity in streams - a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications

    Science.gov (United States)

    Aquatic ecologists and entomologists have long known that species-level identifications were difficult, if not impossible, for many larval macroinvertebrates collected in streams. This study describes macroinvertebrate (primarily insect) communities from five coastal streams dist...

  1. Guam Community Coral Reef Monitoring Program, Macroinvertebrate Training Surveys in Guam in 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Guam community members gathered macroinvertebrate within a 25-meter x 2-meter belt transect. Members identified macroinvertebrates to species (when possible),...

  2. Empirical method for matrix effects correction in liquid samples

    International Nuclear Information System (INIS)

    Vigoda de Leyt, Dora; Vazquez, Cristina

    1987-01-01

    A simple method for the determination of Cr, Ni and Mo in stainless steels is presented. In order to minimize the matrix effects, the conditions of liquid system to dissolve stainless steels chips has been developed. Pure element solutions were used as standards. Preparation of synthetic solutions with all the elements of steel and also mathematic corrections are avoided. It results in a simple chemical operation which simplifies the method of analysis. The variance analysis of the results obtained with steel samples show that the three elements may be determined from the comparison with the analytical curves obtained with the pure elements if the same parameters in the calibration curves are used. The accuracy and the precision were checked against other techniques using the British Chemical Standards of the Bureau of Anlysed Samples Ltd. (England). (M.E.L.) [es

  3. Harmonisation of microbial sampling and testing methods for distillate fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hill, G.C.; Hill, E.C. [ECHA Microbiology Ltd., Cardiff (United Kingdom)

    1995-05-01

    Increased incidence of microbial infection in distillate fuels has led to a demand for organisations such as the Institute of Petroleum to propose standards for microbiological quality, based on numbers of viable microbial colony forming units. Variations in quality requirements, and in the spoilage significance of contaminating microbes plus a tendency for temporal and spatial changes in the distribution of microbes, makes such standards difficult to implement. The problem is compounded by a diversity in the procedures employed for sampling and testing for microbial contamination and in the interpretation of the data obtained. The following paper reviews these problems and describes the efforts of The Institute of Petroleum Microbiology Fuels Group to address these issues and in particular to bring about harmonisation of sampling and testing methods. The benefits and drawbacks of available test methods, both laboratory based and on-site, are discussed.

  4. A direct sampling method to an inverse medium scattering problem

    KAUST Repository

    Ito, Kazufumi

    2012-01-10

    In this work we present a novel sampling method for time harmonic inverse medium scattering problems. It provides a simple tool to directly estimate the shape of the unknown scatterers (inhomogeneous media), and it is applicable even when the measured data are only available for one or two incident directions. A mathematical derivation is provided for its validation. Two- and three-dimensional numerical simulations are presented, which show that the method is accurate even with a few sets of scattered field data, computationally efficient, and very robust with respect to noises in the data. © 2012 IOP Publishing Ltd.

  5. Rock sampling. [method for controlling particle size distribution

    Science.gov (United States)

    Blum, P. (Inventor)

    1971-01-01

    A method for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The method involves cutting grooves in the rock surface to provide a grouping of parallel ridges and subsequently machining the ridges to provide a powder specimen. The machining step may comprise milling, drilling, lathe cutting or the like; but a planing step is advantageous. Control of the particle size distribution is effected primarily by changing the height and width of these ridges. This control exceeds that obtainable by conventional grinding.

  6. Characterization of hazardous waste sites: a methods manual. Volume 2. Available sampling methods (second edition)

    International Nuclear Information System (INIS)

    Ford, P.J.; Turina, P.J.; Seely, D.E.

    1984-12-01

    Investigations at hazardous waste sites and sites of chemical spills often require on-site measurements and sampling activities to assess the type and extent of contamination. This document is a compilation of sampling methods and materials suitable to address most needs that arise during routine waste site and hazardous spill investigations. The sampling methods presented in this document are compiled by media, and were selected on the basis of practicality, economics, representativeness, compatability with analytical considerations, and safety, as well as other criteria. In addition to sampling procedures, sample handling and shipping, chain-of-custody procedures, instrument certification, equipment fabrication, and equipment decontamination procedures are described. Sampling methods for soil, sludges, sediments, and bulk materials cover the solids medium. Ten methods are detailed for surface waters, groundwater and containerized liquids; twelve are presented for ambient air, soil gases and vapors, and headspace gases. A brief discussion of ionizing radiation survey instruments is also provided

  7. The experience sampling method: Investigating students' affective experience

    Science.gov (United States)

    Nissen, Jayson M.; Stetzer, MacKenzie R.; Shemwell, Jonathan T.

    2013-01-01

    Improving non-cognitive outcomes such as attitudes, efficacy, and persistence in physics courses is an important goal of physics education. This investigation implemented an in-the-moment surveying technique called the Experience Sampling Method (ESM) [1] to measure students' affective experience in physics. Measurements included: self-efficacy, cognitive efficiency, activation, intrinsic motivation, and affect. Data are presented that show contrasts in students' experiences (e.g., in physics vs. non-physics courses).

  8. Method for evaluation of radiative properties of glass samples

    Energy Technology Data Exchange (ETDEWEB)

    Mohelnikova, Jitka [Faculty of Civil Engineering, Brno University of Technology, Veveri 95, 602 00 Brno (Czech Republic)], E-mail: mohelnikova.j@fce.vutbr.cz

    2008-04-15

    The paper presents a simple calculation method which serves for an evaluation of radiative properties of window glasses. The method is based on a computer simulation model of the energy balance of a thermally insulated box with selected glass samples. A temperature profile of the air inside of the box with a glass sample exposed to affecting radiation was determined for defined boundary conditions. The spectral range of the radiation was considered in the interval between 280 and 2500 nm. This interval is adequate to the spectral range of solar radiation affecting windows in building facades. The air temperature rise within the box was determined in a response to the affecting radiation in the time between the beginning of the radiation exposition and the time of steady-state thermal conditions. The steady state temperature inside of the insulated box serves for the evaluation of the box energy balance and determination of the glass sample radiative properties. These properties are represented by glass characteristics as mean values of transmittance, reflectance and absorptance calculated for a defined spectral range. The data of the computer simulations were compared to experimental measurements on a real model of the insulated box. Results of both the calculations and measurements are in a good compliance. The method is recommended for preliminary evaluation of window glass radiative properties which serve as data for energy evaluation of buildings.

  9. Radiochemistry methods in DOE methods for evaluating environmental and waste management samples

    International Nuclear Information System (INIS)

    Fadeff, S.K.; Goheen, S.C.

    1994-08-01

    Current standard sources of radiochemistry methods are often inappropriate for use in evaluating US Department of Energy environmental and waste management (DOE/EW) samples. Examples of current sources include EPA, ASTM, Standard Methods for the Examination of Water and Wastewater and HASL-300. Applicability of these methods is limited to specific matrices (usually water), radiation levels (usually environmental levels), and analytes (limited number). Radiochemistry methods in DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) attempt to fill the applicability gap that exists between standard methods and those needed for DOE/EM activities. The Radiochemistry chapter in DOE Methods includes an ''analysis and reporting'' guidance section as well as radiochemistry methods. A basis for identifying the DOE/EM radiochemistry needs is discussed. Within this needs framework, the applicability of standard methods and targeted new methods is identified. Sources of new methods (consolidated methods from DOE laboratories and submissions from individuals) and the methods review process will be discussed. The processes involved in generating consolidated methods add editing individually submitted methods will be compared. DOE Methods is a living document and continues to expand by adding various kinds of methods. Radiochemistry methods are highlighted in this paper. DOE Methods is intended to be a resource for methods applicable to DOE/EM problems. Although it is intended to support DOE, the guidance and methods are not necessarily exclusive to DOE. The document is available at no cost through the Laboratory Management Division of DOE, Office of Technology Development

  10. Application of WSP method in analysis of environmental samples

    International Nuclear Information System (INIS)

    Stacho, M.; Slugen, V.; Hinca, R.; Sojak, S.; Krnac, S.

    2014-01-01

    Detection of activity in natural samples is specific especially because of its low level and high background interferences. Reduction of background interferences could be reached using low background chamber. Measurement geometry in shape of Marinelli beaker is commonly used according to low level of activity in natural samples. The Peak Net Area (PNA) method is the world-wide accepted technique for analysis of gamma-ray spectra. It is based on the net area calculation of the full energy peak, therefore, it takes into account only a fraction of measured gamma-ray spectrum. On the other hand, the Whole Spectrum Processing (WSP) approach to the gamma analysis makes possible to use entire information being in the spectrum. This significantly raises efficiency and improves energy resolution of the analysis. A principal step for the WSP application is building up the suitable response operator. Problems are put in an appearance when suitable standard calibration sources are unavailable. It may be occurred in the case of large volume samples and/or in the analysis of high energy range. Combined experimental and mathematical calibration may be a suitable solution. Many different detectors have been used to register the gamma ray and its energy. HPGe detectors produce the highest resolution commonly available today. Therefore they are they the most often used detectors in natural samples activity analysis. Scintillation detectors analysed using PNA method could be also used in simple cases, but for complicated spectra are practically inapplicable. WSP approach improves resolution of scintillation detectors and expands their applicability. WSP method allowed significant improvement of the energetic resolution and separation of "1"3"7Cs 661 keV peak from "2"1"4Bi 609 keV peak. At the other hand the statistical fluctuations in the lower part of the spectrum highlighted by background subtraction causes that this part is still not reliably analyzable. (authors)

  11. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses

    Energy Technology Data Exchange (ETDEWEB)

    Lange, H.J. de [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands); Centre for Ecosystem Studies, Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen (Netherlands)], E-mail: marieke.delange@wur.nl; Griethuysen, C. van; Koelmans, A.A. [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands)

    2008-01-15

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics. - Change in AVS is a good proxy for sediment disturbance and combined with SEM it can be used as a suitable predictor for biotic effects of sediment contamination.

  12. Analytical Method to Estimate the Complex Permittivity of Oil Samples

    Directory of Open Access Journals (Sweden)

    Lijuan Su

    2018-03-01

    Full Text Available In this paper, an analytical method to estimate the complex dielectric constant of liquids is presented. The method is based on the measurement of the transmission coefficient in an embedded microstrip line loaded with a complementary split ring resonator (CSRR, which is etched in the ground plane. From this response, the dielectric constant and loss tangent of the liquid under test (LUT can be extracted, provided that the CSRR is surrounded by such LUT, and the liquid level extends beyond the region where the electromagnetic fields generated by the CSRR are present. For that purpose, a liquid container acting as a pool is added to the structure. The main advantage of this method, which is validated from the measurement of the complex dielectric constant of olive and castor oil, is that reference samples for calibration are not required.

  13. Method for fractional solid-waste sampling and chemical analysis

    DEFF Research Database (Denmark)

    Riber, Christian; Rodushkin, I.; Spliid, Henrik

    2007-01-01

    four subsampling methods and five digestion methods, paying attention to the heterogeneity and the material characteristics of the waste fractions, it was possible to determine 61 substances with low detection limits, reasonable variance, and high accuracy. For most of the substances of environmental...... of variance (20-85% of the overall variation). Only by increasing the sample size significantly can this variance be reduced. The accuracy and short-term reproducibility of the chemical characterization were good, as determined by the analysis of several relevant certified reference materials. Typically, six...... to eight different certified reference materials representing a range of concentrations levels and matrix characteristics were included. Based on the documentation provided, the methods introduced were considered satisfactory for characterization of the chemical composition of waste-material fractions...

  14. Cascade-pond System Health Assessment Based on Macroinvertebrate Indices and Its Relationship with Impervious Cover and Aquatic Buffer Zone in Urbanized Catchments

    Directory of Open Access Journals (Sweden)

    Zulkarnain Faris

    2017-01-01

    Full Text Available A cascade-pond system consists of six ponds located at Universitas Indonesia Campus, Depok. Its catchment area is dominated by high density urban area with moderate to high imperviousness. Some of riparian buffers surrounds six ponds are also occupied by high imperviousness that may lead some ecohydrological problems i.e. water quality degradation, declining freshwater biodiversity and food web changes. The aim of this study is assessing the current state of cascade-pond system health. The assessment of macroinvertebrate indices is based on SingScore that have been developed by Public Utilities Board of Singapore for macroinvertebrate biotic index. Impervious cover data is obtained from high-resolution imageries and processed using ArcGIS 10.5. Qualitative statistics methods, Chi-squared test describes the relationship of macroinvertebrate indices with catchment area imperviousness and aquatic buffer zone. The health assessment based on macroinvertebrates indices shows that the lower ponds are relatively healthier than the upper one. There is also any significant relationship between macroinvertebrate indices with impervious cover based on chi square test and cross tabulation analysis.

  15. Comparison between powder and slices diffraction methods in teeth samples

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Marcos V.; Barroso, Regina C. [Universidade do Estado do Rio de Janeiro (IF/UERJ), RJ (Brazil). Inst. de Fisica. Dept. de Fisica Aplicada; Porto, Isabel M. [Universidade Estadual de Campinas (FOP/UNICAMP), Piracicaba, SP (Brazil). Fac. de Odontologia. Dept. de Morfologia; Gerlach, Raquel F. [Universidade de Sao Paulo (FORP/USP), Rieirao Preto, SP (Brazil). Fac. de Odontologia. Dept. de Morfologia, Estomatologia e Fisiologia; Costa, Fanny N. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LIN/COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2011-07-01

    Propose different methods to obtain crystallographic information about biological materials are important since powder method is a nondestructive method. Slices are an approximation of what would be an in vivo analysis. Effects of samples preparation cause differences in scattering profiles compared with powder method. The main inorganic component of bones and teeth is a calcium phosphate mineral whose structure closely resembles hydroxyapatite (HAp). The hexagonal symmetry, however, seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. Were analyzed ten third molar teeth. Five teeth were separated in enamel, detin and circumpulpal detin powder and five in slices. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. The LNLS synchrotron light source is composed of a 1.37 GeV electron storage ring, delivering approximately 4x10{sup -1}0 photons/s at 8 keV. A double-crystal Si(111) pre-monochromator, upstream of the beamline, was used to select a small energy bandwidth at 11 keV . Scattering signatures were obtained at intervals of 0.04 deg for angles from 24 deg to 52 deg. The human enamel experimental crystallite size obtained in this work were 30(3)nm (112 reflection) and 30(3)nm (300 reflection). These values were obtained from measurements of powdered enamel. When comparing the slice obtained 58(8)nm (112 reflection) and 37(7)nm (300 reflection) enamel diffraction patterns with those generated by the powder specimens, a few differences emerge. This work shows differences between powder and slices methods, separating characteristics of sample of the method's influence. (author)

  16. Comparison between powder and slices diffraction methods in teeth samples

    International Nuclear Information System (INIS)

    Colaco, Marcos V.; Barroso, Regina C.; Porto, Isabel M.; Gerlach, Raquel F.; Costa, Fanny N.

    2011-01-01

    Propose different methods to obtain crystallographic information about biological materials are important since powder method is a nondestructive method. Slices are an approximation of what would be an in vivo analysis. Effects of samples preparation cause differences in scattering profiles compared with powder method. The main inorganic component of bones and teeth is a calcium phosphate mineral whose structure closely resembles hydroxyapatite (HAp). The hexagonal symmetry, however, seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. Were analyzed ten third molar teeth. Five teeth were separated in enamel, detin and circumpulpal detin powder and five in slices. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. The LNLS synchrotron light source is composed of a 1.37 GeV electron storage ring, delivering approximately 4x10 -1 0 photons/s at 8 keV. A double-crystal Si(111) pre-monochromator, upstream of the beamline, was used to select a small energy bandwidth at 11 keV . Scattering signatures were obtained at intervals of 0.04 deg for angles from 24 deg to 52 deg. The human enamel experimental crystallite size obtained in this work were 30(3)nm (112 reflection) and 30(3)nm (300 reflection). These values were obtained from measurements of powdered enamel. When comparing the slice obtained 58(8)nm (112 reflection) and 37(7)nm (300 reflection) enamel diffraction patterns with those generated by the powder specimens, a few differences emerge. This work shows differences between powder and slices methods, separating characteristics of sample of the method's influence. (author)

  17. Radiochemistry methods in DOE Methods for Evaluating Environmental and Waste Management Samples: Addressing new challenges

    International Nuclear Information System (INIS)

    Fadeff, S.K.; Goheen, S.C.; Riley, R.G.

    1994-01-01

    Radiochemistry methods in Department of Energy Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) add to the repertoire of other standard methods in support of U.S. Department of Energy environmental restoration and waste management (DOE/EM) radiochemical characterization activities. Current standard sources of radiochemistry methods are not always applicable for evaluating DOE/EM samples. Examples of current sources include those provided by the US Environmental Protection Agency, the American Society for Testing and Materials, Standard Methods for the Examination of Water and Wastewater, and Environmental Measurements Laboratory Procedures Manual (HASL-300). The applicability of these methods is generally limited to specific matrices (usually water), low-level radioactive samples, and a limited number of analytes. DOE Methods complements these current standard methods by addressing the complexities of EM characterization needs. The process for determining DOE/EM radiochemistry characterization needs is discussed. In this context of DOE/EM needs, the applicability of other sources of standard radiochemistry methods is defined, and gaps in methodology are identified. Current methods in DOE Methods and the EM characterization needs they address are discussed. Sources of new methods and the methods incorporation process are discussed. The means for individuals to participate in (1) identification of DOE/EM needs, (2) the methods incorporation process, and (3) submission of new methods are identified

  18. A direct sampling method for inverse electromagnetic medium scattering

    KAUST Repository

    Ito, Kazufumi

    2013-09-01

    In this paper, we study the inverse electromagnetic medium scattering problem of estimating the support and shape of medium scatterers from scattered electric/magnetic near-field data. We shall develop a novel direct sampling method based on an analysis of electromagnetic scattering and the behavior of the fundamental solution. It is applicable to a few incident fields and needs only to compute inner products of the measured scattered field with the fundamental solutions located at sampling points. Hence, it is strictly direct, computationally very efficient and highly robust to the presence of data noise. Two- and three-dimensional numerical experiments indicate that it can provide reliable support estimates for multiple scatterers in the case of both exact and highly noisy data. © 2013 IOP Publishing Ltd.

  19. Monte Carlo burnup codes acceleration using the correlated sampling method

    International Nuclear Information System (INIS)

    Dieudonne, C.

    2013-01-01

    For several years, Monte Carlo burnup/depletion codes have appeared, which couple Monte Carlo codes to simulate the neutron transport to deterministic methods, which handle the medium depletion due to the neutron flux. Solving Boltzmann and Bateman equations in such a way allows to track fine 3-dimensional effects and to get rid of multi-group hypotheses done by deterministic solvers. The counterpart is the prohibitive calculation time due to the Monte Carlo solver called at each time step. In this document we present an original methodology to avoid the repetitive and time-expensive Monte Carlo simulations, and to replace them by perturbation calculations: indeed the different burnup steps may be seen as perturbations of the isotopic concentration of an initial Monte Carlo simulation. In a first time we will present this method, and provide details on the perturbative technique used, namely the correlated sampling. In a second time we develop a theoretical model to study the features of the correlated sampling method to understand its effects on depletion calculations. In a third time the implementation of this method in the TRIPOLI-4 code will be discussed, as well as the precise calculation scheme used to bring important speed-up of the depletion calculation. We will begin to validate and optimize the perturbed depletion scheme with the calculation of a REP-like fuel cell depletion. Then this technique will be used to calculate the depletion of a REP-like assembly, studied at beginning of its cycle. After having validated the method with a reference calculation we will show that it can speed-up by nearly an order of magnitude standard Monte-Carlo depletion codes. (author) [fr

  20. Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates

    Science.gov (United States)

    2018-01-01

    Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20–500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species. PMID:29337537

  1. A GPU code for analytic continuation through a sampling method

    Directory of Open Access Journals (Sweden)

    Johan Nordström

    2016-01-01

    Full Text Available We here present a code for performing analytic continuation of fermionic Green’s functions and self-energies as well as bosonic susceptibilities on a graphics processing unit (GPU. The code is based on the sampling method introduced by Mishchenko et al. (2000, and is written for the widely used CUDA platform from NVidia. Detailed scaling tests are presented, for two different GPUs, in order to highlight the advantages of this code with respect to standard CPU computations. Finally, as an example of possible applications, we provide the analytic continuation of model Gaussian functions, as well as more realistic test cases from many-body physics.

  2. Methods of scaling threshold color difference using printed samples

    Science.gov (United States)

    Huang, Min; Cui, Guihua; Liu, Haoxue; Luo, M. Ronnier

    2012-01-01

    A series of printed samples on substrate of semi-gloss paper and with the magnitude of threshold color difference were prepared for scaling the visual color difference and to evaluate the performance of different method. The probabilities of perceptibly was used to normalized to Z-score and different color differences were scaled to the Z-score. The visual color difference was got, and checked with the STRESS factor. The results indicated that only the scales have been changed but the relative scales between pairs in the data are preserved.

  3. National comparison on volume sample activity measurement methods

    International Nuclear Information System (INIS)

    Sahagia, M.; Grigorescu, E.L.; Popescu, C.; Razdolescu, C.

    1992-01-01

    A national comparison on volume sample activity measurements methods may be regarded as a step toward accomplishing the traceability of the environmental and food chain activity measurements to national standards. For this purpose, the Radionuclide Metrology Laboratory has distributed 137 Cs and 134 Cs water-equivalent solid standard sources to 24 laboratories having responsibilities in this matter. Every laboratory has to measure the activity of the received source(s) by using its own standards, equipment and methods and report the obtained results to the organizer. The 'measured activities' will be compared with the 'true activities'. A final report will be issued, which plans to evaluate the national level of precision of such measurements and give some suggestions for improvement. (Author)

  4. The impact of sediment removal on the aquatic macroinvertebrate assemblage in a fishpond littoral zone

    Directory of Open Access Journals (Sweden)

    Zdeněk ADÁMEK

    2011-02-01

    Full Text Available Bottom sediment removal, a widely used technique in restoration management of standing water bodies, has a strong influence on communities of aquatic organisms. As most information on the impact of sediment removal on the aquatic environment comes from studies on lakes, the aim of this study was to describe macroinvertebrate assemblage succession in a fishpond (Štěpánek fishpond, Bohemian-Moravian highlands, Czech Republic littoral zone following restoration by sediment removal during the winter of 2003/2004. Semi-quantitative hand net sampling was undertaken one year before (2003 and in each of the following five years (2004–2008 after sediment removal. A significant decrease in both abundance (approx. 90% of individuals and diversity (approx. 30% of taxa of macroinvertebrates was detected immediately after pond restoration. The values gradually increased over subsequent years, reaching comparable abundance and diversity three years after sediment removal. A significant shift was recorded in the taxonomic and functional composition of the macroinvertebrate assemblage after sediment removal. Mayfly larvae were the dominant invertebrates before restoration, while chironomid larvae and oligochaetes dominated after sediment removal. Phytophilous taxa, grazers and scrapers, and swimming or diving invertebrates were common in 2003, whilst open-water taxa preferring mud and other mostly inorganic microhabitats, gatherers/collectors, and burrowing/boring invertebrates were relatively common after sediment removal. In 2008, the assemblage reverted towards the situation before sediment removal, probably connected with a lower water level and accelerated macrophyte bed succession. Principal Component Analysis on the species data confirmed the differences in invertebrate taxonomic structure among sampling years. Succession of the fishpond invertebrate assemblage in the years following sediment removal was mainly influenced by fish farming practice and

  5. Verification of spectrophotometric method for nitrate analysis in water samples

    Science.gov (United States)

    Kurniawati, Puji; Gusrianti, Reny; Dwisiwi, Bledug Bernanti; Purbaningtias, Tri Esti; Wiyantoko, Bayu

    2017-12-01

    The aim of this research was to verify the spectrophotometric method to analyze nitrate in water samples using APHA 2012 Section 4500 NO3-B method. The verification parameters used were: linearity, method detection limit, level of quantitation, level of linearity, accuracy and precision. Linearity was obtained by using 0 to 50 mg/L nitrate standard solution and the correlation coefficient of standard calibration linear regression equation was 0.9981. The method detection limit (MDL) was defined as 0,1294 mg/L and limit of quantitation (LOQ) was 0,4117 mg/L. The result of a level of linearity (LOL) was 50 mg/L and nitrate concentration 10 to 50 mg/L was linear with a level of confidence was 99%. The accuracy was determined through recovery value was 109.1907%. The precision value was observed using % relative standard deviation (%RSD) from repeatability and its result was 1.0886%. The tested performance criteria showed that the methodology was verified under the laboratory conditions.

  6. Methods to maximise recovery of environmental DNA from water samples.

    Directory of Open Access Journals (Sweden)

    Rheyda Hinlo

    Full Text Available The environmental DNA (eDNA method is a detection technique that is rapidly gaining credibility as a sensitive tool useful in the surveillance and monitoring of invasive and threatened species. Because eDNA analysis often deals with small quantities of short and degraded DNA fragments, methods that maximize eDNA recovery are required to increase detectability. In this study, we performed experiments at different stages of the eDNA analysis to show which combinations of methods give the best recovery rate for eDNA. Using Oriental weatherloach (Misgurnus anguillicaudatus as a study species, we show that various combinations of DNA capture, preservation and extraction methods can significantly affect DNA yield. Filtration using cellulose nitrate filter paper preserved in ethanol or stored in a -20°C freezer and extracted with the Qiagen DNeasy kit outperformed other combinations in terms of cost and efficiency of DNA recovery. Our results support the recommendation to filter water samples within 24hours but if this is not possible, our results suggest that refrigeration may be a better option than freezing for short-term storage (i.e., 3-5 days. This information is useful in designing eDNA detection of low-density invasive or threatened species, where small variations in DNA recovery can signify the difference between detection success or failure.

  7. BMAA extraction of cyanobacteria samples: which method to choose?

    Science.gov (United States)

    Lage, Sandra; Burian, Alfred; Rasmussen, Ulla; Costa, Pedro Reis; Annadotter, Heléne; Godhe, Anna; Rydberg, Sara

    2016-01-01

    β-N-Methylamino-L-alanine (BMAA), a neurotoxin reportedly produced by cyanobacteria, diatoms and dinoflagellates, is proposed to be linked to the development of neurological diseases. BMAA has been found in aquatic and terrestrial ecosystems worldwide, both in its phytoplankton producers and in several invertebrate and vertebrate organisms that bioaccumulate it. LC-MS/MS is the most frequently used analytical technique in BMAA research due to its high selectivity, though consensus is lacking as to the best extraction method to apply. This study accordingly surveys the efficiency of three extraction methods regularly used in BMAA research to extract BMAA from cyanobacteria samples. The results obtained provide insights into possible reasons for the BMAA concentration discrepancies in previous publications. In addition and according to the method validation guidelines for analysing cyanotoxins, the TCA protein precipitation method, followed by AQC derivatization and LC-MS/MS analysis, is now validated for extracting protein-bound (after protein hydrolysis) and free BMAA from cyanobacteria matrix. BMAA biological variability was also tested through the extraction of diatom and cyanobacteria species, revealing a high variance in BMAA levels (0.0080-2.5797 μg g(-1) DW).

  8. The role of macroinvertebrates for conservation of freshwater systems.

    Science.gov (United States)

    Nieto, Carolina; Ovando, Ximena M C; Loyola, Rafael; Izquierdo, Andrea; Romero, Fátima; Molineri, Carlos; Rodríguez, José; Rueda Martín, Paola; Fernández, Hugo; Manzo, Verónica; Miranda, María José

    2017-07-01

    Freshwater ecosystems are the most threatened ecosystems worldwide. Argentinian-protected areas have been established mainly to protect vertebrates and plants in terrestrial ecosystems. In order to create a comprehensive biodiverse conservation plan, it is crucial to integrate both aquatic and terrestrial systems and to include macroinvertebrates. Here, we address this topic by proposing priority areas of conservation including invertebrates, aquatic ecosystems, and their connectivity and land uses. Northwest of Argentina. We modeled the ecological niches of different taxa of macroinvertebrates such as Coleoptera, Ephemeroptera, Hemiptera, Megaloptera, Lepidoptera, Odonata, Plecoptera, Trichoptera, Acari, and Mollusca. Based on these models, we analyzed the contribution of currently established protected areas in the conservation of the aquatic biodiversity and we propose a spatial prioritization taking into account possible conflict regarding different land uses. Our analysis units were the real watersheds, to which were added longitudinal connectivity up and down the rivers. A total of 132 species were modeled in the priority area analyses. The analysis 1 showed that only an insignificant percentage of the macroinvertebrates distribution is within the protected areas in the North West of Argentina. The analyses 2 and 3 recovered similar values of protection for the macroinvertebrate species. The upper part of Bermejo, Salí-Dulce, San Francisco, and the Upper part of Juramento basins were identified as priority areas of conservation. The aquatic ecosystems need special protection and 10% or even as much as 17% of land conservation is insufficient for species of macroinvertebrates. In turn the protected areas need to combine the aquatic and terrestrial systems and need to include macroinvertebrates as a key group to sustain the biodiversity. In many cases, the land uses are in conflict with the conservation of biodiversity; however, it is possible to apply the

  9. Are the streams of the Sinos River basin of good water quality? Aquatic macroinvertebrates may answer the question

    Directory of Open Access Journals (Sweden)

    L. Bieger

    Full Text Available Macroinvertebrate communities are one of the most used groups in assessments of water quality, since they respond directly to the level of contamination of aquatic ecosystems. The main objective of this study was the assessment of the water quality of the Sinos River basin (Rio Grande do Sul state, Brazil through biotic indices based on the macroinvertebrate community ("Family Biotic Index - FBI", and "Biological Monitoring Working Party Score System - BMWP". Three lower order streams (2nd order were selected in each one of three main regions of the basin. In each stream, the samplings were performed in three reaches (upper, middle, and lower, totalling 27 reaches. Two samplings were carried in each reach over one year (winter and summer. A total of 6,847 macroinvertebrates distributed among 54 families were sampled. The streams from the upper region were of better water quality than the lower region. The water quality did not change between the upper, middle and lower reaches of the streams. However, the upper reaches of the streams were of better water quality in all the regions of the basin. The water quality of the streams did not vary between the summer and the winter. This result demonstrated that water quality may be analysed in both studied seasons (summer and winter using biotic indices. The analysis of the results allows us to conclude that the biotic indices used reflected the changes related to the water quality along the longitudinal gradient of the basin. Thus, aquatic macroinvertebrates were important bioindicators of the water and environmental quality of the streams of the Sinos River basin.

  10. Clustering Methods with Qualitative Data: a Mixed-Methods Approach for Prevention Research with Small Samples.

    Science.gov (United States)

    Henry, David; Dymnicki, Allison B; Mohatt, Nathaniel; Allen, James; Kelly, James G

    2015-10-01

    Qualitative methods potentially add depth to prevention research but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed-methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed-methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-means clustering, and latent class analysis produced similar levels of accuracy with binary data and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a "real-world" example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities.

  11. Clustering Methods with Qualitative Data: A Mixed Methods Approach for Prevention Research with Small Samples

    Science.gov (United States)

    Henry, David; Dymnicki, Allison B.; Mohatt, Nathaniel; Allen, James; Kelly, James G.

    2016-01-01

    Qualitative methods potentially add depth to prevention research, but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data, but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-Means clustering, and latent class analysis produced similar levels of accuracy with binary data, and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a “real-world” example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities. PMID:25946969

  12. Recovery of lotic macroinvertebrate communities from disturbance

    Science.gov (United States)

    Wallace, J. Bruce

    1990-09-01

    Ecosystem disturbances produce changes in macrobenthic community structure (abundances, biomass, and production) that persist for a few weeks to many decades. Examples of disturbances with extremely long-term effects on benthic communities include contamination by persistent toxic agents, physical changes in habitats, and altered energy inputs. Stream size, retention, and local geomorphology may ameliorate the influence of disturbances on invertebrates. Disturbances can alter food webs and may select for favorable genotypes (e.g., insecticidal resistance). Introductions of pesticides into lotic ecosystems, which do not result in major physical changes within habitats, illustrate several factors that influence invertebrate recovery time from disturbance. These include: (1) magnitude of original contamination, toxicity, and extent of continued use; (2) spatial scale of the disturbance; (3) persistence of the pesticide; (4) timing of the contamination in relation to the life history stages of the organisms; (5) vagility of populations influenced by pesticides; and (6) position within the drainage network. The ability of macroinvertebrates to recolonize denuded stream habitats may vary greatly depending on regional life histories, dispersal abilities, and position within the stream network (e.g., headwaters vs larger rivers). Although downstream drift is the most frequently cited mechanism of invertebrate recolonization following disturbance in middle- and larger-order streams, evidence is presented that shows aerial recolonization to be potentially important in headwater streams. There is an apparent stochastic element operating for aerial recolonization, depending on the timing of disturbance and flight periods of various taxa. Available evidence indicates that recolonization of invertebrate taxa without an aerial adult stage requires longer periods of time than for those that possess winged, terrestrial adult stages (i.e., most insects). Innovative, manipulative

  13. An adaptive sampling and windowing interrogation method in PIV

    Science.gov (United States)

    Theunissen, R.; Scarano, F.; Riethmuller, M. L.

    2007-01-01

    This study proposes a cross-correlation based PIV image interrogation algorithm that adapts the number of interrogation windows and their size to the image properties and to the flow conditions. The proposed methodology releases the constraint of uniform sampling rate (Cartesian mesh) and spatial resolution (uniform window size) commonly adopted in PIV interrogation. Especially in non-optimal experimental conditions where the flow seeding is inhomogeneous, this leads either to loss of robustness (too few particles per window) or measurement precision (too large or coarsely spaced interrogation windows). Two criteria are investigated, namely adaptation to the local signal content in the image and adaptation to local flow conditions. The implementation of the adaptive criteria within a recursive interrogation method is described. The location and size of the interrogation windows are locally adapted to the image signal (i.e., seeding density). Also the local window spacing (commonly set by the overlap factor) is put in relation with the spatial variation of the velocity field. The viability of the method is illustrated over two experimental cases where the limitation of a uniform interrogation approach appears clearly: a shock-wave-boundary layer interaction and an aircraft vortex wake. The examples show that the spatial sampling rate can be adapted to the actual flow features and that the interrogation window size can be arranged so as to follow the spatial distribution of seeding particle images and flow velocity fluctuations. In comparison with the uniform interrogation technique, the spatial resolution is locally enhanced while in poorly seeded regions the level of robustness of the analysis (signal-to-noise ratio) is kept almost constant.

  14. Stream macroinvertebrate communities across a gradient of natural gas development in the Fayetteville Shale.

    Science.gov (United States)

    Johnson, Erica; Austin, Bradley J; Inlander, Ethan; Gallipeau, Cory; Evans-White, Michelle A; Entrekin, Sally

    2015-10-15

    Oil and gas extraction in shale plays expanded rapidly in the U.S. and is projected to expand globally in the coming decades. Arkansas has doubled the number of gas wells in the state since 2005 mostly by extracting gas from the Fayetteville Shale with activity concentrated in mixed pasture-deciduous forests. Concentrated well pads in close proximity to streams could have adverse effects on stream water quality and biota if sedimentation associated with developing infrastructure or contamination from fracturing fluid and waste occurs. Cumulative effects of gas activity and local habitat conditions on macroinvertebrate communities were investigated across a gradient of gas well activity (0.2-3.6 wells per km(2)) in ten stream catchments in spring 2010 and 2011. In 2010, macroinvertebrate density was positively related to well pad inverse flowpath distance from streams (r=0.84, pgas activity close to streams. However, stream water turbidity (r=0.69, p=0.02) and chlorophyll a (r=0.89, pgas well activities. In 2011, a year with record spring flooding, a different pattern emerged where mayfly density (p=0.74, p=0.01) and mayfly, stonefly, and caddisfly richness (r=0.78, p=0.008) increased in streams with greater well density and less silt cover. Hydrology and well pad placement in a catchment may interact to result in different relationships between biota and catchment activity between the two sample years. Our data show evidence of different macroinvertebrate communities expressed in catchments with different levels of gas activity that reinforce the need for more quantitative analyses of cumulative freshwater-effects from oil and gas development. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Long-Term Benthic Macroinvertebrate Community Monitoring to Assess Pollution Abatement Effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Smith, John G [ORNL; Brandt, Craig C [ORNL; Christensen, Sigurd W [ORNL

    2011-01-01

    The benthic macroinvertebrate community of East Fork Poplar Creek (EFPC) in East Tennessee was monitored for 18 years to evaluate the effectiveness of a water pollution control program implemented at a major United States (U.S.) Department of Energy facility. Several actions were implemented to reduce and control releases of pollutants into the headwaters of the stream. Four of the most significant actions were implemented during different time periods, which allowed assessment of each action. Macroinvertebrate samples were collected annually in April from three locations in EFPC (EFK24, EFK23, and EFK14) and two nearby reference streams from 1986 through 2003. Significant improvements occurred in the macroinvertebrate community at the headwater sites (EFK24 and EFK23) after implementation of each action, while changes detected 9 km further downstream (EFK14) could not be clearly attributed to any of the actions. Because the stream was impacted at its origin, invertebrate recolonization was primarily limited to aerial immigration, thus, recovery has been slow. As recovery progressed, abundances of small pollution-tolerant taxa (e.g., Orthocladiinae chironomids) decreased and longer lived taxa colonized (e.g., hydropsychid caddisflies, riffle beetles, Baetis). While assessments lasting three to four years may be long enough to detect a response to new pollution controls at highly impacted locations, more time may be needed to understand the full effects. Studies on the effectiveness of pollution controls can be improved if impacted and reference sites are selected to maximize spatial and temporal trending, and if a multidisciplinary approach is used to broadly assess environmental responses (e.g., water quality trends, invertebrate and fish community assessments, toxicity testing, etc.).

  16. Spatial and temporal effects of olive mill wastewaters to stream macroinvertebrates and aquatic ecosystems status.

    Science.gov (United States)

    Karaouzas, Ioannis; Skoulikidis, Nikolaos T; Giannakou, Urania; Albanis, Triantafyllos A

    2011-12-01

    Olive mill wastewater (OMW) is one of the major and most challenging organic pollutants in olive oil production countries. However, the knowledge about the in-situ effects of olive mill wastewaters to lotic ecosystems and their benthic organisms is very limited. To resolve this, eight sampling sites were selected upstream and downstream the outflow of several olive mills to assess the spatial and temporal effects of OMW to stream macroinvertebrates and to ecological status of stream ecosystems. Biotic (macroinvertebrates) and abiotic (physicochemical, hydromorphological) data were monitored for two years thus following the biennial cycle of olive growth and production and hydrological variation (drought-wet years). The results of this study revealed the spatial and temporal structural deterioration of the aquatic community due to OMW pollution with consequent reduction of the river capacity for reducing the effects of polluting substances through internal mechanisms of self-purification. OMW, even highly diluted, had dramatic impacts on the aquatic fauna and to the ecological status of the receiving stream ecosystems. The organic load of the wastewater expressed as BOD(5), COD and TSS, substrate contamination (sewage bacteria) and distance from the mill outlet, were the most important factors affecting macroinvertebrate assemblages while the typology (i.e. slope, altitude) and hydrology of the stream site (i.e. mountainous-lowland) and the intensity and volume of the wastewater were the most important determinants of self-purification processes. As OMW are usually being discharged in small size streams that are not considered in the Water Framework Directive 2000/60/EC, there is a need for including such systems into monitoring and assessment schemes as they may significantly contribute to the pollution load of the river basin. Furthermore, guidelines to manage these wastes through technologies that minimise their environmental impact and lead to a sustainable use

  17. Martian Radiative Transfer Modeling Using the Optimal Spectral Sampling Method

    Science.gov (United States)

    Eluszkiewicz, J.; Cady-Pereira, K.; Uymin, G.; Moncet, J.-L.

    2005-01-01

    The large volume of existing and planned infrared observations of Mars have prompted the development of a new martian radiative transfer model that could be used in the retrievals of atmospheric and surface properties. The model is based on the Optimal Spectral Sampling (OSS) method [1]. The method is a fast and accurate monochromatic technique applicable to a wide range of remote sensing platforms (from microwave to UV) and was originally developed for the real-time processing of infrared and microwave data acquired by instruments aboard the satellites forming part of the next-generation global weather satellite system NPOESS (National Polarorbiting Operational Satellite System) [2]. As part of our on-going research related to the radiative properties of the martian polar caps, we have begun the development of a martian OSS model with the goal of using it to perform self-consistent atmospheric corrections necessary to retrieve caps emissivity from the Thermal Emission Spectrometer (TES) spectra. While the caps will provide the initial focus area for applying the new model, it is hoped that the model will be of interest to the wider Mars remote sensing community.

  18. Method for estimating modulation transfer function from sample images.

    Science.gov (United States)

    Saiga, Rino; Takeuchi, Akihisa; Uesugi, Kentaro; Terada, Yasuko; Suzuki, Yoshio; Mizutani, Ryuta

    2018-02-01

    The modulation transfer function (MTF) represents the frequency domain response of imaging modalities. Here, we report a method for estimating the MTF from sample images. Test images were generated from a number of images, including those taken with an electron microscope and with an observation satellite. These original images were convolved with point spread functions (PSFs) including those of circular apertures. The resultant test images were subjected to a Fourier transformation. The logarithm of the squared norm of the Fourier transform was plotted against the squared distance from the origin. Linear correlations were observed in the logarithmic plots, indicating that the PSF of the test images can be approximated with a Gaussian. The MTF was then calculated from the Gaussian-approximated PSF. The obtained MTF closely coincided with the MTF predicted from the original PSF. The MTF of an x-ray microtomographic section of a fly brain was also estimated with this method. The obtained MTF showed good agreement with the MTF determined from an edge profile of an aluminum test object. We suggest that this approach is an alternative way of estimating the MTF, independently of the image type. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Aquatic macroinvertebrates and water quality of Sandia Canyon, Los Alamos National Laboratory, December 1992--October 1993. Status report

    International Nuclear Information System (INIS)

    Cross, S.

    1994-09-01

    In the summer of 1990, an accidental spill from the TA-3 Power Plant Environment Tank released more than 3,785 liters of sulfuric acid into upper Sandia Canyon. The Biological Resource Evaluation Team (BRET) of EM-8 at Los Alamos National Laboratory (LANL) has collected aquatic samples from the stream within Sandia Canyon since then. These field studies gather water quality measurements and collect macroinvertebrates from permanent sampling sites. An earlier report by Bennett (1994) discusses previous BRET aquatic studies in Sandia Canyon. This report updates and expands Bennett's initial findings. During 1993, BRET collected water quality data and aquatic macroinvertebrates at five permanent stations within the canyon. The substrates of the upper three stations are largely sands and silts while the substrates of the two lower stations are largely rock and cobbles. The two upstream stations are located near outfalls that discharge industrial and sanitary waste effluent. The third station is within a natural cattail marsh, approximately 0.4 km (0.25 mi) downstream from Stations SC1 and SC2. Water quality parameters are slightly different at these first three stations from those expected of natural streams, suggesting slightly degraded water quality. Correspondingly, the macroinvertebrate communities at these stations are characterized by low diversities and poorly-developed community structures. The two downstream stations appear to be in a zone of recovery, where water quality parameters more closely resemble those found in natural streams of the area. Macroinvertebrate diversity increases and community structure becomes more complex at the two lower stations, which are further indications of improved water quality downstream

  20. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods.

    Science.gov (United States)

    Coes, Alissa L; Paretti, Nicholas V; Foreman, William T; Iverson, Jana L; Alvarez, David A

    2014-03-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19-23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method. Published by Elsevier B.V.

  1. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods

    Science.gov (United States)

    Coes, Alissa L.; Paretti, Nicholas V.; Foreman, William T.; Iverson, Jana L.; Alvarez, David A.

    2014-01-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19–23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

  2. Failure Probability Calculation Method Using Kriging Metamodel-based Importance Sampling Method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seunggyu [Korea Aerospace Research Institue, Daejeon (Korea, Republic of); Kim, Jae Hoon [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)

    2017-05-15

    The kernel density was determined based on sampling points obtained in a Markov chain simulation and was assumed to be an important sampling function. A Kriging metamodel was constructed in more detail in the vicinity of a limit state. The failure probability was calculated based on importance sampling, which was performed for the Kriging metamodel. A pre-existing method was modified to obtain more sampling points for a kernel density in the vicinity of a limit state. A stable numerical method was proposed to find a parameter of the kernel density. To assess the completeness of the Kriging metamodel, the possibility of changes in the calculated failure probability due to the uncertainty of the Kriging metamodel was calculated.

  3. Impact of heated waters on water quality and macroinvertebrate community in the Narew River (Poland

    Directory of Open Access Journals (Sweden)

    Krolak Elzbieta

    2017-07-01

    Full Text Available The effect of heated waters from coal-burning power stations on the water parameters and the occurrence of macroinvertebrates depends on the individual characteristics of the river to which the heated waters are discharged. The objective of the study was to assess the impact of heated water from the Ostrołęka Power Station on selected water properties and the macroinvertebrate community in the Narew River. Samples were collected in years: 2013-2016 along two river stretches: upstream and downstream of the canal. The water temperature was higher and the oxygen concentrations were lower at the downstream sites compared to the upstream sites of the canal. The values of conductivity, concentrations of nitrates, phosphates, chlorides and calcium were similar at the sampling sites. A total of 33 families of macrozoobenthos were found. The numbers of families were positively correlated with the temperature and conductivity and negatively correlated with oxygen. The heated waters were found to have no effect on the Shannon-Wiener diversity index. The inflow of heated waters increased the percentage of Gammaridae, represented by species Dikerogammarus haemobaphes (Eichwald, 1841 and decreased the percentage of Chironomidae. The presence of the thermophilous bivalve Sinanodonta woodiana (Lea, 1934 was noted downstream of the canal.

  4. Benthic macroinvertebrate assemblages and sediment toxicity testing in the Ely Creek watershed restoration project

    International Nuclear Information System (INIS)

    Soucek, D.J.; Currie, R.J.; Cherry, D.S.; Latimer, H.A.

    1998-01-01

    The Ely Creek watershed in Lee County, Virginia, contains an abundance of abandoned mined land (AML) seeps that contaminate the majority of the creek and its confluence into Big Stone Creek. Contaminated sediments had high concentrations of iron (∼10,000 mg/kg), aluminum (∼1,500 mg/kg), magnesium (∼400 mg/kg) and manganese (∼150 mg/kg). Copper and zinc generally ranged from 3 to 20 mg/kg. Benthic macroinvertebrates surveys at six of 20 sites sampled in the watershed yielded no macroinvertebrates, while eight others had total abundances of 1 to 9 organisms. Four reference sites contained ≥100 organisms and at least 14 different taxa. Laboratory, 10-day survival/impairment sediments tests with Daphnia magna did not support the field data. Mortality of 92 to 100% for D. magna occurred in samples collected from six cities. Daphnid reproduction was more sensitive than laboratory test organism survivorship; however, neither daphnid survivorship nor reproduction were good predictors of taxa richness. Laboratory test concerns included the use of a reference diluent water rather than site specific diluent water

  5. Effects of cutting disturbance in Schoenoplectus californicus (C.A. Mey. Soják on the benthic macroinvertebrates - doi: 10.4025/actascibiolsci.v33i1.6383 Effects of cutting disturbance in Schoenoplectus californicus (C.A. Mey. Soják on the benthic macroinvertebrates - doi: 10.4025/actascibiolsci.v33i1.6383

    Directory of Open Access Journals (Sweden)

    Norma Luiza Würdig

    2011-02-01

    Full Text Available Lagoons are considered protected areas because these systems play a key ecological role. However, the extraction of macrophyte Schoenoplectus californicus is held for manufacture of handcrafts, being an alternative income for riverbank communities. This study evaluated the impact of S. californicus experimental cutting on benthic macroinvertebrates trough a field experiment. Macroinvertebrates were sampled at 1, 12, 26 and 60 days after the macrophyte cutting in demarked plots (1 m², as well at control plots. The families number was not statistically different (ANOVA, p > 0.05, but the total density of invertebrates, and the density of Ceratopogonidae were significant (ANOVA, p S. californicus, in this area, as the intensity of the cut held, did not affect considerably the aquatic macroinvertebrates. The results suggest that the small-scale extractivism in these regions carries little effect because the fauna of adjacent areas probably can quickly colonize the disturbed areas.Lagoons are considered protected areas because these systems play a key ecological role. However, the extraction of macrophyte Schoenoplectus californicus is held for manufacture of handcrafts, being an alternative income for riverbank communities. This study evaluated the impact of S. californicus experimental cutting on benthic macroinvertebrates trough a field experiment. Macroinvertebrates were sampled at 1, 12, 26 and 60 days after the macrophyte cutting in demarked plots (1 m², as well at control plots. The families number was not statistically different (ANOVA, p > 0.05, but the total density of invertebrates, and the density of Ceratopogonidae were significant (ANOVA, p S. californicus, in this area, as the intensity of the cut held, did not affect considerably the aquatic macroinvertebrates. The results suggest that the small-scale extractivism in these regions carries little effect because the fauna of adjacent areas probably can quickly colonize the disturbed

  6. Mesohabitat mosaic in lowland braided rivers: Short-term variability of macroinvertebrate metacommunities

    Directory of Open Access Journals (Sweden)

    Gemma Burgazzi

    2017-04-01

    Full Text Available Braided rivers are among the most variable and dynamic riverine systems. Changes in these environments are sudden and frequent, driven by the high hydrological variability. They host high levels of local heterogeneity, with many different habitats in close proximity establishing a mosaic of patches. This provides the conditions for high levels of biodiversity, with strong community variability in particular among the different habitats at the stream-reach level. Nevertheless, these systems are still poorly studied and their complexity is often not taken into account in biomonitoring protocols. We applied mixed effects modelling, spatial ordination techniques and beta-diversity partitioning (into nestedness and turnover components with the aim of improving the knowledge of braided rivers, investigating: i the organization of macroinvertebrate communities among the different habitats of a river reach, and ii the temporal variability of this organization (both among seasons and during summer. We predicted a differentiation of macroinvertebrate communities between distinct habitats within rivers, with this differentiation increasing during the low-flow period. We carried out our study in four braided rivers and streams of the Po River basin (Northern Italy sampling three different kinds of mesohabitats (main channel, secondary channel and pool in eight stations during seven campaigns from June 2015 to April 2016. We found a high variability of taxa richness, abundance and community structure among mesohabitats, with marginal ones accounting for the greater part of macroinvertebrate diversity. Secondary channels resulted as being the habitat hosting greater taxa diversity, with 10 exclusive taxa. Surprisingly the mesohabitat communities differed greatly during the seasonal phase, whereas their dissimilarity decreased during summer. This could be explained considering the summer flow reduction as a homogenizing force, leading to a general loss of the

  7. Soil macroinvertebrates along a successional gradient in central Florida

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; Ali, A.

    2004-01-01

    Roč. 87, č. 3 (2004), s. 386-390 ISSN 0015-4040 Institutional research plan: CEZ:AV0Z6066911 Keywords : soil macroinvertebrates * successional gradient * central Florida Subject RIV: EH - Ecology, Behaviour Impact factor: 0.786, year: 2004

  8. Benthic macroinvertebrate community of a fourth order stream in ...

    African Journals Online (AJOL)

    cinthia

    Full Length Research Paper. Benthic macroinvertebrate community of a fourth order stream in Kashmir Himalaya, India. Shazia Habib1* and A.R. Yousuf2. 1Department of Environmental Science, University of Kashmir, Srinagar, India. 2National Green Tribunal, Government of India, India. Received 31 December, 2013; ...

  9. Patterning and predicting aquatic macroinvertebrate diversities using artificial neural network

    NARCIS (Netherlands)

    Park, Y.S.; Verdonschot, P.F.M.; Chon, T.S.; Lek, S.

    2003-01-01

    A counterpropagation neural network (CPN) was applied to predict species richness (SR) and Shannon diversity index (SH) of benthic macroinvertebrate communities using 34 environmental variables. The data were collected at 664 sites at 23 different water types such as springs, streams, rivers,

  10. The effect of plant density on epiphytic macroinvertebrates ...

    African Journals Online (AJOL)

    The effect of variations in the density of a submerged macrophyte,Lagarosiphon ilicifolius, on epiphytic macroinvertebrate community structure in the shallow waters of a sheltered bay of Lake Kariba were investigated. The body size class distributions of a mayfly, Cloeon (Ephemeroptera: Baetidae), and the damselfly family, ...

  11. Physico-chemical conditions and macroinvertebrate fauna in the ...

    African Journals Online (AJOL)

    This paper examines the distribution of benthic macroinvertebrates in relation to physico-chemical conditions along 1 035km of the River Nile from Aswan High Dam to Al Kanater Barrage, Cairo. Total Dissolved Salts and several individual chemical variables showed positive linear regression with distance from Aswan.

  12. Effects of oil pollution on aquatic macroinvertebrate assemblages in ...

    African Journals Online (AJOL)

    Macroinvertebrate assemblages from uncontaminated and contaminated sites in the Gamba Complex (Gabon) were compared, the latter sites having been subjected to ongoing oil spills since the 1970s. Vegetation communities surrounding the sites included savannah, shrub–scrub, palm forest, gallery forest and thick ...

  13. Ecology of benthic macroinvertebrates in the depositional biotope of ...

    African Journals Online (AJOL)

    The ecology of benthic macroinvertebrates was studied in the depositional biotope of a river in southern Nigeria in two contrasting tidally influenced fresh and brackish water stations. Forty five taxa in nineteen families representing seven major groups of benthos were recorded. The molluscan families, dominated by ...

  14. Impacts of trout on aquatic macroinvertebrates in three Drakensberg ...

    African Journals Online (AJOL)

    Further studies are recommended in order to provide additional information on seasonal variation in these patterns, as well as on density-dependent effects of trout on aquatic macroinvertebrate communities. Keywords: management, Oncorhynchus mykiss, Salmo trutta, Ukhahlamba-Drakensberg Park, waterfalls

  15. Sequential sampling: a novel method in farm animal welfare assessment.

    Science.gov (United States)

    Heath, C A E; Main, D C J; Mullan, S; Haskell, M J; Browne, W J

    2016-02-01

    Lameness in dairy cows is an important welfare issue. As part of a welfare assessment, herd level lameness prevalence can be estimated from scoring a sample of animals, where higher levels of accuracy are associated with larger sample sizes. As the financial cost is related to the number of cows sampled, smaller samples are preferred. Sequential sampling schemes have been used for informing decision making in clinical trials. Sequential sampling involves taking samples in stages, where sampling can stop early depending on the estimated lameness prevalence. When welfare assessment is used for a pass/fail decision, a similar approach could be applied to reduce the overall sample size. The sampling schemes proposed here apply the principles of sequential sampling within a diagnostic testing framework. This study develops three sequential sampling schemes of increasing complexity to classify 80 fully assessed UK dairy farms, each with known lameness prevalence. Using the Welfare Quality herd-size-based sampling scheme, the first 'basic' scheme involves two sampling events. At the first sampling event half the Welfare Quality sample size is drawn, and then depending on the outcome, sampling either stops or is continued and the same number of animals is sampled again. In the second 'cautious' scheme, an adaptation is made to ensure that correctly classifying a farm as 'bad' is done with greater certainty. The third scheme is the only scheme to go beyond lameness as a binary measure and investigates the potential for increasing accuracy by incorporating the number of severely lame cows into the decision. The three schemes are evaluated with respect to accuracy and average sample size by running 100 000 simulations for each scheme, and a comparison is made with the fixed size Welfare Quality herd-size-based sampling scheme. All three schemes performed almost as well as the fixed size scheme but with much smaller average sample sizes. For the third scheme, an overall

  16. Some aspects of the distribution and dynamics of the benthic macroinvertebrate groups from Nimăieşti valley river

    Directory of Open Access Journals (Sweden)

    CUPŞA Diana

    2005-09-01

    Full Text Available In the Nimăieşti Valley river we found in a number of four sample sites a community of benthic macroinvertebrates represented by Oligochaeta, Ephemeroptera larva, Trichoptera larva, Chironomida larva and Hidracarina species. The communities structure vary depending on season and the sampling site acording to the water quality and trophic condition of the substrate. The greatest diversity was recorded during the summer months (may-august and comparing the sample sites, we found that the first three sampling sites are very similar from the point of view of the macroinvertebrate community, but the fourth sampling site the community is different because the river pases through the town of Beiuş and as a consequence the water quality is lower that at the other three sample sites.

  17. Sediment Burial Intolerance of Marine Macroinvertebrates.

    Directory of Open Access Journals (Sweden)

    Vicki J Hendrick

    Full Text Available The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura, the queen scallop (Aequipecten opercularis and the sea squirt (Ciona intestinalis were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris and the anemone (Sagartiogeton laceratus, showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa. With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally

  18. The effect of biotope-specific sampling for aquatic ...

    African Journals Online (AJOL)

    The effect of biotope-specific sampling for aquatic macroinvertebrates on ... riffle), depth, and quality (deposition of silt on stones), were important at habitat scale. ... Geological type, which affects overall water chemistry, was important in the ...

  19. Spatial variation of macroinvertebrate community structure and associated environmental conditions in a subtropical river system of southeastern China

    Directory of Open Access Journals (Sweden)

    Fu L.

    2015-01-01

    Full Text Available Knowledge of macroinvertebrate distributions and associated environmental drivers in subtropical Asian rivers is relatively scarce. To fill this knowledge gap, we examined the spatial variation of macroinvertebrate community structure and associated environmental conditions in a subtropical river system, the Dongjiang River Basin, in southeastern China. A total of 70 families and 9 classes of macroinvertebrates were identified from 74 sites sampled in January 2013. Our study has the following findings: (1 a distinct spatial differentiation of macroinvertebrate communities was present in the Dongjiang River Basin indicated by non-metric multidimensional scaling (NMDS, which corresponded to the northern region (NR, middle region (MR, and southern region (SR gradient; (2 ANOVAs showed that diversity indices (total taxa, Margalef index and the Shannon diversity index, biotic indices (richness of EPT, percentage of EPT, and family biotic index and most of the studied environmental conditions (elevation, slope, steam order, water temperature, electrical conductivity, dissolved oxygen, pH, substrates, ammoniacal nitrogen, total phosphorus, percentage of urban land, percentage of rural land, and percentage of forest land differed significantly among the three regions and a degradation gradient was observed in the NR–MR–SR direction; (3 Canonical correspondence analysis (CCA revealed that NR sites were characterized by steep slope and coarse substrate, MR sites were characterized by high water temperatures and shallow slopes, and SR sites were primarily characterized by high total phosphorus and ammoniacal nitrogen concentrations; and (4 the Indicator Species Analysis, in conjunction with CCA analysis indicated that the most representative indicator taxon is Tipulidae for NR, Semisulcospira sp. for MR, and Branchiura sp. for SR.

  20. Disturbance caused by freshwater releases of different magnitude on the aquatic macroinvertebrate communities of two coastal lagoons

    Science.gov (United States)

    Cañedo-Argüelles, Miguel; Rieradevall, Maria

    2010-06-01

    The response of the aquatic macroinvertebrate communities to freshwater releases of different magnitude and persistence was investigated in two Mediterranean coastal lagoons (Ca l'Arana and Ricarda). The study was carried out during 14 months (June 2004-July 2005) in which different environmental variables and the macroinvertebrate communities associated with two different habitats, the Phragmites australis belt and the deep area of the lagoons, were sampled monthly. Additionally, potential colonizing sources were identified through the analysis of Chironomidae pupal exuviae. The initial response of the communities to the freshwater releases was similar, being characterized by a peak of opportunistic taxa (mainly Naididae), but the late response was different for each lagoon. In the Ca l'Arana, the magnitude of the freshwater release was higher (salinity dropped below five, which is the limit commonly established for most freshwater species) and its persistence was also higher, allowing the colonization of the lagoon by new insect taxa, which replaced the brackish water species. In the Ricarda, the salinity never dropped beyond five and pre-disturbance conditions were rapidly re-established. This, together with the acclimatizing mechanisms showed by the species Chironomus riparius and Hediste diversicolor, permitted the recovery of the pre-disturbance macroinvertebrate community.

  1. Macroinvertebrate Richness Importance in Coastal Tropical Streams of Esmeraldas (Ecuador and Its Use and Implications in Environmental Management Procedures

    Directory of Open Access Journals (Sweden)

    Carlos Martínez-Sanz

    2014-01-01

    Full Text Available This study was aimed at determining the performance of some indices and community attributes frequently used to assess river quality and test the role of macroinvertebrate taxa richness as element of bioindication in several coastal tropical streams of western Esmeraldas (Ecuador. In addition, a macroinvertebrate taxon list of this region was provided for the first time. Thirteen sampled points distributed across nine streams were selected for this study and nineteen parameters and attributes of bioindication were tested. The differences between nonimpact and impact places were evaluated mainly using one-way analysis of variance. Jackknife 2 and Clench were used to estimate the regional richness and the quality of the inventory, respectively. Seventy taxa (principally genus and family of the main groups of macroinvertebrates were collected. Measured richness and family richness were the best metric followed by Biological Monitoring Working Party/Colombia (BMWP/Col, Odonata richness, Shannon-Weiner, and EPT richness (Ephemeroptera + Plecoptera + Trichoptera indices. Only a slight right trend (Ephemeroptera, Trichoptera, and Chironomidae attributes or incorrect performances (Average Score Per Taxon (ASPT and % EPT were showed by frequently used metrics. Finally, several recommendations were made about taxonomic level used, the ranks of quality of taxa richness, and the effort-results relationship in the field of bioindication.

  2. Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields

    Directory of Open Access Journals (Sweden)

    ALANA C.D. WANDSCHEER

    Full Text Available ABSTRACT The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

  3. Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields.

    Science.gov (United States)

    Wandscheer, Alana C D; Marchesan, Enio; Santos, Sandro; Zanella, Renato; Silva, Marília F; Londero, Guilherme P; Donato, Gabriel

    2017-01-01

    The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

  4. Interval estimation methods of the mean in small sample situation and the results' comparison

    International Nuclear Information System (INIS)

    Wu Changli; Guo Chunying; Jiang Meng; Lin Yuangen

    2009-01-01

    The methods of the sample mean's interval estimation, namely the classical method, the Bootstrap method, the Bayesian Bootstrap method, the Jackknife method and the spread method of the Empirical Characteristic distribution function are described. Numerical calculation on the samples' mean intervals is carried out where the numbers of the samples are 4, 5, 6 respectively. The results indicate the Bootstrap method and the Bayesian Bootstrap method are much more appropriate than others in small sample situation. (authors)

  5. Sampling in Qualitative Research: Rationale, Issues, and Methods

    OpenAIRE

    LUBORSKY, MARK R.; RUBINSTEIN, ROBERT L.

    1995-01-01

    In gerontology the most recognized and elaborate discourse about sampling is generally thought to be in quantitative research associated with survey research and medical research. But sampling has long been a central concern in the social and humanistic inquiry, albeit in a different guise suited to the different goals. There is a need for more explicit discussion of qualitative sampling issues. This article will outline the guiding principles and rationales, features, and practices of sampli...

  6. A comparison of four gravimetric fine particle sampling methods.

    Science.gov (United States)

    Yanosky, J D; MacIntosh, D L

    2001-06-01

    A study was conducted to compare four gravimetric methods of measuring fine particle (PM2.5) concentrations in air: the BGI, Inc. PQ200 Federal Reference Method PM2.5 (FRM) sampler; the Harvard-Marple Impactor (HI); the BGI, Inc. GK2.05 KTL Respirable/Thoracic Cyclone (KTL); and the AirMetrics MiniVol (MiniVol). Pairs of FRM, HI, and KTL samplers and one MiniVol sampler were collocated and 24-hr integrated PM2.5 samples were collected on 21 days from January 6 through April 9, 2000. The mean and standard deviation of PM2.5 levels from the FRM samplers were 13.6 and 6.8 microg/m3, respectively. Significant systematic bias was found between mean concentrations from the FRM and the MiniVol (1.14 microg/m3, p = 0.0007), the HI and the MiniVol (0.85 microg/m3, p = 0.0048), and the KTL and the MiniVol (1.23 microg/m3, p = 0.0078) according to paired t test analyses. Linear regression on all pairwise combinations of the sampler types was used to evaluate measurements made by the samplers. None of the regression intercepts was significantly different from 0, and only two of the regression slopes were significantly different from 1, that for the FRM and the MiniVol [beta1 = 0.91, 95% CI (0.83-0.99)] and that for the KTL and the MiniVol [beta1 = 0.88, 95% CI (0.78-0.98)]. Regression R2 terms were 0.96 or greater between all pairs of samplers, and regression root mean square error terms (RMSE) were 1.65 microg/m3 or less. These results suggest that the MiniVol will underestimate measurements made by the FRM, the HI, and the KTL by an amount proportional to PM2.5 concentration. Nonetheless, these results indicate that all of the sampler types are comparable if approximately 10% variation on the mean levels and on individual measurement levels is considered acceptable and the actual concentration is within the range of this study (5-35 microg/m3).

  7. Assessment of benthic macroinvertebrates at Nile tilapia production using artificial substrate samplers

    Directory of Open Access Journals (Sweden)

    M. S. G. Moura e Silva

    Full Text Available Abstract Biomonitoring is a cheap and effective tool for evaluation of water quality, and infer on the balance of aquatic ecosystems. The benthic macroinvertebrates are bioindicators sensitive to environmental changes, and can assist in detecting and preventing impacts such as organic enrichment and imbalance in the food chain. We compared the structure of benthic communities on artificial substrate samplers located in places near and far from net cages for production of Nile tilapia (Oreochromis niloticus. Samplers were manufactured with nylon net, using substrates such as crushed stone, gravel, loofah and cattail leaves. Samples were collected after 30 days of colonization, rinsed and then the specimens were identified and quantified. The following metrics were calculated: richness of Operational Taxonomic Units, Margalef richness, abundance of individuals, Shannon index and evenness index. The macrobenthic community structure was strongly modified according to the proximity of the net cages. Metrics showed significant differences (p < 0.05 between near and distant sites, for both periods (dry and rainy seasons. The position of the samplers significantly affected the structure of macroinvertebrate community, as near sites showed higher values for the community metrics, such as richness and diversity. Near sites presented a larger number of individuals, observed both in the dry and rainy seasons, with a predominance of Chironomidae (Diptera in the dry season and Tubificidae (Oligochaeta in the rainy season.

  8. Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

    International Nuclear Information System (INIS)

    Gerhardt, A.; Janssens de Bisthoven, L.; Soares, A.M.V.M.

    2004-01-01

    The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor[reg], based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC 50 -48 h: pH-AMD=5.8) and a pH- dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC 50 -48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed. - Toxicity of acid mine drainage was evaluated by macroinvertebrate bioassessment and a new on-line rapid behavioural toxicity test with Atyaephyra desmaresti (Crustacea)

  9. Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, A.; Janssens de Bisthoven, L.; Soares, A.M.V.M

    2004-07-01

    The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor[reg], based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC{sub 50}-48 h: pH-AMD=5.8) and a pH- dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC{sub 50}-48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed. - Toxicity of acid mine drainage was evaluated by macroinvertebrate bioassessment and a new on-line rapid behavioural toxicity test with Atyaephyra desmaresti (Crustacea)

  10. A comparison of different biotic indices based on benthic macro-invertebrates in italian lakes

    Directory of Open Access Journals (Sweden)

    Laura MARZIALI

    2011-02-01

    Full Text Available Benthic macroinvertebrates samples were taken from Italian lakes with different geological, morphological and chemical characteristics. Thirty-two lowland small and large lakes sampled using a grab in soft substrate were selected to develop biotic indices. Diversity indices based on species numbers - abundances and indices using species sensitivity values were compared. The lakes selected were all situated in the Alpine Ecoregion below 800 m a.s.l. and had similar chemical composition but different levels of anthropogenic pressure. Lakes with data available in different years were included as separate lakes in the analysis; littoralsublittoral samples of large lakes were also separated from profundal samples yielding a total of 41 sites for analysis. Seven different biotic indices were compared: (1 Shannon diversity index (H, (2 weighted Shannon diversity index (Hw including in the calculation a sensitivity value assigned to each species, (3 a benthic quality index based on means of three different environmental variables, measuring trophic status, weighted by species abundances (BQITS, (4 an index based on weighted means using a larger set of environmental variables (BQIENV, (5 a modified BQITS, which included both species numbers and total abundance of individuals (BQIES, (6 an index calculated according to a rarefaction method (ES, (7 an index considering indicator species based on experts judgment (BQIEJ. The indices were compared with a trophic status index (TSI constructed by joining three environmental variables: O2% saturation in the hypolimnion during summer stratification, total phosphorous and transparency during full circulation. Comparisons were also made with another environmental stress index (ENI constructed on a larger number of variables. All the biotic indices had significant correlations with both TSI and ENI. BQIES, WFD compliant and well correlated with TSI and ENI, was selected to tentatively assign the investigated lakes

  11. On-line sample processing methods in flow analysis

    DEFF Research Database (Denmark)

    Miró, Manuel; Hansen, Elo Harald

    2008-01-01

    In this chapter, the state of the art of flow injection and related approaches thereof for automation and miniaturization of sample processing regardless of the aggregate state of the sample medium is overviewed. The potential of the various generation of flow injection for implementation of in...

  12. Acoustically levitated droplets: a contactless sampling method for fluorescence studies.

    Science.gov (United States)

    Leiterer, Jork; Grabolle, Markus; Rurack, Knut; Resch-Genger, Ute; Ziegler, Jan; Nann, Thomas; Panne, Ulrich

    2008-01-01

    Acoustic levitation is used as a new tool to study concentration-dependent processes in fluorescence spectroscopy. With this technique, small amounts of liquid and solid samples can be measured without the need for sample supports or containers, which often limits signal acquisition and can even alter sample properties due to interactions with the support material. We demonstrate that, because of the small sample volume, fluorescence measurements at high concentrations of an organic dye are possible without the limitation of inner-filter effects, which hamper such experiments in conventional, cuvette-based measurements. Furthermore, we show that acoustic levitation of liquid samples provides an experimentally simple way to study distance-dependent fluorescence modulations in semiconductor nanocrystals. The evaporation of the solvent during levitation leads to a continuous increase of solute concentration and can easily be monitored by laser-induced fluorescence.

  13. Using a Geospatial Model to Relate Fluvial Geomorphology to Macroinvertebrate Habitat in a Prairie River—Part 1: Genus-Level Relationships with Geomorphic Typologies

    Directory of Open Access Journals (Sweden)

    Anna G. N. Meissner

    2016-01-01

    Full Text Available Modern river ecosystems undergo constant stress from disturbances such as bank stabilization, channelization, dams, and municipal, agricultural, and industrial water use. As these anthropogenic water requirements persist, more efficient methods of characterizing river reaches are essential. Benthic macroinvertebrates are helpful when evaluating fluvial health, because they are often the first group to react to contaminants that can then be transferred through them to other trophic levels. Hence, the purpose of this research is to use a geospatial model to differentiate instream macroinvertebrate habitats, and determine if the model is a viable method for stream evaluation. Through the use of ArcGIS and digital elevation models, the fluvial geomorphology of the Qu’Appelle River in Saskatchewan (SK was assessed. Four geomorphological characteristics of the river were isolated (sinuosity, slope, fractal dimension, and stream width and clustered through Principle Component Analysis (PCA, yielding sets of river reaches with similar geomorphological characteristics, called typologies. These typologies were mapped to form a geospatial model of the river. Macroinvertebrate data were aligned to the locations of the typologies, revealing several relationships with the fluvial geomorphology. A Kruskal-Wallis analysis and post hoc pairwise multiple comparisons were completed with the macroinvertebrate data to pinpoint significant genera, as related to the geospatial model.

  14. Assessment of Ecological Quality of the Tajan River in Iran Using a Multimetric Macroinvertebrate Index and Species Traits

    Science.gov (United States)

    Aazami, Jaber; Esmaili Sari, Abbas; Abdoli, Asghar; Sohrabi, Hormoz; Van den Brink, Paul J.

    2015-07-01

    The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were obtained for 17 sites. The Shahid-Rajaie dam divides the Tajan River into an up- and downstream part, with different land uses. Eighteen metrics were used to represent four components of ecosystem quality, including tolerance (Hilsenhoff, SIGNAL), diversity (Margalef, Shannon-Wiener, Simpson, and Evenness), abundance (total number of taxa, individuals, Ephemeroptera, Plecoptera, Trichoptera, EPT, and Insects), and composition of assemblages (% Ephemeroptera, % Plecoptera, % Trichoptera, and % EPT Taxa). The integrated MMI was calculated by averaging the obtained scores of all indices. In the next step, we gathered information on 22 biological traits of macroinvertebrates to evaluate whether (group of) traits could be identified that are indicative for specific or general stress. Result showed a decrease in MMI from upstream (very good water quality) to downstream (bad) due to human activities. Industrial activities like pulping and papermaking operations or sand mining in the downstream part had more effects than agriculture and fish ponds in the upstream part. A redundancy analysis biplot showed the variation between the modalities of trait of macroinvertebrates and their correlation with physico-chemical parameters in Tajan River. The findings show that traits can be indicative for different kind of stress but that more effort has to be put in gathering data sets to disentangle the effect of habitat quality, pollution, and the physico-chemical properties of high- versus lowland rivers.

  15. Method for Hot Real-Time Sampling of Gasification Products

    Energy Technology Data Exchange (ETDEWEB)

    Pomeroy, Marc D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-29

    The Thermochemical Process Development Unit (TCPDU) at the National Renewable Energy Laboratory (NREL) is a highly instrumented half-ton/day pilot scale plant capable of demonstrating industrially relevant thermochemical technologies from lignocellulosic biomass conversion, including gasification. Gasification creates primarily Syngas (a mixture of Hydrogen and Carbon Monoxide) that can be utilized with synthesis catalysts to form transportation fuels and other valuable chemicals. Biomass derived gasification products are a very complex mixture of chemical components that typically contain Sulfur and Nitrogen species that can act as catalysis poisons for tar reforming and synthesis catalysts. Real-time hot online sampling techniques, such as Molecular Beam Mass Spectrometry (MBMS), and Gas Chromatographs with Sulfur and Nitrogen specific detectors can provide real-time analysis providing operational indicators for performance. Sampling typically requires coated sampling lines to minimize trace sulfur interactions with steel surfaces. Other materials used inline have also shown conversion of sulfur species into new components and must be minimized. Sample line Residence time within the sampling lines must also be kept to a minimum to reduce further reaction chemistries. Solids from ash and char contribute to plugging and must be filtered at temperature. Experience at NREL has shown several key factors to consider when designing and installing an analytical sampling system for biomass gasification products. They include minimizing sampling distance, effective filtering as close to source as possible, proper line sizing, proper line materials or coatings, even heating of all components, minimizing pressure drops, and additional filtering or traps after pressure drops.

  16. Assessment of river quality in a subtropical Austral river system: a combined approach using benthic diatoms and macroinvertebrates

    Science.gov (United States)

    Nhiwatiwa, Tamuka; Dalu, Tatenda; Sithole, Tatenda

    2017-12-01

    River systems constitute areas of high human population densities owing to their favourable conditions for agriculture, water supply and transportation network. Despite human dependence on river systems, anthropogenic activities severely degrade water quality. The main aim of this study was to assess the river health of Ngamo River using diatom and macroinvertebrate community structure based on multivariate analyses and community metrics. Ammonia, pH, salinity, total phosphorus and temperature were found to be significantly different among the study seasons. The diatom and macroinvertebrate taxa richness increased downstream suggesting an improvement in water as we moved away from the pollution point sources. Canonical correspondence analyses identified nutrients (total nitrogen and reactive phosphorus) as important variables structuring diatom and macroinvertebrate community. The community metrics and diversity indices for both bioindicators highlighted that the water quality of the river system was very poor. These findings indicate that both methods can be used for water quality assessments, e.g. sewage and agricultural pollution, and they show high potential for use during water quality monitoring programmes in other regions.

  17. Reliability of a method of sampling stream invertebrates

    CSIR Research Space (South Africa)

    Chutter, FM

    1966-05-01

    Full Text Available In field ecological studies inferences must often be drawn from dissimilarities in numbers and species of organisms found in biological samples collected at different times and under various conditions....

  18. Summary Report for Evaluation of Compost Sample Drying Methods

    National Research Council Canada - National Science Library

    Frye, Russell

    1994-01-01

    .... Previous work in Support of these efforts developed a compost sample preparation scheme, consisting of air drying followed by milling, to reduce analytical variability in the heterogeneous compost matrix...

  19. Effects of an oil spill on leafpack-inhabiting macroinvertebrates in the Chariton river, Missouri

    Science.gov (United States)

    Poulton, B.C.; Callahan, E.V.; Hurtubise, R.D.; Mueller, B.G.

    1998-01-01

    Artificial leaf packs were used to determine the effects of an oil spill on stream macroinvertebrate communities in the Chariton River, Missouri. Plastic mesh leaf retainers with approximately 10 g of leaves from five tree species were deployed at five sites (two upstream of the spill and three downstream) immediately after the spill and one year later. Four macroinvertebrate species dominating the community at upstream sites were virtually eliminated below the spill, including the stonefly Isoperla bilineata, the caddisfly Potamyia flava, the midge Thienemanniella xena, and blackfly larvae (Simulium sp.). Density of collector and shredder functional groups, and number of shredder taxa differed between upstream sites and the two furthest downstream sites during the 1990 sample period (Kruskal-Wallis w/Bonferroni paired comparisons, experiment wise error rate = 0.05). With one exception, no differences between sites were detected in the 1991-1992 sample period, indicating that the benthic community had at least partially recovered from the oil spill after one year. The odds of obtaining a sample with a small abundance of shredders (abundance < median) in 1990 was significantly greater downstream of the spill than upstream, and the odds of obtaining a sample with a small abundance of shredders at downstream sites was greater in 1990 than in 1991-1992. A similar pattern was observed in abundance and taxa richness of the collector functional group. No significant differences between the two sampling periods were detected at upstream sites. Observed effects appeared to be associated with oil sorption and substrate coating, creating conditions unsuitable for successful colonization.

  20. The effect of sample preparation methods on glass performance

    International Nuclear Information System (INIS)

    Oh, M.S.; Oversby, V.M.

    1990-01-01

    A series of experiments was conducted using SRL 165 synthetic waste glass to investigate the effects of surface preparation and leaching solution composition on the alteration of the glass. Samples of glass with as-cast surfaces produced smooth reaction layers and some evidence for precipitation of secondary phases from solution. Secondary phases were more abundant in samples reacted in deionized water than for those reacted in a silicate solution. Samples with saw-cut surfaces showed a large reduction in surface roughness after 7 days of reaction in either solution. Reaction in silicate solution for up to 91 days produced no further change in surface morphology, while reaction in DIW produced a spongy surface that formed the substrate for further surface layer development. The differences in the surface morphology of the samples may create microclimates that control the details of development of alteration layers on the glass; however, the concentrations of elements in leaching solutions show differences of 50% or less between samples prepared with different surface conditions for tests of a few months duration. 6 refs., 7 figs., 1 tab

  1. Statistical Methods and Tools for Hanford Staged Feed Tank Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Fountain, Matthew S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brigantic, Robert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Peterson, Reid A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-10-01

    This report summarizes work conducted by Pacific Northwest National Laboratory to technically evaluate the current approach to staged feed sampling of high-level waste (HLW) sludge to meet waste acceptance criteria (WAC) for transfer from tank farms to the Hanford Waste Treatment and Immobilization Plant (WTP). The current sampling and analysis approach is detailed in the document titled Initial Data Quality Objectives for WTP Feed Acceptance Criteria, 24590-WTP-RPT-MGT-11-014, Revision 0 (Arakali et al. 2011). The goal of this current work is to evaluate and provide recommendations to support a defensible, technical and statistical basis for the staged feed sampling approach that meets WAC data quality objectives (DQOs).

  2. Method for validating radiobiological samples using a linear accelerator

    International Nuclear Information System (INIS)

    Brengues, Muriel; Liu, David; Korn, Ronald; Zenhausern, Frederic

    2014-01-01

    There is an immediate need for rapid triage of the population in case of a large scale exposure to ionizing radiation. Knowing the dose absorbed by the body will allow clinicians to administer medical treatment for the best chance of recovery for the victim. In addition, today's radiotherapy treatment could benefit from additional information regarding the patient's sensitivity to radiation before starting the treatment. As of today, there is no system in place to respond to this demand. This paper will describe specific procedures to mimic the effects of human exposure to ionizing radiation creating the tools for optimization of administered radiation dosimetry for radiotherapy and/or to estimate the doses of radiation received accidentally during a radiation event that could pose a danger to the public. In order to obtain irradiated biological samples to study ionizing radiation absorbed by the body, we performed ex-vivo irradiation of human blood samples using the linear accelerator (LINAC). The LINAC was implemented and calibrated for irradiating human whole blood samples. To test the calibration, a 2 Gy test run was successfully performed on a tube filled with water with an accuracy of 3% in dose distribution. To validate our technique the blood samples were ex-vivo irradiated and the results were analyzed using a gene expression assay to follow the effect of the ionizing irradiation by characterizing dose responsive biomarkers from radiobiological assays. The response of 5 genes was monitored resulting in expression increase with the dose of radiation received. The blood samples treated with the LINAC can provide effective irradiated blood samples suitable for molecular profiling to validate radiobiological measurements via the gene-expression based biodosimetry tools. (orig.)

  3. Method for validating radiobiological samples using a linear accelerator.

    Science.gov (United States)

    Brengues, Muriel; Liu, David; Korn, Ronald; Zenhausern, Frederic

    2014-04-29

    There is an immediate need for rapid triage of the population in case of a large scale exposure to ionizing radiation. Knowing the dose absorbed by the body will allow clinicians to administer medical treatment for the best chance of recovery for the victim. In addition, today's radiotherapy treatment could benefit from additional information regarding the patient's sensitivity to radiation before starting the treatment. As of today, there is no system in place to respond to this demand. This paper will describe specific procedures to mimic the effects of human exposure to ionizing radiation creating the tools for optimization of administered radiation dosimetry for radiotherapy and/or to estimate the doses of radiation received accidentally during a radiation event that could pose a danger to the public. In order to obtain irradiated biological samples to study ionizing radiation absorbed by the body, we performed ex-vivo irradiation of human blood samples using the linear accelerator (LINAC). The LINAC was implemented and calibrated for irradiating human whole blood samples. To test the calibration, a 2 Gy test run was successfully performed on a tube filled with water with an accuracy of 3% in dose distribution. To validate our technique the blood samples were ex-vivo irradiated and the results were analyzed using a gene expression assay to follow the effect of the ionizing irradiation by characterizing dose responsive biomarkers from radiobiological assays. The response of 5 genes was monitored resulting in expression increase with the dose of radiation received. The blood samples treated with the LINAC can provide effective irradiated blood samples suitable for molecular profiling to validate radiobiological measurements via the gene-expression based biodosimetry tools.

  4. A One-Sample Test for Normality with Kernel Methods

    OpenAIRE

    Kellner , Jérémie; Celisse , Alain

    2015-01-01

    We propose a new one-sample test for normality in a Reproducing Kernel Hilbert Space (RKHS). Namely, we test the null-hypothesis of belonging to a given family of Gaussian distributions. Hence our procedure may be applied either to test data for normality or to test parameters (mean and covariance) if data are assumed Gaussian. Our test is based on the same principle as the MMD (Maximum Mean Discrepancy) which is usually used for two-sample tests such as homogeneity or independence testing. O...

  5. Comparison of indoor air sampling and dust collection methods for fungal exposure assessment using quantitative PCR

    Science.gov (United States)

    Evaluating fungal contamination indoors is complicated because of the many different sampling methods utilized. In this study, fungal contamination was evaluated using five sampling methods and four matrices for results. The five sampling methods were a 48 hour indoor air sample ...

  6. 40 CFR 80.8 - Sampling methods for gasoline and diesel fuel.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Sampling methods for gasoline and... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES General Provisions § 80.8 Sampling methods for gasoline and diesel fuel. The sampling methods specified in this section shall be used to collect samples...

  7. Rapid methods for measuring radionuclides in food and environmental samples

    International Nuclear Information System (INIS)

    Perkins, Richard W.

    1995-01-01

    The application of ICP/mass spectrometry for the isotopic analysis of environmental samples, the use of drum assayers for measuring radionuclides in food and a rapid procedure for the measurement of the transuranic elements and thorium, performed at the Pacific Northwest Laboratory are discussed

  8. Modern methods of sample preparation for GC analysis

    NARCIS (Netherlands)

    de Koning, S.; Janssen, H.-G.; Brinkman, U.A.Th.

    2009-01-01

    Today, a wide variety of techniques is available for the preparation of (semi-) solid, liquid and gaseous samples, prior to their instrumental analysis by means of capillary gas chromatography (GC) or, increasingly, comprehensive two-dimensional GC (GC × GC). In the past two decades, a large number

  9. an assessment of methods for sampling carabid beetles

    African Journals Online (AJOL)

    Mgina

    collection of epigaeic (ground-dwelling) invertebrates (Southwood and Henderson,. 2000). It has been widely used for sampling carabid beetles in biodiversity inventories. (Niemela et al. 1994, Davies 2000, Nyundo. 2002), population and community ecology. (Greenslade 1968, Refseth, 1980,. Niemela1988, Niemela et al.

  10. Post-Decontamination Vapor Sampling and Analytical Test Methods

    Science.gov (United States)

    2015-08-12

    is decontaminated that could pose an exposure hazard to unprotected personnel. The chemical contaminants may include chemical warfare agents (CWAs... decontamination process. Chemical contaminants can include chemical warfare agents (CWAs) or their simulants, nontraditional agents (NTAs), toxic industrial...a range of test articles from coupons, panels, and small fielded equipment items. 15. SUBJECT TERMS Vapor hazard; vapor sampling; chemical warfare

  11. An Importance Sampling Simulation Method for Bayesian Decision Feedback Equalizers

    OpenAIRE

    Chen, S.; Hanzo, L.

    2000-01-01

    An importance sampling (IS) simulation technique is presented for evaluating the lower-bound bit error rate (BER) of the Bayesian decision feedback equalizer (DFE) under the assumption of correct decisions being fed back. A design procedure is developed, which chooses appropriate bias vectors for the simulation density to ensure asymptotic efficiency of the IS simulation.

  12. Stream habitat structure influences macroinvertebrate response to pesticides

    DEFF Research Database (Denmark)

    Rasmussen, Jes; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette

    2012-01-01

    Agricultural pesticide contamination in surface waters is increasingly threatening to impair the surface water ecosystems. Agricultural streams are furthermore often heavily maintained to optimise the transport of water away from fields. The physical habitat degradation that result from heavy...... stream maintenance probably introduce additional stress that may act in concert with pesticide stress. We surveyed pesticide contamination and macroinvertebrate community structure in 14 streams along a gradient of expected pesticide exposure. A paired-reach approach was applied to differentiate...... the effects of pesticides between sites with degraded and more undisturbed physical properties. The effect of pesticides on macroinvertebrate communities (measured as the relative abundance of SPEcies At Risk) was increased at stream sites with degraded physical habitats primarily due to the absence...

  13. Vegetation Sampling for Wetland Delineation: A Review and Synthesis of Methods and Sampling Issues

    Science.gov (United States)

    2010-07-01

    which trees are sampled via use of an angle gauge or basal area prism (Husch et al. 2003; Packard and Radtke 2007). Basal area data can be used to...refuges from fungal pathogens for seeds of eastern hemlock (Tsuga canadensis). Ecology 85(1): 284– 289. Packard, K. C., and P. J. Radtke . 2007. Forest

  14. Method for Hot Real-Time Sampling of Pyrolysis Vapors

    Energy Technology Data Exchange (ETDEWEB)

    Pomeroy, Marc D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-29

    Biomass Pyrolysis has been an increasing topic of research, in particular as a replacement for crude oil. This process utilizes moderate temperatures to thermally deconstruct the biomass which is then condensed into a mixture of liquid oxygenates to be used as fuel precursors. Pyrolysis oils contain more than 400 compounds, up to 60 percent of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during the condensation and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors, many challenges must be overcome. Sampling must occur within a narrow range of temperatures to reduce product composition changes from overheating or partial condensation or plugging of lines from condensed products. Residence times must be kept at a minimum to reduce further reaction chemistries. Pyrolysis vapors also form aerosols that are carried far downstream and can pass through filters resulting in build-up in downstream locations. The co-produced bio-char and ash from the pyrolysis process can lead to plugging of the sample lines, and must be filtered out at temperature, even with the use of cyclonic separators. A practical approach for considerations and sampling system design, as well as lessons learned are integrated into the hot analytical sampling system of the National Renewable Energy Laboratory's (NREL) Thermochemical Process Development Unit (TCPDU) to provide industrially relevant demonstrations of thermochemical transformations of biomass feedstocks at the pilot scale.

  15. Sampling pig farms at the abattoir in a cross-sectional study - Evaluation of a sampling method.

    Science.gov (United States)

    Birkegård, Anna Camilla; Halasa, Tariq; Toft, Nils

    2017-09-15

    A cross-sectional study design is relatively inexpensive, fast and easy to conduct when compared to other study designs. Careful planning is essential to obtaining a representative sample of the population, and the recommended approach is to use simple random sampling from an exhaustive list of units in the target population. This approach is rarely feasible in practice, and other sampling procedures must often be adopted. For example, when slaughter pigs are the target population, sampling the pigs on the slaughter line may be an alternative to on-site sampling at a list of farms. However, it is difficult to sample a large number of farms from an exact predefined list, due to the logistics and workflow of an abattoir. Therefore, it is necessary to have a systematic sampling procedure and to evaluate the obtained sample with respect to the study objective. We propose a method for 1) planning, 2) conducting, and 3) evaluating the representativeness and reproducibility of a cross-sectional study when simple random sampling is not possible. We used an example of a cross-sectional study with the aim of quantifying the association of antimicrobial resistance and antimicrobial consumption in Danish slaughter pigs. It was not possible to visit farms within the designated timeframe. Therefore, it was decided to use convenience sampling at the abattoir. Our approach was carried out in three steps: 1) planning: using data from meat inspection to plan at which abattoirs and how many farms to sample; 2) conducting: sampling was carried out at five abattoirs; 3) evaluation: representativeness was evaluated by comparing sampled and non-sampled farms, and the reproducibility of the study was assessed through simulated sampling based on meat inspection data from the period where the actual data collection was carried out. In the cross-sectional study samples were taken from 681 Danish pig farms, during five weeks from February to March 2015. The evaluation showed that the sampling

  16. Benthic macroinvertebrates as bioindicators of water quality in an Atlantic forest fragment

    Directory of Open Access Journals (Sweden)

    Augusto Oliveira

    2010-12-01

    Full Text Available The objective of this study was to evaluate benthic macroinvertebrate communities as bioindicators of water quality in five streams located in the "Reserva Particular do Patrimônio Natural" (RPPN Mata Samuel de Paula and its surroundings, in the municipality of Nova Lima near the city of Belo Horizonte, Minas Gerais State, southeastern Brazil. This region has been strongly modified by human activities including mining and urbanization. Samples were collected in the field every three months between August 2004 and November 2005, totaling six samplings in the rainy and dry seasons. This assessment identified one area ecologically altered while the other sampling sites were found to be minimally disturbed systems, with well-preserved ecological conditions. However, according to the Biological Monitoring Work Party (BMWP and the Average Score Per Taxon (ASPT indices, all sampling sites had excellent water quality. A total of 14,952 organisms was collected, belonging to 155 taxa (148 Insecta, two Annelida, one Bivalvia, one Decapoda, one Planariidae, one Hydracarina, and one Entognatha. The most abundant benthic groups were Chironomidae (47.9%, Simuliidae (12.3%, Bivalvia (7.5%, Decapoda (6.1%, Oligochaeta (5.2%, Polycentropodidae (3.7%, Hydropsychidae (2.5%, Calamoceratidae (1.8%, Ceratopogonidae (1.7%, and Libellulidae (1.2%. The assessment of the benthic functional feeding groups showed that 34% of the macroinvertebrates were collector-gatherers, 29% predators, 24% collector-filterers, 8% shredders, and 5% scrapers. The RPPN Mata Samuel de Paula comprises diversified freshwater habitats that are of great importance for the conservation of many benthic taxa that are intolerant to organic pollution.

  17. [Effects of cascading hydropower dams operation on the structure and distribution pattern of benthic macroinvertebrate assemblages in Manwan Reservoir, Southwest China].

    Science.gov (United States)

    Li, Jin Peng; Dong, Shi Kui; Peng, Ming Chun; Wu, Xuan; Zhou, Fang; Yu, Yin

    2017-12-01

    Benthic macroinvertebrate assemblages are one of the biological groups in aquatic ecosystem most sensitive to the habitat change and degradation, and can be a biological indicator for the aquatic ecosystem change and succession in cascading hydropower dam reservoir. The middle and lower reaches of the Lancang River are key spot for international biodiversity conservation and ecological studies on the effects of cascading hydropower dam exploitation. In this study, the reservoir of Manwan hydropower dam, the first dam in Lancang-Mekong river main stream, was selected as the study site. The benthic macroinvertebrate assemblages were sampled in 2011 and 2016 respectively. Meanwhile, the survey data before impounding (natural river, 1996) and early stage of single dam (1997) were collected to conduct the overall analysis for structure, distribution pattern and evolution of benthic macroinvertebrate assemblages. The results showed that the dominant biological group was gradually changed from the Oligochaeta and Insecta to the Mollusca. Along the longitudinal gradient, the density and biomass of the benthic macroinvertebrate assemblages were remarkably increased in reservoir, especially in the lacustrine zone. As for the functional feeding group, the predator and gatherer-collector changed into filter-collector predominantly in lacustrine zone. With the cascading dams operation, the biotic index indicated that the water quality of reservoir in 2016 was better than in 2011. The evolution of benthic macroinvertebrate assemblages in the Manwan Reservoir was related to the operation of Xiaowan dam in the upper reach, the hydrological regime and siltation in the reservoir, and would continue with dynamic changes with the operation of the cascading hydropower dam.

  18. Littoral macroinvertebrates of acidified lakes in the Bohemian Forest

    Czech Academy of Sciences Publication Activity Database

    Ungermanová, L.; Kolaříková, K.; Stuchlík, E.; Senoo, T.; Horecký, J.; Kopáček, Jiří; Chvojka, P.; Tátosová, J.; Bitušík, P.; Fjellheim, A.

    2014-01-01

    Roč. 69, č. 9 (2014), s. 1190-1201 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA526/09/0567; GA ČR(CZ) GA206/07/1200 Grant - others:EC(XE) EURO-LIMPACS GOCE-CT-2003-505540 Institutional support: RVO:60077344 Keywords : lakes * macroinvertebrates * acidification * recovery * forest catchment Subject RIV: DJ - Water Pollution ; Quality Impact factor: 0.827, year: 2014

  19. Method for spiking soil samples with organic compounds

    DEFF Research Database (Denmark)

    Brinch, Ulla C; Ekelund, Flemming; Jacobsen, Carsten S

    2002-01-01

    We examined the harmful side effects on indigenous soil microorganisms of two organic solvents, acetone and dichloromethane, that are normally used for spiking of soil with polycyclic aromatic hydrocarbons for experimental purposes. The solvents were applied in two contamination protocols to either...... higher than in control soil, probably due mainly to release of predation from indigenous protozoa. In order to minimize solvent effects on indigenous soil microorganisms when spiking native soil samples with compounds having a low water solubility, we propose a common protocol in which the contaminant...... tagged with luxAB::Tn5. For both solvents, application to the whole sample resulted in severe side effects on both indigenous protozoa and bacteria. Application of dichloromethane to the whole soil volume immediately reduced the number of protozoa to below the detection limit. In one of the soils...

  20. Exploring biomolecular dynamics and interactions using advanced sampling methods

    International Nuclear Information System (INIS)

    Luitz, Manuel; Bomblies, Rainer; Ostermeir, Katja; Zacharias, Martin

    2015-01-01

    Molecular dynamics (MD) and Monte Carlo (MC) simulations have emerged as a valuable tool to investigate statistical mechanics and kinetics of biomolecules and synthetic soft matter materials. However, major limitations for routine applications are due to the accuracy of the molecular mechanics force field and due to the maximum simulation time that can be achieved in current simulations studies. For improving the sampling a number of advanced sampling approaches have been designed in recent years. In particular, variants of the parallel tempering replica-exchange methodology are widely used in many simulation studies. Recent methodological advancements and a discussion of specific aims and advantages are given. This includes improved free energy simulation approaches and conformational search applications. (topical review)

  1. Sample preparation method for induced mutation on orchid

    International Nuclear Information System (INIS)

    Suhaimi Musa; Sakinah Ariffin

    2005-01-01

    Studies on the induction of mutation in Dendrobium orchid at MINT has produced a number of new orchid mutant cultivars. Tissue culture techniques on orchid seeds and meristem cloning are employed in preparing the samples for the mutation induction. Solid medium based on the Murashige and Skoog (1962) and liquid medium based on Vacin and Went (1949) were found to be suitable in producing protocorm like bodies (PLBs) that are required for the irradiation treatment. (Author)

  2. Sample Size Calculations for Population Size Estimation Studies Using Multiplier Methods With Respondent-Driven Sampling Surveys.

    Science.gov (United States)

    Fearon, Elizabeth; Chabata, Sungai T; Thompson, Jennifer A; Cowan, Frances M; Hargreaves, James R

    2017-09-14

    While guidance exists for obtaining population size estimates using multiplier methods with respondent-driven sampling surveys, we lack specific guidance for making sample size decisions. To guide the design of multiplier method population size estimation studies using respondent-driven sampling surveys to reduce the random error around the estimate obtained. The population size estimate is obtained by dividing the number of individuals receiving a service or the number of unique objects distributed (M) by the proportion of individuals in a representative survey who report receipt of the service or object (P). We have developed an approach to sample size calculation, interpreting methods to estimate the variance around estimates obtained using multiplier methods in conjunction with research into design effects and respondent-driven sampling. We describe an application to estimate the number of female sex workers in Harare, Zimbabwe. There is high variance in estimates. Random error around the size estimate reflects uncertainty from M and P, particularly when the estimate of P in the respondent-driven sampling survey is low. As expected, sample size requirements are higher when the design effect of the survey is assumed to be greater. We suggest a method for investigating the effects of sample size on the precision of a population size estimate obtained using multipler methods and respondent-driven sampling. Uncertainty in the size estimate is high, particularly when P is small, so balancing against other potential sources of bias, we advise researchers to consider longer service attendance reference periods and to distribute more unique objects, which is likely to result in a higher estimate of P in the respondent-driven sampling survey. ©Elizabeth Fearon, Sungai T Chabata, Jennifer A Thompson, Frances M Cowan, James R Hargreaves. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 14.09.2017.

  3. Improvement of correlated sampling Monte Carlo methods for reactivity calculations

    International Nuclear Information System (INIS)

    Nakagawa, Masayuki; Asaoka, Takumi

    1978-01-01

    Two correlated Monte Carlo methods, the similar flight path and the identical flight path methods, have been improved to evaluate up to the second order change of the reactivity perturbation. Secondary fission neutrons produced by neutrons having passed through perturbed regions in both unperturbed and perturbed systems are followed in a way to have a strong correlation between secondary neutrons in both the systems. These techniques are incorporated into the general purpose Monte Carlo code MORSE, so as to be able to estimate also the statistical error of the calculated reactivity change. The control rod worths measured in the FCA V-3 assembly are analyzed with the present techniques, which are shown to predict the measured values within the standard deviations. The identical flight path method has revealed itself more useful than the similar flight path method for the analysis of the control rod worth. (auth.)

  4. Summary Report for Evaluation of Compost Sample Drying Methods

    National Research Council Canada - National Science Library

    Frye, Russell

    1994-01-01

    The U.S. Army Environmental Center (USAEC), formerly the U.S. Army Toxic and Hazardous Materials Agency, has evaluated composting methods for treatment of explosive-contaminated soils and sediments at Army installations...

  5. The method of Sample Management in Neutron Activation Analysis Laboratory-Serpong

    International Nuclear Information System (INIS)

    Elisabeth-Ratnawati

    2005-01-01

    In the testing laboratory used by neutron activation analysis method, sample preparation is the main factor and it can't be neglect. The error in the sample preparation can give result with lower accuracy. In this article is explained the scheme of sample preparation i.e sample receive administration, the separate of sample, fluid and solid sample preparation, sample grouping, irradiation, sample counting and holding the sample post irradiation. If the management of samples were good application based on Standard Operation Procedure, therefore each samples has good traceability. To optimize the management of samples is needed the trained and skilled personal and good facility. (author)

  6. DEVELOPMENT OF A STREAM BENTHIC MACROINVERTEBRATE INTEGRITY INDEX (SBMII) FOR WADEABLE STREAMS IN THE MID-ATLANTIC HIGHLANDS REGION

    Science.gov (United States)

    The Stream Benthic Macroinvertebrate Integrity Index (SBMII), a multimetric biotic index for assessing biological conditions of wadeable streams, was developed using seven macroinvertebrate metrics (Ephemeroptera richness, Plecoptera richness, Trichoptera richness, Collector-Filt...

  7. Two methods of self-sampling compared to clinician sampling to detect reproductive tract infections in Gugulethu, South Africa

    NARCIS (Netherlands)

    van de Wijgert, Janneke; Altini, Lydia; Jones, Heidi; de Kock, Alana; Young, Taryn; Williamson, Anna-Lise; Hoosen, Anwar; Coetzee, Nicol

    2006-01-01

    To assess the validity, feasibility, and acceptability of 2 methods of self-sampling compared to clinician sampling during a speculum examination. To improve screening for reproductive tract infections (RTIs) in resource-poor settings. In a public clinic in Cape Town, 450 women underwent a speculum

  8. Genetic analysis of bulimia nervosa: methods and sample description.

    Science.gov (United States)

    Kaye, Walter H; Devlin, Bernie; Barbarich, Nicole; Bulik, Cynthia M; Thornton, Laura; Bacanu, Silviu-Alin; Fichter, Manfred M; Halmi, Katherine A; Kaplan, Allan S; Strober, Michael; Woodside, D Blake; Bergen, Andrew W; Crow, Scott; Mitchell, James; Rotondo, Alessandro; Mauri, Mauro; Cassano, Giovanni; Keel, Pamela; Plotnicov, Katherine; Pollice, Christine; Klump, Kelly L; Lilenfeld, Lisa R; Ganjei, J Kelly; Quadflieg, Norbert; Berrettini, Wade H

    2004-05-01

    Twin and family studies suggest that genetic variants contribute to the pathogenesis of bulimia nervosa (BN) and anorexia nervosa (AN). The Price Foundation has supported an international, multisite study of families with these disorders to identify these genetic variations. The current study presents the clinical characteristics of this sample as well as a description of the study methodology. All probands met modified criteria for BN or bulimia nervosa with a history of AN (BAN) as defined in the 4th ed. of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association, 1994). All affected relatives met DSM-IV criteria for BN, AN, BAN, or eating disorders not otherwise specified (EDNOS). Probands and affected relatives were assessed diagnostically using both trained-rater and self-report assessments. DNA samples were collected from probands, affected relatives, and available biologic parents. Assessments were obtained from 163 BN probands and 165 BAN probands. Overall, there were 365 relative pairs available for linkage analysis. Of the affected relatives of BN probands, 62 were diagnosed as BN (34.8%), 49 as BAN (27.5%), 35 as AN (19.7%), and 32 as EDNOS (18.0%). For the relatives of BAN probands, 42 were diagnosed as BN (22.5%), 67 as BAN (35.8%), 48 as AN (25.7%), and 30 as EDNOS (16.0%). This study represents the largest genetic study of eating disorders to date. Clinical data indicate that although there are a large number of individuals with BN disorders, a range of eating pathology is represented in the sample, allowing for the examination of several different phenotypes in molecular genetic analyses. Copyright 2004 by Wiley Periodicals, Inc. Int J Eat Disord 35: 556-570, 2004.

  9. Designing waveforms for temporal encoding using a frequency sampling method

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2007-01-01

    was compared to a linear frequency modulated signal with amplitude tapering, previously used in clinical studies for synthetic transmit aperture imaging. The latter had a relatively flat spectrum which implied that the waveform tried to excite all frequencies including ones with low amplification. The proposed......In this paper a method for designing waveforms for temporal encoding in medical ultrasound imaging is described. The method is based on least squares optimization and is used to design nonlinear frequency modulated signals for synthetic transmit aperture imaging. By using the proposed design method...... waveform, on the other hand, was designed so that only frequencies where the transducer had a large amplification were excited. Hereby, unnecessary heating of the transducer could be avoided and the signal-tonoise ratio could be increased. The experimental ultrasound scanner RASMUS was used to evaluate...

  10. Abundance and diversity of aquatic macroinvertebrate communities in lakes exposed to Chernobyl-derived ionising radiation

    International Nuclear Information System (INIS)

    Murphy, J.F.; Nagorskaya, L.L.; Smith, J.T.

    2011-01-01

    Littoral (lake shore) macroinvertebrate communities were studied in eight natural lakes affected by fallout from the Chernobyl accident. The lakes spanned a range in 137 Cs contamination from 100 to 15500 kBq m -2 and estimated external dose rates ranged from 0.13 to 30.7 μGy h -1 . General linear models were used to assess whether abundance of individuals, taxon richness, Berger-Parker dominance and Shannon-Wiener diversity varied across the lakes. Step-wise multiple regressions were used to relate variation in total abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity, taxon richness within major groups of macroinvertebrates and abundance of the more common individual taxa to the measured environmental characteristics (conductivity, pH, total hardness and phosphate; lake area, lake maximum depth and total external dose) of the lakes. No evidence was found in this study that the ecological status of lake communities has been influenced by radioactive contamination from the Chernobyl accident. Indeed, the most contaminated lake, Glubokoye, contained the highest richness of aquatic invertebrates. Taxon richness in the eight study lakes varied from 22 (Svyatskoe no. 7) to 42 (Glubokoye) which spans a range typical for uncontaminated lakes in the region. Since 90 Sr is readily-absorbed by Mollusca, estimated dose rates to this group exceeded those for other invertebrate groups in two lakes (Perstok and Glubokoye). However this study found no association between mollusc diversity or abundance of individual snail species and variation between lakes in the external radiation dose. Indeed Glubokoye, the lake most contaminated by 90 Sr, had the highest richness of freshwater snails per sample (an average of 8.9 taxa per sample). - Highlights: → We studied the effect of radiation on macroinvertebrates in Chernobyl affected lakes. → Abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity evaluated. → No relationship between

  11. A destructive sample preparation method for radioactive waste characterization

    International Nuclear Information System (INIS)

    Olteanu, M.; Bucur, C.

    2015-01-01

    Acid digestion, using the microwave power, was applied for ''dissolution'' of different materials corresponding to the radioactive waste matrices resulted from a nuclear power plant operation, including exchange resin (cationic and mixed), concrete, paper, textile and activated charcoals. A small aliquot of solid sample (0.1-0.5g) was mixed with a known volume of digestion reagents (HNO3 67% - H2O2 30% or HNO3 67% - HCl 37%, with HF addition if the SiO2 was present in matrices) in a 100 ml PTFE vessel and it was mineralized using a Berghof digestion system, Speedwave 4. Starting from the manufacturer procedures, the technical parameters (temperature and mineralization time), the types and quantities of digestion reagents were optimized. After the mineralization process, the samples were transferred in centrifuge tubes, separated at 3500 rot/min and visually analysed. The obtained solutions were clear, without suspended or deposed materials and separated phases, ready for future separation processes of the ''difficult to measure'' radioisotopes. (authors)

  12. COMPARISON OF LARGE RIVER SAMPLING METHODS ON ALGAL METRICS

    Science.gov (United States)

    We compared the results of four methods used to assess the algal communities at 60 sites distributed among four rivers. Based on Principle Component Analysis of physical habitat data collected concomitantly with the algal data, sites were separated into those with a mean thalweg...

  13. COMPARISON OF LARGE RIVER SAMPLING METHOD USING DIATOM METRICS

    Science.gov (United States)

    We compared the results of four methods used to assess the algal communities at 60 sites distributed among four rivers. Based on Principle Component Analysis of physical habitat data collected concomitantly with the algal data, sites were separated into those with a mean thalweg...

  14. Multiple histogram method and static Monte Carlo sampling

    NARCIS (Netherlands)

    Inda, M.A.; Frenkel, D.

    2004-01-01

    We describe an approach to use multiple-histogram methods in combination with static, biased Monte Carlo simulations. To illustrate this, we computed the force-extension curve of an athermal polymer from multiple histograms constructed in a series of static Rosenbluth Monte Carlo simulations. From

  15. Macroinvertebrate-based assessment of biological condition at selected sites in the Eagle River watershed, Colorado, 2000-07

    Science.gov (United States)

    Zuellig, Robert E.; Bruce, James F.; Healy, Brian D.; Williams, Cory A.

    2010-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, Colorado Springs Utilities, Denver Water, and the U.S. Department of Agriculture Forest Service (FS), compiled macroinvertebrate (73 sites, 124 samples) data previously collected in the Eagle River watershed from selected USGS and FS studies, 2000-07. These data were analyzed to assess the biological condition (that is, biologically ?degraded? or ?good?) at selected sites in the Eagle River watershed and determine if site class (for example, urban or undeveloped) described biological condition. An independently developed predictive model was applied to calculate a site-specific measure of taxonomic completeness for macroinvertebrate communities, where taxonomic completeness was expressed as the ratio of observed (O) taxa to those expected (E) to occur at each site. Macroinvertebrate communities were considered degraded at sites were O/E values were less than 0.80, indicating that at least 20 percent of expected taxa were not observed. Sites were classified into one of four classes (undeveloped, adjacent road or highway or both, mixed, urban) using a combination of riparian land-cover characteristics, examination of topographic maps and aerial imagery, screening for exceedances in water-quality standards, and best professional judgment. Analysis of variance was used to determine if site class accounted for variability in mean macroinvertebrate O/E values. Finally, macroinvertebrate taxa observed more or less frequently than expected at urban sites were indentified. This study represents the first standardized assessment of biological condition of selected sites distributed across the Eagle River watershed. Of the 73 sites evaluated, just over

  16. Sample preparation method for ICP-MS measurement of 99Tc in a large amount of environmental samples

    International Nuclear Information System (INIS)

    Kondo, M.; Seki, R.

    2002-01-01

    Sample preparation for measurement of 99 Tc in a large amount of soil and water samples by ICP-MS has been developed using 95m Tc as a yield tracer. This method is based on the conventional method for a small amount of soil samples using incineration, acid digestion, extraction chromatography (TEVA resin) and ICP-MS measurement. Preliminary concentration of Tc has been introduced by co-precipitation with ferric oxide. The matrix materials in a large amount of samples were more sufficiently removed with keeping the high recovery of Tc than previous method. The recovery of Tc was 70-80% for 100 g soil samples and 60-70% for 500 g of soil and 500 L of water samples. The detection limit of this method was evaluated as 0.054 mBq/kg in 500 g soil and 0.032 μBq/L in 500 L water. The determined value of 99 Tc in the IAEA-375 (soil sample collected near the Chernobyl Nuclear Reactor) was 0.25 ± 0.02 Bq/kg. (author)

  17. Solid phase microextraction headspace sampling of chemical warfare agent contaminated samples : method development for GC-MS analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jackson Lepage, C.R.; Hancock, J.R. [Defence Research and Development Canada, Medicine Hat, AB (Canada); Wyatt, H.D.M. [Regina Univ., SK (Canada)

    2004-07-01

    Defence R and D Canada-Suffield (DRDC-Suffield) is responsible for analyzing samples that are suspected to contain chemical warfare agents, either collected by the Canadian Forces or by first-responders in the event of a terrorist attack in Canada. The analytical techniques used to identify the composition of the samples include gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy. GC-MS and LC-MS generally require solvent extraction and reconcentration, thereby increasing sample handling. The authors examined analytical techniques which reduce or eliminate sample manipulation. In particular, this paper presented a screening method based on solid phase microextraction (SPME) headspace sampling and GC-MS analysis for chemical warfare agents such as mustard, sarin, soman, and cyclohexyl methylphosphonofluoridate in contaminated soil samples. SPME is a method which uses small adsorbent polymer coated silica fibers that trap vaporous or liquid analytes for GC or LC analysis. Collection efficiency can be increased by adjusting sampling time and temperature. This method was tested on two real-world samples, one from excavated chemical munitions and the second from a caustic decontamination mixture. 7 refs., 2 tabs., 3 figs.

  18. The study of combining Latin Hypercube Sampling method and LU decomposition method (LULHS method) for constructing spatial random field

    Science.gov (United States)

    WANG, P. T.

    2015-12-01

    Groundwater modeling requires to assign hydrogeological properties to every numerical grid. Due to the lack of detailed information and the inherent spatial heterogeneity, geological properties can be treated as random variables. Hydrogeological property is assumed to be a multivariate distribution with spatial correlations. By sampling random numbers from a given statistical distribution and assigning a value to each grid, a random field for modeling can be completed. Therefore, statistics sampling plays an important role in the efficiency of modeling procedure. Latin Hypercube Sampling (LHS) is a stratified random sampling procedure that provides an efficient way to sample variables from their multivariate distributions. This study combines the the stratified random procedure from LHS and the simulation by using LU decomposition to form LULHS. Both conditional and unconditional simulations of LULHS were develpoed. The simulation efficiency and spatial correlation of LULHS are compared to the other three different simulation methods. The results show that for the conditional simulation and unconditional simulation, LULHS method is more efficient in terms of computational effort. Less realizations are required to achieve the required statistical accuracy and spatial correlation.

  19. High-throughput liquid-absorption preconcentrator sampling methods

    Science.gov (United States)

    Zaromb, Solomon

    1994-01-01

    A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

  20. [DOE method for evaluating environmental and waste management samples: Revision 1, Addendum 1

    International Nuclear Information System (INIS)

    Goheen, S.C.

    1995-04-01

    The US Dapartment of Energy's (DOE's) environmental and waste management (EM) sampling and analysis activities require that large numbers of samples be analyzed for materials characterization, environmental surveillance, and site-remediation programs. The present document, DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), is a supplemental resource for analyzing many of these samples

  1. [DOE method for evaluating environmental and waste management samples: Revision 1, Addendum 1

    Energy Technology Data Exchange (ETDEWEB)

    Goheen, S.C.

    1995-04-01

    The US Dapartment of Energy`s (DOE`s) environmental and waste management (EM) sampling and analysis activities require that large numbers of samples be analyzed for materials characterization, environmental surveillance, and site-remediation programs. The present document, DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), is a supplemental resource for analyzing many of these samples.

  2. Detecting spatial structures in throughfall data: The effect of extent, sample size, sampling design, and variogram estimation method

    Science.gov (United States)

    Voss, Sebastian; Zimmermann, Beate; Zimmermann, Alexander

    2016-09-01

    In the last decades, an increasing number of studies analyzed spatial patterns in throughfall by means of variograms. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and a layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation method on variogram estimation of throughfall data. For our investigation, we first generated non-Gaussian random fields based on throughfall data with large outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling) and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments (non-robust and robust estimators) and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least 200 sampling points for reliable variogram estimates. These suggested sample sizes exceed the number recommended by studies dealing with Gaussian data by up to 100 %. Given that most previous

  3. Random sampling of quantum states: a survey of methods and some issues regarding the Overparametrized Method

    International Nuclear Information System (INIS)

    Maziero, Jonas

    2015-01-01

    The numerical generation of random quantum states (RQS) is an important procedure for investigations in quantum information science. Here, we review some methods that may be used for performing that task. We start by presenting a simple procedure for generating random state vectors, for which the main tool is the random sampling of unbiased discrete probability distributions (DPD). Afterwards, the creation of random density matrices is addressed. In this context, we first present the standard method, which consists in using the spectral decomposition of a quantum state for getting RQS from random DPDs and random unitary matrices. In the sequence, the Bloch vector parametrization method is described. This approach, despite being useful in several instances, is not in general convenient for RQS generation. In the last part of the article, we regard the overparametrized method (OPM) and the related Ginibre and Bures techniques. The OPM can be used to create random positive semidefinite matrices with unit trace from randomly produced general complex matrices in a simple way that is friendly for numerical implementations. We consider a physically relevant issue related to the possible domains that may be used for the real and imaginary parts of the elements of such general complex matrices. Subsequently, a too fast concentration of measure in the quantum state space that appears in this parametrization is noticed. (author)

  4. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  5. 7 CFR 51.308 - Methods of sampling and calculation of percentages.

    Science.gov (United States)

    2010-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Methods of Sampling and Calculation of Percentages § 51.308 Methods of sampling and calculation of percentages. (a) When the numerical... 7 Agriculture 2 2010-01-01 2010-01-01 false Methods of sampling and calculation of percentages. 51...

  6. THE STUDY OF WATER QUALITY USING BENTHIC MACROINVERTEBRATES AS BIOINDICATORS IN THE CATCHMENT AREAS OF THE RIVERS JIU, OLT AND IALOMIŢA

    Directory of Open Access Journals (Sweden)

    Elena Daniela MITITELU

    2012-01-01

    Full Text Available The wide distribution of benthic invertebrates and their different sensitivity shown upon modifying the qualitative parameters of aquatic ecosystems led to a frequent use of these group as bioindicators in different studies. The present study aims at presenting a list concerning the different macroinvertebrates identified in the larva stage in three watersheds (Jiu, Olt, Ialomiţa and establishing the water quality of the monitored sections using this benthic macroinvertebrates. The sample collecting points were represented by 23 stations. The abundance and frequency values recorded for benthic communities varied according to the physical-chemical conditions specific to each sample collecting station. There were identified 15 groups in total. The most frequent were Ephemeroptera, Plecoptera, Trichoptera, Diptera (Chironomidae and others. The deterioration of water quality is marked by the decrease in the biotic index EPT/Ch value.

  7. Effect of sample preparation methods on photometric determination of the tellurium and cobalt content in the samples of copper concentrates

    Directory of Open Access Journals (Sweden)

    Viktoriya Butenko

    2016-03-01

    Full Text Available Methods of determination of cobalt and nickel in copper concentrates currently used in factory laboratories are very labor intensive and time consuming. The limiting stage of the analysis is preliminary chemical sample preparation. Carrying out the decomposition process of industrial samples with concentrated mineral acids in open systems does not allow to improve the metrological characteristics of the methods, for this reason improvement the methods of sample preparation is quite relevant and has a practical interest. The work was dedicated to the determination of the optimal conditions of preliminary chemical preparation of copper concentrate samples for the subsequent determination of cobalt and tellurium in the obtained solution using tellurium-spectrophotometric method. Decomposition of the samples was carried out by acid dissolving in individual mineral acids and their mixtures by heating in an open system as well as by using ultrasonification and microwave radiation in a closed system. In order to select the optimal conditions for the decomposition of the samples in a closed system the phase contact time and ultrasonic generator’s power were varied. Intensification of the processes of decomposition of copper concentrates with nitric acid (1:1, ultrasound and microwave radiation allowed to transfer quantitatively cobalt and tellurium into solution spending 20 and 30 min respectively. This reduced the amount of reactants used and improved the accuracy of determination by running the process in strictly identical conditions.

  8. Sparsity-weighted outlier FLOODing (OFLOOD) method: Efficient rare event sampling method using sparsity of distribution.

    Science.gov (United States)

    Harada, Ryuhei; Nakamura, Tomotake; Shigeta, Yasuteru

    2016-03-30

    As an extension of the Outlier FLOODing (OFLOOD) method [Harada et al., J. Comput. Chem. 2015, 36, 763], the sparsity of the outliers defined by a hierarchical clustering algorithm, FlexDice, was considered to achieve an efficient conformational search as sparsity-weighted "OFLOOD." In OFLOOD, FlexDice detects areas of sparse distribution as outliers. The outliers are regarded as candidates that have high potential to promote conformational transitions and are employed as initial structures for conformational resampling by restarting molecular dynamics simulations. When detecting outliers, FlexDice defines a rank in the hierarchy for each outlier, which relates to sparsity in the distribution. In this study, we define a lower rank (first ranked), a medium rank (second ranked), and the highest rank (third ranked) outliers, respectively. For instance, the first-ranked outliers are located in a given conformational space away from the clusters (highly sparse distribution), whereas those with the third-ranked outliers are nearby the clusters (a moderately sparse distribution). To achieve the conformational search efficiently, resampling from the outliers with a given rank is performed. As demonstrations, this method was applied to several model systems: Alanine dipeptide, Met-enkephalin, Trp-cage, T4 lysozyme, and glutamine binding protein. In each demonstration, the present method successfully reproduced transitions among metastable states. In particular, the first-ranked OFLOOD highly accelerated the exploration of conformational space by expanding the edges. In contrast, the third-ranked OFLOOD reproduced local transitions among neighboring metastable states intensively. For quantitatively evaluations of sampled snapshots, free energy calculations were performed with a combination of umbrella samplings, providing rigorous landscapes of the biomolecules. © 2015 Wiley Periodicals, Inc.

  9. Macroinvertebrate fauna associated with Pistia stratiotes and Nymphoides indica in subtropical lakes (south Brazil

    Directory of Open Access Journals (Sweden)

    EF. Albertoni

    Full Text Available This study was carried out at the Biguás and Polegar lakes, both small environments but at different successional stages. The main objective was to characterize the macroinvertebrate community associated to the aquatic macrophyte stand in each lake in order for this community, the environmental conditions and their water quality to interact. The samples were taken in 2003. The abiotic variables of N and P totals, the temperature, electrical conductivity, pH and dissolved oxygen, as well as the determined clorophyll a concentration were measured. Macroinvertebrates were sampled with a 500 µ mesh size net, separated under a stereomicroscope and identified at the lowest possible taxonomic level, and their densities were shown as the number of individuals per 100 g of macrophyte dry weight. The Shannon-Wiener Diversity Index (H', Pielou evenness (J, frequency of occurrence, abundance and taxa richness were calculated for each invertebrate community. The Lago dos Biguás is undergoing a process of eutrophication and during the study presented a large Pistia stratiotes stand. The Lago Polegar is oligotrophic and had only a small Nymphoides indica bankwe. The macrophyte associated invertebrate communities in each lake were considered significantly different (p < 0.05. Sixty seven taxa were found for the Lago dos Biguás and 32 for the Lago Polegar. For both lakes, most of the taxa were considered rare, with a low dominance in a few months. The taxa with highest densities at Lago dos Biguás were Chironomidae, Daphniidae and Cyclopidae, and Oligochaeta, Chironomidae and Coenagrionidae for Lago Polegar.

  10. Comparing Microbiome Sampling Methods in a Wild Mammal: Fecal and Intestinal Samples Record Different Signals of Host Ecology, Evolution.

    Science.gov (United States)

    Ingala, Melissa R; Simmons, Nancy B; Wultsch, Claudia; Krampis, Konstantinos; Speer, Kelly A; Perkins, Susan L

    2018-01-01

    The gut microbiome is a community of host-associated symbiotic microbes that fulfills multiple key roles in host metabolism, immune function, and tissue development. Given the ability of the microbiome to impact host fitness, there is increasing interest in studying the microbiome of wild animals to better understand these communities in the context of host ecology and evolution. Human microbiome research protocols are well established, but wildlife microbiome research is still a developing field. Currently, there is no standardized set of best practices guiding the collection of microbiome samples from wildlife. Gut microflora are typically sampled either by fecal collection, rectal swabbing, or by destructively sampling the intestinal contents of the host animal. Studies rarely include more than one sampling technique and no comparison of these methods currently exists for a wild mammal. Although some studies have hypothesized that the fecal microbiome is a nested subset of the intestinal microbiome, this hypothesis has not been formally tested. To address these issues, we examined guano (feces) and distal intestinal mucosa from 19 species of free-ranging bats from Lamanai, Belize, using 16S rRNA amplicon sequencing to compare microbial communities across sample types. We found that the diversity and composition of intestine and guano samples differed substantially. In addition, we conclude that signatures of host evolution are retained by studying gut microbiomes based on mucosal tissue samples, but not fecal samples. Conversely, fecal samples retained more signal of host diet than intestinal samples. These results suggest that fecal and intestinal sampling methods are not interchangeable, and that these two microbiotas record different information about the host from which they are isolated.

  11. Comparing Microbiome Sampling Methods in a Wild Mammal: Fecal and Intestinal Samples Record Different Signals of Host Ecology, Evolution

    Directory of Open Access Journals (Sweden)

    Melissa R. Ingala

    2018-05-01

    Full Text Available The gut microbiome is a community of host-associated symbiotic microbes that fulfills multiple key roles in host metabolism, immune function, and tissue development. Given the ability of the microbiome to impact host fitness, there is increasing interest in studying the microbiome of wild animals to better understand these communities in the context of host ecology and evolution. Human microbiome research protocols are well established, but wildlife microbiome research is still a developing field. Currently, there is no standardized set of best practices guiding the collection of microbiome samples from wildlife. Gut microflora are typically sampled either by fecal collection, rectal swabbing, or by destructively sampling the intestinal contents of the host animal. Studies rarely include more than one sampling technique and no comparison of these methods currently exists for a wild mammal. Although some studies have hypothesized that the fecal microbiome is a nested subset of the intestinal microbiome, this hypothesis has not been formally tested. To address these issues, we examined guano (feces and distal intestinal mucosa from 19 species of free-ranging bats from Lamanai, Belize, using 16S rRNA amplicon sequencing to compare microbial communities across sample types. We found that the diversity and composition of intestine and guano samples differed substantially. In addition, we conclude that signatures of host evolution are retained by studying gut microbiomes based on mucosal tissue samples, but not fecal samples. Conversely, fecal samples retained more signal of host diet than intestinal samples. These results suggest that fecal and intestinal sampling methods are not interchangeable, and that these two microbiotas record different information about the host from which they are isolated.

  12. Diversity, composition and abundance of macroinvertebrates ...

    African Journals Online (AJOL)

    user

    these genera were found at all sampling stations as shown in Table 2. Out of the orders sampled, Hemiptera, Pulmonata and. Coleoptera had the highest number of genera with 5, 4 and 4, respectively. In terms of relative abundance, dipterans and Pulmonata were the most abundant while. Hydracarina (water mites) were ...

  13. Perilymph sampling from the cochlear apex: a reliable method to obtain higher purity perilymph samples from scala tympani.

    Science.gov (United States)

    Salt, Alec N; Hale, Shane A; Plonkte, Stefan K R

    2006-05-15

    Measurements of drug levels in the fluids of the inner ear are required to establish kinetic parameters and to determine the influence of specific local delivery protocols. For most substances, this requires cochlear fluids samples to be obtained for analysis. When auditory function is of primary interest, the drug level in the perilymph of scala tympani (ST) is most relevant, since drug in this scala has ready access to the auditory sensory cells. In many prior studies, ST perilymph samples have been obtained from the basal turn, either by aspiration through the round window membrane (RWM) or through an opening in the bony wall. A number of studies have demonstrated that such samples are likely to be contaminated with cerebrospinal fluid (CSF). CSF enters the basal turn of ST through the cochlear aqueduct when the bony capsule is perforated or when fluid is aspirated. The degree of sample contamination has, however, not been widely appreciated. Recent studies have shown that perilymph samples taken through the round window membrane are highly contaminated with CSF, with samples greater than 2microL in volume containing more CSF than perilymph. In spite of this knowledge, many groups continue to sample from the base of the cochlea, as it is a well-established method. We have developed an alternative, technically simple method to increase the proportion of ST perilymph in a fluid sample. The sample is taken from the apex of the cochlea, a site that is distant from the cochlear aqueduct. A previous problem with sampling through a perforation in the bone was that the native perilymph rapidly leaked out driven by CSF pressure and was lost to the middle ear space. We therefore developed a procedure to collect all the fluid that emerged from the perforated apex after perforation. We evaluated the method using a marker ion trimethylphenylammonium (TMPA). TMPA was applied to the perilymph of guinea pigs either by RW irrigation or by microinjection into the apical turn. The

  14. Stream biomonitoring using macroinvertebrates around the globe

    NARCIS (Netherlands)

    Buss, Daniel F.; Carlisle, Daren M.; Chon, Tae Soo; Culp, Joseph; Harding, Jon S.; Keizer-Vlek, H.E.; Robinson, Wayne A.; Strachan, Stephanie; Thirion, Christa; Hughes, Robert M.

    2015-01-01

    Water quality agencies and scientists are increasingly adopting standardized sampling methodologies because of the challenges associated with interpreting data derived from dissimilar protocols. Here, we compare 13 protocols for monitoring streams from different regions and countries around the

  15. Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality

    Science.gov (United States)

    Sefa, Eunice; Adimazoya, Edward Akolgo; Yartey, Emmanuel; Lenzi, Rachel; Tarpo, Cindy; Heward-Mills, Nii Lante; Lew, Katherine; Ampeh, Yvonne

    2018-01-01

    Introduction Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample. Materials and methods The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census. Results The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample. Conclusions The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in

  16. Surveying immigrants without sampling frames - evaluating the success of alternative field methods.

    Science.gov (United States)

    Reichel, David; Morales, Laura

    2017-01-01

    This paper evaluates the sampling methods of an international survey, the Immigrant Citizens Survey, which aimed at surveying immigrants from outside the European Union (EU) in 15 cities in seven EU countries. In five countries, no sample frame was available for the target population. Consequently, alternative ways to obtain a representative sample had to be found. In three countries 'location sampling' was employed, while in two countries traditional methods were used with adaptations to reach the target population. The paper assesses the main methodological challenges of carrying out a survey among a group of immigrants for whom no sampling frame exists. The samples of the survey in these five countries are compared to results of official statistics in order to assess the accuracy of the samples obtained through the different sampling methods. It can be shown that alternative sampling methods can provide meaningful results in terms of core demographic characteristics although some estimates differ to some extent from the census results.

  17. The influence of urbanisation on macroinvertebrate biodiversity in constructed stormwater wetlands.

    Science.gov (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M

    2015-12-01

    The construction of wetlands in urban environments is primarily carried out to assist in the removal of contaminants from wastewaters; however, these wetlands have the added benefit of providing habitat for aquatic invertebrates, fish and waterbirds. Stormwater quantity and quality is directly related to impervious area (roads, sealed areas, roofs) in the catchment. As a consequence, it would be expected that impervious area would be related to contaminant load and biodiversity in receiving waters such as urban wetlands. This study aimed to establish whether the degree of urbanisation and its associated changes to stormwater runoff affected macroinvertebrate richness and abundance within constructed wetlands. Urban wetlands in Melbourne's west and south east were sampled along a gradient of urbanisation. There was a significant negative relationship between total imperviousness (TI) and the abundance of aquatic invertebrates detected for sites in the west, but not in the south east. However macroinvertebrate communities were relatively homogenous both within and between all study wetlands. Chironomidae (non-biting midges) was the most abundant family recorded at the majority of sites. Chironomids are able to tolerate a wide array of environmental conditions, including eutrophic and anoxic conditions. Their prevalence suggests that water quality is impaired in these systems, regardless of degree of urbanisation, although the causal mechanism is unclear. These results show some dependency between receiving wetland condition and the degree of urbanisation of the catchment, but suggest that other factors may be as important in determining the value of urban wetlands as habitat for wildlife. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Effects of extreme floods on macroinvertebrate assemblages in tributaries to the Mohawk River, New York, USA

    Science.gov (United States)

    Calderon, Mirian R.; Baldigo, Barry P.; Smith, Alexander J.; Endreny, Theodore A.

    2017-01-01

    Climate change is forecast to bring more frequent and intense precipitation to New York which has motivated research into the effects of floods on stream ecosystems. Macroinvertebrate assemblages were sampled at 13 sites in the Mohawk River basin during August 2011, and again in October 2011, following historic floods caused by remnants of Hurricane Irene and Tropical Storm Lee. The annual exceedance probabilities of floods at regional flow-monitoring sites ranged from 0.5 to 0.001. Data from the first 2 surveys, and from additional surveys done during July and October 2014, were assessed to characterize the severity of flood impacts, effect of seasonality, and recovery. Indices of total taxa richness; Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness; Hilsenhoff's biotic index; per cent model affinity; and nutrient biotic index-phosphorus were combined to calculate New York State Biological Assessment Profile scores. Analysis of variance tests were used to determine if the Biological Assessment Profile, its component metrics, relative abundance, and diversity differed significantly (p ≤ .05) among the four surveys. Only total taxa richness and Shannon–Wiener diversity increased significantly, and abundance decreased significantly, following the floods. No metrics differed significantly between the July and August 2014 surveys which indicates that the differences denoted between the August and October 2011 surveys were caused by the floods. Changes in taxa richness, EPT richness, and diversity were significantly correlated with flood annual exceedance probabilities. This study increased our understanding of the resistance and resilience of benthic macroinvertebrate communities by showing that their assemblages were relatively impervious to extreme floods across the region.

  19. Abundance and distribution of benthic macroinvertebrates in offshore soft sediments in Western Lake Huron, 2001-2007

    Science.gov (United States)

    French, J. R. P.; Schaeffer, J.S.; Roseman, E.F.; Kiley, C.S.; Fouilleroux, A.

    2009-01-01

    Invasive species have had major impacts on the Great Lakes. This is especially true of exotic dreissenid mussels which are associated with decreased abundance of native macroinvertebrates and changes in food availability for fish. Beginning in 2001, we added a benthic macroinvertebrate survey to the USGS-Great Lakes Science Center's annual fall prey fish assessment of Lake Huron to monitor abundance of macrobenthos. Mean abundance of Diporeia, the most abundant benthic taxon in Lake Huron reported by previous investigators, declined greatly between 2001 and 2007. Diporeia was virtually absent at 27-m sites by 2001, decreased and was lost completely from 46-m depths by 2006, but remained present at reduced densities at 73-m sites. Dreissenids in our samples were almost entirely quagga mussels Dreissena bugensis. Zebra mussels Dreissena polymorpha were virtually absent from our samples, suggesting that they were confined to nearshore areas shallower than we sampled. Loss of Diporeia at individual sites was associated with arrival of quagga mussels, even when mussel densities were low. Quagga mussel density peaked during 2002, then decreased thereafter. During the study quagga mussels became established at most 46-m sites, but remained rare at 73-m sites. Length frequency distributions suggest that initial widespread recruitment may have occurred during 2001-2002. Like other Great Lakes, Lake Huron quagga mussels were associated with decreased abundance of native taxa, but negative effects occurred even though dreissenid densities were much lower. Dreissenid effects may extend well into deep oligotrophic habitats of Lake Huron.

  20. A Sequential Optimization Sampling Method for Metamodels with Radial Basis Functions

    Science.gov (United States)

    Pan, Guang; Ye, Pengcheng; Yang, Zhidong

    2014-01-01

    Metamodels have been widely used in engineering design to facilitate analysis and optimization of complex systems that involve computationally expensive simulation programs. The accuracy of metamodels is strongly affected by the sampling methods. In this paper, a new sequential optimization sampling method is proposed. Based on the new sampling method, metamodels can be constructed repeatedly through the addition of sampling points, namely, extrema points of metamodels and minimum points of density function. Afterwards, the more accurate metamodels would be constructed by the procedure above. The validity and effectiveness of proposed sampling method are examined by studying typical numerical examples. PMID:25133206

  1. Sampling methods. A survey of methods in use in the Nordic countries

    International Nuclear Information System (INIS)

    Isaksson, M.

    2000-10-01

    This report is a survey of sampling techniques currently in use for radioactivity measurements in the Nordic countries, but restricted to sampling techniques for pasture, soil and deposition in emergency situations. It is found that the participating laboratories apply similar sampling procedures for pasture, including cutting height and size of sampled areas. Soil samples are generally taken by some sort of corer of different diameter. The number of cores taken varies, different sampling patterns are used, and pooling of the samples is done by some of the laboratories. The analysis of pasture and of soil is made with Nal-detectors or by high-resolution gamma spectrometry on fresh or dried samples. Precipitation collectors of a range of sizes are used to determine the activity concentration in precipitation and of dry deposited radionuclides. The analysis is made with high-resolution gamma-spectrometry, either directly on a water sample or on ion exchange resins. (au)

  2. SnagPRO: snag and tree sampling and analysis methods for wildlife

    Science.gov (United States)

    Lisa J. Bate; Michael J. Wisdom; Edward O. Garton; Shawn C. Clabough

    2008-01-01

    We describe sampling methods and provide software to accurately and efficiently estimate snag and tree densities at desired scales to meet a variety of research and management objectives. The methods optimize sampling effort by choosing a plot size appropriate for the specified forest conditions and sampling goals. Plot selection and data analyses are supported by...

  3. Evaluation of benthic macroinvertebrate assemblage for disturbance ...

    Indian Academy of Sciences (India)

    The Ganga River System Biotic Score (GRSbios) index was applied to determine the ecological ... plemented and today the organic river pollution is gradually ... ing the chemical status of all the surface water in Europe .... 2.2 Sampling sites and approach. In total ...... an Integration of Engineering, Design and Management.

  4. Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality.

    Science.gov (United States)

    L'Engle, Kelly; Sefa, Eunice; Adimazoya, Edward Akolgo; Yartey, Emmanuel; Lenzi, Rachel; Tarpo, Cindy; Heward-Mills, Nii Lante; Lew, Katherine; Ampeh, Yvonne

    2018-01-01

    Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample. The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census. The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample. The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in comparison to household surveys. Random digit dialing of mobile

  5. Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality.

    Directory of Open Access Journals (Sweden)

    Kelly L'Engle

    Full Text Available Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample.The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census.The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample.The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in comparison to household surveys. Random digit

  6. 222Rn in water: A comparison of two sample collection methods and two sample transport methods, and the determination of temporal variation in North Carolina ground water

    International Nuclear Information System (INIS)

    Hightower, J.H. III

    1994-01-01

    Objectives of this field experiment were: (1) determine whether there was a statistically significant difference between the radon concentrations of samples collected by EPA's standard method, using a syringe, and an alternative, slow-flow method; (2) determine whether there was a statistically significant difference between the measured radon concentrations of samples mailed vs samples not mailed; and (3) determine whether there was a temporal variation of water radon concentration over a 7-month period. The field experiment was conducted at 9 sites, 5 private wells, and 4 public wells, at various locations in North Carolina. Results showed that a syringe is not necessary for sample collection, there was generally no significant radon loss due to mailing samples, and there was statistically significant evidence of temporal variations in water radon concentrations

  7. Influences of different sample preparation methods on tooth enamel ESR signals

    International Nuclear Information System (INIS)

    Zhang Wenyi; Jiao Ling; Zhang Liang'an; Pan Zhihong; Zeng Hongyu

    2005-01-01

    Objective: To study the influences of different sample preparation methods on tooth enamel ESR signals in order to reduce the effect of dentine on their sensitivities to radiation. Methods: The enamel was separated from dentine of non-irradiated adult teeth by mechanical, chemical, or both methods. The samples of different preparations were scanned by an ESR spectrometer before and after irradiation. Results: The response of ESR signals of samples prepared with different methods to radiation dose was significantly different. Conclusion: The selection of sample preparation method is very important for dose reconstruction by tooth enamel ESR dosimetry, especially in the low dose range. (authors)

  8. Enhanced Sampling in Free Energy Calculations: Combining SGLD with the Bennett's Acceptance Ratio and Enveloping Distribution Sampling Methods.

    Science.gov (United States)

    König, Gerhard; Miller, Benjamin T; Boresch, Stefan; Wu, Xiongwu; Brooks, Bernard R

    2012-10-09

    One of the key requirements for the accurate calculation of free energy differences is proper sampling of conformational space. Especially in biological applications, molecular dynamics simulations are often confronted with rugged energy surfaces and high energy barriers, leading to insufficient sampling and, in turn, poor convergence of the free energy results. In this work, we address this problem by employing enhanced sampling methods. We explore the possibility of using self-guided Langevin dynamics (SGLD) to speed up the exploration process in free energy simulations. To obtain improved free energy differences from such simulations, it is necessary to account for the effects of the bias due to the guiding forces. We demonstrate how this can be accomplished for the Bennett's acceptance ratio (BAR) and the enveloping distribution sampling (EDS) methods. While BAR is considered among the most efficient methods available for free energy calculations, the EDS method developed by Christ and van Gunsteren is a promising development that reduces the computational costs of free energy calculations by simulating a single reference state. To evaluate the accuracy of both approaches in connection with enhanced sampling, EDS was implemented in CHARMM. For testing, we employ benchmark systems with analytical reference results and the mutation of alanine to serine. We find that SGLD with reweighting can provide accurate results for BAR and EDS where conventional molecular dynamics simulations fail. In addition, we compare the performance of EDS with other free energy methods. We briefly discuss the implications of our results and provide practical guidelines for conducting free energy simulations with SGLD.

  9. A DOE manual: DOE Methods for Evaluating Environmental and Waste Management Samples

    International Nuclear Information System (INIS)

    Goheen, S.C.; McCulloch, M.; Riley, R.G.

    1994-01-01

    Waste Management inherently requires knowledge of the waste's chemical composition. The waste can often be analyzed by established methods; however, if the samples are radioactive, or are plagued by other complications, established methods may not be feasible. The US Department of Energy (DOE) has been faced with managing some waste types that are not amenable to standard or available methods, so new or modified sampling and analysis methods are required. These methods are incorporated into DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), which is a guidance/methods document for sampling and analysis activities in support of DOE sites. It is a document generated by consensus of the DOE laboratory staff and is intended to fill the gap within existing guidance documents (e. g., the Environmental Protection Agency's (EPA's) Test Methods for Evaluating Solid Waste, SW-846), which apply to low-level or non-radioactive samples. DOE Methods fills the gap by including methods that take into account the complexities of DOE site matrices. The most recent update, distributed in October 1993, contained quality assurance (QA), quality control (QC), safety, sampling, organic analysis, inorganic analysis, and radioanalytical guidance as well as 29 methods. The next update, which will be distributed in April 1994, will contain 40 methods and will therefore have greater applicability. All new methods are either peer reviewed or labeled ''draft'' methods. Draft methods were added to speed the release of methods to field personnel

  10. Combined effects of water stress and pollution on macroinvertebrate and fish assemblages in a Mediterranean intermittent river.

    Science.gov (United States)

    Kalogianni, Eleni; Vourka, Aikaterini; Karaouzas, Ioannis; Vardakas, Leonidas; Laschou, Sofia; Skoulikidis, Nikolaos Th

    2017-12-15

    Water stress is a key stressor in Mediterranean intermittent rivers exacerbating the negative effects of other stressors, such as pollutants, with multiple effects on different river biota. The current study aimed to determine the response of macroinvertebrate and fish assemblages to instream habitat and water chemistry, at the microhabitat scale and at different levels of water stress and pollution, in an intermittent Mediterranean river. Sampling was conducted at high and low summer discharge, at two consecutive years, and included four reaches that were targeted for their different levels of water stress and pollution. Overall, the macroinvertebrate fauna of Evrotas River indicated high resilience to intermittency, however, variation in community structure and composition occurred under acute water stress, due to habitat alteration and change in water physico-chemistry, i.e. water temperature increase. The combined effects of pollution and high water stress had, however, pronounced effects on species richness, abundance and community structure in the pollution impacted reach, where pollution sensitive taxa were almost extirpated. Fish response to drought, in reaches free of pollution, consisted of an increase in the abundance of the two small limnophilic species, coupled with their shift to faster flowing riffle habitats, and a reduction in the abundance of the larger, rheophilic species. In the pollution impacted reach, however, the combination of pollution and high water stress led to hypoxic conditions assumed to be the leading cause of the almost complete elimination of the fish assemblage. In contrast, the perennial Evrotas reaches with relatively stable physicochemical conditions, though affected hydrologically by drought, appear to function as refugia for fish during high water stress. When comparing the response of the two biotic groups to combined acute water stress and pollution, it is evident that macroinvertebrates were negatively impacted, but fish

  11. A Convenient Method for Estimation of the Isotopic Abundance in Uranium Bearing Samples

    International Nuclear Information System (INIS)

    AI -Saleh, F.S.; AI-Mukren, Alj.H.; Farouk, M.A.

    2008-01-01

    A convenient and simple method for estimation of the isotopic abundance in some uranium bearing samples using gamma-ray spectrometry is developed using a hyper pure germanium spectrometer and a standard uranium sample with known isotopic abundance

  12. A study of post-thermal recovery of the macroinvertebrate community of Four Mile Creek, June 1985--September 1987. [Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Lauritsen, D.; Starkel, W.; Specht, W.

    1989-11-01

    Four Mile Creek is one of several streams at the Savannah River Site which has received thermal effluents ({le}70{degrees}C water) from nuclear production operations. From 1955--mid-1985, Four Mile Creek received thermal effluent from C-Reactor as well as non-thermal discharges from F and H Separation Areas. Total discharges from all of these facilities was about ten times higher than the natural flow of the creek (Firth et al. 1986). All water being discharged into Four Mile Creek was originally pumped from the Savannah River. This study reports the results of the artificial substrate sampling of macroinvertebrate communities of Four Mile Creek from June 1985 through September 1987, when sampling was terminated. Macroinvertebrate taxa richness, densities, and biomass data from this study are compared to Four Mile data collected prior to the shutdown of C-Reactor (Kondratieff and Kondratieff 1985 and Firth et al. 1986), and to comparable macroinvertebrate data from other Savannah River Site streams. 29 refs., 11 figs., 4 tabs.

  13. Comparing Respondent-Driven Sampling and Targeted Sampling Methods of Recruiting Injection Drug Users in San Francisco

    Science.gov (United States)

    Malekinejad, Mohsen; Vaudrey, Jason; Martinez, Alexis N.; Lorvick, Jennifer; McFarland, Willi; Raymond, H. Fisher

    2010-01-01

    The objective of this article is to compare demographic characteristics, risk behaviors, and service utilization among injection drug users (IDUs) recruited from two separate studies in San Francisco in 2005, one which used targeted sampling (TS) and the other which used respondent-driven sampling (RDS). IDUs were recruited using TS (n = 651) and RDS (n = 534) and participated in quantitative interviews that included demographic characteristics, risk behaviors, and service utilization. Prevalence estimates and 95% confidence intervals (CIs) were calculated to assess whether there were differences in these variables by sampling method. There was overlap in 95% CIs for all demographic variables except African American race (TS: 45%, 53%; RDS: 29%, 44%). Maps showed that the proportion of IDUs distributed across zip codes were similar for the TS and RDS sample, with the exception of a single zip code that was more represented in the TS sample. This zip code includes an isolated, predominantly African American neighborhood where only the TS study had a field site. Risk behavior estimates were similar for both TS and RDS samples, although self-reported hepatitis C infection was lower in the RDS sample. In terms of service utilization, more IDUs in the RDS sample reported no recent use of drug treatment and syringe exchange program services. Our study suggests that perhaps a hybrid sampling plan is best suited for recruiting IDUs in San Francisco, whereby the more intensive ethnographic and secondary analysis components of TS would aid in the planning of seed placement and field locations for RDS. PMID:20582573

  14. Detection and monitoring of invasive exotic plants: a comparison of four sampling methods

    Science.gov (United States)

    Cynthia D. Huebner

    2007-01-01

    The ability to detect and monitor exotic invasive plants is likely to vary depending on the sampling method employed. Methods with strong qualitative thoroughness for species detection often lack the intensity necessary to monitor vegetation change. Four sampling methods (systematic plot, stratified-random plot, modified Whittaker, and timed meander) in hemlock and red...

  15. Effects of streambank fencing of pasture land on benthic macroinvertebrates and the quality of surface water and shallow ground water in the Big Spring Run basin of Mill Creek watershed, Lancaster County, Pennsylvania, 1993-2001

    Science.gov (United States)

    Galeone, Daniel G.; Brightbill, Robin A.; Low, Dennis J.; O'Brien, David L.

    2006-01-01

    were collected in May and September of each year; samples were collected at the outlet of the control and treatment basins and at three upstream sites, two in the treatment basin and one in the control basin. For each benthic-macroinvertebrate sample: Stream riffles and pools were sampled using the kick-net method; habitat was characterized using Rapid Bioassessment Protocols (RBP); water-quality samples were collected for nutrients and suspended sediment; stream field parameters were measured; and multiple biological metrics were calculated. The experimental design to study the effects of fencing on the quality of near-stream shallow ground water involved a nested well approach. Two well nests were in the treatment basin, one each at surface-water sites T-1 and T-2. Within each well nest, the data from one deep well and three shallow wells (no greater than 12 ft deep) were used for regional characterization of ground-water quality. At each site, two of the shallow wells were inside the eventual fence (treated wells); the other shallow well was outside the eventual fence (control well). The wells were sampled monthly, primarily during periods with little to no recharge, for laboratory analysis of nutrients and fecal streptococcus; field parameters of water quality also were measured.

  16. Comparison of four sampling methods for the detection of Salmonella in broiler litter.

    Science.gov (United States)

    Buhr, R J; Richardson, L J; Cason, J A; Cox, N A; Fairchild, B D

    2007-01-01

    Experiments were conducted to compare litter sampling methods for the detection of Salmonella. In experiment 1, chicks were challenged orally with a suspension of naladixic acid-resistant Salmonella and wing banded, and additional nonchallenged chicks were placed into each of 2 challenge pens. Nonchallenged chicks were placed into each nonchallenge pen located adjacent to the challenge pens. At 7, 8, 10, and 11 wk of age the litter was sampled using 4 methods: fecal droppings, litter grab, drag swab, and sock. For the challenge pens, Salmonella-positive samples were detected in 3 of 16 fecal samples, 6 of 16 litter grab samples, 7 of 16 drag swabs samples, and 7 of 16 sock samples. Samples from the nonchallenge pens were Salmonella positive in 2 of 16 litter grab samples, 9 of 16 drag swab samples, and 9 of 16 sock samples. In experiment 2, chicks were challenged with Salmonella, and the litter in the challenge and adjacent nonchallenge pens were sampled at 4, 6, and 8 wk of age with broilers remaining in all pens. For the challenge pens, Salmonella was detected in 10 of 36 fecal samples, 20 of 36 litter grab samples, 14 of 36 drag swab samples, and 26 of 36 sock samples. Samples from the adjacent nonchallenge pens were positive for Salmonella in 6 of 36 fecal droppings samples, 4 of 36 litter grab samples, 7 of 36 drag swab samples, and 19 of 36 sock samples. Sock samples had the highest rates of Salmonella detection. In experiment 3, the litter from a Salmonella-challenged flock was sampled at 7, 8, and 9 wk by socks and drag swabs. In addition, comparisons with drag swabs that were stepped on during sampling were made. Both socks (24 of 36, 67%) and drag swabs that were stepped on (25 of 36, 69%) showed significantly more Salmonella-positive samples than the traditional drag swab method (16 of 36, 44%). Drag swabs that were stepped on had comparable Salmonella detection level to that for socks. Litter sampling methods that incorporate stepping on the sample

  17. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates

    International Nuclear Information System (INIS)

    Bryer, Pamela J.; Scoggins, Mateo; McClintock, Nancy L.

    2010-01-01

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, and 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments. - Coal-tar pavement sealants degrade stream invertebrate communities.

  18. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates.

    Science.gov (United States)

    Bryer, Pamela J; Scoggins, Mateo; McClintock, Nancy L

    2010-05-01

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, & 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P pavement sealants contain bioavailable PAHs that may harm aquatic environments. Copyright 2009 Elsevier Ltd. All rights reserved.

  19. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Bryer, P.J.; Scoggins, M.; McClintock, N.L. [Lamar University, Beaumont, TX (United States). Dept. of Biology

    2010-05-15

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, & 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments.

  20. Patterns of Macroinvertebrate and Fish Diversity in Freshwater Sulphide Springs

    Directory of Open Access Journals (Sweden)

    Ryan Greenway

    2014-09-01

    Full Text Available Extreme environments are characterised by the presence of physicochemical stressors and provide unique study systems to address problems in evolutionary ecology research. Sulphide springs provide an example of extreme freshwater environments; because hydrogen sulphide’s adverse physiological effects induce mortality in metazoans even at micromolar concentrations. Sulphide springs occur worldwide, but while microbial communities in sulphide springs have received broad attention, little is known about macroinvertebrates and fish inhabiting these toxic environments. We reviewed qualitative occurrence records of sulphide spring faunas on a global scale and present a quantitative case study comparing diversity patterns in sulphidic and adjacent non-sulphidic habitats across replicated river drainages in Southern Mexico. While detailed studies in most regions of the world remain scarce, available data suggests that sulphide spring faunas are characterised by low species richness. Dipterans (among macroinvertebrates and cyprinodontiforms (among fishes appear to dominate the communities in these habitats. At least in fish, there is evidence for the presence of highly endemic species and populations exclusively inhabiting sulphide springs. We provide a detailed discussion of traits that might predispose certain taxonomic groups to colonize sulphide springs, how colonizers subsequently adapt to cope with sulphide toxicity, and how adaptation may be linked to speciation processes.

  1. Stream habitat structure influences macroinvertebrate response to pesticides

    International Nuclear Information System (INIS)

    Rasmussen, Jes Jessen; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette; Friberg, Nikolai; Kronvang, Brian

    2012-01-01

    Agricultural pesticides continue to impair surface water ecosystems, although there are few assessments of interactions with other modifications such as fine sediment and physical alteration for flood drainage. We, therefore, surveyed pesticide contamination and macroinvertebrates in 14 streams along a gradient of expected pesticide exposure using a paired-reach approach to differentiate effects between physically modified and less modified sites. Apparent pesticides effects on the relative abundance of SPEcies At Risk (SPEAR) were increased at sites with degraded habitats primarily due to the absence of species with specific preferences for hard substrates. Our findings highlight the importance of physical habitat degradation in the assessment and mitigation of pesticide risk in agricultural streams. - Highlights: ► %SPEAR abundance significantly decreased with increasing TU (D. magna). ► %SPEAR abundance was significantly lower when soft sediment was dominant. ► Species specific habitat preferences influenced the total effect of pesticides. ► This study has strong implications for future stream management and risk assessment. - Ecological impacts of pesticides on stream macroinvertebrates are influenced by the heterogeneity and physical structure of micro-habitats.

  2. Comparability of river suspended-sediment sampling and laboratory analysis methods

    Science.gov (United States)

    Groten, Joel T.; Johnson, Gregory D.

    2018-03-06

    Accurate measurements of suspended sediment, a leading water-quality impairment in many Minnesota rivers, are important for managing and protecting water resources; however, water-quality standards for suspended sediment in Minnesota are based on grab field sampling and total suspended solids (TSS) laboratory analysis methods that have underrepresented concentrations of suspended sediment in rivers compared to U.S. Geological Survey equal-width-increment or equal-discharge-increment (EWDI) field sampling and suspended sediment concentration (SSC) laboratory analysis methods. Because of this underrepresentation, the U.S. Geological Survey, in collaboration with the Minnesota Pollution Control Agency, collected concurrent grab and EWDI samples at eight sites to compare results obtained using different combinations of field sampling and laboratory analysis methods.Study results determined that grab field sampling and TSS laboratory analysis results were biased substantially low compared to EWDI sampling and SSC laboratory analysis results, respectively. Differences in both field sampling and laboratory analysis methods caused grab and TSS methods to be biased substantially low. The difference in laboratory analysis methods was slightly greater than field sampling methods.Sand-sized particles had a strong effect on the comparability of the field sampling and laboratory analysis methods. These results indicated that grab field sampling and TSS laboratory analysis methods fail to capture most of the sand being transported by the stream. The results indicate there is less of a difference among samples collected with grab field sampling and analyzed for TSS and concentration of fines in SSC. Even though differences are present, the presence of strong correlations between SSC and TSS concentrations provides the opportunity to develop site specific relations to address transport processes not captured by grab field sampling and TSS laboratory analysis methods.

  3. Small-scale habitat structure modulates the effects of no-take marine reserves for coral reef macroinvertebrates.

    Directory of Open Access Journals (Sweden)

    Pascal Dumas

    Full Text Available No-take marine reserves are one of the oldest and most versatile tools used across the Pacific for the conservation of reef resources, in particular for invertebrates traditionally targeted by local fishers. Assessing their actual efficiency is still a challenge in complex ecosystems such as coral reefs, where reserve effects are likely to be obscured by high levels of environmental variability. The goal of this study was to investigate the potential interference of small-scale habitat structure on the efficiency of reserves. The spatial distribution of widely harvested macroinvertebrates was surveyed in a large set of protected vs. unprotected stations from eleven reefs located in New Caledonia. Abundance, density and individual size data were collected along random, small-scale (20×1 m transects. Fine habitat typology was derived with a quantitative photographic method using 17 local habitat variables. Marine reserves substantially augmented the local density, size structure and biomass of the target species. Density of Trochus niloticus and Tridacna maxima doubled globally inside the reserve network; average size was greater by 10 to 20% for T. niloticus. We demonstrated that the apparent success of protection could be obscured by marked variations in population structure occurring over short distances, resulting from small-scale heterogeneity in the reef habitat. The efficiency of reserves appeared to be modulated by the availability of suitable habitats at the decimetric scale ("microhabitats" for the considered sessile/low-mobile macroinvertebrate species. Incorporating microhabitat distribution could significantly enhance the efficiency of habitat surrogacy, a valuable approach in the case of conservation targets focusing on endangered or emblematic macroinvertebrate or relatively sedentary fish species.

  4. Individual and pen-based oral fluid sampling: A welfare-friendly sampling method for group-housed gestating sows.

    Science.gov (United States)

    Pol, Françoise; Dorenlor, Virginie; Eono, Florent; Eudier, Solveig; Eveno, Eric; Liégard-Vanhecke, Dorine; Rose, Nicolas; Fablet, Christelle

    2017-11-01

    The aims of this study were to assess the feasibility of individual and pen-based oral fluid sampling (OFS) in 35 pig herds with group-housed sows, compare these methods to blood sampling, and assess the factors influencing the success of sampling. Individual samples were collected from at least 30 sows per herd. Pen-based OFS was performed using devices placed in at least three pens for 45min. Information related to the farm, the sows, and their living conditions were collected. Factors significantly associated with the duration of sampling and the chewing behaviour of sows were identified by logistic regression. Individual OFS took 2min 42s on average; the type of floor, swab size, and operator were associated with a sampling time >2min. Pen-based OFS was obtained from 112 devices (62.2%). The type of floor, parity, pen-level activity, and type of feeding were associated with chewing behaviour. Pen activity was associated with the latency to interact with the device. The type of floor, gestation stage, parity, group size, and latency to interact with the device were associated with a chewing time >10min. After 15, 30 and 45min of pen-based OFS, 48%, 60% and 65% of the sows were lying down, respectively. The time spent after the beginning of sampling, genetic type, and time elapsed since the last meal were associated with 50% of the sows lying down at one time point. The mean time to blood sample the sows was 1min 16s and 2min 52s if the number of operators required was considered in the sampling time estimation. The genetic type, parity, and type of floor were significantly associated with a sampling time higher than 1min 30s. This study shows that individual OFS is easy to perform in group-housed sows by a single operator, even though straw-bedded animals take longer to sample than animals housed on slatted floors, and suggests some guidelines to optimise pen-based OFS success. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Sampling designs and methods for estimating fish-impingement losses at cooling-water intakes

    International Nuclear Information System (INIS)

    Murarka, I.P.; Bodeau, D.J.

    1977-01-01

    Several systems for estimating fish impingement at power plant cooling-water intakes are compared to determine the most statistically efficient sampling designs and methods. Compared to a simple random sampling scheme the stratified systematic random sampling scheme, the systematic random sampling scheme, and the stratified random sampling scheme yield higher efficiencies and better estimators for the parameters in two models of fish impingement as a time-series process. Mathematical results and illustrative examples of the applications of the sampling schemes to simulated and real data are given. Some sampling designs applicable to fish-impingement studies are presented in appendixes

  6. Simulated Tempering Distributed Replica Sampling, Virtual Replica Exchange, and Other Generalized-Ensemble Methods for Conformational Sampling.

    Science.gov (United States)

    Rauscher, Sarah; Neale, Chris; Pomès, Régis

    2009-10-13

    Generalized-ensemble algorithms in temperature space have become popular tools to enhance conformational sampling in biomolecular simulations. A random walk in temperature leads to a corresponding random walk in potential energy, which can be used to cross over energetic barriers and overcome the problem of quasi-nonergodicity. In this paper, we introduce two novel methods: simulated tempering distributed replica sampling (STDR) and virtual replica exchange (VREX). These methods are designed to address the practical issues inherent in the replica exchange (RE), simulated tempering (ST), and serial replica exchange (SREM) algorithms. RE requires a large, dedicated, and homogeneous cluster of CPUs to function efficiently when applied to complex systems. ST and SREM both have the drawback of requiring extensive initial simulations, possibly adaptive, for the calculation of weight factors or potential energy distribution functions. STDR and VREX alleviate the need for lengthy initial simulations, and for synchronization and extensive communication between replicas. Both methods are therefore suitable for distributed or heterogeneous computing platforms. We perform an objective comparison of all five algorithms in terms of both implementation issues and sampling efficiency. We use disordered peptides in explicit water as test systems, for a total simulation time of over 42 μs. Efficiency is defined in terms of both structural convergence and temperature diffusion, and we show that these definitions of efficiency are in fact correlated. Importantly, we find that ST-based methods exhibit faster temperature diffusion and correspondingly faster convergence of structural properties compared to RE-based methods. Within the RE-based methods, VREX is superior to both SREM and RE. On the basis of our observations, we conclude that ST is ideal for simple systems, while STDR is well-suited for complex systems.

  7. A novel sampling method for multiple multiscale targets from scattering amplitudes at a fixed frequency

    Science.gov (United States)

    Liu, Xiaodong

    2017-08-01

    A sampling method by using scattering amplitude is proposed for shape and location reconstruction in inverse acoustic scattering problems. Only matrix multiplication is involved in the computation, thus the novel sampling method is very easy and simple to implement. With the help of the factorization of the far field operator, we establish an inf-criterion for characterization of underlying scatterers. This result is then used to give a lower bound of the proposed indicator functional for sampling points inside the scatterers. While for the sampling points outside the scatterers, we show that the indicator functional decays like the bessel functions as the sampling point goes away from the boundary of the scatterers. We also show that the proposed indicator functional continuously depends on the scattering amplitude, this further implies that the novel sampling method is extremely stable with respect to errors in the data. Different to the classical sampling method such as the linear sampling method or the factorization method, from the numerical point of view, the novel indicator takes its maximum near the boundary of the underlying target and decays like the bessel functions as the sampling points go away from the boundary. The numerical simulations also show that the proposed sampling method can deal with multiple multiscale case, even the different components are close to each other.

  8. A standardized method for sampling and extraction methods for quantifying microplastics in beach sand.

    Science.gov (United States)

    Besley, Aiken; Vijver, Martina G; Behrens, Paul; Bosker, Thijs

    2017-01-15

    Microplastics are ubiquitous in the environment, are frequently ingested by organisms, and may potentially cause harm. A range of studies have found significant levels of microplastics in beach sand. However, there is a considerable amount of methodological variability among these studies. Methodological variation currently limits comparisons as there is no standard procedure for sampling or extraction of microplastics. We identify key sampling and extraction procedures across the literature through a detailed review. We find that sampling depth, sampling location, number of repeat extractions, and settling times are the critical parameters of variation. Next, using a case-study we determine whether and to what extent these differences impact study outcomes. By investigating the common practices identified in the literature with the case-study, we provide a standard operating procedure for sampling and extracting microplastics from beach sand. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Methods of sampling airborne fungi in working environments of waste treatment facilities.

    Science.gov (United States)

    Černá, Kristýna; Wittlingerová, Zdeňka; Zimová, Magdaléna; Janovský, Zdeněk

    2016-01-01

    The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. The total number of colony-forming units (CFU)/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p airborne fungi ranged 2×102-1.7×106 CFU/m3 when using the membrane filters (MF) method, and 3×102-6.4×104 CFU/m3 when using the surface air system (SAS) method. Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  10. Fast egg collection method greatly improves randomness of egg sampling in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Schou, Mads Fristrup

    2013-01-01

    When obtaining samples for population genetic studies, it is essential that the sampling is random. For Drosophila, one of the crucial steps in sampling experimental flies is the collection of eggs. Here an egg collection method is presented, which randomizes the eggs in a water column...... and diminishes environmental variance. This method was compared with a traditional egg collection method where eggs are collected directly from the medium. Within each method the observed and expected standard deviations of egg-to-adult viability were compared, whereby the difference in the randomness...... and to obtain a representative collection of genotypes, the method presented here is strongly recommended when collecting eggs from Drosophila....

  11. Wet-digestion of environmental sample using silver-mediated electrochemical method

    International Nuclear Information System (INIS)

    Kuwabara, Jun

    2010-01-01

    An application of silver-mediated electrochemical method to environmental samples as the effective digestion method for iodine analysis was tried. Usual digestion method for 129 I in many type of environmental sample is combustion method using quartz glass tube. Chemical yield of iodine on the combustion method reduce depending on the type of sample. The silver-mediated electrochemical method is expected to achieve very low loss of iodine. In this study, dried kombu (Laminaria) sample was tried to digest with electrochemical cell. At the case of 1g of sample, digestion was completed for about 24 hours under the electric condition of <10V and <2A. After the digestion, oxidized species of iodine was reduced to iodide by adding sodium sulfite. And then the precipitate of silver iodide was obtained. (author)

  12. Reliability of different methods used for forming of working samples in the laboratory for seed testing

    Directory of Open Access Journals (Sweden)

    Opra Branislava

    2000-01-01

    Full Text Available The testing of seed quality starts from the moment a sample is formed in a warehouse during processing or packaging of the seed. The seed sampling as the process of obtaining the working sample also assumes each step undertaken during its testing in the laboratory. With the aim of appropriate forming of a seed sample in the laboratory, the usage of seed divider is prescribed for large seeded species (such as seed the size of wheat or larger (ISTA Rules, 1999. The aim of this paper was the comparison of different methods used for obtaining the working samples of maize and wheat seeds using conical, soil and centrifugal dividers. The number of seed of added admixtures confirmed the reliability of working samples formation. To each maize sample (1000 g 10 seeds of the following admixtures were added: Zea mays L. (red pericarp, Hordeum vulgäre L., Triticum aestivum L., and Glycine max (L. Merr. Two methods were used for formation of maze seed working sample. To wheat samples (1000 g 10 seeds of each of the following species were added: Avena saliva (hulled seeds, Hordeum vulgäre L., Galium tricorne Stokes, and Polygonum lapatifolmm L. For formation of wheat seed working samples four methods were used. Optimum of 9, but not less than 7 seeds of admixture were due to be determined in the maize seed working sample, while for wheat, at least one seed of admixture was expected to be found in the working sample. The obtained results confirmed that the formation of the maize seed working samples was the most reliable when centrifugal divider, the first method was used (average of admixture - 9.37. From the observed admixtures the seed of Triticum aestivum L. was the most uniformly distributed, the first method also being used (6.93. The second method gains high average values satisfying the given criterion, but it should be used with previous homogenization of the sample being tested. The forming of wheat seed working samples is the most reliable if the

  13. Suitability of the line intersect method for sampling hardwood logging residues

    Science.gov (United States)

    A. Jeff Martin

    1976-01-01

    The line intersect method of sampling logging residues was tested in Appalachian hardwoods and was found to provide unbiased estimates of the volume of residue in cubic feet per acre. Thirty-two chains of sample line were established on each of sixteen 1-acre plots on cutover areas in a variety of conditions. Estimates from these samples were then compared to actual...

  14. Methods and devices for hyperpolarising and melting NMR samples in a cryostat

    DEFF Research Database (Denmark)

    Ardenkjaer-Larsen, Jan Henrik; Axelsson, Oskar H. E.; Golman, Klaes Koppel

    2006-01-01

    The present invention relates to devices and method for melting solid polarised sample while retaining a high level of polarisation. In an embodiment of the present invention a sample is polarised in a sample-retaining cup 9 in a strong magnetic field in a polarising means 3a, 3b, 3c in a cryosta...

  15. Pollution evaluation in the Shahrood River: Do physico-chemical and macroinvertebrate-based indices indicate same responses to anthropogenic activities?

    Science.gov (United States)

    Sharifinia, Moslem; Mahmoudifard, Abbas; Imanpour Namin, Javid; Ramezanpour, Zohreh; Yap, Chee Kong

    2016-09-01

    This study evaluates the impact of anthropogenic activities on the Shahrood River using water physico-chemical variables and macroinvertebrates data sets obtained over a period of 12 months between February 2012 and February 2013 at 8 sampling sites. Biotic indices i.e. FBI and BMWP based on macroinvertebrates and physico-chemical indices (MPI, HPI and NSF-WQI) were employed to evaluate the water quality status in connection with natural- and human-induced pressures. Based on physico-chemical indices, water quality was categorized as low polluted level and it is suitable for drinking purposes. The water quality based on biotic indices was related to the anthropic activities; a clear deterioration of the water quality was observed from upstream to downstream sites. The water quality along the river changed from very good (class I; reference sites) to good (class II; midstream sites) and turned into moderate (class III) and poor (class IV) quality (downstream sites). These findings indicate that biotic indices are more powerful indicators in assessing water quality than physico-chemical indices. Allocapnia, Glossosoma and Hesperoperla were exclusively related to least disturbed sites, and Naididae, Orthocladiinae and Ecdyonurus were found in sites showing notable degradation. Our results recommended that the use of macroinvertebrates could be employed as a cost-effective tool for biomonitoring and controlling of polluted riverine ecosystems in the Middle East. Finally, the results from this study may be useful not only for developing countries, but also for any organization struggling to use macroinvertebrate based indices with restricted financial resources and knowledge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Effects of the “Run-of-River” Hydro Scheme on Macroinvertebrate Communities and Habitat Conditions in a Mountain River of Northeastern China

    Directory of Open Access Journals (Sweden)

    Haoran Wang

    2016-01-01

    Full Text Available The main objective of this study was to quantify the impacts of the run of river (ROR scheme on the instream habitat and macroinvertebrate community. We sampled the macroinvertebrate assemblages and collected the habitat variables above and below an ROR hydropower plant: Aotou plant in the Hailang River, China. The effects of the ROR scheme on habitat conditions were examined using regulation-related variables, most of which, particularly the hydrological variables and substrate composition, presented spatial variations along the downstream direction, contributing to heterogeneous conditions between reaches. The macroinvertebrate richness, the density and the diversity metrics showed significant decreases in the “depleted” reach compared with the upper and lower reaches. Approximately 75% of reach-averaged densities and 50% of taxa richness suffered decreases in the “depleted” reach compared with the upper reach. Furthermore, functional feeding groups also showed distinct site differences along the channel. The relative abundance of both collector-gatherers and the scrapers reduced considerably at the “depleted” sites, particularly at the site immediately downstream of the weir. The total variance in the the functional feeding group (FFG data explained by Canonical correlation analysis (CCA was more than 81.4% and the high-loadings factors were depth, flow velocity, DO and substrate composition. We demonstrated that flow diversion at the 75% level and an in-channel barrier, due to the ROR scheme, are likely to lead to poor habitat conditions and decrease both the abundance and the diversity of macroinvertebrates in reaches influenced by water diversion.

  17. Development of a Macroinvertebrate - based Index of Biotic Integrity (M-IBI for Colombo-Sri Jayawardhanapura Canal System (A new approach to assess stream/ wetland health

    Directory of Open Access Journals (Sweden)

    N. Nilakarawasam

    2012-05-01

    Full Text Available Macroinvertebrates have been identified as excellent indicators of stream (wetland health as they respond rapidly to environmental changers and provide short to medium term pollution history records. Current study was aimed to develop a Macroinvertebrate-based Index of Biotic Integrity (M-IBI to monitor stream health of Colombo-Sri Jayawardhanapura canal system. Macroinvertebrates were sampled using a D-framed kick net from ten stations during the period of Nov 2008 to June 2009. Habitat characteristics and some water quality parameters also recorded. For the index development, those ten stations were grouped into two as ’Reference’ and ‘Degraded’ based on their habitat characteristics and some water quality parameters. Then 41vcandidate metrics were nominated for statistical analysis process. After considering their sensitivity to stream impairment, ability of showing exceptionally strong discrimination between reference and degraded sites and less redundancy, ten candidate metrics were selected for M-IBI development. Validity of the index was tested with a new independent data set. Scores acquired for these data set were positively correlated with DO values (r = 0.578. That concluded the potential of using M-IBI developed for biological monitoring and improving biotic integrity of streams and wetlands.

  18. Fish but Not Macroinvertebrates Promote Trophic Cascading Effects in High Density Submersed Plant Experimental Lake Food Webs in Two Contrasting Climate Regions

    Directory of Open Access Journals (Sweden)

    Carlos Iglesias

    2017-07-01

    Full Text Available Predators play a key role in the functioning of shallow lakes. Differences between the response of temperate and subtropical systems to fish predation have been proposed, but experimental evidence is scarce. To elucidate cascading effects produced by predators in contrasting climatic zones, we conducted a mesocosm experiment in three pairs of lakes in Uruguay and Denmark. We used two typical planktivorous-omnivorous fish species (Jenynsia multidentata + Cnesterodon decemmaculatus and Gasterosteus aculeatus + Perca fluviatilis and one littoral omnivorous-predatory macroinvertebrate (Palaemonetes argentinus and Gammarus lacustris, alone and combined, in numbers resembling natural densities. Fish predation on zooplankton increased phytoplankton biomass in both climate zones, whereas the effects of predatory macroinvertebrates on zooplankton and phytoplankton were not significant in either climate zone. Macroinvertebrates (that freely colonized the sampling devices were diminished by fish in both climate areas; however, periphyton biomass did not vary among treatments. Our experiments demonstrated that fish affected the structure of both planktonic and littoral herbivorous communities in both climate regions, with a visible positive cascading effect on phytoplankton biomass, but no effects on periphyton. Altogether, fish impacts appeared to be a strong driver of turbid water conditions in shallow lakes regardless of climatic zone by indirectly contributing to increasing phytoplankton biomass.

  19. Serum chromium levels sampled with steel needle versus plastic IV cannula. Does method matter?

    DEFF Research Database (Denmark)

    Penny, Jeannette Ø; Overgaard, Søren

    2010-01-01

    PURPOSE: Modern metal-on-metal (MoM) joint articulations releases metal ions to the body. Research tries to establish how much this elevates metal ion levels and whether it causes adverse effects. The steel needle that samples the blood may introduce additional chromium to the sample thereby...... causing bias. This study aimed to test that theory. METHODS: We compared serum chromium values for two sampling methods, steel needle and IV plastic cannula, as well as sampling sequence in 16 healthy volunteers. RESULTS: We found statistically significant chromium contamination from the steel needle...... with mean differences between the two methods of 0.073 ng/mL, for the first sample, and 0.033 ng/mL for the second. No difference was found between the first and second plastic sample. The first steel needle sample contained an average of 0.047 ng/mL more than the second. This difference was only borderline...

  20. A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation.

    Science.gov (United States)

    Li, Song; Cao, Xupeng; Wang, Yan; Zhu, Zhen; Zhang, Haowei; Xue, Song; Tian, Jing

    2017-11-01

    With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.

  1. Universal nucleic acids sample preparation method for cells, spores and their mixture

    Science.gov (United States)

    Bavykin, Sergei [Darien, IL

    2011-01-18

    The present invention relates to a method for extracting nucleic acids from biological samples. More specifically the invention relates to a universal method for extracting nucleic acids from unidentified biological samples. An advantage of the presently invented method is its ability to effectively and efficiently extract nucleic acids from a variety of different cell types including but not limited to prokaryotic or eukaryotic cells and/or recalcitrant organisms (i.e. spores). Unlike prior art methods which are focused on extracting nucleic acids from vegetative cell or spores, the present invention effectively extracts nucleic acids from spores, multiple cell types or mixtures thereof using a single method. Important that the invented method has demonstrated an ability to extract nucleic acids from spores and vegetative bacterial cells with similar levels effectiveness. The invented method employs a multi-step protocol which erodes the cell structure of the biological sample, isolates, labels, fragments nucleic acids and purifies labeled samples from the excess of dye.

  2. Some refinements on the comparison of areal sampling methods via simulation

    Science.gov (United States)

    Jeffrey Gove

    2017-01-01

    The design of forest inventories and development of new sampling methods useful in such inventories normally have a two-fold target of design unbiasedness and minimum variance in mind. Many considerations such as costs go into the choices of sampling method for operational and other levels of inventory. However, the variance in terms of meeting a specified level of...

  3. Evaluation of beef trim sampling methods for detection of Shiga toxin-producing Escherichia coli (STEC)

    Science.gov (United States)

    Presence of Shiga toxin-producing Escherichia coli (STEC) is a major concern in ground beef. Several methods for sampling beef trim prior to grinding are currently used in the beef industry. The purpose of this study was to determine the efficacy of the sampling methods for detecting STEC in beef ...

  4. Sampling Methods and the Accredited Population in Athletic Training Education Research

    Science.gov (United States)

    Carr, W. David; Volberding, Jennifer

    2009-01-01

    Context: We describe methods of sampling the widely-studied, yet poorly defined, population of accredited athletic training education programs (ATEPs). Objective: There are two purposes to this study; first to describe the incidence and types of sampling methods used in athletic training education research, and second to clearly define the…

  5. Methods for assessing the impact of avermectins on the decomposer community of sheep pastures.

    Science.gov (United States)

    King, K L

    1993-06-01

    This paper outlines methods which can be used in the field assessment of potentially toxic chemicals such as the avermectins. The procedures focus on measuring the effects of the drug on decomposer organisms and the nutrient cycling process in pastures grazed by sheep. Measurements of decomposer activity are described along with methods for determining dry and organic matter loss and mineral loss from dung to the underlying soil. Sampling methods for both micro- and macro-invertebrates are discussed along with determination of the percentage infection of plant roots with vesicular-arbuscular mycorrhizal fungi. An integrated sampling unit for assessing the ecotoxicity of ivermectin in pastures grazed by sheep is presented.

  6. Ionizing radiation as optimization method for aluminum detection from drinking water samples

    International Nuclear Information System (INIS)

    Bazante-Yamguish, Renata; Geraldo, Aurea Beatriz C.; Moura, Eduardo; Manzoli, Jose Eduardo

    2013-01-01

    The presence of organic compounds in water samples is often responsible for metal complexation; depending on the analytic method, the organic fraction may dissemble the evaluation of the real values of metal concentration. Pre-treatment of the samples is advised when organic compounds are interfering agents, and thus sample mineralization may be accomplished by several chemical and/or physical methods. Here, the ionizing radiation was used as an advanced oxidation process (AOP), for sample pre-treatment before the analytic determination of total and dissolved aluminum by ICP-OES in drinking water samples from wells and spring source located at Billings dam region. Before irradiation, the spring source and wells' samples showed aluminum levels of 0.020 mg/l and 0.2 mg/l respectively; after irradiation, both samples showed a 8-fold increase of aluminum concentration. These results are discussed considering other physical and chemical parameters and peculiarities of sample sources. (author)

  7. Optical method for the characterization of laterally patterned samples in integrated circuits

    Science.gov (United States)

    Maris, Humphrey J [Barrington, RI

    2009-03-17

    Disclosed is a method for characterizing a sample having a structure disposed on or within the sample, comprising the steps of applying a first pulse of light to a surface of the sample for creating a propagating strain pulse in the sample, applying a second pulse of light to the surface so that the second pulse of light interacts with the propagating strain pulse in the sample, sensing from a reflection of the second pulse a change in optical response of the sample, and relating a time of occurrence of the change in optical response to at least one dimension of the structure.

  8. Purposeful Sampling for Qualitative Data Collection and Analysis in Mixed Method Implementation Research.

    Science.gov (United States)

    Palinkas, Lawrence A; Horwitz, Sarah M; Green, Carla A; Wisdom, Jennifer P; Duan, Naihua; Hoagwood, Kimberly

    2015-09-01

    Purposeful sampling is widely used in qualitative research for the identification and selection of information-rich cases related to the phenomenon of interest. Although there are several different purposeful sampling strategies, criterion sampling appears to be used most commonly in implementation research. However, combining sampling strategies may be more appropriate to the aims of implementation research and more consistent with recent developments in quantitative methods. This paper reviews the principles and practice of purposeful sampling in implementation research, summarizes types and categories of purposeful sampling strategies and provides a set of recommendations for use of single strategy or multistage strategy designs, particularly for state implementation research.

  9. Purposeful sampling for qualitative data collection and analysis in mixed method implementation research

    Science.gov (United States)

    Palinkas, Lawrence A.; Horwitz, Sarah M.; Green, Carla A.; Wisdom, Jennifer P.; Duan, Naihua; Hoagwood, Kimberly

    2013-01-01

    Purposeful sampling is widely used in qualitative research for the identification and selection of information-rich cases related to the phenomenon of interest. Although there are several different purposeful sampling strategies, criterion sampling appears to be used most commonly in implementation research. However, combining sampling strategies may be more appropriate to the aims of implementation research and more consistent with recent developments in quantitative methods. This paper reviews the principles and practice of purposeful sampling in implementation research, summarizes types and categories of purposeful sampling strategies and provides a set of recommendations for use of single strategy or multistage strategy designs, particularly for state implementation research. PMID:24193818

  10. Quantitative method of determining beryllium or a compound thereof in a sample

    Science.gov (United States)

    McCleskey, T. Mark; Ehler, Deborah S.; John, Kevin D.; Burrell, Anthony K.; Collis, Gavin E.; Minogue, Edel M.; Warner, Benjamin P.

    2010-08-24

    A method of determining beryllium or a beryllium compound thereof in a sample, includes providing a sample suspected of comprising beryllium or a compound thereof, extracting beryllium or a compound thereof from the sample by dissolving in a solution, adding a fluorescent indicator to the solution to thereby bind any beryllium or a compound thereof to the fluorescent indicator, and determining the presence or amount of any beryllium or a compound thereof in the sample by measuring fluorescence.

  11. Estimation of the sugar cane cultivated area from LANDSAT images using the two phase sampling method

    Science.gov (United States)

    Parada, N. D. J. (Principal Investigator); Cappelletti, C. A.; Mendonca, F. J.; Lee, D. C. L.; Shimabukuro, Y. E.

    1982-01-01

    A two phase sampling method and the optimal sampling segment dimensions for the estimation of sugar cane cultivated area were developed. This technique employs visual interpretations of LANDSAT images and panchromatic aerial photographs considered as the ground truth. The estimates, as a mean value of 100 simulated samples, represent 99.3% of the true value with a CV of approximately 1%; the relative efficiency of the two phase design was 157% when compared with a one phase aerial photographs sample.

  12. Estimating HIES Data through Ratio and Regression Methods for Different Sampling Designs

    Directory of Open Access Journals (Sweden)

    Faqir Muhammad

    2007-01-01

    Full Text Available In this study, comparison has been made for different sampling designs, using the HIES data of North West Frontier Province (NWFP for 2001-02 and 1998-99 collected from the Federal Bureau of Statistics, Statistical Division, Government of Pakistan, Islamabad. The performance of the estimators has also been considered using bootstrap and Jacknife. A two-stage stratified random sample design is adopted by HIES. In the first stage, enumeration blocks and villages are treated as the first stage Primary Sampling Units (PSU. The sample PSU’s are selected with probability proportional to size. Secondary Sampling Units (SSU i.e., households are selected by systematic sampling with a random start. They have used a single study variable. We have compared the HIES technique with some other designs, which are: Stratified Simple Random Sampling. Stratified Systematic Sampling. Stratified Ranked Set Sampling. Stratified Two Phase Sampling. Ratio and Regression methods were applied with two study variables, which are: Income (y and Household sizes (x. Jacknife and Bootstrap are used for variance replication. Simple Random Sampling with sample size (462 to 561 gave moderate variances both by Jacknife and Bootstrap. By applying Systematic Sampling, we received moderate variance with sample size (467. In Jacknife with Systematic Sampling, we obtained variance of regression estimator greater than that of ratio estimator for a sample size (467 to 631. At a sample size (952 variance of ratio estimator gets greater than that of regression estimator. The most efficient design comes out to be Ranked set sampling compared with other designs. The Ranked set sampling with jackknife and bootstrap, gives minimum variance even with the smallest sample size (467. Two Phase sampling gave poor performance. Multi-stage sampling applied by HIES gave large variances especially if used with a single study variable.

  13. Two media method for linear attenuation coefficient determination of irregular soil samples

    International Nuclear Information System (INIS)

    Vici, Carlos Henrique Georges

    2004-01-01

    In several situations of nuclear applications, the knowledge of gamma-ray linear attenuation coefficient for irregular samples is necessary, such as in soil physics and geology. This work presents the validation of a methodology for the determination of the linear attenuation coefficient (μ) of irregular shape samples, in such a way that it is not necessary to know the thickness of the considered sample. With this methodology irregular soil samples (undeformed field samples) from Londrina region, north of Parana were studied. It was employed the two media method for the μ determination. It consists of the μ determination through the measurement of a gamma-ray beam attenuation by the sample sequentially immersed in two different media, with known and appropriately chosen attenuation coefficients. For comparison, the theoretical value of μ was calculated by the product of the mass attenuation coefficient, obtained by the WinXcom code, and the measured value of the density sample. This software employs the chemical composition of the samples and supplies a table of the mass attenuation coefficients versus the photon energy. To verify the validity of the two media method, compared with the simple gamma ray transmission method, regular pome stone samples were used. With these results for the attenuation coefficients and their respective deviations, it was possible to compare the two methods. In this way we concluded that the two media method is a good tool for the determination of the linear attenuation coefficient of irregular materials, particularly in the study of soils samples. (author)

  14. Assessment of Streamside Management Zones for Conserving Benthic Macroinvertebrate Communities Following Timber Harvest in Eastern Kentucky Headwater Catchments

    Directory of Open Access Journals (Sweden)

    Joshua K. Adkins

    2016-06-01

    Full Text Available Headwater streams generally comprise the majority of stream area in a watershed and can have a strong influence on downstream food webs. Our objective was to determine the effect of altering streamside management zone (SMZ configurations on headwater aquatic insect communities. Timber harvests were implemented within six watersheds in eastern Kentucky. The SMZ configurations varied in width, canopy retention and best management practice (BMP utilization at the watershed scale. Benthic macroinvertebrate samples collected one year before and four years after harvest indicated few differences among treatments, although post-treatment abundance was elevated in some of the treatment streams relative to the unharvested controls. Jaccard index values were similar across SMZ treatments after logging, indicating strong community overlap. These findings suggest that stream invertebrate communities did respond to the timber harvest, though not negatively. Results also suggest that SMZ criteria for aquatic habitats in steeply sloping topography, including at least 50 percent canopy retention and widths of at least 16.8 m, appear to be adequate for protecting benthic macroinvertebrate communities from logging impacts.

  15. BIOLOGICAL WATER QUALITY ASSESSMENT OF THE WHITECLAWED CRAYFISH HABITAT BASED ON MACROINVERTEBRATE COMMUNITIES: USEFULNESS FOR ITS CONSERVATION

    Directory of Open Access Journals (Sweden)

    GRANDJEAN F.

    2003-04-01

    Full Text Available A survey of the macroinvertebrates of three brooks harbouring the white-clawed crayfish was conducted in Haute-Vienne department (France. Its aim was to increase our understanding of these ecosystems to help the conservation of A. pallipes. These brooks run through pastoral areas with well-developed riparian vegetation, which offers an important shade. Water temperature, dissolved oxygen concentration, pH, and conductivity fell within the ranges found for this species. A total of 34, 31, 29 taxa and 1 502, 1 364, 2 707 individuals of macrobenthos were collected in Holme, Besque and Bellecombe streams, respectively. Results showed good to very good water quality with IBGN scores ranging from 15 (Bellecombe to 17 (Holme and Besque, reflecting a limited impact of the anthropogenic disturbances. Taxa diversity were high for Holme and Besque with Shannon index around 3.2, translating a great heterogeneity of habitat and an equilibrated faunal community. Bellecombe showed a limited diversity with Shannon index of 1.42, resulting from the presence of numberous Chironomidae. This brook suffers probably weak organic pollution which could be related to the low water flow observed during the sampling. The similarity test according to Jaccard index showed high percentage of common taxa among ETP (Ephemeroptera-Trichoptera-Plecoptera between all sites. The high similarity of benthic macroinvertebrate communities could be an useful criteria to identify brooks for restocking purpose.

  16. Correlation study of some physico-chemical parameters and benthic macroinvertebrates metrics on the ecological impacts of flriculture industries along Wedecha River, Debrezeit, Ethiopia

    Directory of Open Access Journals (Sweden)

    Sisay Misganaw Tamiru

    2017-10-01

    Full Text Available Objective: To assess the quality of water using biological and chemical information correlation study. Methods: A total of 6 sites, one reference site less impaired to represent natural conditions from upstream, and 5 impaired sites in the downstream were sampled for macroinvertebrates and physicochemical parameters. Results: In the polluted sites with high nutrient enrichment and organic loading, only organisms with special physiological and morphological adaptations were found, such as Hydrobiidae, Physidae and Viviparidae snails. Physicochemical parameters: electrical conductivity, chemical oxygen demand, biological oxygen demand, sulphate, orthophosphate and nitrate-nitrogen and metrics: percent of Mollusca, percent of Physidae and percent of dominant taxa were used for monitoring, and expected to have strong positive relation with increasing disturbance. Conclusions: Therefore, floriculture industries wastewater discharged to the nearby rivers has enormous effect on the degradation of the ecosystem. To sustain the ecological conditions of the nearby rivers, wastewater treatment and environmental audit were suggested. Environmental assessment and environmental audit enable the floriculturist to keep humans and the environment safe. Taking care of workers, soil, water and the environment has to be seen with great care and caution because it is difficult to maintain a healthy community and carry out development in a degraded environment.

  17. Macroinvertebrate community response to acid mine drainage in rivers of the High Andes (Bolivia)

    International Nuclear Information System (INIS)

    Van Damme, Paul Andre; Hamel, Caroli; Ayala, Alfredo; Bervoets, Lieven

    2008-01-01

    Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the taxon diversity of the macroinvertebrate community at the family level was low. The concentrations of Cd, Cu, Zn, Pb and Ni at mining sites were higher than at unpolluted sites. The pH of the water was alkaline (7.0-8.5) in unpolluted sites, whereas it dropped to very low values (<3) at mining sites. Redundancy Analysis (RDA) showed that pH was the best predictor of macroinvertebrate community richness. The number of macroinvertebrate families decreased gradually with increasing acidity, both in pools and riffles, though it is suggested that riffle communities were more affected because they are in closer contact with the acid water. - Community response to AMD

  18. Soft sediment dwelling macro-invertebrates of Rajapur Bay, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Parulekar, A.H.

    Thirtyfour species of soft sediment dwelling macro-invertebrates were recorded in Rajapur Bay at the proposed effluent discharge location of nuclear power plant. The fauna mainly composed of polychaetes (42.52%), molluscs (39.03%), crustaceans (7...

  19. Benthic Macroinvertebrate Assemblages in the Near Coastal Zone of Lake Erie

    Science.gov (United States)

    Benthic macroinvertebrate assemblages have been used as indicators of ecological condition because their responses integrate localized environmental conditions of the sediments and overlying water. Assemblages of benthic invertebrates in the near coastal region are of particular...

  20. Development of a multimetric index based on macroinvertebrates for drainage ditch networks in agricultural areas.

    NARCIS (Netherlands)

    Verdonschot, R.C.M.; Keizer-Vlek, H.E.; Verdonschot, P.F.M.

    2012-01-01

    Drainage ditches are a prominent feature of many intensively managed agricultural areas. These small, shallow, line-shaped waterbodies could harbor a rich macroinvertebrate community, resembling that of natural small lentic ecosystems. Despite their high biodiversity potential, many ditch ecosystems

  1. Numerical analyses of soft bottom macroinvertebrates to diagnose the pollution in tropical coastal waters

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Rodrigues, N.R.

    of techniques to assess the impact of pollution on benthic community structure. Hence, to test this hypotheses some of the univariate and multivariate techniques were applied to soft bottom macro-invertebrates data of coastal waters of Mangalore, central west...

  2. Impact of Urban Effluents on the Macroinvertebrates of a Creek in ...

    African Journals Online (AJOL)

    User

    The impact of effluents on the macroinvertebrate communities of an urban creek in ... of complying with the Environmental Protection Agency (EPA) guidelines are ..... Business. World Water Council, Earthscan. Publications Ltd. London, UK.

  3. [Sample preparation methods for chromatographic analysis of organic components in atmospheric particulate matter].

    Science.gov (United States)

    Hao, Liang; Wu, Dapeng; Guan, Yafeng

    2014-09-01

    The determination of organic composition in atmospheric particulate matter (PM) is of great importance in understanding how PM affects human health, environment, climate, and ecosystem. Organic components are also the scientific basis for emission source tracking, PM regulation and risk management. Therefore, the molecular characterization of the organic fraction of PM has become one of the priority research issues in the field of environmental analysis. Due to the extreme complexity of PM samples, chromatographic methods have been the chief selection. The common procedure for the analysis of organic components in PM includes several steps: sample collection on the fiber filters, sample preparation (transform the sample into a form suitable for chromatographic analysis), analysis by chromatographic methods. Among these steps, the sample preparation methods will largely determine the throughput and the data quality. Solvent extraction methods followed by sample pretreatment (e. g. pre-separation, derivatization, pre-concentration) have long been used for PM sample analysis, and thermal desorption methods have also mainly focused on the non-polar organic component analysis in PM. In this paper, the sample preparation methods prior to chromatographic analysis of organic components in PM are reviewed comprehensively, and the corresponding merits and limitations of each method are also briefly discussed.

  4. Estimation of the sensitivity of various environmental sampling methods for detection of Salmonella in duck flocks.

    Science.gov (United States)

    Arnold, Mark E; Mueller-Doblies, Doris; Gosling, Rebecca J; Martelli, Francesca; Davies, Robert H

    2015-01-01

    Reports of Salmonella in ducks in the UK currently rely upon voluntary submissions from the industry, and as there is no harmonized statutory monitoring and control programme, it is difficult to compare data from different years in order to evaluate any trends in Salmonella prevalence in relation to sampling methodology. Therefore, the aim of this project was to assess the sensitivity of a selection of environmental sampling methods, including the sampling of faeces, dust and water troughs or bowls for the detection of Salmonella in duck flocks, and a range of sampling methods were applied to 67 duck flocks. Bayesian methods in the absence of a gold standard were used to provide estimates of the sensitivity of each of the sampling methods relative to the within-flock prevalence. There was a large influence of the within-flock prevalence on the sensitivity of all sample types, with sensitivity reducing as the within-flock prevalence reduced. Boot swabs (individual and pool of four), swabs of faecally contaminated areas and whole house hand-held fabric swabs showed the overall highest sensitivity for low-prevalence flocks and are recommended for use to detect Salmonella in duck flocks. The sample type with the highest proportion positive was a pool of four hair nets used as boot swabs, but this was not the most sensitive sample for low-prevalence flocks. All the environmental sampling types (faeces swabs, litter pinches, drag swabs, water trough samples and dust) had higher sensitivity than individual faeces sampling. None of the methods consistently identified all the positive flocks, and at least 10 samples would be required for even the most sensitive method (pool of four boot swabs) to detect a 5% prevalence. The sampling of dust had a low sensitivity and is not recommended for ducks.

  5. The impact of different blood sampling methods on laboratory rats under different types of anaesthesia

    DEFF Research Database (Denmark)

    Toft, Martin Fitzner; Petersen, Mikke Haxø; Dragsted, Nils

    2006-01-01

    for rats sampled from the tail vein, which showed fluctuations in body temperature in excess of 30 h after sampling. Increases in heart rate and blood pressure within the first hours after sampling indicated that periorbital puncture was the method that had the largest acute impact on the rats......Rats with implanted telemetry transponders were blood sampled by jugular puncture, periorbital puncture or tail vein puncture, or sampled by jugular puncture in carbon dioxide (CO?), isoflurane or without anaesthesia in a crossover design. Heart rate, blood pressure and body temperature were...... registered for three days after sampling. Initially blood pressure increased, but shortly after sampling it decreased, which led to increased heart rate. Sampling induced rapid fluctuations in body temperature, and an increase in body temperature. Generally, rats recovered from sampling within 2-3 h, except...

  6. Use of Monte Carlo Bootstrap Method in the Analysis of Sample Sufficiency for Radioecological Data

    International Nuclear Information System (INIS)

    Silva, A. N. C. da; Amaral, R. S.; Araujo Santos Jr, J.; Wilson Vieira, J.; Lima, F. R. de A.

    2015-01-01

    There are operational difficulties in obtaining samples for radioecological studies. Population data may no longer be available during the study and obtaining new samples may not be possible. These problems do the researcher sometimes work with a small number of data. Therefore, it is difficult to know whether the number of samples will be sufficient to estimate the desired parameter. Hence, it is critical do the analysis of sample sufficiency. It is not interesting uses the classical methods of statistic to analyze sample sufficiency in Radioecology, because naturally occurring radionuclides have a random distribution in soil, usually arise outliers and gaps with missing values. The present work was developed aiming to apply the Monte Carlo Bootstrap method in the analysis of sample sufficiency with quantitative estimation of a single variable such as specific activity of a natural radioisotope present in plants. The pseudo population was a small sample with 14 values of specific activity of 226 Ra in forage palm (Opuntia spp.). Using the R software was performed a computational procedure to calculate the number of the sample values. The re sampling process with replacement took the 14 values of original sample and produced 10,000 bootstrap samples for each round. Then was calculated the estimated average θ for samples with 2, 5, 8, 11 and 14 values randomly selected. The results showed that if the researcher work with only 11 sample values, the average parameter will be within a confidence interval with 90% probability . (Author)

  7. Validation of the Cristallini Sampling Method for UF6 by High Precision Double-Spike Measurements

    OpenAIRE

    RICHTER STEPHAN; JAKOBSSON ULF; HIESS JOE; AMARAGGI D.

    2017-01-01

    The so-called "Cristallini Method" for sampling of UF6 by adsorption and hydrolysis in alumina pellets inside a fluorothene P-10 tube was developed by the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) several years ago. This method has several advantages compared to the currently used sampling method, for which UF6 is distilled into a stainless steel tube for transportation, with hydrolysis and isotopic analysis being performed after shipping to the analyt...

  8. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    Energy Technology Data Exchange (ETDEWEB)

    Adamic, M.L., E-mail: Mary.Adamic@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83402 (United States); Lister, T.E.; Dufek, E.J.; Jenson, D.D.; Olson, J.E. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83402 (United States); Vockenhuber, C. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Watrous, M.G. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83402 (United States)

    2015-10-15

    This paper presents an evaluation of an alternate method for preparing environmental samples for {sup 129}I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

  9. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    International Nuclear Information System (INIS)

    Adamic, M.L.; Lister, T.E.; Dufek, E.J.; Jenson, D.D.; Olson, J.E.; Vockenhuber, C.; Watrous, M.G.

    2015-01-01

    This paper presents an evaluation of an alternate method for preparing environmental samples for "1"2"9I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

  10. Method validation and uncertainty evaluation of organically bound tritium analysis in environmental sample.

    Science.gov (United States)

    Huang, Yan-Jun; Zeng, Fan; Zhang, Bing; Chen, Chao-Feng; Qin, Hong-Juan; Wu, Lian-Sheng; Guo, Gui-Yin; Yang, Li-Tao; Shang-Guan, Zhi-Hong

    2014-08-01

    The analytical method for organically bound tritium (OBT) was developed in our laboratory. The optimized operating conditions and parameters were established for sample drying, special combustion, distillation, and measurement on a liquid scintillation spectrometer (LSC). Selected types of OBT samples such as rice, corn, rapeseed, fresh lettuce and pork were analyzed for method validation of recovery rate reproducibility, the minimum detection concentration, and the uncertainty for typical low level environmental sample was evaluated. The combustion water recovery rate of different dried environmental sample was kept at about 80%, the minimum detection concentration of OBT ranged from 0.61 to 0.89 Bq/kg (dry weight), depending on the hydrogen content. It showed that this method is suitable for OBT analysis of environmental sample with stable recovery rate, and the combustion water yield of a sample with weight about 40 g would provide sufficient quantity for measurement on LSC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. The Effect of Community-Based Soil and Water Conservation Practices on Abundance and Diversity of Soil Macroinvertebrates in the Northern Highlands of Ethiopia

    Directory of Open Access Journals (Sweden)

    Mengistu Welemariam

    2018-04-01

    Full Text Available Soil and water conservation (SWC practices in the northern highlands of Ethiopia have important implications for land restoration and biodiversity recovery. The present study determined soil macroinvertebrate (SMI abundance and diversity in response to spatial conditions i.e., generated by different conservation practices, soil depth, and temporal seasonality with the wet and dry season. The SWC practices considered were exclosure + terrace, exclosure alone, terraces, and non-conserved grazing lands. Each SWC measure was selected in three sites that were considered as replications due to low heterogeneity in terms of human and livestock disturbances and biophysical factors. Soil macroinvertebrates were collected using a monolith according to tropical soil biology and fertility (TSBF method. The highest density (55% of SMI was found in exclosures followed by terraces 26%. Non-conserved communal grazing lands account for only 19% of the total. Shannon diversity index was significantly (P < 0.05 higher (1.21 in the exclosures supported with terraces and the lowest (0.9 was observed in the non-conserved communal grazing lands. Diversity was also significantly (P < 0.05 higher (1.26 in wet than dry season (0.70. The highest (41% Sorensen similarity index among SMI was found between exclosures with terraces and exclosures alone during the wet season. The lowest (20% Sorensen similarity index was found between terraces alone and exclosures with terraces in dry season. Soil macroinvertebrate abundance was higher in upper (0–10 cm than lower (10–20 and 20–30 cm soil depth. Soil macroinvertebrate abundance was positively and strongly correlated with soil moisture (R2 = 0.85 and soil organic carbon stock (R2 = 0.95. However, it was negatively (R2 = −0.71 correlated with bulk density. Generally, the abundance and diversity of SMI increased as exclosures and communal grazing lands are supported with terraces.

  12. Comparison of microstickies measurement methods. Part I, sample preparation and measurement methods

    Science.gov (United States)

    Mahendra R. Doshi; Angeles Blanco; Carlos Negro; Gilles M. Dorris; Carlos C. Castro; Axel Hamann; R. Daniel Haynes; Carl Houtman; Karen Scallon; Hans-Joachim Putz; Hans Johansson; R.A. Venditti; K. Copeland; H.-M. Chang

    2003-01-01

    Recently, we completed a project on the comparison of macrostickies measurement methods. Based on the success of the project, we decided to embark on this new project on comparison of microstickies measurement methods. When we started this project, there were some concerns and doubts principally due to the lack of an accepted definition of microstickies. However, we...

  13. An adaptive Monte Carlo method under emission point as sampling station for deep penetration calculation

    International Nuclear Information System (INIS)

    Wang, Ruihong; Yang, Shulin; Pei, Lucheng

    2011-01-01

    Deep penetration problem has been one of the difficult problems in shielding calculation with Monte Carlo method for several decades. In this paper, an adaptive technique under the emission point as a sampling station is presented. The main advantage is to choose the most suitable sampling number from the emission point station to get the minimum value of the total cost in the process of the random walk. Further, the related importance sampling method is also derived. The main principle is to define the importance function of the response due to the particle state and ensure the sampling number of the emission particle is proportional to the importance function. The numerical results show that the adaptive method under the emission point as a station could overcome the difficulty of underestimation to the result in some degree, and the related importance sampling method gets satisfied results as well. (author)

  14. Analysis of methods commonly used in biomedicine for treatment versus control comparison of very small samples.

    Science.gov (United States)

    Ristić-Djurović, Jasna L; Ćirković, Saša; Mladenović, Pavle; Romčević, Nebojša; Trbovich, Alexander M

    2018-04-01

    A rough estimate indicated that use of samples of size not larger than ten is not uncommon in biomedical research and that many of such studies are limited to strong effects due to sample sizes smaller than six. For data collected from biomedical experiments it is also often unknown if mathematical requirements incorporated in the sample comparison methods are satisfied. Computer simulated experiments were used to examine performance of methods for qualitative sample comparison and its dependence on the effectiveness of exposure, effect intensity, distribution of studied parameter values in the population, and sample size. The Type I and Type II errors, their average, as well as the maximal errors were considered. The sample size 9 and the t-test method with p = 5% ensured error smaller than 5% even for weak effects. For sample sizes 6-8 the same method enabled detection of weak effects with errors smaller than 20%. If the sample sizes were 3-5, weak effects could not be detected with an acceptable error; however, the smallest maximal error in the most general case that includes weak effects is granted by the standard error of the mean method. The increase of sample size from 5 to 9 led to seven times more accurate detection of weak effects. Strong effects were detected regardless of the sample size and method used. The minimal recommended sample size for biomedical experiments is 9. Use of smaller sizes and the method of their comparison should be justified by the objective of the experiment. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Seasonal comparison of aquatic macroinvertebrate assemblages in a flooded coastal freshwater marsh

    Science.gov (United States)

    Kang, Sung-Ryong; King, Sammy L.

    2013-01-01

    Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may decrease density, taxonomic diversity, and taxa richness. The principal objectives of this study are to characterize the seasonal aquatic macroinvertebrate assemblage in a freshwater emergent marsh and compare aquatic macroinvertebrate species composition, density, and taxonomic diversity to that of freshwater marsh ponds. We hypothesize that 1) freshwater emergent marsh has lower seasonal density and taxonomic diversity compared to that of freshwater marsh ponds; and 2) freshwater emergent marsh has lower taxa richness than freshwater marsh ponds. Seasonal aquatic macroinvertebrate density in freshwater emergent marsh ranged from 0 organisms/m2 (summer 2009) to 91.1 ± 20.53 organisms/m2 (mean ± SE; spring 2009). Density in spring was higher than in all other seasons. Taxonomic diversity did not differ and there were no unique species in the freshwater emergent marsh. Our data only partially support our first hypothesis as aquatic macroinvertebrate density and taxonomic diversity between freshwater emergent marsh and ponds did not differ in spring, fall, and winter but ponds supported higher macroinvertebrate densities than freshwater emergent marsh during summer. However, our data did not support our second hypothesis as taxa richness between freshwater emergent marsh and ponds did not statistically differ.

  16. Sampling for Patient Exit Interviews: Assessment of Methods Using Mathematical Derivation and Computer Simulations.

    Science.gov (United States)

    Geldsetzer, Pascal; Fink, Günther; Vaikath, Maria; Bärnighausen, Till

    2018-02-01

    (1) To evaluate the operational efficiency of various sampling methods for patient exit interviews; (2) to discuss under what circumstances each method yields an unbiased sample; and (3) to propose a new, operationally efficient, and unbiased sampling method. Literature review, mathematical derivation, and Monte Carlo simulations. Our simulations show that in patient exit interviews it is most operationally efficient if the interviewer, after completing an interview, selects the next patient exiting the clinical consultation. We demonstrate mathematically that this method yields a biased sample: patients who spend a longer time with the clinician are overrepresented. This bias can be removed by selecting the next patient who enters, rather than exits, the consultation room. We show that this sampling method is operationally more efficient than alternative methods (systematic and simple random sampling) in most primary health care settings. Under the assumption that the order in which patients enter the consultation room is unrelated to the length of time spent with the clinician and the interviewer, selecting the next patient entering the consultation room tends to be the operationally most efficient unbiased sampling method for patient exit interviews. © 2016 The Authors. Health Services Research published by Wiley Periodicals, Inc. on behalf of Health Research and Educational Trust.

  17. [Sampling methods for PM2.5 from stationary sources: a review].

    Science.gov (United States)

    Jiang, Jing-Kun; Deng, Jian-Guo; Li, Zhen; Li, Xing-Hua; Duan, Lei; Hao, Ji-Ming

    2014-05-01

    The new China national ambient air quality standard has been published in 2012 and will be implemented in 2016. To meet the requirements in this new standard, monitoring and controlling PM2,,5 emission from stationary sources are very important. However, so far there is no national standard method on sampling PM2.5 from stationary sources. Different sampling methods for PM2.5 from stationary sources and relevant international standards were reviewed in this study. It includes the methods for PM2.5 sampling in flue gas and the methods for PM2.5 sampling after dilution. Both advantages and disadvantages of these sampling methods were discussed. For environmental management, the method for PM2.5 sampling in flue gas such as impactor and virtual impactor was suggested as a standard to determine filterable PM2.5. To evaluate environmental and health effects of PM2.5 from stationary sources, standard dilution method for sampling of total PM2.5 should be established.

  18. Intercomparison study of sampling methods for the determination of polychlorinated biphenyl (PCB) in seawater

    International Nuclear Information System (INIS)

    Schulz-Bull, D.E.

    1999-01-01

    The determination of organic pollutants in seawater is a serious problem, as their concentrations in the water column are typical in the fg - ng/L range. Available methods therefore includes extensive sampling and laboratory work. The development of simple sampling techniques for organochlorines (e.g. passive sampling with semipermeable membrane device (SPMD), mussel watch) is required. Three methods for the measurement of trace organochlorines in seawater were investigated: (1) the filtration (GF/F) and extraction (XAD-2 resin) of seawater with an in-situ pumping system, (2) biological-accumulation by mussels (mytilus edulis) and (3) passive sampling with SPMD

  19. Probabilistic finite element stiffness of a laterally loaded monopile based on an improved asymptotic sampling method

    DEFF Research Database (Denmark)

    Vahdatirad, Mohammadjavad; Bayat, Mehdi; Andersen, Lars Vabbersgaard

    2015-01-01

    shear strength of clay. Normal and Sobol sampling are employed to provide the asymptotic sampling method to generate the probability distribution of the foundation stiffnesses. Monte Carlo simulation is used as a benchmark. Asymptotic sampling accompanied with Sobol quasi random sampling demonstrates......The mechanical responses of an offshore monopile foundation mounted in over-consolidated clay are calculated by employing a stochastic approach where a nonlinear p–y curve is incorporated with a finite element scheme. The random field theory is applied to represent a spatial variation for undrained...... an efficient method for estimating the probability distribution of stiffnesses for the offshore monopile foundation....

  20. Louisiana waterthrush and benthic macroinvertebrate response to shale gas development

    Science.gov (United States)

    Wood, Petra; Frantz, Mack W.; Becker, Douglas A.

    2016-01-01

    Because shale gas development is occurring over large landscapes and consequently is affecting many headwater streams, an understanding of its effects on headwater-stream faunal communities is needed. We examined effects of shale gas development (well pads and associated infrastructure) on Louisiana waterthrush Parkesia motacilla and benthic macroinvertebrate communities in 12 West Virginia headwater streams in 2011. Streams were classed as impacted (n = 6) or unimpacted (n = 6) by shale gas development. We quantified waterthrush demography (nest success, clutch size, number of fledglings, territory density), a waterthrush Habitat Suitability Index, a Rapid Bioassessment Protocol habitat index, and benthic macroinvertebrate metrics including a genus-level stream-quality index for each stream. We compared each benthic metric between impacted and unimpacted streams with a Student's t-test that incorporated adjustments for normalizing data. Impacted streams had lower genus-level stream-quality index scores; lower overall and Ephemeroptera, Plecoptera, and Trichoptera richness; fewer intolerant taxa, more tolerant taxa, and greater density of 0–3-mm individuals (P ≤ 0.10). We then used Pearson correlation to relate waterthrush metrics to benthic metrics across the 12 streams. Territory density (no. of territories/km of stream) was greater on streams with higher genus-level stream-quality index scores; greater density of all taxa and Ephemeroptera, Plecoptera, and Trichoptera taxa; and greater biomass. Clutch size was greater on streams with higher genus-level stream-quality index scores. Nest survival analyses (n = 43 nests) completed with Program MARK suggested minimal influence of benthic metrics compared with nest stage and Habitat Suitability Index score. Although our study spanned only one season, our results suggest that shale gas development affected waterthrush and benthic communities in the headwater streams we studied. Thus, these ecological effects of