WorldWideScience

Sample records for sample selection effects

  1. Effective traffic features selection algorithm for cyber-attacks samples

    Science.gov (United States)

    Li, Yihong; Liu, Fangzheng; Du, Zhenyu

    2018-05-01

    By studying the defense scheme of Network attacks, this paper propose an effective traffic features selection algorithm based on k-means++ clustering to deal with the problem of high dimensionality of traffic features which extracted from cyber-attacks samples. Firstly, this algorithm divide the original feature set into attack traffic feature set and background traffic feature set by the clustering. Then, we calculates the variation of clustering performance after removing a certain feature. Finally, evaluating the degree of distinctiveness of the feature vector according to the result. Among them, the effective feature vector is whose degree of distinctiveness exceeds the set threshold. The purpose of this paper is to select out the effective features from the extracted original feature set. In this way, it can reduce the dimensionality of the features so as to reduce the space-time overhead of subsequent detection. The experimental results show that the proposed algorithm is feasible and it has some advantages over other selection algorithms.

  2. Heterogeneous Causal Effects and Sample Selection Bias

    DEFF Research Database (Denmark)

    Breen, Richard; Choi, Seongsoo; Holm, Anders

    2015-01-01

    The role of education in the process of socioeconomic attainment is a topic of long standing interest to sociologists and economists. Recently there has been growing interest not only in estimating the average causal effect of education on outcomes such as earnings, but also in estimating how...... causal effects might vary over individuals or groups. In this paper we point out one of the under-appreciated hazards of seeking to estimate heterogeneous causal effects: conventional selection bias (that is, selection on baseline differences) can easily be mistaken for heterogeneity of causal effects....... This might lead us to find heterogeneous effects when the true effect is homogenous, or to wrongly estimate not only the magnitude but also the sign of heterogeneous effects. We apply a test for the robustness of heterogeneous causal effects in the face of varying degrees and patterns of selection bias...

  3. Risk Attitudes, Sample Selection and Attrition in a Longitudinal Field Experiment

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Lau, Morten Igel

    with respect to risk attitudes. Our design builds in explicit randomization on the incentives for participation. We show that there are significant sample selection effects on inferences about the extent of risk aversion, but that the effects of subsequent sample attrition are minimal. Ignoring sample...... selection leads to inferences that subjects in the population are more risk averse than they actually are. Correcting for sample selection and attrition affects utility curvature, but does not affect inferences about probability weighting. Properly accounting for sample selection and attrition effects leads...... to findings of temporal stability in overall risk aversion. However, that stability is around different levels of risk aversion than one might naively infer without the controls for sample selection and attrition we are able to implement. This evidence of “randomization bias” from sample selection...

  4. UNLABELED SELECTED SAMPLES IN FEATURE EXTRACTION FOR CLASSIFICATION OF HYPERSPECTRAL IMAGES WITH LIMITED TRAINING SAMPLES

    Directory of Open Access Journals (Sweden)

    A. Kianisarkaleh

    2015-12-01

    Full Text Available Feature extraction plays a key role in hyperspectral images classification. Using unlabeled samples, often unlimitedly available, unsupervised and semisupervised feature extraction methods show better performance when limited number of training samples exists. This paper illustrates the importance of selecting appropriate unlabeled samples that used in feature extraction methods. Also proposes a new method for unlabeled samples selection using spectral and spatial information. The proposed method has four parts including: PCA, prior classification, posterior classification and sample selection. As hyperspectral image passes these parts, selected unlabeled samples can be used in arbitrary feature extraction methods. The effectiveness of the proposed unlabeled selected samples in unsupervised and semisupervised feature extraction is demonstrated using two real hyperspectral datasets. Results show that through selecting appropriate unlabeled samples, the proposed method can improve the performance of feature extraction methods and increase classification accuracy.

  5. Sample size estimation and sampling techniques for selecting a representative sample

    Directory of Open Access Journals (Sweden)

    Aamir Omair

    2014-01-01

    Full Text Available Introduction: The purpose of this article is to provide a general understanding of the concepts of sampling as applied to health-related research. Sample Size Estimation: It is important to select a representative sample in quantitative research in order to be able to generalize the results to the target population. The sample should be of the required sample size and must be selected using an appropriate probability sampling technique. There are many hidden biases which can adversely affect the outcome of the study. Important factors to consider for estimating the sample size include the size of the study population, confidence level, expected proportion of the outcome variable (for categorical variables/standard deviation of the outcome variable (for numerical variables, and the required precision (margin of accuracy from the study. The more the precision required, the greater is the required sample size. Sampling Techniques: The probability sampling techniques applied for health related research include simple random sampling, systematic random sampling, stratified random sampling, cluster sampling, and multistage sampling. These are more recommended than the nonprobability sampling techniques, because the results of the study can be generalized to the target population.

  6. 40 CFR 89.507 - Sample selection.

    Science.gov (United States)

    2010-07-01

    ... Auditing § 89.507 Sample selection. (a) Engines comprising a test sample will be selected at the location...). However, once the manufacturer ships any test engine, it relinquishes the prerogative to conduct retests...

  7. 40 CFR 90.507 - Sample selection.

    Science.gov (United States)

    2010-07-01

    ... Auditing § 90.507 Sample selection. (a) Engines comprising a test sample will be selected at the location... manufacturer ships any test engine, it relinquishes the prerogative to conduct retests as provided in § 90.508...

  8. A large sample of Kohonen-selected SDSS quasars with weak emission lines: selection effects and statistical properties

    Science.gov (United States)

    Meusinger, H.; Balafkan, N.

    2014-08-01

    Aims: A tiny fraction of the quasar population shows remarkably weak emission lines. Several hypotheses have been developed, but the weak line quasar (WLQ) phenomenon still remains puzzling. The aim of this study was to create a sizeable sample of WLQs and WLQ-like objects and to evaluate various properties of this sample. Methods: We performed a search for WLQs in the spectroscopic data from the Sloan Digital Sky Survey Data Release 7 based on Kohonen self-organising maps for nearly 105 quasar spectra. The final sample consists of 365 quasars in the redshift range z = 0.6 - 4.2 (z¯ = 1.50 ± 0.45) and includes in particular a subsample of 46 WLQs with equivalent widths WMg iiattention was paid to selection effects. Results: The WLQs have, on average, significantly higher luminosities, Eddington ratios, and accretion rates. About half of the excess comes from a selection bias, but an intrinsic excess remains probably caused primarily by higher accretion rates. The spectral energy distribution shows a bluer continuum at rest-frame wavelengths ≳1500 Å. The variability in the optical and UV is relatively low, even taking the variability-luminosity anti-correlation into account. The percentage of radio detected quasars and of core-dominant radio sources is significantly higher than for the control sample, whereas the mean radio-loudness is lower. Conclusions: The properties of our WLQ sample can be consistently understood assuming that it consists of a mix of quasars at the beginning of a stage of increased accretion activity and of beamed radio-quiet quasars. The higher luminosities and Eddington ratios in combination with a bluer spectral energy distribution can be explained by hotter continua, i.e. higher accretion rates. If quasar activity consists of subphases with different accretion rates, a change towards a higher rate is probably accompanied by an only slow development of the broad line region. The composite WLQ spectrum can be reasonably matched by the

  9. Sample Selection for Training Cascade Detectors.

    Science.gov (United States)

    Vállez, Noelia; Deniz, Oscar; Bueno, Gloria

    2015-01-01

    Automatic detection systems usually require large and representative training datasets in order to obtain good detection and false positive rates. Training datasets are such that the positive set has few samples and/or the negative set should represent anything except the object of interest. In this respect, the negative set typically contains orders of magnitude more images than the positive set. However, imbalanced training databases lead to biased classifiers. In this paper, we focus our attention on a negative sample selection method to properly balance the training data for cascade detectors. The method is based on the selection of the most informative false positive samples generated in one stage to feed the next stage. The results show that the proposed cascade detector with sample selection obtains on average better partial AUC and smaller standard deviation than the other compared cascade detectors.

  10. Sample Selection for Training Cascade Detectors.

    Directory of Open Access Journals (Sweden)

    Noelia Vállez

    Full Text Available Automatic detection systems usually require large and representative training datasets in order to obtain good detection and false positive rates. Training datasets are such that the positive set has few samples and/or the negative set should represent anything except the object of interest. In this respect, the negative set typically contains orders of magnitude more images than the positive set. However, imbalanced training databases lead to biased classifiers. In this paper, we focus our attention on a negative sample selection method to properly balance the training data for cascade detectors. The method is based on the selection of the most informative false positive samples generated in one stage to feed the next stage. The results show that the proposed cascade detector with sample selection obtains on average better partial AUC and smaller standard deviation than the other compared cascade detectors.

  11. Selection bias and the Rubin-Ford effect

    International Nuclear Information System (INIS)

    James, P.A.; Joseph, R.D.; Collins, C.A.

    1991-01-01

    We have re-examined the 'Rubin-Ford effect', and more recent claims of galaxy streaming from the same galaxy sample, to investigate the impact of selection effects on these results. A 'Monte Carlo'-type analysis was applied to simulate the selection procedure used to obtain this sample, and a strong bias was identified, resulting in apparent velocity flows at 600-800 km s -1 . Thus the 'Rubin-Ford effect' and the associated galaxy streaming are spurious effects resulting from the method of sample selection. (author)

  12. A novel heterogeneous training sample selection method on space-time adaptive processing

    Science.gov (United States)

    Wang, Qiang; Zhang, Yongshun; Guo, Yiduo

    2018-04-01

    The performance of ground target detection about space-time adaptive processing (STAP) decreases when non-homogeneity of clutter power is caused because of training samples contaminated by target-like signals. In order to solve this problem, a novel nonhomogeneous training sample selection method based on sample similarity is proposed, which converts the training sample selection into a convex optimization problem. Firstly, the existing deficiencies on the sample selection using generalized inner product (GIP) are analyzed. Secondly, the similarities of different training samples are obtained by calculating mean-hausdorff distance so as to reject the contaminated training samples. Thirdly, cell under test (CUT) and the residual training samples are projected into the orthogonal subspace of the target in the CUT, and mean-hausdorff distances between the projected CUT and training samples are calculated. Fourthly, the distances are sorted in order of value and the training samples which have the bigger value are selective preference to realize the reduced-dimension. Finally, simulation results with Mountain-Top data verify the effectiveness of the proposed method.

  13. Antimicrobial and antibiofilm effects of selected food preservatives against Salmonella spp. isolated from chicken samples.

    Science.gov (United States)

    Er, Buket; Demirhan, Burak; Onurdag, Fatma Kaynak; Ozgacar, Selda Özgen; Oktem, Aysel Bayhan

    2014-03-01

    Salmonella spp. are widespread foodborne pathogens that contaminate egg and poultry meats. Attachment, colonization, as well as biofilm formation capacity of Salmonella spp. on food and contact surfaces of food may cause continuous contamination. Biofilm may play a crucial role in the survival of salmonellae under unfavorable environmental conditions, such as in animal slaughterhouses and processing plants. This could serve as a reservoir compromising food safety and human health. Addition of antimicrobial preservatives extends shelf lives of food products, but even when products are supplemented with adequate amounts of preservatives, it is not always possible to inhibit the microorganisms in a biofilm community. In this study, our aims were i) to determine the minimum inhibitory concentrations (MIC) and minimum biofilm inhibitory concentrations (MBIC) of selected preservatives against planktonic and biofilm forms of Salmonella spp. isolated from chicken samples and Salmonella Typhimurium SL1344 standard strain, ii) to show the differences in the susceptibility patterns of same strains versus the planktonic and biofilm forms to the same preservative agent, and iii) to determine and compare antimicrobial and antibiofilm effects of selected food preservatives against Salmonella spp. For this purpose, Salmonella Typhimurium SL1344 standard strain and 4 Salmonella spp. strains isolated from chicken samples were used. Investigation of antimicrobial and antibiofilm effects of selected food preservatives against Salmonella spp. was done according to Clinical and Laboratory Standards Institute M100-S18 guidelines and BioTimer assay, respectively. As preservative agents, pure ciprofloxacin, sodium nitrite, potassium sorbate, sodium benzoate, methyl paraben, and propyl paraben were selected. As a result, it was determined that MBIC values are greater than the MIC values of the preservatives. This result verified the resistance seen in a biofilm community to food

  14. Effects of soil water saturation on sampling equilibrium and kinetics of selected polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Kim, Pil-Gon; Roh, Ji-Yeon; Hong, Yongseok; Kwon, Jung-Hwan

    2017-10-01

    Passive sampling can be applied for measuring the freely dissolved concentration of hydrophobic organic chemicals (HOCs) in soil pore water. When using passive samplers under field conditions, however, there are factors that might affect passive sampling equilibrium and kinetics, such as soil water saturation. To determine the effects of soil water saturation on passive sampling, the equilibrium and kinetics of passive sampling were evaluated by observing changes in the distribution coefficient between sampler and soil (K sampler/soil ) and the uptake rate constant (k u ) at various soil water saturations. Polydimethylsiloxane (PDMS) passive samplers were deployed into artificial soils spiked with seven selected polycyclic aromatic hydrocarbons (PAHs). In dry soil (0% water saturation), both K sampler/soil and k u values were much lower than those in wet soils likely due to the contribution of adsorption of PAHs onto soil mineral surfaces and the conformational changes in soil organic matter. For high molecular weight PAHs (chrysene, benzo[a]pyrene, and dibenzo[a,h]anthracene), both K sampler/soil and k u values increased with increasing soil water saturation, whereas they decreased with increasing soil water saturation for low molecular weight PAHs (phenanthrene, anthracene, fluoranthene, and pyrene). Changes in the sorption capacity of soil organic matter with soil water content would be the main cause of the changes in passive sampling equilibrium. Henry's law constant could explain the different behaviors in uptake kinetics of the selected PAHs. The results of this study would be helpful when passive samplers are deployed under various soil water saturations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Robust inference in sample selection models

    KAUST Repository

    Zhelonkin, Mikhail; Genton, Marc G.; Ronchetti, Elvezio

    2015-01-01

    The problem of non-random sample selectivity often occurs in practice in many fields. The classical estimators introduced by Heckman are the backbone of the standard statistical analysis of these models. However, these estimators are very sensitive to small deviations from the distributional assumptions which are often not satisfied in practice. We develop a general framework to study the robustness properties of estimators and tests in sample selection models. We derive the influence function and the change-of-variance function of Heckman's two-stage estimator, and we demonstrate the non-robustness of this estimator and its estimated variance to small deviations from the model assumed. We propose a procedure for robustifying the estimator, prove its asymptotic normality and give its asymptotic variance. Both cases with and without an exclusion restriction are covered. This allows us to construct a simple robust alternative to the sample selection bias test. We illustrate the use of our new methodology in an analysis of ambulatory expenditures and we compare the performance of the classical and robust methods in a Monte Carlo simulation study.

  16. Robust inference in sample selection models

    KAUST Repository

    Zhelonkin, Mikhail

    2015-11-20

    The problem of non-random sample selectivity often occurs in practice in many fields. The classical estimators introduced by Heckman are the backbone of the standard statistical analysis of these models. However, these estimators are very sensitive to small deviations from the distributional assumptions which are often not satisfied in practice. We develop a general framework to study the robustness properties of estimators and tests in sample selection models. We derive the influence function and the change-of-variance function of Heckman\\'s two-stage estimator, and we demonstrate the non-robustness of this estimator and its estimated variance to small deviations from the model assumed. We propose a procedure for robustifying the estimator, prove its asymptotic normality and give its asymptotic variance. Both cases with and without an exclusion restriction are covered. This allows us to construct a simple robust alternative to the sample selection bias test. We illustrate the use of our new methodology in an analysis of ambulatory expenditures and we compare the performance of the classical and robust methods in a Monte Carlo simulation study.

  17. Woody species diversity in forest plantations in a mountainous region of Beijing, China: effects of sampling scale and species selection.

    Directory of Open Access Journals (Sweden)

    Yuxin Zhang

    Full Text Available The role of forest plantations in biodiversity conservation has gained more attention in recent years. However, most work on evaluating the diversity of forest plantations focuses only on one spatial scale; thus, we examined the effects of sampling scale on diversity in forest plantations. We designed a hierarchical sampling strategy to collect data on woody species diversity in planted pine (Pinus tabuliformis Carr., planted larch (Larix principis-rupprechtii Mayr., and natural secondary deciduous broadleaf forests in a mountainous region of Beijing, China. Additive diversity partition analysis showed that, compared to natural forests, the planted pine forests had a different woody species diversity partitioning pattern at multi-scales (except the Simpson diversity in the regeneration layer, while the larch plantations did not show multi-scale diversity partitioning patterns that were obviously different from those in the natural secondary broadleaf forest. Compare to the natural secondary broadleaf forests, the effects of planted pine forests on woody species diversity are dependent on the sampling scale and layers selected for analysis. Diversity in the planted larch forest, however, was not significantly different from that in the natural forest for all diversity components at all sampling levels. Our work demonstrated that the species selected for afforestation and the sampling scales selected for data analysis alter the conclusions on the levels of diversity supported by plantations. We suggest that a wide range of scales should be considered in the evaluation of the role of forest plantations on biodiversity conservation.

  18. Assessing the joint effect of population stratification and sample selection in studies of gene-gene (environment interactions

    Directory of Open Access Journals (Sweden)

    Cheng KF

    2012-01-01

    Full Text Available Abstract Background It is well known that the presence of population stratification (PS may cause the usual test in case-control studies to produce spurious gene-disease associations. However, the impact of the PS and sample selection (SS is less known. In this paper, we provide a systematic study of the joint effect of PS and SS under a more general risk model containing genetic and environmental factors. We provide simulation results to show the magnitude of the bias and its impact on type I error rate of the usual chi-square test under a wide range of PS level and selection bias. Results The biases to the estimation of main and interaction effect are quantified and then their bounds derived. The estimated bounds can be used to compute conservative p-values for the association test. If the conservative p-value is smaller than the significance level, we can safely claim that the association test is significant regardless of the presence of PS or not, or if there is any selection bias. We also identify conditions for the null bias. The bias depends on the allele frequencies, exposure rates, gene-environment odds ratios and disease risks across subpopulations and the sampling of the cases and controls. Conclusion Our results show that the bias cannot be ignored even the case and control data were matched in ethnicity. A real example is given to illustrate application of the conservative p-value. These results are useful to the genetic association studies of main and interaction effects.

  19. 40 CFR 205.171-3 - Test motorcycle sample selection.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test motorcycle sample selection. 205... ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycle Exhaust Systems § 205.171-3 Test motorcycle sample selection. A test motorcycle to be used for selective enforcement audit testing...

  20. Effects of state and trait anxiety on selective attention to threatening stimuli in a non-clinical sample of school children

    Directory of Open Access Journals (Sweden)

    Jeniffer Ortega Marín

    2015-01-01

    Full Text Available Attentional biases, consisting of a preferential processing of threatening stimuli, have been found in anxious adults as predicted by several cognitive models. However, studies with non-clinical samples of children have provided mixed results. therefore, the aim of this research was to determine the effects of state and trait anxiety on the selective attention towards threatening stimuli in a non-clinical sample of school children (age: 8 to 13, n = 110 using the dot-probe task. This study did not reveal an effect of trait anxiety on selective attention towards threatening stimuli. However, a significant difference was found between participants with low state anxiety and high state anxiety. Nevertheless, the effect size was small. Specifically, participants with low state anxiety showed a bias towards threatening stimuli. Overall, the findings of this research with a non-clinical sample of school children suggest that attentional biases towards threatening information, which has been repeatedly found in anxious adults, are not necessarily inherent to non-clinical anxiety in children and on the other hand, the relationship between attentional biases and anxiety in this population might be moderated by other cognitive processes.

  1. The Atacama Cosmology Telescope: Physical Properties and Purity of a Galaxy Cluster Sample Selected Via the Sunyaev-Zel'Dovich Effect

    Science.gov (United States)

    Menanteau, Felipe; Gonzalez, Jorge; Juin, Jean-Baptiste; Marriage, Tobias; Reese, Erik D.; Acquaviva, Viviana; Aguirre, Paula; Appel, John Willam; Baker, Andrew J.; Barrientos, L. Felipe; hide

    2010-01-01

    We present optical and X-ray properties for the first confirmed galaxy cluster sample selected by the Sunyaev-Zel'dovich Effect from 148 GHz maps over 455 square degrees of sky made with the Atacama Cosmology Telescope. These maps. coupled with multi-band imaging on 4-meter-class optical telescopes, have yielded a sample of 23 galaxy clusters with redshifts between 0.118 and 1.066. Of these 23 clusters, 10 are newly discovered. The selection of this sample is approximately mass limited and essentially independent of redshift. We provide optical positions, images, redshifts and X-ray fluxes and luminosities for the full sample, and X-ray temperatures of an important subset. The mass limit of the full sample is around 8.0 x 10(exp 14) Stellar Mass. with a number distribution that peaks around a redshift of 0.4. For the 10 highest significance SZE-selected cluster candidates, all of which are optically confirmed, the mass threshold is 1 x 10(exp 15) Stellar Mass and the redshift range is 0.167 to 1.066. Archival observations from Chandra, XMM-Newton. and ROSAT provide X-ray luminosities and temperatures that are broadly consistent with this mass threshold. Our optical follow-up procedure also allowed us to assess the purity of the ACT cluster sample. Eighty (one hundred) percent of the 148 GHz candidates with signal-to-noise ratios greater than 5.1 (5.7) are confirmed as massive clusters. The reported sample represents one of the largest SZE-selected sample of massive clusters over all redshifts within a cosmologically-significant survey volume, which will enable cosmological studies as well as future studies on the evolution, morphology, and stellar populations in the most massive clusters in the Universe.

  2. Effect of selective logging on genetic diversity and gene flow in Cariniana legalis sampled from a cacao agroforestry system.

    Science.gov (United States)

    Leal, J B; Santos, R P; Gaiotto, F A

    2014-01-28

    The fragments of the Atlantic Forest of southern Bahia have a long history of intense logging and selective cutting. Some tree species, such as jequitibá rosa (Cariniana legalis), have experienced a reduction in their populations with respect to both area and density. To evaluate the possible effects of selective logging on genetic diversity, gene flow, and spatial genetic structure, 51 C. legalis individuals were sampled, representing the total remaining population from the cacao agroforestry system. A total of 120 alleles were observed from the 11 microsatellite loci analyzed. The average observed heterozygosity (0.486) was less than the expected heterozygosity (0.721), indicating a loss of genetic diversity in this population. A high fixation index (FIS = 0.325) was found, which is possibly due to a reduction in population size, resulting in increased mating among relatives. The maximum (1055 m) and minimum (0.095 m) distances traveled by pollen or seeds were inferred based on paternity tests. We found 36.84% of unique parents among all sampled seedlings. The progenitors of the remaining seedlings (63.16%) were most likely out of the sampled area. Positive and significant spatial genetic structure was identified in this population among classes 10 to 30 m away with an average coancestry coefficient between pairs of individuals of 0.12. These results suggest that the agroforestry system of cacao cultivation is contributing to maintaining levels of diversity and gene flow in the studied population, thus minimizing the effects of selective logging.

  3. The genealogy of samples in models with selection.

    Science.gov (United States)

    Neuhauser, C; Krone, S M

    1997-02-01

    We introduce the genealogy of a random sample of genes taken from a large haploid population that evolves according to random reproduction with selection and mutation. Without selection, the genealogy is described by Kingman's well-known coalescent process. In the selective case, the genealogy of the sample is embedded in a graph with a coalescing and branching structure. We describe this graph, called the ancestral selection graph, and point out differences and similarities with Kingman's coalescent. We present simulations for a two-allele model with symmetric mutation in which one of the alleles has a selective advantage over the other. We find that when the allele frequencies in the population are already in equilibrium, then the genealogy does not differ much from the neutral case. This is supported by rigorous results. Furthermore, we describe the ancestral selection graph for other selective models with finitely many selection classes, such as the K-allele models, infinitely-many-alleles models. DNA sequence models, and infinitely-many-sites models, and briefly discuss the diploid case.

  4. 40 CFR 205.160-2 - Test sample selection and preparation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test sample selection and preparation... sample selection and preparation. (a) Vehicles comprising the sample which are required to be tested... maintained in any manner unless such preparation, tests, modifications, adjustments or maintenance are part...

  5. Principal Stratification in sample selection problems with non normal error terms

    DEFF Research Database (Denmark)

    Rocci, Roberto; Mellace, Giovanni

    The aim of the paper is to relax distributional assumptions on the error terms, often imposed in parametric sample selection models to estimate causal effects, when plausible exclusion restrictions are not available. Within the principal stratification framework, we approximate the true distribut...... an application to the Job Corps training program....

  6. The quasar luminosity function from a variability-selected sample

    Science.gov (United States)

    Hawkins, M. R. S.; Veron, P.

    1993-01-01

    A sample of quasars is selected from a 10-yr sequence of 30 UK Schmidt plates. Luminosity functions are derived in several redshift intervals, which in each case show a featureless power-law rise towards low luminosities. There is no sign of the 'break' found in the recent UVX sample of Boyle et al. It is suggested that reasons for the disagreement are connected with biases in the selection of the UVX sample. The question of the nature of quasar evolution appears to be still unresolved.

  7. On a Robust MaxEnt Process Regression Model with Sample-Selection

    Directory of Open Access Journals (Sweden)

    Hea-Jung Kim

    2018-04-01

    Full Text Available In a regression analysis, a sample-selection bias arises when a dependent variable is partially observed as a result of the sample selection. This study introduces a Maximum Entropy (MaxEnt process regression model that assumes a MaxEnt prior distribution for its nonparametric regression function and finds that the MaxEnt process regression model includes the well-known Gaussian process regression (GPR model as a special case. Then, this special MaxEnt process regression model, i.e., the GPR model, is generalized to obtain a robust sample-selection Gaussian process regression (RSGPR model that deals with non-normal data in the sample selection. Various properties of the RSGPR model are established, including the stochastic representation, distributional hierarchy, and magnitude of the sample-selection bias. These properties are used in the paper to develop a hierarchical Bayesian methodology to estimate the model. This involves a simple and computationally feasible Markov chain Monte Carlo algorithm that avoids analytical or numerical derivatives of the log-likelihood function of the model. The performance of the RSGPR model in terms of the sample-selection bias correction, robustness to non-normality, and prediction, is demonstrated through results in simulations that attest to its good finite-sample performance.

  8. HOT-DUST-POOR QUASARS IN MID-INFRARED AND OPTICALLY SELECTED SAMPLES

    International Nuclear Information System (INIS)

    Hao Heng; Elvis, Martin; Civano, Francesca; Lawrence, Andy

    2011-01-01

    We show that the hot-dust-poor (HDP) quasars, originally found in the X-ray-selected XMM-COSMOS type 1 active galactic nucleus (AGN) sample, are just as common in two samples selected at optical/infrared wavelengths: the Richards et al. Spitzer/SDSS sample (8.7% ± 2.2%) and the Palomar-Green-quasar-dominated sample of Elvis et al. (9.5% ± 5.0%). The properties of the HDP quasars in these two samples are consistent with the XMM-COSMOS sample, except that, at the 99% (∼ 2.5σ) significance, a larger proportion of the HDP quasars in the Spitzer/SDSS sample have weak host galaxy contributions, probably due to the selection criteria used. Either the host dust is destroyed (dynamically or by radiation) or is offset from the central black hole due to recoiling. Alternatively, the universality of HDP quasars in samples with different selection methods and the continuous distribution of dust covering factor in type 1 AGNs suggest that the range of spectral energy distributions could be related to the range of tilts in warped fueling disks, as in the model of Lawrence and Elvis, with HDP quasars having relatively small warps.

  9. The Impact of Selection, Gene Conversion, and Biased Sampling on the Assessment of Microbial Demography.

    Science.gov (United States)

    Lapierre, Marguerite; Blin, Camille; Lambert, Amaury; Achaz, Guillaume; Rocha, Eduardo P C

    2016-07-01

    Recent studies have linked demographic changes and epidemiological patterns in bacterial populations using coalescent-based approaches. We identified 26 studies using skyline plots and found that 21 inferred overall population expansion. This surprising result led us to analyze the impact of natural selection, recombination (gene conversion), and sampling biases on demographic inference using skyline plots and site frequency spectra (SFS). Forward simulations based on biologically relevant parameters from Escherichia coli populations showed that theoretical arguments on the detrimental impact of recombination and especially natural selection on the reconstructed genealogies cannot be ignored in practice. In fact, both processes systematically lead to spurious interpretations of population expansion in skyline plots (and in SFS for selection). Weak purifying selection, and especially positive selection, had important effects on skyline plots, showing patterns akin to those of population expansions. State-of-the-art techniques to remove recombination further amplified these biases. We simulated three common sampling biases in microbiological research: uniform, clustered, and mixed sampling. Alone, or together with recombination and selection, they further mislead demographic inferences producing almost any possible skyline shape or SFS. Interestingly, sampling sub-populations also affected skyline plots and SFS, because the coalescent rates of populations and their sub-populations had different distributions. This study suggests that extreme caution is needed to infer demographic changes solely based on reconstructed genealogies. We suggest that the development of novel sampling strategies and the joint analyzes of diverse population genetic methods are strictly necessary to estimate demographic changes in populations where selection, recombination, and biased sampling are present. © The Author 2016. Published by Oxford University Press on behalf of the Society for

  10. 6. Label-free selective plane illumination microscopy of tissue samples

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    Muteb Alharbi

    2017-10-01

    Conclusion: Overall this method meets the demands of the current needs for 3D imaging tissue samples in a label-free manner. Label-free Selective Plane Microscopy directly provides excellent information about the structure of the tissue samples. This work has highlighted the superiority of Label-free Selective Plane Microscopy to current approaches to label-free 3D imaging of tissue.

  11. Using maximum entropy modeling for optimal selection of sampling sites for monitoring networks

    Science.gov (United States)

    Stohlgren, Thomas J.; Kumar, Sunil; Barnett, David T.; Evangelista, Paul H.

    2011-01-01

    Environmental monitoring programs must efficiently describe state shifts. We propose using maximum entropy modeling to select dissimilar sampling sites to capture environmental variability at low cost, and demonstrate a specific application: sample site selection for the Central Plains domain (453,490 km2) of the National Ecological Observatory Network (NEON). We relied on four environmental factors: mean annual temperature and precipitation, elevation, and vegetation type. A “sample site” was defined as a 20 km × 20 km area (equal to NEON’s airborne observation platform [AOP] footprint), within which each 1 km2 cell was evaluated for each environmental factor. After each model run, the most environmentally dissimilar site was selected from all potential sample sites. The iterative selection of eight sites captured approximately 80% of the environmental envelope of the domain, an improvement over stratified random sampling and simple random designs for sample site selection. This approach can be widely used for cost-efficient selection of survey and monitoring sites.

  12. Patch-based visual tracking with online representative sample selection

    Science.gov (United States)

    Ou, Weihua; Yuan, Di; Li, Donghao; Liu, Bin; Xia, Daoxun; Zeng, Wu

    2017-05-01

    Occlusion is one of the most challenging problems in visual object tracking. Recently, a lot of discriminative methods have been proposed to deal with this problem. For the discriminative methods, it is difficult to select the representative samples for the target template updating. In general, the holistic bounding boxes that contain tracked results are selected as the positive samples. However, when the objects are occluded, this simple strategy easily introduces the noises into the training data set and the target template and then leads the tracker to drift away from the target seriously. To address this problem, we propose a robust patch-based visual tracker with online representative sample selection. Different from previous works, we divide the object and the candidates into several patches uniformly and propose a score function to calculate the score of each patch independently. Then, the average score is adopted to determine the optimal candidate. Finally, we utilize the non-negative least square method to find the representative samples, which are used to update the target template. The experimental results on the object tracking benchmark 2013 and on the 13 challenging sequences show that the proposed method is robust to the occlusion and achieves promising results.

  13. Selection of representative calibration sample sets for near-infrared reflectance spectroscopy to predict nitrogen concentration in grasses

    DEFF Research Database (Denmark)

    Shetty, Nisha; Rinnan, Åsmund; Gislum, René

    2012-01-01

    ) algorithm were used and compared. Both Puchwein and CADEX methods provide a calibration set equally distributed in space, and both methods require a minimum prior of knowledge. The samples were also selected randomly using complete random, cultivar random (year fixed), year random (cultivar fixed......) and interaction (cultivar × year fixed) random procedures to see the influence of different factors on sample selection. Puchwein's method performed best with lowest RMSEP followed by CADEX, interaction random, year random, cultivar random and complete random. Out of 118 samples of the complete calibration set...... effectively enhance the cost-effectiveness of NIR spectral analysis by reducing the number of analyzed samples in the calibration set by more than 80%, which substantially reduces the effort of laboratory analyses with no significant loss in prediction accuracy....

  14. Study on the effects of sample selection on spectral reflectance reconstruction based on the algorithm of compressive sensing

    International Nuclear Information System (INIS)

    Zhang, Leihong; Liang, Dong

    2016-01-01

    In order to solve the problem that reconstruction efficiency and precision is not high, in this paper different samples are selected to reconstruct spectral reflectance, and a new kind of spectral reflectance reconstruction method based on the algorithm of compressive sensing is provided. Four different color numbers of matte color cards such as the ColorChecker Color Rendition Chart and Color Checker SG, the copperplate paper spot color card of Panton, and the Munsell colors card are chosen as training samples, the spectral image is reconstructed respectively by the algorithm of compressive sensing and pseudo-inverse and Wiener, and the results are compared. These methods of spectral reconstruction are evaluated by root mean square error and color difference accuracy. The experiments show that the cumulative contribution rate and color difference of the Munsell colors card are better than those of the other three numbers of color cards in the same conditions of reconstruction, and the accuracy of the spectral reconstruction will be affected by the training sample of different numbers of color cards. The key technology of reconstruction means that the uniformity and representation of the training sample selection has important significance upon reconstruction. In this paper, the influence of the sample selection on the spectral image reconstruction is studied. The precision of the spectral reconstruction based on the algorithm of compressive sensing is higher than that of the traditional algorithm of spectral reconstruction. By the MATLAB simulation results, it can be seen that the spectral reconstruction precision and efficiency are affected by the different color numbers of the training sample. (paper)

  15. Data Quality Objectives For Selecting Waste Samples For Bench-Scale Reformer Treatability Studies

    International Nuclear Information System (INIS)

    Banning, D.L.

    2011-01-01

    This document describes the data quality objectives to select archived samples located at the 222-S Laboratory for Bench-Scale Reforming testing. The type, quantity, and quality of the data required to select the samples for Fluid Bed Steam Reformer testing are discussed. In order to maximize the efficiency and minimize the time to treat Hanford tank waste in the Waste Treatment and Immobilization Plant, additional treatment processes may be required. One of the potential treatment processes is the fluidized bed steam reformer. A determination of the adequacy of the fluidized bed steam reformer process to treat Hanford tank waste is required. The initial step in determining the adequacy of the fluidized bed steam reformer process is to select archived waste samples from the 222-S Laboratory that will be used in a bench scale tests. Analyses of the selected samples will be required to confirm the samples meet the shipping requirements and for comparison to the bench scale reformer (BSR) test sample selection requirements.

  16. Population genetics inference for longitudinally-sampled mutants under strong selection.

    Science.gov (United States)

    Lacerda, Miguel; Seoighe, Cathal

    2014-11-01

    Longitudinal allele frequency data are becoming increasingly prevalent. Such samples permit statistical inference of the population genetics parameters that influence the fate of mutant variants. To infer these parameters by maximum likelihood, the mutant frequency is often assumed to evolve according to the Wright-Fisher model. For computational reasons, this discrete model is commonly approximated by a diffusion process that requires the assumption that the forces of natural selection and mutation are weak. This assumption is not always appropriate. For example, mutations that impart drug resistance in pathogens may evolve under strong selective pressure. Here, we present an alternative approximation to the mutant-frequency distribution that does not make any assumptions about the magnitude of selection or mutation and is much more computationally efficient than the standard diffusion approximation. Simulation studies are used to compare the performance of our method to that of the Wright-Fisher and Gaussian diffusion approximations. For large populations, our method is found to provide a much better approximation to the mutant-frequency distribution when selection is strong, while all three methods perform comparably when selection is weak. Importantly, maximum-likelihood estimates of the selection coefficient are severely attenuated when selection is strong under the two diffusion models, but not when our method is used. This is further demonstrated with an application to mutant-frequency data from an experimental study of bacteriophage evolution. We therefore recommend our method for estimating the selection coefficient when the effective population size is too large to utilize the discrete Wright-Fisher model. Copyright © 2014 by the Genetics Society of America.

  17. Selective solid-phase extraction of Ni(II) by an ion-imprinted polymer from water samples

    International Nuclear Information System (INIS)

    Saraji, Mohammad; Yousefi, Hamideh

    2009-01-01

    A new ion-imprinted polymer (IIP) material was synthesized by copolymerization of 4-vinylpyridine as monomer, ethyleneglycoldimethacrylate as crosslinking agent and 2,2'-azobis-sobutyronitrile as initiator in the presence of Ni-dithizone complex. The IIP was used as sorbent in a solid-phase extraction column. The effects of sampling volume, elution conditions, sample pH and sample flow rate on the extraction of Ni ions form water samples were studied. The maximum adsorption capacity and the relative selectivity coefficients of imprinted polymer for Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were calculated. Compared with non-imprinted polymer particles, the IIP had higher selectivity for Ni(II). The relative selectivity factor (α r ) values of Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were 21.6, 54.3, and 22.7, respectively, which are greater than 1. The relative standard deviation of the five replicate determinations of Ni(II) was 3.4%. The detection limit for 150 mL of sample was 1.6 μg L -1 using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace nickel in water samples with satisfactory results.

  18. Robust online tracking via adaptive samples selection with saliency detection

    Science.gov (United States)

    Yan, Jia; Chen, Xi; Zhu, QiuPing

    2013-12-01

    Online tracking has shown to be successful in tracking of previously unknown objects. However, there are two important factors which lead to drift problem of online tracking, the one is how to select the exact labeled samples even when the target locations are inaccurate, and the other is how to handle the confusors which have similar features with the target. In this article, we propose a robust online tracking algorithm with adaptive samples selection based on saliency detection to overcome the drift problem. To deal with the problem of degrading the classifiers using mis-aligned samples, we introduce the saliency detection method to our tracking problem. Saliency maps and the strong classifiers are combined to extract the most correct positive samples. Our approach employs a simple yet saliency detection algorithm based on image spectral residual analysis. Furthermore, instead of using the random patches as the negative samples, we propose a reasonable selection criterion, in which both the saliency confidence and similarity are considered with the benefits that confusors in the surrounding background are incorporated into the classifiers update process before the drift occurs. The tracking task is formulated as a binary classification via online boosting framework. Experiment results in several challenging video sequences demonstrate the accuracy and stability of our tracker.

  19. 40 CFR 205.57-2 - Test vehicle sample selection.

    Science.gov (United States)

    2010-07-01

    ... pursuant to a test request in accordance with this subpart will be selected in the manner specified in the... then using a table of random numbers to select the number of vehicles as specified in paragraph (c) of... with the desig-nated AQL are contained in Appendix I, -Table II. (c) The appropriate batch sample size...

  20. Selection of the Sample for Data-Driven $Z \\to \

    CERN Document Server

    Krauss, Martin

    2009-01-01

    The topic of this study was to improve the selection of the sample for data-driven Z → ν ν background estimation, which is a major contribution in supersymmetric searches in ̄ a no-lepton search mode. The data is based on Z → + − samples using data created with ATLAS simulation software. This method works if two leptons are reconstructed, but using cuts that are typical for SUSY searches reconstruction efficiency for electrons and muons is rather low. For this reason it was tried to enhance the data sample. Therefore events were considered, where only one electron was reconstructed. In this case the invariant mass for the electron and each jet was computed to select the jet with the best match for the Z boson mass as not reconstructed electron. This way the sample can be extended but significantly looses purity because of also reconstructed background events. To improve this method other variables have to be considered which were not available for this study. Applying a similar method to muons using ...

  1. Failure Probability Estimation Using Asymptotic Sampling and Its Dependence upon the Selected Sampling Scheme

    Directory of Open Access Journals (Sweden)

    Martinásková Magdalena

    2017-12-01

    Full Text Available The article examines the use of Asymptotic Sampling (AS for the estimation of failure probability. The AS algorithm requires samples of multidimensional Gaussian random vectors, which may be obtained by many alternative means that influence the performance of the AS method. Several reliability problems (test functions have been selected in order to test AS with various sampling schemes: (i Monte Carlo designs; (ii LHS designs optimized using the Periodic Audze-Eglājs (PAE criterion; (iii designs prepared using Sobol’ sequences. All results are compared with the exact failure probability value.

  2. Application of the Sampling Selection Technique in Approaching Financial Audit

    Directory of Open Access Journals (Sweden)

    Victor Munteanu

    2018-03-01

    Full Text Available In his professional approach, the financial auditor has a wide range of working techniques, including selection techniques. They are applied depending on the nature of the information available to the financial auditor, the manner in which they are presented - paper or electronic format, and, last but not least, the time available. Several techniques are applied, successively or in parallel, to increase the safety of the expressed opinion and to provide the audit report with a solid basis of information. Sampling is used in the phase of control or clarification of the identified error. The main purpose is to corroborate or measure the degree of risk detected following a pertinent analysis. Since the auditor does not have time or means to thoroughly rebuild the information, the sampling technique can provide an effective response to the need for valorization.

  3. 40 CFR 205.171-2 - Test exhaust system sample selection and preparation.

    Science.gov (United States)

    2010-07-01

    ... Systems § 205.171-2 Test exhaust system sample selection and preparation. (a)(1) Exhaust systems... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test exhaust system sample selection and preparation. 205.171-2 Section 205.171-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  4. Selective information sampling

    Directory of Open Access Journals (Sweden)

    Peter A. F. Fraser-Mackenzie

    2009-06-01

    Full Text Available This study investigates the amount and valence of information selected during single item evaluation. One hundred and thirty-five participants evaluated a cell phone by reading hypothetical customers reports. Some participants were first asked to provide a preliminary rating based on a picture of the phone and some technical specifications. The participants who were given the customer reports only after they made a preliminary rating exhibited valence bias in their selection of customers reports. In contrast, the participants that did not make an initial rating sought subsequent information in a more balanced, albeit still selective, manner. The preliminary raters used the least amount of information in their final decision, resulting in faster decision times. The study appears to support the notion that selective exposure is utilized in order to develop cognitive coherence.

  5. Selective parathyroid venous sampling in primary hyperparathyroidism: A systematic review and meta-analysis.

    Science.gov (United States)

    Ibraheem, Kareem; Toraih, Eman A; Haddad, Antoine B; Farag, Mahmoud; Randolph, Gregory W; Kandil, Emad

    2018-05-14

    Minimally invasive parathyroidectomy requires accurate preoperative localization techniques. There is considerable controversy about the effectiveness of selective parathyroid venous sampling (sPVS) in primary hyperparathyroidism (PHPT) patients. The aim of this meta-analysis is to examine the diagnostic accuracy of sPVS as a preoperative localization modality in PHPT. Studies evaluating the diagnostic accuracy of sPVS for PHPT were electronically searched in the PubMed, EMBASE, Web of Science, and Cochrane Controlled Trials Register databases. Two independent authors reviewed the studies, and revised quality assessment of diagnostic accuracy study tool was used for the quality assessment. Study heterogeneity and pooled estimates were calculated. Two hundred and two unique studies were identified. Of those, 12 studies were included in the meta-analysis. Pooled sensitivity, specificity, and positive likelihood ratio (PLR) of sPVS were 74%, 41%, and 1.55, respectively. The area-under-the-receiver operating characteristic curve was 0.684, indicating an average discriminatory ability of sPVS. On comparison between sPVS and noninvasive imaging modalities, sensitivity, PLR, and positive posttest probability were significantly higher in sPVS compared to noninvasive imaging modalities. Interestingly, super-selective venous sampling had the highest sensitivity, accuracy, and positive posttest probability compared to other parathyroid venous sampling techniques. This is the first meta-analysis to examine the accuracy of sPVS in PHPT. sPVS had higher pooled sensitivity when compared to noninvasive modalities in revision parathyroid surgery. However, the invasiveness of this technique does not favor its routine use for preoperative localization. Super-selective venous sampling was the most accurate among all other parathyroid venous sampling techniques. Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

  6. 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)

  7. Application of random effects to the study of resource selection by animals.

    Science.gov (United States)

    Gillies, Cameron S; Hebblewhite, Mark; Nielsen, Scott E; Krawchuk, Meg A; Aldridge, Cameron L; Frair, Jacqueline L; Saher, D Joanne; Stevens, Cameron E; Jerde, Christopher L

    2006-07-01

    1. Resource selection estimated by logistic regression is used increasingly in studies to identify critical resources for animal populations and to predict species occurrence. 2. Most frequently, individual animals are monitored and pooled to estimate population-level effects without regard to group or individual-level variation. Pooling assumes that both observations and their errors are independent, and resource selection is constant given individual variation in resource availability. 3. Although researchers have identified ways to minimize autocorrelation, variation between individuals caused by differences in selection or available resources, including functional responses in resource selection, have not been well addressed. 4. Here we review random-effects models and their application to resource selection modelling to overcome these common limitations. We present a simple case study of an analysis of resource selection by grizzly bears in the foothills of the Canadian Rocky Mountains with and without random effects. 5. Both categorical and continuous variables in the grizzly bear model differed in interpretation, both in statistical significance and coefficient sign, depending on how a random effect was included. We used a simulation approach to clarify the application of random effects under three common situations for telemetry studies: (a) discrepancies in sample sizes among individuals; (b) differences among individuals in selection where availability is constant; and (c) differences in availability with and without a functional response in resource selection. 6. We found that random intercepts accounted for unbalanced sample designs, and models with random intercepts and coefficients improved model fit given the variation in selection among individuals and functional responses in selection. Our empirical example and simulations demonstrate how including random effects in resource selection models can aid interpretation and address difficult assumptions

  8. Mineral Composition of Selected Serbian Propolis Samples

    Directory of Open Access Journals (Sweden)

    Tosic Snezana

    2017-06-01

    Full Text Available The aim of this work was to determine the content of 22 macro- and microelements in ten raw Serbian propolis samples which differ in geographical and botanical origin as well as in polluted agent contents by atomic emission spectrometry with inductively coupled plasma (ICP-OES. The macroelements were more common and present Ca content was the highest while Na content the lowest. Among the studied essential trace elements Fe was the most common element. The levels of toxic elements (Pb, Cd, As and Hg were also analyzed, since they were possible environmental contaminants that could be transferred into propolis products for human consumption. As and Hg were not detected in any of the analyzed samples but a high level of Pb (2.0-9.7 mg/kg was detected and only selected portions of raw propolis could be used to produce natural medicines and dietary supplements for humans. Obtained results were statistically analyzed, and the examined samples showed a wide range of element content.

  9. Does self-selection affect samples' representativeness in online surveys? An investigation in online video game research.

    Science.gov (United States)

    Khazaal, Yasser; van Singer, Mathias; Chatton, Anne; Achab, Sophia; Zullino, Daniele; Rothen, Stephane; Khan, Riaz; Billieux, Joel; Thorens, Gabriel

    2014-07-07

    The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy. Our objective was to explore the representativeness of a self-selected sample of online gamers using online players' virtual characters (avatars). All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars' characteristics were defined using various games' scores, reported on the WoW's official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars. We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples. Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted.

  10. Obscured AGN at z ~ 1 from the zCOSMOS-Bright Survey. I. Selection and optical properties of a [Ne v]-selected sample

    Science.gov (United States)

    Mignoli, M.; Vignali, C.; Gilli, R.; Comastri, A.; Zamorani, G.; Bolzonella, M.; Bongiorno, A.; Lamareille, F.; Nair, P.; Pozzetti, L.; Lilly, S. J.; Carollo, C. M.; Contini, T.; Kneib, J.-P.; Le Fèvre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Caputi, K.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovač, K.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Pellò, R.; Peng, Y.; Perez Montero, E.; Presotto, V.; Silverman, J. D.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Bordoloi, R.; Cappi, A.; Cimatti, A.; Koekemoer, A. M.; McCracken, H. J.; Moresco, M.; Welikala, N.

    2013-08-01

    Aims: The application of multi-wavelength selection techniques is essential for obtaining a complete and unbiased census of active galactic nuclei (AGN). We present here a method for selecting z ~ 1 obscured AGN from optical spectroscopic surveys. Methods: A sample of 94 narrow-line AGN with 0.65 advantage of the large amount of data available in the COSMOS field, the properties of the [Ne v]-selected type 2 AGN were investigated, focusing on their host galaxies, X-ray emission, and optical line-flux ratios. Finally, a previously developed diagnostic, based on the X-ray-to-[Ne v] luminosity ratio, was exploited to search for the more heavily obscured AGN. Results: We found that [Ne v]-selected narrow-line AGN have Seyfert 2-like optical spectra, although their emission line ratios are diluted by a star-forming component. The ACS morphologies and stellar component in the optical spectra indicate a preference for our type 2 AGN to be hosted in early-type spirals with stellar masses greater than 109.5 - 10 M⊙, on average higher than those of the galaxy parent sample. The fraction of galaxies hosting [Ne v]-selected obscured AGN increases with the stellar mass, reaching a maximum of about 3% at ≈2 × 1011 M⊙. A comparison with other selection techniques at z ~ 1, namely the line-ratio diagnostics and X-ray detections, shows that the detection of the [Ne v] λ3426 line is an effective method for selecting AGN in the optical band, in particular the most heavily obscured ones, but cannot provide a complete census of type 2 AGN by itself. Finally, the high fraction of [Ne v]-selected type 2 AGN not detected in medium-deep (≈100-200 ks) Chandra observations (67%) is suggestive of the inclusion of Compton-thick (i.e., with NH > 1024 cm-2) sources in our sample. The presence of a population of heavily obscured AGN is corroborated by the X-ray-to-[Ne v] ratio; we estimated, by means of an X-ray stacking technique and simulations, that the Compton-thick fraction in our

  11. THE ATACAMA COSMOLOGY TELESCOPE: DYNAMICAL MASSES AND SCALING RELATIONS FOR A SAMPLE OF MASSIVE SUNYAEV-ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTERS ,

    International Nuclear Information System (INIS)

    Sifón, Cristóbal; Barrientos, L. Felipe; González, Jorge; Infante, Leopoldo; Dünner, Rolando; Menanteau, Felipe; Hughes, John P.; Baker, Andrew J.; Hasselfield, Matthew; Marriage, Tobias A.; Crichton, Devin; Gralla, Megan B.; Addison, Graeme E.; Dunkley, Joanna; Battaglia, Nick; Bond, J. Richard; Hajian, Amir; Das, Sudeep; Devlin, Mark J.; Hilton, Matt

    2013-01-01

    We present the first dynamical mass estimates and scaling relations for a sample of Sunyaev-Zel'dovich effect (SZE) selected galaxy clusters. The sample consists of 16 massive clusters detected with the Atacama Cosmology Telescope (ACT) over a 455 deg 2 area of the southern sky. Deep multi-object spectroscopic observations were taken to secure intermediate-resolution (R ∼ 700-800) spectra and redshifts for ≈60 member galaxies on average per cluster. The dynamical masses M 200c of the clusters have been calculated using simulation-based scaling relations between velocity dispersion and mass. The sample has a median redshift z = 0.50 and a median mass M 200c ≅12×10 14 h 70 -1 M sun with a lower limit M 200c ≅6×10 14 h 70 -1 M sun , consistent with the expectations for the ACT southern sky survey. These masses are compared to the ACT SZE properties of the sample, specifically, the match-filtered central SZE amplitude y 0 -tilde, the central Compton parameter y 0 , and the integrated Compton signal Y 200c , which we use to derive SZE-mass scaling relations. All SZE estimators correlate with dynamical mass with low intrinsic scatter (∼< 20%), in agreement with numerical simulations. We explore the effects of various systematic effects on these scaling relations, including the correlation between observables and the influence of dynamically disturbed clusters. Using the three-dimensional information available, we divide the sample into relaxed and disturbed clusters and find that ∼50% of the clusters are disturbed. There are hints that disturbed systems might bias the scaling relations, but given the current sample sizes, these differences are not significant; further studies including more clusters are required to assess the impact of these clusters on the scaling relations

  12. 40 CFR 761.247 - Sample site selection for pipe segment removal.

    Science.gov (United States)

    2010-07-01

    ... end of the pipe segment. (3) If the pipe segment is cut with a saw or other mechanical device, take..., take samples from a total of seven segments. (A) Sample the first and last segments removed. (B) Select... total length for purposes of disposal, take samples of each segment that is 1/2 mile distant from the...

  13. Adoption of selected innovations in rice production and their effect ...

    African Journals Online (AJOL)

    Adoption of selected innovations in rice production and their effect on farmers living standard in Bauchi local government area, Bauchi state, Nigeria. ... International Journal of Natural and Applied Sciences ... Simple random sampling technique was used for the selection of 82 rice growers from these villages. The data ...

  14. Hybrid nested sampling algorithm for Bayesian model selection applied to inverse subsurface flow problems

    International Nuclear Information System (INIS)

    Elsheikh, Ahmed H.; Wheeler, Mary F.; Hoteit, Ibrahim

    2014-01-01

    A Hybrid Nested Sampling (HNS) algorithm is proposed for efficient Bayesian model calibration and prior model selection. The proposed algorithm combines, Nested Sampling (NS) algorithm, Hybrid Monte Carlo (HMC) sampling and gradient estimation using Stochastic Ensemble Method (SEM). NS is an efficient sampling algorithm that can be used for Bayesian calibration and estimating the Bayesian evidence for prior model selection. Nested sampling has the advantage of computational feasibility. Within the nested sampling algorithm, a constrained sampling step is performed. For this step, we utilize HMC to reduce the correlation between successive sampled states. HMC relies on the gradient of the logarithm of the posterior distribution, which we estimate using a stochastic ensemble method based on an ensemble of directional derivatives. SEM only requires forward model runs and the simulator is then used as a black box and no adjoint code is needed. The developed HNS algorithm is successfully applied for Bayesian calibration and prior model selection of several nonlinear subsurface flow problems

  15. Hybrid nested sampling algorithm for Bayesian model selection applied to inverse subsurface flow problems

    Energy Technology Data Exchange (ETDEWEB)

    Elsheikh, Ahmed H., E-mail: aelsheikh@ices.utexas.edu [Institute for Computational Engineering and Sciences (ICES), University of Texas at Austin, TX (United States); Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Wheeler, Mary F. [Institute for Computational Engineering and Sciences (ICES), University of Texas at Austin, TX (United States); Hoteit, Ibrahim [Department of Earth Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia)

    2014-02-01

    A Hybrid Nested Sampling (HNS) algorithm is proposed for efficient Bayesian model calibration and prior model selection. The proposed algorithm combines, Nested Sampling (NS) algorithm, Hybrid Monte Carlo (HMC) sampling and gradient estimation using Stochastic Ensemble Method (SEM). NS is an efficient sampling algorithm that can be used for Bayesian calibration and estimating the Bayesian evidence for prior model selection. Nested sampling has the advantage of computational feasibility. Within the nested sampling algorithm, a constrained sampling step is performed. For this step, we utilize HMC to reduce the correlation between successive sampled states. HMC relies on the gradient of the logarithm of the posterior distribution, which we estimate using a stochastic ensemble method based on an ensemble of directional derivatives. SEM only requires forward model runs and the simulator is then used as a black box and no adjoint code is needed. The developed HNS algorithm is successfully applied for Bayesian calibration and prior model selection of several nonlinear subsurface flow problems.

  16. Hybrid nested sampling algorithm for Bayesian model selection applied to inverse subsurface flow problems

    KAUST Repository

    Elsheikh, Ahmed H.

    2014-02-01

    A Hybrid Nested Sampling (HNS) algorithm is proposed for efficient Bayesian model calibration and prior model selection. The proposed algorithm combines, Nested Sampling (NS) algorithm, Hybrid Monte Carlo (HMC) sampling and gradient estimation using Stochastic Ensemble Method (SEM). NS is an efficient sampling algorithm that can be used for Bayesian calibration and estimating the Bayesian evidence for prior model selection. Nested sampling has the advantage of computational feasibility. Within the nested sampling algorithm, a constrained sampling step is performed. For this step, we utilize HMC to reduce the correlation between successive sampled states. HMC relies on the gradient of the logarithm of the posterior distribution, which we estimate using a stochastic ensemble method based on an ensemble of directional derivatives. SEM only requires forward model runs and the simulator is then used as a black box and no adjoint code is needed. The developed HNS algorithm is successfully applied for Bayesian calibration and prior model selection of several nonlinear subsurface flow problems. © 2013 Elsevier Inc.

  17. Measurement of radioactivity in the environment - Soil - Part 2: Guidance for the selection of the sampling strategy, sampling and pre-treatment of samples

    International Nuclear Information System (INIS)

    2007-01-01

    This part of ISO 18589 specifies the general requirements, based on ISO 11074 and ISO/IEC 17025, for all steps in the planning (desk study and area reconnaissance) of the sampling and the preparation of samples for testing. It includes the selection of the sampling strategy, the outline of the sampling plan, the presentation of general sampling methods and equipment, as well as the methodology of the pre-treatment of samples adapted to the measurements of the activity of radionuclides in soil. This part of ISO 18589 is addressed to the people responsible for determining the radioactivity present in soil for the purpose of radiation protection. It is applicable to soil from gardens, farmland, urban or industrial sites, as well as soil not affected by human activities. This part of ISO 18589 is applicable to all laboratories regardless of the number of personnel or the range of the testing performed. When a laboratory does not undertake one or more of the activities covered by this part of ISO 18589, such as planning, sampling or testing, the corresponding requirements do not apply. Information is provided on scope, normative references, terms and definitions and symbols, principle, sampling strategy, sampling plan, sampling process, pre-treatment of samples and recorded information. Five annexes inform about selection of the sampling strategy according to the objectives and the radiological characterization of the site and sampling areas, diagram of the evolution of the sample characteristics from the sampling site to the laboratory, example of sampling plan for a site divided in three sampling areas, example of a sampling record for a single/composite sample and example for a sample record for a soil profile with soil description. A bibliography is provided

  18. Field-based random sampling without a sampling frame: control selection for a case-control study in rural Africa.

    Science.gov (United States)

    Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E

    2001-01-01

    Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.

  19. Edge Effects in Line Intersect Sampling With

    Science.gov (United States)

    David L. R. Affleck; Timothy G. Gregoire; Harry T. Valentine

    2005-01-01

    Transects consisting of multiple, connected segments with a prescribed configuration are commonly used in ecological applications of line intersect sampling. The transect configuration has implications for the probability with which population elements are selected and for how the selection probabilities can be modified by the boundary of the tract being sampled. As...

  20. Proposal for selecting an ore sample from mining shaft under Kvanefjeld

    International Nuclear Information System (INIS)

    Lund Clausen, F.

    1979-02-01

    Uranium ore recovered from the tunnel under Kvanefjeld (Greenland) will be processed in a pilot plant. Selection of a fully representative ore sample for both the whole area and single local sites is discussed. A FORTRAN program for ore distribution is presented, in order to enable correct sampling. (EG)

  1. HICOSMO - cosmology with a complete sample of galaxy clusters - I. Data analysis, sample selection and luminosity-mass scaling relation

    Science.gov (United States)

    Schellenberger, G.; Reiprich, T. H.

    2017-08-01

    The X-ray regime, where the most massive visible component of galaxy clusters, the intracluster medium, is visible, offers directly measured quantities, like the luminosity, and derived quantities, like the total mass, to characterize these objects. The aim of this project is to analyse a complete sample of galaxy clusters in detail and constrain cosmological parameters, like the matter density, Ωm, or the amplitude of initial density fluctuations, σ8. The purely X-ray flux-limited sample (HIFLUGCS) consists of the 64 X-ray brightest galaxy clusters, which are excellent targets to study the systematic effects, that can bias results. We analysed in total 196 Chandra observations of the 64 HIFLUGCS clusters, with a total exposure time of 7.7 Ms. Here, we present our data analysis procedure (including an automated substructure detection and an energy band optimization for surface brightness profile analysis) that gives individually determined, robust total mass estimates. These masses are tested against dynamical and Planck Sunyaev-Zeldovich (SZ) derived masses of the same clusters, where good overall agreement is found with the dynamical masses. The Planck SZ masses seem to show a mass-dependent bias to our hydrostatic masses; possible biases in this mass-mass comparison are discussed including the Planck selection function. Furthermore, we show the results for the (0.1-2.4) keV luminosity versus mass scaling relation. The overall slope of the sample (1.34) is in agreement with expectations and values from literature. Splitting the sample into galaxy groups and clusters reveals, even after a selection bias correction, that galaxy groups exhibit a significantly steeper slope (1.88) compared to clusters (1.06).

  2. A Uniformly Selected Sample of Low-mass Black Holes in Seyfert 1 Galaxies. II. The SDSS DR7 Sample

    Science.gov (United States)

    Liu, He-Yang; Yuan, Weimin; Dong, Xiao-Bo; Zhou, Hongyan; Liu, Wen-Juan

    2018-04-01

    A new sample of 204 low-mass black holes (LMBHs) in active galactic nuclei (AGNs) is presented with black hole masses in the range of (1–20) × 105 M ⊙. The AGNs are selected through a systematic search among galaxies in the Seventh Data Release (DR7) of the Sloan Digital Sky Survey (SDSS), and careful analyses of their optical spectra and precise measurement of spectral parameters. Combining them with our previous sample selected from SDSS DR4 makes it the largest LMBH sample so far, totaling over 500 objects. Some of the statistical properties of the combined LMBH AGN sample are briefly discussed in the context of exploring the low-mass end of the AGN population. Their X-ray luminosities follow the extension of the previously known correlation with the [O III] luminosity. The effective optical-to-X-ray spectral indices α OX, albeit with a large scatter, are broadly consistent with the extension of the relation with the near-UV luminosity L 2500 Å. Interestingly, a correlation of α OX with black hole mass is also found, with α OX being statistically flatter (stronger X-ray relative to optical) for lower black hole masses. Only 26 objects, mostly radio loud, were detected in radio at 20 cm in the FIRST survey, giving a radio-loud fraction of 4%. The host galaxies of LMBHs have stellar masses in the range of 108.8–1012.4 M ⊙ and optical colors typical of Sbc spirals. They are dominated by young stellar populations that seem to have undergone continuous star formation history.

  3. Towards the harmonization between National Forest Inventory and Forest Condition Monitoring. Consistency of plot allocation and effect of tree selection methods on sample statistics in Italy.

    Science.gov (United States)

    Gasparini, Patrizia; Di Cosmo, Lucio; Cenni, Enrico; Pompei, Enrico; Ferretti, Marco

    2013-07-01

    In the frame of a process aiming at harmonizing National Forest Inventory (NFI) and ICP Forests Level I Forest Condition Monitoring (FCM) in Italy, we investigated (a) the long-term consistency between FCM sample points (a subsample of the first NFI, 1985, NFI_1) and recent forest area estimates (after the second NFI, 2005, NFI_2) and (b) the effect of tree selection method (tree-based or plot-based) on sample composition and defoliation statistics. The two investigations were carried out on 261 and 252 FCM sites, respectively. Results show that some individual forest categories (larch and stone pine, Norway spruce, other coniferous, beech, temperate oaks and cork oak forests) are over-represented and others (hornbeam and hophornbeam, other deciduous broadleaved and holm oak forests) are under-represented in the FCM sample. This is probably due to a change in forest cover, which has increased by 1,559,200 ha from 1985 to 2005. In case of shift from a tree-based to a plot-based selection method, 3,130 (46.7%) of the original 6,703 sample trees will be abandoned, and 1,473 new trees will be selected. The balance between exclusion of former sample trees and inclusion of new ones will be particularly unfavourable for conifers (with only 16.4% of excluded trees replaced by new ones) and less for deciduous broadleaves (with 63.5% of excluded trees replaced). The total number of tree species surveyed will not be impacted, while the number of trees per species will, and the resulting (plot-based) sample composition will have a much larger frequency of deciduous broadleaved trees. The newly selected trees have-in general-smaller diameter at breast height (DBH) and defoliation scores. Given the larger rate of turnover, the deciduous broadleaved part of the sample will be more impacted. Our results suggest that both a revision of FCM network to account for forest area change and a plot-based approach to permit statistical inference and avoid bias in the tree sample

  4. Accounting for animal movement in estimation of resource selection functions: sampling and data analysis.

    Science.gov (United States)

    Forester, James D; Im, Hae Kyung; Rathouz, Paul J

    2009-12-01

    Patterns of resource selection by animal populations emerge as a result of the behavior of many individuals. Statistical models that describe these population-level patterns of habitat use can miss important interactions between individual animals and characteristics of their local environment; however, identifying these interactions is difficult. One approach to this problem is to incorporate models of individual movement into resource selection models. To do this, we propose a model for step selection functions (SSF) that is composed of a resource-independent movement kernel and a resource selection function (RSF). We show that standard case-control logistic regression may be used to fit the SSF; however, the sampling scheme used to generate control points (i.e., the definition of availability) must be accommodated. We used three sampling schemes to analyze simulated movement data and found that ignoring sampling and the resource-independent movement kernel yielded biased estimates of selection. The level of bias depended on the method used to generate control locations, the strength of selection, and the spatial scale of the resource map. Using empirical or parametric methods to sample control locations produced biased estimates under stronger selection; however, we show that the addition of a distance function to the analysis substantially reduced that bias. Assuming a uniform availability within a fixed buffer yielded strongly biased selection estimates that could be corrected by including the distance function but remained inefficient relative to the empirical and parametric sampling methods. As a case study, we used location data collected from elk in Yellowstone National Park, USA, to show that selection and bias may be temporally variable. Because under constant selection the amount of bias depends on the scale at which a resource is distributed in the landscape, we suggest that distance always be included as a covariate in SSF analyses. This approach to

  5. Environment-based selection effects of Planck clusters

    Energy Technology Data Exchange (ETDEWEB)

    Kosyra, R.; Gruen, D.; Seitz, S.; Mana, A.; Rozo, E.; Rykoff, E.; Sanchez, A.; Bender, R.

    2015-07-24

    We investigate whether the large-scale structure environment of galaxy clusters imprints a selection bias on Sunyaev–Zel'dovich (SZ) catalogues. Such a selection effect might be caused by line of sight (LoS) structures that add to the SZ signal or contain point sources that disturb the signal extraction in the SZ survey. We use the Planck PSZ1 union catalogue in the Sloan Digital Sky Survey (SDSS) region as our sample of SZ-selected clusters. We calculate the angular two-point correlation function (2pcf) for physically correlated, foreground and background structure in the RedMaPPer SDSS DR8 catalogue with respect to each cluster. We compare our results with an optically selected comparison cluster sample and with theoretical predictions. In contrast to the hypothesis of no environment-based selection, we find a mean 2pcf for background structures of -0.049 on scales of ≲40 arcmin, significantly non-zero at ~4σ, which means that Planck clusters are more likely to be detected in regions of low background density. We hypothesize this effect arises either from background estimation in the SZ survey or from radio sources in the background. We estimate the defect in SZ signal caused by this effect to be negligibly small, of the order of ~10-4 of the signal of a typical Planck detection. Analogously, there are no implications on X-ray mass measurements. However, the environmental dependence has important consequences for weak lensing follow up of Planck galaxy clusters: we predict that projection effects account for half of the mass contained within a 15 arcmin radius of Planck galaxy clusters. We did not detect a background underdensity of CMASS LRGs, which also leaves a spatially varying redshift dependence of the Planck SZ selection function as a possible cause for our findings.

  6. Evaluation of pump pulsation in respirable size-selective sampling: part II. Changes in sampling efficiency.

    Science.gov (United States)

    Lee, Eun Gyung; Lee, Taekhee; Kim, Seung Won; Lee, Larry; Flemmer, Michael M; Harper, Martin

    2014-01-01

    This second, and concluding, part of this study evaluated changes in sampling efficiency of respirable size-selective samplers due to air pulsations generated by the selected personal sampling pumps characterized in Part I (Lee E, Lee L, Möhlmann C et al. Evaluation of pump pulsation in respirable size-selective sampling: Part I. Pulsation measurements. Ann Occup Hyg 2013). Nine particle sizes of monodisperse ammonium fluorescein (from 1 to 9 μm mass median aerodynamic diameter) were generated individually by a vibrating orifice aerosol generator from dilute solutions of fluorescein in aqueous ammonia and then injected into an environmental chamber. To collect these particles, 10-mm nylon cyclones, also known as Dorr-Oliver (DO) cyclones, were used with five medium volumetric flow rate pumps. Those were the Apex IS, HFS513, GilAir5, Elite5, and Basic5 pumps, which were found in Part I to generate pulsations of 5% (the lowest), 25%, 30%, 56%, and 70% (the highest), respectively. GK2.69 cyclones were used with the Legacy [pump pulsation (PP) = 15%] and Elite12 (PP = 41%) pumps for collection at high flows. The DO cyclone was also used to evaluate changes in sampling efficiency due to pulse shape. The HFS513 pump, which generates a more complex pulse shape, was compared to a single sine wave fluctuation generated by a piston. The luminescent intensity of the fluorescein extracted from each sample was measured with a luminescence spectrometer. Sampling efficiencies were obtained by dividing the intensity of the fluorescein extracted from the filter placed in a cyclone with the intensity obtained from the filter used with a sharp-edged reference sampler. Then, sampling efficiency curves were generated using a sigmoid function with three parameters and each sampling efficiency curve was compared to that of the reference cyclone by constructing bias maps. In general, no change in sampling efficiency (bias under ±10%) was observed until pulsations exceeded 25% for the

  7. A quick method based on SIMPLISMA-KPLS for simultaneously selecting outlier samples and informative samples for model standardization in near infrared spectroscopy

    Science.gov (United States)

    Li, Li-Na; Ma, Chang-Ming; Chang, Ming; Zhang, Ren-Cheng

    2017-12-01

    A novel method based on SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA) and Kernel Partial Least Square (KPLS), named as SIMPLISMA-KPLS, is proposed in this paper for selection of outlier samples and informative samples simultaneously. It is a quick algorithm used to model standardization (or named as model transfer) in near infrared (NIR) spectroscopy. The NIR experiment data of the corn for analysis of the protein content is introduced to evaluate the proposed method. Piecewise direct standardization (PDS) is employed in model transfer. And the comparison of SIMPLISMA-PDS-KPLS and KS-PDS-KPLS is given in this research by discussion of the prediction accuracy of protein content and calculation speed of each algorithm. The conclusions include that SIMPLISMA-KPLS can be utilized as an alternative sample selection method for model transfer. Although it has similar accuracy to Kennard-Stone (KS), it is different from KS as it employs concentration information in selection program. This means that it ensures analyte information is involved in analysis, and the spectra (X) of the selected samples is interrelated with concentration (y). And it can be used for outlier sample elimination simultaneously by validation of calibration. According to the statistical data results of running time, it is clear that the sample selection process is more rapid when using KPLS. The quick algorithm of SIMPLISMA-KPLS is beneficial to improve the speed of online measurement using NIR spectroscopy.

  8. Detection of Salmonella spp. in veterinary samples by combining selective enrichment and real-time PCR.

    Science.gov (United States)

    Goodman, Laura B; McDonough, Patrick L; Anderson, Renee R; Franklin-Guild, Rebecca J; Ryan, James R; Perkins, Gillian A; Thachil, Anil J; Glaser, Amy L; Thompson, Belinda S

    2017-11-01

    Rapid screening for enteric bacterial pathogens in clinical environments is essential for biosecurity. Salmonella found in veterinary hospitals, particularly Salmonella enterica serovar Dublin, can pose unique challenges for culture and testing because of its poor growth. Multiple Salmonella serovars including Dublin are emerging threats to public health given increasing prevalence and antimicrobial resistance. We adapted an automated food testing method to veterinary samples and evaluated the performance of the method in a variety of matrices including environmental samples ( n = 81), tissues ( n = 52), feces ( n = 148), and feed ( n = 29). A commercial kit was chosen as the basis for this approach in view of extensive performance characterizations published by multiple independent organizations. A workflow was established for efficiently and accurately testing veterinary matrices and environmental samples by use of real-time PCR after selective enrichment in Rappaport-Vassiliadis soya (RVS) medium. Using this method, the detection limit for S. Dublin improved by 100-fold over subculture on selective agars (eosin-methylene blue, brilliant green, and xylose-lysine-deoxycholate). Overall, the procedure was effective in detecting Salmonella spp. and provided next-day results.

  9. OBSERVATIONAL SELECTION EFFECTS AND THE M-σ RELATION

    International Nuclear Information System (INIS)

    Gueltekin, Kayhan; Richstone, Douglas O.; Tremaine, Scott; Loeb, Abraham

    2011-01-01

    We examine the possibility that the observed relation between black hole mass and host-galaxy stellar velocity dispersion (the M-σ relation) is biased by an observational selection effect, the difficulty of detecting a black hole whose sphere of influence is smaller than the telescope resolution. In particular, we critically investigate recent claims that the M-σ relation only represents the upper limit to a broad distribution of black hole masses in galaxies of a given velocity dispersion. We find that this hypothesis can be rejected at a high confidence level, at least for the early-type galaxies with relatively high velocity dispersions (median 268 km s -1 ) that comprise most of our sample. We also describe a general procedure for incorporating observational selection effects in estimates of the properties of the M-σ relation. Applying this procedure we find results that are consistent with earlier estimates that did not account for selection effects, although with larger error bars. In particular, (1) the width of the M-σ relation is not significantly increased, (2) the slope and normalization of the M-σ relation are not significantly changed, and (3) most or all luminous early-type galaxies contain central black holes at zero redshift. Our results may not apply to late-type or small galaxies, which are not well represented in our sample.

  10. Selection Component Analysis of Natural Polymorphisms using Population Samples Including Mother-Offspring Combinations, II

    DEFF Research Database (Denmark)

    Jarmer, Hanne Østergaard; Christiansen, Freddy Bugge

    1981-01-01

    Population samples including mother-offspring combinations provide information on the selection components: zygotic selection, sexual selection, gametic seletion and fecundity selection, on the mating pattern, and on the deviation from linkage equilibrium among the loci studied. The theory...

  11. Privacy problems in the small sample selection

    Directory of Open Access Journals (Sweden)

    Loredana Cerbara

    2013-05-01

    Full Text Available The side of social research that uses small samples for the production of micro data, today finds some operating difficulties due to the privacy law. The privacy code is a really important and necessary law because it guarantees the Italian citizen’s rights, as already happens in other Countries of the world. However it does not seem appropriate to limit once more the possibilities of the data production of the national centres of research. That possibilities are already moreover compromised due to insufficient founds is a common problem becoming more and more frequent in the research field. It would be necessary, therefore, to include in the law the possibility to use telephonic lists to select samples useful for activities directly of interest and importance to the citizen, such as the collection of the data carried out on the basis of opinion polls by the centres of research of the Italian CNR and some universities.

  12. Data Quality Objectives For Selecting Waste Samples To Test The Fluid Bed Steam Reformer Test

    International Nuclear Information System (INIS)

    Banning, D.L.

    2010-01-01

    This document describes the data quality objectives to select archived samples located at the 222-S Laboratory for Fluid Bed Steam Reformer testing. The type, quantity and quality of the data required to select the samples for Fluid Bed Steam Reformer testing are discussed. In order to maximize the efficiency and minimize the time to treat Hanford tank waste in the Waste Treatment and Immobilization Plant, additional treatment processes may be required. One of the potential treatment processes is the fluid bed steam reformer (FBSR). A determination of the adequacy of the FBSR process to treat Hanford tank waste is required. The initial step in determining the adequacy of the FBSR process is to select archived waste samples from the 222-S Laboratory that will be used to test the FBSR process. Analyses of the selected samples will be required to confirm the samples meet the testing criteria.

  13. Approaches to sampling and case selection in qualitative research: examples in the geography of health.

    Science.gov (United States)

    Curtis, S; Gesler, W; Smith, G; Washburn, S

    2000-04-01

    This paper focuses on the question of sampling (or selection of cases) in qualitative research. Although the literature includes some very useful discussions of qualitative sampling strategies, the question of sampling often seems to receive less attention in methodological discussion than questions of how data is collected or is analysed. Decisions about sampling are likely to be important in many qualitative studies (although it may not be an issue in some research). There are varying accounts of the principles applicable to sampling or case selection. Those who espouse 'theoretical sampling', based on a 'grounded theory' approach, are in some ways opposed to those who promote forms of 'purposive sampling' suitable for research informed by an existing body of social theory. Diversity also results from the many different methods for drawing purposive samples which are applicable to qualitative research. We explore the value of a framework suggested by Miles and Huberman [Miles, M., Huberman,, A., 1994. Qualitative Data Analysis, Sage, London.], to evaluate the sampling strategies employed in three examples of research by the authors. Our examples comprise three studies which respectively involve selection of: 'healing places'; rural places which incorporated national anti-malarial policies; young male interviewees, identified as either chronically ill or disabled. The examples are used to show how in these three studies the (sometimes conflicting) requirements of the different criteria were resolved, as well as the potential and constraints placed on the research by the selection decisions which were made. We also consider how far the criteria Miles and Huberman suggest seem helpful for planning 'sample' selection in qualitative research.

  14. New sorbent materials for selective extraction of cocaine and benzoylecgonine from human urine samples.

    Science.gov (United States)

    Bujak, Renata; Gadzała-Kopciuch, Renata; Nowaczyk, Alicja; Raczak-Gutknecht, Joanna; Kordalewska, Marta; Struck-Lewicka, Wiktoria; Waszczuk-Jankowska, Małgorzata; Tomczak, Ewa; Kaliszan, Michał; Buszewski, Bogusław; Markuszewski, Michał J

    2016-02-20

    An increase in cocaine consumption has been observed in Europe during the last decade. Benzoylecgonine, as a main urinary metabolite of cocaine in human, is so far the most reliable marker of cocaine consumption. Determination of cocaine and its metabolite in complex biological samples as urine or blood, requires efficient and selective sample pretreatment. In this preliminary study, the newly synthesized sorbent materials were proposed for selective extraction of cocaine and benzoylecgonine from urine samples. Application of these sorbent media allowed to determine cocaine and benzoylecgonine in urine samples at the concentration level of 100ng/ml with good recovery values as 81.7%±6.6 and 73.8%±4.2, respectively. The newly synthesized materials provided efficient, inexpensive and selective extraction of both cocaine and benzoylecgonine from urine samples, which can consequently lead to an increase of the sensitivity of the current available screening diagnostic tests. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Observed Characteristics and Teacher Quality: Impacts of Sample Selection on a Value Added Model

    Science.gov (United States)

    Winters, Marcus A.; Dixon, Bruce L.; Greene, Jay P.

    2012-01-01

    We measure the impact of observed teacher characteristics on student math and reading proficiency using a rich dataset from Florida. We expand upon prior work by accounting directly for nonrandom attrition of teachers from the classroom in a sample selection framework. We find evidence that sample selection is present in the estimation of the…

  16. Nested sampling algorithm for subsurface flow model selection, uncertainty quantification, and nonlinear calibration

    KAUST Repository

    Elsheikh, A. H.

    2013-12-01

    Calibration of subsurface flow models is an essential step for managing ground water aquifers, designing of contaminant remediation plans, and maximizing recovery from hydrocarbon reservoirs. We investigate an efficient sampling algorithm known as nested sampling (NS), which can simultaneously sample the posterior distribution for uncertainty quantification, and estimate the Bayesian evidence for model selection. Model selection statistics, such as the Bayesian evidence, are needed to choose or assign different weights to different models of different levels of complexities. In this work, we report the first successful application of nested sampling for calibration of several nonlinear subsurface flow problems. The estimated Bayesian evidence by the NS algorithm is used to weight different parameterizations of the subsurface flow models (prior model selection). The results of the numerical evaluation implicitly enforced Occam\\'s razor where simpler models with fewer number of parameters are favored over complex models. The proper level of model complexity was automatically determined based on the information content of the calibration data and the data mismatch of the calibrated model.

  17. 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

  18. The partial-reinforcement extinction effect and the contingent-sampling hypothesis.

    Science.gov (United States)

    Hochman, Guy; Erev, Ido

    2013-12-01

    The partial-reinforcement extinction effect (PREE) implies that learning under partial reinforcements is more robust than learning under full reinforcements. While the advantages of partial reinforcements have been well-documented in laboratory studies, field research has failed to support this prediction. In the present study, we aimed to clarify this pattern. Experiment 1 showed that partial reinforcements increase the tendency to select the promoted option during extinction; however, this effect is much smaller than the negative effect of partial reinforcements on the tendency to select the promoted option during the training phase. Experiment 2 demonstrated that the overall effect of partial reinforcements varies inversely with the attractiveness of the alternative to the promoted behavior: The overall effect is negative when the alternative is relatively attractive, and positive when the alternative is relatively unattractive. These results can be captured with a contingent-sampling model assuming that people select options that provided the best payoff in similar past experiences. The best fit was obtained under the assumption that similarity is defined by the sequence of the last four outcomes.

  19. Hybrid nested sampling algorithm for Bayesian model selection applied to inverse subsurface flow problems

    KAUST Repository

    Elsheikh, Ahmed H.; Wheeler, Mary Fanett; Hoteit, Ibrahim

    2014-01-01

    A Hybrid Nested Sampling (HNS) algorithm is proposed for efficient Bayesian model calibration and prior model selection. The proposed algorithm combines, Nested Sampling (NS) algorithm, Hybrid Monte Carlo (HMC) sampling and gradient estimation using

  20. Random selection of items. Selection of n1 samples among N items composing a stratum

    International Nuclear Information System (INIS)

    Jaech, J.L.; Lemaire, R.J.

    1987-02-01

    STR-224 provides generalized procedures to determine required sample sizes, for instance in the course of a Physical Inventory Verification at Bulk Handling Facilities. The present report describes procedures to generate random numbers and select groups of items to be verified in a given stratum through each of the measurement methods involved in the verification. (author). 3 refs

  1. 40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sample selection by random number... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each for...

  2. Frequency-Selective Signal Sensing with Sub-Nyquist Uniform Sampling Scheme

    DEFF Research Database (Denmark)

    Pierzchlewski, Jacek; Arildsen, Thomas

    2015-01-01

    In this paper the authors discuss a problem of acquisition and reconstruction of a signal polluted by adjacent- channel interference. The authors propose a method to find a sub-Nyquist uniform sampling pattern which allows for correct reconstruction of selected frequencies. The method is inspired...... by the Restricted Isometry Property, which is known from the field of compressed sensing. Then, compressed sensing is used to successfully reconstruct a wanted signal even if some of the uniform samples were randomly lost, e. g. due to ADC saturation. An experiment which tests the proposed method in practice...

  3. Imaging a Large Sample with Selective Plane Illumination Microscopy Based on Multiple Fluorescent Microsphere Tracking

    Science.gov (United States)

    Ryu, Inkeon; Kim, Daekeun

    2018-04-01

    A typical selective plane illumination microscopy (SPIM) image size is basically limited by the field of view, which is a characteristic of the objective lens. If an image larger than the imaging area of the sample is to be obtained, image stitching, which combines step-scanned images into a single panoramic image, is required. However, accurately registering the step-scanned images is very difficult because the SPIM system uses a customized sample mount where uncertainties for the translational and the rotational motions exist. In this paper, an image registration technique based on multiple fluorescent microsphere tracking is proposed in the view of quantifying the constellations and measuring the distances between at least two fluorescent microspheres embedded in the sample. Image stitching results are demonstrated for optically cleared large tissue with various staining methods. Compensation for the effect of the sample rotation that occurs during the translational motion in the sample mount is also discussed.

  4. Selection bias in population-based cancer case-control studies due to incomplete sampling frame coverage.

    Science.gov (United States)

    Walsh, Matthew C; Trentham-Dietz, Amy; Gangnon, Ronald E; Nieto, F Javier; Newcomb, Polly A; Palta, Mari

    2012-06-01

    Increasing numbers of individuals are choosing to opt out of population-based sampling frames due to privacy concerns. This is especially a problem in the selection of controls for case-control studies, as the cases often arise from relatively complete population-based registries, whereas control selection requires a sampling frame. If opt out is also related to risk factors, bias can arise. We linked breast cancer cases who reported having a valid driver's license from the 2004-2008 Wisconsin women's health study (N = 2,988) with a master list of licensed drivers from the Wisconsin Department of Transportation (WDOT). This master list excludes Wisconsin drivers that requested their information not be sold by the state. Multivariate-adjusted selection probability ratios (SPR) were calculated to estimate potential bias when using this driver's license sampling frame to select controls. A total of 962 cases (32%) had opted out of the WDOT sampling frame. Cases age <40 (SPR = 0.90), income either unreported (SPR = 0.89) or greater than $50,000 (SPR = 0.94), lower parity (SPR = 0.96 per one-child decrease), and hormone use (SPR = 0.93) were significantly less likely to be covered by the WDOT sampling frame (α = 0.05 level). Our results indicate the potential for selection bias due to differential opt out between various demographic and behavioral subgroups of controls. As selection bias may differ by exposure and study base, the assessment of potential bias needs to be ongoing. SPRs can be used to predict the direction of bias when cases and controls stem from different sampling frames in population-based case-control studies.

  5. Analysing home-ownership of couples: the effect of selecting couples at the time of the survey.

    Science.gov (United States)

    Mulder, C H

    1996-09-01

    "The analysis of events encountered by couple and family households may suffer from sample selection bias when data are restricted to couples existing at the moment of interview. The paper discusses the effect of sample selection bias on event history analyses of buying a home [in the Netherlands] by comparing analyses performed on a sample of existing couples with analyses of a more complete sample including past as well as current partner relationships. The results show that, although home-buying in relationships that have ended differs clearly from behaviour in existing relationships, sample selection bias is not alarmingly large." (SUMMARY IN FRE) excerpt

  6. Adult health study reference papers. Selection of the sample. Characteristics of the sample

    Energy Technology Data Exchange (ETDEWEB)

    Beebe, G W; Fujisawa, Hideo; Yamasaki, Mitsuru

    1960-12-14

    The characteristics and selection of the clinical sample have been described in some detail to provide information on the comparability of the exposure groups with respect to factors excluded from the matching criteria and to provide basic descriptive information potentially relevant to individual studies that may be done within the framework of the Adult Health Study. The characteristics under review here are age, sex, many different aspects of residence, marital status, occupation and industry, details of location and shielding ATB, acute radiation signs and symptoms, and prior ABCC medical or pathology examinations. 5 references, 57 tables.

  7. A simulative comparison of respondent driven sampling with incentivized snowball sampling--the "strudel effect".

    Science.gov (United States)

    Gyarmathy, V Anna; Johnston, Lisa G; Caplinskiene, Irma; Caplinskas, Saulius; Latkin, Carl A

    2014-02-01

    Respondent driven sampling (RDS) and incentivized snowball sampling (ISS) are two sampling methods that are commonly used to reach people who inject drugs (PWID). We generated a set of simulated RDS samples on an actual sociometric ISS sample of PWID in Vilnius, Lithuania ("original sample") to assess if the simulated RDS estimates were statistically significantly different from the original ISS sample prevalences for HIV (9.8%), Hepatitis A (43.6%), Hepatitis B (Anti-HBc 43.9% and HBsAg 3.4%), Hepatitis C (87.5%), syphilis (6.8%) and Chlamydia (8.8%) infections and for selected behavioral risk characteristics. The original sample consisted of a large component of 249 people (83% of the sample) and 13 smaller components with 1-12 individuals. Generally, as long as all seeds were recruited from the large component of the original sample, the simulation samples simply recreated the large component. There were no significant differences between the large component and the entire original sample for the characteristics of interest. Altogether 99.2% of 360 simulation sample point estimates were within the confidence interval of the original prevalence values for the characteristics of interest. When population characteristics are reflected in large network components that dominate the population, RDS and ISS may produce samples that have statistically non-different prevalence values, even though some isolated network components may be under-sampled and/or statistically significantly different from the main groups. This so-called "strudel effect" is discussed in the paper. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Acceptance sampling using judgmental and randomly selected samples

    Energy Technology Data Exchange (ETDEWEB)

    Sego, Landon H.; Shulman, Stanley A.; Anderson, Kevin K.; Wilson, John E.; Pulsipher, Brent A.; Sieber, W. Karl

    2010-09-01

    We present a Bayesian model for acceptance sampling where the population consists of two groups, each with different levels of risk of containing unacceptable items. Expert opinion, or judgment, may be required to distinguish between the high and low-risk groups. Hence, high-risk items are likely to be identifed (and sampled) using expert judgment, while the remaining low-risk items are sampled randomly. We focus on the situation where all observed samples must be acceptable. Consequently, the objective of the statistical inference is to quantify the probability that a large percentage of the unsampled items in the population are also acceptable. We demonstrate that traditional (frequentist) acceptance sampling and simpler Bayesian formulations of the problem are essentially special cases of the proposed model. We explore the properties of the model in detail, and discuss the conditions necessary to ensure that required samples sizes are non-decreasing function of the population size. The method is applicable to a variety of acceptance sampling problems, and, in particular, to environmental sampling where the objective is to demonstrate the safety of reoccupying a remediated facility that has been contaminated with a lethal agent.

  9. Selective whole genome amplification for resequencing target microbial species from complex natural samples.

    Science.gov (United States)

    Leichty, Aaron R; Brisson, Dustin

    2014-10-01

    Population genomic analyses have demonstrated power to address major questions in evolutionary and molecular microbiology. Collecting populations of genomes is hindered in many microbial species by the absence of a cost effective and practical method to collect ample quantities of sufficiently pure genomic DNA for next-generation sequencing. Here we present a simple method to amplify genomes of a target microbial species present in a complex, natural sample. The selective whole genome amplification (SWGA) technique amplifies target genomes using nucleotide sequence motifs that are common in the target microbe genome, but rare in the background genomes, to prime the highly processive phi29 polymerase. SWGA thus selectively amplifies the target genome from samples in which it originally represented a minor fraction of the total DNA. The post-SWGA samples are enriched in target genomic DNA, which are ideal for population resequencing. We demonstrate the efficacy of SWGA using both laboratory-prepared mixtures of cultured microbes as well as a natural host-microbe association. Targeted amplification of Borrelia burgdorferi mixed with Escherichia coli at genome ratios of 1:2000 resulted in >10(5)-fold amplification of the target genomes with genomic extracts from Wolbachia pipientis-infected Drosophila melanogaster resulted in up to 70% of high-throughput resequencing reads mapping to the W. pipientis genome. By contrast, 2-9% of sequencing reads were derived from W. pipientis without prior amplification. The SWGA technique results in high sequencing coverage at a fraction of the sequencing effort, thus allowing population genomic studies at affordable costs. Copyright © 2014 by the Genetics Society of America.

  10. THE ATACAMA COSMOLOGY TELESCOPE: DYNAMICAL MASSES AND SCALING RELATIONS FOR A SAMPLE OF MASSIVE SUNYAEV-ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTERS {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Sifon, Cristobal; Barrientos, L. Felipe; Gonzalez, Jorge; Infante, Leopoldo; Duenner, Rolando [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Menanteau, Felipe; Hughes, John P.; Baker, Andrew J. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Hasselfield, Matthew [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Marriage, Tobias A.; Crichton, Devin; Gralla, Megan B. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218-2686 (United States); Addison, Graeme E.; Dunkley, Joanna [Sub-department of Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Battaglia, Nick; Bond, J. Richard; Hajian, Amir [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Das, Sudeep [Berkeley Center for Cosmological Physics, LBL and Department of Physics, University of California, Berkeley, CA 94720 (United States); Devlin, Mark J. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Hilton, Matt [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); and others

    2013-07-20

    We present the first dynamical mass estimates and scaling relations for a sample of Sunyaev-Zel'dovich effect (SZE) selected galaxy clusters. The sample consists of 16 massive clusters detected with the Atacama Cosmology Telescope (ACT) over a 455 deg{sup 2} area of the southern sky. Deep multi-object spectroscopic observations were taken to secure intermediate-resolution (R {approx} 700-800) spectra and redshifts for Almost-Equal-To 60 member galaxies on average per cluster. The dynamical masses M{sub 200c} of the clusters have been calculated using simulation-based scaling relations between velocity dispersion and mass. The sample has a median redshift z = 0.50 and a median mass M{sub 200c}{approx_equal}12 Multiplication-Sign 10{sup 14} h{sub 70}{sup -1} M{sub sun} with a lower limit M{sub 200c}{approx_equal}6 Multiplication-Sign 10{sup 14} h{sub 70}{sup -1} M{sub sun}, consistent with the expectations for the ACT southern sky survey. These masses are compared to the ACT SZE properties of the sample, specifically, the match-filtered central SZE amplitude y{sub 0}-tilde, the central Compton parameter y{sub 0}, and the integrated Compton signal Y{sub 200c}, which we use to derive SZE-mass scaling relations. All SZE estimators correlate with dynamical mass with low intrinsic scatter ({approx}< 20%), in agreement with numerical simulations. We explore the effects of various systematic effects on these scaling relations, including the correlation between observables and the influence of dynamically disturbed clusters. Using the three-dimensional information available, we divide the sample into relaxed and disturbed clusters and find that {approx}50% of the clusters are disturbed. There are hints that disturbed systems might bias the scaling relations, but given the current sample sizes, these differences are not significant; further studies including more clusters are required to assess the impact of these clusters on the scaling relations.

  11. Composition of Trace Metals in Dust Samples Collected from Selected High Schools in Pretoria, South Africa

    Directory of Open Access Journals (Sweden)

    J. O. Olowoyo

    2016-01-01

    Full Text Available Potential health risks associated with trace metal pollution have necessitated the importance of monitoring their levels in the environment. The present study investigated the concentrations and compositions of trace metals in dust samples collected from classrooms and playing ground from the selected high schools In Pretoria. Schools were selected from Pretoria based on factors such as proximity to high traffic ways, industrial areas, and residential areas. Thirty-two dust samples were collected from inside and outside the classrooms, where learners often stay during recess period. The dust samples were analysed for trace metal concentrations using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS. The composition of the elements showed that the concentrations of Zn were more than all other elements except from one of the schools. There were significant differences in the concentrations of trace metals from the schools (p<0.05. Regular cleaning, proximity to busy road, and well maintained gardens seem to have positive effects on the concentrations of trace metals recorded from the classrooms dust. The result further revealed a positive correlation for elements such as Pb, Cu, Zn, Mn, and Sb, indicating that the dust might have a common source.

  12. Selection and Mode Effects in Risk Preference Elicitation Experiments

    DEFF Research Database (Denmark)

    von Gaudecker, Hans-Martin; van Soest, Arthur; Wengström, Erik Roland

    2008-01-01

    experiment is drastically below that of the representative sample in the Internet experiment, and average risk aversion is also lower. Considering the student-like subsample of the Internet subjects and comparing a traditional lab design with an Internet-like design in the lab gives two ways to decompose......We combine data from a risk preference elicitation experiment conducted on a representative sample via the Internet with laboratory data on students for the same experiment to investigate effects of implementation mode and of subject pool selection. We find that the frequency of errors in the lab...... shows that these processes are selective in selecting subjects who make fewer errors, but do not lead to biased conclusions on risk preferences. These findings point at the usefulness of the Internet survey as an alternative to a student pool in the laboratory if the ambition is to use the experiments...

  13. Gender Wage Gap : A Semi-Parametric Approach With Sample Selection Correction

    NARCIS (Netherlands)

    Picchio, M.; Mussida, C.

    2010-01-01

    Sizeable gender differences in employment rates are observed in many countries. Sample selection into the workforce might therefore be a relevant issue when estimating gender wage gaps. This paper proposes a new semi-parametric estimator of densities in the presence of covariates which incorporates

  14. 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

  15. Magnetically separable polymer (Mag-MIP) for selective analysis of biotin in food samples.

    Science.gov (United States)

    Uzuriaga-Sánchez, Rosario Josefina; Khan, Sabir; Wong, Ademar; Picasso, Gino; Pividori, Maria Isabel; Sotomayor, Maria Del Pilar Taboada

    2016-01-01

    This work presents an efficient method for the preparation of magnetic nanoparticles modified with molecularly imprinted polymers (Mag-MIP) through core-shell method for the determination of biotin in milk food samples. The functional monomer acrylic acid was selected from molecular modeling, EGDMA was used as cross-linking monomer and AIBN as radical initiator. The Mag-MIP and Mag-NIP were characterized by FTIR, magnetic hysteresis, XRD, SEM and N2-sorption measurements. The capacity of Mag-MIP for biotin adsorption, its kinetics and selectivity were studied in detail. The adsorption data was well described by Freundlich isotherm model with adsorption equilibrium constant (KF) of 1.46 mL g(-1). The selectivity experiments revealed that prepared Mag-MIP had higher selectivity toward biotin compared to other molecules with different chemical structure. The material was successfully applied for the determination of biotin in diverse milk samples using HPLC for quantification of the analyte, obtaining the mean value of 87.4% recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Selection of Sampling Pumps Used for Groundwater Monitoring at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Schalla, Ronald; Webber, William D.; Smith, Ronald M.

    2001-11-05

    The variable frequency drive centrifugal submersible pump, Redi-Flo2a made by Grundfosa, was selected for universal application for Hanford Site groundwater monitoring. Specifications for the selected pump and five other pumps were evaluated against current and future Hanford groundwater monitoring performance requirements, and the Redi-Flo2 was selected as the most versatile and applicable for the range of monitoring conditions. The Redi-Flo2 pump distinguished itself from the other pumps considered because of its wide range in output flow rate and its comparatively moderate maintenance and low capital costs. The Redi-Flo2 pump is able to purge a well at a high flow rate and then supply water for sampling at a low flow rate. Groundwater sampling using a low-volume-purging technique (e.g., low flow, minimal purge, no purge, or micropurgea) is planned in the future, eliminating the need for the pump to supply a high-output flow rate. Under those conditions, the Well Wizard bladder pump, manufactured by QED Environmental Systems, Inc., may be the preferred pump because of the lower capital cost.

  17. Passive sampling of selected endocrine disrupting compounds using polar organic chemical integrative samplers

    International Nuclear Information System (INIS)

    Arditsoglou, Anastasia; Voutsa, Dimitra

    2008-01-01

    Two types of polar organic chemical integrative samplers (pharmaceutical POCIS and pesticide POCIS) were examined for their sampling efficiency of selected endocrine disrupting compounds (EDCs). Laboratory-based calibration of POCISs was conducted by exposing them at high and low concentrations of 14 EDCs (4-alkyl-phenols, their ethoxylate oligomers, bisphenol A, selected estrogens and synthetic steroids) for different time periods. The kinetic studies showed an integrative uptake up to 28 days. The sampling rates for the individual compounds were obtained. The use of POCISs could result in an integrative approach to the quality status of the aquatic systems especially in the case of high variation of water concentrations of EDCs. The sampling efficiency of POCISs under various field conditions was assessed after their deployment in different aquatic environments. - Calibration and field performance of polar organic integrative samplers for monitoring EDCs in aquatic environments

  18. Size selective isocyanate aerosols personal air sampling using porous plastic foams

    International Nuclear Information System (INIS)

    Cong Khanh Huynh; Trinh Vu Duc

    2009-01-01

    As part of a European project (SMT4-CT96-2137), various European institutions specialized in occupational hygiene (BGIA, HSL, IOM, INRS, IST, Ambiente e Lavoro) have established a program of scientific collaboration to develop one or more prototypes of European personal samplers for the collection of simultaneous three dust fractions: inhalable, thoracic and respirable. These samplers based on existing sampling heads (IOM, GSP and cassettes) use Polyurethane Plastic Foam (PUF) according to their porosity to support sampling and separator size of the particles. In this study, the authors present an original application of size selective personal air sampling using chemical impregnated PUF to perform isocyanate aerosols capturing and derivatizing in industrial spray-painting shops.

  19. Vibration and acoustic frequency spectra for industrial process modeling using selective fusion multi-condition samples and multi-source features

    Science.gov (United States)

    Tang, Jian; Qiao, Junfei; Wu, ZhiWei; Chai, Tianyou; Zhang, Jian; Yu, Wen

    2018-01-01

    Frequency spectral data of mechanical vibration and acoustic signals relate to difficult-to-measure production quality and quantity parameters of complex industrial processes. A selective ensemble (SEN) algorithm can be used to build a soft sensor model of these process parameters by fusing valued information selectively from different perspectives. However, a combination of several optimized ensemble sub-models with SEN cannot guarantee the best prediction model. In this study, we use several techniques to construct mechanical vibration and acoustic frequency spectra of a data-driven industrial process parameter model based on selective fusion multi-condition samples and multi-source features. Multi-layer SEN (MLSEN) strategy is used to simulate the domain expert cognitive process. Genetic algorithm and kernel partial least squares are used to construct the inside-layer SEN sub-model based on each mechanical vibration and acoustic frequency spectral feature subset. Branch-and-bound and adaptive weighted fusion algorithms are integrated to select and combine outputs of the inside-layer SEN sub-models. Then, the outside-layer SEN is constructed. Thus, "sub-sampling training examples"-based and "manipulating input features"-based ensemble construction methods are integrated, thereby realizing the selective information fusion process based on multi-condition history samples and multi-source input features. This novel approach is applied to a laboratory-scale ball mill grinding process. A comparison with other methods indicates that the proposed MLSEN approach effectively models mechanical vibration and acoustic signals.

  20. Sample selection based on kernel-subclustering for the signal reconstruction of multifunctional sensors

    International Nuclear Information System (INIS)

    Wang, Xin; Wei, Guo; Sun, Jinwei

    2013-01-01

    The signal reconstruction methods based on inverse modeling for the signal reconstruction of multifunctional sensors have been widely studied in recent years. To improve the accuracy, the reconstruction methods have become more and more complicated because of the increase in the model parameters and sample points. However, there is another factor that affects the reconstruction accuracy, the position of the sample points, which has not been studied. A reasonable selection of the sample points could improve the signal reconstruction quality in at least two ways: improved accuracy with the same number of sample points or the same accuracy obtained with a smaller number of sample points. Both ways are valuable for improving the accuracy and decreasing the workload, especially for large batches of multifunctional sensors. In this paper, we propose a sample selection method based on kernel-subclustering distill groupings of the sample data and produce the representation of the data set for inverse modeling. The method calculates the distance between two data points based on the kernel-induced distance instead of the conventional distance. The kernel function is a generalization of the distance metric by mapping the data that are non-separable in the original space into homogeneous groups in the high-dimensional space. The method obtained the best results compared with the other three methods in the simulation. (paper)

  1. An Improved Nested Sampling Algorithm for Model Selection and Assessment

    Science.gov (United States)

    Zeng, X.; Ye, M.; Wu, J.; WANG, D.

    2017-12-01

    Multimodel strategy is a general approach for treating model structure uncertainty in recent researches. The unknown groundwater system is represented by several plausible conceptual models. Each alternative conceptual model is attached with a weight which represents the possibility of this model. In Bayesian framework, the posterior model weight is computed as the product of model prior weight and marginal likelihood (or termed as model evidence). As a result, estimating marginal likelihoods is crucial for reliable model selection and assessment in multimodel analysis. Nested sampling estimator (NSE) is a new proposed algorithm for marginal likelihood estimation. The implementation of NSE comprises searching the parameters' space from low likelihood area to high likelihood area gradually, and this evolution is finished iteratively via local sampling procedure. Thus, the efficiency of NSE is dominated by the strength of local sampling procedure. Currently, Metropolis-Hasting (M-H) algorithm and its variants are often used for local sampling in NSE. However, M-H is not an efficient sampling algorithm for high-dimensional or complex likelihood function. For improving the performance of NSE, it could be feasible to integrate more efficient and elaborated sampling algorithm - DREAMzs into the local sampling. In addition, in order to overcome the computation burden problem of large quantity of repeating model executions in marginal likelihood estimation, an adaptive sparse grid stochastic collocation method is used to build the surrogates for original groundwater model.

  2. 40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

  3. Varying Coefficient Panel Data Model in the Presence of Endogenous Selectivity and Fixed Effects

    OpenAIRE

    Malikov, Emir; Kumbhakar, Subal C.; Sun, Yiguo

    2013-01-01

    This paper considers a flexible panel data sample selection model in which (i) the outcome equation is permitted to take a semiparametric, varying coefficient form to capture potential parameter heterogeneity in the relationship of interest, (ii) both the outcome and (parametric) selection equations contain unobserved fixed effects and (iii) selection is generalized to a polychotomous case. We propose a two-stage estimator. Given consistent parameter estimates from the selection equation obta...

  4. ACTIVE LEARNING TO OVERCOME SAMPLE SELECTION BIAS: APPLICATION TO PHOTOMETRIC VARIABLE STAR CLASSIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Berian James, J. [Astronomy Department, University of California, Berkeley, CA 94720-7450 (United States); Brink, Henrik [Dark Cosmology Centre, Juliane Maries Vej 30, 2100 Copenhagen O (Denmark); Long, James P.; Rice, John, E-mail: jwrichar@stat.berkeley.edu [Statistics Department, University of California, Berkeley, CA 94720-7450 (United States)

    2012-01-10

    Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL-where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up-is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

  5. ACTIVE LEARNING TO OVERCOME SAMPLE SELECTION BIAS: APPLICATION TO PHOTOMETRIC VARIABLE STAR CLASSIFICATION

    International Nuclear Information System (INIS)

    Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Berian James, J.; Brink, Henrik; Long, James P.; Rice, John

    2012-01-01

    Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL—where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up—is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

  6. Active Learning to Overcome Sample Selection Bias: Application to Photometric Variable Star Classification

    Science.gov (United States)

    Richards, Joseph W.; Starr, Dan L.; Brink, Henrik; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; James, J. Berian; Long, James P.; Rice, John

    2012-01-01

    Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL—where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up—is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

  7. Transfer function design based on user selected samples for intuitive multivariate volume exploration

    KAUST Repository

    Zhou, Liang

    2013-02-01

    Multivariate volumetric datasets are important to both science and medicine. We propose a transfer function (TF) design approach based on user selected samples in the spatial domain to make multivariate volumetric data visualization more accessible for domain users. Specifically, the user starts the visualization by probing features of interest on slices and the data values are instantly queried by user selection. The queried sample values are then used to automatically and robustly generate high dimensional transfer functions (HDTFs) via kernel density estimation (KDE). Alternatively, 2D Gaussian TFs can be automatically generated in the dimensionality reduced space using these samples. With the extracted features rendered in the volume rendering view, the user can further refine these features using segmentation brushes. Interactivity is achieved in our system and different views are tightly linked. Use cases show that our system has been successfully applied for simulation and complicated seismic data sets. © 2013 IEEE.

  8. Transfer function design based on user selected samples for intuitive multivariate volume exploration

    KAUST Repository

    Zhou, Liang; Hansen, Charles

    2013-01-01

    Multivariate volumetric datasets are important to both science and medicine. We propose a transfer function (TF) design approach based on user selected samples in the spatial domain to make multivariate volumetric data visualization more accessible for domain users. Specifically, the user starts the visualization by probing features of interest on slices and the data values are instantly queried by user selection. The queried sample values are then used to automatically and robustly generate high dimensional transfer functions (HDTFs) via kernel density estimation (KDE). Alternatively, 2D Gaussian TFs can be automatically generated in the dimensionality reduced space using these samples. With the extracted features rendered in the volume rendering view, the user can further refine these features using segmentation brushes. Interactivity is achieved in our system and different views are tightly linked. Use cases show that our system has been successfully applied for simulation and complicated seismic data sets. © 2013 IEEE.

  9. Matrix effect study in the determination of linear alkylbenzene sulfonates in sewage sludge samples.

    Science.gov (United States)

    Cantarero, Samuel; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Vílchez, José L; Verge, Coral; De Ferrer, Juan A

    2011-04-01

    We propose a study of the matrix effect in the determination of linear alkylbenzene sulfonates (LAS) in sewage sludge samples. First, a rapid, selective and sensitive method is proposed. The method involves two stages: the extraction of the compound from the samples and analysis by liquid chromatography with fluorescence detection (LC-FLD). Three different techniques of extraction (microwave-assisted extraction, Soxhlet, and ultrasounds) were compared, and microwave-assisted extraction was selected as the best suited for our purpose. Microwave-assisted extraction allows reducing the extraction time (25 min compared with 12 h for conventional Soxhlet extraction) and solvent waste (25 ml of methanol compared with 200 ml for Soxhlet or more than 50 ml for the ultrasonic procedure). Absence of matrix effect was evaluated with two standards (2ØC(8:0) and 2ØC(16:0) ) that are not commercial; therefore, neither of them was detected in sewage sludge samples and they showed similar environmental behavior (adsorption and precipitation) to LAS (C(11:0) -C(13.0) ), which allow us to evaluate the matrix effect. Validation was carried out by a recovery assay, and the method was applied to samples from different sources; therefore, they had different compositions. Copyright © 2011 SETAC.

  10. Selective removal of phosphate for analysis of organic acids in complex samples.

    Science.gov (United States)

    Deshmukh, Sandeep; Frolov, Andrej; Marcillo, Andrea; Birkemeyer, Claudia

    2015-04-03

    Accurate quantitation of compounds in samples of biological origin is often hampered by matrix interferences one of which occurs in GC-MS analysis from the presence of highly abundant phosphate. Consequently, high concentrations of phosphate need to be removed before sample analysis. Within this context, we screened 17 anion exchange solid-phase extraction (SPE) materials for selective phosphate removal using different protocols to meet the challenge of simultaneous recovery of six common organic acids in aqueous samples prior to derivatization for GC-MS analysis. Up to 75% recovery was achieved for the most organic acids, only the low pKa tartaric and citric acids were badly recovered. Compared to the traditional approach of phosphate removal by precipitation, SPE had a broader compatibility with common detection methods and performed more selectively among the organic acids under investigation. Based on the results of this study, it is recommended that phosphate removal strategies during the analysis of biologically relevant small molecular weight organic acids consider the respective pKa of the anticipated analytes and the detection method of choice. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. THE zCOSMOS-SINFONI PROJECT. I. SAMPLE SELECTION AND NATURAL-SEEING OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, C.; Renzini, A. [INAF-OAPD, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Foerster Schreiber, N. M.; Hicks, E. K. S.; Genzel, R.; Tacconi, L.; Davies, R. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Cresci, G. [Osservatorio Astrofisico di Arcetri (OAF), INAF-Firenze, Largo E. Fermi 5, I-50125 Firenze (Italy); Peng, Y.; Lilly, S.; Carollo, M.; Oesch, P. [Institute of Astronomy, Department of Physics, Eidgenossische Technische Hochschule, ETH Zurich CH-8093 (Switzerland); Vergani, D.; Pozzetti, L.; Zamorani, G. [INAF-Bologna, Via Ranzani, I-40127 Bologna (Italy); Daddi, E. [CEA-Saclay, DSM/DAPNIA/Service d' Astrophysique, F-91191 Gif-Sur Yvette Cedex (France); Maraston, C. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, PO1 3HE Portsmouth (United Kingdom); McCracken, H. J. [IAP, 98bis bd Arago, F-75014 Paris (France); Bouche, N. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Shapiro, K. [Aerospace Research Laboratories, Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 (United States); and others

    2011-12-10

    The zCOSMOS-SINFONI project is aimed at studying the physical and kinematical properties of a sample of massive z {approx} 1.4-2.5 star-forming galaxies, through SINFONI near-infrared integral field spectroscopy (IFS), combined with the multiwavelength information from the zCOSMOS (COSMOS) survey. The project is based on one hour of natural-seeing observations per target, and adaptive optics (AO) follow-up for a major part of the sample, which includes 30 galaxies selected from the zCOSMOS/VIMOS spectroscopic survey. This first paper presents the sample selection, and the global physical characterization of the target galaxies from multicolor photometry, i.e., star formation rate (SFR), stellar mass, age, etc. The H{alpha} integrated properties, such as, flux, velocity dispersion, and size, are derived from the natural-seeing observations, while the follow-up AO observations will be presented in the next paper of this series. Our sample appears to be well representative of star-forming galaxies at z {approx} 2, covering a wide range in mass and SFR. The H{alpha} integrated properties of the 25 H{alpha} detected galaxies are similar to those of other IFS samples at the same redshifts. Good agreement is found among the SFRs derived from H{alpha} luminosity and other diagnostic methods, provided the extinction affecting the H{alpha} luminosity is about twice that affecting the continuum. A preliminary kinematic analysis, based on the maximum observed velocity difference across the source and on the integrated velocity dispersion, indicates that the sample splits nearly 50-50 into rotation-dominated and velocity-dispersion-dominated galaxies, in good agreement with previous surveys.

  12. Assessment of selected contaminants in streambed- and suspended-sediment samples collected in Bexar County, Texas, 2007-09

    Science.gov (United States)

    Wilson, Jennifer T.

    2011-01-01

    Elevated concentrations of sediment-associated contaminants are typically associated with urban areas such as San Antonio, Texas, in Bexar County, the seventh most populous city in the United States. This report describes an assessment of selected sediment-associated contaminants in samples collected in Bexar County from sites on the following streams: Medio Creek, Medina River, Elm Creek, Martinez Creek, Chupaderas Creek, Leon Creek, Salado Creek, and San Antonio River. During 2007-09, the U.S. Geological Survey periodically collected surficial streambed-sediment samples during base flow and suspended-sediment (large-volume suspended-sediment) samples from selected streams during stormwater runoff. All sediment samples were analyzed for major and trace elements and for organic compounds including halogenated organic compounds and polycyclic aromatic hydrocarbons (PAHs). Selected contaminants in streambed and suspended sediments in watersheds of the eight major streams in Bexar County were assessed by using a variety of methods—observations of occurrence and distribution, comparison to sediment-quality guidelines and data from previous studies, statistical analyses, and source indicators. Trace elements concentrations were low compared to the consensus-based sediment-quality guidelines threshold effect concentration (TEC) and probable effect concentration (PEC). Trace element concentrations were greater than the TEC in 28 percent of the samples and greater than the PEC in 1.5 percent of the samples. Chromium concentrations exceeded sediment-quality guidelines more frequently than concentrations of any other constituents analyzed in this study (greater than the TEC in 69 percent of samples and greater than the PEC in 8 percent of samples). Mean trace element concentrations generally are lower in Bexar County samples compared to concentrations in samples collected during previous studies in the Austin and Fort Worth, Texas, areas, but considering the relatively

  13. A Bayesian random effects discrete-choice model for resource selection: Population-level selection inference

    Science.gov (United States)

    Thomas, D.L.; Johnson, D.; Griffith, B.

    2006-01-01

    Modeling the probability of use of land units characterized by discrete and continuous measures, we present a Bayesian random-effects model to assess resource selection. This model provides simultaneous estimation of both individual- and population-level selection. Deviance information criterion (DIC), a Bayesian alternative to AIC that is sample-size specific, is used for model selection. Aerial radiolocation data from 76 adult female caribou (Rangifer tarandus) and calf pairs during 1 year on an Arctic coastal plain calving ground were used to illustrate models and assess population-level selection of landscape attributes, as well as individual heterogeneity of selection. Landscape attributes included elevation, NDVI (a measure of forage greenness), and land cover-type classification. Results from the first of a 2-stage model-selection procedure indicated that there is substantial heterogeneity among cow-calf pairs with respect to selection of the landscape attributes. In the second stage, selection of models with heterogeneity included indicated that at the population-level, NDVI and land cover class were significant attributes for selection of different landscapes by pairs on the calving ground. Population-level selection coefficients indicate that the pairs generally select landscapes with higher levels of NDVI, but the relationship is quadratic. The highest rate of selection occurs at values of NDVI less than the maximum observed. Results for land cover-class selections coefficients indicate that wet sedge, moist sedge, herbaceous tussock tundra, and shrub tussock tundra are selected at approximately the same rate, while alpine and sparsely vegetated landscapes are selected at a lower rate. Furthermore, the variability in selection by individual caribou for moist sedge and sparsely vegetated landscapes is large relative to the variability in selection of other land cover types. The example analysis illustrates that, while sometimes computationally intense, a

  14. 40 CFR Appendix A to Subpart G of... - Sampling Plans for Selective Enforcement Auditing of Marine Engines

    Science.gov (United States)

    2010-07-01

    ... Enforcement Auditing of Marine Engines A Appendix A to Subpart G of Part 91 Protection of Environment...-IGNITION ENGINES Selective Enforcement Auditing Regulations Pt. 91, Subpt. G, App. A Appendix A to Subpart G of Part 91—Sampling Plans for Selective Enforcement Auditing of Marine Engines Table 1—Sampling...

  15. Optimizing trial design in pharmacogenetics research: comparing a fixed parallel group, group sequential, and adaptive selection design on sample size requirements.

    Science.gov (United States)

    Boessen, Ruud; van der Baan, Frederieke; Groenwold, Rolf; Egberts, Antoine; Klungel, Olaf; Grobbee, Diederick; Knol, Mirjam; Roes, Kit

    2013-01-01

    Two-stage clinical trial designs may be efficient in pharmacogenetics research when there is some but inconclusive evidence of effect modification by a genomic marker. Two-stage designs allow to stop early for efficacy or futility and can offer the additional opportunity to enrich the study population to a specific patient subgroup after an interim analysis. This study compared sample size requirements for fixed parallel group, group sequential, and adaptive selection designs with equal overall power and control of the family-wise type I error rate. The designs were evaluated across scenarios that defined the effect sizes in the marker positive and marker negative subgroups and the prevalence of marker positive patients in the overall study population. Effect sizes were chosen to reflect realistic planning scenarios, where at least some effect is present in the marker negative subgroup. In addition, scenarios were considered in which the assumed 'true' subgroup effects (i.e., the postulated effects) differed from those hypothesized at the planning stage. As expected, both two-stage designs generally required fewer patients than a fixed parallel group design, and the advantage increased as the difference between subgroups increased. The adaptive selection design added little further reduction in sample size, as compared with the group sequential design, when the postulated effect sizes were equal to those hypothesized at the planning stage. However, when the postulated effects deviated strongly in favor of enrichment, the comparative advantage of the adaptive selection design increased, which precisely reflects the adaptive nature of the design. Copyright © 2013 John Wiley & Sons, Ltd.

  16. 40 CFR Appendix A to Subpart F of... - Sampling Plans for Selective Enforcement Auditing of Nonroad Engines

    Science.gov (United States)

    2010-07-01

    ... Enforcement Auditing of Nonroad Engines A Appendix A to Subpart F of Part 89 Protection of Environment... NONROAD COMPRESSION-IGNITION ENGINES Selective Enforcement Auditing Pt. 89, Subpt. F, App. A Appendix A to Subpart F of Part 89—Sampling Plans for Selective Enforcement Auditing of Nonroad Engines Table 1—Sampling...

  17. Electromembrane extraction as a rapid and selective miniaturized sample preparation technique for biological fluids

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Pedersen-Bjergaard, Stig; Seip, Knut Fredrik

    2015-01-01

    This special report discusses the sample preparation method electromembrane extraction, which was introduced in 2006 as a rapid and selective miniaturized extraction method. The extraction principle is based on isolation of charged analytes extracted from an aqueous sample, across a thin film....... Technical aspects of electromembrane extraction, important extraction parameters as well as a handful of examples of applications from different biological samples and bioanalytical areas are discussed in the paper....

  18. A genetic algorithm-based framework for wavelength selection on sample categorization.

    Science.gov (United States)

    Anzanello, Michel J; Yamashita, Gabrielli; Marcelo, Marcelo; Fogliatto, Flávio S; Ortiz, Rafael S; Mariotti, Kristiane; Ferrão, Marco F

    2017-08-01

    In forensic and pharmaceutical scenarios, the application of chemometrics and optimization techniques has unveiled common and peculiar features of seized medicine and drug samples, helping investigative forces to track illegal operations. This paper proposes a novel framework aimed at identifying relevant subsets of attenuated total reflectance Fourier transform infrared (ATR-FTIR) wavelengths for classifying samples into two classes, for example authentic or forged categories in case of medicines, or salt or base form in cocaine analysis. In the first step of the framework, the ATR-FTIR spectra were partitioned into equidistant intervals and the k-nearest neighbour (KNN) classification technique was applied to each interval to insert samples into proper classes. In the next step, selected intervals were refined through the genetic algorithm (GA) by identifying a limited number of wavelengths from the intervals previously selected aimed at maximizing classification accuracy. When applied to Cialis®, Viagra®, and cocaine ATR-FTIR datasets, the proposed method substantially decreased the number of wavelengths needed to categorize, and increased the classification accuracy. From a practical perspective, the proposed method provides investigative forces with valuable information towards monitoring illegal production of drugs and medicines. In addition, focusing on a reduced subset of wavelengths allows the development of portable devices capable of testing the authenticity of samples during police checking events, avoiding the need for later laboratorial analyses and reducing equipment expenses. Theoretically, the proposed GA-based approach yields more refined solutions than the current methods relying on interval approaches, which tend to insert irrelevant wavelengths in the retained intervals. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Effect of sample stratification on dairy GWAS results

    Directory of Open Access Journals (Sweden)

    Ma Li

    2012-10-01

    Full Text Available Abstract Background Artificial insemination and genetic selection are major factors contributing to population stratification in dairy cattle. In this study, we analyzed the effect of sample stratification and the effect of stratification correction on results of a dairy genome-wide association study (GWAS. Three methods for stratification correction were used: the efficient mixed-model association expedited (EMMAX method accounting for correlation among all individuals, a generalized least squares (GLS method based on half-sib intraclass correlation, and a principal component analysis (PCA approach. Results Historical pedigree data revealed that the 1,654 contemporary cows in the GWAS were all related when traced through approximately 10–15 generations of ancestors. Genome and phenotype stratifications had a striking overlap with the half-sib structure. A large elite half-sib family of cows contributed to the detection of favorable alleles that had low frequencies in the general population and high frequencies in the elite cows and contributed to the detection of X chromosome effects. All three methods for stratification correction reduced the number of significant effects. EMMAX method had the most severe reduction in the number of significant effects, and the PCA method using 20 principal components and GLS had similar significance levels. Removal of the elite cows from the analysis without using stratification correction removed many effects that were also removed by the three methods for stratification correction, indicating that stratification correction could have removed some true effects due to the elite cows. SNP effects with good consensus between different methods and effect size distributions from USDA’s Holstein genomic evaluation included the DGAT1-NIBP region of BTA14 for production traits, a SNP 45kb upstream from PIGY on BTA6 and two SNPs in NIBP on BTA14 for protein percentage. However, most of these consensus effects had

  20. The joint effects of background selection and genetic recombination on local gene genealogies.

    Science.gov (United States)

    Zeng, Kai; Charlesworth, Brian

    2011-09-01

    Background selection, the effects of the continual removal of deleterious mutations by natural selection on variability at linked sites, is potentially a major determinant of DNA sequence variability. However, the joint effects of background selection and genetic recombination on the shape of the neutral gene genealogy have proved hard to study analytically. The only existing formula concerns the mean coalescent time for a pair of alleles, making it difficult to assess the importance of background selection from genome-wide data on sequence polymorphism. Here we develop a structured coalescent model of background selection with recombination and implement it in a computer program that efficiently generates neutral gene genealogies for an arbitrary sample size. We check the validity of the structured coalescent model against forward-in-time simulations and show that it accurately captures the effects of background selection. The model produces more accurate predictions of the mean coalescent time than the existing formula and supports the conclusion that the effect of background selection is greater in the interior of a deleterious region than at its boundaries. The level of linkage disequilibrium between sites is elevated by background selection, to an extent that is well summarized by a change in effective population size. The structured coalescent model is readily extendable to more realistic situations and should prove useful for analyzing genome-wide polymorphism data.

  1. Decomposing the Gender Wage Gap in the Netherlands with Sample Selection Adjustments

    NARCIS (Netherlands)

    Albrecht, James; Vuuren, van Aico; Vroman, Susan

    2004-01-01

    In this paper, we use quantile regression decomposition methods to analyzethe gender gap between men and women who work full time in the Nether-lands. Because the fraction of women working full time in the Netherlands isquite low, sample selection is a serious issue. In addition to shedding light

  2. Statistical sampling plans

    International Nuclear Information System (INIS)

    Jaech, J.L.

    1984-01-01

    In auditing and in inspection, one selects a number of items by some set of procedures and performs measurements which are compared with the operator's values. This session considers the problem of how to select the samples to be measured, and what kinds of measurements to make. In the inspection situation, the ultimate aim is to independently verify the operator's material balance. The effectiveness of the sample plan in achieving this objective is briefly considered. The discussion focuses on the model plant

  3. A redshift survey of IRAS galaxies. I. Sample selection

    International Nuclear Information System (INIS)

    Strauss, M.A.; Davis, M.; Yahil, A.; Huchra, J.P.

    1990-01-01

    A complete all-sky sample of objects, flux-limited at 60 microns, has been extracted from the data base of the IRAS. The sample consists of 5014 objects, of which 2649 are galaxies and 13 are not yet identified. In order to study large-scale structure with this sample, it must be free of systematic biases. Corrections are applied for a major systematic effect in the flux densities listed in the IRAS Point Source Catalog: sources resolved by the IRAS beam have flux densities systematically underestimated. In addition, accurate flux densities are obtained for sources flagged as variable, or of moderate flux quality at 60 microns. The IRAS detectors suffered radiation-induced responsivity enhancement (hysteresis) due to crossings of the satellite scans across the Galactic plane; this effect is measured and is shown to be negligible. 53 refs

  4. Semiparametric efficient and robust estimation of an unknown symmetric population under arbitrary sample selection bias

    KAUST Repository

    Ma, Yanyuan

    2013-09-01

    We propose semiparametric methods to estimate the center and shape of a symmetric population when a representative sample of the population is unavailable due to selection bias. We allow an arbitrary sample selection mechanism determined by the data collection procedure, and we do not impose any parametric form on the population distribution. Under this general framework, we construct a family of consistent estimators of the center that is robust to population model misspecification, and we identify the efficient member that reaches the minimum possible estimation variance. The asymptotic properties and finite sample performance of the estimation and inference procedures are illustrated through theoretical analysis and simulations. A data example is also provided to illustrate the usefulness of the methods in practice. © 2013 American Statistical Association.

  5. Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Curis, Emmanuel [Laboratoire de Biomathematiques, Faculte de Pharmacie, Universite Rene, Descartes (Paris V)-4, Avenue de l' Observatoire, 75006 Paris (France)]. E-mail: emmanuel.curis@univ-paris5.fr; Osan, Janos [KFKI Atomic Energy Research Institute (AEKI)-P.O. Box 49, H-1525 Budapest (Hungary); Falkenberg, Gerald [Hamburger Synchrotronstrahlungslabor (HASYLAB), Deutsches Elektronen-Synchrotron (DESY)-Notkestrasse 85, 22607 Hamburg (Germany); Benazeth, Simone [Laboratoire de Biomathematiques, Faculte de Pharmacie, Universite Rene, Descartes (Paris V)-4, Avenue de l' Observatoire, 75006 Paris (France); Laboratoire d' Utilisation du Rayonnement Electromagnetique (LURE)-Ba-hat timent 209D, Campus d' Orsay, 91406 Orsay (France); Toeroek, Szabina [KFKI Atomic Energy Research Institute (AEKI)-P.O. Box 49, H-1525 Budapest (Hungary)

    2005-07-15

    The article presents an analytical model to simulate experimental imperfections in the realization of an X-ray absorption spectroscopy experiment, performed in transmission or fluorescence mode. Distinction is made between sources of systematic errors on a time-scale basis, to select the more appropriate model for their handling. For short time-scale, statistical models are the most suited. For large time-scale, the model is developed for sample and beam imperfections: mainly sample inhomogeneity, sample self-absorption, beam achromaticity. The ability of this model to reproduce the effects of these imperfections is exemplified, and the model is validated on real samples. Various potential application fields of the model are then presented.

  6. Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

    International Nuclear Information System (INIS)

    Curis, Emmanuel; Osan, Janos; Falkenberg, Gerald; Benazeth, Simone; Toeroek, Szabina

    2005-01-01

    The article presents an analytical model to simulate experimental imperfections in the realization of an X-ray absorption spectroscopy experiment, performed in transmission or fluorescence mode. Distinction is made between sources of systematic errors on a time-scale basis, to select the more appropriate model for their handling. For short time-scale, statistical models are the most suited. For large time-scale, the model is developed for sample and beam imperfections: mainly sample inhomogeneity, sample self-absorption, beam achromaticity. The ability of this model to reproduce the effects of these imperfections is exemplified, and the model is validated on real samples. Various potential application fields of the model are then presented

  7. Soft X-Ray Observations of a Complete Sample of X-Ray--selected BL Lacertae Objects

    Science.gov (United States)

    Perlman, Eric S.; Stocke, John T.; Wang, Q. Daniel; Morris, Simon L.

    1996-01-01

    We present the results of ROSAT PSPC observations of the X-ray selected BL Lacertae objects (XBLs) in the complete Einstein Extended Medium Sensitivity Survey (EM MS) sample. None of the objects is resolved in their respective PSPC images, but all are easily detected. All BL Lac objects in this sample are well-fitted by single power laws. Their X-ray spectra exhibit a variety of spectral slopes, with best-fit energy power-law spectral indices between α = 0.5-2.3. The PSPC spectra of this sample are slightly steeper than those typical of flat ratio-spectrum quasars. Because almost all of the individual PSPC spectral indices are equal to or slightly steeper than the overall optical to X-ray spectral indices for these same objects, we infer that BL Lac soft X-ray continua are dominated by steep-spectrum synchrotron radiation from a broad X-ray jet, rather than flat-spectrum inverse Compton radiation linked to the narrower radio/millimeter jet. The softness of the X-ray spectra of these XBLs revives the possibility proposed by Guilbert, Fabian, & McCray (1983) that BL Lac objects are lineless because the circumnuclear gas cannot be heated sufficiently to permit two stable gas phases, the cooler of which would comprise the broad emission-line clouds. Because unified schemes predict that hard self-Compton radiation is beamed only into a small solid angle in BL Lac objects, the steep-spectrum synchrotron tail controls the temperature of the circumnuclear gas at r ≤ 1018 cm and prevents broad-line cloud formation. We use these new ROSAT data to recalculate the X-ray luminosity function and cosmological evolution of the complete EMSS sample by determining accurate K-corrections for the sample and estimating the effects of variability and the possibility of incompleteness in the sample. Our analysis confirms that XBLs are evolving "negatively," opposite in sense to quasars, with Ve/Va = 0.331±0.060. The statistically significant difference between the values for X

  8. Correlations fo Sc, rare earths and other elements in selected rock samples from Arrua-i

    Energy Technology Data Exchange (ETDEWEB)

    Facetti, J F; Prats, M [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

    1972-01-01

    The Sc and Eu contents in selected rocks samples from the stock of Arrua-i have been determined and correlations established with other elements and with the relative amount of some rare earths. These correlations suggest metasomatic phenomena for the formation of the rock samples.

  9. Correlations fo Sc, rare earths and other elements in selected rock samples from Arrua-i

    International Nuclear Information System (INIS)

    Facetti, J.F.; Prats, M.

    1972-01-01

    The Sc and Eu contents in selected rocks samples from the stock of Arrua-i have been determined and correlations established with other elements and with the relative amount of some rare earths. These correlations suggest metasomatic phenomena for the formation of the rock samples

  10. Non-additive Effects in Genomic Selection

    Directory of Open Access Journals (Sweden)

    Luis Varona

    2018-03-01

    Full Text Available In the last decade, genomic selection has become a standard in the genetic evaluation of livestock populations. However, most procedures for the implementation of genomic selection only consider the additive effects associated with SNP (Single Nucleotide Polymorphism markers used to calculate the prediction of the breeding values of candidates for selection. Nevertheless, the availability of estimates of non-additive effects is of interest because: (i they contribute to an increase in the accuracy of the prediction of breeding values and the genetic response; (ii they allow the definition of mate allocation procedures between candidates for selection; and (iii they can be used to enhance non-additive genetic variation through the definition of appropriate crossbreeding or purebred breeding schemes. This study presents a review of methods for the incorporation of non-additive genetic effects into genomic selection procedures and their potential applications in the prediction of future performance, mate allocation, crossbreeding, and purebred selection. The work concludes with a brief outline of some ideas for future lines of that may help the standard inclusion of non-additive effects in genomic selection.

  11. A Genomic Map of the Effects of Linked Selection in Drosophila.

    Directory of Open Access Journals (Sweden)

    Eyal Elyashiv

    2016-08-01

    Full Text Available Natural selection at one site shapes patterns of genetic variation at linked sites. Quantifying the effects of "linked selection" on levels of genetic diversity is key to making reliable inference about demography, building a null model in scans for targets of adaptation, and learning about the dynamics of natural selection. Here, we introduce the first method that jointly infers parameters of distinct modes of linked selection, notably background selection and selective sweeps, from genome-wide diversity data, functional annotations and genetic maps. The central idea is to calculate the probability that a neutral site is polymorphic given local annotations, substitution patterns, and recombination rates. Information is then combined across sites and samples using composite likelihood in order to estimate genome-wide parameters of distinct modes of selection. In addition to parameter estimation, this approach yields a map of the expected neutral diversity levels along the genome. To illustrate the utility of our approach, we apply it to genome-wide resequencing data from 125 lines in Drosophila melanogaster and reliably predict diversity levels at the 1Mb scale. Our results corroborate estimates of a high fraction of beneficial substitutions in proteins and untranslated regions (UTR. They allow us to distinguish between the contribution of sweeps and other modes of selection around amino acid substitutions and to uncover evidence for pervasive sweeps in untranslated regions (UTRs. Our inference further suggests a substantial effect of other modes of linked selection and of adaptation in particular. More generally, we demonstrate that linked selection has had a larger effect in reducing diversity levels and increasing their variance in D. melanogaster than previously appreciated.

  12. A Genomic Map of the Effects of Linked Selection in Drosophila.

    Science.gov (United States)

    Elyashiv, Eyal; Sattath, Shmuel; Hu, Tina T; Strutsovsky, Alon; McVicker, Graham; Andolfatto, Peter; Coop, Graham; Sella, Guy

    2016-08-01

    Natural selection at one site shapes patterns of genetic variation at linked sites. Quantifying the effects of "linked selection" on levels of genetic diversity is key to making reliable inference about demography, building a null model in scans for targets of adaptation, and learning about the dynamics of natural selection. Here, we introduce the first method that jointly infers parameters of distinct modes of linked selection, notably background selection and selective sweeps, from genome-wide diversity data, functional annotations and genetic maps. The central idea is to calculate the probability that a neutral site is polymorphic given local annotations, substitution patterns, and recombination rates. Information is then combined across sites and samples using composite likelihood in order to estimate genome-wide parameters of distinct modes of selection. In addition to parameter estimation, this approach yields a map of the expected neutral diversity levels along the genome. To illustrate the utility of our approach, we apply it to genome-wide resequencing data from 125 lines in Drosophila melanogaster and reliably predict diversity levels at the 1Mb scale. Our results corroborate estimates of a high fraction of beneficial substitutions in proteins and untranslated regions (UTR). They allow us to distinguish between the contribution of sweeps and other modes of selection around amino acid substitutions and to uncover evidence for pervasive sweeps in untranslated regions (UTRs). Our inference further suggests a substantial effect of other modes of linked selection and of adaptation in particular. More generally, we demonstrate that linked selection has had a larger effect in reducing diversity levels and increasing their variance in D. melanogaster than previously appreciated.

  13. Optimal Selection of the Sampling Interval for Estimation of Modal Parameters by an ARMA- Model

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning

    1993-01-01

    Optimal selection of the sampling interval for estimation of the modal parameters by an ARMA-model for a white noise loaded structure modelled as a single degree of- freedom linear mechanical system is considered. An analytical solution for an optimal uniform sampling interval, which is optimal...

  14. Characterization of selection effects on broiler lines using DNA fingerprinting

    Directory of Open Access Journals (Sweden)

    GS Schmidt

    2003-05-01

    Full Text Available The objective of this study was to evaluate the effect of selection for body weight on the genetic variability and diversity in broiler lines. Two paternal broiler lines (LL and LLc were used. LL line was selected for 12 generations for growth and carcass and reproduction characteristics. The LLc line was established from LL line in 1985 and mated at random. Blood samples from six chickens per line were collected and used for molecular analysis. Also, a DNA pool was made for each line to compare effects between lines. Data were analyzed considering the collected information on the presence or absence of DNA bands. Band sharing scores were calculated using the DICE coefficient. The pattern of the 21 most representative bands was used. DNA fingerprinting (DFP showed 90.48 % of polymorphism bands for both lines. Difference between lines was not due to the presence or absence of bands, but to the frequency of such bands in each genotype. Considering that both lines had the same genetic background, changes on band frequency were probably due to selection. Selection for body weight had an effect on the band frequency as evaluated by DFP, and for this reason this technique could be used as a tool in the selection process. Results also suggest that bands 4, 5 and 19 were linked to body weight traits, and bands 9, 10, 12, 13 and 21 were linked to reproductive traits such as egg production.

  15. Estimating the residential demand function for natural gas in Seoul with correction for sample selection bias

    International Nuclear Information System (INIS)

    Yoo, Seung-Hoon; Lim, Hea-Jin; Kwak, Seung-Jun

    2009-01-01

    Over the last twenty years, the consumption of natural gas in Korea has increased dramatically. This increase has mainly resulted from the rise of consumption in the residential sector. The main objective of the study is to estimate households' demand function for natural gas by applying a sample selection model using data from a survey of households in Seoul. The results show that there exists a selection bias in the sample and that failure to correct for sample selection bias distorts the mean estimate, of the demand for natural gas, downward by 48.1%. In addition, according to the estimation results, the size of the house, the dummy variable for dwelling in an apartment, the dummy variable for having a bed in an inner room, and the household's income all have positive relationships with the demand for natural gas. On the other hand, the size of the family and the price of gas negatively contribute to the demand for natural gas. (author)

  16. Acrylamide exposure among Turkish toddlers from selected cereal-based baby food samples.

    Science.gov (United States)

    Cengiz, Mehmet Fatih; Gündüz, Cennet Pelin Boyacı

    2013-10-01

    In this study, acrylamide exposure from selected cereal-based baby food samples was investigated among toddlers aged 1-3 years in Turkey. The study contained three steps. The first step was collecting food consumption data and toddlers' physical properties, such as gender, age and body weight, using a questionnaire given to parents by a trained interviewer between January and March 2012. The second step was determining the acrylamide levels in food samples that were reported on by the parents in the questionnaire, using a gas chromatography-mass spectrometry (GC-MS) method. The last step was combining the determined acrylamide levels in selected food samples with individual food consumption and body weight data using a deterministic approach to estimate the acrylamide exposure levels. The mean acrylamide levels of baby biscuits, breads, baby bread-rusks, crackers, biscuits, breakfast cereals and powdered cereal-based baby foods were 153, 225, 121, 604, 495, 290 and 36 μg/kg, respectively. The minimum, mean and maximum acrylamide exposures were estimated to be 0.06, 1.43 and 6.41 μg/kg BW per day, respectively. The foods that contributed to acrylamide exposure were aligned from high to low as bread, crackers, biscuits, baby biscuits, powdered cereal-based baby foods, baby bread-rusks and breakfast cereals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Treatment selection in a randomized clinical trial via covariate-specific treatment effect curves.

    Science.gov (United States)

    Ma, Yunbei; Zhou, Xiao-Hua

    2017-02-01

    For time-to-event data in a randomized clinical trial, we proposed two new methods for selecting an optimal treatment for a patient based on the covariate-specific treatment effect curve, which is used to represent the clinical utility of a predictive biomarker. To select an optimal treatment for a patient with a specific biomarker value, we proposed pointwise confidence intervals for each covariate-specific treatment effect curve and the difference between covariate-specific treatment effect curves of two treatments. Furthermore, to select an optimal treatment for a future biomarker-defined subpopulation of patients, we proposed confidence bands for each covariate-specific treatment effect curve and the difference between each pair of covariate-specific treatment effect curve over a fixed interval of biomarker values. We constructed the confidence bands based on a resampling technique. We also conducted simulation studies to evaluate finite-sample properties of the proposed estimation methods. Finally, we illustrated the application of the proposed method in a real-world data set.

  18. Obscured AGN at z similar to 1 from the zCOSMOS-Bright Survey : I. Selection and optical properties of a [Ne v]-selected sample

    NARCIS (Netherlands)

    Mignoli, M.; Vignali, C.; Gilli, R.; Comastri, A.; Zamorani, G.; Bolzonella, M.; Bongiorno, A.; Lamareille, F.; Nair, P.; Pozzetti, L.; Lilly, S. J.; Carollo, C. M.; Contini, T.; Kneib, J. -P.; Le Fevre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Caputi, K.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovac, K.; Le Borgne, J. -F.; Le Brun, V.; Maier, C.; Pello, R.; Peng, Y.; Montero, E. Perez; Presotto, V.; Silverman, J. D.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Bordoloi, R.; Cappi, A.; Cimatti, A.; Koekemoer, A. M.; McCracken, H. J.; Moresco, M.; Welikala, N.

    Aims. The application of multi-wavelength selection techniques is essential for obtaining a complete and unbiased census of active galactic nuclei (AGN). We present here a method for selecting z similar to 1 obscured AGN from optical spectroscopic surveys. Methods. A sample of 94 narrow-line AGN

  19. Estimation of the ancestral effective population sizes of African great apes under different selection regimes.

    Science.gov (United States)

    Schrago, Carlos G

    2014-08-01

    Reliable estimates of ancestral effective population sizes are necessary to unveil the population-level phenomena that shaped the phylogeny and molecular evolution of the African great apes. Although several methods have previously been applied to infer ancestral effective population sizes, an analysis of the influence of the selective regime on the estimates of ancestral demography has not been thoroughly conducted. In this study, three independent data sets under different selective regimes were used were composed to tackle this issue. The results showed that selection had a significant impact on the estimates of ancestral effective population sizes of the African great apes. The inference of the ancestral demography of African great apes was affected by the selection regime. The effects, however, were not homogeneous along the ancestral populations of great apes. The effective population size of the ancestor of humans and chimpanzees was more impacted by the selection regime when compared to the same parameter in the ancestor of humans, chimpanzees and gorillas. Because the selection regime influenced the estimates of ancestral effective population size, it is reasonable to assume that a portion of the discrepancy found in previous studies that inferred the ancestral effective population size may be attributable to the differential action of selection on the genes sampled.

  20. Learning from Past Classification Errors: Exploring Methods for Improving the Performance of a Deep Learning-based Building Extraction Model through Quantitative Analysis of Commission Errors for Optimal Sample Selection

    Science.gov (United States)

    Swan, B.; Laverdiere, M.; Yang, L.

    2017-12-01

    In the past five years, deep Convolutional Neural Networks (CNN) have been increasingly favored for computer vision applications due to their high accuracy and ability to generalize well in very complex problems; however, details of how they function and in turn how they may be optimized are still imperfectly understood. In particular, their complex and highly nonlinear network architecture, including many hidden layers and self-learned parameters, as well as their mathematical implications, presents open questions about how to effectively select training data. Without knowledge of the exact ways the model processes and transforms its inputs, intuition alone may fail as a guide to selecting highly relevant training samples. Working in the context of improving a CNN-based building extraction model used for the LandScan USA gridded population dataset, we have approached this problem by developing a semi-supervised, highly-scalable approach to select training samples from a dataset of identified commission errors. Due to the large scope this project, tens of thousands of potential samples could be derived from identified commission errors. To efficiently trim those samples down to a manageable and effective set for creating additional training sample, we statistically summarized the spectral characteristics of areas with rates of commission errors at the image tile level and grouped these tiles using affinity propagation. Highly representative members of each commission error cluster were then used to select sites for training sample creation. The model will be incrementally re-trained with the new training data to allow for an assessment of how the addition of different types of samples affects the model performance, such as precision and recall rates. By using quantitative analysis and data clustering techniques to select highly relevant training samples, we hope to improve model performance in a manner that is resource efficient, both in terms of training process

  1. Progressive sampling-based Bayesian optimization for efficient and automatic machine learning model selection.

    Science.gov (United States)

    Zeng, Xueqiang; Luo, Gang

    2017-12-01

    Machine learning is broadly used for clinical data analysis. Before training a model, a machine learning algorithm must be selected. Also, the values of one or more model parameters termed hyper-parameters must be set. Selecting algorithms and hyper-parameter values requires advanced machine learning knowledge and many labor-intensive manual iterations. To lower the bar to machine learning, miscellaneous automatic selection methods for algorithms and/or hyper-parameter values have been proposed. Existing automatic selection methods are inefficient on large data sets. This poses a challenge for using machine learning in the clinical big data era. To address the challenge, this paper presents progressive sampling-based Bayesian optimization, an efficient and automatic selection method for both algorithms and hyper-parameter values. We report an implementation of the method. We show that compared to a state of the art automatic selection method, our method can significantly reduce search time, classification error rate, and standard deviation of error rate due to randomization. This is major progress towards enabling fast turnaround in identifying high-quality solutions required by many machine learning-based clinical data analysis tasks.

  2. Determination of Selected Polycyclic Aromatic Compounds in Particulate Matter Samples with Low Mass Loading: An Approach to Test Method Accuracy

    Directory of Open Access Journals (Sweden)

    Susana García-Alonso

    2017-01-01

    Full Text Available A miniaturized analytical procedure to determine selected polycyclic aromatic compounds (PACs in low mass loadings (<10 mg of particulate matter (PM is evaluated. The proposed method is based on a simple sonication/agitation method using small amounts of solvent for extraction. The use of a reduced sample size of particulate matter is often limiting for allowing the quantification of analytes. This also leads to the need for changing analytical procedures and evaluating its performance. The trueness and precision of the proposed method were tested using ambient air samples. Analytical results from the proposed method were compared with those of pressurized liquid and microwave extractions. Selected PACs (polycyclic aromatic hydrocarbons (PAHs and nitro polycyclic aromatic hydrocarbons (NPAHs were determined by liquid chromatography with fluorescence detection (HPLC/FD. Taking results from pressurized liquid extractions as reference values, recovery rates of sonication/agitation method were over 80% for the most abundant PAHs. Recovery rates of selected NPAHs were lower. Enhanced rates were obtained when methanol was used as a modifier. Intermediate precision was estimated by data comparison from two mathematical approaches: normalized difference data and pooled relative deviations. Intermediate precision was in the range of 10–20%. The effectiveness of the proposed method was evaluated in PM aerosol samples collected with very low mass loadings (<0.2 mg during characterization studies from turbofan engine exhausts.

  3. Development of ion imprinted polymers for the selective extraction of lanthanides from environmental samples

    International Nuclear Information System (INIS)

    Moussa, Manel

    2016-01-01

    The analysis of the lanthanide ions present at trace level in complex environmental matrices requires often a purification and preconcentration step. The solid phase extraction (SPE) is the most used sample preparation technique. To improve the selectivity of this step, Ion Imprinted Polymers (IIPs) can be used as SPE solid supports. The aim of this work was the development of IIPs for the selective extraction of lanthanide ions from environmental samples. In a first part, IIPs were prepared according to the trapping approach using 5,7-dichloroquinoline-8-ol as non-vinylated ligand. For the first time, the loss of the trapped ligand during template ion removal and sedimentation steps was demonstrated by HPLC-UV. Moreover, this loss was not repeatable, which led to a lack of repeatability of the SPE profiles. It was then demonstrated that the trapping approach is not appropriate for the IIPs synthesis. In a second part, IIPs were synthesized by chemical immobilization of methacrylic acid as vinylated monomer. The repeatability of the synthesis and the SPE protocol were confirmed. A good selectivity of the IIPs for all the lanthanide ions was obtained. IIPs were successfully used to selectively extract lanthanide ions from tap and river water. Finally, IIPs were synthesized by chemical immobilization of methacrylic acid and 4-vinylpyridine as functional monomers and either a light (Nd 3+ ) or a heavy (Er 3+ ) lanthanide ion as template. Both kinds of IIPs led to a similar selectivity for all lanthanide ions. Nevertheless, this selectivity can be modified by changing the nature and the pH of the washing solution used in the SPE protocol. (author)

  4. The diagnostic value of CT scan and selective venous sampling in Cushing's syndrome

    International Nuclear Information System (INIS)

    Negoro, Makoto; Kuwayama, Akio; Yamamoto, Naoto; Nakane, Toshichi; Yokoe, Toshio; Kageyama, Naoki; Ichihara, Kaoru; Ishiguchi, Tsuneo; Sakuma, Sadayuki

    1986-01-01

    We studied 24 patients with Cushing's syndrome in order to find the best way to confirm the pituitary adenoma preoperatively. At first, the sellar content was studied by means of a high-resolution CT scan in each patient. Second, by selective catheterization in the bilateral internal jugular vein and the inferior petrosal sinus, venous samples (c) were obtained for ACTH assay. Simultaneously, peripheral blood sampling (P) was made at the anterior cubital vein for the same purpose, and the C/P ratio was carefully calculated in each patient. If the C/P ratio exceeded 2, it was highly suggestive of the presence of pituitary adenoma. Even by an advanced high-resolution CT scan with a thickness of 2 mm, pituitary adenomas were detected in only 32 % of the patients studied. The result of image diagnosis in Cushing disease was discouraging. As for the chemical diagnosis, the results were as follows. At the early stage of this study, the catheterization was terminated in the jugular veins of nine patients. Among these, in five patients the presence of pituitary adenoma was predicted correctly in the preoperative stage. Later, by means of inferior petrosal sinus samplings, pituitary microadenomas were detected in ten patients among the twelve. Selective venous sampling for ACTH in the inferior petrosal sinus or jugular vein proved to be useful for the differential diagnosis of Cushing's syndrome when other diagnostic measures such as CT scan were inconclusive. (author)

  5. Selecting Sample Preparation Workflows for Mass Spectrometry-Based Proteomic and Phosphoproteomic Analysis of Patient Samples with Acute Myeloid Leukemia.

    Science.gov (United States)

    Hernandez-Valladares, Maria; Aasebø, Elise; Selheim, Frode; Berven, Frode S; Bruserud, Øystein

    2016-08-22

    Global mass spectrometry (MS)-based proteomic and phosphoproteomic studies of acute myeloid leukemia (AML) biomarkers represent a powerful strategy to identify and confirm proteins and their phosphorylated modifications that could be applied in diagnosis and prognosis, as a support for individual treatment regimens and selection of patients for bone marrow transplant. MS-based studies require optimal and reproducible workflows that allow a satisfactory coverage of the proteome and its modifications. Preparation of samples for global MS analysis is a crucial step and it usually requires method testing, tuning and optimization. Different proteomic workflows that have been used to prepare AML patient samples for global MS analysis usually include a standard protein in-solution digestion procedure with a urea-based lysis buffer. The enrichment of phosphopeptides from AML patient samples has previously been carried out either with immobilized metal affinity chromatography (IMAC) or metal oxide affinity chromatography (MOAC). We have recently tested several methods of sample preparation for MS analysis of the AML proteome and phosphoproteome and introduced filter-aided sample preparation (FASP) as a superior methodology for the sensitive and reproducible generation of peptides from patient samples. FASP-prepared peptides can be further fractionated or IMAC-enriched for proteome or phosphoproteome analyses. Herein, we will review both in-solution and FASP-based sample preparation workflows and encourage the use of the latter for the highest protein and phosphorylation coverage and reproducibility.

  6. Molecularly imprinted membrane extraction combined with high-performance liquid chromatography for selective analysis of cloxacillin from shrimp samples.

    Science.gov (United States)

    Du, Wei; Sun, Min; Guo, Pengqi; Chang, Chun; Fu, Qiang

    2018-09-01

    Nowadays, the abuse of antibiotics in aquaculture has generated considerable problems for food safety. Therefore, it is imperative to develop a simple and selective method for monitoring illegal use of antibiotics in aquatic products. In this study, a method combined molecularly imprinted membranes (MIMs) extraction and liquid chromatography was developed for the selective analysis of cloxacillin from shrimp samples. The MIMs was synthesized by UV photopolymerization, and characterized by scanning electron microscope, Fourier transform infrared spectra, thermo-gravimetric analysis and swelling test. The results showed that the MIMs exhibited excellent permselectivity, high adsorption capacity and fast adsorption rate for cloxacillin. Finally, the method was utilized to determine cloxacillin from shrimp samples, with good accuracies and acceptable relative standard deviation values for precision. The proposed method was a promising alternative for selective analysis of cloxacillin in shrimp samples, due to the easy-operation and excellent selectivity. Copyright © 2018. Published by Elsevier Ltd.

  7. STAR FORMATION LAWS: THE EFFECTS OF GAS CLOUD SAMPLING

    International Nuclear Information System (INIS)

    Calzetti, D.; Liu, G.; Koda, J.

    2012-01-01

    Recent observational results indicate that the functional shape of the spatially resolved star formation-molecular gas density relation depends on the spatial scale considered. These results may indicate a fundamental role of sampling effects on scales that are typically only a few times larger than those of the largest molecular clouds. To investigate the impact of this effect, we construct simple models for the distribution of molecular clouds in a typical star-forming spiral galaxy and, assuming a power-law relation between star formation rate (SFR) and cloud mass, explore a range of input parameters. We confirm that the slope and the scatter of the simulated SFR-molecular gas surface density relation depend on the size of the sub-galactic region considered, due to stochastic sampling of the molecular cloud mass function, and the effect is larger for steeper relations between SFR and molecular gas. There is a general trend for all slope values to tend to ∼unity for region sizes larger than 1-2 kpc, irrespective of the input SFR-cloud relation. The region size of 1-2 kpc corresponds to the area where the cloud mass function becomes fully sampled. We quantify the effects of selection biases in data tracing the SFR, either as thresholds (i.e., clouds smaller than a given mass value do not form stars) or as backgrounds (e.g., diffuse emission unrelated to current star formation is counted toward the SFR). Apparently discordant observational results are brought into agreement via this simple model, and the comparison of our simulations with data for a few galaxies supports a steep (>1) power-law index between SFR and molecular gas.

  8. Re-Emergence of Under-Selected Stimuli, after the Extinction of Over-Selected Stimuli in an Automated Match to Samples Procedure

    Science.gov (United States)

    Broomfield, Laura; McHugh, Louise; Reed, Phil

    2008-01-01

    Stimulus over-selectivity occurs when one of potentially many aspects of the environment comes to control behaviour. In two experiments, adults with no developmental disabilities, were trained and tested in an automated match to samples (MTS) paradigm. In Experiment 1, participants completed two conditions, in one of which the over-selected…

  9. The AlSi10Mg samples produced by selective laser melting: single track, densification, microstructure and mechanical behavior

    International Nuclear Information System (INIS)

    Wei, Pei; Wei, Zhengying; Chen, Zhen; Du, Jun; He, Yuyang; Li, Junfeng; Zhou, Yatong

    2017-01-01

    Highlights: • The thermal behavior of AlSi10Mg molten pool was analyzed. • The SLM-processed sample with a relatively low surface roughness was obtained. • Effects of parameters on surface topography of scan track were investigated. • Effects of parameters on microstructure of parts were investigated. • Optimum processing parameters for AlSi10Mg SLM was obtained. - Abstract: This densification behavior and attendant microstructural characteristics of the selective laser melting (SLM) processed AlSi10Mg alloy affected by the processing parameters were systematically investigated. The samples with a single track were produced by SLM to study the influences of laser power and scanning speed on the surface morphologies of scan tracks. Additionally, the bulk samples were produced to investigate the influence of the laser power, scanning speed, and hatch spacing on the densification level and the resultant microstructure. The experimental results showed that the level of porosity of the SLM-processed samples was significantly governed by energy density of laser beam and the hatch spacing. The tensile properties of SLM-processed samples and the attendant fracture surface can be enhanced by decreasing the level of porosity. The microstructure of SLM-processed samples consists of supersaturated Al-rich cellular structure along with eutectic Al/Si situated at the cellular boundaries. The Si content in the cellular boundaries increases with increasing the laser power and decreasing the scanning speed. The hardness of SLM-processed samples was significantly improved by this fine microstructure compared with the cast samples. Moreover, the hardness of SLM-processed samples at overlaps was lower than the hardness observed at track cores.

  10. The AlSi10Mg samples produced by selective laser melting: single track, densification, microstructure and mechanical behavior

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Pei; Wei, Zhengying, E-mail: zywei@mail.xjtu.edu.cn; Chen, Zhen; Du, Jun; He, Yuyang; Li, Junfeng; Zhou, Yatong

    2017-06-30

    Highlights: • The thermal behavior of AlSi10Mg molten pool was analyzed. • The SLM-processed sample with a relatively low surface roughness was obtained. • Effects of parameters on surface topography of scan track were investigated. • Effects of parameters on microstructure of parts were investigated. • Optimum processing parameters for AlSi10Mg SLM was obtained. - Abstract: This densification behavior and attendant microstructural characteristics of the selective laser melting (SLM) processed AlSi10Mg alloy affected by the processing parameters were systematically investigated. The samples with a single track were produced by SLM to study the influences of laser power and scanning speed on the surface morphologies of scan tracks. Additionally, the bulk samples were produced to investigate the influence of the laser power, scanning speed, and hatch spacing on the densification level and the resultant microstructure. The experimental results showed that the level of porosity of the SLM-processed samples was significantly governed by energy density of laser beam and the hatch spacing. The tensile properties of SLM-processed samples and the attendant fracture surface can be enhanced by decreasing the level of porosity. The microstructure of SLM-processed samples consists of supersaturated Al-rich cellular structure along with eutectic Al/Si situated at the cellular boundaries. The Si content in the cellular boundaries increases with increasing the laser power and decreasing the scanning speed. The hardness of SLM-processed samples was significantly improved by this fine microstructure compared with the cast samples. Moreover, the hardness of SLM-processed samples at overlaps was lower than the hardness observed at track cores.

  11. Effects of fading and spatial correlation on node selection for estimation in Wireless Sensor Networks

    KAUST Repository

    Al-Murad, Tamim M.

    2010-06-01

    In densely deployed sensor networks, correlation among measurements may be high. Spatial sampling through node selection is usually used to minimize this correlation and to save energy consumption. However because of the fading nature of the wireless channels, extra care should be taken when performing this sampling. In this paper, we develop expressions for the distortion which include the channel effects. The asymptotic behavior of the distortion as the number of sensors or total transmit power increase without bound is also investigated. Further, based on the channel and position information we propose and test several node selection schemes.

  12. Antibiotic content of selective culture media for isolation of Capnocytophaga species from oral polymicrobial samples.

    Science.gov (United States)

    Ehrmann, E; Jolivet-Gougeon, A; Bonnaure-Mallet, M; Fosse, T

    2013-10-01

    In oral microbiome, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of fastidious Capnocytophaga species. The performances of six culture media (blood agar, chocolate blood agar, VCAT medium, CAPE medium, bacitracin chocolate blood agar and VK medium) were compared with literature data concerning five other media (FAA, LB, TSBV, CapR and TBBP media). To understand variable growth on selective media, the MICs of each antimicrobial agent contained in this different media (colistin, kanamycin, trimethoprim, trimethoprim-sulfamethoxazole, vancomycin, aztreonam and bacitracin) were determined for all Capnocytophaga species. Overall, VCAT medium (Columbia, 10% cooked horse blood, polyvitaminic supplement, 3·75 mg l(-1) of colistin, 1·5 mg l(-1) of trimethoprim, 1 mg l(-1) of vancomycin and 0·5 mg l(-1) of amphotericin B, Oxoid, France) was the more efficient selective medium, with regard to the detection of Capnocytophaga species from oral samples (P culture, a simple blood agar allowed the growth of all Capnocytophaga species. Nonetheless, in oral samples, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of Capnocytophaga species. The demonstrated superiority of VCAT medium made its use essential for the optimal detection of this bacterial genus. This work showed that extreme caution should be exercised when reporting the isolation of Capnocytophaga species from oral polymicrobial samples, because the culture medium is a determining factor. © 2013 The Society for Applied Microbiology.

  13. Selecting Sample Preparation Workflows for Mass Spectrometry-Based Proteomic and Phosphoproteomic Analysis of Patient Samples with Acute Myeloid Leukemia

    Directory of Open Access Journals (Sweden)

    Maria Hernandez-Valladares

    2016-08-01

    Full Text Available Global mass spectrometry (MS-based proteomic and phosphoproteomic studies of acute myeloid leukemia (AML biomarkers represent a powerful strategy to identify and confirm proteins and their phosphorylated modifications that could be applied in diagnosis and prognosis, as a support for individual treatment regimens and selection of patients for bone marrow transplant. MS-based studies require optimal and reproducible workflows that allow a satisfactory coverage of the proteome and its modifications. Preparation of samples for global MS analysis is a crucial step and it usually requires method testing, tuning and optimization. Different proteomic workflows that have been used to prepare AML patient samples for global MS analysis usually include a standard protein in-solution digestion procedure with a urea-based lysis buffer. The enrichment of phosphopeptides from AML patient samples has previously been carried out either with immobilized metal affinity chromatography (IMAC or metal oxide affinity chromatography (MOAC. We have recently tested several methods of sample preparation for MS analysis of the AML proteome and phosphoproteome and introduced filter-aided sample preparation (FASP as a superior methodology for the sensitive and reproducible generation of peptides from patient samples. FASP-prepared peptides can be further fractionated or IMAC-enriched for proteome or phosphoproteome analyses. Herein, we will review both in-solution and FASP-based sample preparation workflows and encourage the use of the latter for the highest protein and phosphorylation coverage and reproducibility.

  14. Selective extraction of dimethoate from cucumber samples by use of molecularly imprinted microspheres

    Directory of Open Access Journals (Sweden)

    Jiao-Jiao Du

    2015-06-01

    Full Text Available Molecularly imprinted polymers for dimethoate recognition were synthesized by the precipitation polymerization technique using methyl methacrylate (MMA as the functional monomer and ethylene glycol dimethacrylate (EGDMA as the cross-linker. The morphology, adsorption and recognition properties were investigated by scanning electron microscopy (SEM, static adsorption test, and competitive adsorption test. To obtain the best selectivity and binding performance, the synthesis and adsorption conditions of MIPs were optimized through single factor experiments. Under the optimized conditions, the resultant polymers exhibited uniform size, satisfactory binding capacity and significant selectivity. Furthermore, the imprinted polymers were successfully applied as a specific solid-phase extractants combined with high performance liquid chromatography (HPLC for determination of dimethoate residues in the cucumber samples. The average recoveries of three spiked samples ranged from 78.5% to 87.9% with the relative standard deviations (RSDs less than 4.4% and the limit of detection (LOD obtained for dimethoate as low as 2.3 μg/mL. Keywords: Molecularly imprinted polymer, Precipitation polymerization, Dimethoate, Cucumber, HPLC

  15. X-Ray Temperatures, Luminosities, and Masses from XMM-Newton Follow-up of the First Shear-selected Galaxy Cluster Sample

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Amruta J.; Hughes, John P. [Department of Physics and Astronomy, Rutgers the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Wittman, David, E-mail: amrejd@physics.rutgers.edu, E-mail: jph@physics.rutgers.edu, E-mail: dwittman@physics.ucdavis.edu [Department of Physics, University of California, Davis, One Shields Avenue, Davis, CA 95616 (United States)

    2017-04-20

    We continue the study of the first sample of shear-selected clusters from the initial 8.6 square degrees of the Deep Lens Survey (DLS); a sample with well-defined selection criteria corresponding to the highest ranked shear peaks in the survey area. We aim to characterize the weak lensing selection by examining the sample’s X-ray properties. There are multiple X-ray clusters associated with nearly all the shear peaks: 14 X-ray clusters corresponding to seven DLS shear peaks. An additional three X-ray clusters cannot be definitively associated with shear peaks, mainly due to large positional offsets between the X-ray centroid and the shear peak. Here we report on the XMM-Newton properties of the 17 X-ray clusters. The X-ray clusters display a wide range of luminosities and temperatures; the L {sub X} − T {sub X} relation we determine for the shear-associated X-ray clusters is consistent with X-ray cluster samples selected without regard to dynamical state, while it is inconsistent with self-similarity. For a subset of the sample, we measure X-ray masses using temperature as a proxy, and compare to weak lensing masses determined by the DLS team. The resulting mass comparison is consistent with equality. The X-ray and weak lensing masses show considerable intrinsic scatter (∼48%), which is consistent with X-ray selected samples when their X-ray and weak lensing masses are independently determined.

  16. Phytochemical analysis and biological evaluation of selected African propolis samples from Cameroon and Congo

    NARCIS (Netherlands)

    Papachroni, D.; Graikou, K.; Kosalec, I.; Damianakos, H.; Ingram, V.J.; Chinou, I.

    2015-01-01

    The objective of this study was the chemical analysis of four selected samples of African propolis (Congo and Cameroon) and their biological evaluation. Twenty-one secondary metabolites belonging to four different chemical groups were isolated from the 70% ethanolic extracts of propolis and their

  17. Climate Change and Agricultural Productivity in Sub-Saharan Africa: A Spatial Sample Selection Model

    NARCIS (Netherlands)

    Ward, P.S.; Florax, R.J.G.M.; Flores-Lagunes, A.

    2014-01-01

    Using spatially explicit data, we estimate a cereal yield response function using a recently developed estimator for spatial error models when endogenous sample selection is of concern. Our results suggest that yields across Sub-Saharan Africa will decline with projected climatic changes, and that

  18. Nanostructured conducting molecularly imprinted polymer for selective extraction of salicylate from urine and serum samples by electrochemically controlled solid-phase micro-extraction

    Energy Technology Data Exchange (ETDEWEB)

    Ameli, Akram [Department of Chemistry, Faculty of Science, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Alizadeh, Naader, E-mail: alizaden@modares.ac.ir [Department of Chemistry, Faculty of Science, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer Overoxidized polypyrrole templated with salicylate has been utilized as conducting molecular imprinted polymer for EC-SPME. Black-Right-Pointing-Pointer This first study reported on conducting molecular imprinted polymer was used to EC-SPME of salicylate. Black-Right-Pointing-Pointer Proposed method, is particularly effective in sample clean-up and selective monitoring of salicylate in physiological samples. - Abstract: Overoxidized polypyrrole (OPPy) films templated with salicylate (SA) have been utilized as conducting molecular imprinted polymers (CMIPs) for potential-induced selective solid-phase micro-extraction processes. Various important fabrication factors for controlling the performance of the OPPy films have been investigated using fluorescence spectrometry. Several key parameters such as applied potential for uptake, release, pH of uptake and release solution were varied to achieve the optimum micro-extraction procedure. The film template with SA exhibited excellent selectivity over some interference. The calibration graphs were linear in the ranges of 5 Multiplication-Sign 10{sup -8} to 5 Multiplication-Sign 10{sup -4} and 1.2 Multiplication-Sign 10{sup -6} to 5 Multiplication-Sign 10{sup -4} mol mL{sup -1} and the detection limit was 4 Multiplication-Sign 10{sup -8} mol L{sup -1}. The OPPy film as the solid-phase micro-extraction absorbent has been applied for the selective clean-up and quantification of trace amounts of SA from physiological samples. The results of scanning electron microscopy (SEM) have confirmed the nano-structure morphologies of the films.

  19. Nanostructured conducting molecularly imprinted polymer for selective extraction of salicylate from urine and serum samples by electrochemically controlled solid-phase micro-extraction

    International Nuclear Information System (INIS)

    Ameli, Akram; Alizadeh, Naader

    2011-01-01

    Highlights: ► Overoxidized polypyrrole templated with salicylate has been utilized as conducting molecular imprinted polymer for EC-SPME. ► This first study reported on conducting molecular imprinted polymer was used to EC-SPME of salicylate. ► Proposed method, is particularly effective in sample clean-up and selective monitoring of salicylate in physiological samples. - Abstract: Overoxidized polypyrrole (OPPy) films templated with salicylate (SA) have been utilized as conducting molecular imprinted polymers (CMIPs) for potential-induced selective solid-phase micro-extraction processes. Various important fabrication factors for controlling the performance of the OPPy films have been investigated using fluorescence spectrometry. Several key parameters such as applied potential for uptake, release, pH of uptake and release solution were varied to achieve the optimum micro-extraction procedure. The film template with SA exhibited excellent selectivity over some interference. The calibration graphs were linear in the ranges of 5 × 10 −8 to 5 × 10 −4 and 1.2 × 10 −6 to 5 × 10 −4 mol mL −1 and the detection limit was 4 × 10 −8 mol L −1 . The OPPy film as the solid-phase micro-extraction absorbent has been applied for the selective clean-up and quantification of trace amounts of SA from physiological samples. The results of scanning electron microscopy (SEM) have confirmed the nano-structure morphologies of the films.

  20. A novel method of selective removal of human DNA improves PCR sensitivity for detection of Salmonella Typhi in blood samples.

    Science.gov (United States)

    Zhou, Liqing; Pollard, Andrew J

    2012-07-27

    Enteric fever is a major public health problem, causing an estimated 21million new cases and 216,000 or more deaths every year. Current diagnosis of the disease is inadequate. Blood culture only identifies 45 to 70% of the cases and is time-consuming. Serological tests have very low sensitivity and specificity. Clinical samples obtained for diagnosis of enteric fever in the field generally have blood, so that even PCR-based methods, widely used for detection of other infectious diseases, are not a straightforward option in typhoid diagnosis. We developed a novel method to enrich target bacterial DNA by selective removal of human DNA from blood samples, enhancing the sensitivity of PCR tests. This method offers the possibility of improving PCR assays directly using clinical specimens for diagnosis of this globally important infectious disease. Blood samples were mixed with ox bile for selective lysis of human blood cells and the released human DNA was then digested with addition of bile resistant micrococcal nuclease. The intact Salmonella Typhi bacteria were collected from the specimen by centrifugation and the DNA extracted with QIAamp DNA mini kit. The presence of Salmonella Typhi bacteria in blood samples was detected by PCR with the fliC-d gene of Salmonella Typhi as the target. Micrococcal nuclease retained activity against human blood DNA in the presence of up to 9% ox bile. Background human DNA was dramatically removed from blood samples through the use of ox bile lysis and micrococcal nuclease for removal of mammalian DNA. Consequently target Salmonella Typhi DNA was enriched in DNA preparations and the PCR sensitivity for detection of Salmonella Typhi in spiked blood samples was enhanced by 1,000 fold. Use of a combination of selective ox-bile blood cell lysis and removal of human DNA with micrococcal nuclease significantly improves PCR sensitivity and offers a better option for improved typhoid PCR assays directly using clinical specimens in diagnosis of

  1. Effect of colloid (Androcoll-Bear, Percoll, and PureSperm) selection on the freezability of brown bear (Ursus arctos) sperm.

    Science.gov (United States)

    Álvarez-Rodríguez, M; Álvarez, M; Anel-López, L; López-Urueña, E; Manrique, P; Borragán, S; Morrell, J M; de Paz, P; Anel, L

    2016-04-01

    The development of a species-specific conservation protocol that involves artificial insemination with frozen semen needs to validate an effective methodology for freezing semen. Colloid centrifugation has been suggested and widely applied as an effective tool for selecting animal spermatozoa for artificial breeding. The objective of the present study was to compare different methods of centrifugation, single layer using Androcoll-Bear and Percoll and double layer using PureSperm 100 (in two different discontinuous gradients 40%-80% and 45%-90%), for the selection of fresh brown bear sperm samples. In the before freezing group, all selected samples showed a higher progressive motility and viability (except Percoll for motility 43.0 ± 5.3 [P Bear in number of damaged acrosomes, different relative to the control (control, 5.3 ± 0.6; PureSperm 80, 2.0 ± 0.3; Androcoll, 2.1 ± 0.9 [P Bear constitutes a useful tool for handling of brown bear ejaculates owing to its simple handling and procedure with a reliable sperm selection and freezability. This colloid yielded an improvement in several sperm parameters in brown bear frozen-thawed semen; the selected spermatozoa of fresh samples with this colloid showed a better resistance to freezing compared with the control sample not only for motility but also for viability. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Choosing a suitable sample size in descriptive sampling

    International Nuclear Information System (INIS)

    Lee, Yong Kyun; Choi, Dong Hoon; Cha, Kyung Joon

    2010-01-01

    Descriptive sampling (DS) is an alternative to crude Monte Carlo sampling (CMCS) in finding solutions to structural reliability problems. It is known to be an effective sampling method in approximating the distribution of a random variable because it uses the deterministic selection of sample values and their random permutation,. However, because this method is difficult to apply to complex simulations, the sample size is occasionally determined without thorough consideration. Input sample variability may cause the sample size to change between runs, leading to poor simulation results. This paper proposes a numerical method for choosing a suitable sample size for use in DS. Using this method, one can estimate a more accurate probability of failure in a reliability problem while running a minimal number of simulations. The method is then applied to several examples and compared with CMCS and conventional DS to validate its usefulness and efficiency

  3. Are quantitative trait-dependent sampling designs cost-effective for analysis of rare and common variants?

    Science.gov (United States)

    Yilmaz, Yildiz E; Bull, Shelley B

    2011-11-29

    Use of trait-dependent sampling designs in whole-genome association studies of sequence data can reduce total sequencing costs with modest losses of statistical efficiency. In a quantitative trait (QT) analysis of data from the Genetic Analysis Workshop 17 mini-exome for unrelated individuals in the Asian subpopulation, we investigate alternative designs that sequence only 50% of the entire cohort. In addition to a simple random sampling design, we consider extreme-phenotype designs that are of increasing interest in genetic association analysis of QTs, especially in studies concerned with the detection of rare genetic variants. We also evaluate a novel sampling design in which all individuals have a nonzero probability of being selected into the sample but in which individuals with extreme phenotypes have a proportionately larger probability. We take differential sampling of individuals with informative trait values into account by inverse probability weighting using standard survey methods which thus generalizes to the source population. In replicate 1 data, we applied the designs in association analysis of Q1 with both rare and common variants in the FLT1 gene, based on knowledge of the generating model. Using all 200 replicate data sets, we similarly analyzed Q1 and Q4 (which is known to be free of association with FLT1) to evaluate relative efficiency, type I error, and power. Simulation study results suggest that the QT-dependent selection designs generally yield greater than 50% relative efficiency compared to using the entire cohort, implying cost-effectiveness of 50% sample selection and worthwhile reduction of sequencing costs.

  4. Sample selection via angular distance in the space of the arguments of an artificial neural network

    Science.gov (United States)

    Fernández Jaramillo, J. M.; Mayerle, R.

    2018-05-01

    In the construction of an artificial neural network (ANN) a proper data splitting of the available samples plays a major role in the training process. This selection of subsets for training, testing and validation affects the generalization ability of the neural network. Also the number of samples has an impact in the time required for the design of the ANN and the training. This paper introduces an efficient and simple method for reducing the set of samples used for training a neural network. The method reduces the required time to calculate the network coefficients, while keeping the diversity and avoiding overtraining the ANN due the presence of similar samples. The proposed method is based on the calculation of the angle between two vectors, each one representing one input of the neural network. When the angle formed among samples is smaller than a defined threshold only one input is accepted for the training. The accepted inputs are scattered throughout the sample space. Tidal records are used to demonstrate the proposed method. The results of a cross-validation show that with few inputs the quality of the outputs is not accurate and depends on the selection of the first sample, but as the number of inputs increases the accuracy is improved and differences among the scenarios with a different starting sample have and important reduction. A comparison with the K-means clustering algorithm shows that for this application the proposed method with a smaller number of samples is producing a more accurate network.

  5. Novel joint selection methods can reduce sample size for rheumatoid arthritis clinical trials with ultrasound endpoints.

    Science.gov (United States)

    Allen, John C; Thumboo, Julian; Lye, Weng Kit; Conaghan, Philip G; Chew, Li-Ching; Tan, York Kiat

    2018-03-01

    To determine whether novel methods of selecting joints through (i) ultrasonography (individualized-ultrasound [IUS] method), or (ii) ultrasonography and clinical examination (individualized-composite-ultrasound [ICUS] method) translate into smaller rheumatoid arthritis (RA) clinical trial sample sizes when compared to existing methods utilizing predetermined joint sites for ultrasonography. Cohen's effect size (ES) was estimated (ES^) and a 95% CI (ES^L, ES^U) calculated on a mean change in 3-month total inflammatory score for each method. Corresponding 95% CIs [nL(ES^U), nU(ES^L)] were obtained on a post hoc sample size reflecting the uncertainty in ES^. Sample size calculations were based on a one-sample t-test as the patient numbers needed to provide 80% power at α = 0.05 to reject a null hypothesis H 0 : ES = 0 versus alternative hypotheses H 1 : ES = ES^, ES = ES^L and ES = ES^U. We aimed to provide point and interval estimates on projected sample sizes for future studies reflecting the uncertainty in our study ES^S. Twenty-four treated RA patients were followed up for 3 months. Utilizing the 12-joint approach and existing methods, the post hoc sample size (95% CI) was 22 (10-245). Corresponding sample sizes using ICUS and IUS were 11 (7-40) and 11 (6-38), respectively. Utilizing a seven-joint approach, the corresponding sample sizes using ICUS and IUS methods were nine (6-24) and 11 (6-35), respectively. Our pilot study suggests that sample size for RA clinical trials with ultrasound endpoints may be reduced using the novel methods, providing justification for larger studies to confirm these observations. © 2017 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

  6. Effect of field view size and lighting on unique-hue selection using Natural Color System object colors.

    Science.gov (United States)

    Shamey, Renzo; Zubair, Muhammad; Cheema, Hammad

    2015-08-01

    The aim of this study was twofold, first to determine the effect of field view size and second of illumination conditions on the selection of unique hue samples (UHs: R, Y, G and B) from two rotatable trays, each containing forty highly chromatic Natural Color System (NCS) samples, on one tray corresponding to 1.4° and on the other to 5.7° field of view size. UH selections were made by 25 color-normal observers who repeated assessments three times with a gap of at least 24h between trials. Observers separately assessed UHs under four illumination conditions simulating illuminants D65, A, F2 and F11. An apparent hue shift (statistically significant for UR) was noted for UH selections at 5.7° field of view compared to those at 1.4°. Observers' overall variability was found to be higher for UH stimuli selections at the larger field of view. Intra-observer variability was found to be approximately 18.7% of inter-observer variability in selection of samples for both sample sizes. The highest intra-observer variability was under simulated illuminant D65, followed by A, F11, and F2. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. A GMM-Based Test for Normal Disturbances of the Heckman Sample Selection Model

    Directory of Open Access Journals (Sweden)

    Michael Pfaffermayr

    2014-10-01

    Full Text Available The Heckman sample selection model relies on the assumption of normal and homoskedastic disturbances. However, before considering more general, alternative semiparametric models that do not need the normality assumption, it seems useful to test this assumption. Following Meijer and Wansbeek (2007, the present contribution derives a GMM-based pseudo-score LM test on whether the third and fourth moments of the disturbances of the outcome equation of the Heckman model conform to those implied by the truncated normal distribution. The test is easy to calculate and in Monte Carlo simulations it shows good performance for sample sizes of 1000 or larger.

  8. Comparison of dechlorination rates for field DNAPL vs synthetic samples: effect of sample matrix

    Science.gov (United States)

    O'Carroll, D. M.; Sakulchaicharoen, N.; Herrera, J. E.

    2015-12-01

    Nanometals have received significant attention in recent years due to their ability to rapidly destroy numerous priority source zone contaminants in controlled laboratory studies. This has led to great optimism surrounding nanometal particle injection for insitu remediation. Reported dechlorination rates vary widely among different investigators. These differences have been ascribed to differences in the iron types (granular, micro, or nano-sized iron), matrix solution chemistry and the morphology of the nZVI surface. Among these, the effects of solution chemistry on rates of reductive dechlorination of various chlorinated compounds have been investigated in several short-term laboratory studies. Variables investigated include the effect of anions or groundwater solutes such as SO4-2, Cl-, NO3-, pH, natural organic matters (NOM), surfactant, and humic acid on dechlorination reaction of various chlorinated compounds such as TCE, carbon tetrachloride (CT), and chloroform (CF). These studies have normally centered on the assessment of nZVI reactivity toward dechlorination of an isolated individual contaminant spiked into a ground water sample under ideal conditions, with limited work conducted using real field samples. In this work, the DNAPL used for the dechlorination study was obtained from a contaminatied site. This approach was selected to adequately simulate a condition where the nZVI suspension was in direct contact with DNAPL and to isolate the dechlorination activity shown by the nZVI from the groundwater matrix effects. An ideal system "synthetic DNAPL" composed of a mixture of chlorinated compounds mimicking the composition of the actual DNAPL was also dechlorinated to evaluate the DNAPL "matrix effect" on NZVI dechlorination activity. This approach allowed us to evaluate the effect of the presence of different types of organic compounds (volatile fatty acids and humic acids) found in the actual DNAPL on nZVI dechlorination activity. This presentation will

  9. Multiwavelength diagnostics of accretion in an X-ray selected sample of CTTSs

    Science.gov (United States)

    Curran, R. L.; Argiroffi, C.; Sacco, G. G.; Orlando, S.; Peres, G.; Reale, F.; Maggio, A.

    2011-02-01

    Context. High resolution X-ray spectroscopy has revealed soft X-rays from high density plasma in classical T Tauri stars (CTTSs), probably arising from the accretion shock region. However, the mass accretion rates derived from the X-ray observations are consistently lower than those derived from UV/optical/NIR studies. Aims: We aim to test the hypothesis that the high density soft X-ray emission originates from accretion by analysing, in a homogeneous manner, optical accretion indicators for an X-ray selected sample of CTTSs. Methods: We analyse optical spectra of the X-ray selected sample of CTTSs and calculate the accretion rates based on measuring the Hα, Hβ, Hγ, He ii 4686 Å, He i 5016 Å, He i 5876 Å, O i 6300 Å, and He i 6678 Å equivalent widths. In addition, we also calculate the accretion rates based on the full width at 10% maximum of the Hα line. The different optical tracers of accretion are compared and discussed. The derived accretion rates are then compared to the accretion rates derived from the X-ray spectroscopy. Results: We find that, for each CTTS in our sample, the different optical tracers predict mass-accretion rates that agree within the errors, albeit with a spread of ≈ 1 order of magnitude. Typically, mass-accretion rates derived from Hα and He i 5876 Å are larger than those derived from Hβ, Hγ, and O i. In addition, the Hα full width at 10%, whilst a good indicator of accretion, may not accurately measure the mass-accretion rate. When the optical mass-accretion rates are compared to the X-ray derived mass-accretion rates, we find that: a) the latter are always lower (but by varying amounts); b) the latter range within a factor of ≈ 2 around 2 × 10-10 M⊙ yr-1, despite the former spanning a range of ≈ 3 orders of magnitude. We suggest that the systematic underestimate of the X-ray derived mass-accretion rates could depend on the density distribution inside the accretion streams, where the densest part of the stream is

  10. Forecasting Urban Air Quality via a Back-Propagation Neural Network and a Selection Sample Rule

    Directory of Open Access Journals (Sweden)

    Yonghong Liu

    2015-07-01

    Full Text Available In this paper, based on a sample selection rule and a Back Propagation (BP neural network, a new model of forecasting daily SO2, NO2, and PM10 concentration in seven sites of Guangzhou was developed using data from January 2006 to April 2012. A meteorological similarity principle was applied in the development of the sample selection rule. The key meteorological factors influencing SO2, NO2, and PM10 daily concentrations as well as weight matrices and threshold matrices were determined. A basic model was then developed based on the improved BP neural network. Improving the basic model, identification of the factor variation consistency was added in the rule, and seven sets of sensitivity experiments in one of the seven sites were conducted to obtain the selected model. A comparison of the basic model from May 2011 to April 2012 in one site showed that the selected model for PM10 displayed better forecasting performance, with Mean Absolute Percentage Error (MAPE values decreasing by 4% and R2 values increasing from 0.53 to 0.68. Evaluations conducted at the six other sites revealed a similar performance. On the whole, the analysis showed that the models presented here could provide local authorities with reliable and precise predictions and alarms about air quality if used at an operational scale.

  11. Rapid screening of selective serotonin re-uptake inhibitors in urine samples using solid-phase microextraction gas chromatography-mass spectrometry.

    Science.gov (United States)

    Salgado-Petinal, Carmen; Lamas, J Pablo; Garcia-Jares, Carmen; Llompart, Maria; Cela, Rafael

    2005-07-01

    In this paper a solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) method is proposed for a rapid analysis of some frequently prescribed selective serotonin re-uptake inhibitors (SSRI)-venlafaxine, fluvoxamine, mirtazapine, fluoxetine, citalopram, and sertraline-in urine samples. The SPME-based method enables simultaneous determination of the target SSRI after simple in-situ derivatization of some of the target compounds. Calibration curves in water and in urine were validated and statistically compared. This revealed the absence of matrix effect and, in consequence, the possibility of quantifying SSRI in urine samples by external water calibration. Intra-day and inter-day precision was satisfactory for all the target compounds (relative standard deviation, RSD, detection limits achieved were detected and tentatively identified.

  12. The moderating effects of sample type as evidence of the effects of faking on personality scale correlations and factor structure

    Directory of Open Access Journals (Sweden)

    KEVIN M. BRADLEY

    2006-09-01

    Full Text Available Motivational differences as a function of sample type (applicants versus incumbents have frequently been suspected of causing meaningful differences in the psychometric properties of personality inventories due to the effects of faking. In this quantitative review, correlations among the Big Five personality constructs were estimated and sample type was examined as a potential moderator of the personality construct inter-correlations. The resulting subgroup meta-analytic correlation matrices were factor-analyzed, and the second order factor solutions for job incumbents and job applicants were compared. Results of the meta-analyses indicate frequent, but small moderating effects. The second order factor analyses indicated that the observed moderation had little effect on the congruence of factor loadings. Together, the results are consistent with the position that faking is of little practical consequence in selection settings.

  13. Selection effects on GRB spectral-energy correlations

    International Nuclear Information System (INIS)

    Nava, Lara; Ghirlanda, Giancarlo; Ghisellini, Gabriele

    2009-01-01

    Instrumental selection effects can act upon the estimates of the peak energy E peak obs , the fluence F and the peak flux P of GRBs. If this were the case, then the correlations involving the corresponding rest frame quantities (i.e. E peak , E obs and the peak luminosity L iso ) would be questioned. We estimated, as a function of E peak obs , the minimum peak flux necessary to trigger a GRB and the minimum fluence a burst must have to determine the value of E peak obs by considering different instruments (BATSE, Swift, BeppoSAX). We find that the latter dominates over the former. We then study the E peak obs -fluence (and flux) correlation in the observer plane. GRBs with redshift show well defined E peak obs -F and E peak obs -P correlations: in this planes the selection effects are present, but do not determine the found correlations. This is not true for Swift GRBs with redshift, for which the spectral analysis threshold does affect their distribution in the observer planes. Extending the sample to GRBs without z, we still find a significant E peak obs -F correlation, although with a larger scatter than that defined by GRBs with redshift. We find that 6% are outliers of the Amati correlation. The E peak obs -P correlation of GRBs with or without redshift is the same and no outlier is found among bursts without redshift.

  14. The Complete Local Volume Groups Sample - I. Sample selection and X-ray properties of the high-richness subsample

    Science.gov (United States)

    O'Sullivan, Ewan; Ponman, Trevor J.; Kolokythas, Konstantinos; Raychaudhury, Somak; Babul, Arif; Vrtilek, Jan M.; David, Laurence P.; Giacintucci, Simona; Gitti, Myriam; Haines, Chris P.

    2017-12-01

    We present the Complete Local-Volume Groups Sample (CLoGS), a statistically complete optically selected sample of 53 groups within 80 Mpc. Our goal is to combine X-ray, radio and optical data to investigate the relationship between member galaxies, their active nuclei and the hot intra-group medium (IGM). We describe sample selection, define a 26-group high-richness subsample of groups containing at least four optically bright (log LB ≥ 10.2 LB⊙) galaxies, and report the results of XMM-Newton and Chandra observations of these systems. We find that 14 of the 26 groups are X-ray bright, possessing a group-scale IGM extending at least 65 kpc and with luminosity >1041 erg s-1, while a further three groups host smaller galaxy-scale gas haloes. The X-ray bright groups have masses in the range M500 ≃ 0.5-5 × 1013 M⊙, based on system temperatures of 0.4-1.4 keV, and X-ray luminosities in the range 2-200 × 1041 erg s-1. We find that ∼53-65 per cent of the X-ray bright groups have cool cores, a somewhat lower fraction than found by previous archival surveys. Approximately 30 per cent of the X-ray bright groups show evidence of recent dynamical interactions (mergers or sloshing), and ∼35 per cent of their dominant early-type galaxies host active galactic nuclei with radio jets. We find no groups with unusually high central entropies, as predicted by some simulations, and confirm that CLoGS is in principle capable of detecting such systems. We identify three previously unrecognized groups, and find that they are either faint (LX, R500 < 1042 erg s-1) with no concentrated cool core, or highly disturbed. This leads us to suggest that ∼20 per cent of X-ray bright groups in the local universe may still be unidentified.

  15. A novel variable selection approach that iteratively optimizes variable space using weighted binary matrix sampling.

    Science.gov (United States)

    Deng, Bai-chuan; Yun, Yong-huan; Liang, Yi-zeng; Yi, Lun-zhao

    2014-10-07

    In this study, a new optimization algorithm called the Variable Iterative Space Shrinkage Approach (VISSA) that is based on the idea of model population analysis (MPA) is proposed for variable selection. Unlike most of the existing optimization methods for variable selection, VISSA statistically evaluates the performance of variable space in each step of optimization. Weighted binary matrix sampling (WBMS) is proposed to generate sub-models that span the variable subspace. Two rules are highlighted during the optimization procedure. First, the variable space shrinks in each step. Second, the new variable space outperforms the previous one. The second rule, which is rarely satisfied in most of the existing methods, is the core of the VISSA strategy. Compared with some promising variable selection methods such as competitive adaptive reweighted sampling (CARS), Monte Carlo uninformative variable elimination (MCUVE) and iteratively retaining informative variables (IRIV), VISSA showed better prediction ability for the calibration of NIR data. In addition, VISSA is user-friendly; only a few insensitive parameters are needed, and the program terminates automatically without any additional conditions. The Matlab codes for implementing VISSA are freely available on the website: https://sourceforge.net/projects/multivariateanalysis/files/VISSA/.

  16. Microstructure selection in thin-sample directional solidification of an Al-Cu alloy: In situ X-ray imaging and phase-field simulations

    International Nuclear Information System (INIS)

    Clarke, A. J.; Tourret, D.; Song, Y.; Imhoff, S. D.; Gibbs, P. J.

    2017-01-01

    We study microstructure selection during during directional solidification of a thin metallic sample. We combine in situ X-ray radiography of a dilute Al-Cu alloy solidification experiments with three-dimensional phase-field simulations. Here we explore a range of temperature gradient G and growth velocity V and build a microstructure selection map for this alloy. We investigate the selection of the primary dendritic spacing Λ and tip radius ρ. While ρ shows a good agreement between experimental measurements and dendrite growth theory, with ρ~V"-"1"/"2, Λ is observed to increase with V (∂Λ/∂V > 0), in apparent disagreement with classical scaling laws for primary dendritic spacing, which predict that ∂Λ/∂V<0. We show through simulations that this trend inversion for Λ(V) is due to liquid convection in our experiments, despite the thin sample configuration. We use a classical diffusion boundary-layer approximation to semi-quantitatively incorporate the effect of liquid convection into phase-field simulations. This approximation is implemented by assuming complete solute mixing outside a purely diffusive zone of constant thickness that surrounds the solid-liquid interface. This simple method enables us to quantitatively match experimental measurements of the planar morphological instability threshold and primary spacings over an order of magnitude in V. Lastly, we explain the observed inversion of ∂Λ/∂V by a combination of slow transient dynamics of microstructural homogenization and the influence of the sample thickness.

  17. Effect of Caraway Extract on the Performance of Selective Attention and Cognitive Flexibility

    Directory of Open Access Journals (Sweden)

    Ziba Barghi-Irani

    2014-09-01

    Full Text Available Background: This trial study is conducted in the field of psychopharmacology aiming to examine psychological effects of caraway. Materials and Methods: The sample under study consists of two groups including experimental (N=22 and control (N=28; both groups were identical in terms of demographic characteristics. The subjects participated voluntarily in the study; they were placed into experimental and control groups by random selection. The evaluation of attention function test was carried out by computerized Stroop effect test. Results: The results from analysis of covariance statistical test (ANCOVA showed that taking caraway with an effective dose may increase functions of selective attention, response inhibition ability as well as cognitive flexibility and change (p<0.005. Conclusion: Taking advantage of positive effects of caraway extract, it may be used as one of the herbal medicine in treating stress and increasing different attention functions

  18. 40 CFR Appendix Xi to Part 86 - Sampling Plans for Selective Enforcement Auditing of Light-Duty Vehicles

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Sampling Plans for Selective Enforcement Auditing of Light-Duty Vehicles XI Appendix XI to Part 86 Protection of Environment ENVIRONMENTAL... Enforcement Auditing of Light-Duty Vehicles 40% AQL Table 1—Sampling Plan Code Letter Annual sales of...

  19. 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.

  20. K-selection, α-selection, effectiveness, and tolerance in competition ...

    Indian Academy of Sciences (India)

    selection, effectiveness, and tolerance in ... Evolutionary Biology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, P.O. Box No. 6436, Jakkur, Bangalore 560 064, India; Poornaprajna ...

  1. 40 CFR Appendix X to Part 86 - Sampling Plans for Selective Enforcement Auditing of Heavy-Duty Engines and Light-Duty Trucks

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Sampling Plans for Selective Enforcement Auditing of Heavy-Duty Engines and Light-Duty Trucks X Appendix X to Part 86 Protection of... Plans for Selective Enforcement Auditing of Heavy-Duty Engines and Light-Duty Trucks Table 1—Sampling...

  2. The perils of straying from protocol: sampling bias and interviewer effects.

    Directory of Open Access Journals (Sweden)

    Carrie J Ngongo

    Full Text Available Fidelity to research protocol is critical. In a contingent valuation study in an informal urban settlement in Nairobi, Kenya, participants responded differently to the three trained interviewers. Interviewer effects were present during the survey pilot, then magnified at the start of the main survey after a seemingly slight adaptation of the survey sampling protocol allowed interviewers to speak with the "closest neighbor" in the event that no one was home at a selected household. This slight degree of interviewer choice led to inferred sampling bias. Multinomial logistic regression and post-estimation tests revealed that the three interviewers' samples differed significantly from one another according to six demographic characteristics. The two female interviewers were 2.8 and 7.7 times less likely to talk with respondents of low socio-economic status than the male interviewer. Systematic error renders it impossible to determine which of the survey responses might be "correct." This experience demonstrates why researchers must take care to strictly follow sampling protocols, consistently train interviewers, and monitor responses by interview to ensure similarity between interviewers' groups and produce unbiased estimates of the parameters of interest.

  3. Spot the difference. Impact of different selection criteria on observed properties of passive galaxies in zCOSMOS-20k sample

    Science.gov (United States)

    Moresco, M.; Pozzetti, L.; Cimatti, A.; Zamorani, G.; Bolzonella, M.; Lamareille, F.; Mignoli, M.; Zucca, E.; Lilly, S. J.; Carollo, C. M.; Contini, T.; Kneib, J.-P.; Le Fèvre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Bongiorno, A.; Caputi, K.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovač, K.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Pelló, R.; Peng, Y.; Perez-Montero, E.; Presotto, V.; Silverman, J. D.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Barnes, L.; Bordoloi, R.; Cappi, A.; Diener, C.; Koekemoer, A. M.; Le Floc'h, E.; López-Sanjuan, C.; McCracken, H. J.; Nair, P.; Oesch, P.; Scarlata, C.; Scoville, N.; Welikala, N.

    2013-10-01

    Aims: We present the analysis of photometric, spectroscopic, and morphological properties for differently selected samples of passive galaxies up to z = 1 extracted from the zCOSMOS-20k spectroscopic survey. This analysis intends toexplore the dependence of galaxy properties on the selection criterion adopted, study the degree of contamination due to star-forming outliers, and provide a comparison between different commonly used selection criteria. This work is a first step to fully investigating the selection effects of passive galaxies for future massive surveys such as Euclid. Methods: We extracted from the zCOSMOS-20k catalog six different samples of passive galaxies, based on morphology (3336 "morphological" early-type galaxies), optical colors (4889 "red-sequence" galaxies and 4882 "red UVJ" galaxies), specific star-formation rate (2937 "quiescent" galaxies), a best fit to the observed spectral energy distribution (2603 "red SED" galaxies), and a criterion that combines morphological, spectroscopic, and photometric information (1530 "red & passive early-type galaxies"). For all the samples, we studied optical and infrared colors, morphological properties, specific star-formation rates (SFRs), and the equivalent widths of the residual emission lines; this analysis was performed as a function of redshift and stellar mass to inspect further possible dependencies. Results: We find that each passive galaxy sample displays a certain level of contamination due to blue/star-forming/nonpassive outliers. The morphological sample is the one that presents the higher percentage of contamination, with ~12-65% (depending on the mass range) of galaxies not located in the red sequence, ~25-80% of galaxies with a specific SFR up to ~25 times higher than the adopted definition of passive, and significant emission lines found in the median stacked spectra, at least for log (M/M⊙) contamination in color 10.25, very limited tails in sSFR, a median value ~20% higher than the

  4. Concurrent and Longitudinal Associations Among Temperament, Parental Feeding Styles, and Selective Eating in a Preschool Sample.

    Science.gov (United States)

    Kidwell, Katherine M; Kozikowski, Chelsea; Roth, Taylor; Lundahl, Alyssa; Nelson, Timothy D

    2018-06-01

    To examine the associations among negative/reactive temperament, feeding styles, and selective eating in a sample of preschoolers because preschool eating behaviors likely have lasting implications for children's health. A community sample of preschoolers aged 3-5 years (M = 4.49 years, 49.5% female, 75.7% European American) in the Midwest of the United States was recruited to participate in the study (N = 297). Parents completed measures of temperament and feeding styles at two time points 6 months apart. A series of regressions indicated that children who had temperaments high in negative affectivity were significantly more likely to experience instrumental and emotional feeding styles. They were also significantly more likely to be selective eaters. These associations were present when examined both concurrently and after 6 months. This study provides a novel investigation of child temperament and eating behaviors, allowing for a better understanding of how negative affectivity is associated with instrumental feeding, emotional feeding, and selective eating. These results inform interventions to improve child health.

  5. Correlations Between Life-Detection Techniques and Implications for Sampling Site Selection in Planetary Analog Missions

    Science.gov (United States)

    Gentry, Diana M.; Amador, Elena S.; Cable, Morgan L.; Chaudry, Nosheen; Cullen, Thomas; Jacobsen, Malene B.; Murukesan, Gayathri; Schwieterman, Edward W.; Stevens, Adam H.; Stockton, Amanda; Tan, George; Yin, Chang; Cullen, David C.; Geppert, Wolf

    2017-10-01

    We conducted an analog sampling expedition under simulated mission constraints to areas dominated by basaltic tephra of the Eldfell and Fimmvörðuháls lava fields (Iceland). Sites were selected to be "homogeneous" at a coarse remote sensing resolution (10-100 m) in apparent color, morphology, moisture, and grain size, with best-effort realism in numbers of locations and replicates. Three different biomarker assays (counting of nucleic-acid-stained cells via fluorescent microscopy, a luciferin/luciferase assay for adenosine triphosphate, and quantitative polymerase chain reaction (qPCR) to detect DNA associated with bacteria, archaea, and fungi) were characterized at four nested spatial scales (1 m, 10 m, 100 m, and >1 km) by using five common metrics for sample site representativeness (sample mean variance, group F tests, pairwise t tests, and the distribution-free rank sum H and u tests). Correlations between all assays were characterized with Spearman's rank test. The bioluminescence assay showed the most variance across the sites, followed by qPCR for bacterial and archaeal DNA; these results could not be considered representative at the finest resolution tested (1 m). Cell concentration and fungal DNA also had significant local variation, but they were homogeneous over scales of >1 km. These results show that the selection of life detection assays and the number, distribution, and location of sampling sites in a low biomass environment with limited a priori characterization can yield both contrasting and complementary results, and that their interdependence must be given due consideration to maximize science return in future biomarker sampling expeditions.

  6. Concentration of ions in selected bottled water samples sold in Malaysia

    Science.gov (United States)

    Aris, Ahmad Zaharin; Kam, Ryan Chuan Yang; Lim, Ai Phing; Praveena, Sarva Mangala

    2013-03-01

    Many consumers around the world, including Malaysians, have turned to bottled water as their main source of drinking water. The aim of this study is to determine the physical and chemical properties of bottled water samples sold in Selangor, Malaysia. A total of 20 bottled water brands consisting of `natural mineral (NM)' and `packaged drinking (PD)' types were randomly collected and analyzed for their physical-chemical characteristics: hydrogen ion concentration (pH), electrical conductivity (EC) and total dissolved solids (TDS), selected major ions: calcium (Ca), potassium (K), magnesium (Mg) and sodium (Na), and minor trace constituents: copper (Cu) and zinc (Zn) to ascertain their suitability for human consumption. The results obtained were compared with guideline values recommended by World Health Organization (WHO) and Malaysian Ministry of Health (MMOH), respectively. It was found that all bottled water samples were in accordance with the guidelines set by WHO and MMOH except for one sample (D3) which was below the pH limit of 6.5. Both NM and PD bottled water were dominated by Na + K > Ca > Mg. Low values for EC and TDS in the bottled water samples showed that water was deficient in essential elements, likely an indication that these were removed by water treatment. Minerals like major ions were present in very low concentrations which could pose a risk to individuals who consume this water on a regular basis. Generally, the overall quality of the supplied bottled water was in accordance to standards and guidelines set by WHO and MMOH and safe for consumption.

  7. A quantitative method to detect explosives and selected semivolatiles in soil samples by Fourier transform infrared spectroscopy

    International Nuclear Information System (INIS)

    Clapper-Gowdy, M.; Dermirgian, J.; Robitaille, G.

    1995-01-01

    This paper describes a novel Fourier transform infrared (FTIR) spectroscopic method that can be used to rapidly screen soil samples from potentially hazardous waste sites. Samples are heated in a thermal desorption unit and the resultant vapors are collected and analyzed in a long-path gas cell mounted in a FTIR. Laboratory analysis of a soil sample by FTIR takes approximately 10 minutes. This method has been developed to identify and quantify microgram concentrations of explosives in soil samples and is directly applicable to the detection of selected volatile organics, semivolatile organics, and pesticides

  8. Effects of sample size and sampling frequency on studies of brown bear home ranges and habitat use

    Science.gov (United States)

    Arthur, Steve M.; Schwartz, Charles C.

    1999-01-01

    We equipped 9 brown bears (Ursus arctos) on the Kenai Peninsula, Alaska, with collars containing both conventional very-high-frequency (VHF) transmitters and global positioning system (GPS) receivers programmed to determine an animal's position at 5.75-hr intervals. We calculated minimum convex polygon (MCP) and fixed and adaptive kernel home ranges for randomly-selected subsets of the GPS data to examine the effects of sample size on accuracy and precision of home range estimates. We also compared results obtained by weekly aerial radiotracking versus more frequent GPS locations to test for biases in conventional radiotracking data. Home ranges based on the MCP were 20-606 km2 (x = 201) for aerial radiotracking data (n = 12-16 locations/bear) and 116-1,505 km2 (x = 522) for the complete GPS data sets (n = 245-466 locations/bear). Fixed kernel home ranges were 34-955 km2 (x = 224) for radiotracking data and 16-130 km2 (x = 60) for the GPS data. Differences between means for radiotracking and GPS data were due primarily to the larger samples provided by the GPS data. Means did not differ between radiotracking data and equivalent-sized subsets of GPS data (P > 0.10). For the MCP, home range area increased and variability decreased asymptotically with number of locations. For the kernel models, both area and variability decreased with increasing sample size. Simulations suggested that the MCP and kernel models required >60 and >80 locations, respectively, for estimates to be both accurate (change in area bears. Our results suggest that the usefulness of conventional radiotracking data may be limited by potential biases and variability due to small samples. Investigators that use home range estimates in statistical tests should consider the effects of variability of those estimates. Use of GPS-equipped collars can facilitate obtaining larger samples of unbiased data and improve accuracy and precision of home range estimates.

  9. The ATLAS3D project - I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria

    Science.gov (United States)

    Cappellari, Michele; Emsellem, Eric; Krajnović, Davor; McDermid, Richard M.; Scott, Nicholas; Verdoes Kleijn, G. A.; Young, Lisa M.; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Serra, Paolo; Weijmans, Anne-Marie

    2011-05-01

    The ATLAS3D project is a multiwavelength survey combined with a theoretical modelling effort. The observations span from the radio to the millimetre and optical, and provide multicolour imaging, two-dimensional kinematics of the atomic (H I), molecular (CO) and ionized gas (Hβ, [O III] and [N I]), together with the kinematics and population of the stars (Hβ, Fe5015 and Mg b), for a carefully selected, volume-limited (1.16 × 105 Mpc3) sample of 260 early-type (elliptical E and lenticular S0) galaxies (ETGs). The models include semi-analytic, N-body binary mergers and cosmological simulations of galaxy formation. Here we present the science goals for the project and introduce the galaxy sample and the selection criteria. The sample consists of nearby (D 15°) morphologically selected ETGs extracted from a parent sample of 871 galaxies (8 per cent E, 22 per cent S0 and 70 per cent spirals) brighter than MK statistically representative of the nearby galaxy population. We present the size-luminosity relation for the spirals and ETGs and show that the ETGs in the ATLAS3D sample define a tight red sequence in a colour-magnitude diagram, with few objects in the transition from the blue cloud. We describe the strategy of the SAURON integral field observations and the extraction of the stellar kinematics with the pPXF method. We find typical 1σ errors of ΔV≈ 6 km s-1, Δσ≈ 7 km s-1, Δh3≈Δh4≈ 0.03 in the mean velocity, the velocity dispersion and Gauss-Hermite (GH) moments for galaxies with effective dispersion σe≳ 120 km s-1. For galaxies with lower σe (≈40 per cent of the sample) the GH moments are gradually penalized by pPXF towards zero to suppress the noise produced by the spectral undersampling and only V and σ can be measured. We give an overview of the characteristics of the other main data sets already available for our sample and of the ongoing modelling projects.

  10. Extraction and Analysis of Strontium in Water Sample Using a Sr2+ Selective Polymer as the Absorbent Phase

    Directory of Open Access Journals (Sweden)

    Rongjian Ying

    2015-01-01

    Full Text Available A kind of Sr2+ selective resin was applied as an absorption phase to extract Sr2+ ion from an aqueous solution, and the amount of Sr2+ was determined using inductively coupled plasma optical emission spectrometer. Factors, including absorption time, temperature, stirring rate, salt-out effect, desorption, and the pH of the aqueous solution, were investigated to optimize the absorption efficiency of Sr2+. Foreign ions were examined to observe their effects on the absorption behavior of Sr2+. The optimum condition was absorption time at 20 min, pH of aqueous solution 7, temperature of 35°C, and 600 rpm stirring rate. A 10 mL solution of 0.1 mol/L HCl is used as the desorption agent. The linear range of Sr2+ concentrations from 50 to 1200 μg/L was investigated with the slope of 183 μg/L. The limit of detection was 21 μg/L with 4.23% relative standard deviation. The correlation coefficient was found to be 0.9947. Under the optimized conditions, the concentrations of Sr2+ in four water samples were detected by the developed method. We propose that this method effectively extracts strontium ion from environmental water samples.

  11. A Virtual Observatory Census to Address Dwarfs Origins (AVOCADO). I. Science goals, sample selection, and analysis tools

    Science.gov (United States)

    Sánchez-Janssen, R.; Amorín, R.; García-Vargas, M.; Gomes, J. M.; Huertas-Company, M.; Jiménez-Esteban, F.; Mollá, M.; Papaderos, P.; Pérez-Montero, E.; Rodrigo, C.; Sánchez Almeida, J.; Solano, E.

    2013-06-01

    Context. Even though they are by far the most abundant of all galaxy types, the detailed properties of dwarf galaxies are still only poorly characterised - especially because of the observational challenge that their intrinsic faintness and weak clustering properties represent. Aims: AVOCADO aims at establishing firm conclusions on the formation and evolution of dwarf galaxies by constructing and analysing a homogeneous, multiwavelength dataset for a statistically significant sample of approximately 6500 nearby dwarfs (Mi - 5 log h100 > - 18 mag). The sample is selected to lie within the 20 < D < 60 h100-1 Mpc volume covered by the SDSS-DR7 footprint, and is thus volume-limited for Mi - 5 log h100 < -16 mag dwarfs - but includes ≈1500 fainter systems. We will investigate the roles of mass and environment in determining the current properties of the different dwarf morphological types - including their structure, their star formation activity, their chemical enrichment history, and a breakdown of their stellar, dust, and gas content. Methods: We present the sample selection criteria and describe the suite of analysis tools, some of them developed in the framework of the Virtual Observatory. We use optical spectra and UV-to-NIR imaging of the dwarf sample to derive star formation rates, stellar masses, ages, and metallicities - which are supplemented with structural parameters that are used to classify them morphologically. This unique dataset, coupled with a detailed characterisation of each dwarf's environment, allows for a fully comprehensive investigation of their origins and enables us to track the (potential) evolutionary paths between the different dwarf types. Results: We characterise the local environment of all dwarfs in our sample, paying special attention to trends with current star formation activity. We find that virtually all quiescent dwarfs are located in the vicinity (projected distances ≲ 1.5 h100-1 Mpc) of ≳ L∗ companions, consistent with

  12. Automated sample plan selection for OPC modeling

    Science.gov (United States)

    Casati, Nathalie; Gabrani, Maria; Viswanathan, Ramya; Bayraktar, Zikri; Jaiswal, Om; DeMaris, David; Abdo, Amr Y.; Oberschmidt, James; Krause, Andreas

    2014-03-01

    It is desired to reduce the time required to produce metrology data for calibration of Optical Proximity Correction (OPC) models and also maintain or improve the quality of the data collected with regard to how well that data represents the types of patterns that occur in real circuit designs. Previous work based on clustering in geometry and/or image parameter space has shown some benefit over strictly manual or intuitive selection, but leads to arbitrary pattern exclusion or selection which may not be the best representation of the product. Forming the pattern selection as an optimization problem, which co-optimizes a number of objective functions reflecting modelers' insight and expertise, has shown to produce models with equivalent quality to the traditional plan of record (POR) set but in a less time.

  13. Studying hardness, workability and minimum bending radius in selectively laser-sintered Ti–6Al–4V alloy samples

    Science.gov (United States)

    Galkina, N. V.; Nosova, Y. A.; Balyakin, A. V.

    2018-03-01

    This research is relevant as it tries to improve the mechanical and service performance of the Ti–6Al–4V titanium alloy obtained by selective laser sintering. For that purpose, sintered samples were annealed at 750 and 850°C for an hour. Sintered and annealed samples were tested for hardness, workability and microstructure. It was found that incomplete annealing of selectively laser-sintered Ti–6Al–4V samples results in an insignificant reduction in hardness and ductility. Sintered and incompletely annealed samples had a hardness of 32..33 HRC, which is lower than the value of annealed parts specified in standards. Complete annealing at temperature 850°C reduces the hardness to 25 HRC and ductility by 15...20%. Incomplete annealing lowers the ductility factor from 0.08 to 0.06. Complete annealing lowers that value to 0.025. Complete annealing probably results in the embrittlement of sintered samples, perhaps due to their oxidation and hydrogenation in the air. Optical metallography showed lateral fractures in both sintered and annealed samples, which might be the reason why they had lower hardness and ductility.

  14. Selective mobility, segregation and neighbourhood effects

    Directory of Open Access Journals (Sweden)

    Sanne Boschman

    2015-11-01

    Full Text Available Introduction The residential neighbourhood is thought to affect residents because of presumed neighbourhood effects; the independent effects of a neighbourhood’s characteristics on the life chances of its residents. An enormous body of research has tried to measure neighbourhood effects, however, there are no clear conclusions on how much, if any, effect the neighbourhood has on its residents. There is non-random selection of people into neighbourhoods which causes a bias in the modelling of neighbourhood effects. Any correlation found between neighbourhood characteristics and individual outcomes might be explained by selection bias and can therefore not prove the existence of a causal neighbourhood effect. The question is; do poor neighbourhoods make people poor, or do poor people live in unattractive neighbourhoods because they cannot afford to live elsewhere (Cheshire, 2007. Therefore, insight in selection is important to gain more insight in neighbourhood effects (Van Ham and Manley, 2012. For neighbourhood effects research it is important to study selective mobility and neighbourhood choice and to combine neighbourhood effects research with neighbourhood selection research (Doff, 2010a; Van Ham and Manley, 2012; Van Ham et al., 2012; Galster, 2003; Hedman, 2011. The aim of this thesis therefore is to gain more insight in both the causes and the consequences of segregation and thus to study both individual residential mobility and neighbourhood selection and neighbourhood effects. Besides the neighbourhood effects literature, also the segregation literature will benefit from better insights in selective residential mobility because selective residential mobility is one of the main driving forces of segregation.  There are two main research questions for this thesis. Firstly, I try to give insight in selective mobility and neighbourhood choice and thus to study where, when and why which people move. What is the effect of personal

  15. Stability of selected volatile breath constituents in Tedlar, Kynar and Flexfilm sampling bags

    Science.gov (United States)

    Mochalski, Paweł; King, Julian; Unterkofler, Karl; Amann, Anton

    2016-01-01

    The stability of 41 selected breath constituents in three types of polymer sampling bags, Tedlar, Kynar, and Flexfilm, was investigated using solid phase microextraction and gas chromatography mass spectrometry. The tested molecular species belong to different chemical classes (hydrocarbons, ketones, aldehydes, aromatics, sulphurs, esters, terpenes, etc.) and exhibit close-to-breath low ppb levels (3–12 ppb) with the exception of isoprene, acetone and acetonitrile (106 ppb, 760 ppb, 42 ppb respectively). Stability tests comprised the background emission of contaminants, recovery from dry samples, recovery from humid samples (RH 80% at 37 °C), influence of the bag’s filling degree, and reusability. Findings yield evidence of the superiority of Tedlar bags over remaining polymers in terms of background emission, species stability (up to 7 days for dry samples), and reusability. Recoveries of species under study suffered from the presence of high amounts of water (losses up to 10%). However, only heavier volatiles, with molecular masses higher than 90, exhibited more pronounced losses (20–40%). The sample size (the degree of bag filling) was found to be one of the most important factors affecting the sample integrity. To sum up, it is recommended to store breath samples in pre-conditioned Tedlar bags up to 6 hours at the maximum possible filling volume. Among the remaining films, Kynar can be considered as an alternative to Tedlar; however, higher losses of compounds should be expected even within the first hours of storage. Due to the high background emission Flexfilm is not suitable for sampling and storage of samples for analyses aiming at volatiles at a low ppb level. PMID:23323261

  16. Semi-selective medium for Fusarium graminearum detection in seed samples

    Directory of Open Access Journals (Sweden)

    Marivane Segalin

    2010-12-01

    Full Text Available Fungi of the genus Fusarium cause a variety of difficult to control diseases in different crops, including winter cereals and maize. Among the species of this genus Fusarium graminearum deserves attention. The aim of this work was to develop a semi-selective medium to study this fungus. In several experiments, substrates for fungal growth were tested, including fungicides and antibiotics such as iprodiona, nystatin and triadimenol, and the antibacterial agents streptomycin and neomycin sulfate. Five seed samples of wheat, barley, oat, black beans and soybeans for F. graminearum detection by using the media Nash and Snyder agar (NSA, Segalin & Reis agar (SRA and one-quarter dextrose agar (1/4PDA; potato 50g; dextrose 5g and agar 20g, either unsupplemented or supplemented with various concentrations of the antimicrobial agents cited above. The selected components and concentrations (g.L-1 of the proposed medium, Segalin & Reis agar (SRA-FG, were: iprodiona 0.05; nystatin 0,025; triadimenol 0.015; neomycin sulfate 0.05; and streptomycin sulfate, 0.3 added of ¼ potato sucrose agar. In the isolation from seeds of cited plant species, the sensitivity of this medium was similar to that of NSA but with de advantage of maintaining the colony morphological aspects similar to those observed in potato-dextrose-agar medium.

  17. Synthesis of surface Cr (VI)-imprinted magnetic nanoparticles for selective dispersive solid-phase extraction and determination of Cr (VI) in water samples.

    Science.gov (United States)

    Qi, Xue; Gao, Shuang; Ding, Guosheng; Tang, An-Na

    2017-01-01

    A facile, rapid and selective magnetic dispersed solid-phase extraction (dSPE) method for the extraction and enrichment of Cr (VI) prior to flame atomic absorption spectrometry (AAS) was introduced. For highly selective and efficient extraction, magnetic Cr (VI)-imprinted nanoparticles (Fe 3 O 4 @ Cr (VI) IIPs) were prepared by hyphenating surface ion-imprinted with sol-gel techniques. In the preparation process, chromate (Cr(VI)) was used as the template ion; vinylimidazole and 3-aminopropyltriethoxysilane were selected as organic functional monomer and co-monomer respectively. Another reagent, methacryloxypropyltrimethoxysilane was adopted as coupling agent to form the stable covalent bonding between organic and inorganic phases. The effects of various parameters on the extraction efficiency, such as pH of sample solution, the amount of adsorbent, extraction time, the type and concentration of eluent were systematically investigated. Furthermore, the thermodynamic and kinetic properties of the adsorption process were studied to explore the internal adsorption mechanism. Under optimized conditions, the preconcentration factor, limit of detection and linear range of the established dSPE-AAS method for Cr (VI) were found to be 98, 0.29μgL -1 and 4-140μgL -1 , respectively. The developed method was also successfully applied to the analysis of Cr (VI) in different water samples with satisfactory results, proving its reliability and feasibility in real sample analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Biological sample collector

    Science.gov (United States)

    Murphy, Gloria A [French Camp, CA

    2010-09-07

    A biological sample collector is adapted to a collect several biological samples in a plurality of filter wells. A biological sample collector may comprise a manifold plate for mounting a filter plate thereon, the filter plate having a plurality of filter wells therein; a hollow slider for engaging and positioning a tube that slides therethrough; and a slide case within which the hollow slider travels to allow the tube to be aligned with a selected filter well of the plurality of filter wells, wherein when the tube is aligned with the selected filter well, the tube is pushed through the hollow slider and into the selected filter well to sealingly engage the selected filter well and to allow the tube to deposit a biological sample onto a filter in the bottom of the selected filter well. The biological sample collector may be portable.

  19. Testing the normality assumption in the sample selection model with an application to travel demand

    NARCIS (Netherlands)

    van der Klaauw, B.; Koning, R.H.

    2003-01-01

    In this article we introduce a test for the normality assumption in the sample selection model. The test is based on a flexible parametric specification of the density function of the error terms in the model. This specification follows a Hermite series with bivariate normality as a special case.

  20. Testing the normality assumption in the sample selection model with an application to travel demand

    NARCIS (Netherlands)

    van der Klauw, B.; Koning, R.H.

    In this article we introduce a test for the normality assumption in the sample selection model. The test is based on a flexible parametric specification of the density function of the error terms in the model. This specification follows a Hermite series with bivariate normality as a special case.

  1. The lack of selection bias in a snowball sampled case-control study on drug abuse.

    Science.gov (United States)

    Lopes, C S; Rodrigues, L C; Sichieri, R

    1996-12-01

    Friend controls in matched case-control studies can be a potential source of bias based on the assumption that friends are more likely to share exposure factors. This study evaluates the role of selection bias in a case-control study that used the snowball sampling method based on friendship for the selection of cases and controls. The cases selected fro the study were drug abusers located in the community. Exposure was defined by the presence of at least one psychiatric diagnosis. Psychiatric and drug abuse/dependence diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. Cases and controls were matched on sex, age and friendship. The measurement of selection bias was made through the comparison of the proportion of exposed controls selected by exposed cases (p1) with the proportion of exposed controls selected by unexposed cases (p2). If p1 = p2 then, selection bias should not occur. The observed distribution of the 185 matched pairs having at least one psychiatric disorder showed a p1 value of 0.52 and a p2 value of 0.51, indicating no selection bias in this study. Our findings support the idea that the use of friend controls can produce a valid basis for a case-control study.

  2. 40 CFR Appendix A to Subpart F of... - Sampling Plans for Selective Enforcement Auditing of Small Nonroad Engines

    Science.gov (United States)

    2010-07-01

    ... Enforcement Auditing of Small Nonroad Engines A Appendix A to Subpart F of Part 90 Protection of Environment...-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Selective Enforcement Auditing Pt. 90, Subpt. F, App. A Appendix A to Subpart F of Part 90—Sampling Plans for Selective Enforcement Auditing of Small Nonroad Engines...

  3. Antimicrobial Effectiveness of Selected Vranac Wines Against Six ...

    African Journals Online (AJOL)

    glucoside and. Folin - Ciocalteu`s phenol reagent were supplied from Sigma Chemical Co. (St Louis, Mo, USA); used reagents were of analytical quality. Wines samples. Selected Vranac wines from vintage 2009, made from autochthonic Vranac V.

  4. Local heterogeneity effects on small-sample worths

    International Nuclear Information System (INIS)

    Schaefer, R.W.

    1986-01-01

    One of the parameters usually measured in a fast reactor critical assembly is the reactivity associated with inserting a small sample of a material into the core (sample worth). Local heterogeneities introduced by the worth measurement techniques can have a significant effect on the sample worth. Unfortunately, the capability is lacking to model some of the heterogeneity effects associated with the experimental technique traditionally used at ANL (the radial tube technique). It has been suggested that these effects could account for a large portion of what remains of the longstanding central worth discrepancy. The purpose of this paper is to describe a large body of experimental data - most of which has never been reported - that shows the effect of radial tube-related local heterogeneities

  5. The Effect of Using a Proposed Teaching Strategy Based on the Selective Thinking on Students' Acquisition Concepts in Mathematics

    Science.gov (United States)

    Qudah, Ahmad Hassan

    2016-01-01

    This study aimed at identify the effect of using a proposed teaching strategy based on the selective thinking in acquire mathematical concepts by Classroom Teacher Students at Al- al- Bayt University, The sample of the study consisted of (74) students, equally distributed into a control group and an experimental group. The selective thinking…

  6. Simulation of sampling effects in FPAs

    Science.gov (United States)

    Cook, Thomas H.; Hall, Charles S.; Smith, Frederick G.; Rogne, Timothy J.

    1991-09-01

    The use of multiplexers and large focal plane arrays in advanced thermal imaging systems has drawn renewed attention to sampling and aliasing issues in imaging applications. As evidenced by discussions in a recent workshop, there is no clear consensus among experts whether aliasing in sensor designs can be readily tolerated, or must be avoided at all cost. Further, there is no straightforward, analytical method that can answer the question, particularly when considering image interpreters as different as humans and autonomous target recognizers (ATR). However, the means exist for investigating sampling and aliasing issues through computer simulation. The U.S. Army Tank-Automotive Command (TACOM) Thermal Image Model (TTIM) provides realistic sensor imagery that can be evaluated by both human observers and TRs. This paper briefly describes the history and current status of TTIM, explains the simulation of FPA sampling effects, presents validation results of the FPA sensor model, and demonstrates the utility of TTIM for investigating sampling effects in imagery.

  7. Effect of antimony oxide on magnesium vanadates for the selective oxidation of hydrogen sulfide to sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Li, K.T.; Chi, Z.H. [Department of Chemical Engineering, Tunghai University, ROC Taichung (Taiwan)

    2001-05-17

    The effect of antimony oxide addition to MgV{sub 2}O{sub 6} and Mg{sub 3}V{sub 2}O{sub 8} was studied in the selective oxidation of hydrogen sulfide to sulfur. Significant improvements in sulfur selectivity and yield were observed for the uncalcined mechanical mixtures of magnesium vanadates with {alpha}-Sb{sub 2}O{sub 4}. Calcination of the mechanical mixtures resulted in the much stronger synergy in catalytic activity and sulfur selectivity. For the uncalcined samples, XRD, TPR and XPS studies indicated that antimony reduction behaviors in the mechanical mixtures differed very much from those in {alpha}-Sb{sub 2}O{sub 4} alone, suggested that their selectivity improvements might be due to the interactions (probably oxygen transfer) between {alpha}-Sb{sub 2}O{sub 4} and magnesium vanadates. For the calcined samples, XRD results indicated that their better catalytic performances in H{sub 2}S oxidation were primarily attributed to the formation of VSbO{sub 4} compound from antimony oxide and magnesium vanadates.

  8. EFFECT OF RECRUITMENT, SELECTION AND MOTIVATION TO PERFORMANCE OF EMPLOYEES AT DATACOMM DIANGRAHA COMPANY

    Directory of Open Access Journals (Sweden)

    I Ketut R Sudiarditha

    2017-05-01

    Full Text Available In this study, the goal is to test empirically the effect of recruitment, selection and motivation of the employee performance at Datacomm Diangraha Company. The samples used were employees of Datacomm Diangraha especially the engineers with the total number of respondents was 126. The analysis used a linear regression, this research examines four variables: Recruitment (X1, Selection (X2 and Motivation (X3 as independent variables, and Performance employees (Y as the dependent variable. Partial test shows that the recruitment effect of 0175 (positive and significant on the performance. While the selection is also influenced significantly by 0347 on employee performance. And further motivation for 0295 was a significant influence on employee performance.Measurement model analysis in this study showed that all variables have met the criteria of validity and reliability, while at the structural model analysis shows that testing of hypotheses H1, H2, and H3 supports the hypothesis proposed. The resulting model of the independent variables and the effect on the dependent variable is Y = 16,408 + 0175 0347 X1 + X2 + X3 0295. The study concluded that the recruitment, selection and motivation affect the performance of employees with the results affect the performance of 95%, while 5% is determined by other variables.

  9. A novel knot selection method for the error-bounded B-spline curve fitting of sampling points in the measuring process

    International Nuclear Information System (INIS)

    Liang, Fusheng; Zhao, Ji; Ji, Shijun; Zhang, Bing; Fan, Cheng

    2017-01-01

    The B-spline curve has been widely used in the reconstruction of measurement data. The error-bounded sampling points reconstruction can be achieved by the knot addition method (KAM) based B-spline curve fitting. In KAM, the selection pattern of initial knot vector has been associated with the ultimate necessary number of knots. This paper provides a novel initial knots selection method to condense the knot vector required for the error-bounded B-spline curve fitting. The initial knots are determined by the distribution of features which include the chord length (arc length) and bending degree (curvature) contained in the discrete sampling points. Firstly, the sampling points are fitted into an approximate B-spline curve Gs with intensively uniform knot vector to substitute the description of the feature of the sampling points. The feature integral of Gs is built as a monotone increasing function in an analytic form. Then, the initial knots are selected according to the constant increment of the feature integral. After that, an iterative knot insertion (IKI) process starting from the initial knots is introduced to improve the fitting precision, and the ultimate knot vector for the error-bounded B-spline curve fitting is achieved. Lastly, two simulations and the measurement experiment are provided, and the results indicate that the proposed knot selection method can reduce the number of ultimate knots available. (paper)

  10. Determination of specific activity of americium and plutonium in selected environmental samples

    International Nuclear Information System (INIS)

    Trebunova, T.

    1999-01-01

    The aim of this work was development of method for determination of americium and plutonium in environmental samples. Developed method was evaluated on soil samples and after they was applied on selected samples of fishes (smoked mackerel, herring and fillet from Alaska hake). The method for separation of americium is based on liquid separation with Aliquate-336, precipitation with oxalic acid and using of chromatographic material TRU-Spec TM .The intervals of radiochemical yields were from 13.0% to 80.9% for plutonium-236 and from 10.5% to 100% for americium-241. Determined specific activities of plutonium-239,240 were from (2.3 ± 1.4) mBq/kg to (82 ± 29) mBq/kg, the specific activities of plutonium-238 were from (14.2 ± 3.7) mBq/kg to (708 ± 86) mBq/kg. The specific activities of americium-241 were from (1.4 ± 0.9) mBq/kg to (3360 ± 210) mBq/kg. The fishes from Baltic Sea as well as from North Sea show highest specific activities then fresh-water fishes from Slovakia. Therefore the monitoring of alpha radionuclides in foods imported from territories with nuclear testing is recommended

  11. EXPLORING THE DIVERSITY OF GROUPS AT 0.1 < z < 0.8 WITH X-RAY AND OPTICALLY SELECTED SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Connelly, J. L. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Wilman, David J.; Finoguenov, Alexis; Saglia, Roberto [Max Planck Institute for Extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., D-85741 Garching (Germany); Hou, Annie; Parker, Laura C.; Henderson, Robert D. E. [Department of Physics and Astronomy, McMaster University, Hamilton ON L8S4M1 (Canada); Mulchaey, John S. [Observatories of the Carnegie Institution, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); McGee, Sean L.; Balogh, Michael L. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Bower, Richard G. [Department of Physics, University of Durham, Durham DH1 3LE (United Kingdom)

    2012-09-10

    We present the global group properties of two samples of galaxy groups containing 39 high-quality X-ray-selected systems and 38 optically (spectroscopically) selected systems in coincident spatial regions at 0.12 < z < 0.79. The total mass range of the combined sample is {approx}(10{sup 12}-5) Multiplication-Sign 10{sup 14} M{sub Sun }. Only nine optical systems are associable with X-ray systems. We discuss the confusion inherent in the matching of both galaxies to extended X-ray emission and of X-ray emission to already identified optical systems. Extensive spectroscopy has been obtained and the resultant redshift catalog and group membership are provided here. X-ray, dynamical, and total stellar masses of the groups are also derived and presented. We explore the effects of utilizing different centers and applying three different kinds of radial cut to our systems: a constant cut of 1 Mpc and two r{sub 200} cuts, one based on the velocity dispersion of the system and the other on the X-ray emission. We find that an X-ray-based r{sub 200} results in less scatter in scaling relations and less dynamical complexity as evidenced by results of the Anderson-Darling and Dressler-Schectman tests, indicating that this radius tends to isolate the virialized part of the system. The constant and velocity dispersion based cuts can overestimate membership and can work to inflate velocity dispersion and dynamical and stellar mass. We find L{sub X} -{sigma} and M{sub stellar}-L{sub X} scaling relations for X-ray and optically selected systems are not dissimilar. The mean fraction of mass found in stars, excluding intracluster light, for our systems is {approx}0.014 with a logarithmic standard deviation of 0.398 dex. We also define and investigate a sample of groups which are X-ray underluminous given the total group stellar mass. For these systems the fraction of stellar mass contributed by the most massive galaxy is typically lower than that found for the total population of

  12. Improvements of the Vis-NIRS Model in the Prediction of Soil Organic Matter Content Using Spectral Pretreatments, Sample Selection, and Wavelength Optimization

    Science.gov (United States)

    Lin, Z. D.; Wang, Y. B.; Wang, R. J.; Wang, L. S.; Lu, C. P.; Zhang, Z. Y.; Song, L. T.; Liu, Y.

    2017-07-01

    A total of 130 topsoil samples collected from Guoyang County, Anhui Province, China, were used to establish a Vis-NIR model for the prediction of organic matter content (OMC) in lime concretion black soils. Different spectral pretreatments were applied for minimizing the irrelevant and useless information of the spectra and increasing the spectra correlation with the measured values. Subsequently, the Kennard-Stone (KS) method and sample set partitioning based on joint x-y distances (SPXY) were used to select the training set. Successive projection algorithm (SPA) and genetic algorithm (GA) were then applied for wavelength optimization. Finally, the principal component regression (PCR) model was constructed, in which the optimal number of principal components was determined using the leave-one-out cross validation technique. The results show that the combination of the Savitzky-Golay (SG) filter for smoothing and multiplicative scatter correction (MSC) can eliminate the effect of noise and baseline drift; the SPXY method is preferable to KS in the sample selection; both the SPA and the GA can significantly reduce the number of wavelength variables and favorably increase the accuracy, especially GA, which greatly improved the prediction accuracy of soil OMC with Rcc, RMSEP, and RPD up to 0.9316, 0.2142, and 2.3195, respectively.

  13. Polymer platforms for selective detection of cocaine in street samples adulterated with levamisole.

    Science.gov (United States)

    Florea, Anca; Cowen, Todd; Piletsky, Sergey; De Wael, Karolien

    2018-08-15

    Accurate drug detection is of utmost importance for fighting against drug abuse. With a high number of cutting agents and adulterants being added to cut or mask drugs in street powders the number of false results is increasing. We demonstrate for the first time the usefulness of employing polymers readily synthesized by electrodeposition to selectively detect cocaine in the presence of the commonly used adulterant levamisole. The polymers were selected by computational modelling to exhibit high binding affinity towards cocaine and deposited directly on the surface of graphene-modified electrodes via electropolymerization. The resulting platforms allowed a distinct electrochemical signal for cocaine, which is otherwise suppressed by levamisole. Square wave voltammetry was used to quantify cocaine alone and in the presence of levamisole. The usefulness of the platforms was demonstrated in the screening of real street samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Out-of-pocket costs, primary care frequent attendance and sample selection: Estimates from a longitudinal cohort design.

    Science.gov (United States)

    Pymont, Carly; McNamee, Paul; Butterworth, Peter

    2018-03-20

    This paper examines the effect of out-of-pocket costs on subsequent frequent attendance in primary care using data from the Personality and Total Health (PATH) Through Life Project, a representative community cohort study from Canberra, Australia. The analysis sample comprised 1197 respondents with two or more GP consultations, and uses survey data linked to administrative health service use (Medicare) data which provides data on the number of consultations and out-of-pocket costs. Respondents identified in the highest decile of GP use in a year were defined as Frequent Attenders (FAs). Logistic regression models that did not account for potential selection effects showed that out-of-pocket costs incurred during respondents' prior two consultations were significantly associated with subsequent FA status. Respondents who incurred higher costs ($15-$35; or >$35) were less likely to become FAs than those who incurred no or low (attenders. Copyright © 2018. Published by Elsevier B.V.

  15. Learning spectrum's selection in OLAM network for analysis cement samples

    International Nuclear Information System (INIS)

    Huang Ning; Wang Peng; Tang Daiquan; Hu Renlan

    2010-01-01

    It uses OLAM artificial neural network to analyze the samples of cement raw material. Two kinds of spectrums are used for network learning: pure-element spectrum and mix-element spectrum. The output of pure-element method can be used to construct a simulate spectrum, which can be compared with the original spectrum and judge the shift of spectrum; the mix-element method can store more message and correct the matrix effect, but the multicollinearity among spectrums can cause some side effect to the results. (authors)

  16. 40 CFR 86.607-84 - Sample selection.

    Science.gov (United States)

    2010-07-01

    ... Auditing of New Light-Duty Vehicles, Light-Duty Trucks, and Heavy-Duty Vehicles § 86.607-84 Sample..., once a manufacturer ships any vehicle from the test sample, it relinquishes the prerogative to conduct...

  17. The effects of dominance, regular inbreeding and sampling design on Q(ST), an estimator of population differentiation for quantitative traits.

    Science.gov (United States)

    Goudet, Jérôme; Büchi, Lucie

    2006-02-01

    To test whether quantitative traits are under directional or homogenizing selection, it is common practice to compare population differentiation estimates at molecular markers (F(ST)) and quantitative traits (Q(ST)). If the trait is neutral and its determinism is additive, then theory predicts that Q(ST) = F(ST), while Q(ST) > F(ST) is predicted under directional selection for different local optima, and Q(ST) sampling designs and find that it is always best to sample many populations (>20) with few families (five) rather than few populations with many families. Provided that estimates of Q(ST) are derived from individuals originating from many populations, we conclude that the pattern Q(ST) > F(ST), and hence the inference of directional selection for different local optima, is robust to the effect of nonadditive gene actions.

  18. Effects of XPS operational parameters on investigated sample surfaces

    International Nuclear Information System (INIS)

    Mrad, O.; Ismail, I.

    2013-04-01

    In this work, we studied the effects of the operating conditions of the xray photoelectron spectroscopy analysis technique (XPS) on the investigated samples. Firstly, the performances of the whole system have been verified as well as the accuracy of the analysis. Afterwards, the problem of the analysis of insulating samples caused by the charge buildup on the surface has been studied. The use of low-energy electron beam (<100 eV) to compensate the surface charge has been applied. The effect of X-ray on the samples have been assessed and was found to be nondestructive within the analysis time. The effect of low- and high-energy electron beams on the sample surface have been investigated. Highenergy electrons were found to have destructive effect on organic samples. The sample heating procedure has been tested and its effect on the chemical stat of the surface was followed. Finally, the ion source was used to determine the elements distribution and the chemical stat of different depths of the sample. A method has been proposed to determine these depths (author).

  19. Analysis of Sunyaev-Zel'dovich effect mass-observable relations using South Pole Telescope observations of an X-ray selected sample of low-mass galaxy clusters and groups

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.; Mohr, J.; Saro, A.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H. M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Foley, R. J.; Gangkofner, D.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Hennig, C.; Hlavacek-Larrondo, J.; Holder, G. P.; Holzapfel, W. L.; Hrubes, J. D.; Jones, C.; Keisler, R.; Lee, A. T.; Leitch, E. M.; Lueker, M.; Luong-Van, D.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L.; Murray, S. S.; Padin, S.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruel, J.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Spieler, H. G.; Stalder, B.; Staniszewski, Z.; Stark, A. A.; Story, K.;  uhada, R.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.

    2015-02-25

    We use microwave observations from the South Pole Telescope (SPT) to examine the Sunyaev–Zel'dovich effect (SZE) signatures of a sample of 46 X-ray selected groups and clusters drawn from ~6 deg2 of the XMM–Newton Blanco Cosmology Survey. These systems extend to redshift z = 1.02 and probe the SZE signal to the lowest X-ray luminosities (≥1042 erg s-1) yet; these sample characteristics make this analysis complementary to previous studies. We develop an analysis tool, using X-ray luminosity as a mass proxy, to extract selection-bias-corrected constraints on the SZE significance and Y_500 mass relations. The former is in good agreement with an extrapolation of the relation obtained from high-mass clusters. However, the latter, at low masses, while in good agreement with the extrapolation from the high-mass SPT clusters, is in tension at 2.8σ with the Planck constraints, indicating the low-mass systems exhibit lower SZE signatures in the SPT data. We also present an analysis of potential sources of contamination. For the radio galaxy point source population, we find 18 of our systems have 843 MHz Sydney University Molonglo Sky Survey sources within 2 arcmin of the X-ray centre, and three of these are also detected at significance >4 by SPT. Of these three, two are associated with the group brightest cluster galaxies, and the third is likely an unassociated quasar candidate. We examine the impact of these point sources on our SZE scaling relation analyses and find no evidence of biases. We also examine the impact of dusty galaxies using constraints from the 220 GHz data. The stacked sample provides 2.8σ significant evidence of dusty galaxy flux, which would correspond to an average underestimate of the SPT Y_500 signal that is (17 ± 9)per cent in this sample of low-mass systems. Finally, we explore the impact of future data from SPTpol and XMM-XXL, showing that it will lead to a factor of 4 to 5 tighter

  20. Pierre Gy's sampling theory and sampling practice heterogeneity, sampling correctness, and statistical process control

    CERN Document Server

    Pitard, Francis F

    1993-01-01

    Pierre Gy's Sampling Theory and Sampling Practice, Second Edition is a concise, step-by-step guide for process variability management and methods. Updated and expanded, this new edition provides a comprehensive study of heterogeneity, covering the basic principles of sampling theory and its various applications. It presents many practical examples to allow readers to select appropriate sampling protocols and assess the validity of sampling protocols from others. The variability of dynamic process streams using variography is discussed to help bridge sampling theory with statistical process control. Many descriptions of good sampling devices, as well as descriptions of poor ones, are featured to educate readers on what to look for when purchasing sampling systems. The book uses its accessible, tutorial style to focus on professional selection and use of methods. The book will be a valuable guide for mineral processing engineers; metallurgists; geologists; miners; chemists; environmental scientists; and practit...

  1. Effects of perceptual load and socially meaningful stimuli on crossmodal selective attention in Autism Spectrum Disorder and neurotypical samples.

    Science.gov (United States)

    Tyndall, Ian; Ragless, Liam; O'Hora, Denis

    2018-04-01

    The present study examined whether increasing visual perceptual load differentially affected both Socially Meaningful and Non-socially Meaningful auditory stimulus awareness in neurotypical (NT, n = 59) adults and Autism Spectrum Disorder (ASD, n = 57) adults. On a target trial, an unexpected critical auditory stimulus (CAS), either a Non-socially Meaningful ('beep' sound) or Socially Meaningful ('hi') stimulus, was played concurrently with the presentation of the visual task. Under conditions of low visual perceptual load both NT and ASD samples reliably noticed the CAS at similar rates (77-81%), whether the CAS was Socially Meaningful or Non-socially Meaningful. However, during high visual perceptual load NT and ASD participants reliably noticed the meaningful CAS (NT = 71%, ASD = 67%), but NT participants were unlikely to notice the Non-meaningful CAS (20%), whereas ASD participants reliably noticed it (80%), suggesting an inability to engage selective attention to ignore non-salient irrelevant distractor stimuli in ASD. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Event dependent sampling of recurrent events

    DEFF Research Database (Denmark)

    Kvist, Tine Kajsa; Andersen, Per Kragh; Angst, Jules

    2010-01-01

    The effect of event-dependent sampling of processes consisting of recurrent events is investigated when analyzing whether the risk of recurrence increases with event count. We study the situation where processes are selected for study if an event occurs in a certain selection interval. Motivation...... retrospective and prospective disease course histories are used. We examine two methods to correct for the selection depending on which data are used in the analysis. In the first case, the conditional distribution of the process given the pre-selection history is determined. In the second case, an inverse...

  3. Representative process sampling - in practice

    DEFF Research Database (Denmark)

    Esbensen, Kim; Friis-Pedersen, Hans Henrik; Julius, Lars Petersen

    2007-01-01

    Didactic data sets representing a range of real-world processes are used to illustrate "how to do" representative process sampling and process characterisation. The selected process data lead to diverse variogram expressions with different systematics (no range vs. important ranges; trends and....../or periodicity; different nugget effects and process variations ranging from less than one lag to full variogram lag). Variogram data analysis leads to a fundamental decomposition into 0-D sampling vs. 1-D process variances, based on the three principal variogram parameters: range, sill and nugget effect...

  4. Progressive sample processing of band selection for hyperspectral imagery

    Science.gov (United States)

    Liu, Keng-Hao; Chien, Hung-Chang; Chen, Shih-Yu

    2017-10-01

    Band selection (BS) is one of the most important topics in hyperspectral image (HSI) processing. The objective of BS is to find a set of representative bands that can represent the whole image with lower inter-band redundancy. Many types of BS algorithms were proposed in the past. However, most of them can be carried on in an off-line manner. It means that they can only be implemented on the pre-collected data. Those off-line based methods are sometime useless for those applications that are timeliness, particular in disaster prevention and target detection. To tackle this issue, a new concept, called progressive sample processing (PSP), was proposed recently. The PSP is an "on-line" framework where the specific type of algorithm can process the currently collected data during the data transmission under band-interleavedby-sample/pixel (BIS/BIP) protocol. This paper proposes an online BS method that integrates a sparse-based BS into PSP framework, called PSP-BS. In PSP-BS, the BS can be carried out by updating BS result recursively pixel by pixel in the same way that a Kalman filter does for updating data information in a recursive fashion. The sparse regression is solved by orthogonal matching pursuit (OMP) algorithm, and the recursive equations of PSP-BS are derived by using matrix decomposition. The experiments conducted on a real hyperspectral image show that the PSP-BS can progressively output the BS status with very low computing time. The convergence of BS results during the transmission can be quickly achieved by using a rearranged pixel transmission sequence. This significant advantage allows BS to be implemented in a real time manner when the HSI data is transmitted pixel by pixel.

  5. Cold Spray Deposition of Freestanding Inconel Samples and Comparative Analysis with Selective Laser Melting

    Science.gov (United States)

    Bagherifard, Sara; Roscioli, Gianluca; Zuccoli, Maria Vittoria; Hadi, Mehdi; D'Elia, Gaetano; Demir, Ali Gökhan; Previtali, Barbara; Kondás, Ján; Guagliano, Mario

    2017-10-01

    Cold spray offers the possibility of obtaining almost zero-porosity buildups with no theoretical limit to the thickness. Moreover, cold spray can eliminate particle melting, evaporation, crystallization, grain growth, unwanted oxidation, undesirable phases and thermally induced tensile residual stresses. Such characteristics can boost its potential to be used as an additive manufacturing technique. Indeed, deposition via cold spray is recently finding its path toward fabrication of freeform components since it can address the common challenges of powder-bed additive manufacturing techniques including major size constraints, deposition rate limitations and high process temperature. Herein, we prepared nickel-based superalloy Inconel 718 samples with cold spray technique and compared them with similar samples fabricated by selective laser melting method. The samples fabricated using both methods were characterized in terms of mechanical strength, microstructural and porosity characteristics, Vickers microhardness and residual stresses distribution. Different heat treatment cycles were applied to the cold-sprayed samples in order to enhance their mechanical characteristics. The obtained data confirm that cold spray technique can be used as a complementary additive manufacturing method for fabrication of high-quality freestanding components where higher deposition rate, larger final size and lower fabrication temperatures are desired.

  6. The Quasar Fraction in Low-Frequency Selected Complete Samples and Implications for Unified Schemes

    Science.gov (United States)

    Willott, Chris J.; Rawlings, Steve; Blundell, Katherine M.; Lacy, Mark

    2000-01-01

    Low-frequency radio surveys are ideal for selecting orientation-independent samples of extragalactic sources because the sample members are selected by virtue of their isotropic steep-spectrum extended emission. We use the new 7C Redshift Survey along with the brighter 3CRR and 6C samples to investigate the fraction of objects with observed broad emission lines - the 'quasar fraction' - as a function of redshift and of radio and narrow emission line luminosity. We find that the quasar fraction is more strongly dependent upon luminosity (both narrow line and radio) than it is on redshift. Above a narrow [OII] emission line luminosity of log(base 10) (L(sub [OII])/W) approximately > 35 [or radio luminosity log(base 10) (L(sub 151)/ W/Hz.sr) approximately > 26.5], the quasar fraction is virtually independent of redshift and luminosity; this is consistent with a simple unified scheme with an obscuring torus with a half-opening angle theta(sub trans) approximately equal 53 deg. For objects with less luminous narrow lines, the quasar fraction is lower. We show that this is not due to the difficulty of detecting lower-luminosity broad emission lines in a less luminous, but otherwise similar, quasar population. We discuss evidence which supports at least two probable physical causes for the drop in quasar fraction at low luminosity: (i) a gradual decrease in theta(sub trans) and/or a gradual increase in the fraction of lightly-reddened (0 approximately quasar luminosity; and (ii) the emergence of a distinct second population of low luminosity radio sources which, like M8T, lack a well-fed quasar nucleus and may well lack a thick obscuring torus.

  7. Autonomous site selection and instrument positioning for sample acquisition

    Science.gov (United States)

    Shaw, A.; Barnes, D.; Pugh, S.

    The European Space Agency Aurora Exploration Program aims to establish a European long-term programme for the exploration of Space, culminating in a human mission to space in the 2030 timeframe. Two flagship missions, namely Mars Sample Return and ExoMars, have been proposed as recognised steps along the way. The Exomars Rover is the first of these flagship missions and includes a rover carrying the Pasteur Payload, a mobile exobiology instrumentation package, and the Beagle 2 arm. The primary objective is the search for evidence of past or present life on mars, but the payload will also study the evolution of the planet and the atmosphere, look for evidence of seismological activity and survey the environment in preparation for future missions. The operation of rovers in unknown environments is complicated, and requires large resources not only on the planet but also in ground based operations. Currently, this can be very labour intensive, and costly, if large teams of scientists and engineers are required to assess mission progress, plan mission scenarios, and construct a sequence of events or goals for uplink. Furthermore, the constraints in communication imposed by the time delay involved over such large distances, and line-of-sight required, make autonomy paramount to mission success, affording the ability to operate in the event of communications outages and be opportunistic with respect to scientific discovery. As part of this drive to reduce mission costs and increase autonomy the Space Robotics group at the University of Wales, Aberystwyth is researching methods of autonomous site selection and instrument positioning, directly applicable to the ExoMars mission. The site selection technique used builds on the geometric reasoning algorithms used previously for localisation and navigation [Shaw 03]. It is proposed that a digital elevation model (DEM) of the local surface, generated during traverse and without interaction from ground based operators, can be

  8. Effect of season on the quality of forages selected by sheep in citrus plantations in Ghana

    Directory of Open Access Journals (Sweden)

    Leonard K. Adjorlolo

    2014-09-01

    Full Text Available The study aimed at assessing the effects of season on chemical composition of forages selected by sheep grazing in a citrus plantation. Forage species growing in a sweet orange (Citrus sinensis plantation were identified and sampled monthly for 2 years. Samples were bulked on monthly basis for chemical analysis. The average dry matter content of the forages increased from the rainy to the dry season but effects of season on the chemical components were inconsistent. Some species, such as Asystasia gangetica, had a higher crude protein concentration in the dry season, whereas for others, such as Panicum repens, the reverse occurred. However, average concentrations of crude protein, detergent fiber and components of fiber for all species for the rainy season were not significantly different from the dry season values. It was concluded that there were differences among forage species in their responses to changing seasons, such that grazing ruminants may select a diet to enable them to meet their nutritional requirements, provided forage biomass is adequate.Keywords: Crop-livestock integration, tree plantations, chemical composition, seasonal effects, forage quality.DOI: 10.17138/TGFT(2271-277

  9. Effective sample labeling

    International Nuclear Information System (INIS)

    Rieger, J.T.; Bryce, R.W.

    1990-01-01

    Ground-water samples collected for hazardous-waste and radiological monitoring have come under strict regulatory and quality assurance requirements as a result of laws such as the Resource Conservation and Recovery Act. To comply with these laws, the labeling system used to identify environmental samples had to be upgraded to ensure proper handling and to protect collection personnel from exposure to sample contaminants and sample preservatives. The sample label now used as the Pacific Northwest Laboratory is a complete sample document. In the event other paperwork on a labeled sample were lost, the necessary information could be found on the label

  10. Preparation and evaluation of a novel molecularly imprinted polymer coating for selective extraction of indomethacin from biological samples by electrochemically controlled in-tube solid phase microextraction

    Energy Technology Data Exchange (ETDEWEB)

    Asiabi, Hamid [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Yamini, Yadollah, E-mail: yyamini@modares.ac.ir [Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Seidi, Shahram; Ghahramanifard, Fazel [Department of Analytical Chemistry, Faculty of Chemistry, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2016-03-24

    -line method for selective extraction and preconcentration of the indomethacin in biological samples was developed. - Highlights: • Molecularly imprinted polymer coated in-tube solid-phase microextraction was prepared. • Electrochemically controlled in-tube solid-phase microextraction-HPLC was developed. • Method was applied for selective extraction of indomethacin from biological samples. • The effective parameters on the extraction efficiency of indomethacin were optimized. • The method showed good linearity for indomethacin in the range of 0.1–200 μg L{sup −1}.

  11. Dissociating action-effect activation and effect-based response selection.

    Science.gov (United States)

    Schwarz, Katharina A; Pfister, Roland; Wirth, Robert; Kunde, Wilfried

    2018-05-25

    Anticipated action effects have been shown to govern action selection and initiation, as described in ideomotor theory, and they have also been demonstrated to determine crosstalk between different tasks in multitasking studies. Such effect-based crosstalk was observed not only in a forward manner (with a first task influencing performance in a following second task) but also in a backward manner (the second task influencing the preceding first task), suggesting that action effect codes can become activated prior to a capacity-limited processing stage often denoted as response selection. The process of effect-based response production, by contrast, has been proposed to be capacity-limited. These observations jointly suggest that effect code activation can occur independently of effect-based response production, though this theoretical implication has not been tested directly at present. We tested this hypothesis by employing a dual-task set-up in which we manipulated the ease of effect-based response production (via response-effect compatibility) in an experimental design that allows for observing forward and backward crosstalk. We observed robust crosstalk effects and response-effect compatibility effects alike, but no interaction between both effects. These results indicate that effect activation can occur in parallel for several tasks, independently of effect-based response production, which is confined to one task at a time. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Effect of Gamma Radiation and Electron Beam on Microbiological Quality and Protein Patterns of 4 Selected Beans

    International Nuclear Information System (INIS)

    Chookaew, S.; Eamsir, J.; Pewlong, W.; Sajjabut, S.

    2014-01-01

    The aim of the present study was to evaluate the effect of gamma ray and electron beam on microbiological quality and protein pattern of four selected beans: mung beans, soy beans, peanuts and black beans. All beans samples were exposed to irradiation at doses of 0, 0.5, 1, and 2 kGy before evaluated for their microbiological quality using AOAC method and protein analysis by gel electrophoresis. Results showed that the amount of bacteria, yeast and mold of irradiated mung beans and peanuts were reduced, whereas these microbiological quality values remained relatively the same for irradiated soy beans and black beans compared to non-irradiated samples. In terms of protein analysis, the protein patterns of the irradiated beans were of the same quality as the non-irradiated samples. To further tested the effect of irradiation on the bean's protein at higher doses, all four selected beans were exposed to gamma ray at 10, 50, 100, 150 and 200 kGy. We found that the protein patterns of mung beans, peanuts and black beans were altered at doses above 50 kGy.

  13. Quantitative analysis of semivolatile organic compounds in selected fractions of air sample extracts by GC/MI-IR spectrometry

    International Nuclear Information System (INIS)

    Childers, J.W.; Wilson, N.K.; Barbour, R.K.

    1990-01-01

    The authors are currently investigating the capabilities of gas chromatography/matrix isolation infrared (GC/MI-IR) spectrometry for the determination of semivolatile organic compounds (SVOCs) in environmental air sample extracts. Their efforts are focused on the determination of SVOCs such as alkylbenzene positional isomers, which are difficult to separate chromatographically and to distinguish by conventional electron-impact ionization GC/mass spectrometry. They have performed a series of systematic experiments to identify sources of error in quantitative GC/MI-IR analyses. These experiments were designed to distinguish between errors due to instrument design or performance and errors that arise from some characteristic inherent to the GC/MI-IR technique, such as matrix effects. They have investigated repeatability as a function of several aspects of GC/MI IR spectrometry, including sample injection, spectral acquisition, cryogenic disk movement, and matrix deposition. The precision, linearity, dynamic range, and detection limits of a commercial GC/MI-IR system for target SVOCs were determined and compared to those obtained with the system's flame ionization detector. The use of deuterated internal standards in the quantitative GC/MI-IR analysis of selected fractions of ambient air sample extracts will be demonstrated. They will also discuss the current limitations of the technique in quantitative analyses and suggest improvements for future consideration

  14. Effects of selective digestive decontamination (SDD) on the gut resistome.

    Science.gov (United States)

    Buelow, Elena; Gonzalez, Teresita Bello; Versluis, Dennis; Oostdijk, Evelien A N; Ogilvie, Lesley A; van Mourik, Maaike S M; Oosterink, Els; van Passel, Mark W J; Smidt, Hauke; D'Andrea, Marco Maria; de Been, Mark; Jones, Brian V; Willems, Rob J L; Bonten, Marc J M; van Schaik, Willem

    2014-08-01

    Selective digestive decontamination (SDD) is an infection prevention measure for critically ill patients in intensive care units (ICUs) that aims to eradicate opportunistic pathogens from the oropharynx and intestines, while sparing the anaerobic flora, by the application of non-absorbable antibiotics. Selection for antibiotic-resistant bacteria is still a major concern for SDD. We therefore studied the impact of SDD on the reservoir of antibiotic resistance genes (i.e. the resistome) by culture-independent approaches. We evaluated the impact of SDD on the gut microbiota and resistome in a single ICU patient during and after an ICU stay by several metagenomic approaches. We also determined by quantitative PCR the relative abundance of two common aminoglycoside resistance genes in longitudinally collected samples from 12 additional ICU patients who received SDD. The patient microbiota was highly dynamic during the hospital stay. The abundance of antibiotic resistance genes more than doubled during SDD use, mainly due to a 6.7-fold increase in aminoglycoside resistance genes, in particular aph(2″)-Ib and an aadE-like gene. We show that aph(2″)-Ib is harboured by anaerobic gut commensals and is associated with mobile genetic elements. In longitudinal samples of 12 ICU patients, the dynamics of these two genes ranged from a ∼10(4) fold increase to a ∼10(-10) fold decrease in relative abundance during SDD. ICU hospitalization and the simultaneous application of SDD has large, but highly individualized, effects on the gut resistome of ICU patients. Selection for transferable antibiotic resistance genes in anaerobic commensal bacteria could impact the risk of transfer of antibiotic resistance genes to opportunistic pathogens. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. The structured ancestral selection graph and the many-demes limit.

    Science.gov (United States)

    Slade, Paul F; Wakeley, John

    2005-02-01

    We show that the unstructured ancestral selection graph applies to part of the history of a sample from a population structured by restricted migration among subpopulations, or demes. The result holds in the limit as the number of demes tends to infinity with proportionately weak selection, and we have also made the assumptions of island-type migration and that demes are equivalent in size. After an instantaneous sample-size adjustment, this structured ancestral selection graph converges to an unstructured ancestral selection graph with a mutation parameter that depends inversely on the migration rate. In contrast, the selection parameter for the population is independent of the migration rate and is identical to the selection parameter in an unstructured population. We show analytically that estimators of the migration rate, based on pairwise sequence differences, derived under the assumption of neutrality should perform equally well in the presence of weak selection. We also modify an algorithm for simulating genealogies conditional on the frequencies of two selected alleles in a sample. This permits efficient simulation of stronger selection than was previously possible. Using this new algorithm, we simulate gene genealogies under the many-demes ancestral selection graph and identify some situations in which migration has a strong effect on the time to the most recent common ancestor of the sample. We find that a similar effect also increases the sensitivity of the genealogy to selection.

  16. "Every Gene Is Everywhere but the Environment Selects": Global Geolocalization of Gene Sharing in Environmental Samples through Network Analysis.

    Science.gov (United States)

    Fondi, Marco; Karkman, Antti; Tamminen, Manu V; Bosi, Emanuele; Virta, Marko; Fani, Renato; Alm, Eric; McInerney, James O

    2016-05-13

    The spatial distribution of microbes on our planet is famously formulated in the Baas Becking hypothesis as "everything is everywhere but the environment selects." While this hypothesis does not strictly rule out patterns caused by geographical effects on ecology and historical founder effects, it does propose that the remarkable dispersal potential of microbes leads to distributions generally shaped by environmental factors rather than geographical distance. By constructing sequence similarity networks from uncultured environmental samples, we show that microbial gene pool distributions are not influenced nearly as much by geography as ecology, thus extending the Bass Becking hypothesis from whole organisms to microbial genes. We find that gene pools are shaped by their broad ecological niche (such as sea water, fresh water, host, and airborne). We find that freshwater habitats act as a gene exchange bridge between otherwise disconnected habitats. Finally, certain antibiotic resistance genes deviate from the general trend of habitat specificity by exhibiting a high degree of cross-habitat mobility. The strong cross-habitat mobility of antibiotic resistance genes is a cause for concern and provides a paradigmatic example of the rate by which genes colonize new habitats when new selective forces emerge. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  17. Selection dramatically reduces effective population size in HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Mittler John E

    2008-05-01

    Full Text Available Abstract Background In HIV-1 evolution, a 100–100,000 fold discrepancy between census size and effective population size (Ne has been noted. Although it is well known that selection can reduce Ne, high in vivo mutation and recombination rates complicate attempts to quantify the effects of selection on HIV-1 effective size. Results We use the inbreeding coefficient and the variance in allele frequency at a linked neutral locus to estimate the reduction in Ne due to selection in the presence of mutation and recombination. With biologically realistic mutation rates, the reduction in Ne due to selection is determined by the strength of selection, i.e., the stronger the selection, the greater the reduction. However, the dependence of Ne on selection can break down if recombination rates are very high (e.g., r ≥ 0.1. With biologically likely recombination rates, our model suggests that recurrent selective sweeps similar to those observed in vivo can reduce within-host HIV-1 effective population sizes by a factor of 300 or more. Conclusion Although other factors, such as unequal viral reproduction rates and limited migration between tissue compartments contribute to reductions in Ne, our model suggests that recurrent selection plays a significant role in reducing HIV-1 effective population sizes in vivo.

  18. 40 CFR 91.506 - Engine sample selection.

    Science.gov (United States)

    2010-07-01

    ... paragraph (b)(2) of this section. It defines one-tail, 95 percent confidence intervals. σ=actual test sample... individual engine x=mean of emission test results of the actual sample FEL=Family Emission Limit n=The actual... carry-over engine families: After one engine is tested, the manufacturer will combine the test with the...

  19. THE EFFECT OF SELECTED PHYSICAL AND CHEMICAL PARAMETERS ON MICROBIOLOGICAL STATUS OF THE VISTULA RIVER NEAR WARSAW

    Directory of Open Access Journals (Sweden)

    Janusz Augustynowicz

    2016-02-01

    Full Text Available The types of organisms present in water reservoirs depend on water purity and biochemical processes that occur. Therefore, one of the methods of water quality assessment is to determine its condition by determining the biological indicators, including microbiological parameters. The aim of the experiment presented in this paper was to investigate the effects of selected physical and chemical parameters of water samples from the Vistula River on the microbiological status of water. The experiment was conducted in water samples collected in the central part of the Vistula River in Warsaw. The analyses of selected parameters were performed once a month throughout the year. Microbiological tests included: number of nitrogen fixing bacteria, MPN nitrifying bacteria, MPN sulfate-reducing bacteria. Physical and chemical parameters such as temperature, pH and total nitrogen content were determined in water samples. The results showed a correlation between temperature, pH and microbiological parameters. However, there was no significant correlation between the number of tested microorganisms and the concentration of total nitrogen in water samples.

  20. Why sample selection matters in exploratory factor analysis: implications for the 12-item World Health Organization Disability Assessment Schedule 2.0.

    Science.gov (United States)

    Gaskin, Cadeyrn J; Lambert, Sylvie D; Bowe, Steven J; Orellana, Liliana

    2017-03-11

    Sample selection can substantially affect the solutions generated using exploratory factor analysis. Validation studies of the 12-item World Health Organization (WHO) Disability Assessment Schedule 2.0 (WHODAS 2.0) have generally involved samples in which substantial proportions of people had no, or minimal, disability. With the WHODAS 2.0 oriented towards measuring disability across six life domains (cognition, mobility, self-care, getting along, life activities, and participation in society), performing factor analysis with samples of people with disability may be more appropriate. We determined the influence of the sampling strategy on (a) the number of factors extracted and (b) the factor structure of the WHODAS 2.0. Using data from adults aged 50+ from the six countries in Wave 1 of the WHO's longitudinal Study on global AGEing and adult health (SAGE), we repeatedly selected samples (n = 750) using two strategies: (1) simple random sampling that reproduced nationally representative distributions of WHODAS 2.0 summary scores for each country (i.e., positively skewed distributions with many zero scores indicating the absence of disability), and (2) stratified random sampling with weights designed to obtain approximately symmetric distributions of summary scores for each country (i.e. predominantly including people with varying degrees of disability). Samples with skewed distributions typically produced one-factor solutions, except for the two countries with the lowest percentages of zero scores, in which the majority of samples produced two factors. Samples with approximately symmetric distributions, generally produced two- or three-factor solutions. In the two-factor solutions, the getting along domain items loaded on one factor (commonly with a cognition domain item), with remaining items loading on a second factor. In the three-factor solutions, the getting along and self-care domain items loaded separately on two factors and three other domains

  1. Strategy for Ranking the Science Value of the Surface of Asteroid 101955 Bennu for Sample Site Selection for Osiris-REx

    Science.gov (United States)

    Nakamura-Messenger, K.; Connolly, H. C., Jr.; Lauretta, D. S.

    2014-01-01

    OSRIS-REx is NASA's New Frontiers 3 sample return mission that will return at least 60 g of pristine surface material from near-Earth asteroid 101955 Bennu in September 2023. The scientific value of the sample increases enormously with the amount of knowledge captured about the geological context from which the sample is collected. The OSIRIS-REx spacecraft is highly maneuverable and capable of investigating the surface of Bennu at scales down to the sub-cm. The OSIRIS-REx instruments will characterize the overall surface geology including spectral properties, microtexture, and geochemistry of the regolith at the sampling site in exquisite detail for up to 505 days after encountering Bennu in August 2018. The mission requires at the very minimum one acceptable location on the asteroid where a touch-and-go (TAG) sample collection maneuver can be successfully per-formed. Sample site selection requires that the follow-ing maps be produced: Safety, Deliverability, Sampleability, and finally Science Value. If areas on the surface are designated as safe, navigation can fly to them, and they have ingestible regolith, then the scientific value of one site over another will guide site selection.

  2. PeptideManager: A Peptide Selection Tool for Targeted Proteomic Studies Involving Mixed Samples from Different Species

    Directory of Open Access Journals (Sweden)

    Kevin eDemeure

    2014-09-01

    Full Text Available The search for clinically useful protein biomarkers using advanced mass spectrometry approaches represents a major focus in cancer research. However, the direct analysis of human samples may be challenging due to limited availability, the absence of appropriate control samples, or the large background variability observed in patient material. As an alternative approach, human tumors orthotopically implanted into a different species (xenografts are clinically relevant models that have proven their utility in pre-clinical research. Patient derived xenografts for glioblastoma have been extensively characterized in our laboratory and have been shown to retain the characteristics of the parental tumor at the phenotypic and genetic level. Such models were also found to adequately mimic the behavior and treatment response of human tumors. The reproducibility of such xenograft models, the possibility to identify their host background and perform tumor-host interaction studies, are major advantages over the direct analysis of human samples.At the proteome level, the analysis of xenograft samples is challenged by the presence of proteins from two different species which, depending on tumor size, type or location, often appear at variable ratios. Any proteomics approach aimed at quantifying proteins within such samples must consider the identification of species specific peptides in order to avoid biases introduced by the host proteome. Here, we present an in-house methodology and tool developed to select peptides used as surrogates for protein candidates from a defined proteome (e.g., human in a host proteome background (e.g., mouse, rat suited for a mass spectrometry analysis. The tools presented here are applicable to any species specific proteome, provided a protein database is available. By linking the information from both proteomes, PeptideManager significantly facilitates and expedites the selection of peptides used as surrogates to analyze

  3. Impact of selective genotyping in the training population on accuracy and bias of genomic selection.

    Science.gov (United States)

    Zhao, Yusheng; Gowda, Manje; Longin, Friedrich H; Würschum, Tobias; Ranc, Nicolas; Reif, Jochen C

    2012-08-01

    Estimating marker effects based on routinely generated phenotypic data of breeding programs is a cost-effective strategy to implement genomic selection. Truncation selection in breeding populations, however, could have a strong impact on the accuracy to predict genomic breeding values. The main objective of our study was to investigate the influence of phenotypic selection on the accuracy and bias of genomic selection. We used experimental data of 788 testcross progenies from an elite maize breeding program. The testcross progenies were evaluated in unreplicated field trials in ten environments and fingerprinted with 857 SNP markers. Random regression best linear unbiased prediction method was used in combination with fivefold cross-validation based on genotypic sampling. We observed a substantial loss in the accuracy to predict genomic breeding values in unidirectional selected populations. In contrast, estimating marker effects based on bidirectional selected populations led to only a marginal decrease in the prediction accuracy of genomic breeding values. We concluded that bidirectional selection is a valuable approach to efficiently implement genomic selection in applied plant breeding programs.

  4. A mechanistic basis for the effect of aluminum content on ethene selectivity in methanol-to-hydrocarbons conversion on HZSM-5

    KAUST Repository

    Khare, Rachit; Liu, Zhaohui; Han, Yu; Bhan, Aditya

    2017-01-01

    Increasing crystallize size or aluminum content in MFI-type zeolites independently enhances the propagation of the aromatics-based methylation/dealkylation cycle relative to that of the olefins-based methylation/cracking cycle in methanol-to-hydrocarbons (MTH) conversion and consequentially results in higher ethene selectivity. Ethene selectivity increases monotonically with increasing aluminum content for HZSM-5 samples with nearly identical crystallite size consequent to an increase in the intracrystalline contact time analogous to our recent report detailing the effects of crystallite size (Khare et al., 2015) on MTH selectivity. The confected effects of crystallite size and site density on MTH selectivity can therefore, be correlated using a descriptor that represents the average number of acid sites that an olefin-precursor will interact with before elution.

  5. A mechanistic basis for the effect of aluminum content on ethene selectivity in methanol-to-hydrocarbons conversion on HZSM-5

    KAUST Repository

    Khare, Rachit

    2017-03-20

    Increasing crystallize size or aluminum content in MFI-type zeolites independently enhances the propagation of the aromatics-based methylation/dealkylation cycle relative to that of the olefins-based methylation/cracking cycle in methanol-to-hydrocarbons (MTH) conversion and consequentially results in higher ethene selectivity. Ethene selectivity increases monotonically with increasing aluminum content for HZSM-5 samples with nearly identical crystallite size consequent to an increase in the intracrystalline contact time analogous to our recent report detailing the effects of crystallite size (Khare et al., 2015) on MTH selectivity. The confected effects of crystallite size and site density on MTH selectivity can therefore, be correlated using a descriptor that represents the average number of acid sites that an olefin-precursor will interact with before elution.

  6. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  7. Sample design effects in landscape genetics

    Science.gov (United States)

    Oyler-McCance, Sara J.; Fedy, Bradley C.; Landguth, Erin L.

    2012-01-01

    An important research gap in landscape genetics is the impact of different field sampling designs on the ability to detect the effects of landscape pattern on gene flow. We evaluated how five different sampling regimes (random, linear, systematic, cluster, and single study site) affected the probability of correctly identifying the generating landscape process of population structure. Sampling regimes were chosen to represent a suite of designs common in field studies. We used genetic data generated from a spatially-explicit, individual-based program and simulated gene flow in a continuous population across a landscape with gradual spatial changes in resistance to movement. Additionally, we evaluated the sampling regimes using realistic and obtainable number of loci (10 and 20), number of alleles per locus (5 and 10), number of individuals sampled (10-300), and generational time after the landscape was introduced (20 and 400). For a simulated continuously distributed species, we found that random, linear, and systematic sampling regimes performed well with high sample sizes (>200), levels of polymorphism (10 alleles per locus), and number of molecular markers (20). The cluster and single study site sampling regimes were not able to correctly identify the generating process under any conditions and thus, are not advisable strategies for scenarios similar to our simulations. Our research emphasizes the importance of sampling data at ecologically appropriate spatial and temporal scales and suggests careful consideration for sampling near landscape components that are likely to most influence the genetic structure of the species. In addition, simulating sampling designs a priori could help guide filed data collection efforts.

  8. Microbiological sampling plan based on risk classification to verify supplier selection and production of served meals in food service operation.

    Science.gov (United States)

    Lahou, Evy; Jacxsens, Liesbeth; Van Landeghem, Filip; Uyttendaele, Mieke

    2014-08-01

    Food service operations are confronted with a diverse range of raw materials and served meals. The implementation of a microbial sampling plan in the framework of verification of suppliers and their own production process (functionality of their prerequisite and HACCP program), demands selection of food products and sampling frequencies. However, these are often selected without a well described scientifically underpinned sampling plan. Therefore, an approach on how to set-up a focused sampling plan, enabled by a microbial risk categorization of food products, for both incoming raw materials and meals served to the consumers is presented. The sampling plan was implemented as a case study during a one-year period in an institutional food service operation to test the feasibility of the chosen approach. This resulted in 123 samples of raw materials and 87 samples of meal servings (focused on high risk categorized food products) which were analyzed for spoilage bacteria, hygiene indicators and food borne pathogens. Although sampling plans are intrinsically limited in assessing the quality and safety of sampled foods, it was shown to be useful to reveal major non-compliances and opportunities to improve the food safety management system in place. Points of attention deduced in the case study were control of Listeria monocytogenes in raw meat spread and raw fish as well as overall microbial quality of served sandwiches and salads. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Sampling a guide for internal auditors

    CERN Document Server

    Apostolou, Barbara

    2004-01-01

    While it is possible to examine 100 percent of an audit customer's data, the time and cost associated with such a study are often prohibitive. To obtain sufficient, reliable, and relevant information with a limited data set, sampling is an efficient and effective tool. It can help you evaluate the customer's assertions, as well as reach audit conclusions and provide reasonable assurance to your organization. This handbook will help you understand sampling. It also serves as a guide for auditors and students preparing for certification. Topics include: An overview of sampling. Statistical and nonstatistical sampling issues. Sampling selection methods and risks. The pros and cons of popular sampling plans.

  10. Thermal properties of selected cheeses samples

    Directory of Open Access Journals (Sweden)

    Monika BOŽIKOVÁ

    2016-02-01

    Full Text Available The thermophysical parameters of selected cheeses (processed cheese and half hard cheese are presented in the article. Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms. Cheese goes during processing through the thermal and mechanical manipulation, so thermal properties are one of the most important. Knowledge about thermal parameters of cheeses could be used in the process of quality evaluation. Based on the presented facts thermal properties of selected cheeses which are produced by Slovak producers were measured. Theoretical part of article contains description of cheese and description of plane source method which was used for thermal parameters detection. Thermophysical parameters as thermal conductivity, thermal diffusivity and volume specific heat were measured during the temperature stabilisation. The results are presented as relations of thermophysical parameters to the temperature in temperature range from 13.5°C to 24°C. Every point of graphic relation was obtained as arithmetic average from measured values for the same temperature. Obtained results were statistically processed. Presented graphical relations were chosen according to the results of statistical evaluation and also according to the coefficients of determination for every relation. The results of thermal parameters are in good agreement with values measured by other authors for similar types of cheeses.

  11. Soil sampling intercomparison exercise by selected laboratories of the ALMERA Network

    International Nuclear Information System (INIS)

    2009-01-01

    The IAEA's Seibersdorf Laboratories in Austria have the programmatic responsibility to provide assistance to Member State laboratories in maintaining and improving the reliability of analytical measurement results, both in radionuclide and trace element determinations. This is accomplished through the provision of reference materials of terrestrial origin, validated analytical procedures, training in the implementation of internal quality control, and through the evaluation of measurement performance by the organization of worldwide and regional interlaboratory comparison exercises. The IAEA is mandated to support global radionuclide measurement systems related to accidental or intentional releases of radioactivity in the environment. To fulfil this obligation and ensure a reliable, worldwide, rapid and consistent response, the IAEA coordinates an international network of analytical laboratories for the measurement of environmental radioactivity (ALMERA). The network was established by the IAEA in 1995 and makes available to Member States a world-wide network of analytical laboratories capable of providing reliable and timely analysis of environmental samples in the event of an accidental or intentional release of radioactivity. A primary requirement for the ALMERA members is participation in the IAEA interlaboratory comparison exercises, which are specifically organized for ALMERA on a regular basis. These exercises are designed to monitor and demonstrate the performance and analytical capabilities of the network members, and to identify gaps and problem areas where further development is needed. In this framework, the IAEA organized a soil sampling intercomparison exercise (IAEA/SIE/01) for selected laboratories of the ALMERA network. The main objective of this exercise was to compare soil sampling procedures used by different participating laboratories. The performance evaluation results of the interlaboratory comparison exercises performed in the framework of

  12. Effects of Mode of Target Task Selection on Learning about Plants in a Mobile Learning Environment: Effortful Manual Selection versus Effortless QR-Code Selection

    Science.gov (United States)

    Gao, Yuan; Liu, Tzu-Chien; Paas, Fred

    2016-01-01

    This study compared the effects of effortless selection of target plants using quick respond (QR) code technology to effortful manual search and selection of target plants on learning about plants in a mobile device supported learning environment. In addition, it was investigated whether the effectiveness of the 2 selection methods was…

  13. Dietary trace element intakes of a selected sample of Canadian elderly women

    International Nuclear Information System (INIS)

    Gibson, R.S.; MacDonald, A.C.; Martinez, O.B.

    1984-01-01

    Energy, and selected trace intakes of a sample of 90 noninstitutionalized Canadian women (mean age 66.2 +/- 6.2 years) living in a University community and consuming self-selected diets were assessed by chemical analysis of one-day duplicate diets and via 1-day dietary records collected by the subjects. Mean gross energy intake (determined via bomb calorimetry was 6.0 +/- 2.4 MJ (1435 +/- 580 kcal) and mean intakes of Cu and Mn (determined via atomic absorption spectrophotometry) were 1.2 +/- 0.6 mg and 3.8 +/- 2.1 mg/day, respectively. Instrumental neutron activation analysis was used for Cr - median = 77.4 μg/day; Se - median = 69.6 μg/day; Zn - mean + SD = 7.7 +/- 3.6 mg/day; Ag - median = 26.9 μg/day; Cs - median = 4.8 μg/day; Rb - median = 1.6 mg/day; Sb - median = 1.8 μg/day; Sc - median = 0.3 μg/day. Dietary intakes of Cr, Mn and Se for the majority of the subjects fell within the US safe and adequate range. In contrast, a high proportion of subjects had apparently low intakes of dietary Cu and Zn in relation to current US dietary recommendations

  14. LOCAL BENCHMARKS FOR THE EVOLUTION OF MAJOR-MERGER GALAXIES-SPITZER OBSERVATIONS OF A K-BAND SELECTED SAMPLE

    International Nuclear Information System (INIS)

    Xu, C. Kevin; Cheng Yiwen; Lu Nanyao; Mazzarella, Joseph M.; Cutri, Roc; Domingue, Donovan; Huang Jiasheng; Gao Yu; Sun, W.-H.; Surace, Jason

    2010-01-01

    We present Spitzer observations for a sample of close major-merger galaxy pairs (KPAIR sample) selected from cross-matches between the Two Micron All Sky Survey and Sloan Digital Sky Survey Data Release 3. The goals are to study the star formation activity in these galaxies and to set a local bench mark for the cosmic evolution of close major mergers. The Spitzer KPAIR sample (27 pairs, 54 galaxies) includes all spectroscopically confirmed spiral-spiral (S+S) and spiral-elliptical (S+E) pairs in a parent sample that is complete for primaries brighter than K = 12.5 mag, projected separations of 5 h -1 kpc ≤ s ≤ 20 h -1 kpc, and mass ratios ≤2.5. The Spitzer data, consisting of images in seven bands (3.6, 4.5, 5.8, 8, 24, 70, 160 μm), show very diversified IR emission properties. Compared to single spiral galaxies in a control sample, only spiral galaxies in S+S pairs show significantly enhanced specific star formation rate (sSFR = SFR/M), whereas spiral galaxies in S+E pairs do not. Furthermore, the SFR enhancement of spiral galaxies in S+S pairs is highly mass-dependent. Only those with M ∼> 10 10.5 M sun show significant enhancement. Relatively low-mass (M ∼ 10 10 M sun ) spirals in S+S pairs have about the same SFR/M compared to their counterparts in the control sample, while those with 10 11 M sun have on average a ∼3 times higher SFR/M than single spirals. There is evidence for a correlation between the global star formation activities (but not the nuclear activities) of the component galaxies in massive S+S major-merger pairs (the H olmberg effect ) . There is no significant difference in the SFR/M between the primaries and the secondaries, nor between spirals of SEP KPAIR =2.54 x 10 -4 (M sun yr -1 Mpc -3 ).

  15. Colorimetric biomimetic sensor systems based on molecularly imprinted polymer membranes for highly-selective detection of phenol in environmental samples

    Directory of Open Access Journals (Sweden)

    Sergeyeva T. A.

    2014-05-01

    Full Text Available Aim. Development of an easy-to-use colorimetric sensor system for fast and accurate detection of phenol in envi- ronmental samples. Methods. Technique of molecular imprinting, method of in situ polymerization of molecularly imprinted polymer membranes. Results. The proposed sensor is based on free-standing molecularly imprinted polymer (MIP membranes, synthesized by in situ polymerization, and having in their structure artificial binding sites capable of selective phenol recognition. The quantitative detection of phenol, selectively adsorbed by the MIP membranes, is based on its reaction with 4-aminoantipyrine, which gives a pink-colored product. The intensity of staining of the MIP membrane is proportional to phenol concentration in the analyzed sample. Phenol can be detected within the range 50 nM–10 mM with limit of detection 50 nM, which corresponds to the concentrations that have to be detected in natural and waste waters in accordance with environmental protection standards. Stability of the MIP-membrane-based sensors was assessed during 12 months storage at room temperature. Conclusions. The sensor system provides highly-selective and sensitive detection of phenol in both mo- del and real (drinking, natural, and waste water samples. As compared to traditional methods of phenol detection, the proposed system is characterized by simplicity of operation and can be used in non-laboratory conditions.

  16. Characteristic of selected frequency luminescence for samples collected in deserts north to Beijing

    International Nuclear Information System (INIS)

    Li Dongxu; Wei Mingjian; Wang Junping; Pan Baolin; Zhao Shiyuan; Liu Zhaowen

    2009-01-01

    Surface sand samples were collected in eight sites of the Horqin and Otindag deserts located in north to Beijing. BG2003 luminescence spectrograph was used to analyze the emitted photons and characteristic spectra of the selected frequency luminescence were obtained. It was found that high intensities of emitted photons stimulated by heat from 85 degree C-135 degree C and 350 degree C-400 degree C. It belong to the traps of 4.13 eV (300 nm), 4.00 eV (310 nm), 3.88 eV (320 nm) and 2.70 eV (460 nm), and the emitted photons belong to traps of 4.00 eV (310 nm), 3.88 eV (320 nm) and 2.70 eV (460 nm) were stimulated by green laser. And sand samples of the eight sites can respond to the increase of definite radiological dose at each wavelength, which is the characteristic spectrum to provide radiation dosimetry basis for dating. There are definite district characteristic in their characteristic spectra. (authors)

  17. Sample-size effects in fast-neutron gamma-ray production measurements: solid-cylinder samples

    International Nuclear Information System (INIS)

    Smith, D.L.

    1975-09-01

    The effects of geometry, absorption and multiple scattering in (n,Xγ) reaction measurements with solid-cylinder samples are investigated. Both analytical and Monte-Carlo methods are employed in the analysis. Geometric effects are shown to be relatively insignificant except in definition of the scattering angles. However, absorption and multiple-scattering effects are quite important; accurate microscopic differential cross sections can be extracted from experimental data only after a careful determination of corrections for these processes. The results of measurements performed using several natural iron samples (covering a wide range of sizes) confirm validity of the correction procedures described herein. It is concluded that these procedures are reliable whenever sufficiently accurate neutron and photon cross section and angular distribution information is available for the analysis. (13 figures, 5 tables) (auth)

  18. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey. I. Sample Selection and Redshift Distribution

    Science.gov (United States)

    Perley, D. A.; Kruhler, T.; Schulze, S.; Postigo, A. De Ugarte; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R.; hide

    2016-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey (SHOALS), a multi-observatory high redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy observational program, consisting of deep Spitzer/IRAC imaging of every field supplemented by similarly deep, multicolor optical/near-IR photometry, plus spectroscopy of events without preexisting redshifts. Our optimized selection cuts combined with host galaxy follow-up have so far enabled redshift measurements for 110 targets (92%) and placed upper limits on all but one of the remainder. About 20% of GRBs in the sample are heavily dust obscured, and at most 2% originate from z > 5.5. Using this sample, we estimate the redshift-dependent GRB rate density, showing it to peak at z approx. 2.5 and fall by at least an order of magnitude toward low (z = 0) redshift, while declining more gradually toward high (z approx. 7) redshift. This behavior is consistent with a progenitor whose formation efficiency varies modestly over cosmic history. Our survey will permit the most detailed examination to date of the connection between the GRB host population and general star-forming galaxies, directly measure evolution in the host population over cosmic time and discern its causes, and provide new constraints on the fraction of cosmic star formation occurring in undetectable galaxies at all redshifts.

  19. Selective control of attention supports the positivity effect in aging.

    Science.gov (United States)

    Sasse, Laura K; Gamer, Matthias; Büchel, Christian; Brassen, Stefanie

    2014-01-01

    There is emerging evidence for a positivity effect in healthy aging, which describes an age-specific increased focus on positive compared to negative information. Life-span researchers have attributed this effect to the selective allocation of cognitive resources in the service of prioritized emotional goals. We explored the basic principles of this assumption by assessing selective attention and memory for visual stimuli, differing in emotional content and self-relevance, in young and old participants. To specifically address the impact of cognitive control, voluntary attentional selection during the presentation of multiple-item displays was analyzed and linked to participants' general ability of cognitive control. Results revealed a positivity effect in older adults' selective attention and memory, which was particularly pronounced for self-relevant stimuli. Focusing on positive and ignoring negative information was most evident in older participants with a generally higher ability to exert top-down control during visual search. Our findings highlight the role of controlled selectivity in the occurrence of a positivity effect in aging. Since the effect has been related to well-being in later life, we suggest that the ability to selectively allocate top-down control might represent a resilience factor for emotional health in aging.

  20. Bias due to sample selection in propensity score matching for a supportive housing program evaluation in New York City.

    Directory of Open Access Journals (Sweden)

    Sungwoo Lim

    Full Text Available OBJECTIVES: Little is known about influences of sample selection on estimation in propensity score matching. The purpose of the study was to assess potential selection bias using one-to-one greedy matching versus optimal full matching as part of an evaluation of supportive housing in New York City (NYC. STUDY DESIGN AND SETTINGS: Data came from administrative data for 2 groups of applicants who were eligible for an NYC supportive housing program in 2007-09, including chronically homeless adults with a substance use disorder and young adults aging out of foster care. We evaluated the 2 matching methods in their ability to balance covariates and represent the original population, and in how those methods affected outcomes related to Medicaid expenditures. RESULTS: In the population with a substance use disorder, only optimal full matching performed well in balancing covariates, whereas both methods created representative populations. In the young adult population, both methods balanced covariates effectively, but only optimal full matching created representative populations. In the young adult population, the impact of the program on Medicaid expenditures was attenuated when one-to-one greedy matching was used, compared with optimal full matching. CONCLUSION: Given covariate balancing with both methods, attenuated program impacts in the young adult population indicated that one-to-one greedy matching introduced selection bias.

  1. EFFECT OF SODIUM PHOSPHATES ON SELECTED FOOD GRADE BACTERIA

    Directory of Open Access Journals (Sweden)

    Stanislav Kráčmar

    2011-04-01

    Full Text Available The aim of this study was to examine the inhibitory effect in vitro of selected sodium phosphates (under the corporate names Hexa 68, Hexa 70, Trikrystal, FST, Pyro 52, KPS, Didi on selected gram-positive and gram-negative bacteria. Seven different concentrations of each phosphate were used. Sensitivity of the bacterial strains to phosphates was observed in broth supplemented with salts. In vitro was showed a negative effect of various phosphates on growth of selected gram-positive bacteria. Orthophosphates and diphosphates (pyrophosphates did not have significant inhibitory effect on tested bacteria at neutral pH. With the exception of phosphate Trikrystal has not been found in vitro significant inhibitory effects on gram-negative bacteria.doi:10.5219/141

  2. A simple and selective method for determination of phthalate biomarkers in vegetable samples by high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Xi; Cui, Kunyan; Zeng, Feng; Li, Shoucong; Zeng, Zunxiang

    2016-06-01

    In the present study, solid-phase extraction cartridges including silica reversed-phase Isolute C18, polymeric reversed-phase Oasis HLB and mixed-mode anion-exchange Oasis MAX, and liquid-liquid extractions with ethyl acetate, n-hexane, dichloromethane and its mixtures were compared for clean-up of phthalate monoesters from vegetable samples. Best recoveries and minimised matrix effects were achieved using ethyl acetate/n-hexane liquid-liquid extraction for these target compounds. A simple and selective method, based on sample preparation by ultrasonic extraction and liquid-liquid extraction clean-up, for the determination of phthalate monoesters in vegetable samples by liquid chromatography/electrospray ionisation-tandem mass spectrometry was developed. The method detection limits for phthalate monoesters ranged from 0.013 to 0.120 ng g(-1). Good linearity (r(2)>0.991) between MQLs and 1000× MQLs was achieved. The intra- and inter-day relative standard deviation values were less than 11.8%. The method was successfully used to determine phthalate monoester metabolites in the vegetable samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The Role of Selection Effects in the Contact Hypothesis: Results from a U.S. National Survey on Sexual Prejudice.

    Science.gov (United States)

    Loehr, Annalise; Doan, Long; Miller, Lisa R

    2015-11-01

    Empirical research has documented that contact with lesbians and gays is associated with more positive feelings toward and greater support for legal rights for them, but we know less about whether these effects extend to informal aspects of same-sex relationships, such as reactions to public displays of affection. Furthermore, many studies have assumed that contact influences levels of sexual prejudice; however, the possibility of selection effects, in which less sexually prejudiced people have contact, and more sexually prejudiced people do not, raises some doubts about this assumption. We used original data from a nationally representative sample of heterosexuals to determine whether those reporting contact with a lesbian, gay, bisexual, or transgender friend or relative exhibited less sexual prejudice toward lesbian and gay couples than those without contact. This study examined the effect of contact on attitudes toward formal rights and a relatively unexplored dimension, informal privileges. We estimated the effect of having contact using traditional (ordinary least squares regression) methods before accounting for selection effects using propensity score matching. After accounting for selection effects, we found no significant differences between the attitudes of those who had contact and those who did not, for either formal or informal measures. Thus, selection effects appeared to play a pivotal role in confounding the link between contact and sexual prejudice, and future studies should exercise caution in interpreting results that do not account for such selection effects.

  4. AID SELECTIVITY PRACTICE AND AID EFFECTIVENESS IN SUB-SAHARAN AFRICA

    Directory of Open Access Journals (Sweden)

    Adeniyi Jimmy Adedokun

    2017-09-01

    Full Text Available Foreign aid strategies have undergone restructuring as donors adopt aid selectivity practice to improve aid effectiveness. This study investigates the impact of aid selectivity practice on aid effectiveness (aid-growth relationship in Sub-Saharan Africa (SSA and several groups of countries within SSA from 1980 to 2012. Employing system generalized methods of moments (system GMM technique; the study produces strong evidence that there is significant improvement in aid effectiveness due to aid selectivity practice.

  5. The NuSTAR  Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

    Science.gov (United States)

    Zappacosta, L.; Comastri, A.; Civano, F.; Puccetti, S.; Fiore, F.; Aird, J.; Del Moro, A.; Lansbury, G. B.; Lanzuisi, G.; Goulding, A.; Mullaney, J. R.; Stern, D.; Ajello, M.; Alexander, D. M.; Ballantyne, D. R.; Bauer, F. E.; Brandt, W. N.; Chen, C.-T. J.; Farrah, D.; Harrison, F. A.; Gandhi, P.; Lanz, L.; Masini, A.; Marchesi, S.; Ricci, C.; Treister, E.

    2018-02-01

    We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting flux of S(8{--}24 {keV})=7× {10}-14 {erg} {{{s}}}-1 {{cm}}-2 in the multi-tiered NuSTAR extragalactic survey program. The sources span a redshift range z=0{--}2.1 (median =0.58). The spectral analysis is performed over the broad 0.5–24 keV energy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical and physically motivated models. This constitutes the largest sample of AGN selected at > 10 {keV} to be homogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters such as photon index, column density ({N}{{H}}), reflection parameter ({\\boldsymbol{R}}), and 10–40 keV luminosity ({L}{{X}}). Heavily obscured ({log}[{N}{{H}}/{{cm}}-2]≥slant 23) and Compton-thick (CT; {log}[{N}{{H}}/{{cm}}-2]≥slant 24) AGN constitute ∼25% (15–17 sources) and ∼2–3% (1–2 sources) of the sample, respectively. The observed {N}{{H}} distribution agrees fairly well with predictions of cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGN as a function of {N}{{H}}, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CT AGN relative to {log}[{N}{{H}}/{{cm}}-2]=20{--}24 AGN is poorly constrained, formally in the range 2–56% (90% upper limit of 66%). We derived a fraction (f abs) of obscured AGN ({log}[{N}{{H}}/{{cm}}-2]=22{--}24) as a function of {L}{{X}} in agreement with CXBPSM and previous zvalues.

  6. Modeling the effect of selection history on pop-out visual search.

    Directory of Open Access Journals (Sweden)

    Yuan-Chi Tseng

    Full Text Available While attentional effects in visual selection tasks have traditionally been assigned "top-down" or "bottom-up" origins, more recently it has been proposed that there are three major factors affecting visual selection: (1 physical salience, (2 current goals and (3 selection history. Here, we look further into selection history by investigating Priming of Pop-out (POP and the Distractor Preview Effect (DPE, two inter-trial effects that demonstrate the influence of recent history on visual search performance. Using the Ratcliff diffusion model, we model observed saccadic selections from an oddball search experiment that included a mix of both POP and DPE conditions. We find that the Ratcliff diffusion model can effectively model the manner in which selection history affects current attentional control in visual inter-trial effects. The model evidence shows that bias regarding the current trial's most likely target color is the most critical parameter underlying the effect of selection history. Our results are consistent with the view that the 3-item color-oddball task used for POP and DPE experiments is best understood as an attentional decision making task.

  7. Beta-thalassemia- institution based analysis of ethnic and geographic distribution, effect of consanguinity and safety of chorionic villus sampling as a diagnostic, tool for pre-natal diagnosis in selected patients

    International Nuclear Information System (INIS)

    Abdullah, K.N.; Liaqat, J.; Azim, W.

    2011-01-01

    To study the ethnic and geographic distribution of Beta-thalassemia amongst the patients included and to study the effect of consanguinity in promoting this disease. Also, to establish the safety of CVS when used as a pre-natal diagnostic tool in aiding the early diagnosis of Beta-thalassemia in selected patients. Study Design: Descriptive Study. Place and Duration of Study: PNS Shifa Karachi, from Jan 2008 to Dec 2008. Patients and Methods: A total of 223 women out of 240 that were referred from all over Sindh to PNS Shifa Hospital Karachi for susceptible gene mutations participated in the study. The standard procedure that was used in this study was trans-abdominal aspiration of chorionic villi through suction needle. The samples were then sent for further analysis to the Pathology Department at PNS Shifa Hospital Karachi. Results: In our study population Beta-thalassemia was most prevalent in Sindhi 107 (48%) followed by Punjabi 46 (21%), 27 (12%) Pathan, and 43 (19%) Balochi. Out of 223 women, 95 were of thalassemia trait, while 85 were of thalassemia major. Fifty five percent of thalassemia trait and 56% of thalassemia major fetus parents were first cousins. The rate of pregnancy loss after performing CVS was 2.0% with no complications reported. Conclusion: It is concluded that highest percentage of thalassemia is in first cousins and sindhi origin families are mostly affected. However CVS is a safe and effective tool for prenatal diagnosis and subsequent counselling in selected couples. (author)

  8. Systematic sampling of discrete and continuous populations: sample selection and the choice of estimator

    Science.gov (United States)

    Harry T. Valentine; David L. R. Affleck; Timothy G. Gregoire

    2009-01-01

    Systematic sampling is easy, efficient, and widely used, though it is not generally recognized that a systematic sample may be drawn from the population of interest with or without restrictions on randomization. The restrictions or the lack of them determine which estimators are unbiased, when using the sampling design as the basis for inference. We describe the...

  9. Surface reconstruction through poisson disk sampling.

    Directory of Open Access Journals (Sweden)

    Wenguang Hou

    Full Text Available This paper intends to generate the approximate Voronoi diagram in the geodesic metric for some unbiased samples selected from original points. The mesh model of seeds is then constructed on basis of the Voronoi diagram. Rather than constructing the Voronoi diagram for all original points, the proposed strategy is to run around the obstacle that the geodesic distances among neighboring points are sensitive to nearest neighbor definition. It is obvious that the reconstructed model is the level of detail of original points. Hence, our main motivation is to deal with the redundant scattered points. In implementation, Poisson disk sampling is taken to select seeds and helps to produce the Voronoi diagram. Adaptive reconstructions can be achieved by slightly changing the uniform strategy in selecting seeds. Behaviors of this method are investigated and accuracy evaluations are done. Experimental results show the proposed method is reliable and effective.

  10. Can selection explain the protective effects of farming on asthma?

    Directory of Open Access Journals (Sweden)

    Wijnand Eduard

    2015-09-01

    No healthy worker selection into farming was observed and changes in asthma prevalence due to early retirement were small. Selection effects are therefore unlikely to explain the protective effects of farming on asthma.

  11. Selective control of attention supports the positivity effect in aging.

    Directory of Open Access Journals (Sweden)

    Laura K Sasse

    Full Text Available There is emerging evidence for a positivity effect in healthy aging, which describes an age-specific increased focus on positive compared to negative information. Life-span researchers have attributed this effect to the selective allocation of cognitive resources in the service of prioritized emotional goals. We explored the basic principles of this assumption by assessing selective attention and memory for visual stimuli, differing in emotional content and self-relevance, in young and old participants. To specifically address the impact of cognitive control, voluntary attentional selection during the presentation of multiple-item displays was analyzed and linked to participants' general ability of cognitive control. Results revealed a positivity effect in older adults' selective attention and memory, which was particularly pronounced for self-relevant stimuli. Focusing on positive and ignoring negative information was most evident in older participants with a generally higher ability to exert top-down control during visual search. Our findings highlight the role of controlled selectivity in the occurrence of a positivity effect in aging. Since the effect has been related to well-being in later life, we suggest that the ability to selectively allocate top-down control might represent a resilience factor for emotional health in aging.

  12. Statistical sampling strategies

    International Nuclear Information System (INIS)

    Andres, T.H.

    1987-01-01

    Systems assessment codes use mathematical models to simulate natural and engineered systems. Probabilistic systems assessment codes carry out multiple simulations to reveal the uncertainty in values of output variables due to uncertainty in the values of the model parameters. In this paper, methods are described for sampling sets of parameter values to be used in a probabilistic systems assessment code. Three Monte Carlo parameter selection methods are discussed: simple random sampling, Latin hypercube sampling, and sampling using two-level orthogonal arrays. Three post-selection transformations are also described: truncation, importance transformation, and discretization. Advantages and disadvantages of each method are summarized

  13. Novel ion-imprinted polymer coated on nanoporous silica as a highly selective sorbent for the extraction of ultratrace quantities of gold ions from mine stone samples

    International Nuclear Information System (INIS)

    Ebrahimzadeh, H.; Moazzen, E.; Amini, M.; Sadeghi, O.

    2013-01-01

    We have developed a gold ion-imprinted polymer (GIP) by incorporating a dipyridyl ligand into an ethylene glycol dimethacrylate matrix which then was coated onto porous silica particles. The material was used for the selective extraction of ultratrace quantities of gold ion from mine stones, this followed by its quantitation by FAAS. The effects of concentration and volume of eluent, pH of the solution, flow rates of sample and eluent, and effect of potentially interfering ions, especially palladium and platinum, was investigated. The limit of detection is -1 , the precision (RSD%) is 1.03 %, and recoveries are >99 %. In order to show the high selectivity and efficiency of the new sorbent, the results were compared to those obtained with more simple sorbents possessing the same functional groups. The accuracy of the method was demonstrated by the accurate determination of gold ions in a certified reference material. To the best of our knowledge, there is no report so far on an imprint for gold ions that has such a selectivity over Pd(II) and Pt(II) ions. (author)

  14. The effect of mis-specification on mean and selection between the Weibull and lognormal models

    Science.gov (United States)

    Jia, Xiang; Nadarajah, Saralees; Guo, Bo

    2018-02-01

    The lognormal and Weibull models are commonly used to analyse data. Although selection procedures have been extensively studied, it is possible that the lognormal model could be selected when the true model is Weibull or vice versa. As the mean is important in applications, we focus on the effect of mis-specification on mean. The effect on lognormal mean is first considered if the lognormal sample is wrongly fitted by a Weibull model. The maximum likelihood estimate (MLE) and quasi-MLE (QMLE) of lognormal mean are obtained based on lognormal and Weibull models. Then, the impact is evaluated by computing ratio of biases and ratio of mean squared errors (MSEs) between MLE and QMLE. For completeness, the theoretical results are demonstrated by simulation studies. Next, the effect of the reverse mis-specification on Weibull mean is discussed. It is found that the ratio of biases and the ratio of MSEs are independent of the location and scale parameters of the lognormal and Weibull models. The influence could be ignored if some special conditions hold. Finally, a model selection method is proposed by comparing ratios concerning biases and MSEs. We also present a published data to illustrate the study in this paper.

  15. Effect of tetracycline dose and treatment-mode on selection of resistant coliform bacteria in nursery pigs

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders

    2017-01-01

    This study describes results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on selection of antibiotic resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4-7 weeks of age) were treated...... with oxytetracycline against Lawsonia intracellularis induced diarrhea in five pig herds. Each group was randomly allocated to one of five treatment groups: oral flock treatment with (i) high (20 mg/kg), (ii) medium (10 mg/kg) and (iii) low (5 mg/kg) dosage, (iv) oral-pen-wise (small group) treatment (10 mg...... significant changes in number or proportion of tetracycline resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin- and sulfonamide-resistant, but not to cefotaxime-resistant strains. In conclusion, difference in dose of oxytetracycline...

  16. Effects of Transport and Storage Conditions on Gene Expression in Blood Samples.

    Science.gov (United States)

    Malentacchi, Francesca; Pizzamiglio, Sara; Wyrich, Ralf; Verderio, Paolo; Ciniselli, Chiara; Pazzagli, Mario; Gelmini, Stefania

    2016-04-01

    Inappropriate handling of blood samples might induce or repress gene expression and/or lead to RNA degradation affecting downstream analysis. In particular, sample transport is a critical step for biobanking or multicenter studies because of uncontrolled variables (i.e., unstable temperature). We report the results of a pilot study implemented within the EC funded SPIDIA project, aimed to investigate the role of transport and storage of blood samples containing and not containing an RNA stabilizer. Blood was collected from a single donor both in EDTA and in PAXgene Blood RNA tubes. Half of the samples were sent to a second laboratory both at room temperature and at 4°C, whereas the remaining samples were stored at room temperature and at 4°C. Gene expression of selected genes (c-FOS, IL-1β, IL-8, and GAPDH) known to be induced or repressed by ex vivo blood handling and of blood-mRNA quality biomarkers identified and validated within the SPIDIA project, which allow for monitoring changes in unstabilized blood samples after collection and during transport and storage, were analyzed by RT-qPCR. If the shipment of blood in tubes not containing RNA stabilizer is not performed under a stable condition, gene profile studies can be affected by the effects of transport. Moreover, also controlled temperature shipment (4°C) can influence the expression of specific genes if blood is collected in tubes not containing a stabilizer. The use of dedicated biomarkers or time course experiments should be performed in order to verify potential bias on gene expression analysis due to sample shipment and storage conditions. Alternatively, the use of RNA stabilizer containing tubes can represent a reliable option to avoid ex vivo RNA changes.

  17. SDSS-IV MaNGA: faint quenched galaxies - I. Sample selection and evidence for environmental quenching

    Science.gov (United States)

    Penny, Samantha J.; Masters, Karen L.; Weijmans, Anne-Marie; Westfall, Kyle B.; Bershady, Matthew A.; Bundy, Kevin; Drory, Niv; Falcón-Barroso, Jesús; Law, David; Nichol, Robert C.; Thomas, Daniel; Bizyaev, Dmitry; Brownstein, Joel R.; Freischlad, Gordon; Gaulme, Patrick; Grabowski, Katie; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Roman-Lopes, Alexandre; Pan, Kaike; Simmons, Audrey; Wake, David A.

    2016-11-01

    Using kinematic maps from the Sloan Digital Sky Survey (SDSS) Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we reveal that the majority of low-mass quenched galaxies exhibit coherent rotation in their stellar kinematics. Our sample includes all 39 quenched low-mass galaxies observed in the first year of MaNGA. The galaxies are selected with Mr > -19.1, stellar masses 109 M⊙ 1.9. They lie on the size-magnitude and σ-luminosity relations for previously studied dwarf galaxies. Just six (15 ± 5.7 per cent) are found to have rotation speeds ve, rot 5 × 1010 M⊙), supporting the hypothesis that galaxy-galaxy or galaxy-group interactions quench star formation in low-mass galaxies. The local bright galaxy density for our sample is ρproj = 8.2 ± 2.0 Mpc-2, compared to ρproj = 2.1 ± 0.4 Mpc-2 for a star-forming comparison sample, confirming that the quenched low-mass galaxies are preferentially found in higher density environments.

  18. A large sample of Kohonen selected E+A (post-starburst) galaxies from the Sloan Digital Sky Survey

    Science.gov (United States)

    Meusinger, H.; Brünecke, J.; Schalldach, P.; in der Au, A.

    2017-01-01

    Context. The galaxy population in the contemporary Universe is characterised by a clear bimodality, blue galaxies with significant ongoing star formation and red galaxies with only a little. The migration between the blue and the red cloud of galaxies is an issue of active research. Post starburst (PSB) galaxies are thought to be observed in the short-lived transition phase. Aims: We aim to create a large sample of local PSB galaxies from the Sloan Digital Sky Survey (SDSS) to study their characteristic properties, particularly morphological features indicative of gravitational distortions and indications for active galactic nuclei (AGNs). Another aim is to present a tool set for an efficient search in a large database of SDSS spectra based on Kohonen self-organising maps (SOMs). Methods: We computed a huge Kohonen SOM for ∼106 spectra from SDSS data release 7. The SOM is made fully available, in combination with an interactive user interface, for the astronomical community. We selected a large sample of PSB galaxies taking advantage of the clustering behaviour of the SOM. The morphologies of both PSB galaxies and randomly selected galaxies from a comparison sample in SDSS Stripe 82 (S82) were inspected on deep co-added SDSS images to search for indications of gravitational distortions. We used the Portsmouth galaxy property computations to study the evolutionary stage of the PSB galaxies and archival multi-wavelength data to search for hidden AGNs. Results: We compiled a catalogue of 2665 PSB galaxies with redshifts z 3 Å and z cloud, in agreement with the idea that PSB galaxies represent the transitioning phase between actively and passively evolving galaxies. The relative frequency of distorted PSB galaxies is at least 57% for EW(Hδ) > 5 Å, significantly higher than in the comparison sample. The search for AGNs based on conventional selection criteria in the radio and MIR results in a low AGN fraction of ∼2-3%. We confirm an MIR excess in the mean SED of

  19. Enhancement of the spectral selectivity of complex samples by measuring them in a frozen state at low temperatures in order to improve accuracy for quantitative analysis. Part II. Determination of viscosity for lube base oils using Raman spectroscopy.

    Science.gov (United States)

    Kim, Mooeung; Chung, Hoeil

    2013-03-07

    The use of selectivity-enhanced Raman spectra of lube base oil (LBO) samples achieved by the spectral collection under frozen conditions at low temperatures was effective for improving accuracy for the determination of the kinematic viscosity at 40 °C (KV@40). A collection of Raman spectra from samples cooled around -160 °C provided the most accurate measurement of KV@40. Components of the LBO samples were mainly long-chain hydrocarbons with molecular structures that were deformable when these were frozen, and the different structural deformabilities of the components enhanced spectral selectivity among the samples. To study the structural variation of components according to the change of sample temperature from cryogenic to ambient condition, n-heptadecane and pristane (2,6,10,14-tetramethylpentadecane) were selected as representative components of LBO samples, and their temperature-induced spectral features as well as the corresponding spectral loadings were investigated. A two-dimensional (2D) correlation analysis was also employed to explain the origin for the improved accuracy. The asynchronous 2D correlation pattern was simplest at the optimal temperature, indicating the occurrence of distinct and selective spectral variations, which enabled the variation of KV@40 of LBO samples to be more accurately assessed.

  20. Eleven-Year Retrospective Report of Super-Selective Venous Sampling for the Evaluation of Recurrent or Persistent Hyperparathyroidism in 32 Patients.

    Science.gov (United States)

    Habibollahi, Peiman; Shin, Benjamin; Shamchi, Sara P; Wachtel, Heather; Fraker, Douglas L; Trerotola, Scott O

    2018-01-01

    Parathyroid venous sampling (PAVS) is usually reserved for patients with persistent or recurrent hyperparathyroidism after parathyroidectomy with inconclusive noninvasive imaging studies. A retrospective study was performed to evaluate the diagnostic efficacy of super-selective PAVS (SSVS) in patients needing revision neck surgery with inconclusive imaging. Patients undergoing PAVS between 2005 and 2016 due to persistent or recurrent hyperparathyroidism following surgery were reviewed. PAVS was performed in all patients using super-selective technique. Single-value measurements within central neck veins performed as part of super-selective PAVS were used to simulate selective venous sampling (SVS) and allow for comparison to data, which might be obtained in a non-super-selective approach. 32 patients (mean age 51 ± 15 years; 8 men and 24 women) met inclusion and exclusion criteria. The sensitivity and positive predictive value (PPV) of SSVS for localizing the source of elevated PTH to a limited area in the neck or chest was 96 and 84%, respectively. Simulated SVS, on the other hand, had a sensitivity of 28% and a PPV of 89% based on the predefined gold standard. SSVS had a significantly higher sensitivity compared to simulated SVS (p localizing the source of hyperparathyroidism in patients undergoing revision surgery for hyperparathyroidism in whom noninvasive imaging studies are inconclusive. SSVS data had also markedly higher sensitivity for localizing disease in these patients compared to simulated SVS.

  1. Relative age effect and selection of young basketball players

    Directory of Open Access Journals (Sweden)

    Vučković Igor

    2013-01-01

    Full Text Available Purpose of the present study was to examine whether influence of relative age effect (RAE exists or not in the selected 13 year old basketball players. Subjects were 20 basketball players (HT=177.35cm±6.73, BW=61.42kg±8.98, average age 13 years and 7 months ±.28, average experience in basketball training 4 years and 6 months ±1.15. Sample was divided in two groups: 11 players born in first half of the year and 9 players born in the second half of the year. One-way ANOVA was used in order to analyze the differences between the two groups of players in set of anthropometric variables (body height, arm span, standing reach height, body weight and percentage of body fat, motor variables (velocity of neuromuscular reaction time, vertical jump, 5 meters sprint, 10 meters sprint, 20 meters sprint, T-test, Zig-zag test, ball throw from sitting position, Sit-ups for 30 seconds and standing forward bend and one functional variable (20-M shuttle run test. Subjects do not differ in applied set of parameters, except in on variable (sit-ups for 30 seconds, p=.040. It was concluded that RAE does not exist in this sample of examinees.

  2. Improved sample treatment for the determination of insoluble soap in sewage sludge samples by liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Cantarero, Samuel; Zafra-Gómez, A; Ballesteros, O; Navalón, A; Vílchez, J L; Crovetto, G; Verge, C; de Ferrer, J A

    2010-09-15

    A new selective and sensitive method for the determination of insoluble fatty acid salts (soap) in sewage sludge samples is proposed. The method involves a clean up of sample with petroleum ether, the conversion of calcium and magnesium insoluble salts into soluble potassium salts, potassium salts extraction with methanol, and a derivatization procedure previous to the liquid chromatography with fluorescence detection (LC-FLD) analysis. Three different extraction techniques (Soxhlet, microwave-assisted extraction and ultrasounds) were compared and microwave-assisted extraction (MAE) was selected as appropriate for our purpose. This allowed to reduce the extraction time and solvent waste (50 mL of methanol in contrast with 250 mL for Soxhlet procedure). The absence of matrix effect was demonstrated with two standards (C(13:0) and C(17:0)) that are not commercials and neither of them has been detected in sewage sludge samples. Therefore, it was possible to evaluate the matrix effect since both standards have similar environmental behaviour (adsorption and precipitation) to commercial soaps (C(10:0)-C(18:0)). The method was successfully applied to samples from different sources and consequently, with different composition. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  3. Neuronal effects of nicotine during auditory selective attention.

    Science.gov (United States)

    Smucny, Jason; Olincy, Ann; Eichman, Lindsay S; Tregellas, Jason R

    2015-06-01

    Although the attention-enhancing effects of nicotine have been behaviorally and neurophysiologically well-documented, its localized functional effects during selective attention are poorly understood. In this study, we examined the neuronal effects of nicotine during auditory selective attention in healthy human nonsmokers. We hypothesized to observe significant effects of nicotine in attention-associated brain areas, driven by nicotine-induced increases in activity as a function of increasing task demands. A single-blind, prospective, randomized crossover design was used to examine neuronal response associated with a go/no-go task after 7 mg nicotine or placebo patch administration in 20 individuals who underwent functional magnetic resonance imaging at 3T. The task design included two levels of difficulty (ordered vs. random stimuli) and two levels of auditory distraction (silence vs. noise). Significant treatment × difficulty × distraction interaction effects on neuronal response were observed in the hippocampus, ventral parietal cortex, and anterior cingulate. In contrast to our hypothesis, U and inverted U-shaped dependencies were observed between the effects of nicotine on response and task demands, depending on the brain area. These results suggest that nicotine may differentially affect neuronal response depending on task conditions. These results have important theoretical implications for understanding how cholinergic tone may influence the neurobiology of selective attention.

  4. [Silvicultural treatments and their selection effects].

    Science.gov (United States)

    Vincent, G

    1973-01-01

    Selection can be defined in terms of its observable consequences as the non random differential reproduction of genotypes (Lerner 1958). In the forest stands we are selecting during the improvements-fellings and reproduction treatments the individuals surpassing in growth or in production of first-class timber. However the silvicultural treatments taken in forest stands guarantee a permanent increase of forest production only in such cases, if they have been taken with respect to the principles of directional (dynamic) selection. These principles require that the trees determined for further growing and for forest regeneration are selected by their hereditary properties, i.e. by their genotypes.For making this selection feasible, our study deals with the genetic parameters and gives some examples of the application of the response, the selection differential, the heritability in the narrow and in the broad sense, as well as of the genetic and genotypic gain. On the strength of this parameter we have the possibility to estimate the economic success of several silvicultural treatments in forest stands.The mentioned examples demonstrate that the selection measures of a higher intensity will be manifested in a higher selection differential, in a higher genetic and genotypic gain and that the mentioned measures show more distinct effects in the variable populations - in natural forest - than in the population characteristic by a smaller variability, e.g. in many uniform artificially established stands.The examples of influences of different selection on the genotypes composition of population prove that genetics instructs us to differentiate the different genotypes of the same species and gives us at the same time a new criterions for evaluating selectional treatments. These criterions from economic point of view is necessary to consider in silviculture as advantageous even for the reason that we can judge from these criterions the genetical composition of forest stands

  5. The effect of size-selective samplers (cyclones) on XRD response

    CSIR Research Space (South Africa)

    Pretorius, CJ

    2011-07-01

    Full Text Available The study evaluated five size-selective samplers used in the South African mining industry to determine how their performance affects the X-ray powder diffraction (XRD) response when respirable dust samples are analysed for quartz using direct...

  6. Mediators of Effects of a Selective Family-Focused Violence Prevention Approach for Middle School Students

    Science.gov (United States)

    2013-01-01

    This study examined how parenting and family characteristics targeted in a selective prevention program mediated effects on key youth proximal outcomes related to violence perpetration. The selective intervention was evaluated within the context of a multi-site trial involving random assignment of 37 schools to four conditions: a universal intervention composed of a student social-cognitive curriculum and teacher training, a selective family-focused intervention with a subset of high-risk students, a condition combining these two interventions, and a no-intervention control condition. Two cohorts of sixth-grade students (total N=1,062) exhibiting high levels of aggression and social influence were the sample for this study. Analyses of pre-post change compared to controls using intent-to-treat analyses found no significant effects. However, estimates incorporating participation of those assigned to the intervention and predicted participation among those not assigned revealed significant positive effects on student aggression, use of aggressive strategies for conflict management, and parental estimation of student’s valuing of achievement. Findings also indicated intervention effects on two targeted family processes: discipline practices and family cohesion. Mediation analyses found evidence that change in these processes mediated effects on some outcomes, notably aggressive behavior and valuing of school achievement. Results support the notion that changing parenting practices and the quality of family relationships can prevent the escalation in aggression and maintain positive school engagement for high-risk youth. PMID:21932067

  7. 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.

  8. Structure and Mechanical Properties of the AlSi10Mg Alloy Samples Manufactured by Selective Laser Melting

    Science.gov (United States)

    Li, Xiaodan; Ni, Jiaqiang; Zhu, Qingfeng; Su, Hang; Cui, Jianzhong; Zhang, Yifei; Li, Jianzhong

    2017-11-01

    The AlSi10Mg alloy samples with the size of 14×14×91mm were produced by the selective laser melting (SLM) method in different building direction. The structures and the properties at -70°C of the sample in different direction were investigated. The results show that the structure in different building direction shows different morphology. The fish scale structures distribute on the side along the building direction, and the oval structures distribute on the side vertical to the building direction. Some pores in with the maximum size of 100 μm exist of the structure. And there is no major influence for the build orientation on the tensile properties. The tensile strength and the elongation of the sample in the building direction are 340 Mpa and 11.2 % respectively. And the tensile strength and the elongation of the sample vertical to building direction are 350 Mpa and 13.4 % respectively

  9. Over-Selectivity as a Learned Response

    Science.gov (United States)

    Reed, Phil; Petrina, Neysa; McHugh, Louise

    2011-01-01

    An experiment investigated the effects of different levels of task complexity in pre-training on over-selectivity in a subsequent match-to-sample (MTS) task. Twenty human participants were divided into two groups; exposed either to a 3-element, or a 9-element, compound stimulus as a sample during MTS training. After the completion of training,…

  10. Clinical impact of strict criteria for selectivity and lateralization in adrenal vein sampling.

    Science.gov (United States)

    Gasparetto, Alessandro; Angle, John F; Darvishi, Pasha; Freeman, Colbey W; Norby, Ray G; Carey, Robert M

    2015-04-01

    Selectivity index (SI) and lateralization index (LI) thresholds determine the adequacy of adrenal vein sampling (AVS) and the degree of lateralization. The purpose of this study was investigate the clinical outcome of patients whose adrenal vein sampling was interpreted using "strict criteria" (SC) (SIpre-stimuli≥3, SIpost-stimuli≥5 and LIpre-stimuli≥4, LIpost-stimuli≥4). A retrospective review of 73 consecutive AVS procedures was performed and 67 were technically successful. Forty-three patients showed lateralization and underwent surgery, while 24 did not lateralize and were managed conservatively. Systolic blood pressure (SBP), diastolic blood pressure (DBP), kalemia (K(+)), and the change in number of blood pressure (BP) medications were recorded for each patient before and after AVS and potential surgery were performed. In the surgery group, BP and K(+) changed respectively from 160±5.3/100±2.0 mmHg to 127±3.3/80±1.9 (p blood pressure medications were six (14.0%) in the lateralized group and 22 (91.7%) in the non-lateralized group (p <0.001). AVS interpretation with SC leads to significant clinical improvement in both patients who underwent surgery and those managed conservatively.

  11. Factors influencing safety in a sample of marked pedestrian crossings selected for safety inspections in the city of Oslo.

    Science.gov (United States)

    Elvik, Rune; Sørensen, Michael W J; Nævestad, Tor-Olav

    2013-10-01

    This paper reports an analysis of factors influencing safety in a sample of marked pedestrian crossings in the city of Oslo, Norway. The sample consists of 159 marked pedestrian crossings where a total of 316 accidents were recorded during a period of five years. The crossings were selected for inspection because of they were, for various reasons, regarded as sub-standard. The sample of crossings is therefore not representative of all pedestrian crossings in Oslo. Factors influencing the number of accidents were studied by means of negative binomial regression. Factors that were studied included the volume of pedestrians and vehicles, the number of traffic lanes at the crossing, the location of the crossing (midblock or junction), the type of traffic control, the share of pedestrians using the crossing and the speed of approaching vehicles. The analysis confirmed the presence of a "safety-in-numbers" effect, meaning that an increase in the number of pedestrians is associated with a lower risk of accident for each pedestrian. Crossings located in four-leg junctions or roundabouts had more accidents than crossings located in three-leg junctions or on sections between junctions. A high share of pedestrians crossing the road outside the marked crossing was associated with a high number of accidents. Increased speed was associated with an increased number of accidents. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. The size selectivity of the main body of a sampling pelagic pair trawl in freshwater reservoirs during the night

    Czech Academy of Sciences Publication Activity Database

    Říha, Milan; Jůza, Tomáš; Prchalová, Marie; Mrkvička, Tomáš; Čech, Martin; Draštík, Vladislav; Muška, Milan; Kratochvíl, Michal; Peterka, Jiří; Tušer, Michal; Vašek, Mojmír; Kubečka, Jan

    2012-01-01

    Roč. 127, September (2012), s. 56-60 ISSN 0165-7836 R&D Projects: GA MZe(CZ) QH81046 Institutional support: RVO:60077344 Keywords : quantitative sampling * gear selectivity * trawl * reservoirs Subject RIV: GL - Fishing Impact factor: 1.695, year: 2012

  13. Independent assessment of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) sample preparation quality: Effect of sample preparation on MALDI-MS of synthetic polymers.

    Science.gov (United States)

    Kooijman, Pieter C; Kok, Sander; Honing, Maarten

    2017-02-28

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) provides detailed and in-depth information about the molecular characteristics of synthetic polymers. To obtain the most accurate results the sample preparation parameters should be chosen to suit the sample and the aim of the experiment. Because the underlying principles of MALDI are still not fully known, a priori determination of optimal sample preparation protocols is often not possible. Employing an automated sample preparation quality assessment method recently presented by us we quantified the sample preparation quality obtained using various sample preparation protocols. Six conventional matrices with and without added potassium as a cationization agent and six ionic liquid matrices (ILMs) were assessed using poly(ethylene glycol) (PEG), polytetrahydrofuran (PTHF) and poly(methyl methacrylate) (PMMA) as samples. All sample preparation protocols were scored and ranked based on predefined quality parameters and spot-to-spot repeatability. Clearly distinctive preferences were observed in matrix identity and cationization agent for PEG, PTHF and PMMA, as the addition of an excess of potassium cationization agent results in an increased score for PMMA and a contrasting matrix-dependent effect for PTHF and PEG. The addition of excess cationization agent to sample mixtures dissipates any overrepresentation of high molecular weight polymer species. Our results show reduced ionization efficiency and similar sample deposit homogeneity for all tested ILMs, compared with well-performing conventional MALDI matrices. The results published here represent a start in the unsupervised quantification of sample preparation quality for MALDI samples. This method can select the best sample preparation parameters for any synthetic polymer sample and the results can be used to formulate hypotheses on MALDI principles. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Enhanced Sampling and Analysis, Selection of Technology for Testing

    Energy Technology Data Exchange (ETDEWEB)

    Svoboda, John; Meikrantz, David

    2010-02-01

    The focus of this study includes the investigation of sampling technologies used in industry and their potential application to nuclear fuel processing. The goal is to identify innovative sampling methods using state of the art techniques that could evolve into the next generation sampling and analysis system for metallic elements. This report details the progress made in the first half of FY 2010 and includes a further consideration of the research focus and goals for this year. Our sampling options and focus for the next generation sampling method are presented along with the criteria used for choosing our path forward. We have decided to pursue the option of evaluating the feasibility of microcapillary based chips to remotely collect, transfer, track and supply microliters of sample solutions to analytical equipment in support of aqueous processes for used nuclear fuel cycles. Microchip vendors have been screened and a choice made for the development of a suitable microchip design followed by production of samples for evaluation by ANL, LANL, and INL on an independent basis.

  15. Selection effects and database screening in forensic science

    NARCIS (Netherlands)

    Meester, R.W.J.; Sjerps, M.

    2009-01-01

    We argue that it is, in principle, not difficult to deal with selection effects in forensic science. If a suspect is selected through a process that is related to the forensic evidence, then the strength of the evidence will be compensated by very small prior odds. No further correction is

  16. Correcting Classifiers for Sample Selection Bias in Two-Phase Case-Control Studies

    Science.gov (United States)

    Theis, Fabian J.

    2017-01-01

    Epidemiological studies often utilize stratified data in which rare outcomes or exposures are artificially enriched. This design can increase precision in association tests but distorts predictions when applying classifiers on nonstratified data. Several methods correct for this so-called sample selection bias, but their performance remains unclear especially for machine learning classifiers. With an emphasis on two-phase case-control studies, we aim to assess which corrections to perform in which setting and to obtain methods suitable for machine learning techniques, especially the random forest. We propose two new resampling-based methods to resemble the original data and covariance structure: stochastic inverse-probability oversampling and parametric inverse-probability bagging. We compare all techniques for the random forest and other classifiers, both theoretically and on simulated and real data. Empirical results show that the random forest profits from only the parametric inverse-probability bagging proposed by us. For other classifiers, correction is mostly advantageous, and methods perform uniformly. We discuss consequences of inappropriate distribution assumptions and reason for different behaviors between the random forest and other classifiers. In conclusion, we provide guidance for choosing correction methods when training classifiers on biased samples. For random forests, our method outperforms state-of-the-art procedures if distribution assumptions are roughly fulfilled. We provide our implementation in the R package sambia. PMID:29312464

  17. Highly selective ionic liquid-based microextraction method for sensitive trace cobalt determination in environmental and biological samples

    International Nuclear Information System (INIS)

    Berton, Paula; Wuilloud, Rodolfo G.

    2010-01-01

    A simple and rapid dispersive liquid-liquid microextraction procedure based on an ionic liquid (IL-DLLME) was developed for selective determination of cobalt (Co) with electrothermal atomic absorption spectrometry (ETAAS) detection. Cobalt was initially complexed with 1-nitroso-2-naphtol (1N2N) reagent at pH 4.0. The IL-DLLME procedure was then performed by using a few microliters of the room temperature ionic liquid (RTIL) 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6 mim][PF 6 ] as extractant while methanol was the dispersant solvent. After microextraction procedure, the Co-enriched RTIL phase was solubilized in methanol and directly injected into the graphite furnace. The effect of several variables on Co-1N2N complex formation, extraction with the dispersed RTIL phase, and analyte detection with ETAAS, was carefully studied in this work. An enrichment factor of 120 was obtained with only 6 mL of sample solution and under optimal experimental conditions. The resultant limit of detection (LOD) was 3.8 ng L -1 , while the relative standard deviation (RSD) was 3.4% (at 1 μg L -1 Co level and n = 10), calculated from the peak height of absorbance signals. The accuracy of the proposed methodology was tested by analysis of a certified reference material. The method was successfully applied for the determination of Co in environmental and biological samples.

  18. Effect of plastic deformation on the magnetic properties of selected austenitic stainless steels

    Directory of Open Access Journals (Sweden)

    Tatiana Oršulová

    2017-04-01

    Full Text Available Austenitic stainless steels are materials, that are widely used in various fields of industry, architecture and biomedicine. Their specific composition of alloying elements has got influence on their deformation behavior. The main goal of this study was evaluation of magnetic properties of selected steels, caused by plastic deformation. The samples were heat treated in different intervals of temperature before measuring. Then the magnetic properties were measured on device designed for measuring of magnetism. From tested specimens, only AISI 304 confirmed effect of plastic deformation on the magnetic properties. Magnetic properties changed with increasing temperature.

  19. Product-selective blot: a technique for measuring enzyme activities in large numbers of samples and in native electrophoresis gels

    International Nuclear Information System (INIS)

    Thompson, G.A.; Davies, H.M.; McDonald, N.

    1985-01-01

    A method termed product-selective blotting has been developed for screening large numbers of samples for enzyme activity. The technique is particularly well suited to detection of enzymes in native electrophoresis gels. The principle of the method was demonstrated by blotting samples from glutaminase or glutamate synthase reactions into an agarose gel embedded with ion-exchange resin under conditions favoring binding of product (glutamate) over substrates and other substances in the reaction mixture. After washes to remove these unbound substances, the product was measured using either fluorometric staining or radiometric techniques. Glutaminase activity in native electrophoresis gels was visualized by a related procedure in which substrates and products from reactions run in the electrophoresis gel were blotted directly into a resin-containing image gel. Considering the selective-binding materials available for use in the image gel, along with the possible detection systems, this method has potentially broad application

  20. Sampling strategies for estimating brook trout effective population size

    Science.gov (United States)

    Andrew R. Whiteley; Jason A. Coombs; Mark Hudy; Zachary Robinson; Keith H. Nislow; Benjamin H. Letcher

    2012-01-01

    The influence of sampling strategy on estimates of effective population size (Ne) from single-sample genetic methods has not been rigorously examined, though these methods are increasingly used. For headwater salmonids, spatially close kin association among age-0 individuals suggests that sampling strategy (number of individuals and location from...

  1. A simple highly sensitive and selective aptamer-based colorimetric sensor for environmental toxins microcystin-LR in water samples.

    Science.gov (United States)

    Li, Xiuyan; Cheng, Ruojie; Shi, Huijie; Tang, Bo; Xiao, Hanshuang; Zhao, Guohua

    2016-03-05

    A simple and highly sensitive aptamer-based colorimetric sensor was developed for selective detection of Microcystin-LR (MC-LR). The aptamer (ABA) was employed as recognition element which could bind MC-LR with high-affinity, while gold nanoparticles (AuNPs) worked as sensing materials whose plasma resonance absorption peaks red shifted upon binding of the targets at a high concentration of sodium chloride. With the addition of MC-LR, the random coil aptamer adsorbed on Au NPs altered into regulated structure to form MC-LR-aptamer complexes and broke away from the surface of Au NPs, leading to the aggregation of AuNPs, and the color converted from red to blue due to the interparticle plasmon coupling. Results showed that our aptamer-based colorimetric sensor exhibited rapid and sensitive detection performance for MC-LR with linear range from 0.5 nM to 7.5 μM and the detection limit reached 0.37 nM. Meanwhile, the pollutants usually coexisting with MC-LR in pollutant water samples had not demonstrated disturbance for detecting of MC-LR. The mechanism was also proposed suggesting that high affinity interaction between aptamer and MC-LR significantly enhanced the sensitivity and selectivity for MC-LR detection. Besides, the established method was utilized in analyzing real water samples and splendid sensitivity and selectivity were obtained as well. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Pesticides, selected elements, and other chemicals in adult total diet samples October 1979-September 1980

    International Nuclear Information System (INIS)

    Gartrell, M.J.; Craun, J.C.; Podrebarac, D.S.; Gunderson, E.L.

    1985-01-01

    The US Food and Drug Administration (FDA) conducts Total Diet Studies to determine the dietary intake of selected pesticides, industrial chemicals, and elements (including radionuclides). These studies involve the retail purchase and analysis of foods representative of the diets of infants, toddlers, and adults. The individual food items are separated into a number of food groups, each of which is analyzed as a composite. This report summarizes the results for adult Total Diet samples collected in 20 cities between October 1979 and September 1980. The average concentration, range of concentrations, and calculated average daily intake of each chemical found are presented by food group. The average daily intakes of the chemicals are similar to those found in the several preceding years and are within acceptable limits. The results for samples collected during the same period that represent the diets of infants and toddlers are reported separately

  3. Simulation of selected genealogies.

    Science.gov (United States)

    Slade, P F

    2000-02-01

    Algorithms for generating genealogies with selection conditional on the sample configuration of n genes in one-locus, two-allele haploid and diploid models are presented. Enhanced integro-recursions using the ancestral selection graph, introduced by S. M. Krone and C. Neuhauser (1997, Theor. Popul. Biol. 51, 210-237), which is the non-neutral analogue of the coalescent, enables accessible simulation of the embedded genealogy. A Monte Carlo simulation scheme based on that of R. C. Griffiths and S. Tavaré (1996, Math. Comput. Modelling 23, 141-158), is adopted to consider the estimation of ancestral times under selection. Simulations show that selection alters the expected depth of the conditional ancestral trees, depending on a mutation-selection balance. As a consequence, branch lengths are shown to be an ineffective criterion for detecting the presence of selection. Several examples are given which quantify the effects of selection on the conditional expected time to the most recent common ancestor. Copyright 2000 Academic Press.

  4. Effect of optimum stratification on sampling with varying probabilities under proportional allocation

    Directory of Open Access Journals (Sweden)

    Syed Ejaz Husain Rizvi

    2007-10-01

    Full Text Available The problem of optimum stratification on an auxiliary variable when the units from different strata are selected with probability proportional to the value of auxiliary variable (PPSWR was considered by Singh (1975 for univariate case. In this paper we have extended the same problem, for proportional allocation, when two variates are under study. A cum. 3 R3(x rule for obtaining approximately optimum strata boundaries has been provided. It has been shown theoretically as well as empirically that the use of stratification has inverse effect on the relative efficiency of PPSWR as compared to unstratified PPSWR method when proportional method of allocation is envisaged. Further comparison showed that with increase in number of strata the stratified simple random sampling is equally efficient as PPSWR.

  5. Sample Selection for Training Cascade Detectors

    OpenAIRE

    V?llez, Noelia; Deniz, Oscar; Bueno, Gloria

    2015-01-01

    Automatic detection systems usually require large and representative training datasets in order to obtain good detection and false positive rates. Training datasets are such that the positive set has few samples and/or the negative set should represent anything except the object of interest. In this respect, the negative set typically contains orders of magnitude more images than the positive set. However, imbalanced training databases lead to biased classifiers. In this paper, we focus our a...

  6. Analysis of Selected Legacy 85Kr Samples

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-02

    Legacy samples composed of 85Kr encapsulated in solid zeolite 5A material and five small metal tubes containing a mixture of the zeolite combined with a glass matrix resulting from hot isostatic pressing have been preserved. The samples were a result of krypton R&D encapsulation efforts in the late 1970s performed at the Idaho Chemical Processing Plant. These samples were shipped to Oak Ridge National Laboratory (ORNL) in mid-FY 2014. Upon receipt the outer shipping package was opened, and the inner package, removed and placed in a radiological hood. The individual capsules were double bagged as they were removed from the inner shipping pig and placed into individual glass sample bottles for further analysis. The five capsules were then x-ray imaged. Capsules 1 and 4 appear intact and to contain an amorphous mass within the capsules. Capsule 2 clearly shows the saw marks on the capsule and a quantity of loose pellet or bead-like material remaining in the capsule. Capsule 3 shows similar bead-like material within the intact capsule. Capsule 5 had been opened at an undetermined time in the past. The end of this capsule appears to have been cut off, and there are additional saw marks on the side of the capsule. X-ray tomography allowed the capsules to be viewed along the three axes. Of most interest was determining whether there was any residual material in the closed end of Capsule 5. The images confirmed the presence of residual material within this capsule. The material appears to be compacted but still retains some of the bead-like morphology. Based on the nondestructive analysis (NDA) results, a proposed path forward was formulated to advance this effort toward the original goals of understanding the effects of extended storage on the waste form and package. Based on the initial NDA and the fact that there are at least two breached samples, it was proposed that exploratory tests be conducted with the breached specimens before opening the three intact

  7. Rational approach to solvent system selection for liquid-liquid extraction-assisted sample pretreatment in counter-current chromatography.

    Science.gov (United States)

    Wang, Jiajia; Gu, Dongyu; Wang, Miao; Guo, Xinfeng; Li, Haoquan; Dong, Yue; Guo, Hong; Wang, Yi; Fan, Mengqi; Yang, Yi

    2017-05-15

    A rational liquid-liquid extraction approach was established to pre-treat samples for high-speed counter-current chromatography (HSCCC). n-Hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) and (1:5:1:5, v/v) were selected as solvent systems for liquid-liquid extraction by systematically screening K of target compounds to remove low- and high-polarity impurities in the sample, respectively. After liquid-liquid extraction was performed, 1.4g of crude sample II was obtained from 18.5g of crude sample I which was extracted from the flowers of Robinia pseudoacacia L., and then separated with HSCCC by using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v). As a result, 31mg of robinin and 37mg of kaempferol 7-O-α-l-rhamnopyranoside were isolated from 200mg of crude sample II in a single run of HSCCC. A scale-up separation was also performed, and 160mg of robinin with 95% purity and 188mg of kaempferol 7-O-α-l-rhamnopyranoside with 97% purity were produced from 1.2g of crude sample II. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Assessing Generative Braille Responding Following Training in a Matching-to-Sample Format

    Science.gov (United States)

    Putnam, Brittany C.; Tiger, Jeffrey H.

    2016-01-01

    We evaluated the effects of teaching sighted college students to select printed text letters given a braille sample stimulus in a matching-to-sample (MTS) format on the emergence of untrained (a) construction of print characters given braille samples, (b) construction of braille characters given print samples, (c) transcription of print characters…

  9. Response selection difficulty modulates the behavioral impact of rapidly learnt action effects.

    Directory of Open Access Journals (Sweden)

    Uta eWolfensteller

    2014-12-01

    Full Text Available It is well established that we can pick up action effect associations when acting in a free-choice intentional mode. However, it is less clear whether and when action effect associations are learnt and actually affect behavior if we are acting in a forced-choice mode, applying a specific stimulus-response (S-R rule. In the present study, we investigated whether response selection difficulty imposed by S-R rules influences the initial rapid learning and the behavioral expression of previously learnt but weakly practiced action effect associations when those are re-activated by effect exposure. Experiment 1 showed that the rapid acquisition of action effect associations is not directly influenced by response selection difficulty. By contrast, the behavioral expression of re-activated action effect associations is prevented when actions are directly activated by highly over-learnt response cues and thus response selection difficulty is low. However, all three experiments showed that if response selection difficulty is sufficiently high during re-activation, the same action effect associations do influence behavior. Experiment 2 and 3 revealed that the effect of response selection difficulty cannot be fully reduced to giving action effects more time to prime an action, but seems to reflect competition during response selection. Finally, the present data suggest that when multiple novel rules are rapidly learnt in succession, which requires a lot of flexibility, action effect associations continue to influence behavior only if response selection difficulty is sufficiently high. Thus, response selection difficulty might modulate the impact of experiencing multiple learning episodes on action effect expression and learning, possibly via inducing different strategies.

  10. Effect of microwave irradiation on selective heating behavior and magnetic separation characteristics of Panzhihua ilmenite

    International Nuclear Information System (INIS)

    Zhao, Wei; Chen, Jin; Chang, Xiaodong; Guo, Shenghui; Srinivasakannan, C.; Chen, Guo; Peng, Jinhui

    2014-01-01

    Highlights: • Microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite. • The mineral processing properties of microwave treated ilmenite were generally as good as or better than that of initial ilmenite. • The microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. - Abstract: The influences of microwave irradiation on the surface characteristics of Panzhihua ilmenite were systematically investigated. The crystal structures, surface morphology and surface chemical functional groups of ilmenite were characterized before and after microwave irradiation and magnetic separation for different microwave treatment times by using various methods, such as XRD, SEM, and FT-IR, respectively. XRD analysis showed that the microwave treated ilmenite has the strongest peaks of phase more than that of raw samples, indicates that the crystalline compound of ilmenite increased with the microwave irradiation time. SEM analysis showed the micro-cracking appeared at many grain boundaries of ilmenite after being pretreated by microwave treatment. The separations of ilmenite from gangue minerals were completed and the micro-fissure within ilmenite minerals were also formed, which could be attributed to the microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. The mineral processing results showed that the magnetic separation characteristics and properties of microwave treated ilmenite samples were better than that of microwave untreated ilmenite samples. It was concluded that microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite

  11. Portable, universal, and visual ion sensing platform based on the light emitting diode-based self-referencing-ion selective field-effect transistor.

    Science.gov (United States)

    Zhang, Xiaowei; Han, Yanchao; Li, Jing; Zhang, Libing; Jia, Xiaofang; Wang, Erkang

    2014-02-04

    In this work, a novel and universal ion sensing platform was presented, which enables the visual detection of various ions with high sensitivity and selectivity. Coaxial potential signals (millivolt-scale) of the sample from the self-referencing (SR) ion selective chip can be transferred into the ad620-based amplifier with an output of volt-scale potentials. The amplified voltage is high enough to drive a light emitting diode (LED), which can be used as an amplifier and indicator to report the sample information. With this double amplification device (light emitting diode-based self-referencing-ion selective field-effect transistor, LED-SR-ISFET), a tiny change of the sample concentration can be observed with a distinguishable variation of LED brightness by visual inspection. This LED-based luminescent platform provided a facile, low-cost, and rapid sensing strategy without the need of additional expensive chemiluminescence reagent and instruments. Moreover, the SR mode also endows this device excellent stability and reliability. With this innovative design, sensitive determination of K(+), H(+), and Cl(-) by the naked eye was achieved. It should also be noticed that this sensing strategy can easily be extended to other ions (or molecules) by simply integrating the corresponding ion (or molecule) selective electrode.

  12. Factors in selecting serum samples for use in determining the positive/negative threshold (cut-off) in ELISA

    International Nuclear Information System (INIS)

    Jacobson, R.H.

    1998-01-01

    The threshold (cut-off) that defines whether a test result is seropositive or seronegative is calculated by testing serum samples from a subpopulation of animals that is assumed to represent the target population in all aspects. For this proposition to be true, it is essential to consider the variables in the target population that must be represented in the subpopulation. Without representation of the variables in the subpopulation, it is likely that the cut-off selected for the test will be errant and will misclassify animals as to their infection status. The purpose of this paper is to identify a few of the principal variables that need to be taken into account when selecting a subpopulation of animals for test validation. (author)

  13. The effect of selection on genetic parameter estimates

    African Journals Online (AJOL)

    Unknown

    The South African Journal of Animal Science is available online at ... A simulation study was carried out to investigate the effect of selection on the estimation of genetic ... The model contained a fixed effect, random genetic and random.

  14. A Simple Analytical Method Using HPLC with Fluorescence Detection to Determine Selected Polycyclic Aromatic Compounds in Filter Samples

    International Nuclear Information System (INIS)

    Garcia, S.; Perez, R. M.

    2014-01-01

    A study on the comparison and evaluation of a miniaturized extraction method for the determination of selected PACs in sample filters is presented. The main objective was the optimization and development of simple, rapid and low cost methods, minimizing the use of extracting solvent volume. The work also includes a study on the intermediate precision. (Author)

  15. The effects of sampling bias and model complexity on the predictive performance of MaxEnt species distribution models.

    Science.gov (United States)

    Syfert, Mindy M; Smith, Matthew J; Coomes, David A

    2013-01-01

    Species distribution models (SDMs) trained on presence-only data are frequently used in ecological research and conservation planning. However, users of SDM software are faced with a variety of options, and it is not always obvious how selecting one option over another will affect model performance. Working with MaxEnt software and with tree fern presence data from New Zealand, we assessed whether (a) choosing to correct for geographical sampling bias and (b) using complex environmental response curves have strong effects on goodness of fit. SDMs were trained on tree fern data, obtained from an online biodiversity data portal, with two sources that differed in size and geographical sampling bias: a small, widely-distributed set of herbarium specimens and a large, spatially clustered set of ecological survey records. We attempted to correct for geographical sampling bias by incorporating sampling bias grids in the SDMs, created from all georeferenced vascular plants in the datasets, and explored model complexity issues by fitting a wide variety of environmental response curves (known as "feature types" in MaxEnt). In each case, goodness of fit was assessed by comparing predicted range maps with tree fern presences and absences using an independent national dataset to validate the SDMs. We found that correcting for geographical sampling bias led to major improvements in goodness of fit, but did not entirely resolve the problem: predictions made with clustered ecological data were inferior to those made with the herbarium dataset, even after sampling bias correction. We also found that the choice of feature type had negligible effects on predictive performance, indicating that simple feature types may be sufficient once sampling bias is accounted for. Our study emphasizes the importance of reducing geographical sampling bias, where possible, in datasets used to train SDMs, and the effectiveness and essentialness of sampling bias correction within MaxEnt.

  16. Source apportionment and location by selective wind sampling and Positive Matrix Factorization.

    Science.gov (United States)

    Venturini, Elisa; Vassura, Ivano; Raffo, Simona; Ferroni, Laura; Bernardi, Elena; Passarini, Fabrizio

    2014-10-01

    In order to determine the pollution sources in a suburban area and identify the main direction of their origin, PM2.5 was collected with samplers coupled with a wind select sensor and then subjected to Positive Matrix Factorization (PMF) analysis. In each sample, soluble ions, organic carbon, elemental carbon, levoglucosan, metals, and Polycyclic Aromatic Hydrocarbons (PAHs) were determined. PMF results identified six main sources affecting the area: natural gas home appliances, motor vehicles, regional transport, biomass combustion, manufacturing activities, and secondary aerosol. The connection of factor temporal trends with other parameters (i.e., temperature, PM2.5 concentration, and photochemical processes) confirms factor attributions. PMF analysis indicated that the main source of PM2.5 in the area is secondary aerosol. This should be mainly due to regional contributions, owing to both the secondary nature of the source itself and the higher concentration registered in inland air masses. The motor vehicle emission source contribution is also important. This source likely has a prevalent local origin. The most toxic determined components, i.e., PAHs, Cd, Pb, and Ni, are mainly due to vehicular traffic. Even if this is not the main source in the study area, it is the one of greatest concern. The application of PMF analysis to PM2.5 collected with this new sampling technique made it possible to obtain more detailed results on the sources affecting the area compared to a classical PMF analysis.

  17. Relay selection from an effective capacity perspective

    KAUST Repository

    Yang, Yuli

    2013-09-01

    In this work, we consider a cooperative network where multiple relay nodes having different modulation capabilities assist the end-to-end communication between a source and its destination. Firstly, we evaluate the effective capacity (EC) performance of the network under study. According to the analysis, an EC-based relay selection criterion is proposed. Based on the proposed selection rule and half-duplex decode-and-forward protocol, the activated relays cooperatively help with the packet transmission from the source. At the destination, packet combining is taken into account to improve the quality of service. Compared to the popular scheme, opportunistic relay selection, numerical results are provided to prove the validity and advantages of our proposed scheme in certain scenarios. Moreover, the analysis presented herein offers a convenient tool to the relaying transmission design, specifically on which relay selection scheme should be used as well as how to choose the receiving strategy between with and without packet combining at the destination. © 2013 IEEE.

  18. Selective effects of cholinergic modulation on task performance during selective attention.

    Science.gov (United States)

    Furey, Maura L; Pietrini, Pietro; Haxby, James V; Drevets, Wayne C

    2008-03-01

    The cholinergic neurotransmitter system is critically linked to cognitive functions including attention. The current studies were designed to evaluate the effect of a cholinergic agonist and an antagonist on performance during a selective visual attention task where the inherent salience of attended/unattended stimuli was modulated. Two randomized, placebo-controlled, crossover studies were performed, one (n=9) with the anticholinesterase physostigmine (1.0 mg/h), and the other (n=30) with the anticholinergic scopolamine (0.4 mc/kg). During the task, two double-exposure pictures of faces and houses were presented side by side. Subjects were cued to attend to either the face or the house component of the stimuli, and were instructed to perform a matching task with the two exemplars from the attended category. The cue changed every 4-7 trials to instruct subjects to shift attention from one stimulus component to the other. During placebo in both studies, reaction time (RT) associated with the first trial following a cued shift in attention was longer than RT associated with later trials (pattention to houses condition (pattention to faces. Scopolamine increased RT relative to placebo selectively during trials greater than one (pattention to faces condition (pselective attention (ie trials greater than 1). Moreover, effects of cholinergic manipulation depend on the selective attention condition (ie faces vs houses), which may suggest that cholinergic activity interacts with stimulus salience. The findings are discussed within the context of the role of acetylcholine both in stimulus processing and stimulus salience, and in establishing attention biases through top-down and bottom-up mechanisms of attention.

  19. Optimal Subset Selection of Time-Series MODIS Images and Sample Data Transfer with Random Forests for Supervised Classification Modelling.

    Science.gov (United States)

    Zhou, Fuqun; Zhang, Aining

    2016-10-25

    Nowadays, various time-series Earth Observation data with multiple bands are freely available, such as Moderate Resolution Imaging Spectroradiometer (MODIS) datasets including 8-day composites from NASA, and 10-day composites from the Canada Centre for Remote Sensing (CCRS). It is challenging to efficiently use these time-series MODIS datasets for long-term environmental monitoring due to their vast volume and information redundancy. This challenge will be greater when Sentinel 2-3 data become available. Another challenge that researchers face is the lack of in-situ data for supervised modelling, especially for time-series data analysis. In this study, we attempt to tackle the two important issues with a case study of land cover mapping using CCRS 10-day MODIS composites with the help of Random Forests' features: variable importance, outlier identification. The variable importance feature is used to analyze and select optimal subsets of time-series MODIS imagery for efficient land cover mapping, and the outlier identification feature is utilized for transferring sample data available from one year to an adjacent year for supervised classification modelling. The results of the case study of agricultural land cover classification at a regional scale show that using only about a half of the variables we can achieve land cover classification accuracy close to that generated using the full dataset. The proposed simple but effective solution of sample transferring could make supervised modelling possible for applications lacking sample data.

  20. Distribution of Gas Phase Polycyclic Aromatic Hydrocarbons (PAHs in Selected Indoor and Outdoor Air Samples of Malaysia: a Case Study in Serdang, Selangor and Bachang, Malacca

    Directory of Open Access Journals (Sweden)

    Haris Hafizal Abd Hamid

    2017-07-01

    Full Text Available Distribution of 10 polycyclic aromatic hydrocarbons (PAHs in the gas phase of air from selected indoor and outdoor areas of Selangor and Malacca, Malaysia has been investigated. A locally designed Semi Permeable Membrane Device (SPMD was applied for passive air sampling for 37 days at selected locations. Cleanup was carried out with Gas Purge - Micro Syringe Extraction (GP-MSE and the final analysis was using Gas Chromatography-Mass Spectrometry (GC-MS. In this study, 6 indoor and 12 outdoor locations were selected for air sampling. A total of 10 compounds of PAHs (Ʃ10PAHs were determined in the range of 0.218 ng/m3 - 1.692 ng/m3 and 0.378 ng/m3 - 1.492 ng/m3 in outdoor and indoor samples respectively. In the outdoor samples, locations such as near a petrol station and heavy traffic showed the maximum levels of Ʃ10PAHs, while rooftop samples showed the lowest Ʃ10PAHs. The distribution of gas phase Ʃ10PAHs was influenced by vehicular emission. Low molecular weight (LMW compounds (2-3 rings were dominant in all samples (>70% indicating that SPMD has successfully sampled the gas phase of the air.

  1. Evaluation of pump pulsation in respirable size-selective sampling: Part III. Investigation of European standard methods.

    Science.gov (United States)

    Soo, Jhy-Charm; Lee, Eun Gyung; Lee, Larry A; Kashon, Michael L; Harper, Martin

    2014-10-01

    Lee et al. (Evaluation of pump pulsation in respirable size-selective sampling: part I. Pulsation measurements. Ann Occup Hyg 2014a;58:60-73) introduced an approach to measure pump pulsation (PP) using a real-world sampling train, while the European Standards (EN) (EN 1232-1997 and EN 12919-1999) suggest measuring PP using a resistor in place of the sampler. The goal of this study is to characterize PP according to both EN methods and to determine the relationship of PP between the published method (Lee et al., 2014a) and the EN methods. Additional test parameters were investigated to determine whether the test conditions suggested by the EN methods were appropriate for measuring pulsations. Experiments were conducted using a factorial combination of personal sampling pumps (six medium- and two high-volumetric flow rate pumps), back pressures (six medium- and seven high-flow rate pumps), resistors (two types), tubing lengths between a pump and resistor (60 and 90 cm), and different flow rates (2 and 2.5 l min(-1) for the medium- and 4.4, 10, and 11.2 l min(-1) for the high-flow rate pumps). The selection of sampling pumps and the ranges of back pressure were based on measurements obtained in the previous study (Lee et al., 2014a). Among six medium-flow rate pumps, only the Gilian5000 and the Apex IS conformed to the 10% criterion specified in EN 1232-1997. Although the AirChek XR5000 exceeded the 10% limit, the average PP (10.9%) was close to the criterion. One high-flow rate pump, the Legacy (PP=8.1%), conformed to the 10% criterion in EN 12919-1999, while the Elite12 did not (PP=18.3%). Conducting supplemental tests with additional test parameters beyond those used in the two subject EN standards did not strengthen the characterization of PPs. For the selected test conditions, a linear regression model [PPEN=0.014+0.375×PPNIOSH (adjusted R2=0.871)] was developed to determine the PP relationship between the published method (Lee et al., 2014a) and the EN methods

  2. Sampling or gambling

    Energy Technology Data Exchange (ETDEWEB)

    Gy, P.M.

    1981-12-01

    Sampling can be compared to no other technique. A mechanical sampler must above all be selected according to its aptitude for supressing or reducing all components of the sampling error. Sampling is said to be correct when it gives all elements making up the batch of matter submitted to sampling an uniform probability of being selected. A sampler must be correctly designed, built, installed, operated and maintained. When the conditions of sampling correctness are not strictly respected, the sampling error can no longer be controlled and can, unknown to the user, be unacceptably large: the sample is no longer representative. The implementation of an incorrect sampler is a form of gambling and this paper intends to show that at this game the user is nearly always the loser in the long run. The users' and the manufacturers' interests may diverge and the standards which should safeguard the users' interests very often fail to do so by tolerating or even recommending incorrect techniques such as the implementation of too narrow cutters traveling too fast through the stream to be sampled.

  3. The effect of sexual selection on adaptation and extinction under increasing temperatures.

    Science.gov (United States)

    Parrett, Jonathan M; Knell, Robert J

    2018-04-25

    Strong sexual selection has been reported to both enhance and hinder the adaptive capacity and persistence of populations when exposed to novel environments. Consequently, how sexual selection influences population adaption and persistence under stress remains widely debated. Here, we present two empirical investigations of the fitness consequences of sexual selection on populations of the Indian meal moth, Plodia interpunctella, exposed to stable or gradually increasing temperatures. When faced with increasing temperatures, strong sexual selection was associated with both increased fecundity and offspring survival compared with populations experiencing weak sexual selection, suggesting sexual selection acts to drive adaptive evolution by favouring beneficial alleles. Strong sexual selection did not, however, delay extinction when the temperature became excessively high. By manipulating individuals' mating opportunities during fitness assays, we were able to assess the effect of multiple mating independently from the effect of population-level sexual selection, and found that polyandry has a positive effect on both fecundity and offspring survival under increasing temperatures in those populations evolving with weak sexual selection. Within stable temperatures, there were some benefits from strong sexual selection but these were not consistent across the entire experiment, possibly reflecting changing costs and benefits of sexual selection under stabilizing and directional selection. These results indicate that sexual selection can provide a buffer against climate change and increase adaptation rates within a continuously changing environment. These positive effects of sexual selection may, however, be too small to protect populations and delay extinction when environmental changes are relatively rapid. © 2018 The Author(s).

  4. A Fast Algorithm of Convex Hull Vertices Selection for Online Classification.

    Science.gov (United States)

    Ding, Shuguang; Nie, Xiangli; Qiao, Hong; Zhang, Bo

    2018-04-01

    Reducing samples through convex hull vertices selection (CHVS) within each class is an important and effective method for online classification problems, since the classifier can be trained rapidly with the selected samples. However, the process of CHVS is NP-hard. In this paper, we propose a fast algorithm to select the convex hull vertices, based on the convex hull decomposition and the property of projection. In the proposed algorithm, the quadratic minimization problem of computing the distance between a point and a convex hull is converted into a linear equation problem with a low computational complexity. When the data dimension is high, an approximate, instead of exact, convex hull is allowed to be selected by setting an appropriate termination condition in order to delete more nonimportant samples. In addition, the impact of outliers is also considered, and the proposed algorithm is improved by deleting the outliers in the initial procedure. Furthermore, a dimension convention technique via the kernel trick is used to deal with nonlinearly separable problems. An upper bound is theoretically proved for the difference between the support vector machines based on the approximate convex hull vertices selected and all the training samples. Experimental results on both synthetic and real data sets show the effectiveness and validity of the proposed algorithm.

  5. Sample selection may bias the outcome of an adolescent mental health survey: results from a five-year follow-up of 4171 adolescents.

    Science.gov (United States)

    Kekkonen, V; Kivimäki, P; Valtonen, H; Hintikka, J; Tolmunen, T; Lehto, S M; Laukkanen, E

    2015-02-01

    The representativeness of the data is one of the main issues in evaluating the significance of research findings. Dropping out is common in adolescent mental health research, and may distort the results. Nevertheless, very little is known about the types of systematic bias that may affect studies in a) the informed consent phase and b) later in follow-up phases. The authors addressed this gap in knowledge in a five-year follow-up study on a sample of adolescents aged 13-18 years. The data were collected using self-report questionnaires. The baseline sample consisted of 4171 adolescents, 1827 (43.8%) of whom gave consent to be contacted for a follow-up survey, but only 797 (19.1%) participated in the follow-up. Binary logistic regression models were used to explain the participation. Young age, female gender, a high number of hobbies, good performance at school in the native language and general subjects, family disintegration such as divorce, high parental employment, and symptoms of depression and anxiety were associated with both consent and participation. However, the effect of mental health aspects was smaller than the effect of age and gender. This study confirmed the possibility of systematic selection bias by adolescents' sociodemographic characteristics. The representativeness of the study sample might have been improved by more intense recruitment strategies. Copyright © 2014 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  6. AID SELECTIVITY PRACTICE AND AID EFFECTIVENESS IN SUB-SAHARAN AFRICA

    OpenAIRE

    Adedokun, Adeniyi Jimmy; Abiodun O. Folawewo, Abiodun O.

    2017-01-01

    Foreign aid strategies have undergone restructuring as donors adopt aid selectivity practice to improve aid effectiveness. This study investigates the impact of aid selectivity practice on aid effectiveness (aid-growth relationship) in Sub-Saharan Africa (SSA) and several groups of countries within SSA from 1980 to 2012. Employing system generalized methods of moments (system GMM) technique; the study produces strong evidence that there is significant improvement in aid effectiveness due to a...

  7. Model selection with multiple regression on distance matrices leads to incorrect inferences.

    Directory of Open Access Journals (Sweden)

    Ryan P Franckowiak

    Full Text Available In landscape genetics, model selection procedures based on Information Theoretic and Bayesian principles have been used with multiple regression on distance matrices (MRM to test the relationship between multiple vectors of pairwise genetic, geographic, and environmental distance. Using Monte Carlo simulations, we examined the ability of model selection criteria based on Akaike's information criterion (AIC, its small-sample correction (AICc, and the Bayesian information criterion (BIC to reliably rank candidate models when applied with MRM while varying the sample size. The results showed a serious problem: all three criteria exhibit a systematic bias toward selecting unnecessarily complex models containing spurious random variables and erroneously suggest a high level of support for the incorrectly ranked best model. These problems effectively increased with increasing sample size. The failure of AIC, AICc, and BIC was likely driven by the inflated sample size and different sum-of-squares partitioned by MRM, and the resulting effect on delta values. Based on these findings, we strongly discourage the continued application of AIC, AICc, and BIC for model selection with MRM.

  8. Effects of sample size on the second magnetization peak in ...

    Indian Academy of Sciences (India)

    the sample size decreases – a result that could be interpreted as a size effect in the order– disorder vortex matter phase transition. However, local magnetic measurements trace this effect to metastable disordered vortex states, revealing the same order–disorder transition induction in samples of different size. Keywords.

  9. The effect of local heat on term neonates pain intensity during heel-blood sampling

    Directory of Open Access Journals (Sweden)

    R. GHobadi Mohebi

    2017-04-01

    Full Text Available Aims: Newborns are more sensitive to pain than adults and are more susceptible to the long-term complications of pain. So, it is necessary to use procedures for reducing pain in newborns. The aim of this study was to determine the effect of local heat on the pain intensity of heel-blood sampling in the term newborns. Material & Methods: In this randomized controlled clinical trial study, in 2012, 63 healthy 3 to 5-day newborns who were referred to Shahid Delkhah Health Center in Ferdows were selected by random sampling method and randomly divided into 3 groups (21 people in each group: test (heat, placebo (sound and control. The pain intensity of newborns before, during and after heel-blood sampling was evaluated. The data collection tools were demographic questionnaire and Neonatal Infant Pain Scale (NIPS. Data were analyzed by SPSS 14.5 software and chi-square test, one-way ANOVA, Tukey's post hoc test, and ANOVA with repeated observations. Finding: The mean pain intensity in the three groups was not significantly different before intervention (p=0.86, but the mean pain intensity was lower in the test group than in the other two groups (p=0.006. After heel-blood sampling, the mean pain intensity was the least in the test group and was the most in the control group (p<0.001. Conclusion: Local heat during and after heel blood sampling decreases pain intensity in the term newborns.

  10. Selection effects in the bivariate brightness distribution for spiral galaxies

    International Nuclear Information System (INIS)

    Phillipps, S.; Disney, M.

    1986-01-01

    The joint distribution of total luminosity and characteristic surface brightness (the bivariate brightness distribution) is investigated for a complete sample of spiral galaxies in the Virgo cluster. The influence of selection and physical limits of various kinds on the apparent distribution are detailed. While the distribution of surface brightness for bright galaxies may be genuinely fairly narrow, faint galaxies exist right across the (quite small) range of accessible surface brightnesses so no statement can be made about the true extent of the distribution. The lack of high surface brightness bright galaxies in the Virgo sample relative to an overall RC2 sample (mostly field galaxies) supports the contention that the star-formation rate is reduced in the inner region of the cluster for environmental reasons. (author)

  11. Selective trace enrichment of chlorotriazine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers

    Science.gov (United States)

    Ferrer, I.; Lanza, F.; Tolokan, A.; Horvath, V.; Sellergren, B.; Horvai, G.; Barcelo, D.

    2000-01-01

    Two molecularly imprinted polymers were synthesized using either dichloromethane or toluene as the porogen and terbuthylazine as the template and were used as solid-phase extraction cartridges for the enrichment of six chlorotriazines (deisopropylatrazine, deethylatrazine, simazine, atrazine, propazine, and terbuthylazine) in natural water and sediment samples. The extracted samples were analyzed by liquid chromatography/diode array detection (LC/DAD). Several washing solvents, as well as different volumes, were tested for their ability to remove the matrix components nonspecifically adsorbed on the sorbents. This cleanup step was shown to be of prime importance to the successful extraction of the pesticides from the aqueous samples. The optimal analytical conditions were obtained when the MIP imprinted using dichloromethane was the sorbent, 2 mL of dichloromethane was used in the washing step, and the preconcentrated analytes were eluted with 8 mL of methanol. The recoveries were higher than 80% for all the chlorotriazines except for propazine (53%) when 50- or 100-mL groundwater samples, spiked at 1 ??g/L level, were analyzed. The limits of detection varied from 0.05 to 0.2 ??g/L when preconcentrating a 100-mL groundwater sample. Natural sediment samples from the Ebre Delta area (Tarragona, Spain) containing atrazine and deethylatrazine were Soxhlet extracted and analyzed by the methodology developed in this work. No significant interferences from the sample matrix were noticed, thus indicating good selectivity of the MIP sorbents used.

  12. On some common practices of systematic sampling

    OpenAIRE

    Zhang, Li-Chun

    2006-01-01

    With permission from Statistics Sweden. The original publication is available at http://www.jos.nu/Contents/jos_online.asp Artikkelen er også utgitt i Statistisk sentralbyrås serie Særtrykk/Reprints nr 325. Systematic sampling is widely used technique in survey sampling. It is easy to execute, whether the units are to be selected with equal probability or with probabilities proportional to auxiliary sizes. It can be very efficient if one manage to achieve favourable stratification effect...

  13. Valley-selective optical Stark effect probed by Kerr rotation

    Science.gov (United States)

    LaMountain, Trevor; Bergeron, Hadallia; Balla, Itamar; Stanev, Teodor K.; Hersam, Mark C.; Stern, Nathaniel P.

    2018-01-01

    The ability to monitor and control distinct states is at the heart of emerging quantum technologies. The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for such control, with the optical Stark effect allowing for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-sensitive optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. More sensitive polarization-based spectroscopy is required to better probe ultrafast Stark shifts for all-optical manipulation of valley energy levels. Here, we show time-resolved Kerr rotation to be a more sensitive probe of the valley-selective optical Stark effect in monolayer TMDCs. Compared to the established time-resolved reflectance methods, Kerr rotation is less sensitive to background effects. Kerr rotation provides a fivefold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley and energy selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.

  14. Determination of Nd3+ Ions in Solution Samples by a Coated Wire Ion-Selective Sensor

    Directory of Open Access Journals (Sweden)

    Hassan Ali Zamani

    2012-01-01

    Full Text Available A new coated wire electrode (CWE using 5-(methylsulfanyl-3-phenyl-1H-1,2,4-triazole (MPT as an ionophore has been developed as a neodymium ion-selective sensor. The sensor exhibits Nernstian response for the Nd3+ ions in the concentration range of 1.0×10−6-1.0×10−2 M with detection limit of 3.7×10−7 M. It displays a Nernstian slope of 20.2±0.2 mV/decade in the pH range of 2.7–8.1. The proposed sensor also exhibits a fast response time of ∼5 s. The sensor revealed high selectivity with respect to all common alkali, alkaline earth, transition and heavy metal ions, including members of the lanthanide family other than Nd3+. The electrode was used as an indicator electrode in the potentiometric titration of Nd(III ions with EDTA. The electrode was also employed for the determination of the Nd3+ ions concentration in water solution samples.

  15. Methodology Series Module 5: Sampling Strategies

    OpenAIRE

    Setia, Maninder Singh

    2016-01-01

    Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ? Sampling Method?. There are essentially two types of sampling methods: 1) probability sampling ? based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling ? based on researcher's choice, population that accessible & available. Some of the non-probabilit...

  16. Recurrent pain is associated with decreased selective attention in a population-based sample.

    Science.gov (United States)

    Gijsen, C P; Dijkstra, J B; van Boxtel, M P J

    2011-01-01

    Studies which have examined the impact of pain on cognitive functioning in the general population are scarce. In the present study we assessed the predictive value of recurrent pain on cognitive functioning in a population-based study (N=1400). Furthermore, we investigated the effect of pain on cognitive functioning in individuals with specific pain complaints (i.e. back pain, gastric pain, muscle pain and headache). Cognitive functioning was assessed using the Stroop Color-Word Interference test (Stroop interference), the Letter-Digit-Substitution test (LDST) and the Visual Verbal learning Task (VVLT). Pain was measured with the COOP/WONCA pain scale (Dartmouth Primary Care Cooperative Information Project/World Organization of National Colleges, Academies, and Academic Associations of General Practice /Family Physicians). We controlled for the effects of age, sex, level of education and depressive symptoms. It was demonstrated that pain had a negative impact on the performance on the Stroop interference but not on the VVLT and the LDST. This indicates that subjects who reported extreme pain had more problems with selective attention and were more easily distracted. Effects were in general larger in the specific pain groups when compared to the associations found in the total group. Implications of these findings are discussed. The experience of recurrent pain has a negative influence on selective attention in a healthy population. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  17. Directional selection in temporally replicated studies is remarkably consistent.

    Science.gov (United States)

    Morrissey, Michael B; Hadfield, Jarrod D

    2012-02-01

    Temporal variation in selection is a fundamental determinant of evolutionary outcomes. A recent paper presented a synthetic analysis of temporal variation in selection in natural populations. The authors concluded that there is substantial variation in the strength and direction of selection over time, but acknowledged that sampling error would result in estimates of selection that were more variable than the true values. We reanalyze their dataset using techniques that account for the necessary effect of sampling error to inflate apparent levels of variation and show that directional selection is remarkably constant over time, both in magnitude and direction. Thus we cannot claim that the available data support the existence of substantial temporal heterogeneity in selection. Nonetheless, we conject that temporal variation in selection could be important, but that there are good reasons why it may not appear in the available data. These new analyses highlight the importance of applying techniques that estimate parameters of the distribution of selection, rather than parameters of the distribution of estimated selection (which will reflect both sampling error and "real" variation in selection); indeed, despite availability of methods for the former, focus on the latter has been common in synthetic reviews of the aspects of selection in nature, and can lead to serious misinterpretations. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  18. 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.

  19. Models of microbiome evolution incorporating host and microbial selection.

    Science.gov (United States)

    Zeng, Qinglong; Wu, Steven; Sukumaran, Jeet; Rodrigo, Allen

    2017-09-25

    Numerous empirical studies suggest that hosts and microbes exert reciprocal selective effects on their ecological partners. Nonetheless, we still lack an explicit framework to model the dynamics of both hosts and microbes under selection. In a previous study, we developed an agent-based forward-time computational framework to simulate the neutral evolution of host-associated microbial communities in a constant-sized, unstructured population of hosts. These neutral models allowed offspring to sample microbes randomly from parents and/or from the environment. Additionally, the environmental pool of available microbes was constituted by fixed and persistent microbial OTUs and by contributions from host individuals in the preceding generation. In this paper, we extend our neutral models to allow selection to operate on both hosts and microbes. We do this by constructing a phenome for each microbial OTU consisting of a sample of traits that influence host and microbial fitnesses independently. Microbial traits can influence the fitness of hosts ("host selection") and the fitness of microbes ("trait-mediated microbial selection"). Additionally, the fitness effects of traits on microbes can be modified by their hosts ("host-mediated microbial selection"). We simulate the effects of these three types of selection, individually or in combination, on microbiome diversities and the fitnesses of hosts and microbes over several thousand generations of hosts. We show that microbiome diversity is strongly influenced by selection acting on microbes. Selection acting on hosts only influences microbiome diversity when there is near-complete direct or indirect parental contribution to the microbiomes of offspring. Unsurprisingly, microbial fitness increases under microbial selection. Interestingly, when host selection operates, host fitness only increases under two conditions: (1) when there is a strong parental contribution to microbial communities or (2) in the absence of a strong

  20. Synthesis and characterization of ion imprinted polymeric adsorbents for the selective recognition and removal of arsenic and selenium in wastewater samples

    Directory of Open Access Journals (Sweden)

    Lihle D. Mafu

    2016-09-01

    Full Text Available Arsenic (As and selenium (Se ion imprinted polymers, As-IIPs and Se-IIPs, were synthesized via bulk polymerization. The prepared materials were then characterized using Fourier Transform Infrared (FT-IR, scanning electron microscopy (SEM and thermogravimetric analysis (TGA. These characterization methods confirmed the difference between IIPs and non-imprinted polymers (NIP. From the adsorption studies done IIPs did not only show better adsorption than NIPs but also better selectivities as well. As adsorption using As-IIPs (AsAsIIPs reached a maximum of 482 μg g−1 whilst Se adsorption using Se-IIPs (SeSeIIPs reached a maximum of 447 μg g−1 after optimization of the sample pH, adsorption time and sample temperature. However these adsorption capacities were increased to 568 μg g−1 and 530 μg g−1 for As and Se respectively when column experiments were done at the same sample temperature and pH. Against Pb, Cd and Hg, As-IIPs and Se-IIPs showed selectivity towards As and Se, respectively.

  1. SpArcFiRe: morphological selection effects due to reduced visibility of tightly winding arms in distant spiral galaxies

    Science.gov (United States)

    Peng, Tianrui Rae; Edward English, John; Silva, Pedro; Davis, Darren R.; Hayes, Wayne B.

    2018-03-01

    The Galaxy Zoo project has provided a plethora of valuable morphological data on a large number of galaxies from various surveys, and their team have identified and/or corrected for many biases. Here we study a new bias related to spiral arm pitch angles, which first requires selecting a sample of spiral galaxies that show observable structure. One obvious way is to select galaxies using a threshold in spirality, which we define as the fraction of Galaxy Zoo humans who have reported seeing spiral structure. Using such a threshold, we use the automated tool SpArcFiRe (SPiral ARC FInder and REporter) to measure spiral arm pitch angles. We observe that the mean pitch angle of spiral arms increases linearly with redshift for 0.05 data to provide a spirality for each artificially degraded image. We find that SpARcFiRe's ability to accurately measure pitch angles decreases as the image degrades, but that spirality decreases more quickly in galaxies with tightly wound arms, leading to the selection effect. This new bias means one must be careful in selecting a sample on which to measure spiral structure. Finally, we also include a sensitivity analysis of SpArcFiRe's internal parameters.

  2. Polymeric membrane sensors based on Cd(II) Schiff base complexes for selective iodide determination in environmental and medicinal samples.

    Science.gov (United States)

    Singh, Ashok Kumar; Mehtab, Sameena

    2008-01-15

    The two cadmium chelates of schiff bases, N,N'-bis(salicylidene)-1,4-diaminobutane, (Cd-S(1)) and N,N'-bis(salicylidene)-3,4-diaminotoluene (Cd-S(2)), have been synthesized and explored as ionophores for preparing PVC-based membrane sensors selective to iodide(I) ion. Potentiometric investigations indicate high affinity of these receptors for iodide ion. Polyvinyl chloride (PVC)-based membranes of Cd-S(1) and Cd-S(2) using as hexadecyltrimethylammonium bromide (HTAB) cation discriminator and o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), acetophenone (AP) and tributylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as iodide-selective sensors. The best performance was shown by the membrane of composition (w/w) of (Cd-S(1)) (7%):PVC (31%):DBP (60%):HTAB (2%). The sensor works well over a wide concentration range 5.3x10(-7) to 1.0x10(-2)M with Nernstian compliance (59.2mVdecade(-1) of activity) within pH range 2.5-9.0 with a response time of 11s and showed good selectivity for iodide ion over a number of anions. The sensor exhibits adequate life (3 months) with good reproducibility (S.D.+/-0.24mV) and could be used successfully for the determination of iodide content in environmental water samples and mouth wash samples.

  3. THE EFFECT OF SELECTED PHYSICAL AND CHEMICAL PARAMETERS ON MICROBIOLOGICAL STATUS OF THE VISTULA RIVER NEAR WARSAW

    OpenAIRE

    Janusz Augustynowicz; Mariusz Nierebiński; Małgorzata Zawada; Russel Russel

    2016-01-01

    The types of organisms present in water reservoirs depend on water purity and biochemical processes that occur. Therefore, one of the methods of water quality assessment is to determine its condition by determining the biological indicators, including microbiological parameters. The aim of the experiment presented in this paper was to investigate the effects of selected physical and chemical parameters of water samples from the Vistula River on the microbiological status of water. The experim...

  4. 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.

  5. The effectiveness of group selection theory on the quality of drug addicted life

    Directory of Open Access Journals (Sweden)

    M Sodani

    2017-01-01

    Full Text Available Backgrounds and aim: Increase in addiction in the community and the plight of its people demand for improving the problems of addicts, indicate a need for individuals to interventions and training expertise. The aim of this study was to investigate the effectiveness of group selection theory on the quality of drug addicted life.  .  Methods: This study is an quasi-experimental design with pretest-posttest and follow up with the control group. The study population included: all addicted people who referred to ahvaz addiction treatment center in 2015. 50 addicts were selected by using of  available sampling and randomly divided into  two experimental group (number=25 and control group (number=25. The participants were completed the quality of life inventory in three stages (pre-test, post-test and follow-up after 60 days. The experimental group was received group training of the concepts of selection theory of 10 sessions of 90 minutes per week.Statistical data were analyzed  using of covariance(ANCOVA analysis. Results: Group training theory led to a significant difference among pretest, posttest, and follow-up of quality of addicted people life (p <0.001. In this case, the post-test and follow-up, after controlling of pre-test score, the experimental group compared to the control group higher quality of life was reported. Conclusion: Group training of selected theory about the role of choosing a behavior, five senses  the importance of self control, the role of effective behavior, the way of need fulfilment, responsibility, self worth, Quality world, seven destructive behavior, seven caring behavior, faiure identification and success identification can result in increasing the quality of life for addicted people.

  6. Effectiveness of Cognitive-Behavioral Therapy on Premenstrual Syndrome Through Compliance to Treatment in an Iranian Sample

    Directory of Open Access Journals (Sweden)

    Setareh Babajani

    2017-06-01

    Full Text Available Background This study aims to investigate the effectiveness of cognitive-behavioral therapy on reducing the symptoms of premenstrual syndrome based on the moderator variable of therapy compliance in an Iranian sample. Methods This was a semi-experimental study, in which 56 patients with premenstrual syndrome disorder were selected using the accessible sampling method. They were all the female patients who had been referred to the gynecologic and psychiatric centers in Isfahan city, and were randomly assigned into two experimental and control groups, each one comprising 28 patients. The experimental group received 10 sessions of cognitive-behavioral therapy. The patients were tested before and after intervention using the screening questionnaires of premenstrual syndrome symptoms. Additionally, subjects in both experimental and control groups were divided into two groups based on the rate of their therapy compliance (from high to low or noncompliant. Data was Analyzed using of covariance and Cohen’s size effect with SPSS-22. Results The results showed that the effectiveness of cognitive-behavioral therapy on reducing the symptoms of premenstrual syndrome was statistically significant. Moreover, research findings have shown that the therapy was more effective on the compliant group. Conclusion According to the results, cognitive behavior therapy can be suggested as an effective therapeutic approach in reducing the symptoms of premenstrual syndrome, especially for the patients who are complient.

  7. Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part II. Application to sediment and sludge samples in Austria

    International Nuclear Information System (INIS)

    Martinez-Carballo, Elena; Gonzalez-Barreiro, Carmen; Sitka, Andrea; Kreuzinger, Norbert; Scharf, Sigrid; Gans, Oliver

    2007-01-01

    Soxhlet extraction and high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry detection (MS/MS) was used for the determination of selected quaternary ammonium compounds (QACs) in solid samples. The method was applied for the determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds in sediment and sludge samples in Austria. The overall method quantification limits range from 0.6 to 3 μg/kg for sediments and from 2 to 5 μg/kg for sewage sludges. Mean recoveries between 67% and 95% are achieved. In general sediments were especially contaminated by C12 chain benzalkonium chloride (BAC-C12) as well as by the long C-chain dialkyldimethylammonium chloride (DDAC-C18) with a maximum concentration of 3.6 mg/kg and 2.1 mg/kg, respectively. Maxima of 27 mg/kg for DDAC-C10, 25 mg/kg for BAC-C12 and 23 mg/kg for BAC-C14 were determined for sludge samples. The sums of the 12 selected target compounds range from 22 mg/kg to 103 mg/kg in the sludge samples. - The presence of quaternary ammonium surfactants in sediment and sludge samples is reported for the first time in Austria

  8. Highly selective solid phase extraction and preconcentration of Azathioprine with nano-sized imprinted polymer based on multivariate optimization and its trace determination in biological and pharmaceutical samples

    Energy Technology Data Exchange (ETDEWEB)

    Davarani, Saied Saeed Hosseiny, E-mail: ss-hosseiny@cc.sbu.ac.ir [Faculty of Chemistry, Shahid Beheshti University, G. C., P.O. Box 19839-4716, Tehran (Iran, Islamic Republic of); Rezayati zad, Zeinab [Faculty of Chemistry, Shahid Beheshti University, G. C., P.O. Box 19839-4716, Tehran (Iran, Islamic Republic of); Taheri, Ali Reza; Rahmatian, Nasrin [Islamic Azad University, Ilam Branch, Ilam (Iran, Islamic Republic of)

    2017-02-01

    In this research, for first time selective separation and determination of Azathioprine is demonstrated using molecularly imprinted polymer as the solid-phase extraction adsorbent, measured by spectrophotometry at λ{sub max} 286 nm. The selective molecularly imprinted polymer was produced using Azathioprine and methacrylic acid as a template molecule and monomer, respectively. A molecularly imprinted solid-phase extraction procedure was performed in column for the analyte from pharmaceutical and serum samples. The synthesized polymers were characterized by infrared spectroscopy (IR), field emission scanning electron microscopy (FESEM). In order to investigate the effect of independent variables on the extraction efficiency, the response surface methodology (RSM) based on Box–Behnken design (BBD) was employed. The analytical parameters such as precision, accuracy and linear working range were also determined in optimal experimental conditions and the proposed method was applied to analysis of Azathioprine. The linear dynamic range and limits of detection were 2.5–0.01 and 0.008 mg L{sup ‐1} respectively. The recoveries for analyte were higher than 95% and relative standard deviation values were found to be in the range of 0.83–4.15%. This method was successfully applied for the determination of Azathioprine in biological and pharmaceutical samples. - Graphical abstract: A new-nano sized imprinted polymer was synthesized and applied as sorbent in SPE in order to selective recognition, preconcentration, and determination of Azathioprine with the response surface methodology based on Box–Behnken design and was successfully investigated for the clean-up of human blood serum and pharmaceutical samples. - Highlights: • The nanosized-imprinted polymer has been synthesized by precipitation polymerization technique. • A molecularly imprinted solid-phase extraction procedure was performed for determination of Azathioprine. • The Azathioprine

  9. Highly selective solid phase extraction and preconcentration of Azathioprine with nano-sized imprinted polymer based on multivariate optimization and its trace determination in biological and pharmaceutical samples

    International Nuclear Information System (INIS)

    Davarani, Saied Saeed Hosseiny; Rezayati zad, Zeinab; Taheri, Ali Reza; Rahmatian, Nasrin

    2017-01-01

    In this research, for first time selective separation and determination of Azathioprine is demonstrated using molecularly imprinted polymer as the solid-phase extraction adsorbent, measured by spectrophotometry at λ max 286 nm. The selective molecularly imprinted polymer was produced using Azathioprine and methacrylic acid as a template molecule and monomer, respectively. A molecularly imprinted solid-phase extraction procedure was performed in column for the analyte from pharmaceutical and serum samples. The synthesized polymers were characterized by infrared spectroscopy (IR), field emission scanning electron microscopy (FESEM). In order to investigate the effect of independent variables on the extraction efficiency, the response surface methodology (RSM) based on Box–Behnken design (BBD) was employed. The analytical parameters such as precision, accuracy and linear working range were also determined in optimal experimental conditions and the proposed method was applied to analysis of Azathioprine. The linear dynamic range and limits of detection were 2.5–0.01 and 0.008 mg L ‐1 respectively. The recoveries for analyte were higher than 95% and relative standard deviation values were found to be in the range of 0.83–4.15%. This method was successfully applied for the determination of Azathioprine in biological and pharmaceutical samples. - Graphical abstract: A new-nano sized imprinted polymer was synthesized and applied as sorbent in SPE in order to selective recognition, preconcentration, and determination of Azathioprine with the response surface methodology based on Box–Behnken design and was successfully investigated for the clean-up of human blood serum and pharmaceutical samples. - Highlights: • The nanosized-imprinted polymer has been synthesized by precipitation polymerization technique. • A molecularly imprinted solid-phase extraction procedure was performed for determination of Azathioprine. • The Azathioprine-molecular imprinting

  10. Method of Observation and their Effects in the Selection of Potential Football Goalkeepers

    Directory of Open Access Journals (Sweden)

    Zerf Mohammed

    2017-11-01

    Full Text Available The criteria and methods for goalkeeper selection are more strict and complex than those of field players. Founded on its principles, the present study tried to examine the strengths and weaknesses of selection process practised by Algerian coaches. Interpret by Algerian scientists in their subjectivity in evaluating the amount of body fat and its effect on physical performance. Seen it's built with the naked eye. Confirmed by FIFA in two categories normal vs overweight, they should work harder under these conditions. For this proposal, eight teams from the leagues of Oran, Algeria Championship second division were involved in the study. Their goalkeepers were classified into the following groups: total (GK = 28, Main goalkeeper (MG = 14 and replacement goalkeeper (RG = 14. Tested at the end of the outward phase by penalty kicks test, ‘T’ Drill Test, Ruler Drop Test (TR and anthropometric parameters (BH, BMI, BFP, BW. Backed on the applied statistical where our total sample is categorised in overweight, as well as no statistically significant differences between the two groups in all the comparisons practised. Our results confirm the weaknesses of traditional methods. Admit by similar studies in their subjective in evaluating the amount of body fat and its effect on physical performance correlate to anthropometric measurement.

  11. Effectiveness of a Selective Advising Program in Reducing the Degree of Compulsive Buying Behavior among Umm Al-Qura Female Students

    Science.gov (United States)

    Basyouni, Sawzan S.

    2018-01-01

    The present study is an attempt to investigate the effectiveness of a selective advising program in reducing the degree of Compulsive Buying Behavior among female students, Faculty of Education at Umm al-Qura University. The sample consisted of (200) female students to verify the validity and reliability of the tool. The quasi-experimental method…

  12. Selection of Photon Gluon Fusion Events in DIS

    International Nuclear Information System (INIS)

    Kowalik, K.; Rondio, E.; Sulej, R.; Zaremba, K.

    2001-01-01

    A selection of the Photon Gluon Fusion (PGF) process with light quarks for deep inelastic scattering events is presented. This process is directly sensitive to gluon polarization and our goal is to find out the most effective selection on a sample of events simulated for the SMC experiment. We compare two general multi-class classification methods - Bayes method and neural network with a conventional selection procedure. The neural network algorithm presented here is a modification of method belonging to the family of directional minimization algorithms. This method is convenient and effective for photon gluon fusion selection and determination of gluon polarization. Finally we present the estimation for precision of gluon polarization for neural network method. (author)

  13. Rapid determination of trace level copper in tea infusion samples by solid contact ion selective electrode

    Directory of Open Access Journals (Sweden)

    Aysenur Birinci

    2016-07-01

    Full Text Available A new solid contact copper selective electrode with a poly (vinyl chloride (PVC membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds and near-Nernstian response to Cu2+ activity from 10−1 to 10−6 mol/L at the pH range of 4.0–6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS.

  14. Evaluation of sampling strategies to estimate crown biomass

    Directory of Open Access Journals (Sweden)

    Krishna P Poudel

    2015-01-01

    Full Text Available Background Depending on tree and site characteristics crown biomass accounts for a significant portion of the total aboveground biomass in the tree. Crown biomass estimation is useful for different purposes including evaluating the economic feasibility of crown utilization for energy production or forest products, fuel load assessments and fire management strategies, and wildfire modeling. However, crown biomass is difficult to predict because of the variability within and among species and sites. Thus the allometric equations used for predicting crown biomass should be based on data collected with precise and unbiased sampling strategies. In this study, we evaluate the performance different sampling strategies to estimate crown biomass and to evaluate the effect of sample size in estimating crown biomass. Methods Using data collected from 20 destructively sampled trees, we evaluated 11 different sampling strategies using six evaluation statistics: bias, relative bias, root mean square error (RMSE, relative RMSE, amount of biomass sampled, and relative biomass sampled. We also evaluated the performance of the selected sampling strategies when different numbers of branches (3, 6, 9, and 12 are selected from each tree. Tree specific log linear model with branch diameter and branch length as covariates was used to obtain individual branch biomass. Results Compared to all other methods stratified sampling with probability proportional to size estimation technique produced better results when three or six branches per tree were sampled. However, the systematic sampling with ratio estimation technique was the best when at least nine branches per tree were sampled. Under the stratified sampling strategy, selecting unequal number of branches per stratum produced approximately similar results to simple random sampling, but it further decreased RMSE when information on branch diameter is used in the design and estimation phases. Conclusions Use of

  15. Supernovae - A new selection effect. [statistical distribution in and radial distance from center of parent galaxy

    Science.gov (United States)

    Shaw, R. L.

    1979-01-01

    A sample of 228 supernovae that occurred in galaxies with known redshifts is used to show that the mean projected linear supernova distance from the center of the parent galaxy increases with increasing redshift. This effect is interpreted as an observational bias: the discovery rate of supernovae is reduced in the inner parts of distant, poorly resolved galaxies. Even under the optimistic assumption that no selection effects work in galaxies closer than 33 Mpc, about 50% of all supernovae are lost in the inner regions of galaxies beyond 150 Mpc. This observational bias must be taken into account in the derivation of statistical properties of supernovae.

  16. A Heckman Selection- t Model

    KAUST Repository

    Marchenko, Yulia V.

    2012-03-01

    Sample selection arises often in practice as a result of the partial observability of the outcome of interest in a study. In the presence of sample selection, the observed data do not represent a random sample from the population, even after controlling for explanatory variables. That is, data are missing not at random. Thus, standard analysis using only complete cases will lead to biased results. Heckman introduced a sample selection model to analyze such data and proposed a full maximum likelihood estimation method under the assumption of normality. The method was criticized in the literature because of its sensitivity to the normality assumption. In practice, data, such as income or expenditure data, often violate the normality assumption because of heavier tails. We first establish a new link between sample selection models and recently studied families of extended skew-elliptical distributions. Then, this allows us to introduce a selection-t (SLt) model, which models the error distribution using a Student\\'s t distribution. We study its properties and investigate the finite-sample performance of the maximum likelihood estimators for this model. We compare the performance of the SLt model to the conventional Heckman selection-normal (SLN) model and apply it to analyze ambulatory expenditures. Unlike the SLNmodel, our analysis using the SLt model provides statistical evidence for the existence of sample selection bias in these data. We also investigate the performance of the test for sample selection bias based on the SLt model and compare it with the performances of several tests used with the SLN model. Our findings indicate that the latter tests can be misleading in the presence of heavy-tailed data. © 2012 American Statistical Association.

  17. The effect of morphometric atlas selection on multi-atlas-based automatic brachial plexus segmentation

    International Nuclear Information System (INIS)

    Van de Velde, Joris; Wouters, Johan; Vercauteren, Tom; De Gersem, Werner; Achten, Eric; De Neve, Wilfried; Van Hoof, Tom

    2015-01-01

    The present study aimed to measure the effect of a morphometric atlas selection strategy on the accuracy of multi-atlas-based BP autosegmentation using the commercially available software package ADMIRE® and to determine the optimal number of selected atlases to use. Autosegmentation accuracy was measured by comparing all generated automatic BP segmentations with anatomically validated gold standard segmentations that were developed using cadavers. Twelve cadaver computed tomography (CT) atlases were included in the study. One atlas was selected as a patient in ADMIRE®, and multi-atlas-based BP autosegmentation was first performed with a group of morphometrically preselected atlases. In this group, the atlases were selected on the basis of similarity in the shoulder protraction position with the patient. The number of selected atlases used started at two and increased up to eight. Subsequently, a group of randomly chosen, non-selected atlases were taken. In this second group, every possible combination of 2 to 8 random atlases was used for multi-atlas-based BP autosegmentation. For both groups, the average Dice similarity coefficient (DSC), Jaccard index (JI) and Inclusion index (INI) were calculated, measuring the similarity of the generated automatic BP segmentations and the gold standard segmentation. Similarity indices of both groups were compared using an independent sample t-test, and the optimal number of selected atlases was investigated using an equivalence trial. For each number of atlases, average similarity indices of the morphometrically selected atlas group were significantly higher than the random group (p < 0,05). In this study, the highest similarity indices were achieved using multi-atlas autosegmentation with 6 selected atlases (average DSC = 0,598; average JI = 0,434; average INI = 0,733). Morphometric atlas selection on the basis of the protraction position of the patient significantly improves multi-atlas-based BP autosegmentation accuracy

  18. Effects of smoking history on selective attention in schizophrenia.

    Science.gov (United States)

    Hahn, Constanze; Hahn, Eric; Dettling, Michael; Güntürkün, Onur; Ta, Thi Minh Tam; Neuhaus, Andres H

    2012-03-01

    Smoking prevalence is highly elevated in schizophrenia compared to the general population and to other psychiatric populations. Evidence suggests that smoking may lead to improvements of schizophrenia-associated attention deficits; however, large-scale studies on this important issue are scarce. We examined whether sustained, selective, and executive attention processes are differentially modulated by long-term nicotine consumption in 104 schizophrenia patients and 104 carefully matched healthy controls. A significant interaction of 'smoking status' × 'diagnostic group' was obtained for the domain of selective attention. Smoking was significantly associated with a detrimental conflict effect in controls, while the opposite effect was revealed for schizophrenia patients. Likewise, a positive correlation between a cumulative measure of nicotine consumption and conflict effect in controls and a negative correlation in patients were found. These results provide evidence for specific directional effects of smoking on conflict processing that critically dissociate with diagnosis. The data supports the self-medication hypothesis of smoking in schizophrenia and suggests selective attention as a specific cognitive domain targeted by nicotine consumption. A potential mechanistic model explaining these findings is discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Effectiveness of Selected Communication Media on Tourism ...

    African Journals Online (AJOL)

    waterfalls, historical relics, captivating beaches, rock out-crops, rolling lulls coupled with hospitable and culturally active people that are capable of making tourism a delight in Nigeria. The study therefore assessed the effectiveness of selected communication media on awareness creation towards tourism for rural ...

  20. elative age effect in the selection process of handball players of the regional selection teams

    Directory of Open Access Journals (Sweden)

    Manuel Gómez López

    2017-06-01

    Full Text Available This study aimed to analyze the effect of age on adolescent handball players of the regional selection teams. To do this, data of sex and date of birth of 84 youth players from different regional selection teams in the 2015-2016 season were analyzed, performing comparisons and differences being studied by χ2 and Z tests and the Bonferroni method. The analysis of results by quarter and half of birth revealed no statistically significant differences in gender and category. It seems to confirm that there is not relative age effect in the analyzed Teams. Whereupon, seems to confirm that in handball base, all young people participate, regardless of the degree of maturity submit.

  1. Effect of Integrated Yoga Module on Selected Psychological Variables among Women with Anxiety Problem.

    Science.gov (United States)

    Parthasarathy, S; Jaiganesh, K; Duraisamy

    2014-01-01

    The implementation of yogic practices has proven benefits in both organic and psychological diseases. Forty-five women with anxiety selected by a random sampling method were divided into three groups. Experimental group I was subjected to asanas, relaxation and pranayama while Experimental group II was subjected to an integrated yoga module. The control group did not receive any intervention. Anxiety was measured by Taylor's Manifest Anxiety Scale before and after treatment. Frustration was measured through Reaction to Frustration Scale. All data were spread in an Excel sheet to be analysed with SPSS 16 software using analysis of covariance (ANCOVA). Selected yoga and asanas decreased anxiety and frustration scores but treatment with an integrated yoga module resulted in significant reduction of anxiety and frustration. To conclude, the practice of asanas and yoga decreased anxiety in women, and yoga as an integrated module significantly improved anxiety scores in young women with proven anxiety without any ill effects.

  2. The effect of DNA degradation bias in passive sampling devices on metabarcoding studies of arthropod communities and their associated microbiota.

    Science.gov (United States)

    Krehenwinkel, Henrik; Fong, Marisa; Kennedy, Susan; Huang, Edward Greg; Noriyuki, Suzuki; Cayetano, Luis; Gillespie, Rosemary

    2018-01-01

    PCR amplification bias is a well-known problem in metagenomic analysis of arthropod communities. In contrast, variation of DNA degradation rates is a largely neglected source of bias. Differential degradation of DNA molecules could cause underrepresentation of taxa in a community sequencing sample. Arthropods are often collected by passive sampling devices, like malaise traps. Specimens in such a trap are exposed to varying periods of suboptimal storage and possibly different rates of DNA degradation. Degradation bias could thus be a significant issue, skewing diversity estimates. Here, we estimate the effect of differential DNA degradation on the recovery of community diversity of Hawaiian arthropods and their associated microbiota. We use a simple DNA size selection protocol to test for degradation bias in mock communities, as well as passively collected samples from actual Malaise traps. We compare the effect of DNA degradation to that of varying PCR conditions, including primer choice, annealing temperature and cycle number. Our results show that DNA degradation does indeed bias community analyses. However, the effect of this bias is of minor importance compared to that induced by changes in PCR conditions. Analyses of the macro and microbiome from passively collected arthropod samples are thus well worth pursuing.

  3. A bayesian hierarchical model for classification with selection of functional predictors.

    Science.gov (United States)

    Zhu, Hongxiao; Vannucci, Marina; Cox, Dennis D

    2010-06-01

    In functional data classification, functional observations are often contaminated by various systematic effects, such as random batch effects caused by device artifacts, or fixed effects caused by sample-related factors. These effects may lead to classification bias and thus should not be neglected. Another issue of concern is the selection of functions when predictors consist of multiple functions, some of which may be redundant. The above issues arise in a real data application where we use fluorescence spectroscopy to detect cervical precancer. In this article, we propose a Bayesian hierarchical model that takes into account random batch effects and selects effective functions among multiple functional predictors. Fixed effects or predictors in nonfunctional form are also included in the model. The dimension of the functional data is reduced through orthonormal basis expansion or functional principal components. For posterior sampling, we use a hybrid Metropolis-Hastings/Gibbs sampler, which suffers slow mixing. An evolutionary Monte Carlo algorithm is applied to improve the mixing. Simulation and real data application show that the proposed model provides accurate selection of functional predictors as well as good classification.

  4. 40 CFR 761.353 - Second level of sample selection.

    Science.gov (United States)

    2010-07-01

    .... At the chemical extraction and analysis laboratory, pour the 19-liter subsample onto a plastic sheet..., AND USE PROHIBITIONS Sampling Non-Liquid, Non-Metal PCB Bulk Product Waste for Purposes of Characterization for PCB Disposal in Accordance With § 761.62, and Sampling PCB Remediation Waste Destined for Off...

  5. Reproducibility of NMR analysis of urine samples: impact of sample preparation, storage conditions, and animal health status.

    Science.gov (United States)

    Schreier, Christina; Kremer, Werner; Huber, Fritz; Neumann, Sindy; Pagel, Philipp; Lienemann, Kai; Pestel, Sabine

    2013-01-01

    Spectroscopic analysis of urine samples from laboratory animals can be used to predict the efficacy and side effects of drugs. This employs methods combining (1)H NMR spectroscopy with quantification of biomarkers or with multivariate data analysis. The most critical steps in data evaluation are analytical reproducibility of NMR data (collection, storage, and processing) and the health status of the animals, which may influence urine pH and osmolarity. We treated rats with a solvent, a diuretic, or a nephrotoxicant and collected urine samples. Samples were titrated to pH 3 to 9, or salt concentrations increased up to 20-fold. The effects of storage conditions and freeze-thaw cycles were monitored. Selected metabolites and multivariate data analysis were evaluated after (1)H NMR spectroscopy. We showed that variation of pH from 3 to 9 and increases in osmolarity up to 6-fold had no effect on the quantification of the metabolites or on multivariate data analysis. Storage led to changes after 14 days at 4°C or after 12 months at -20°C, independent of sample composition. Multiple freeze-thaw cycles did not affect data analysis. Reproducibility of NMR measurements is not dependent on sample composition under physiological or pathological conditions.

  6. Reproducibility of NMR Analysis of Urine Samples: Impact of Sample Preparation, Storage Conditions, and Animal Health Status

    Directory of Open Access Journals (Sweden)

    Christina Schreier

    2013-01-01

    Full Text Available Introduction. Spectroscopic analysis of urine samples from laboratory animals can be used to predict the efficacy and side effects of drugs. This employs methods combining 1H NMR spectroscopy with quantification of biomarkers or with multivariate data analysis. The most critical steps in data evaluation are analytical reproducibility of NMR data (collection, storage, and processing and the health status of the animals, which may influence urine pH and osmolarity. Methods. We treated rats with a solvent, a diuretic, or a nephrotoxicant and collected urine samples. Samples were titrated to pH 3 to 9, or salt concentrations increased up to 20-fold. The effects of storage conditions and freeze-thaw cycles were monitored. Selected metabolites and multivariate data analysis were evaluated after 1H NMR spectroscopy. Results. We showed that variation of pH from 3 to 9 and increases in osmolarity up to 6-fold had no effect on the quantification of the metabolites or on multivariate data analysis. Storage led to changes after 14 days at 4°C or after 12 months at −20°C, independent of sample composition. Multiple freeze-thaw cycles did not affect data analysis. Conclusion. Reproducibility of NMR measurements is not dependent on sample composition under physiological or pathological conditions.

  7. Sampling and analysis plan for the consolidated sludge samples from the canisters and floor of the 105-K East basin

    International Nuclear Information System (INIS)

    BAKER, R.B.

    1999-01-01

    This Sampling and Analysis Plan (SAP) provides direction for sampling of fuel canister and floor Sludge from the K East Basin to complete the inventory of samples needed for Sludge treatment process testing. Sample volumes and sources consider recent reviews made by the Sludge treatment subproject. The representative samples will be characterized to the extent needed for the material to be used effectively for testing. Sampling equipment used allows drawing of large volume sludge samples and consolidation of sample material from a number of basin locations into one container. Once filled, the containers will be placed in a cask and transported to Hanford laboratories for recovery and evaluation. Included in the present SAP are the logic for sample location selection, laboratory analysis procedures required, and reporting needed to meet the Data Quality Objectives (DQOs) for this initiative

  8. Suitability of selected free-gas and dissolved-gas sampling containers for carbon isotopic analysis.

    Science.gov (United States)

    Eby, P; Gibson, J J; Yi, Y

    2015-07-15

    Storage trials were conducted for 2 to 3 months using a hydrocarbon and carbon dioxide gas mixture with known carbon isotopic composition to simulate typical hold times for gas samples prior to isotopic analysis. A range of containers (both pierced and unpierced) was periodically sampled to test for δ(13)C isotopic fractionation. Seventeen containers were tested for free-gas storage (20°C, 1 atm pressure) and 7 containers were tested for dissolved-gas storage, the latter prepared by bubbling free gas through tap water until saturated (20°C, 1 atm) and then preserved to avoid biological activity by acidifying to pH 2 with phosphoric acid and stored in the dark at 5°C. Samples were extracted using valves or by piercing septa, and then introduced into an isotope ratio mass spectrometer for compound-specific δ(13)C measurements. For free gas, stainless steel canisters and crimp-top glass serum bottles with butyl septa were most effective at preventing isotopic fractionation (pierced and unpierced), whereas silicone and PTFE-butyl septa allowed significant isotopic fractionation. FlexFoil and Tedlar bags were found to be effective only for storage of up to 1 month. For dissolved gas, crimp-top glass serum bottles with butyl septa were again effective, whereas silicone and PTFE-butyl were not. FlexFoil bags were reliable for up to 2 months. Our results suggest a range of preferred containers as well as several that did not perform very well for isotopic analysis. Overall, the results help establish better QA/QC procedures to avoid isotopic fractionation when storing environmental gas samples. Recommended containers for air transportation include steel canisters and glass serum bottles with butyl septa (pierced and unpierced). Copyright © 2015 John Wiley & Sons, Ltd.

  9. [Effect sizes, statistical power and sample sizes in "the Japanese Journal of Psychology"].

    Science.gov (United States)

    Suzukawa, Yumi; Toyoda, Hideki

    2012-04-01

    This study analyzed the statistical power of research studies published in the "Japanese Journal of Psychology" in 2008 and 2009. Sample effect sizes and sample statistical powers were calculated for each statistical test and analyzed with respect to the analytical methods and the fields of the studies. The results show that in the fields like perception, cognition or learning, the effect sizes were relatively large, although the sample sizes were small. At the same time, because of the small sample sizes, some meaningful effects could not be detected. In the other fields, because of the large sample sizes, meaningless effects could be detected. This implies that researchers who could not get large enough effect sizes would use larger samples to obtain significant results.

  10. Untold stories: biases and selection effects in research with victims of trafficking for sexual exploitation.

    Science.gov (United States)

    Brunovskis, Anette; Surtees, Rebecca

    2010-01-01

    Recent discussions of trafficking research have included calls for more innovative studies and new methodologies in order to move beyond the current trafficking narrative, which is often based on unrepresentative samples and overly simplified images. While new methods can potentially play a role in expanding the knowledge base on trafficking, this article argues that the solution is not entirely about applying new methods, but as much about using current methods to greater effect and with careful attention to their limitations and ethical constraints. Drawing on the authors' experience in researching trafficking issues in a number of projects over the past decade, the article outlines and exemplifies some of the methodological and ethical issues to be considered and accommodated when conducting research with trafficked persons -- including unrepresentative samples; access to respondents; selection biases by "gatekeepers" and self selection by potential respondents. Such considerations should inform not only how research is undertaken but also how this information is read and understood. Moreover, many of these considerations equally apply when considering the application of new methods within this field. The article maintains that a better understanding of how these issues come into play and inform trafficking research will translate into tools for conducting improved research in this field and, by implication, new perspectives on human trafficking.

  11. Effect of selective versus non-selective cyclooxygenase inhibitors on ischemia-reperfusion-induced hepatic injury in rats.

    Science.gov (United States)

    Abdel-Gaber, Seham A; Ibrahim, Mohamed A; Amin, Entesar F; Ibrahim, Salwa A; Mohammed, Rehab K; Abdelrahman, Aly M

    2015-08-01

    Ischemia-reperfusion (IR) injury represents an important pathological process of liver injury during major hepatic surgery. The role of cyclooxygenase (COX) enzymes in the pathogenesis of ischemia-reperfusion (IR)-induced liver injury is not clear. This study investigated the effect of a selective COX-2 inhibitor, celecoxib, versus non-selective, indomethacin, on hepatic IR injury in rats. Hepatic IR was induced in adult male rats. The animals were divided into 4 groups: normal control (sham group), IR non-treated group; IR-indomethacin-treated group; and IR-celecoxib-treated group. Liver injury was evaluated by serum alanine aminotransferase (ALT) and a histopathological examination of liver tissues. Hepatic tissue content of oxidative stress parameters glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase, malondialdehyde (MDA), nitric oxide (NO) and the inflammatory marker, tumor necrosis factor-alpha, (TNF-α) were measured. Moreover, the immunohistochemical detection of endothelial NO synthase (eNOS), inducible NO synthase (iNOS), and caspase-3 in the hepatic tissue was performed. Celecoxib, but not indomethacin, significantly attenuated hepatic IR injury as evidenced by reduction in serum ALT as well as by improvement in the histopathological scoring. Such effect was associated with attenuation in oxidative stress and TNF-α, along with modulation of immunohistochemical expression of eNOS, iNOS and caspase-3 in the hepatic tissue. The present study concluded that selective COX-2 inhibition (but not non-selective), is hepatoprotective against liver IR injury; indicating a differential role of COX-1 versus COX-2. Modulation of iNOS, eNOS and caspase-3 might participate in the protective effect of selective COX-2-inhibitors. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Serial Entrepreneurship, Learning by Doing and Self-selection

    DEFF Research Database (Denmark)

    Rocha, Vera; Carneiro, Anabela; Varum, Celeste

    2015-01-01

    of the person-specific effect, using information on individuals’ past histories in paid employment, confirm that serial entrepreneurs exhibit, on average, a larger person-specific effect than non-serial business owners. Moreover, ignoring serial entrepreneurs’ self-selection overestimates learning by doing......It remains a question whether serial entrepreneurs typically perform better than their novice counterparts owing to learning by doing effects or mostly because they are a selected sample of higher-than-average ability entrepreneurs. This paper tries to unravel these two effects by exploring a novel...... empirical strategy based on continuous time duration models with selection. We use a large longitudinal matched employer-employee dataset that allows us to identify about 220,000 individuals who have left their first entrepreneurial experience, out of which over 35,000 became serial entrepreneurs. We...

  13. Experimental breakdown of selected anodized aluminum samples in dilute plasmas

    Science.gov (United States)

    Grier, Norman T.; Domitz, Stanley

    1992-01-01

    Anodized aluminum samples representative of Space Station Freedom structural material were tested for electrical breakdown under space plasma conditions. In space, this potential arises across the insulating anodized coating when the spacecraft structure is driven to a negative bias relative to the external plasma potential due to plasma-surface interaction phenomena. For anodized materials used in the tests, it was found that breakdown voltage varied from 100 to 2000 volts depending on the sample. The current in the arcs depended on the sample, the capacitor, and the voltage. The level of the arc currents varied from 60 to 1000 amperes. The plasma number density varied from 3 x 10 exp 6 to 10 exp 3 ions per cc. The time between arcs increased as the number density was lowered. Corona testing of anodized samples revealed that samples with higher corona inception voltage had higher arcing inception voltages. From this it is concluded that corona testing may provide a method of screening the samples.

  14. Molecularly imprinted layer-coated silica nanoparticles for selective solid-phase extraction of bisphenol A from chemical cleansing and cosmetics samples

    International Nuclear Information System (INIS)

    Zhu Rong; Zhao Wenhui; Zhai Meijuan; Wei Fangdi; Cai Zheng; Sheng Na; Hu Qin

    2010-01-01

    Highly selective molecularly imprinted layer-coated silica nanoparticles for bisphenol A (BPA) were synthesized by molecular imprinting technique with a sol-gel process on the supporter of silica nanoparticles. The BPA-imprinted silica nanoparticles were characterized by fourier transform infrared spectrometer, transmission electron microscope, dynamic adsorption and static adsorption tests. The equilibrium association constant, K a , and the apparent maximum number of binding sites, Q max , were estimated to be 1.25 x 10 5 mL μmol -1 and 16.4 μmol g -1 , respectively. The BPA-imprinted silica nanoparticles solid-phase extraction (SPE) column had higher selectivity for BPA than the commercial C18-SPE column. The results of the study indicated that the prepared BPA-imprinted silica nanoparticles exhibited high adsorption capacity and selectivity, and offered a fast kinetics for the rebinding of BPA. The BPA-imprinted silica nanoparticles were successfully used in SPE to selectively enrich and determine BPA from shampoo, bath lotion and cosmetic cream samples.

  15. Contributions to sampling statistics

    CERN Document Server

    Conti, Pier; Ranalli, Maria

    2014-01-01

    This book contains a selection of the papers presented at the ITACOSM 2013 Conference, held in Milan in June 2013. ITACOSM is the bi-annual meeting of the Survey Sampling Group S2G of the Italian Statistical Society, intended as an international  forum of scientific discussion on the developments of theory and application of survey sampling methodologies and applications in human and natural sciences. The book gathers research papers carefully selected from both invited and contributed sessions of the conference. The whole book appears to be a relevant contribution to various key aspects of sampling methodology and techniques; it deals with some hot topics in sampling theory, such as calibration, quantile-regression and multiple frame surveys, and with innovative methodologies in important topics of both sampling theory and applications. Contributions cut across current sampling methodologies such as interval estimation for complex samples, randomized responses, bootstrap, weighting, modeling, imputati...

  16. Sample selection and taste correlation in discrete choice transport modelling

    DEFF Research Database (Denmark)

    Mabit, Stefan Lindhard

    2008-01-01

    explain counterintuitive results in value of travel time estimation. However, the results also point at the difficulty of finding suitable instruments for the selection mechanism. Taste heterogeneity is another important aspect of discrete choice modelling. Mixed logit models are designed to capture...... the question for a broader class of models. It is shown that the original result may be somewhat generalised. Another question investigated is whether mode choice operates as a self-selection mechanism in the estimation of the value of travel time. The results show that self-selection can at least partly...... of taste correlation in willingness-to-pay estimation are presented. The first contribution addresses how to incorporate taste correlation in the estimation of the value of travel time for public transport. Given a limited dataset the approach taken is to use theory on the value of travel time as guidance...

  17. Design-based estimators for snowball sampling

    OpenAIRE

    Shafie, Termeh

    2010-01-01

    Snowball sampling, where existing study subjects recruit further subjects from amongtheir acquaintances, is a popular approach when sampling from hidden populations.Since people with many in-links are more likely to be selected, there will be a selectionbias in the samples obtained. In order to eliminate this bias, the sample data must beweighted. However, the exact selection probabilities are unknown for snowball samplesand need to be approximated in an appropriate way. This paper proposes d...

  18. The SDSS-IV MaNGA Sample: Design, Optimization, and Usage Considerations

    Science.gov (United States)

    Wake, David A.; Bundy, Kevin; Diamond-Stanic, Aleksandar M.; Yan, Renbin; Blanton, Michael R.; Bershady, Matthew A.; Sánchez-Gallego, José R.; Drory, Niv; Jones, Amy; Kauffmann, Guinevere; Law, David R.; Li, Cheng; MacDonald, Nicholas; Masters, Karen; Thomas, Daniel; Tinker, Jeremy; Weijmans, Anne-Marie; Brownstein, Joel R.

    2017-09-01

    We describe the sample design for the SDSS-IV MaNGA survey and present the final properties of the main samples along with important considerations for using these samples for science. Our target selection criteria were developed while simultaneously optimizing the size distribution of the MaNGA integral field units (IFUs), the IFU allocation strategy, and the target density to produce a survey defined in terms of maximizing signal-to-noise ratio, spatial resolution, and sample size. Our selection strategy makes use of redshift limits that only depend on I-band absolute magnitude (M I ), or, for a small subset of our sample, M I and color (NUV - I). Such a strategy ensures that all galaxies span the same range in angular size irrespective of luminosity and are therefore covered evenly by the adopted range of IFU sizes. We define three samples: the Primary and Secondary samples are selected to have a flat number density with respect to M I and are targeted to have spectroscopic coverage to 1.5 and 2.5 effective radii (R e ), respectively. The Color-Enhanced supplement increases the number of galaxies in the low-density regions of color-magnitude space by extending the redshift limits of the Primary sample in the appropriate color bins. The samples cover the stellar mass range 5× {10}8≤slant {M}* ≤slant 3× {10}11 {M}⊙ {h}-2 and are sampled at median physical resolutions of 1.37 and 2.5 kpc for the Primary and Secondary samples, respectively. We provide weights that will statistically correct for our luminosity and color-dependent selection function and IFU allocation strategy, thus correcting the observed sample to a volume-limited sample.

  19. Vibrating sample magnetometer 2D and 3D magnetization effects associated with different initial magnetization states

    Directory of Open Access Journals (Sweden)

    Ronald E. Lukins

    2017-05-01

    Full Text Available Differences in VSM magnetization vector rotation associated with various initial magnetization states were demonstrated. Procedures and criteria were developed to select sample orientation and initial magnetization states to allow for the combination of two different 2D measurements runs (with the same field profiles to generate a dataset that can be representative of actual 3D magnetization rotation. Nickel, cast iron, and low moment magnetic tape media were used to demonstrate these effects using hysteresis and remanent magnetization test sequences. These results can be used to generate 2D and 3D magnetic properties to better characterize magnetic phenomena which are inherently three dimensional. Example applications are magnetic tape-head orientation sensitivity, reinterpretation of 3D coercivity and other standard magnetic properties, and multi-dimensional shielding effectiveness.

  20. Effect of magnetic field on selectivity of three-step photoionization

    International Nuclear Information System (INIS)

    Lim, Chang Hwan; Rho, Si Pyo; Ko, Kwang Hoon; Kim, Chul Joong; Izawa, Yasukazu

    2001-01-01

    Effect of magnetic field on selectivity by linearly polarized lasers was analyzed by formulating the density matrix equations. To investigate the effect of magnetic field on the selectivity of AVLIS, we proposed a general Hamiltonian for multilevel atomic system in magnetic field. The population dynamics of magnetic sublevels have been observed by solving the Liouville equation. Mixing between magnetic sublevels was observed in each state during the laser excitations when the magnetic field perpendicular to the quantization axis was applied to the atomic system. The magnetic field dependence on ionization rate of even isotopes was also discussed. In the magnetic field dependence, two ionization peaks were appeared because of the interference between Rabi and Larmor frequency during the ionization process. The permissible intensities of magnetic field were predicted to obtain enough selectivity for the target isotopes of zirconium and gadolinium in the AVLIS process based on the polarization selection rule

  1. Selective reduction of arsenic species by hydride generation - atomic absorption spectrometry. Part 2 - sample storage and arsenic determination in natural waters

    Directory of Open Access Journals (Sweden)

    Quináia Sueli P.

    2001-01-01

    Full Text Available Total arsenic, arsenite, arsinate and dimethylarsinic acid (DMA were selectively determined in natural waters by hydride generation - atomic absorption spectrometry, using sodium tetrahydroborate(III as reductant but in different reduction media. River water samples from the north region of Paraná State, Brazil, were analysed and showed arsenate as the principal arsenical form. Detection limits found for As(III (citrate buffer, As(III + DMA (acetic acid and As(III + As(V (hydrochloric acid were 0.6, 1.1 and 0.5 mg As L-1, respectively. Sample storage on the proper reaction media revealed to be a useful way to preserve the water sample.

  2. Selection of reference genes for tissue/organ samples on day 3 fifth-instar larvae in silkworm, Bombyx mori.

    Science.gov (United States)

    Wang, Genhong; Chen, Yanfei; Zhang, Xiaoying; Bai, Bingchuan; Yan, Hao; Qin, Daoyuan; Xia, Qingyou

    2018-06-01

    The silkworm, Bombyx mori, is one of the world's most economically important insect. Surveying variations in gene expression among multiple tissue/organ samples will provide clues for gene function assignments and will be helpful for identifying genes related to economic traits or specific cellular processes. To ensure their accuracy, commonly used gene expression quantification methods require a set of stable reference genes for data normalization. In this study, 24 candidate reference genes were assessed in 10 tissue/organ samples of day 3 fifth-instar B. mori larvae using geNorm and NormFinder. The results revealed that, using the combination of the expression of BGIBMGA003186 and BGIBMGA008209 was the optimum choice for normalizing the expression data of the B. mori tissue/organ samples. The most stable gene, BGIBMGA003186, is recommended if just one reference gene is used. Moreover, the commonly used reference gene encoding cytoplasmic actin was the least appropriate reference gene of the samples investigated. The reliability of the selected reference genes was further confirmed by evaluating the expression profiles of two cathepsin genes. Our results may be useful for future studies involving the quantification of relative gene expression levels of different tissue/organ samples in B. mori. © 2018 Wiley Periodicals, Inc.

  3. Evaluation of sampling plans for in-service inspection of steam generator tubes

    International Nuclear Information System (INIS)

    Kurtz, R.J.; Heasler, P.G.; Baird, D.B.

    1994-02-01

    This report summarizes the results of three previous studies to evaluate and compare the effectiveness of sampling plans for steam generator tube inspections. An analytical evaluation and Monte Carlo simulation techniques were the methods used to evaluate sampling plan performance. To test the performance of candidate sampling plans under a variety of conditions, ranges of inspection system reliability were considered along with different distributions of tube degradation. Results from the eddy current reliability studies performed with the retired-from-service Surry 2A steam generator were utilized to guide the selection of appropriate probability of detection and flaw sizing models for use in the analysis. Different distributions of tube degradation were selected to span the range of conditions that might exist in operating steam generators. The principal means of evaluating sampling performance was to determine the effectiveness of the sampling plan for detecting and plugging defective tubes. A summary of key results from the eddy current reliability studies is presented. The analytical and Monte Carlo simulation analyses are discussed along with a synopsis of key results and conclusions

  4. Pilot studies for the North American Soil Geochemical Landscapes Project - Site selection, sampling protocols, analytical methods, and quality control protocols

    Science.gov (United States)

    Smith, D.B.; Woodruff, L.G.; O'Leary, R. M.; Cannon, W.F.; Garrett, R.G.; Kilburn, J.E.; Goldhaber, M.B.

    2009-01-01

    In 2004, the US Geological Survey (USGS) and the Geological Survey of Canada sampled and chemically analyzed soils along two transects across Canada and the USA in preparation for a planned soil geochemical survey of North America. This effort was a pilot study to test and refine sampling protocols, analytical methods, quality control protocols, and field logistics for the continental survey. A total of 220 sample sites were selected at approximately 40-km intervals along the two transects. The ideal sampling protocol at each site called for a sample from a depth of 0-5 cm and a composite of each of the O, A, and C horizons. The Ca, Fe, K, Mg, Na, S, Ti, Ag, As, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Ga, In, La, Li, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Sn, Sr, Te, Th, Tl, U, V, W, Y, and Zn by inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry following a near-total digestion in a mixture of HCl, HNO3, HClO4, and HF. Separate methods were used for Hg, Se, total C, and carbonate-C on this same size fraction. Only Ag, In, and Te had a large percentage of concentrations below the detection limit. Quality control (QC) of the analyses was monitored at three levels: the laboratory performing the analysis, the USGS QC officer, and the principal investigator for the study. This level of review resulted in an average of one QC sample for every 20 field samples, which proved to be minimally adequate for such a large-scale survey. Additional QC samples should be added to monitor within-batch quality to the extent that no more than 10 samples are analyzed between a QC sample. Only Cr (77%), Y (82%), and Sb (80%) fell outside the acceptable limits of accuracy (% recovery between 85 and 115%) because of likely residence in mineral phases resistant to the acid digestion. A separate sample of 0-5-cm material was collected at each site for determination of organic compounds. A subset of 73 of these samples was analyzed for a suite of

  5. Re-examination of Advertising Effectiveness in Selected Soft Drink Companies in Lagos State, Nigeria: A Descriptive Analysis

    Directory of Open Access Journals (Sweden)

    Adefulu Adesoga

    2015-06-01

    Full Text Available The paper reexamined the effectiveness of Advertising in Selected Soft Drink Companies in Lagos, Nigeria. The study linked with past researches through its extensive conceptual, theoretical and empirical literature review. The methodology adopted was survey research design. The study population was the staff in marketing positions in the selected companies. Questionnaire was administered on samples from the selected Companies. The weighted means and percentage values of the respondents were used in the analysis and decision making. The findings showed the need for a better understanding of organizational factors that determine the commitment of organizational resources to drive achievement of advertising goals because of its impacts on customers’ awareness and product adoption.. The study concluded that advertising is a potent and veritable tool for achieving marketing goals. The study recommended that firms should identify the best advertising program to achieve its advertising goals. By implication, marketing decision maker should incorporate advertising expenditures in the marketing budget in appreciation of its role.

  6. Factors Effecting Adsorption of 137 Cs in Marine Sediment Samples in Marine Sediment Samples from the Upper Gulf of Thailand

    International Nuclear Information System (INIS)

    Saengkul, C.; Sawangwong, P.; Pakkong, P.

    2014-01-01

    Contamination of 137 Cs in sediment is a far more serious problem than in water because sediment is a main transport factor of 137 Cs to the aquatic environmental. Most of 137 Cs in water could be accumulated in sediment which has direct effect to benthos. This study focused on factors effecting the adsorption of 137Cs in marine sediment samples collected from four different estuary sites to assess the transfer direction of 137 Cs from water to sediment that the study method by treat 137 Cs into seawater and mixed with different sediment samples for 4 days. The result indicated that properties of marine sediment (cation exchange capacity (CEC), organic matter, clay content, texture, type of clay mineral and size of soil particle) had effects on 137 Cs adsorption. CEC and clay content correlated positively with the accumulation of 137 Cs in the marine sediment samples. On the other hand, organic matter in sediment correlated negatively with the accumulation of 137 Cs in samples. The study of environmental effects (pH and potassium) found that the 137 Cs adsorption decreased when concentration of potassium increased. The pH effect is still unclear in this study because the differentiation of pH levels (6, 7, 8.3) did not have effects on 137 Cs adsorption in the samples.

  7. Sample Lesson Plans. Management for Effective Teaching.

    Science.gov (United States)

    Fairfax County Public Schools, VA. Dept. of Instructional Services.

    This guide is part of the Management for Effective Teaching (MET) support kit, a pilot project developed by the Fairfax County (Virginia) Public Schools to assist elementary school teachers in planning, managaing, and implementing the county's curriculum, Program of Studies (POS). In this guide, a sample lesson plan of a teaching-learning activity…

  8. The Relative Age Effect On The Selection In The Slovakia National Football Teams

    Directory of Open Access Journals (Sweden)

    Mikulič Martin

    2015-11-01

    Full Text Available The focus of this research was to determine the relative age effect (RAE on selection in the Slovakia national football teams. A factor that may have a significant impact on the quality of players chosen for the national teams or may result in a poor selection of players for the elite teams. Anthropometric and cognitive acceleration of players born in the first months of the calendar year concerning the overall context of the competition for placement in the national teams may be considered as a significant advantage. The aim of this research was to examine, determine and verify the presence of relative age effect in the selection of football players for the Slovakia national teams starting with the under 16 age category (U-16 through to the A - senior national football team. We presumed that the elite teams under this review and study consisted predominantly of players born in the first quarter of the calendar year, while also presuming that relative age effect receded with the increasing age category. Our survey sample U16 consisted of 79 players, U17 consisted of 47 players, U18 consisted of 58 players, U19 consisted of 71 players, U21 consisted of 52 players and A - senior national team consisted of 302 Slovakia national football players. The information obtained from the Slovak Football Association has been processed by the application of statistical methods and statistical significance test (T-test. Our research confirmed the presence of relative age effect in the U-16, U-17 and U-18 teams under our investigation (p≤0.01. In the U19 and U21 age categories, statistical significance has not been confirmed. As for the senior national team, statistically significant difference has been found in relation to players born in the last quarter of the year as opposed to players born in the first three months of the year (p≤0.01. Our results have shown that with the increasing age, the relative age effect fades and vanishes in full in the

  9. Is Black Hole Growth a Universal Process? Exploring Selection Effects in Measurements of AGN Accretion Rates and Host Galaxies.

    Science.gov (United States)

    Jones, Mackenzie

    2018-01-01

    At the center of essentially every massive galaxy is a monstrous black hole producing luminous radiation driven by the accretion of gas. By observing these active galactic nuclei (AGN) we may trace the growth of black holes across cosmic time. However, our knowledge of the full underlying AGN population is hindered by complex observational biases. My research aims to untangle these biases by using a novel approach to simulate the impact of selection effects on multiwavelength observations.The most statistically powerful studies of AGN to date come from optical spectroscopic surveys, with some reporting a complex relationship between AGN accretion rates and host galaxy characteristics. However, the optical waveband can be strongly influenced by selection effects and dilution from host galaxy star formation. I have shown that accounting for selection effects, the Eddington ratio distribution for optically-selected AGN is consistent with a broad power-law, as seen in the X-rays (Jones et al. 2016). This suggests that a universal Eddington ratio distribution may be enough to describe the full multiwavelength AGN population.Building on these results, I have expanded a semi-numerical galaxy formation simulation to include this straightforward prescription for AGN accretion and explicitly model selection effects. I have found that a simple model for AGN accretion can broadly reproduce the host galaxies and halos of X-ray AGN, and that different AGN selection techniques yield samples with very different host galaxy properties (Jones et al. 2017). Finally, I will discuss the capabilities of this simulation to build synthetic multiwavelength SEDs in order to explore what AGN populations would be detected with the next generation of observatories. This research is supported by a NASA Jenkins Graduate Fellowship under grant no. NNX15AU32H.

  10. 382 Effectiveness of Selected Communication Media on Tourism ...

    African Journals Online (AJOL)

    FIRST LADY

    2011-01-18

    Jan 18, 2011 ... Effectiveness of Selected Communication Media on Tourism ... communication is a means to education vis-à-vis education is a means .... Strategies in Extention. ... Marketing Profile Among Rural Households in South Eastern.

  11. Effect of tetracycline dose and treatment mode on selection of resistant coliform bacteria in nursery pigs

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders

    2017-01-01

    This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig...... by the time that the pigs left the nursery unit. The counts and proportions of tetracyclineresistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated...

  12. Accretion Properties of a Sample of Hard X-Ray (<60 keV) Selected Seyfert 1 Galaxies

    Science.gov (United States)

    Wang, J.; Mao, Y. F.; Wei, J. Y.

    2009-02-01

    We examine the accretion properties in a sample of 42 hard (3-60 keV) X-ray selected nearby broad-line active galactic nuclei (AGNs). The energy range in the sample is harder than that usually used in similar previous studies. These AGNs are mainly complied from the RXTE All Sky Survey, and complemented by the released INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN, and Eddington ratios are derived from their optical spectra in terms of the broad Hβ emission line. The tight correlation between the hard X-ray (3-20 keV) and bolometric/line luminosity is well identified in our sample. Also identified is a strong inverse Baldwin relationship of the Hβ emission line. In addition, all of these hard X-ray AGNs are biased toward luminous objects with a high Eddington ratio (mostly between 0.01 and 0.1) and a low column density (Simbol-X, and NeXT. Finally, the correlation between RFe (= optical Fe II/Hβ) and disk temperature as assessed by T vprop (L/L Edd)M -1 BH leads us to suggest that the strength of the Fe II emission is mainly determined by the shape of the ionizing spectrum.

  13. Parameters selection in gene selection using Gaussian kernel support vector machines by genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In microarray-based cancer classification, gene selection is an important issue owing to the large number of variables and small number of samples as well as its non-linearity. It is difficult to get satisfying results by using conventional linear statistical methods. Recursive feature elimination based on support vector machine (SVM RFE) is an effective algorithm for gene selection and cancer classification, which are integrated into a consistent framework. In this paper, we propose a new method to select parameters of the aforementioned algorithm implemented with Gaussian kernel SVMs as better alternatives to the common practice of selecting the apparently best parameters by using a genetic algorithm to search for a couple of optimal parameter. Fast implementation issues for this method are also discussed for pragmatic reasons. The proposed method was tested on two representative hereditary breast cancer and acute leukaemia datasets. The experimental results indicate that the proposed method performs well in selecting genes and achieves high classification accuracies with these genes.

  14. Calibration model maintenance in melamine resin production: Integrating drift detection, smart sample selection and model adaptation.

    Science.gov (United States)

    Nikzad-Langerodi, Ramin; Lughofer, Edwin; Cernuda, Carlos; Reischer, Thomas; Kantner, Wolfgang; Pawliczek, Marcin; Brandstetter, Markus

    2018-07-12

    selection of samples by active learning (AL) used for subsequent model adaptation is advantageous compared to passive (random) selection in case that a drift leads to persistent prediction bias allowing more rapid adaptation at lower reference measurement rates. Fully unsupervised adaptation using FLEXFIS-PLS could improve predictive accuracy significantly for light drifts but was not able to fully compensate for prediction bias in case of significant lack of fit w.r.t. the latent variable space. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Asymptotic Effectiveness of the Event-Based Sampling According to the Integral Criterion

    Directory of Open Access Journals (Sweden)

    Marek Miskowicz

    2007-01-01

    Full Text Available A rapid progress in intelligent sensing technology creates new interest in a development of analysis and design of non-conventional sampling schemes. The investigation of the event-based sampling according to the integral criterion is presented in this paper. The investigated sampling scheme is an extension of the pure linear send-on- delta/level-crossing algorithm utilized for reporting the state of objects monitored by intelligent sensors. The motivation of using the event-based integral sampling is outlined. The related works in adaptive sampling are summarized. The analytical closed-form formulas for the evaluation of the mean rate of event-based traffic, and the asymptotic integral sampling effectiveness, are derived. The simulation results verifying the analytical formulas are reported. The effectiveness of the integral sampling is compared with the related linear send-on-delta/level-crossing scheme. The calculation of the asymptotic effectiveness for common signals, which model the state evolution of dynamic systems in time, is exemplified.

  16. Assessment of reagent effectiveness and preservation methods for equine faecal samples

    Directory of Open Access Journals (Sweden)

    Eva Vavrouchova

    2015-03-01

    Full Text Available The aim of our study was to identify the most suitable flotation solution and effective preservation method for the examination of equine faeces samples using the FLOTAC technique. Samples from naturally infected horses were transported to the laboratory andanalysed accordingly. The sample from each horse was homogenized and divided into four parts: one was frozen, another two were preserved in different reagents such as sodium acetate-acetic-acid–formalin (SAF or 5% formalin.The last part was examined as a fresh sample in three different flotation solutions (Sheather´s solution, sodium chloride and sodium nitrate solution, all with a specific gravity 1.200. The preserved samples were examined in the period from 14 to21days after collection. According to our results, the sucrose solution was the most suitable flotation solution for fresh samples (small strongyle egg per gram was 706 compared to 360 in sodium chlorid and 507 in sodium nitrate and the sodium nitrate solution was the most efficient for the preserved samples (egg per gram was 382 compared to 295 in salt solution and 305 in sucrose solution. Freezing appears to be the most effective method of sample preservation, resulting in minimal damage to fragile strongyle eggs and therefore it is the most simple and effective preservation method for the examination of large numbers of faecal samples without the necessity of examining them all within 48 hours of collection. Deep freezing as a preservation method for equine faeces samples has not, according to our knowledge, been yet published.

  17. Getting DNA copy numbers without control samples.

    Science.gov (United States)

    Ortiz-Estevez, Maria; Aramburu, Ander; Rubio, Angel

    2012-08-16

    The selection of the reference to scale the data in a copy number analysis has paramount importance to achieve accurate estimates. Usually this reference is generated using control samples included in the study. However, these control samples are not always available and in these cases, an artificial reference must be created. A proper generation of this signal is crucial in terms of both noise and bias.We propose NSA (Normality Search Algorithm), a scaling method that works with and without control samples. It is based on the assumption that genomic regions enriched in SNPs with identical copy numbers in both alleles are likely to be normal. These normal regions are predicted for each sample individually and used to calculate the final reference signal. NSA can be applied to any CN data regardless the microarray technology and preprocessing method. It also finds an optimal weighting of the samples minimizing possible batch effects. Five human datasets (a subset of HapMap samples, Glioblastoma Multiforme (GBM), Ovarian, Prostate and Lung Cancer experiments) have been analyzed. It is shown that using only tumoral samples, NSA is able to remove the bias in the copy number estimation, to reduce the noise and therefore, to increase the ability to detect copy number aberrations (CNAs). These improvements allow NSA to also detect recurrent aberrations more accurately than other state of the art methods. NSA provides a robust and accurate reference for scaling probe signals data to CN values without the need of control samples. It minimizes the problems of bias, noise and batch effects in the estimation of CNs. Therefore, NSA scaling approach helps to better detect recurrent CNAs than current methods. The automatic selection of references makes it useful to perform bulk analysis of many GEO or ArrayExpress experiments without the need of developing a parser to find the normal samples or possible batches within the data. The method is available in the open-source R package

  18. [A comparison of convenience sampling and purposive sampling].

    Science.gov (United States)

    Suen, Lee-Jen Wu; Huang, Hui-Man; Lee, Hao-Hsien

    2014-06-01

    Convenience sampling and purposive sampling are two different sampling methods. This article first explains sampling terms such as target population, accessible population, simple random sampling, intended sample, actual sample, and statistical power analysis. These terms are then used to explain the difference between "convenience sampling" and purposive sampling." Convenience sampling is a non-probabilistic sampling technique applicable to qualitative or quantitative studies, although it is most frequently used in quantitative studies. In convenience samples, subjects more readily accessible to the researcher are more likely to be included. Thus, in quantitative studies, opportunity to participate is not equal for all qualified individuals in the target population and study results are not necessarily generalizable to this population. As in all quantitative studies, increasing the sample size increases the statistical power of the convenience sample. In contrast, purposive sampling is typically used in qualitative studies. Researchers who use this technique carefully select subjects based on study purpose with the expectation that each participant will provide unique and rich information of value to the study. As a result, members of the accessible population are not interchangeable and sample size is determined by data saturation not by statistical power analysis.

  19. 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 ...

  20. Effects of Low-Temperature Plasma-Sterilization on Mars Analog Soil Samples Mixed with Deinococcus radiodurans

    Directory of Open Access Journals (Sweden)

    Janosch Schirmack

    2016-05-01

    Full Text Available We used Ar plasma-sterilization at a temperature below 80 °C to examine its effects on the viability of microorganisms when intermixed with tested soil. Due to a relatively low temperature, this method is not thought to affect the properties of a soil, particularly its organic component, to a significant degree. The method has previously been shown to work well on spacecraft parts. The selected microorganism for this test was Deinococcus radiodurans R1, which is known for its remarkable resistance to radiation effects. Our results showed a reduction in microbial counts after applying a low temperature plasma, but not to a degree suitable for a sterilization of the soil. Even an increase of the treatment duration from 1.5 to 45 min did not achieve satisfying results, but only resulted in in a mean cell reduction rate of 75% compared to the untreated control samples.

  1. Evaluation of the effect of patient-selected music on sleep quality and pain intensity in burn patients

    Directory of Open Access Journals (Sweden)

    Mohaddes Ardabili Fatemeh

    2016-08-01

    Full Text Available Background and Objective: Sleep disturbances and pain are some of the most common problems among burn patients, which have adverse effects on recovery process and patient comfort. Given the use of music as a non-pharmacological approach to alleviate pain and provide comfort, this study aimed to evaluate the effect of patient-selected music on sleep quality and pain intensity in burn patients. Materials and Method: This clinical trial was conducted on burn patients hospitalized in one of the hospitals of Tehran, Iran in 2015. In total, 50 patients were selected using randomized convenience sampling and divided into two intervention (n=25 and control (n=25 groups. Intervention was carried out for the intervention group through playing instrumental music, selected by the patients, in three consecutive 45-minute sessions before sleep. Severity of pain in the participants was evaluated for three nights (before and five minutes after the intervention using visual analog scale (VAS. In addition, sleep quality of the samples was assessed three days before the intervention using Pittsburgh sleep quality index (PSQI and during the post-intervention days through interviews. The mentioned scales were applied for the control group as well. Data analysis was performed in SPSS version 18 using Chi-square, as well as paired and independent t-tests. Results: In this study, a significant improvement was observed in sleep quality (P<0.001  and pain intensity (P=0.012 in the participants of intervention group after listening to music. Moreover, a significant difference was observed between the study groups after the intervention in terms of mean sleep quality score (P<0.001 and pain intensity (P=0.046. Conclusion: According to the results of this study, application of patient-selected music therapy could be associated with a significant improve in sleep quality and decrease in pain intensity in burn patients. Therefore, it is recommended that this intervention

  2. Sampling dynamics: an alternative to payoff-monotone selection dynamics

    DEFF Research Database (Denmark)

    Berkemer, Rainer

    payoff-monotone nor payoff-positive which has interesting consequences. This can be demonstrated by application to the travelers dilemma, a deliberately constructed social dilemma. The game has just one symmetric Nash equilibrium which is Pareto inefficient. Especially when the travelers have many......'' of the standard game theory result. Both, analytical tools and agent based simulation are used to investigate the dynamic stability of sampling equilibria in a generalized travelers dilemma. Two parameters are of interest: the number of strategy options (m) available to each traveler and an experience parameter...... (k), which indicates the number of samples an agent would evaluate before fixing his decision. The special case (k=1) can be treated analytically. The stationary points of the dynamics must be sampling equilibria and one can calculate that for m>3 there will be an interior solution in addition...

  3. H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. I. OPTICAL DATA

    International Nuclear Information System (INIS)

    West, Andrew A.; Garcia-Appadoo, Diego A.; Dalcanton, Julianne J.; Ivezic, Zeljko; Bentz, Misty C.; Disney, Mike J.; Rockosi, Constance M.; Brinkmann, J.

    2010-01-01

    We present the optical data for 195 H I-selected galaxies that fall within both the Sloan Digital Sky Survey (SDSS) and the Parkes Equatorial Survey (ES). The photometric quantities have been independently recomputed for our sample using a new photometric pipeline optimized for large galaxies, thus correcting for SDSS's limited reliability for automatic photometry of angularly large or low surface brightness (LSB) galaxies. We outline the magnitude of the uncertainty in the SDSS catalog-level photometry and derive a quantitative method for correcting the over-sky subtraction in the SDSS photometric pipeline. The main thrust of this paper is to present the ES/SDSS sample and discuss the methods behind the improved photometry, which will be used in future scientific analysis. We present the overall optical properties of the sample and briefly compare to a volume-limited, optically selected sample. Compared to the optically selected SDSS sample (in the similar volume), H I-selected galaxies are bluer and more luminous (fewer dwarf ellipticals and more star formation). However, compared to typical SDSS galaxy studies, which have their own selection effect, our sample is bluer, fainter, and less massive.

  4. Selecting cost-effective areas for restoration of ecosystem services.

    Science.gov (United States)

    Adame, M F; Hermoso, V; Perhans, K; Lovelock, C E; Herrera-Silveira, J A

    2015-04-01

    Selection of areas for restoration should be based on cost-effectiveness analysis to attain the maximum benefit with a limited budget and overcome the traditional ad hoc allocation of funds for restoration projects. Restoration projects need to be planned on the basis of ecological knowledge and economic and social constraints. We devised a novel approach for selecting cost-effective areas for restoration on the basis of biodiversity and potential provision of 3 ecosystem services: carbon storage, water depuration, and coastal protection. We used Marxan, a spatial prioritization tool, to balance the provision of ecosystem services against the cost of restoration. We tested this approach in a mangrove ecosystem in the Caribbean. Our approach efficiently selected restoration areas that at low cost were compatible with biodiversity targets and that maximized the provision of one or more ecosystem services. Choosing areas for restoration of mangroves on the basis carbon storage potential, largely guaranteed the restoration of biodiversity and other ecosystem services. © 2014 Society for Conservation Biology.

  5. Forward selection two sample binomial test

    Science.gov (United States)

    Wong, Kam-Fai; Wong, Weng-Kee; Lin, Miao-Shan

    2016-01-01

    Fisher’s exact test (FET) is a conditional method that is frequently used to analyze data in a 2 × 2 table for small samples. This test is conservative and attempts have been made to modify the test to make it less conservative. For example, Crans and Shuster (2008) proposed adding more points in the rejection region to make the test more powerful. We provide another way to modify the test to make it less conservative by using two independent binomial distributions as the reference distribution for the test statistic. We compare our new test with several methods and show that our test has advantages over existing methods in terms of control of the type 1 and type 2 errors. We reanalyze results from an oncology trial using our proposed method and our software which is freely available to the reader. PMID:27335577

  6. Biological activity of selected plants with adaptogenic effect

    Directory of Open Access Journals (Sweden)

    Eva Ivanišová

    2016-05-01

    Full Text Available The aim of this study was to determine biological activity of plants with adaptogenic effect: Panax ginseng Mayer., Withania somnifera L., Eleuterococcus senticosus Rupr. et Maxim., Astragallus membranaceus Fisch. and Codonopsis pilosulae Franch. The antioxidant activity was detected by DPPH and phosphomolybdenum method, total polyphenol content with Folin – Ciocalteu reagent, flavonoids content by aluminium chloride method. The detection of antimicrobial activity was carried out by disc diffusion method against three species of Gram-negative bacteria: Escherichia coli CCM 3988, Salmonella enterica subsp. enterica CCM 3807, Yersinia enterocolitica CCM 5671 and two Gram-positive bacteria: Bacillus thuringiensis CCM 19, Stapylococcus aureus subsp. aureus CCM 2461. Results showed that plants with adaptogenic effect are rich for biologically active substances. The highest antioxidant activity by DPPH method was determined in the sample of Eleuterococcus senticosus (3.15 mg TEAC – Trolox equivalent antioxidant capacity per g of sample and by phosphomolybdenum method in the sample of Codonopsis pilosulae (188.79 mg TEAC per g of sample. In the sample of Panax ginseng was measured the highest content of total polyphenols (8.10 mg GAE – galic acid equivalent per g of sample and flavonoids (3.41 μg QE – quercetin equivalent per g of sample. All samples also showed strong antimicrobial activity with the best results in Panax ginseng and Withania somnifera in particular for species Yersinia enterocolitica CCM 5671 and Salmonella enterica subsp. enterica CCM 3807. The analyzed species of plant with high value of biological activity can be used more in the future, not only in food, but also in cosmetics and pharmaceutical industries.

  7. Behavior of Phenols and Phenoxyacids on a Bisphenol-A Imprinted Polymer. Application for Selective Solid-Phase Extraction from Water and Urine Samples

    Directory of Open Access Journals (Sweden)

    Eliseo Herrero-Hernández

    2011-05-01

    Full Text Available A molecularly imprinted polymer (MIP, obtained by precipitation polymerisation with 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as cross-linker, and bisphenol-A (BPA as template, was prepared. The binding site configuration of the BPA-MIP was examined using Scatchard analysis. Moreover, the behaviour of the BPA-MIP for the extraction of several phenolic compounds (bisphenol-A, bisphenol-F, 4-nitrophenol, 3-methyl-4-nitrophenol and phenoxyacid herbicides such as 2,4-D, 2,4,5-T and 2,4,5-TP has been studied in organic and aqueous media in the presence of other pesticides in common use. It was possible to carry out the selective preconcentration of the target analytes from the organic medium with recoveries of higher than 70%. In an aqueous medium, hydrophobic interactions were found to exert a remarkably non-specific contribution to the overall binding process. Several parameters affecting the extraction efficiency of the BPA-MIP were evaluated to achieve the selective preconcentration of phenols and phenoxyacids from aqueous samples. The possibility of using the BPA-MIP as a selective sorbent to preconcentrate these compounds from other samples such as urine and river water was also explored.

  8. The relative age effect in the German Football TID Programme: biases in motor performance diagnostics and effects on single motor abilities and skills in groups of selected players.

    Science.gov (United States)

    Votteler, Andreas; Höner, Oliver

    2014-01-01

    This study examined the disturbing effects of relative age on the talent identification process in the talent development programme of the German Football Association. The bias in the selection rate was examined via the extent of relative age effects. The bias in motor performance diagnostics was analysed by comparing the motor performance of selected players with normal motor development. The mechanisms underlying the relative age biases in motor performance were examined by modelling the direct and indirect effects of relative age on single motor performance tests for sprint, running agility, dribbling and ball passing and control. Data from 10,130 selected football players from the U12 to U15 age groups were collected in autumn 2010. The birth distribution differed significantly from the reference population with approximately 61% of the players born in the first half of the year. The selection probability was approximately two times higher for players born in the first quarter of the year than for players born in the last quarter. Revised motor performance diagnostics showed better results on average for relatively younger players. Path analysis revealed significant direct and indirect relative age effects for physiologically demanding tests and almost no effects for technically demanding tests. Large sample sizes allowed high resolution in relative age with additional informational content and multivariate modelling of the complex relationships among relative age, physical development and motor performance. The results are discussed on how relative age affects the effectiveness and fairness of talent identification and development processes.

  9. Neural evidence reveals the rapid effects of reward history on selective attention.

    Science.gov (United States)

    MacLean, Mary H; Giesbrecht, Barry

    2015-05-05

    Selective attention is often framed as being primarily driven by two factors: task-relevance and physical salience. However, factors like selection and reward history, which are neither currently task-relevant nor physically salient, can reliably and persistently influence visual selective attention. The current study investigated the nature of the persistent effects of irrelevant, physically non-salient, reward-associated features. These features affected one of the earliest reliable neural indicators of visual selective attention in humans, the P1 event-related potential, measured one week after the reward associations were learned. However, the effects of reward history were moderated by current task demands. The modulation of visually evoked activity supports the hypothesis that reward history influences the innate salience of reward associated features, such that even when no longer relevant, nor physically salient, these features have a rapid, persistent, and robust effect on early visual selective attention. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Sampling Efficiency and Performance of Selected Thoracic Aerosol Samplers.

    Science.gov (United States)

    Görner, Peter; Simon, Xavier; Boivin, Alexis; Bau, Sébastien

    2017-08-01

    Measurement of worker exposure to a thoracic health-related aerosol fraction is necessary in a number of occupational situations. This is the case of workplaces with atmospheres polluted by fibrous particles, such as cotton dust or asbestos, and by particles inducing irritation or bronchoconstriction such as acid mists or flour dust. Three personal and two static thoracic aerosol samplers were tested under laboratory conditions. Sampling efficiency with respect to particle aerodynamic diameter was measured in a horizontal low wind tunnel and in a vertical calm air chamber. Sampling performance was evaluated against conventional thoracic penetration. Three of the tested samplers performed well, when sampling the thoracic aerosol at nominal flow rate and two others performed well at optimized flow rate. The limit of flow rate optimization was found when using cyclone samplers. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  11. Molecularly imprinted layer-coated silica nanoparticles for selective solid-phase extraction of bisphenol A from chemical cleansing and cosmetics samples

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Rong; Zhao Wenhui; Zhai Meijuan; Wei Fangdi; Cai Zheng; Sheng Na [School of Pharmacy, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu 210029 (China); Hu Qin, E-mail: huqin@njmu.edu.cn [School of Pharmacy, Nanjing Medical University, Hanzhong Road 140, Nanjing, Jiangsu 210029 (China)

    2010-01-25

    Highly selective molecularly imprinted layer-coated silica nanoparticles for bisphenol A (BPA) were synthesized by molecular imprinting technique with a sol-gel process on the supporter of silica nanoparticles. The BPA-imprinted silica nanoparticles were characterized by fourier transform infrared spectrometer, transmission electron microscope, dynamic adsorption and static adsorption tests. The equilibrium association constant, K{sub a}, and the apparent maximum number of binding sites, Q{sub max}, were estimated to be 1.25 x 10{sup 5} mL {mu}mol{sup -1} and 16.4 {mu}mol g{sup -1}, respectively. The BPA-imprinted silica nanoparticles solid-phase extraction (SPE) column had higher selectivity for BPA than the commercial C18-SPE column. The results of the study indicated that the prepared BPA-imprinted silica nanoparticles exhibited high adsorption capacity and selectivity, and offered a fast kinetics for the rebinding of BPA. The BPA-imprinted silica nanoparticles were successfully used in SPE to selectively enrich and determine BPA from shampoo, bath lotion and cosmetic cream samples.

  12. Effects of squats accompanied by hip joint adduction on the selective activity of the vastus medialis oblique.

    Science.gov (United States)

    Hyong, In Hyouk

    2015-06-01

    [Purpose] This study evaluated the effective selective activation method of the vastus medialis oblique for knee joint stabilization in patients with patellofemoral pain syndrome. [Subjects and Methods] Fifteen healthy college students (9 males, 6 females); mean age, height, and weight: 22.2 years, 167.8 cm, and 61.4 kg, respectively) participated. The knee angle was held at 60°. Muscle activities were measured once each during an ordinary squat and a squat accompanied by hip joint adduction. The muscle activities of the vastus medialis oblique and vastus lateralis were measured by electromyography for five seconds while maintaining 60° knee flexion. Electromyography signals were obtained at a sampling rate of 1,000 Hz and band pass filtering at 20-50 Hz. The obtained raw root mean square was divided by the maximal voluntary isometric contraction and expressed as a percentage. The selective activity of the vastus medialis oblique was assessed according to the muscle activity ratio of the vastus medialis oblique to the vastus lateralis. [Results] The activity ratio of the vastus medialis oblique was higher during a squat with hip joint adduction than without. [Conclusion] A squat accompanied by hip joint adduction is effective for the selective activation of the vastus medialis oblique.

  13. Effect of sampling and short isolation methodologies on the recovery of human pathogenic Yersinia enterocolitica from pig tonsils.

    Science.gov (United States)

    Van Damme, Inge; Berkvens, Dirk; De Zutter, Lieven

    2012-07-01

    The objective of this study was to determine the effect of sampling (swab samples compared to destructive samples) on isolation rates of human pathogenic Yersinia enterocolitica from pig tonsils. Moreover, the relative efficiency of different rapid, routinely applicable isolation methods was evaluated. Therefore, swab and destructive samples from tonsils of 120 pigs at slaughter were analyzed in parallel using direct plating and different enrichment methods. Salmonella-Shigella-desoxycholate-calcium chloride (SSDC) agar, cefsulodin-irgasan-novobiocin (CIN) agar, and Yersinia enterocolitica chromogenic medium (YeCM) were used as selective agar media. For enrichment, irgasan-ticarcillin-potassium chlorate (ITC) broth and peptone-sorbitol-bile (PSB) broth were incubated at 25°C for 48 h. Overall, 55 tonsils (45.8%) were positive for Y. enterocolitica bioserotype 4/O:3. Recovery was significantly higher using the destructive method compared to the swabbing method. Direct plating resulted in 47 and 28 Y. enterocolitica-positive destructive and swab samples, respectively. Alkali treatment of PSB and ITC enrichment broths significantly increased recovery of pathogenic Y. enterocolitica from destructive tonsil samples. The performance of YeCM for qualitative and quantitative isolation of pathogenic Y. enterocolitica from pig tonsils was equal to SSDC and CIN. In conclusion, direct plating and ISO 10273: 2003 with minor modifications are suitable and rapid methods for isolation of pathogenic Y. enterocolitica from destructive tonsil samples.

  14. Sampling frequency affects ActiGraph activity counts

    DEFF Research Database (Denmark)

    Brønd, Jan Christian; Arvidsson, Daniel

    that is normally performed at frequencies higher than 2.5 Hz. With the ActiGraph model GT3X one has the option to select sample frequency from 30 to 100 Hz. This study investigated the effect of the sampling frequency on the ouput of the bandpass filter.Methods: A synthetic frequency sweep of 0-15 Hz was generated...... in Matlab and sampled at frequencies of 30-100 Hz. Also, acceleration signals during indoor walking and running were sampled at 30 Hz using the ActiGraph GT3X and resampled in Matlab to frequencies of 40-100 Hz. All data was processed with the ActiLife software.Results: Acceleration frequencies between 5......-15 Hz escaped the bandpass filter when sampled at 40, 50, 70, 80 and 100 Hz, while this was not the case when sampled at 30, 60 and 90 Hz. During the ambulatory activities this artifact resultet in different activity count output from the ActiLife software with different sampling frequency...

  15. Effect of dissolved organic matter on pre-equilibrium passive sampling: A predictive QSAR modeling study.

    Science.gov (United States)

    Lin, Wei; Jiang, Ruifen; Shen, Yong; Xiong, Yaxin; Hu, Sizi; Xu, Jianqiao; Ouyang, Gangfeng

    2018-04-13

    Pre-equilibrium passive sampling is a simple and promising technique for studying sampling kinetics, which is crucial to determine the distribution, transfer and fate of hydrophobic organic compounds (HOCs) in environmental water and organisms. Environmental water samples contain complex matrices that complicate the traditional calibration process for obtaining the accurate rate constants. This study proposed a QSAR model to predict the sampling rate constants of HOCs (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides) in aqueous systems containing complex matrices. A homemade flow-through system was established to simulate an actual aqueous environment containing dissolved organic matter (DOM) i.e. humic acid (HA) and (2-Hydroxypropyl)-β-cyclodextrin (β-HPCD)), and to obtain the experimental rate constants. Then, a quantitative structure-activity relationship (QSAR) model using Genetic Algorithm-Multiple Linear Regression (GA-MLR) was found to correlate the experimental rate constants to the system state including physicochemical parameters of the HOCs and DOM which were calculated and selected as descriptors by Density Functional Theory (DFT) and Chem 3D. The experimental results showed that the rate constants significantly increased as the concentration of DOM increased, and the enhancement factors of 70-fold and 34-fold were observed for the HOCs in HA and β-HPCD, respectively. The established QSAR model was validated as credible (R Adj. 2 =0.862) and predictable (Q 2 =0.835) in estimating the rate constants of HOCs for complex aqueous sampling, and a probable mechanism was developed by comparison to the reported theoretical study. The present study established a QSAR model of passive sampling rate constants and calibrated the effect of DOM on the sampling kinetics. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. The effect of self-selected soothing music on fistula puncture-related pain in hemodialysis patients.

    Science.gov (United States)

    Shabandokht-Zarmi, Hosniyeh; Bagheri-Nesami, Masoumeh; Shorofi, Seyed Afshin; Mousavinasab, Seyed Nouraddin

    2017-11-01

    This study was intended to examine the effect of selective soothing music on fistula puncture-related pain in hemodialysis patients. This is a randomized clinical trial in which 114 participants were selected from two hemodialysis units by means of a non-random, convenience sampling method. The participants were then allocated in three groups of music (N = 38), headphone (N = 38), and control (N = 38). The fistula puncture-related pain was measured 1 min after venipuncture procedure in all three groups. The music group listened to their self-selected and preferred music 6 min before needle insertion into a fistula until the end of procedure. The headphone group wore a headphone alone without listening to music 6 min before needle insertion into a fistula until the end of procedure. The control group did not receive any intervention from the research team during needle insertion into a fistula. The pain intensity was measured immediately after the intervention in all three groups. This study showed a significant difference between the music and control groups, and the music and headphone groups in terms of the mean pain score after the intervention. However, the analysis did not indicate any significant difference between the headphone and control groups with regard to the mean pain score after the intervention. It is concluded that music can be used effectively for pain related to needle insertion into a fistula in hemodialysis patients. Future research should investigate the comparative effects of pharmacological and non-pharmacological interventions on fistula puncture-related pain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Sample size methodology

    CERN Document Server

    Desu, M M

    2012-01-01

    One of the most important problems in designing an experiment or a survey is sample size determination and this book presents the currently available methodology. It includes both random sampling from standard probability distributions and from finite populations. Also discussed is sample size determination for estimating parameters in a Bayesian setting by considering the posterior distribution of the parameter and specifying the necessary requirements. The determination of the sample size is considered for ranking and selection problems as well as for the design of clinical trials. Appropria

  18. 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...

  19. Sampling and farm stories prompt consumers to buy specialty cheeses

    OpenAIRE

    Reed, Barbara A.; Bruhn, Christine M.

    2003-01-01

    California specialty cheese makers need information on what drives product sales so they can effectively market their products. Focus group and telephone research revealed that specialty cheese consumers have a strong preference for sampling cheese before making a purchase. Consumers also rely heavily on staff recommendations to select cheese. They appreciate unlimited sampling in an unhurried, low-pressure environment. Specialty cheese consumers consider themselves “food experimenters”; they...

  20. SELECTING QUASARS BY THEIR INTRINSIC VARIABILITY

    International Nuclear Information System (INIS)

    Schmidt, Kasper B.; Rix, Hans-Walter; Jester, Sebastian; Hennawi, Joseph F.; Marshall, Philip J.; Dobler, Gregory

    2010-01-01

    We present a new and simple technique for selecting extensive, complete, and pure quasar samples, based on their intrinsic variability. We parameterize the single-band variability by a power-law model for the light-curve structure function, with amplitude A and power-law index γ. We show that quasars can be efficiently separated from other non-variable and variable sources by the location of the individual sources in the A-γ plane. We use ∼60 epochs of imaging data, taken over ∼5 years, from the SDSS stripe 82 (S82) survey, where extensive spectroscopy provides a reference sample of quasars, to demonstrate the power of variability as a quasar classifier in multi-epoch surveys. For UV-excess selected objects, variability performs just as well as the standard SDSS color selection, identifying quasars with a completeness of 90% and a purity of 95%. In the redshift range 2.5 < z < 3, where color selection is known to be problematic, variability can select quasars with a completeness of 90% and a purity of 96%. This is a factor of 5-10 times more pure than existing color selection of quasars in this redshift range. Selecting objects from a broad griz color box without u-band information, variability selection in S82 can afford completeness and purity of 92%, despite a factor of 30 more contaminants than quasars in the color-selected feeder sample. This confirms that the fraction of quasars hidden in the 'stellar locus' of color space is small. To test variability selection in the context of Pan-STARRS 1 (PS1) we created mock PS1 data by down-sampling the S82 data to just six epochs over 3 years. Even with this much sparser time sampling, variability is an encouragingly efficient classifier. For instance, a 92% pure and 44% complete quasar candidate sample is attainable from the above griz-selected catalog. Finally, we show that the presented A-γ technique, besides selecting clean and pure samples of quasars (which are stochastically varying objects), is also

  1. 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.

  2. Selective extraction of emerging contaminants from water samples by dispersive liquid-liquid microextraction using functionalized ionic liquids.

    Science.gov (United States)

    Yao, Cong; Li, Tianhao; Twu, Pamela; Pitner, William R; Anderson, Jared L

    2011-03-25

    Functionalized ionic liquids containing the tris(pentafluoroethyl)trifluorophosphate (FAP) anion were used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the extraction of 14 emerging contaminants from water samples. The extraction efficiencies and selectivities were compared to those of an in situ IL DLLME method which uses an in situ metathesis reaction to exchange 1-butyl-3-methylimidazolium chloride (BMIM-Cl) to 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (BMIM-NTf(2)). Compounds containing tertiary amine functionality were extracted with high selectivity and sensitivity by the 1-(6-amino-hexyl)-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate (HNH(2)MPL-FAP) IL compared to other FAP-based ILs and the BMIM-NTf(2) IL. On the other hand, polar or acidic compounds without amine groups exhibited higher enrichment factors using the BMIM-NTf(2) IL. The detection limits for the studied analytes varied from 0.1 to 55.1 μg/L using the traditional IL DLLME method with the HNH(2)MPL-FAP IL as extraction solvent, and from 0.1 to 55.8 μg/L using in situ IL DLLME method with BMIM-Cl+LiNTf(2) as extraction solvent. A 93-fold decrease in the detection limit of caffeine was observed when using the HNH(2)MPL-FAP IL compared to that obtained using in situ IL DLLME method. Real water samples including tap water and creek water were analyzed with both IL DLLME methods and yielded recoveries ranging from 91% to 110%. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Discrimination of handlebar grip samples by fourier transform infrared microspectroscopy analysis and statistics

    Directory of Open Access Journals (Sweden)

    Zeyu Lin

    2017-01-01

    Full Text Available In this paper, the authors presented a study on the discrimination of handlebar grip samples, to provide effective forensic science service for hit and run traffic cases. 50 bicycle handlebar grip samples, 49 electric bike handlebar grip samples, and 96 motorcycle handlebar grip samples have been randomly collected by the local police in Beijing (China. Fourier transform infrared microspectroscopy (FTIR was utilized as analytical technology. Then, target absorption selection, data pretreatment, and discrimination of linked samples and unlinked samples were chosen as three steps to improve the discrimination of FTIR spectrums collected from different handlebar grip samples. Principal component analysis and receiver operating characteristic curve were utilized to evaluate different data selection methods and different data pretreatment methods, respectively. It is possible to explore the evidential value of handlebar grip residue evidence through instrumental analysis and statistical treatments. It will provide a universal discrimination method for other forensic science samples as well.

  4. Ion-selective field-effect transitors. A sensor for lithium and calcium

    International Nuclear Information System (INIS)

    Kharitonov, A.B.; Petrukhin, O.M.; Nad', V.Yh.; Ypivakov, B.Ya.; Myasoedov, B.F.; Otmakhova, O.A.; Tal'roze, R.V.; Plateh, N.A.

    1997-01-01

    An Li-sensitive sensor based on a field-effect transistor with a tantalum pentoxide gate and a poly(vinyl chloride) membrane based on diethylene glycol bis-o-2-diphenylphosphinylmethyl phenyl ether is developed. THis sensor exhibits analytical characteristics close to those of a lithium-selective electrode analogous in membrane composition; it is insensitive to the concentration of hydrogen ions in the pH range 4.5-8.5. The service life of the sensor is no shorter than four months, which is comparable to the service life of the corresponding ion-selective electrode. A bifunctional sensor for Ca and Li is prepared based on membranes used for preparing the corresponding monofunctional ion-selective field-effect transistors; this sensor exhibits analytical characteristics close to those of ion-selective electrodes and monofunctional sensors. 12 refs., 6 figs., 2 tabs

  5. The impact of sample size and marker selection on the study of haplotype structures

    Directory of Open Access Journals (Sweden)

    Sun Xiao

    2004-03-01

    Full Text Available Abstract Several studies of haplotype structures in the human genome in various populations have found that the human chromosomes are structured such that each chromosome can be divided into many blocks, within which there is limited haplotype diversity. In addition, only a few genetic markers in a putative block are needed to capture most of the diversity within a block. There has been no systematic empirical study of the effects of sample size and marker set on the identified block structures and representative marker sets, however. The purpose of this study was to conduct a detailed empirical study to examine such impacts. Towards this goal, we have analysed three representative autosomal regions from a large genome-wide study of haplotypes with samples consisting of African-Americans and samples consisting of Japanese and Chinese individuals. For both populations, we have found that the sample size and marker set have significant impact on the number of blocks and the total number of representative markers identified. The marker set in particular has very strong impacts, and our results indicate that the marker density in the original datasets may not be adequate to allow a meaningful characterisation of haplotype structures. In general, we conclude that we need a relatively large sample size and a very dense marker panel in the study of haplotype structures in human populations.

  6. Bayesian sample size determination for cost-effectiveness studies with censored data.

    Directory of Open Access Journals (Sweden)

    Daniel P Beavers

    Full Text Available Cost-effectiveness models are commonly utilized to determine the combined clinical and economic impact of one treatment compared to another. However, most methods for sample size determination of cost-effectiveness studies assume fully observed costs and effectiveness outcomes, which presents challenges for survival-based studies in which censoring exists. We propose a Bayesian method for the design and analysis of cost-effectiveness data in which costs and effectiveness may be censored, and the sample size is approximated for both power and assurance. We explore two parametric models and demonstrate the flexibility of the approach to accommodate a variety of modifications to study assumptions.

  7. Towards quantitative laser-induced breakdown spectroscopy analysis of soil samples

    International Nuclear Information System (INIS)

    Bousquet, B.; Sirven, J.-B.; Canioni, L.

    2007-01-01

    A quantitative analysis of chromium in soil samples is presented. Different emission lines related to chromium are studied in order to select the best one for quantitative features. Important matrix effects are demonstrated from one soil to the other, preventing any prediction of concentration in different soils on the basis of a univariate calibration curve. Finally, a classification of the LIBS data based on a series of Principal Component Analyses (PCA) is applied to a reduced dataset of selected spectral lines related to the major chemical elements in the soils. LIBS data of heterogeneous soils appear to be widely dispersed, which leads to a reconsideration of the sampling step in the analysis process

  8. Task-selective memory effects for successfully implemented encoding strategies.

    Science.gov (United States)

    Leshikar, Eric D; Duarte, Audrey; Hertzog, Christopher

    2012-01-01

    Previous behavioral evidence suggests that instructed strategy use benefits associative memory formation in paired associate tasks. Two such effective encoding strategies--visual imagery and sentence generation--facilitate memory through the production of different types of mediators (e.g., mental images and sentences). Neuroimaging evidence suggests that regions of the brain support memory reflecting the mental operations engaged at the time of study. That work, however, has not taken into account self-reported encoding task success (i.e., whether participants successfully generated a mediator). It is unknown, therefore, whether task-selective memory effects specific to each strategy might be found when encoding strategies are successfully implemented. In this experiment, participants studied pairs of abstract nouns under either visual imagery or sentence generation encoding instructions. At the time of study, participants reported their success at generating a mediator. Outside of the scanner, participants further reported the quality of the generated mediator (e.g., images, sentences) for each word pair. We observed task-selective memory effects for visual imagery in the left middle occipital gyrus, the left precuneus, and the lingual gyrus. No such task-selective effects were observed for sentence generation. Intriguingly, activity at the time of study in the left precuneus was modulated by the self-reported quality (vividness) of the generated mental images with greater activity for trials given higher ratings of quality. These data suggest that regions of the brain support memory in accord with the encoding operations engaged at the time of study.

  9. Systematic sampling for suspended sediment

    Science.gov (United States)

    Robert B. Thomas

    1991-01-01

    Abstract - Because of high costs or complex logistics, scientific populations cannot be measured entirely and must be sampled. Accepted scientific practice holds that sample selection be based on statistical principles to assure objectivity when estimating totals and variances. Probability sampling--obtaining samples with known probabilities--is the only method that...

  10. Selective decontamination of the digestive tract and selective oropharyngeal decontamination in intensive care unit patients: a cost-effectiveness analysis

    NARCIS (Netherlands)

    Oostdijk, E.A.; Wit, G.A. de; Bakker, M; Smet, A.M. de; Bonten, M.J.; Hoeven, J.G. van der; Pickkers, P.; Sturm, P.D.J.; Voss, A.; et al.,

    2013-01-01

    OBJECTIVE: To determine costs and effects of selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) as compared with standard care (ie, no SDD/SOD (SC)) from a healthcare perspective in Dutch Intensive Care Units (ICUs). DESIGN: A post hoc analysis of a

  11. Selective decontamination of the digestive tract and selective oropharyngeal decontamination in intensive care unit patients : a cost-effectiveness analysis

    NARCIS (Netherlands)

    Oostdijk, Evelien A. N.; de Wit, G. A.; Bakker, Marina; de Smet, Anne-Marie; Bonten, M. J. M.

    2013-01-01

    Objective: To determine costs and effects of selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) as compared with standard care (ie, no SDD/SOD (SC)) from a healthcare perspective in Dutch Intensive Care Units (ICUs). Design: A post hoc analysis of a

  12. A QUASI EXPERIMENTAL STUDY TO EVALUATE EFFECTIVENESS OF GLYCERIN MAGNESIUM SULPHATE DRESSING ON PHLEBITIS AMONG PATIENTS UNDERGOING PERIPHERAL INTRAVENOUS INFUSION IN SELECTED HOSPITAL,VADODARA

    Directory of Open Access Journals (Sweden)

    Ravindra HN, Patel Krupa D

    2015-07-01

    Full Text Available Introduction: Intravenous therapy is indicated for many reasons. A significant number of patients admitted into hospital receive some forms of intravenous therapy through peripheral venous cannula, which is a common procedure carried out in hospital to allow rapid and accurate administration of medication. However, the intravenous cannulation can have undesirable effects, the most of which is phlebitis, which is due to mechanical, chemical or infectious cause. Method: In this study quasi-experimental research approach was used. Non probability purposive sampling technique was used to select the sample from the selected hospital. The research design adopted for the study was pre-test, post-test control group design. In the present study a sample of 60 hospitalised patients and who met the inclusion criteria was selected from the target population. In this study the instruments used are baseline Performa, structured interview schedule to assess the subjective symptoms and observation scale to observe the objective symptoms. Result: In experimental group post test mean score 1.10, SD was 0.71 respectively. In control group post test mean score 2.53, SD was 0.78 respectively. The obtained value 7.454 statistically was significant at 0.001 levels. So research hypothesis was accepted. So there was significant difference between post intervention phlebitis among the experimental group and control group. Discussion: In the research study findings revealed that Glycerin Magnesium sulphate dressing is highly effective in decrease phlebitis level to the patients.

  13. Effect of repeated administration of Damiana on selected kidney ...

    African Journals Online (AJOL)

    The effect of repeated oral administration of Damiana, an aphrodisiac, on selected renal function indices of male rats for 20 days was investigated. Male rats were orally administered with appropriate volume corresponding to human therapeutic dose of 3.6mg/kg body weight of diamiana at 24hour intervals. The effects on ...

  14. Brittleness and Packing Density Effects on Blast-hole Cuttings Yield of Selected Rocks

    Directory of Open Access Journals (Sweden)

    B. Adebayo

    2016-06-01

    Full Text Available This paper evaluates brittleness and packing density to analysis their effects on blast-hole cutting yield for three selected rocks in Nigeria. Brittleness test (S20 was carried out in accordance with Norwegian Soil and Rock Engineering and the Brittleness Index (BI for the selected rocks were estimated. The packing density determined from the photomicrograph of the rock samples. The grain size of 45 blast-holes drill cuttings collected from three selected while drilling of these rocks were determined using standard method of America Society for Testing and Materials (ASTM D 2487. The brittleness values are 50%, 44% and 42% for micro granite, porphyritic granite and medium biotite granite respectively. The result of BI varied from 10.32 – 11.59 and they are rated as moderately brittle rocks. The values of packing density varied from 92.20 – 94.55%, 91.00 -92.96% and 92.92 – 94.96% for all the rocks. The maximum weights of blast-hole particle size retained at 75 µm are 106.00g, 103.28 g and 99.76 g for medium biotite granite, micro granite and porhyritic granite respectively. Packing density values have correlation to some extent with (S20 values hence, this influence the yield of blast-hole cuttings as drilling progresses. The minimum weight of blast-hole cuttings particle size retained at 150 µm agrees with brittleness index classification for micro granite.

  15. Coordination of Conditional Poisson Samples

    Directory of Open Access Journals (Sweden)

    Grafström Anton

    2015-12-01

    Full Text Available Sample coordination seeks to maximize or to minimize the overlap of two or more samples. The former is known as positive coordination, and the latter as negative coordination. Positive coordination is mainly used for estimation purposes and to reduce data collection costs. Negative coordination is mainly performed to diminish the response burden of the sampled units. Poisson sampling design with permanent random numbers provides an optimum coordination degree of two or more samples. The size of a Poisson sample is, however, random. Conditional Poisson (CP sampling is a modification of the classical Poisson sampling that produces a fixed-size πps sample. We introduce two methods to coordinate Conditional Poisson samples over time or simultaneously. The first one uses permanent random numbers and the list-sequential implementation of CP sampling. The second method uses a CP sample in the first selection and provides an approximate one in the second selection because the prescribed inclusion probabilities are not respected exactly. The methods are evaluated using the size of the expected sample overlap, and are compared with their competitors using Monte Carlo simulation. The new methods provide a good coordination degree of two samples, close to the performance of Poisson sampling with permanent random numbers.

  16. The Effect of Sample Size and Data Numbering on Precision of Calibration Model to predict Soil Properties

    Directory of Open Access Journals (Sweden)

    H Mohamadi Monavar

    2017-10-01

    Full Text Available Introduction Precision agriculture (PA is a technology that measures and manages within-field variability, such as physical and chemical properties of soil. The nondestructive and rapid VIS-NIR technology detected a significant correlation between reflectance spectra and the physical and chemical properties of soil. On the other hand, quantitatively predict of soil factors such as nitrogen, carbon, cation exchange capacity and the amount of clay in precision farming is very important. The emphasis of this paper is comparing different techniques of choosing calibration samples such as randomly selected method, chemical data and also based on PCA. Since increasing the number of samples is usually time-consuming and costly, then in this study, the best sampling way -in available methods- was predicted for calibration models. In addition, the effect of sample size on the accuracy of the calibration and validation models was analyzed. Materials and Methods Two hundred and ten soil samples were collected from cultivated farm located in Avarzaman in Hamedan province, Iran. The crop rotation was mostly potato and wheat. Samples were collected from a depth of 20 cm above ground and passed through a 2 mm sieve and air dried at room temperature. Chemical analysis was performed in the soil science laboratory, faculty of agriculture engineering, Bu-ali Sina University, Hamadan, Iran. Two Spectrometer (AvaSpec-ULS 2048- UV-VIS and (FT-NIR100N were used to measure the spectral bands which cover the UV-Vis and NIR region (220-2200 nm. Each soil sample was uniformly tiled in a petri dish and was scanned 20 times. Then the pre-processing methods of multivariate scatter correction (MSC and base line correction (BC were applied on the raw signals using Unscrambler software. The samples were divided into two groups: one group for calibration 105 and the second group was used for validation. Each time, 15 samples were selected randomly and tested the accuracy of

  17. 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....

  18. The importance of protein in leaf selection of folivorous primates.

    Science.gov (United States)

    Ganzhorn, Joerg U; Arrigo-Nelson, Summer J; Carrai, Valentina; Chalise, Mukesh K; Donati, Giuseppe; Droescher, Iris; Eppley, Timothy M; Irwin, Mitchell T; Koch, Flávia; Koenig, Andreas; Kowalewski, Martin M; Mowry, Christopher B; Patel, Erik R; Pichon, Claire; Ralison, Jose; Reisdorff, Christoph; Simmen, Bruno; Stalenberg, Eleanor; Starrs, Danswell; Terboven, Juana; Wright, Patricia C; Foley, William J

    2017-04-01

    Protein limitation has been considered a key factor in hypotheses on the evolution of life history and animal communities, suggesting that animals should prioritize protein in their food choice. This contrasts with the limited support that food selection studies have provided for such a priority in nonhuman primates, particularly for folivores. Here, we suggest that this discrepancy can be resolved if folivores only need to select for high protein leaves when average protein concentration in the habitat is low. To test the prediction, we applied meta-analyses to analyze published and unpublished results of food selection for protein and fiber concentrations from 24 studies (some with multiple species) of folivorous primates. To counter potential methodological flaws, we differentiated between methods analyzing total nitrogen and soluble protein concentrations. We used a meta-analysis to test for the effect of protein on food selection by primates and found a significant effect of soluble protein concentrations, but a non-significant effect for total nitrogen. Furthermore, selection for soluble protein was reinforced in forests where protein was less available. Selection for low fiber content was significant but unrelated to the fiber concentrations in representative leaf samples of a given forest. There was no relationship (either negative or positive) between the concentration of protein and fiber in the food or in representative samples of leaves. Overall our study suggests that protein selection is influenced by the protein availability in the environment, explaining the sometimes contradictory results in previous studies on protein selection. Am. J. Primatol. 79:e22550, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  19. The Multi-Template Molecularly Imprinted Polymer Based on SBA-15 for Selective Separation and Determination of Panax notoginseng Saponins Simultaneously in Biological Samples

    Directory of Open Access Journals (Sweden)

    Chenghong Sun

    2017-11-01

    Full Text Available The feasible, reliable and selective multi-template molecularly imprinted polymers (MT-MIPs based on SBA-15 (SBA-15@MT-MIPs for the selective separation and determination of the trace level of ginsenoside Rb1 (Rb1, ginsenoside Rg1 (Rg1 and notoginsenoside R1 (R1 simultaneously from biological samples were developed. The polymers were constructed by SBA-15 as support, Rb1, Rg1, R1 as multi-template, acrylamide (AM as functional monomer and ethylene glycol dimethacrylate (EGDMA as cross-linker. The new synthetic SBA-15@MT-MIPs were satisfactorily applied to solid-phase extraction (SPE coupled with high performance liquid chromatography (HPLC for the separation and determination of trace Rb1, Rg1 and R1 in plasma samples. Under the optimized conditions, the limits of detection (LODs and quantitation (LOQs of the proposed method for Rb1, Rg1 and R1 were in the range of 0.63–0.75 ng·mL−1 and 2.1–2.5 ng·mL−1, respectively. The recoveries of R1, Rb1 and Rg1 were obtained between 93.4% and 104.3% with relative standard deviations (RSDs in the range of 3.3–4.2%. All results show that the obtained SBA-15@MT-MIPs could be a promising prospect for the practical application in the selective separation and enrichment of trace Panax notoginseng saponins (PNS in the biological samples.

  20. Gemcitabine: Selective cytotoxicity, induction of inflammation and effects on urothelial function

    Energy Technology Data Exchange (ETDEWEB)

    Farr, Stefanie E; Chess-Williams, Russ; McDermott, Catherine M, E-mail: camcderm@bond.edu.au

    2017-02-01

    Intravesical gemcitabine has recently been introduced for the treatment of superficial bladder cancer and has a favourable efficacy and toxicity profile in comparison to mitomycin c (MMC), the most commonly used chemotherapeutic agent. The aim of this study was to assess the cytotoxic potency of gemcitabine in comparison to MMC in urothelial cell lines derived from non-malignant (UROtsa) and malignant (RT4 and T24) tissues to assess selectivity. Cells were treated with gemcitabine or mitomycin C at concentrations up to the clinical doses for 1 or 2 h respectively (clinical duration). Treatment combined with hyperthermia was also examined. Cell viability, ROS formation, urothelial function (ATP, acetylcholine and PGE2 release) and secretion of inflammatory cytokines were assessed. Gemcitabine displayed a high cytotoxic selectivity for the two malignant cell lines (RT4, T24) compared to the non-malignant urothelial cells (UROtsa, proliferative and non-proliferative). In contrast, the cytotoxic effects of MMC were non-selective with equivalent potency in each of the cell lines. The cytotoxic effect of gemcitabine in the malignant cell lines was associated with an elevation in free radical formation and was significantly decreased in the presence of an equilibrative nucleoside transporter inhibitor. Transient changes in urothelial ATP and PGE{sub 2} release were observed, with significant increase in release of interleukin-6, interleukin-8 and interleukin-1β from urothelial cells treated with gemcitabine. The selectivity of gemcitabine for malignant urothelial cells may account for the less frequent adverse urological effects with comparison to other commonly used chemotherapeutic agents. - Highlights: • Intravesical gemcitabine has recently been introduced to treat bladder cancer. • Gemcitabine is selectively toxic for malignant urothelial cells. • Urothelial ATP, PGE{sub 2} and inflammatory cytokines were altered by gemcitabine. • Selectivity of gemcitabine

  1. Bolometric-Effect-Based Wavelength-Selective Photodetectors Using Sorted Single Chirality Carbon Nanotubes

    Science.gov (United States)

    Zhang, Suoming; Cai, Le; Wang, Tongyu; Shi, Rongmei; Miao, Jinshui; Wei, Li; Chen, Yuan; Sepúlveda, Nelson; Wang, Chuan

    2015-01-01

    This paper exploits the chirality-dependent optical properties of single-wall carbon nanotubes for applications in wavelength-selective photodetectors. We demonstrate that thin-film transistors made with networks of carbon nanotubes work effectively as light sensors under laser illumination. Such photoresponse was attributed to photothermal effect instead of photogenerated carriers and the conclusion is further supported by temperature measurements. Additionally, by using different types of carbon nanotubes, including a single chirality (9,8) nanotube, the devices exhibit wavelength-selective response, which coincides well with the absorption spectra of the corresponding carbon nanotubes. This is one of the first reports of controllable and wavelength-selective bolometric photoresponse in macroscale assemblies of chirality-sorted carbon nanotubes. The results presented here provide a viable route for achieving bolometric-effect-based photodetectors with programmable response spanning from visible to near-infrared by using carbon nanotubes with pre-selected chiralities. PMID:26643777

  2. New competitive dendrimer-based and highly selective immunosensor for determination of atrazine in environmental, feed and food samples: the importance of antibody selectivity for discrimination among related triazinic metabolites.

    Science.gov (United States)

    Giannetto, Marco; Umiltà, Eleonora; Careri, Maria

    2014-01-02

    A new voltammetric competitive immunosensor selective for atrazine, based on the immobilization of a conjugate atrazine-bovine serum albumine on a nanostructured gold substrate previously functionalized with poliamidoaminic dendrimers, was realized, characterized, and validated in different real samples of environmental and food concern. Response of the sensor was reliable, highly selective and suitable for the detection and quantification of atrazine at trace levels in complex matrices such as territorial waters, corn-cultivated soils, corn-containing poultry and bovine feeds and corn flakes for human use. Selectivity studies were focused on desethylatrazine, the principal metabolite generated by long-term microbiological degradation of atrazine, terbutylazine-2-hydroxy and simazine as potential interferents. The response of the developed immunosensor for atrazine was explored over the 10(-2)-10(3) ng mL(-1) range. Good sensitivity was proved, as limit of detection and limit of quantitation of 1.2 and 5 ng mL(-1), respectively, were estimated for atrazine. RSD values <5% over the entire explored range attested a good precision of the device. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Effects-Driven Participatory Design: Learning from Sampling Interruptions

    DEFF Research Database (Denmark)

    Brandrup, Morten; Østergaard, Kija Lin; Hertzum, Morten

    2017-01-01

    a sustained focus on pursued effects and uses the experience sampling method (ESM) to collect real-use feedback. To illustrate the use of the method we analyze a case that involves the organizational implementation of electronic whiteboards at a Danish hospital to support the clinicians’ intra...

  4. Radiation hazards evaluation for selected sand samples from Camburi beach, Vitoria, Espirito Santo, Brazil

    International Nuclear Information System (INIS)

    Barros, Livia F.; Pecequilo, Brigitte R.S.

    2013-01-01

    In this work, a single location at Camburi beach, known to be a naturally high background region, was studied. Radiation hazards indexes and annual effective dose were evaluated from the 226 Ra, 232 Th and 40 K sands activities concentrations. Sand samples were monthly collected during 2011, dried, sealed in standard 100 mL HPDE polyethylene flasks and measured by high resolution gamma spectrometry after a 4 weeks in-growth period. The 226 Ra concentration was determined from the weighted average concentrations of 214 Pb and 214 Bi. The 232 Th concentration was determined from the weighted average concentrations of 228 Ac, 212 Pb and 212 Bi and the 4 0K from its single gamma transition. The results, considering samples gamma-rays self-attenuation, show activities concentrations in the range from 6 Bq kg -1 to 39 Bq kg -1 for 226 Ra, 13 Bq kg -1 to 161 Bq kg -1 for 232 Th, and 7 Bq kg -1 to 65 Bq kg -1 for 40 K. The radium equivalent activity for the studied samples ranged from 26 Bq kg -1 to 274 Bq kg - '1. The external and internal hazard indexes varied, respectively, from 0.07 to 0.74 and from 0.09 to 0.85. The annual effective dose values laid from 0.07 mSv.y -1 to 0.72 mSv.y - '1. All values obtained in this work are below the radiological protection recommended limits. (author)

  5. Selective extraction of chromium(VI) using a leaching procedure with sodium carbonate from some plant leaves, soil and sediment samples

    Energy Technology Data Exchange (ETDEWEB)

    Elci, Latif, E-mail: elci@pamukkale.edu.tr [Department of Chemistry, Pamukkale University, 20017 Denizli (Turkey); Divrikli, Umit; Akdogan, Abdullah; Hol, Aysen; Cetin, Ayse [Department of Chemistry, Pamukkale University, 20017 Denizli (Turkey); Soylak, Mustafa [Department of Chemistry, Erciyes University, 38039 Kayseri (Turkey)

    2010-01-15

    Speciation of chromium in some plant leaves, soil and sediment samples was carried out by selective leaching of Cr(VI) using a sodium carbonate leaching procedure. Total chromium from the samples was extracted using aqua regia and oxidative acid digestion, respectively. The concentrations of chromium species in the extracts were determined using by graphite furnace atomic absorption spectrometry (GFAAS). Uncoated graphite furnace tubes were used as an atomizer. Due to the presence of relatively high amounts of Na{sub 2}CO{sub 3} in the resulting samples, the possible influences of Na{sub 2}CO{sub 3} on the absorbance signals were checked. There is no interference of Na{sub 2}CO{sub 3} on the chromium absorbance up to 0.1 mol L{sup -1} Na{sub 2}CO{sub 3}. A limit of detection (LOD) for determination of Cr(VI) in 0.1 Na{sub 2}CO{sub 3} solution by GFAAS was found to be 0.93 {mu}g L{sup -1}. The procedure was applied to environmental samples. The relative standard deviation, R.S.D. as precision for 10 replicate measurements of 20 {mu} L{sup -1} Cr in processed soil sample was 4.2%.

  6. Selective extraction of chromium(VI) using a leaching procedure with sodium carbonate from some plant leaves, soil and sediment samples.

    Science.gov (United States)

    Elci, Latif; Divrikli, Umit; Akdogan, Abdullah; Hol, Aysen; Cetin, Ayse; Soylak, Mustafa

    2010-01-15

    Speciation of chromium in some plant leaves, soil and sediment samples was carried out by selective leaching of Cr(VI) using a sodium carbonate leaching procedure. Total chromium from the samples was extracted using aqua regia and oxidative acid digestion, respectively. The concentrations of chromium species in the extracts were determined using by graphite furnace atomic absorption spectrometry (GFAAS). Uncoated graphite furnace tubes were used as an atomizer. Due to the presence of relatively high amounts of Na(2)CO(3) in the resulting samples, the possible influences of Na(2)CO(3) on the absorbance signals were checked. There is no interference of Na(2)CO(3) on the chromium absorbance up to 0.1 mol L(-1) Na(2)CO(3). A limit of detection (LOD) for determination of Cr(VI) in 0.1 Na(2)CO(3) solution by GFAAS was found to be 0.93 microg L(-1). The procedure was applied to environmental samples. The relative standard deviation, R.S.D. as precision for 10 replicate measurements of 20 microL(-1) Cr in processed soil sample was 4.2%.

  7. Generalizability of causal inference in observational studies under retrospective convenience sampling.

    Science.gov (United States)

    Hu, Zonghui; Qin, Jing

    2018-05-20

    Many observational studies adopt what we call retrospective convenience sampling (RCS). With the sample size in each arm prespecified, RCS randomly selects subjects from the treatment-inclined subpopulation into the treatment arm and those from the control-inclined into the control arm. Samples in each arm are representative of the respective subpopulation, but the proportion of the 2 subpopulations is usually not preserved in the sample data. We show in this work that, under RCS, existing causal effect estimators actually estimate the treatment effect over the sample population instead of the underlying study population. We investigate how to correct existing methods for consistent estimation of the treatment effect over the underlying population. Although RCS is adopted in medical studies for ethical and cost-effective purposes, it also has a big advantage for statistical inference: When the tendency to receive treatment is low in a study population, treatment effect estimators under RCS, with proper correction, are more efficient than their parallels under random sampling. These properties are investigated both theoretically and through numerical demonstration. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

  8. A homogeneous sample of binary galaxies: Basic observational properties

    Science.gov (United States)

    Karachentsev, I. D.

    1990-01-01

    A survey of optical characteristics for 585 binary systems, satisfying a condition of apparent isolation on the sky, is presented. Influences of various selection effects distorting the average parameters of the sample are noted. The pair components display mutual similarity over all the global properties: luminosity, diameter, morphological type, mass-to-luminosity ratio, angular momentum etc., which is not due only to selection effects. The observed correlations must be caused by common origin of pair members. Some features (nuclear activity, color index) could acquire similarity during synchronous evolution of double galaxies. Despite the observed isolation, the sample of double systems is seriously contaminated by accidental pairs, and also by members of groups and clusters. After removing false pairs estimates of orbital mass-to-luminosity ratio range from 0 to 30 f(solar), with the mean value (7.8 plus or minus 0.7) f(solar). Binary galaxies possess nearly circular orbits with a typical eccentrity e = 0.25, probably resulting from evolutionary selection driven by component mergers under dynamical friction. The double-galaxy population with space abundance 0.12 plus or minus 0.02 and characteristic merger timescale 0.2 H(exp -1) may significantly influence the rate of dynamical evolution of galaxies.

  9. Determination of selected metals in coal samples from Lafia-Obi and ...

    African Journals Online (AJOL)

    coal samples were determined using atomic absorption spectroscopy (AAS). All the samples have comparable chromium and copper contents, while iron, aluminum, magnesium and potassium content vary to some extent. Metals concentrations in both Lafia-Obi and Chikila coal samples are within the limits allowed by the ...

  10. Getting DNA copy numbers without control samples

    Directory of Open Access Journals (Sweden)

    Ortiz-Estevez Maria

    2012-08-01

    Full Text Available Abstract Background The selection of the reference to scale the data in a copy number analysis has paramount importance to achieve accurate estimates. Usually this reference is generated using control samples included in the study. However, these control samples are not always available and in these cases, an artificial reference must be created. A proper generation of this signal is crucial in terms of both noise and bias. We propose NSA (Normality Search Algorithm, a scaling method that works with and without control samples. It is based on the assumption that genomic regions enriched in SNPs with identical copy numbers in both alleles are likely to be normal. These normal regions are predicted for each sample individually and used to calculate the final reference signal. NSA can be applied to any CN data regardless the microarray technology and preprocessing method. It also finds an optimal weighting of the samples minimizing possible batch effects. Results Five human datasets (a subset of HapMap samples, Glioblastoma Multiforme (GBM, Ovarian, Prostate and Lung Cancer experiments have been analyzed. It is shown that using only tumoral samples, NSA is able to remove the bias in the copy number estimation, to reduce the noise and therefore, to increase the ability to detect copy number aberrations (CNAs. These improvements allow NSA to also detect recurrent aberrations more accurately than other state of the art methods. Conclusions NSA provides a robust and accurate reference for scaling probe signals data to CN values without the need of control samples. It minimizes the problems of bias, noise and batch effects in the estimation of CNs. Therefore, NSA scaling approach helps to better detect recurrent CNAs than current methods. The automatic selection of references makes it useful to perform bulk analysis of many GEO or ArrayExpress experiments without the need of developing a parser to find the normal samples or possible batches within the

  11. Task-selective memory effects for successfully implemented encoding strategies.

    Directory of Open Access Journals (Sweden)

    Eric D Leshikar

    Full Text Available Previous behavioral evidence suggests that instructed strategy use benefits associative memory formation in paired associate tasks. Two such effective encoding strategies--visual imagery and sentence generation--facilitate memory through the production of different types of mediators (e.g., mental images and sentences. Neuroimaging evidence suggests that regions of the brain support memory reflecting the mental operations engaged at the time of study. That work, however, has not taken into account self-reported encoding task success (i.e., whether participants successfully generated a mediator. It is unknown, therefore, whether task-selective memory effects specific to each strategy might be found when encoding strategies are successfully implemented. In this experiment, participants studied pairs of abstract nouns under either visual imagery or sentence generation encoding instructions. At the time of study, participants reported their success at generating a mediator. Outside of the scanner, participants further reported the quality of the generated mediator (e.g., images, sentences for each word pair. We observed task-selective memory effects for visual imagery in the left middle occipital gyrus, the left precuneus, and the lingual gyrus. No such task-selective effects were observed for sentence generation. Intriguingly, activity at the time of study in the left precuneus was modulated by the self-reported quality (vividness of the generated mental images with greater activity for trials given higher ratings of quality. These data suggest that regions of the brain support memory in accord with the encoding operations engaged at the time of study.

  12. Sampling Operations on Big Data

    Science.gov (United States)

    2015-11-29

    gories. These include edge sampling methods where edges are selected by a predetermined criteria; snowball sampling methods where algorithms start... Sampling Operations on Big Data Vijay Gadepally, Taylor Herr, Luke Johnson, Lauren Milechin, Maja Milosavljevic, Benjamin A. Miller Lincoln...process and disseminate information for discovery and exploration under real-time constraints. Common signal processing operations such as sampling and

  13. Tomographic imaging of 12 fracture samples selected from Olkiluoto deep drillholes

    International Nuclear Information System (INIS)

    Kuva, J.; Voutilainen, M.; Timonen, J.; Aaltonen, I.

    2010-06-01

    Rock samples from Olkiluoto were imaged with X-ray tomography to analyze distributions of mineral components and alteration of rock around different fracture types. Twelve samples were analyzed, which contained three types of fractures, and each sample was scanned with two different resolutions. Three dimensional reconstructions of the samples with four or five distinct mineral components displayed changes in the mineral distribution around previously water conducting fractures, which extended to a depth of several millimeters away from fracture surfaces. In addition, structure of fracture filling minerals is depicted. (orig.)

  14. Effects of blood sample handling procedures on measurable inflammatory markers in plasma, serum and dried blood spot samples

    DEFF Research Database (Denmark)

    Skogstrand, K.; Thorsen, P.; Vogel, I.

    2008-01-01

    of whole blood samples at low temperatures and rapid isolation of plasma and serum. Effects of different handling procedures for all markers studied are given. DBSS proved to be a robust and convenient way to handle samples for immunoassay analysis of inflammatory markers in whole blood Udgivelsesdato......The interests in monitoring inflammation by immunoassay determination of blood inflammatory markers call for information on the stability of these markers in relation to the handling of blood samples. The increasing use of stored biobank samples for such ventures that may have been collected...... and stored for other purposes, justifies the study hereof. Blood samples were stored for 0, 4, 24, and 48 h at 4 degrees C, room temperature (RT), and at 35 degrees C, respectively, before they were separated into serum or plasma and frozen. Dried blood spot samples (DBSS) were stored for 0, 1, 2, 3, 7...

  15. Automatic Samples Selection Using Histogram of Oriented Gradients (HOG Feature Distance

    Directory of Open Access Journals (Sweden)

    Inzar Salfikar

    2018-01-01

    Full Text Available Finding victims at a disaster site is the primary goal of Search-and-Rescue (SAR operations. Many technologies created from research for searching disaster victims through aerial imaging. but, most of them are difficult to detect victims at tsunami disaster sites with victims and backgrounds which are look similar. This research collects post-tsunami aerial imaging data from the internet to builds dataset and model for detecting tsunami disaster victims. Datasets are built based on distance differences from features every sample using Histogram-of-Oriented-Gradient (HOG method. We use the longest distance to collect samples from photo to generate victim and non-victim samples. We claim steps to collect samples by measuring HOG feature distance from all samples. the longest distance between samples will take as a candidate to build the dataset, then classify victim (positives and non-victim (negatives samples manually. The dataset of tsunami disaster victims was re-analyzed using cross-validation Leave-One-Out (LOO with Support-Vector-Machine (SVM method. The experimental results show the performance of two test photos with 61.70% precision, 77.60% accuracy, 74.36% recall and f-measure 67.44% to distinguish victim (positives and non-victim (negatives.

  16. Measurement of peak impact loads differ between accelerometers - Effects of system operating range and sampling rate.

    Science.gov (United States)

    Ziebart, Christina; Giangregorio, Lora M; Gibbs, Jenna C; Levine, Iris C; Tung, James; Laing, Andrew C

    2017-06-14

    A wide variety of accelerometer systems, with differing sensor characteristics, are used to detect impact loading during physical activities. The study examined the effects of system characteristics on measured peak impact loading during a variety of activities by comparing outputs from three separate accelerometer systems, and by assessing the influence of simulated reductions in operating range and sampling rate. Twelve healthy young adults performed seven tasks (vertical jump, box drop, heel drop, and bilateral single leg and lateral jumps) while simultaneously wearing three tri-axial accelerometers including a criterion standard laboratory-grade unit (Endevco 7267A) and two systems primarily used for activity-monitoring (ActiGraph GT3X+, GCDC X6-2mini). Peak acceleration (gmax) was compared across accelerometers, and errors resulting from down-sampling (from 640 to 100Hz) and range-limiting (to ±6g) the criterion standard output were characterized. The Actigraph activity-monitoring accelerometer underestimated gmax by an average of 30.2%; underestimation by the X6-2mini was not significant. Underestimation error was greater for tasks with greater impact magnitudes. gmax was underestimated when the criterion standard signal was down-sampled (by an average of 11%), range limited (by 11%), and by combined down-sampling and range-limiting (by 18%). These effects explained 89% of the variance in gmax error for the Actigraph system. This study illustrates that both the type and intensity of activity should be considered when selecting an accelerometer for characterizing impact events. In addition, caution may be warranted when comparing impact magnitudes from studies that use different accelerometers, and when comparing accelerometer outputs to osteogenic impact thresholds proposed in literature. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  17. Effects of selected bioactive food compounds on human white adipocyte function

    DEFF Research Database (Denmark)

    Björk, Christel; Wilhelm, Uta; Mandrup, Susanne

    2016-01-01

    BACKGROUND: Previous studies suggest that intake of specific bioactive compounds may have beneficial clinical effects on adipose tissue partly due to their anti-inflammatory and insulin-sensitizing properties. With the overall aim to contribute to better understanding of the mechanisms of selecte...... uptake albeit only with the combination of DHA and AC. Taken together, our results may link the reported health benefits of the selected bioactives on metabolic disorders such as insulin resistance, hypertension and dyslipidemia to effects on white adipocytes....

  18. Meta-analysis of age and skill effects on recalling chess positions and selecting the best move.

    Science.gov (United States)

    Moxley, Jerad H; Charness, Neil

    2013-10-01

    A meta-analysis was conducted of studies that measured the effects of both age and skill in chess on the tasks of selecting the best move for chess positions (the best move task) as well as recalling chess game positions (the recall task). Despite a small sample of studies, we demonstrated that there are age and skill effects on both tasks: age being negatively associated with performance on both tasks and skill being positively associated with performance on both tasks. On the best move task, we found that skill was the dominant effect, while on the recall task, skill and age were approximately equally strong effects. We also found that skill was best measured by the best move task. In the case of the best move task, this result is consistent with the argument that it accurately replicates expert performance (Ericsson & Smith, 1991). Results for the recall task argue that this task captures effects related to skill, but also effects likely due to a general aging process. Implications for our understanding of aging in skilled domains are also discussed.

  19. Neutron moderation in a bulk sample and its effects on PGNAA setup geometry

    International Nuclear Information System (INIS)

    Al-Jarallah, M.I.; Naqvi, A.A.; Fazal-ur-Rehman,; Maselehuddin, M.; Abu-Jarad, F.; Raashid, M.

    2003-01-01

    In a prompt gamma ray neutron activation analysis (PGNAA) setup, the neutron moderation in the bulk sample also plays a key role. This can even dominate the thermalization effects of the external moderator in some cases. In order to study the neutron moderation effect in the bulk sample, moderators with two different sizes of the sample were tested at the King Fahd University of Petroleum and Minerals (KFUPM) PGNAA facility. In these tests, the thermal neutron relative intensity and prompt gamma ray yield from the two moderators were measured using nuclear track detectors (NTDs) and NaI detector, respectively. As predicted by Monte Carlo simulations, the measured intensity of thermal neutron inside the large sample cavity due to the external moderator was smaller than that from the smaller sample cavity. Due to its larger size, additional thermalization of neutrons will take place in the larger sample. In spite of smaller thermal neutron yield from the external moderator at the large sample location, higher yield of the prompt gamma ray was observed as compared to that from the smaller sample. This confirms the significance of neutron moderation effects in the bulk sample and can thereby affect the PGNAA geometry size. This allows larger samples in conjunction with smaller moderators in the PGNAA setup

  20. Neutron moderation in a bulk sample and its effects on PGNAA setup geometry

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jarallah, M.I. E-mail: mibrahim@kfupm.edu.sa; Naqvi, A.A.; Fazal-ur-Rehman,; Maselehuddin, M.; Abu-Jarad, F.; Raashid, M

    2003-06-01

    In a prompt gamma ray neutron activation analysis (PGNAA) setup, the neutron moderation in the bulk sample also plays a key role. This can even dominate the thermalization effects of the external moderator in some cases. In order to study the neutron moderation effect in the bulk sample, moderators with two different sizes of the sample were tested at the King Fahd University of Petroleum and Minerals (KFUPM) PGNAA facility. In these tests, the thermal neutron relative intensity and prompt gamma ray yield from the two moderators were measured using nuclear track detectors (NTDs) and NaI detector, respectively. As predicted by Monte Carlo simulations, the measured intensity of thermal neutron inside the large sample cavity due to the external moderator was smaller than that from the smaller sample cavity. Due to its larger size, additional thermalization of neutrons will take place in the larger sample. In spite of smaller thermal neutron yield from the external moderator at the large sample location, higher yield of the prompt gamma ray was observed as compared to that from the smaller sample. This confirms the significance of neutron moderation effects in the bulk sample and can thereby affect the PGNAA geometry size. This allows larger samples in conjunction with smaller moderators in the PGNAA setup.

  1. Fatigue behavior of thin-walled grade 2 titanium samples processed by selective laser melting. Application to life prediction of porous titanium implants.

    Science.gov (United States)

    Lipinski, P; Barbas, A; Bonnet, A-S

    2013-12-01

    Because of its biocompatibility and high mechanical properties, the commercially pure grade 2 titanium (CPG2Ti) is largely used for fabrication of patient specific implants or hard tissue substitutes with complex shape. To avoid the stress-shielding and help their colonization by bone, prostheses with a controlled porosity are designed. The selective laser melting (SLM) is well adapted to manufacture such geometrically complicated structures constituted by struts with rough surfaces and relatively small diameters. Few studies were dedicated to characterize the fatigue properties of SLM processed samples and bulk parts. They followed conventional or standard protocols. The fatigue behavior of standard samples is very different from the one of porous raw structures. In this study, the SLM made "as built" (AB) and "heat treated" (HT) tubular samples were tested in fatigue. Wöhler curves were determined in both cases. The obtained endurance limits were equal to σD(AB)=74.5MPa and σD(HT)=65.7MPa, respectively. The heat treatment worsened the endurance limit by relaxation of negative residual stresses measured on the external surface of the samples. Modified Goodman diagram was established for raw specimens. Porous samples, based on the pattern developed by Barbas et al. (2012), were manufactured by SLM. Fatigue tests and finite element simulations performed on these samples enabled the determination of a simple rule of fatigue assessment. The method based on the stress gradient appeared as the best approach to take into account the notch influence on the fatigue life of CPG2Ti structures with a controlled porosity. The direction dependent apparent fatigue strength was found. A criterion based on the effective, or global, nominal stress was proposed taking into account the anisotropy of the porous structures. Thanks to this criterion, the usual calculation methods can be used to design bone substitutes, without a precise modelling of their internal fine porosity.

  2. Effects of task-irrelevant grouping on visual selection in partial report

    DEFF Research Database (Denmark)

    Lunau, Rasmus; Habekost, Thomas

    2017-01-01

    and the selection criterion was luminance. This effect was accompanied by impaired selectivity in unsorted-color trials. Overall, the results suggest that the benefit of task-irrelevant color grouping of targets is contingent on the processing locus of the selection criterion....... the color of the elements in these trials. In the sorted-color condition, the color of the display elements was arranged according to the selection criterion, and in the unsorted-color condition, colors were randomly assigned. The distractor cost was inferred by subtracting performance in partial......-report trials from performance in a control condition that had no distractors in the display. Across five experiments, we manipulated trial order, selection criterion, and exposure duration, and found that attentional selectivity was improved in sorted-color trials when the exposure duration was 200 ms...

  3. Handling missing data in ranked set sampling

    CERN Document Server

    Bouza-Herrera, Carlos N

    2013-01-01

    The existence of missing observations is a very important aspect to be considered in the application of survey sampling, for example. In human populations they may be caused by a refusal of some interviewees to give the true value for the variable of interest. Traditionally, simple random sampling is used to select samples. Most statistical models are supported by the use of samples selected by means of this design. In recent decades, an alternative design has started being used, which, in many cases, shows an improvement in terms of accuracy compared with traditional sampling. It is called R

  4. 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 ...

  5. Energetic benefits and adaptations in mammalian limbs: Scale effects and selective pressures.

    Science.gov (United States)

    Kilbourne, Brandon M; Hoffman, Louwrens C

    2015-06-01

    Differences in limb size and shape are fundamental to mammalian morphological diversity; however, their relevance to locomotor costs has long been subject to debate. In particular, it remains unknown if scale effects in whole limb morphology could partially underlie decreasing mass-specific locomotor costs with increasing limb length. Whole fore- and hindlimb inertial properties reflecting limb size and shape-moment of inertia (MOI), mass, mass distribution, and natural frequency-were regressed against limb length for 44 species of quadrupedal mammals. Limb mass, MOI, and center of mass position are negatively allometric, having a strong potential for lowering mass-specific locomotor costs in large terrestrial mammals. Negative allometry of limb MOI results in a 40% reduction in MOI relative to isometry's prediction for our largest sampled taxa. However, fitting regression residuals to adaptive diversification models reveals that codiversification of limb mass, limb length, and body mass likely results from selection for differing locomotor modes of running, climbing, digging, and swimming. The observed allometric scaling does not result from selection for energetically beneficial whole limb morphology with increasing size. Instead, our data suggest that it is a consequence of differing morphological adaptations and body size distributions among quadrupedal mammals, highlighting the role of differing limb functions in mammalian evolution. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  6. 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

  7. Effect of Selected Light Spectra on the Growth of Chlorella spp ...

    African Journals Online (AJOL)

    The possibility for simultaneous production of chemical and electrical energies from a single microalgae cultivation plant is opening a new chapter in the efficient use of resources to maximize biomass productivity. In the current study, the effect of selected monochromatic lights (blue, red and pink) from spectrally selective ...

  8. The effectiveness of cooling conditions on temperature of canine EDTA whole blood samples.

    Science.gov (United States)

    Tobias, Karen M; Serrano, Leslie; Sun, Xiaocun; Flatland, Bente

    2016-01-01

    Preanalytic factors such as time and temperature can have significant effects on laboratory test results. For example, ammonium concentration will increase 31% in blood samples stored at room temperature for 30 min before centrifugation. To reduce preanalytic error, blood samples may be placed in precooled tubes and chilled on ice or in ice water baths; however, the effectiveness of these modalities in cooling blood samples has not been formally evaluated. The purpose of this study was to evaluate the effectiveness of various cooling modalities on reducing temperature of EDTA whole blood samples. Pooled samples of canine EDTA whole blood were divided into two aliquots. Saline was added to one aliquot to produce a packed cell volume (PCV) of 40% and to the second aliquot to produce a PCV of 20% (simulated anemia). Thirty samples from each aliquot were warmed to 37.7 °C and cooled in 2 ml allotments under one of three conditions: in ice, in ice after transfer to a precooled tube, or in an ice water bath. Temperature of each sample was recorded at one minute intervals for 15 min. Within treatment conditions, sample PCV had no significant effect on cooling. Cooling in ice water was significantly faster than cooling in ice only or transferring the sample to a precooled tube and cooling it on ice. Mean temperature of samples cooled in ice water was significantly lower at 15 min than mean temperatures of those cooled in ice, whether or not the tube was precooled. By 4 min, samples cooled in an ice water bath had reached mean temperatures less than 4 °C (refrigeration temperature), while samples cooled in other conditions remained above 4.0 °C for at least 11 min. For samples with a PCV of 40%, precooling the tube had no significant effect on rate of cooling on ice. For samples with a PCV of 20%, transfer to a precooled tube resulted in a significantly faster rate of cooling than direct placement of the warmed tube onto ice. Canine EDTA whole blood samples cool most

  9. Effects of Divergent Selection for Fear of Humans on Behaviour in Red Junglefowl.

    Directory of Open Access Journals (Sweden)

    Beatrix Agnvall

    Full Text Available Domestication has caused a range of similar phenotypic changes across taxa, relating to physiology, morphology and behaviour. It has been suggested that this recurring domesticated phenotype may be a result of correlated responses to a central trait, namely increased tameness. We selected Red Junglefowl, the ancestors of domesticated chickens, during five generations for reduced fear of humans. This caused a marked and significant response in tameness, and previous studies have found correlated effects on growth, metabolism, reproduction, and some behaviour not directly selected for. Here, we report the results from a series of behavioural tests carried out on the initial parental generation (P0 and the fifth selected generation (S5, focusing on behaviour not functionally related to tameness, in order to study any correlated effects. Birds were tested for fear of humans, social reinstatement tendency, open field behaviour at two different ages, foraging/exploration, response to a simulated aerial predator attack and tonic immobility. In S5, there were no effects of selection on foraging/exploration or tonic immobility, while in the social reinstatement and open field tests there were significant interactions between selection and sex. In the aerial predator test, there were significant main effects of selection, indicating that fear of humans may represent a general wariness towards predators. In conclusion, we found only small correlated effects on behaviours not related to the tameness trait selected for, in spite of them showing high genetic correlations to fear of humans in a previous study on the same population. This suggests that species-specific behaviour is generally resilient to changes during domestication.

  10. Effects of Divergent Selection for Fear of Humans on Behaviour in Red Junglefowl

    Science.gov (United States)

    Agnvall, Beatrix; Jensen, Per

    2016-01-01

    Domestication has caused a range of similar phenotypic changes across taxa, relating to physiology, morphology and behaviour. It has been suggested that this recurring domesticated phenotype may be a result of correlated responses to a central trait, namely increased tameness. We selected Red Junglefowl, the ancestors of domesticated chickens, during five generations for reduced fear of humans. This caused a marked and significant response in tameness, and previous studies have found correlated effects on growth, metabolism, reproduction, and some behaviour not directly selected for. Here, we report the results from a series of behavioural tests carried out on the initial parental generation (P0) and the fifth selected generation (S5), focusing on behaviour not functionally related to tameness, in order to study any correlated effects. Birds were tested for fear of humans, social reinstatement tendency, open field behaviour at two different ages, foraging/exploration, response to a simulated aerial predator attack and tonic immobility. In S5, there were no effects of selection on foraging/exploration or tonic immobility, while in the social reinstatement and open field tests there were significant interactions between selection and sex. In the aerial predator test, there were significant main effects of selection, indicating that fear of humans may represent a general wariness towards predators. In conclusion, we found only small correlated effects on behaviours not related to the tameness trait selected for, in spite of them showing high genetic correlations to fear of humans in a previous study on the same population. This suggests that species-specific behaviour is generally resilient to changes during domestication. PMID:27851792

  11. Geochemical and mineralogical study of selected weathered samples from Olkiluoto site

    International Nuclear Information System (INIS)

    Lindberg, A.

    2009-02-01

    Optical microscopy, chemical analyses and X-ray diffraction method were used to study the influence of weathering from 11 drill core samples from shallow depths (< 25 m). The samples, 4 to 22 cm in length were drilled from Olkiluoto study site, Eurajoki, and they represent the common rock types of local bedrock: mica gneiss, tonalitic and granodioritic gneiss. Two of the samples were macroscopically unweathered and 9 of them were remarkably altered. The alteration was shown as porosity, the abundance of chlorite instead of biotite and pink, unclear feldspars. Many samples also contained red-brown hematite and fractures, some of them coated with secondary minerals, even clay. Microscopically the most visible feature of weathering was the total alteration of plagioclase and cordierite to sericite. In many samples also biotite was richly altered to chlorite and opaque minerals. Microfractures were common and they were filled by hematite, kaolinite and fine-grained muscovite (sericite). Hematite was, in some cases, also largely replacing the weathered minerals, feldspars and cordierite. Chemical alteration was not clear, because the alteration of main minerals have produced secondary minerals with almost the same chemical composition without any reasonable depleting or enrichment of certain elements. X-ray diffraction determination of samples proved, that often plagioclase was replaced by mica and biotite by chlorite. In some cases the samples contained products of chemical weathering, kaolinite and smectite. (orig.)

  12. Instance selection in digital soil mapping: a study case in Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Elvio Giasson

    2015-09-01

    Full Text Available A critical issue in digital soil mapping (DSM is the selection of data sampling method for model training. One emerging approach applies instance selection to reduce the size of the dataset by drawing only relevant samples in order to obtain a representative subset that is still large enough to preserve relevant information, but small enough to be easily handled by learning algorithms. Although there are suggestions to distribute data sampling as a function of the soil map unit (MU boundaries location, there are still contradictions among research recommendations for locating samples either closer or more distant from soil MU boundaries. A study was conducted to evaluate instance selection methods based on spatially-explicit data collection using location in relation to soil MU boundaries as the main criterion. Decision tree analysis was performed for modeling digital soil class mapping using two different sampling schemes: a selecting sampling points located outside buffers near soil MU boundaries, and b selecting sampling points located within buffers near soil MU boundaries. Data was prepared for generating classification trees to include only data points located within or outside buffers with widths of 60, 120, 240, 360, 480, and 600m near MU boundaries. Instance selection methods using both spatial selection of methods was effective for reduced size of the dataset used for calibrating classification tree models, but failed to provide advantages to digital soil mapping because of potential reduction in the accuracy of classification tree models.

  13. Peer Effects on Obesity in a Sample of European Children

    DEFF Research Database (Denmark)

    Gwozdz, Wencke; Sousa-Poza, Alfonso; Reisch, Lucia A.

    2015-01-01

    This study analyzes peer effects on childhood obesity using data from the first two waves of the IDEFICS study, which applies several anthropometric and other measures of fatness to approximately 14,000 children aged two to nine participating in both waves in 16 regions of eight European countries....... Peers are defined as same-sex children in the same school and age group. The results show that peer effects do exist in this European sample but that they differ among both regions and different fatness measures. Peer effects are larger in Spain, Italy, and Cyprus – the more collectivist regions in our...... sample – while waist circumference generally gives rise to larger peer effects than BMI. We also provide evidence that parental misperceptions of their own children's weight goes hand in hand with fatter peer groups, supporting the notion that in making such assessments, parents compare their children...

  14. Effects of selected coping strategies on impediment oriented ...

    African Journals Online (AJOL)

    The study was carried out to determine the effects of selected coping strategies on the impediment oriented academic stress of the visually impaired pupils in Oji- River School for the Blind, Enugu State. The study is a quasi-Experimental design involving two treatment groups and one control group. Twenty visually impaired ...

  15. Effects of dance therapy on the selected hematological and rheological indicators in older women.

    Science.gov (United States)

    Filar-Mierzwa, Katarzyna; Marchewka, Anna; Bac, Aneta; Kulis, Aleksandra; Dąbrowski, Zbigniew; Teległów, Aneta

    2017-01-01

    The aim of this study was to analyze the effects of dance therapy on selected hematological and rheological indicators in older women. The study included 30 women (aged 71.8±7.4), and the control group comprised of 10 women of corresponding age. Women from the experimental group were subjected to a five-month dance therapy program (three 45-minute sessions per week); women from the control group were not involved in any regular physical activity. Blood samples from all the women were examined for hematological, rheological, and biochemical parameters prior to the study and five months thereafter. The dance therapy program was reflected by a significant improvement of erythrocyte count and hematocrit. Furthermore, the dance therapy resulted in a significant increase in the plasma viscosity, while no significant changes in glucose and fibrinogen levels were noted. Dance therapy modulates selected hematological parameters of older women; it leads to increase in erythrocyte count and hematocrit level. Dance therapy is reflected by higher plasma viscosity. Concentrations of fibrinogen and glucose are not affected by the dance therapy in older women, suggesting maintenance of homeostasis. Those findings advocate implementation of dance therapy programs in older women.

  16. Methodology Series Module 5: Sampling Strategies.

    Science.gov (United States)

    Setia, Maninder Singh

    2016-01-01

    Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ' Sampling Method'. There are essentially two types of sampling methods: 1) probability sampling - based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling - based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample) is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term ' random sample' when the researcher has used convenience sample). The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the ' generalizability' of these results. In such a scenario, the researcher may want to use ' purposive sampling' for the study.

  17. Methodology series module 5: Sampling strategies

    Directory of Open Access Journals (Sweden)

    Maninder Singh Setia

    2016-01-01

    Full Text Available Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the 'Sampling Method'. There are essentially two types of sampling methods: 1 probability sampling – based on chance events (such as random numbers, flipping a coin etc.; and 2 non-probability sampling – based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term 'random sample' when the researcher has used convenience sample. The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the 'generalizability' of these results. In such a scenario, the researcher may want to use 'purposive sampling' for the study.

  18. Plant selection and soil legacy enhance long-term biodiversity effects.

    Science.gov (United States)

    Zuppinger-Dingley, Debra; Flynn, Dan F B; De Deyn, Gerlinde B; Petermann, Jana S; Schmid, Bernhard

    2016-04-01

    Plant-plant and plant-soil interactions can help maintain plant diversity and ecosystem functions. Changes in these interactions may underlie experimentally observed increases in biodiversity effects over time via the selection of genotypes adapted to low or high plant diversity. Little is known, however, about such community-history effects and particularly the role of plant-soil interactions in this process. Soil-legacy effects may occur if co-evolved interactions with soil communities either positively or negatively modify plant biodiversity effects. We tested how plant selection and soil legacy influence biodiversity effects on productivity, and whether such effects increase the resistance of the communities to invasion by weeds. We used two plant selection treatments: parental plants growing in monoculture or in mixture over 8 yr in a grassland biodiversity experiment in the field, which we term monoculture types and mixture types. The two soil-legacy treatments used in this study were neutral soil inoculated with live or sterilized soil inocula collected from the same plots in the biodiversity experiment. For each of the four factorial combinations, seedlings of eight species were grown in monocultures or four-species mixtures in pots in an experimental garden over 15 weeks. Soil legacy (live inoculum) strongly increased biodiversity complementarity effects for communities of mixture types, and to a significantly weaker extent for communities of monoculture types. This may be attributed to negative plant-soil feedbacks suffered by mixture types in monocultures, whereas monoculture types had positive plant-soil feedbacks, in both monocultures and mixtures. Monocultures of mixture types were most strongly invaded by weeds, presumably due to increased pathogen susceptibility, reduced biomass, and altered plant-soil interactions of mixture types. These results show that biodiversity effects in experimental grassland communities can be modified by the evolution of

  19. A Multiwavelength Study of a Sample of 70 μm Selected Galaxies in the COSMOS Field : I. Spectral Energy Distributions and Luminosities

    NARCIS (Netherlands)

    Kartaltepe, Jeyhan S.; Sanders, D. B.; Le Floc'h, E.; Frayer, D. T.; Aussel, H.; Arnouts, S.; Ilbert, O.; Salvato, M.; Scoville, N. Z.; Surace, J.; Yan, L.; Brusa, M.; Capak, P.; Caputi, K.; Carollo, C. M.; Civano, F.; Elvis, M.; Faure, C.; Hasinger, G.; Koekemoer, A. M.; Lee, N.; Lilly, S.; Liu, C. T.; McCracken, H. J.; Schinnerer, E.; Smolčić, V.; Taniguchi, Y.; Thompson, D. J.; Trump, J.

    We present a large robust sample of 1503 reliable and unconfused 70 μm selected sources from the multiwavelength data set of the Cosmic Evolution Survey. Using the Spitzer IRAC and MIPS photometry, we estimate the total infrared (IR) luminosity, L IR (8-1000 μm), by finding the best-fit template

  20. Sequential effects in pigeon delayed matching-to-sample performance.

    Science.gov (United States)

    Roitblat, H L; Scopatz, R A

    1983-04-01

    Pigeons were tested in a three-alternative delayed matching-to-sample task in which second-choices were permitted following first-choice errors. Sequences of responses both within and between trials were examined in three experiments. The first experiment demonstrates that the sample information contained in first-choice errors is not sufficient to account for the observed pattern of second choices. This result implies that second-choices following first-choice errors are based on a second examination of the contents of working memory. Proactive interference was found in the second experiment in the form of a dependency, beyond that expected on the basis of trial independent response bias, of first-choices from one trial on the first-choice emitted on the previous trial. Samples from the previous trial were not found to exert a significant influence on later trials. The magnitude of the intertrial association (Experiment 3) did not depend on the duration of the intertrial interval. In contrast, longer intertrial intervals and longer sample durations did facilitate choice accuracy, by strengthening the association between current samples and choices. These results are incompatible with a trace-decay and competition model; they suggest strongly that multiple influences act simultaneously and independently to control delayed matching-to-sample responding. These multiple influences include memory for the choice occurring on the previous trial, memory for the sample, and general effects of trial spacing.

  1. The use of laser-induced fluorescence or ultraviolet detectors for sensitive and selective analysis of tobramycin or erythropoietin in complex samples

    Science.gov (United States)

    Ahmed, Hytham M.; Ebeid, Wael B.

    2015-05-01

    Complex samples analysis is a challenge in pharmaceutical and biopharmaceutical analysis. In this work, tobramycin (TOB) analysis in human urine samples and recombinant human erythropoietin (rhEPO) analysis in the presence of similar protein were selected as representative examples of such samples analysis. Assays of TOB in urine samples are difficult because of poor detectability. Therefore laser induced fluorescence detector (LIF) was combined with a separation technique, micellar electrokinetic chromatography (MEKC), to determine TOB through derivatization with fluorescein isothiocyanate (FITC). Borate was used as background electrolyte (BGE) with negative-charged mixed micelles as additive. The method was successively applied to urine samples. The LOD and LOQ for Tobramycin in urine were 90 and 200 ng/ml respectively and recovery was >98% (n = 5). All urine samples were analyzed by direct injection without sample pre-treatment. Another use of hyphenated analytical technique, capillary zone electrophoresis (CZE) connected to ultraviolet (UV) detector was also used for sensitive analysis of rhEPO at low levels (2000 IU) in the presence of large amount of human serum albumin (HSA). Analysis of rhEPO was achieved by the use of the electrokinetic injection (EI) with discontinuous buffers. Phosphate buffer was used as BGE with metal ions as additive. The proposed method can be used for the estimation of large number of quality control rhEPO samples in a short period.

  2. Effect of Build Angle on Surface Properties of Nickel Superalloys Processed by Selective Laser Melting

    Science.gov (United States)

    Covarrubias, Ernesto E.; Eshraghi, Mohsen

    2018-03-01

    Aerospace, automotive, and medical industries use selective laser melting (SLM) to produce complex parts through solidifying successive layers of powder. This additive manufacturing technique has many advantages, but one of the biggest challenges facing this process is the resulting surface quality of the as-built parts. The purpose of this research was to study the surface properties of Inconel 718 alloys fabricated by SLM. The effect of build angle on the surface properties of as-built parts was investigated. Two sets of sample geometries including cube and rectangular artifacts were considered in the study. It was found that, for angles between 15° and 75°, theoretical calculations based on the "stair-step" effect were consistent with the experimental results. Downskin surfaces showed higher average roughness values compared to the upskin surfaces. No significant difference was found between the average roughness values measured from cube and rectangular test artifacts.

  3. Interface Pattern Selection in Directional Solidification

    Science.gov (United States)

    Trivedi, Rohit; Tewari, Surendra N.

    2001-01-01

    The central focus of this research is to establish key scientific concepts that govern the selection of cellular and dendritic patterns during the directional solidification of alloys. Ground-based studies have established that the conditions under which cellular and dendritic microstructures form are precisely where convection effects are dominant in bulk samples. Thus, experimental data can not be obtained terrestrially under pure diffusive regime. Furthermore, reliable theoretical models are not yet possible which can quantitatively incorporate fluid flow in the pattern selection criterion. Consequently, microgravity experiments on cellular and dendritic growth are designed to obtain benchmark data under diffusive growth conditions that can be quantitatively analyzed and compared with the rigorous theoretical model to establish the fundamental principles that govern the selection of specific microstructure and its length scales. In the cellular structure, different cells in an array are strongly coupled so that the cellular pattern evolution is controlled by complex interactions between thermal diffusion, solute diffusion and interface effects. These interactions give infinity of solutions, and the system selects only a narrow band of solutions. The aim of this investigation is to obtain benchmark data and develop a rigorous theoretical model that will allow us to quantitatively establish the physics of this selection process.

  4. Evaluation of the effects of patient-selected music therapy on the sleep quality and pain intensity of burn patients

    Directory of Open Access Journals (Sweden)

    Fatemeh Muhaddith Ardabili

    2016-02-01

    Full Text Available Background: Sleep disturbances and pain are some of the most common problems among burn patients, which have adverse effects on recovery process and patient comfort. Given the use of music as a non-pharmacological approach to alleviate pain and provide comfort, this study aimed to evaluate the effect of patient-selected music on sleep quality and pain intensity in burn patients. Methods: This clinical trial was conducted on burn patients hospitalized in one of the hospitals of Tehran, Iran in 2015. In total, 50 patients were selected using randomized convenience sampling and divided into two intervention (n=25 and control (n=25 groups. Intervention was carried out for the intervention group through playing instrumental music, selected by the patients, in three consecutive 45-minute sessions before sleep. Severity of pain in the participants was evaluated for three nights (before and five minutes after the intervention using visual analog scale (VAS. In addition, sleep quality of the samples was assessed three days before the intervention using Pittsburgh sleep quality index (PSQI and during the post-intervention days through interviews. The mentioned scales were applied for the control group as well. Data analysis was performed in SPSS version 18 using Chi-square, as well as paired and independent t-tests. Results: In this study, a significant improvement was observed in sleep quality (P<0.001 and pain intensity (P=0.012 in the participants of intervention group after listening to music. Moreover, a significant difference was observed between the study groups after the intervention in terms of mean sleep quality score (P<0.001 and pain intensity (P=0.046. Conclusion: According to the results of this study, application of patient-selected music therapy could be associated with a significant improve in sleep quality and decrease in pain intensity in burn patients. Therefore, it is recommended that this intervention approach be applied by

  5. Volume 9 No. 3 2009 May 2009 830 EFFECT OF SELECTED ...

    African Journals Online (AJOL)

    EFFECT OF SELECTED WASHING TREATMENTS AND DRYING ... chlorinated solutions (100ppm) and potable tap water (control). Results indicated that ... The constraints to effective and hygienic production of sun-dried dagaa indicate need.

  6. [Application of wavelength selection algorithm to measure the effective component of Chinese medicine based on near-infrared spectroscopy].

    Science.gov (United States)

    Gu, Xiao-Yu; Xu, Ke-Xin; Wang, Yan

    2006-09-01

    Near infrared (NIR) spectroscopy has raised a lot of interest in the pharmaceutical industry because it is a rapid and cost-effective analytical type of spectroscopy with no need for extensive sample preparation, and with the easy-realizable ability of on-line application. The NIR technology can increase the quality control standard of the Chinese medicine and accelerate the entry into the international market. In the present paper, two methods for wavelength selection are applied to the measurement of borneol, one of which is the multiple-chain stepwise, which tends to select many variables in the same area containing valuable information, and the other is the mixture genetic algorithm, which incorporates simulated annealing so as to improve the local searching ability while maintaining the global searching ability. The results present that the number of wavelength is reduced to 16% compared with the original number of wavelength, and the prediction accuracy has increased 47.6%. Therefore, the method of wavelength selection is a good way to enhance the prediction accuracy and simplify the model in NIR region.

  7. Heterozygote advantage: the effect of artificial selection in livestock and pets.

    Science.gov (United States)

    Hedrick, Philip W

    2015-01-01

    There are a number of mutants in livestock and pets that have a heterozygote advantage because of artificial selection for these mutants in heterozygotes and strong detrimental effects from natural selection in homozygotes. In livestock, these mutants include ones that influence milk yield in dairy cattle, fecundity in sheep, litter size in pigs, muscling in beef cattle, color in horses, lean meat content in pigs, and comb morphology in chickens. In pets, these mutants include ones that influence tail length in cats and hairlessness, muscling, color, or ridgeback hair in dogs. A large variety of mutants are responsible, including small or large deletions or insertions and single base-pair nonsynonymous changes. Many of the mutants cause loss of function for the genes involved, a change that results in the pleiotropic effects of a desired phenotype in heterozygotes and low fitness or an undesirable phenotype in mutant homozygotes. I examine how selection changes the frequency of these mutants and provide an approach to estimate the amount of artificial selection that is necessary to maintain these mutants at the high frequencies often observed. The amount of artificial selection ranges from low selection favoring heterozygotes for double muscling in whippet dogs to very strong selection favoring the "flash" (part white, part solid) heterozygote in boxer dogs and the rose comb in chickens. In several examples (rose comb in Wyandotte chickens and the hair ridge in Rhodesian ridgeback dogs), there is actually stronger selection for the mutant than against it, making the frequency of the mutant greater than 50%. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Methodology Series Module 5: Sampling Strategies

    Science.gov (United States)

    Setia, Maninder Singh

    2016-01-01

    Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ‘ Sampling Method’. There are essentially two types of sampling methods: 1) probability sampling – based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling – based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample) is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term ‘ random sample’ when the researcher has used convenience sample). The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the ‘ generalizability’ of these results. In such a scenario, the researcher may want to use ‘ purposive sampling’ for the study. PMID:27688438

  9. Using lot quality-assurance sampling and area sampling to identify priority areas for trachoma control: Viet Nam.

    Science.gov (United States)

    Myatt, Mark; Mai, Nguyen Phuong; Quynh, Nguyen Quang; Nga, Nguyen Huy; Tai, Ha Huy; Long, Nguyen Hung; Minh, Tran Hung; Limburg, Hans

    2005-10-01

    To report on the use of lot quality-assurance sampling (LQAS) surveys undertaken within an area-sampling framework to identify priority areas for intervention with trachoma control activities in Viet Nam. The LQAS survey method for the rapid assessment of the prevalence of active trachoma was adapted for use in Viet Nam with the aim of classifying individual communes by the prevalence of active trachoma among children in primary school. School-based sampling was used; school sites to be sampled were selected using an area-sampling approach. A total of 719 communes in 41 districts in 18 provinces were surveyed. Survey staff found the LQAS survey method both simple and rapid to use after initial problems with area-sampling methods were identified and remedied. The method yielded a finer spatial resolution of prevalence than had been previously achieved in Viet Nam using semiquantitative rapid assessment surveys and multistage cluster-sampled surveys. When used with area-sampling techniques, the LQAS survey method has the potential to form the basis of survey instruments that can be used to efficiently target resources for interventions against active trachoma. With additional work, such methods could provide a generally applicable tool for effective programme planning and for the certification of the elimination of trachoma as a blinding disease.

  10. [Effects of sampling plot number on tree species distribution prediction under climate change].

    Science.gov (United States)

    Liang, Yu; He, Hong-Shi; Wu, Zhi-Wei; Li, Xiao-Na; Luo, Xu

    2013-05-01

    Based on the neutral landscapes under different degrees of landscape fragmentation, this paper studied the effects of sampling plot number on the prediction of tree species distribution at landscape scale under climate change. The tree species distribution was predicted by the coupled modeling approach which linked an ecosystem process model with a forest landscape model, and three contingent scenarios and one reference scenario of sampling plot numbers were assumed. The differences between the three scenarios and the reference scenario under different degrees of landscape fragmentation were tested. The results indicated that the effects of sampling plot number on the prediction of tree species distribution depended on the tree species life history attributes. For the generalist species, the prediction of their distribution at landscape scale needed more plots. Except for the extreme specialist, landscape fragmentation degree also affected the effects of sampling plot number on the prediction. With the increase of simulation period, the effects of sampling plot number on the prediction of tree species distribution at landscape scale could be changed. For generalist species, more plots are needed for the long-term simulation.

  11. Groundwater sampling in uranium reconnaissance

    International Nuclear Information System (INIS)

    Butz, T.R.

    1977-03-01

    The groundwater sampling program is based on the premise that ground water geochemistry reflects the chemical composition of, and geochemical processes active in the strata from which the sample is obtained. Pilot surveys have shown that wells are the best source of groundwater, although springs are sampled on occasion. The procedures followed in selecting a sampling site, the sampling itself, and the field measurements, as well as the site records made, are described

  12. Greenhouse Effect Detection Experiment (GEDEX). Selected data sets

    Science.gov (United States)

    Olsen, Lola M.; Warnock, Archibald, III

    1992-01-01

    This CD-ROM contains selected data sets compiled by the participants of the Greenhouse Effect Detection Experiment (GEDEX) workshop on atmospheric temperature. The data sets include surface, upper air, and/or satellite-derived measurements of temperature, solar irradiance, clouds, greenhouse gases, fluxes, albedo, aerosols, ozone, and water vapor, along with Southern Oscillation Indices and Quasi-Biennial Oscillation statistics.

  13. Internal calibration on adjacent samples (InCAS) with Fourier transform mass spectrometry.

    Science.gov (United States)

    O'Connor, P B; Costello, C E

    2000-12-15

    Using matrix-assisted laser desorption/ionization (MAL DI) on a trapped ion mass spectrometer such as a Fourier transform mass spectrometer (FTMS) allows accumulation of ions in the cell from multiple laser shots prior to detection. If ions from separate MALDI samples are accumulated simultaneously in the cell, ions from one sample can be used to calibrate ions from the other sample. Since the ions are detected simultaneously in the cell, this is, in effect, internal calibration, but there are no selective desorption effects in the MALDI source. This method of internal calibration with adjacent samples is demonstrated here on cesium iodide clusters, peptides, oligosaccharides, poly(propylene glycol), and fullerenes and provides typical FTMS internal calibration mass accuracy of < 1 ppm.

  14. Effect of inter-species selective interactions on the thermodynamics and nucleation free-energy barriers of a tessellating polyhedral compound

    International Nuclear Information System (INIS)

    Escobedo, Fernando A.

    2016-01-01

    The phase behavior and the homogeneous nucleation of an equimolar mixture of octahedra and cuboctahedra are studied using thermodynamic integration, Gibbs-Duhem integration, and umbrella sampling simulations. The components of this mixture are modeled as polybead objects of equal edge lengths so that they can assemble into a space-filling compound with the CsCl crystal structure. Taking as reference the hard-core system where the compound crystal does not spontaneously nucleate, we quantified the effect of inter-species selective interactions on facilitating the disorder-to-order transition. Facet selective and facet non-selective inter-species attractions were considered, and while the former was expectedly more favorable toward the target tessellating structure, the latter was found to be similarly effective in nucleating the crystal compound. Ranges for the strength of attractions and degree of supersaturation were identified where the nucleation free-energy barrier was small enough to foretell a fast process but large enough to prevent spinodal fluctuations that can trap the system in dense metastable states lacking long-range order. At those favorable conditions, the tendency toward the local orientational order favored by packing entropy is amplified and found to play a key role seeding nuclei with the CsCl structure.

  15. EFFECT OF CORE TRAINING ON SELECTED HEMATOLOGICAL VARIABLES AMONG BASKETBALL PLAYERS

    OpenAIRE

    K. Rejinadevi; Dr. C. Ramesh

    2017-01-01

    The purpose of the study was to find out the effect of core training on selected haematological variables among basketball players. For the purpose of the study forty men basketball players were selected as subjects from S.V.N College and Arul Anandar College, Madurai, Tamilnadu at random and their age ranged from 18 to 25 years. The selected subjects are divided in to two groups of twenty subjects each. Group I acted as core training group and Group II acted as control group. The experimenta...

  16. Water pollution screening by large-volume injection of aqueous samples and application to GC/MS analysis of a river Elbe sample

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S.; Efer, J.; Engewald, W. [Leipzig Univ. (Germany). Inst. fuer Analytische Chemie

    1997-03-01

    The large-volume sampling of aqueous samples in a programmed temperature vaporizer (PTV) injector was used successfully for the target and non-target analysis of real samples. In this still rarely applied method, e.g., 1 mL of the water sample to be analyzed is slowly injected direct into the PTV. The vaporized water is eliminated through the split vent. The analytes are concentrated onto an adsorbent inside the insert and subsequently thermally desorbed. The capability of the method is demonstrated using a sample from the river Elbe. By means of coupling this method with a mass selective detector in SIM mode (target analysis) the method allows the determination of pollutants in the concentration range up to 0.01 {mu}g/L. Furthermore, PTV enrichment is an effective and time-saving method for non-target analysis in SCAN mode. In a sample from the river Elbe over 20 compounds were identified. (orig.) With 3 figs., 2 tabs.

  17. Temperature effects on the electrohydrodynamic and electrokinetic behaviour of ion-selective nanochannels

    International Nuclear Information System (INIS)

    Wood, Jeffery A; Benneker, Anne M; Lammertink, Rob G H

    2016-01-01

    A non-isothermal formulation of the Poisson–Nernst–Planck with Navier–Stokes equations is used to study the influence of heating effects in the form of Joule heating and viscous dissipation and imposed temperature gradients on a microchannel/nanochannel system. The system is solved numerically under various cases in order to determine the influence of temperature-related effects on ion-selectivity, flux and fluid flow profiles, as well as coupling between these phenomena. It is demonstrated that for a larger reservoir system, the effects of Joule heating and viscous dissipation only become relevant for higher salt concentrations and electric field strengths than are compatible with ion-selectivity due to Debye layer overlap. More interestingly, it is shown that using different temperature reservoirs can have a strong influence on ion-selectivity, as well as the induced electrohydrodynamic flows. (paper)

  18. SPME GC/MS determination of organochlorine pesticides in water samples

    Directory of Open Access Journals (Sweden)

    Yerbolat Sailaukhanuly

    2013-05-01

    Full Text Available Headspace solid phase microextraction (HS-SPME in combination with gas chromatography and mass-spectrometry (GC/MS was studied for analysis of water samples. The organochlorine pesticides (OCPs, p,p'-DDT, p,p'-DDD, and p,p'-DDE were collected and analyzed by GC/MS. To select of effective fiber coatings four types of SPME fibers were examined and compared. The parameters effecting the efficiency of HS-SPME such as extraction and pre-incubation time and extraction temperature, effect of solvent nature, ionic strength were studied to obtain optimal parameters. The method was developed using spiked water samples in a concentration range  10 - 500 ng/L. The calibration curve was linear over the studied concentration range with r≥0.9925. The detection limits varied from 1.57 to 2.08 ng/L. An authentic water samples from contaminated lake with OCPs were analyzed by developed method.

  19. Effect of cooking methods on the micronutrient profile of selected ...

    African Journals Online (AJOL)

    Effect of cooking methods on the micronutrient profile of selected vegetables: okra fruit ( Abelmoshcus esculentus ), fluted pumpkin ( Telfairia occidentalis ), African spinach ( Amarantus viridis ), and scent leaf ( Ocumum gratissimum.

  20. Reducing the sampling frequency of groundwater monitoring wells

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, V.M.; Ridley, M.N. [Lawrence Livermore National Lab., CA (United States); Tuckfield, R.C.; Anderson, R.A. [Westinghouse, Savannah River Co., Aiken, SC (United States)

    1996-01-01

    As part of a joint LLNL/SRTC project, a methodology for selecting sampling frequencies is evolving that introduces statistical thinking and cost effectiveness into the sampling schedule selection practices now commonly employed on environmental projects. Our current emphasis is on descriptive rather than inferential statistics. Environmental monitoring data are inherently messy, being plagued by such problems as extremely high variability and left-censoring. As a result, real data often fail to meet the assumptions required for the appropriate application of many statistical methods. Rather than abandon the quantitative approach in these cases, however, the methodology employs simple statistical techniques to bring a measure of objectivity and reproducibility to the process. The techniques are applied within the framework of decision logic, which inrerprets the numerical results from the standpoint of chemistry-related professional judgment and the regulatory context. This paper presents the methodology`s basic concepts together with early implementation results, showing the estimated cost savings. 6 refs., 3 figs.