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Hopper, R. J. "The effects and implications of sampling clay soils." Thesis, University of Surrey, 1992. http://epubs.surrey.ac.uk/804887/.
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Hicks, William T. "Analysis of the Effects of Sampling Sampled Data." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611440.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe traditional use of active RC-type filters as anti-aliasing filters in Pulse Code Modulation (PCM) systems is being replaced by the use of Digital Signal Processing (DSP) filters, especially when performance requirements are tight and when operation over a wide environmental temperature range is required. In order to keep systems more flexible, it is often desired to let the DSP filters run asynchronous to the PCM sample clock. This results in the PCM output signal being a sampling of the output of the DSP, which is itself a sampling of the input signal. In the analysis of the PCM data, the signal will have a periodic repeat of a previous sample, or a missing sample, depending on the relative sampling rates of the DSP and the PCM. This paper analyzes what effects can be expected in the analysis of the PCM data when these anomalies are present. Results are presented which allow the telemetry engineer to make an effective value judgment based on the type of filtering technology to be employed and on the desired system performance.
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Tse, Kwok Ho. "Sample size calculation : influence of confounding and interaction effects /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?MATH%202006%20TSE.
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Smith, Corey B. "The effects of chorionic villus sampling upon marital adjustment." Theological Research Exchange Network (TREN), 1994. http://www.tren.com.
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Prevost, Andrew Toby. "Multilevel modelling of child mortality : Gibbs sampling versus other approaches." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242478.
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Chen, Liang. "Small population bias and sampling effects in stochastic mortality modelling." Thesis, Heriot-Watt University, 2017. http://hdl.handle.net/10399/3372.
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Pension schemes are facing more difficulties on matching their underlying liabilities with assets, mainly due to faster mortality improvements for their underlying populations, better environments and medical treatments and historically low interest rates. Given most of the pension schemes are relatively much smaller than the national population, modelling and forecasting the small populations' longevity risk become urgent tasks for both the industrial practitioners and academic researchers. This thesis starts with a systematic analysis on the influence of population size on the uncertainties of mortality estimates and forecasts with a stochastic mortality model, based on a parametric bootstrap methodology with England and Wales males as our benchmark population. The population size has significant effect on the uncertainty of mortality estimates and forecasts. The volatilities of small populations are over-estimated by the maximum likelihood estimators. A Bayesian model is developed to improve the estimation of the volatilities and the predictions of mortality rates for the small populations by employing the information of larger population with informative prior distributions. The new model is validated with the simulated small death scenarios. The Bayesian methodologies generate smoothed estimations for the mortality rates. Moreover, a methodology is introduced to use the information of large population for obtaining unbiased volatilities estimations given the underlying prior settings. At last, an empirical study is carried out based on the Scotland mortality dataset.
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Smith, Christina D. "Estimation of treatment effects under combined sampling and experimental designs." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/282.
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Jia, Yue. "Using sampling weights in the estimation of random effects model." Ann Arbor, Mich. : ProQuest, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3258527.
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Thesis (Ph.D. in Statistical Science)--S.M.U., 2007.Title from PDF title page (viewed Mar. 18, 2008). Source: Dissertation Abstracts International, Volume: 68-04, Section: B, page: 2431. Adviser: Lynne Stokes. Includes bibliographical references.
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Tansey, Joshua. "The effects of clumped log distribution on line intersect sampling." Thesis, University of Canterbury. School of Forestry, 2014. http://hdl.handle.net/10092/10463.
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Line intersect sampling (LIS) is a method used for quantifying post-harvest waste. It is often used by forest managers to quantify merchantable volume remaining on the cutover so that compensation may be exacted under stumpage contracts.
The theory has been extensively studied and will produce an accurate measure of harvest waste given the basic theoretical assumptions that: all logs are cylindrical, occur horizontally, are randomly orientated and randomly distributed. When these assumptions are violated, the method is not biased, although precision decreases substantially.
A computer simulation was completed to determine whether or not the LIS method is appropriate, given a clumped distribution of logs produced by processing at central sites in cutover before using a forwarder to extract to the landing. The software ArcGIS with the application ModelBuilder was used to produce the LIS Model for running LIS assessments.
It was determined through simulation that the conventional LIS method is not appropriate given these harvesting methods, as a level of bias was found in sampling determining that the LIS method underestimated true volume. T-tests confirmed the significance of this bias.
LIS volume estimates were not precise, with the range of estimates ranging from 0 m3/ha to double the true volume. An increase in sampling length by a third was found to increase precision by only a small amount. Therefore, it was determine that increased sampling is not worthwhile as the costs associated with it do not justify the small increase in precision.
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Miracle, Sarah. "The effects of bias on sampling algorithms and combinatorial objects." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53526.
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Markov chains are algorithms that can provide critical information from exponentially large sets efficiently through random sampling. These algorithms are ubiquitous across numerous scientific and engineering disciplines, including statistical physics, biology and operations research. In this thesis we solve sampling problems at the interface of theoretical computer science with applied computer science, discrete mathematics, statistical physics, chemistry and economics. A common theme throughout each of these problems is the use of bias.
The first problem we study is biased permutations which arise in the context of self-organizing lists. Here we are interested in the mixing time of a Markov chain that performs nearest neighbor transpositions in the non-uniform setting. We are given "positively biased'' probabilities $\{p_{i,j} \geq 1/2 \}$ for all $i < j$ and let $p_{j,i} = 1-p_{i,j}$. In each step, the chain chooses two adjacent elements~$k,$ and~$\ell$ and exchanges their positions with probability $p_{ \ell, k}$. We define two general classes of bias and give the first proofs that the chain is rapidly mixing for both. We also demonstrate that the chain is not always rapidly mixing by constructing an example requiring exponential time to converge to equilibrium.
Next we study rectangular dissections of an $n \times n$ lattice region into rectangles of area $n$, where $n=2^k$ for an even integer $k.$ We consider a weighted version of a natural edge flipping Markov chain where, given a parameter $\lambda > 0,$ we would like to generate each rectangular dissection (or dyadic tiling)~$\sigma$ with probability proportional to $\lambda^{|\sigma|},$ where $|\sigma|$ is the total edge length.
First we look at the restricted case of dyadic tilings, where each rectangle is required to have the form $R = [s2^{u},(s+1)2^{u}]\times [t2^{v},(t+1)2^{v}],$ where $s, t, u$ and~$v$ are nonnegative integers. Here we show there is a phase transition: when $\lambda < 1,$ the edge-flipping chain mixes in time $O(n^2 \log n)$, and when $\lambda > 1,$ the mixing time is $\exp(\Omega({n^2}))$. The behavior for general rectangular dissections is more subtle, and we show the chain requires exponential time when $\lambda >1$ and when $\lambda <1.$
The last two problems we study arise directly from applications in chemistry and economics. Colloids are binary mixtures of molecules with one type of molecule suspended in another. It is believed that at low density typical configurations will be well-mixed throughout, while at high density they will separate into clusters. We characterize the high and low density phases for a general family of discrete interfering colloid models by showing that they exhibit a "clustering property" at high density and not at low density. The clustering property states that there will be a region that has very high area to perimeter ratio and very high density of one type of molecule. A special case is mixtures of squares and diamonds on $\Z^2$ which correspond to the Ising model at fixed magnetization.
Subsequently, we expanded techniques developed in the context of colloids to give a new rigorous underpinning to the Schelling model, which was proposed in 1971 by economist Thomas Schelling to understand the causes of racial segregation. Schelling considered residents of two types, where everyone prefers that the majority of his or her neighbors are of the same type. He showed through simulations that even mild preferences of this type can lead to segregation if residents move whenever they are not happy with their local environments. We generalize the Schelling model to include a broad class of bias functions determining individuals happiness or desire to move. We show that for any influence function in this class, the dynamics will be rapidly mixing and cities will be integrated if the racial bias is sufficiently low. However when the bias is sufficiently high, we show the dynamics take exponential time to mix and a large cluster of one type will form.
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Sherratt, Susan Mary. "Oral discourse : right brain damage, demographic variables and sampling effects." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271163.
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Lau, Cheung-na. "Interviewer effects in sample surveys." [Hong Kong] : University of Hong Kong, 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13064794.
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Tüchler, Regina. "Bayesian Variable Selection for Logistic Models Using Auxiliary Mixture Sampling." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2006. http://epub.wu.ac.at/984/1/document.pdf.
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The paper presents an Markov Chain Monte Carlo algorithm for both variable and covariance selection in the context of logistic mixed effects models. This algorithm allows us to sample solely from standard densities, with no additional tuning being needed. We apply a stochastic search variable approach to select explanatory variables as well as to determine the structure of the random effects covariance matrix. For logistic mixed effects models prior determination of explanatory variables and random effects is no longer prerequisite since the definite structure is chosen in a data-driven manner in the course of the modeling procedure. As an illustration two real-data examples from finance and tourism studies are given. (author's abstract)Series: Research Report Series / Department of Statistics and Mathematics
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Turner, Barry John. "Spatial sampling and vertical variability effects on microwave radiometer rainfall estimates." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59910.
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Three-dimensional radar data for three Florida storms are used with a radiative transfer model to simulate observations at 19 GHz by a nadir pointing, satellite bourne microwave radiometer. Estimates were made of spatial sampling errors due to both horizontal and vertical variability of the precipitation. Calibrated radar data were taken as realistic representations of rainfall fields.The optimal conversion between microwave brightness temperature and rainfall rate was highly sensitive to the spatial resolution of observations. Retrievals were made from the simulated microwave measurements using rainfall retrieval functions optimized for each resolution and for each storm case.
There is potential for microwave radiometer measurements from the planned TRMM satellite to provide better 'snapshot' estimates than area-threshold VIS/IR methods. Variability of the vertical profile of precipitation did not seriously reduce accuracy. However, it is crucial that calibration of retrieval methods be done with ground truth of the same spatial resolution.
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Wan, Hongbin. "Efficient sampling of protein conformational dynamics and prediction of mutation effects." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/575951.
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ChemistryPh.D.
Molecular dynamics (MD) simulation is a powerful tool enabling researchers to gain insight into biological processes at the atomic level. There have been many advancements in both hardware and software in the last decade to both accelerate MD simulations and increase their predictive accuracy; however, MD simulations are typically limited to the microsecond timescale, whereas biological motions can take seconds or longer. Because of this, it remains extremely challenging to restrain simulations using ensemble-averaged experimental observables. Among various approaches to elucidate the kinetics of molecular simulations, Markov State Models (MSMs) have proven their ability to extract both kinetic and thermodynamic properties of long-timescale motions using ensembles of shorter MD simulation trajectories. In this dissertation, we have implemented an MSM path-entropy method, based on the idea of maximum-caliber, to efficiently predict the changes in protein folding behavior upon mutation. Next, we explore the accuracy of different MSM estimators applied to trajectory data obtained by adaptive seeding, in which new rounds of short MD simulations are collected from states of interest, and propose a simple method to build accurate models by population re-weighting of the transition count matrix. Finally, we explore ways to reconcile simulated ensembles with Hydrogen/Deuterium exchange (HDX) protection measurements, by constructing multi-ensemble Markov State Models (MEMMs) from biased MD simulations, and reconciling these predictions against the experimental data using the BICePs (Bayesian Inference of Conformational Populations) algorithm. We apply this approach to model the native-state conformational ensemble of apomyoglobin at neutral pH.
Temple University--Theses
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Smolensky, Nicole Limunga. "Population enumeration and the effects of oil and gas development on dune-dwelling lizards." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2848.
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Neal, Emily R. "ESCHERICHIA COLI STRAIN DIVERSITY IN HUMANS: EFFECTS OF SAMPLING EFFORT AND METHODOLOGY." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/984.
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Studies investigating Escherichia coli strain diversity and demographics in human hosts are frequently inconsistent regarding sampling effort and methodology while current strain typing methods are often expensive or laborious. To rectify these inconsistencies, sampling effort was investigated by comparing the diversity of 15-isolate collections to 100-isolate collections from 3 human subjects. Temporal variation in E. coli strain diversity was also studied by collecting 15 isolates once every 6 months. Additionally, strain identification and diversity collected by different sampling methods (fecal swabs vs. anal swabs collected at different times around defecation) were compared to identify any inherent biases in sampling method. This study employed pyroprinting, a new inexpensive and simple strain typing method using pyrosequencing, to generate DNA fingerprints (or pyroprints) based on the Intergenic Transcribed Spacer sequences in the ribosomal RNA operon to differentiate E. coli strains. Differences in strain diversity were apparent when comparing sampling efforts. The sampling effort investigation suggested that certain subjects hosted very large and highly diverse E. coli strain populations such that even 100 isolates may not fully represent E. coli strain populations in human hosts. Instead, the sampling effort required to accurately represent strain demographics may depend on strain richness and evenness within each host. The temporal investigation yielded similar or greater strain abundance and diversity compared to other typing methods in the literature suggesting pyroprinting is a similarly discriminating tool. When agglomerated over time or by subject, no significant differences in diversity were observed between subjects or between sampling methods despite visible differences in strain richness and evenness.
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Sihabut, Tanasri McDow Stephen R. "Sampling artifacts of particulate organic species and their effects on receptor modeling results /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/512.
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Sealey, Linda Rae. "Effects of language sampling task on language production in children with typical development." Oklahoma City : [s.n.], 2008.
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Mullett, Timothy L. "Decision by sampling and rank order effects in value judgement and decision making." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14293/.
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This thesis uses the Decision by Sampling model as a basis for examining effects of rank order encoding in value judgement and preferential choice. A range of experiments are reported, and these employ a variety of methodologies including behavioural paradigms, eye tracking and functional MRI. The results show that when there are a relatively small number of values used during an experiment, participants encode utility based upon the rank order of a potential outcome within these values. By introducing different decision contexts where the experienced values have a positive or negative skew, an individual’s utility curve can be made concave and risk averse or convex and risk seeking. These different utility curves can be produced within the same individual and same task simply by providing a contextual cue for each trial. Two fMRI experiments demonstrate the neural systems underlying this phenomenon. The results show that all regions of the reward network encode reward as a function of the reward’s rank order within the current context. No region of the brain was found to encode a reward’s absolute financial value. Other experiments investigated choice and valuation in more complex decision environments. It was found that when the number of experienced values is significantly larger than working memory capacity DbS is a relatively poor predictor of behaviour. The Weighted ADDitive rule proved to be more accurate throughout. However, in multi-attribute choice experiments where one attribute had a manipulated distribution, individuals use and weighting of the attribute value was determined by rank order rather than its numerical value. The specific characteristics of this were found to be incompatible with an exemplar based model of recall and binary comparison to specific items. It was instead found to be compatible with non-exemplar, fuzzy trace theories of decision making which are based upon estimates of the distribution. Eye tracking during multi-attribute choice additionally shows that participants begin to attend more to their preferred choice as they near the point at which they respond. However, they do not attend more to the attributes which they weight more highly in their choices, questioning the validity of previous eye-tracking findings.
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Cole, James Jacob. "Assessing Nonlinear Relationships through Rich Stimulus Sampling in Repeated-Measures Designs." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/dissertations/1587.
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Explaining a phenomenon often requires identification of an underlying relationship between two variables. However, it is common practice in psychological research to sample only a few values of an independent variable. Young, Cole, and Sutherland (2012) showed that this practice can impair model selection in between-subject designs. The current study expands that line of research to within-subjects designs. In two Monte Carlo simulations, model discrimination under systematic sampling of 2, 3, or 4 levels of the IV was compared with that under random uniform sampling and sampling from a Halton sequence. The number of subjects, number of observations per subject, effect size, and between-subject parameter variance in the simulated experiments were also manipulated. Random sampling out-performed the other methods in model discrimination with only small, function-specific costs to parameter estimation. Halton sampling also produced good results but was less consistent. The systematic sampling methods were generally rank-ordered by the number of levels they sampled.
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HUANG, YAO-CHIN. "EFFECTS OF ROBOTIC PRESCRIPTION DISPENSING SYSTEM ON OUTPATIENT PHARMACY OPERATIONS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022594955.
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Provost, Paul Graham. "The persistence and effects of antibacterial agents in marine fish farm sediments." Thesis, Edinburgh Napier University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369173.
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Nagel, Cody J. "Effects of spatial and temporal variation on sampling strategies targeting a community of fishes." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1391678.
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Yellow perch, alewife, spottail shiner and round goby trawl catch per unit effort (CPUE) was evaluated in the Indiana waters of Lake Michigan from 1984-2006 to determine whether spatial or temporal variation in CPUE for these species occurred. Differences in CPUE among sites or periods were not clearly distinguished within a single sampling year. However, when compared over a 23 year time frame, spatial and temporal differences became evident. To determine the minimum number of samples needed to detect differences among sites and periods, we ran a Monte Carlo simulation using 23 years of empirical data. This compared favorably to results obtained from a power analysis that identified the minimum number of samples required to identify statistical differences. Sampling effort needed to distinguish differences in CPUE varied both spatially and temporally among the four species. Differences in sampling only became evident when multi-year efforts were employed. In addition, spatial and temporal differences in male and female (mature and immature) yellow perch proportions was also evaluated among our sample sites and periods from 1993-2006.Department of Biology
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Hajj, Ahmed Ramez. "The simulation of sampling disturbance and its effects on the deformation behaviour of clays." Thesis, University of Sheffield, 1991. http://etheses.whiterose.ac.uk/14450/.
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The importance of studying the behaviour of soil at small strain levels (« 0.1 %) has been increasingly recognised in recent years. In the laboratory, tests are usually conducted on tube samples retrieved from the ground, which inevitably suffer from disturbance. This thesis describes an investigation of the effects of sampling disturbance on the small strain behaviour of one-dimensionally consolidated kaolin. Following the suggestion of Baligh (1985), tube sampling disturbance was simulated by applying a strain cycle in the triaxial cell. Comparative tests on 'disturbed' and 'undisturbed' specimens were conducted in a specially designed 100 mm hydraulic triaxial apparatus. Tests were also carried out in a 38 mm triaxial cell to study the effects of loading rate and overconsolidation ratio on the small strain deformation behaviour of isotropically consolidated kaolin. In the 100 mm cell the local axial and radial strains were measured using proximity transducers mounted on adjustable fittings, enabling small strains to be measured accurately at any stage of a test. The axial strain was also measured between the end caps and externally. Comparisons of these three axial strain measurements showed that, under favourable conditions when bedding errors arc negligible, end cap or external strains may be considered satisfactory. Bedding errors are reduced by consolidating the specimen to a high stress level and providing a rigid connection to the top cap. External strains must be corrected for equipment compliance. Tests for the effects of sampling disturbance indicated that reconsolidating disturbed specimens to their initial stress conditions results in an adequate recovery of the small strain stiffness, but yields a higher stiffness at larger strains. The recovery of the small strain stiffness was better in compression tests than in extension tests and further work is required to understand this finding. Specimens were observed to approach failure during the simulation of sampling disturbance. For isotropically consolidated specimens, the relationships between normalised small strain stiffness at a given strain level and both overconsolidation ratio and rate of shearing were linear on a semi-logarithmic scale. This is in agreement with expectation on the basis of most previous research, but the effect of over consolidation ratio requires further study using one-dimensionally consolidated specimens. The experimental results were compared with the predictions from theoretical models based on critical state soil mechanics. These comparisons showed that the behaviour of kaolin under monotonic loading can be adequately predicted, even at small strains. Encouraging predictions were also made for behaviour during the loading cycle, as sampling disturbance was simulated. However, further theoretical developments are needed to take into account the rate of shearing. The critical state parameters derived from the present tests and used in the model predictions showed close agreement with those obtained by other researchers.
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劉長拿 and Cheung-na Lau. "Interviewer effects in sample surveys." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31976566.
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Nattino, Giovanni. "Causal Inference in Observational Studies with Complex Design: Multiple Arms, Complex Sampling and Intervention Effects." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1562582646286934.
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Rosdahl, Hans. "Microdialysis sampling from skeletal muscle and adipose tissue with special reference to the effects of insulin on tissue blood flow and glucose metabolism /." Stockholm, 1998. http://diss.kib.ki.se/1998/91-628-3050-3.
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Knapp, Shannon Michele. "Effects of Timber Harvesting on Terrestrial Salamander Abundance and Behavior." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/33408.
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We examined the short-term (1 - 4 years postharvest) effects of 7 silvicultural treatments on terrestrial salamander populations at 4 sites in southwest Virginia and West Virginia. The 3 silvicultural treatments with the most canopy removal (4-7 m2 basal area Shelterwood, Leavetree, Clearcut) had significantly fewer salamanders than the control (p < 0.10) postharvest. No differences were found among treatments in age class distribution, the percent of females that were gravid, or average clutch size.
We tested the nighttime, surface-count census method for visibility and behavior-induced bias among silviculture treatments and estimated the proportion of a salamander population that is active on the surface in harvested and control habitats. Instantaneous rates of salamander activity ranged from 1.3 to 11.7% of the population for redback (Plethodon cinereus) and slimy salamanders (P. glutinosus). Timber harvest caused up to a 2-fold increase or decrease in activity rates. There was evidence for bias in the night census method, but differences were not consistent enough to suggest general bias corrections.
We also tested whether poorly fed salamanders exhibited risk-sensitive foraging in a dry environment in a laboratory experiment. Poorly fed salamanders were observed out of their simulated burrows less than well fed salamanders suggesting salamanders, particularly females and small adults, are risk-averse.Master of Science
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Gill, Andrew Brian. "The analysis of dynamic contrast-enhanced magnetic resonance imaging data : treatment effects, sampling rates and repeatability." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648826.
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Silvia, E. Suyapa M. "Effects of sampling error and model misspecification on goodness of fit indices for structural equation models /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487597424138163.
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Shaughnessy, Mary Katherine. "THE EFFECTS OF VIDEO MODELING ON INSTRUCTIONAL AIDE STAFF BEHAVIOR IN A SELF-CONTAINED HIGH SCHOOL CLASSROOM." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2263.
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One way for students with disabilities to receive instructional support from someone other than the lead classroom teacher is through paraprofessionals. Paraprofessionals who are not trained properly, however, can negatively impact student success rates. One intervention that has been explored has been the use of video modeling to train staff on various instructional and behavior management strategies. The purpose of this study was to evaluate the effectiveness of using video training to teach paraprofessionals how to implement errorless learning strategies with students. The participants within this study were three female paraprofessionals that were of Caucasian, Latino, and Ukranian descent and had worked in a classroom for at least one year. The dependent variables within this study were evaluated by use of a single subject, multiple baseline design across participants. Results of this study revealed that video training with a focus on errorless learning was effective in increasing paraprofessional percent correct implementation of the strategy, as indicated by an increase in exhibition of the strategy throughout observation and generalization sessions. Paraprofessional implementation of errorless learning procedures increased from a mean of 12.5% accuracy during baseline to 84% accuracy during intervention sessions. Generalization probes maintained high accuracy rates as well, with a mean of 88% accuracy across all three participants. The social validity results provided to the participants at the end of the study indicated that all participants prefer video training over in person training.
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Slama, Nader. "Inclusion of dissipative effects in quantum time-dependent mean-field theories." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30063.
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Les théories de champ moyen quantique représentent une base robuste pour la description de la dynamique de nombreux systèmes physiques, des noyaux aux systèmes moléculaires et aux agrégats. Cependant, le traitement incomplet des corrélations électroniques au niveau du champ moyen empêche de donner une description propre de la dynamique, en particulier la dynamique dans les régimes dissipatifs. La dissipation est intrinsèquement liée à la thermalisation qui représente le phénomène cible à d'écrire dans ce travail. Nous avons exploré un schéma purement quantique en terme des matrices densités et qui consiste en l'inclusion des corrélations de type collisions, responsables de la thermalisation dans les systèmes quantiques finis. Ceci est fait en traitant les corrélations entre deux particules avec la théorie des perturbations dépendantes du temps tout au long d'un intervalle de temps. Ceci permet de créer un ensemble d'états de type champ moyen pur pour les différentes configurations. Ces états sont traités stochastiquement dans la dynamique et fournissent en moyenne un état corrélé. Nous proposons dans ce travail une reformulation de cette théorie en terme des fonctions d'ondes où les corrélations sont traitées comme des transitions multiples de type particule-trou, limitées aux transitions deux-particules-deux-trous dans notre cas. On applique le schéma obtenu à un modèle unidimensionnel simulant de petites molécules. La capacité de cette théorie à introduire les effets dissipatifs dans le cadre du champ moyen est illustrée à travers plusieurs observables tels que les matrices à un et deux corps, les nombres d'occupation et l'entropie à un corpsQuantum mean field theories represent a robust basis for the description of many dynamical situations from nuclei to molecular systems and clusters. However, the missing of electronic correlations on top of mean field prevents them to give a proper description of the dynamics, in particular dissipative dynamics. Dissipation is intrinsically linked to thermalization which represents the target phenomenon to be described in this thesis. We thus explore a fully quantum mechanical strategy proposed in terms of density matrices in the case of nuclear collisions and which consists in the inclusion of collisional correlations responsible of thermalization in quantum finite systems. This is done by treating two body correlations in time dependent perturbation theory along a certain time span that allows to create an ensemble of pure mean field states for different configurations. These states are used into the dynamics, stochastically, providing in the average one correlated state. We propose in this work a reformulation of this theory in term of wave functions where correlations are translated into multiple particle-hole transitions, restricted to two-particles-two-holes transitions in our case. We apply the obtained scheme to a one dimensional model simulating small molecules. The ability of this theory to include dissipative effects on top of mean field is illustrated through several observables such as the one and two body density matrices, the occupation numbers and the one body entropy
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Swartz, Carol Dorothea. "Integrating environmental sampling and wildlife biomonitoring in exposure and effects assessment: genotoxins at multiple levels of biological organization." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/269.
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Ecotoxicology studies attempt to evaluate the consequences of exposure to environmental contaminants by defining exposure and effects parameters across multiple levels of biological organization. Genetic markers are well-suited for these studies as they can track both somatic and evolutionary effects. In the studies reported here, connections among contaminant levels in environmental media and biota, in vitro bioassay results, and changes in individual- and population-level biomarkers were explored. Sediment and/or wildlife samples were collected from each of three sites of documented environmental contamination, Sumgayit and Baku in the Republic of Azerbaijan and East Fork Poplar Creek in Tennessee. Sumgayit and Baku are heavily contaminated with petroleum and petrochemical wastes. Sediments from several areas and tissues from turtles inhabiting a contaminated wetland contained high levels of several compounds, including mercury, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. Sediment extracts produced variable responses in the Salmonella/microsome mutagenicity assay and did not necessarily reflect contaminant burden. Micronucleus counts in European pond turtles were not statistically different from counts in the same species from an uncontaminated reference site. The counts were statistically correlated with tissue levels of mercury, heptachlor, DDD, hexachlorobenzene, and trans-nonachlor. These results confirmed that Sumgayit and Baku are heavily contaminated with a complex mixture of pollutants and demonstrated that genotoxic effects from exposure to contaminated sediments appear to be slight. East Fork Poplar Creek is a stream that receives contaminant influx from a former Department of Energy nuclear weapons production facility and several point and non-point sources around the city of Oak Ridge, Tennessee. In this study, coefficient of variation in cellular DNA content and randomly amplified polymorphic DNA markers were examined in central stonerollers and compared to previous studies in which the same markers were evaluated in red-breasted sunfish from the same sites. While assay responses were attenuated in stonerollers compared to the sunfish, there is some evidence of genetic damage in both species at the most contaminated sampling site. A common problem in the wildlife studies was high within sample variability combined with small sample size, which most likely masked potential contaminant-induced differences in markers used in these studies.
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Lauzon, M. Louis. "The effects of sampling, reconstruction, and T(2) modulation for polar k-space acquistions in magnetic resonance imaging." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31087.pdf.
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Nekolny, Samantha Ryanne. "The Effects of Sampling Design on Abundance and Distribution of Bottlenose Dolphins in the St. Johns River, Florida." UNF Digital Commons, 2014. http://digitalcommons.unf.edu/etd/541.
Full textAbstract:
The National Oceanic and Atmospheric Administration (NOAA) is tasked with upholding the regulations prescribed in the Marine Mammal Protection Act of 1972. One of the ways this is accomplished is by producing regular stock assessment reports. For these reports, knowledge about a species abundance and distribution is a vital component, allowing informed management decisions to be made that may potentially reduce the natural and anthropogenic impacts on the organisms. In 2010, an Unusual Mortality Event (UME) occurred in the lower St. Johns River, resulting in an unusually large number of bottlenose dolphin strandings. As the data regarding this population was outdated, the cause of the UME could not be positively determined. Consequently, this lack of information provided the impetus to focus research on the individuals within the lower St. Johns River. Chapter one documents the abundance and emigration rates of the bottlenose dolphin population within the St. Johns River in order to provide NOAA with the necessary information to update the stock assessment report for this population. To designate individuals to various stocks, their distribution must first be known. However, many previous home range studies limited the size of the study area surveyed, which resulted in underestimates of the home range sizes. Therefore, in chapter two I investigated the effects that study area size has on the home range estimates of bottlenose dolphins while demonstrating the usefulness of collaborative science. Together these two chapters report data on the bottlenose dolphin population within the St. Johns River that has not been studied in over 16 years and this research also reveals how study design impacts various analyses and perceived outcomes.
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Shin, Hye Sook. "Issues in estimating program effects and studying implementation in large-scale educational experiments the case of a connected classroom technology program /." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1974029271&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Krueger, Kirk L. "Effects of Sampling Sufficiency and Model Selection on Predicting the Occurrence of Stream Fish Species at Large Spatial Extents." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26214.
Full textAbstract:
Knowledge of species occurrence is a prerequisite for efficient and effective conservation and management. Unfortunately, knowledge of species occurrence is usually insufficient, so models that use environmental predictors and species occurrence records are used to predict species occurrence. Predicting the occurrence of stream fishes is often difficult because sampling data insufficiently describe species occurrence and important environmental conditions and predictive models insufficiently describe relations between species and environmental conditions. This dissertation 1) examines the sufficiency of fish species occurrence records at four spatial extents in Virginia, 2) compares modeling methods for predicting stream fish occurrence, and 3) assesses relations between species traits and model prediction characteristics.
The sufficiency of sampling is infrequently addressed at the large spatial extents at which many management and conservation actions take place. In the first chapter of this dissertation I examine factors that determine the sufficiency of sampling to describe stream fish species richness at four spatial extents across Virginia using sampling simulations. Few regions of Virginia are sufficiently sampled, portending difficulty in accurately predicting fish species occurrence in most regions. The sufficient number of samples is often large and varies among regions and spatial scales, but it can be substantially reduced by reducing errors of sampling omission and increasing the spatial coverage of samples.
Many methods are used to predict species occurrence. In the second chapter of this dissertation I compare the accuracy of the predictions of occurrence of seven species in each of three regions using linear discriminant function, generalized linear, classification tree, and artificial neural network statistical models. I also assess the efficacy of stream classification methods for predicting species occurrence. No modeling method proved distinctly superior. Species occurrence data and predictor data quality and quantity limited the success of predictions of stream fish occurrence for all methods. How predictive models are built and applied may be more important than the statistical method used.
The accuracy, generality (transferability), and resolution of predictions of species occurrence vary among species. The ability to anticipate and understand variation in prediction characteristics among species can facilitate the proper application of predictions of species occurrence. In the third chapter of this dissertation I describe some conservation implications of relations between predicted occurrence characteristics and species traits for fishes in the upper Tennessee River drainage. Usually weak relations and variation in the strength and direction of relations among families precludes the accurate prediction of predicted occurrence characteristics. Most predictions of species occurrence have insufficient accuracy and resolution to guide conservation decisions at fine spatial grains. Comparison of my results with alternative model predictions and the results of many models described in peer-reviewed journals suggests that this is a common problem. Predictions of species occurrence should be rigorously assessed and cautiously applied to conservation problems. Collectively, the three chapters of this dissertation demonstrate some important limitations of models that are used to predict species occurrence. Model predictions of species occurrence are often used in lieu of sufficient species occurrence data. However, regardless of the method used to predict species occurrence most predictions have relatively low accuracy, generality and resolution. Model predictions of species occurrence can facilitate management and conservation, but they should be rigorously assessed and applied cautiously.Ph. D.
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El-Nahas, Waleed Mahmoud. "Effects of heating, breathing, hair style, posture, and air velocity on breathing zone concentrations for an anthropometrically-correct manikin in a wind tunnel." Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4274.
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Thesis (Ph. D.)--West Virginia University, 2005.Title from document title page. Document formatted into pages; contains xiv, 256 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 118-122).
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Zhou, Zhiqing. "Effects of Workplace Incivility on Nurses' Emotions, Well-being, and Behaviors: A Longitudinal Study." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5338.
Full textAbstract:
This dissertation used an experience sampling design to examine effects of experienced workplace incivility from three categories of organizational insiders (coworkers, supervisors, and physicians) and from organizational outsiders (patients and their visitors) on targets' emotions, burnout, physical symptoms, and their own uncivil behaviors toward each of the four groups of people. Data were collected from 75 nurses with each nurse responding to online surveys twice per week for 5 consecutive weeks. Results from hierarchical linear modeling showed that within individuals, negative emotions were positively associated with experienced workplace incivility (overall and source-specific), burnout was positively associated with overall workplace incivility and incivility from coworkers, and that physical symptoms were positively associated with experienced workplace incivility from supervisors. In addition, within individuals overall and source-specific experienced workplace incivility all positively predicted targets' own uncivil behaviors correspondingly. None of the proposed moderating effects of three between-person level personality traits (emotional stability, hostile attribution bias, and emotional competence) were supported, and the only significant moderating effect found was that emotional stability moderated the relationship between experienced workplace incivility from- and targets' own uncivil behaviors toward- supervisors was opposite to the prediction. Further, both violence prevention climate and civility climate showed main effects in negatively predicting participants' own uncivil behaviors, but only violence prevention and two of its dimensions (policies and procedures, and pressure for unsafe practices) buffered some of the negative effects of experienced workplace incivility. In summary, the current study found that within individuals experienced workplace incivility had negative effects on targets' emotions, well-being, and behaviors, and that perceived violence prevention climate buffered some of the negative effects.
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Hollinshead, Jack. "Exploring Sport Specialization and Its Effects on Youth Athletes." Wittenberg University Honors Theses / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wuhonors1623854995177177.
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Pettersson, Nicklas. "Multiple Kernel Imputation : A Locally Balanced Real Donor Method." Doctoral thesis, Stockholms universitet, Statistiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-89435.
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We present an algorithm for imputation of incomplete datasets based on Bayesian exchangeability through Pólya sampling. Each (donee) unit with a missing value is imputed multiple times by observed (real) values on units from a donor pool. The donor pools are constructed using auxiliary variables. Several features from kernel estimation are used to counteract unbalances that are due to sparse and bounded data. Three balancing features can be used with only one single continuous auxiliary variable, but an additional fourth feature need, multiple continuous auxiliary variables. They mainly contribute by reducing nonresponse bias. We examine how the donor pool size should be determined, that is the number of potential donors within the pool. External information is shown to be easily incorporated in the imputation algorithm. Our simulation studies show that with a study variable which can be seen as a function of one or two continuous auxiliaries plus residual noise, the method performs as well or almost as well as competing methods when the function is linear, but usually much better when the function is nonlinear.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: In press. Paper 3: Submitted. Paper 4: Submitted.
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Ziajahromi, Shima. "Identification and quantification of microplastics in wastewater treatment plant effluent: Investigation of the fate and biological effects." Thesis, Griffith University, 2018. http://hdl.handle.net/10072/378550.
Full textAbstract:
Microplastics (i.e., plastics particles < 5mm) are widespread emerging contaminants
that have been detected in various aquatic environments worldwide including
freshwater and marine ecosystems. Contamination of the environment with
microplastics has become an environmental issue due to the potential of plastics to
remain for thousands of years and to accumulate in the aquatic environment. The
abundance of microplastics in the aquatic environment is assumed to increase due to
continuous fragmentation of macro and microplastic debris, which can lead to a
decrease in the average size ranges of microplastics over time (Cole et al., 2011).
Moreover, concerns have been raised regarding the potential of microplastics to
physically (e.g., blockage of digestive tract) and chemically (e.g., leaching of sorbed
chemicals and toxic additives) harm aquatic organisms.
Microplastics can enter the aquatic environment from both aquatic-based and landbased
sources. Recently, wastewater treatment plants (WWTP) have been identified
as one of the important land-based sources of microplastics. While microplastics
have been reported in WWTP effluent in Asia, Europe, USA and Russia, little is
known about the presence of microplastics in Australian WWTP effluent. More
importantly, the lack of standardized techniques to sample and characterize
microplastics in environmental samples, especially in complex samples such as
wastewater, has led to inaccurate estimations of microplastic concentrations. In
response to the current knowledge gaps, a novel validated high-volume sampling
device was developed for in situ fractionation of microplastics from wastewater
effluent as part of this project. The developed method was applied to three Australian
WWTPs utilizing primary, secondary and tertiary treatments to provide a snapshot of
the fate and removal of microplastics during various wastewater treatment processes.
To achieve an accurate estimation of microplastics, the sampling technique was
combined with an efficient sample processing method. Microplastic polymer type,
shape and potential origin were further determined using microscopy analysis and
Fourier Transform Infrared (FTIR) spectroscopy. The efficiency of the sampling
device was found to be between 92 to 99% for 500 and 25 μm mesh screens. The
results showed that the concentrations of microplastics were 1.5, 0.6 and 0.2
microplastics per liter of effluent in primary, secondary and tertiary effluent,
respectively. It was also found that the majority of detected microplastics in the
studied WWTPs were polyethylene terephthalate (PET) fibers, which is assumed to
originate from synthetic clothing. Polyethylene (PE) beads and fragments, which may be associated with cosmetic products, were the second most frequently detected
type of microplastic. Despite a thorough sample processing method, FTIR
spectroscopy revealed that between 22 to 90% of the suspected microplastic particles
were in fact non-plastic particles. This study suggests that WWTPs can act as a
significant source of microplastics to the aquatic environment given the large volume
of wastewater discharged to the aquatic environment.
To date, the effects of microplastics on aquatic organisms have mostly been
examined using high and often unrealistic concentrations of microplastics (e.g.,
milligram per liter range). Moreover, while the presence of different types of
microplastics together in aquatic ecosystems has been widely reported, the potential
effects of microplastics when they occur as mixtures are largely unknown. To cover
these knowledge gaps, the potential adverse effects of wastewater-based
microplastics (such as fibers and beads) at lower concentrations on the freshwater
organism Ceriodaphnia dubia were evaluated. The acute (48 h) and chronic (192 h)
effects of PET fibers and PE bead microplastics on C. dubia were assessed alone and
as a binary mixture. The results showed a dose-dependent trend on survival, with C.
dubia more sensitive to PET fibers than PE microplastics. The 48 h EC50 value of
fibers was 1.5 mg/L compared to 2.2 mg/L for PE beads. The binary mixture of
microplastic beads and fibers demonstrated less than additive effects. EC50 values for
the chronic bioassay were 429 μg/L for fibers and 958 μg/L for PE microplastics. A
positive trend of decreasing growth (body size of adults) and reproduction rate
(number of neonates) with increasing microplastic concentration was observed for
both PE and fiber microplastics during the chronic bioassays. Using scanning
electron microscopy (SEM) we observed deformities, such as carapace and antenna
deformation, in C. dubia exposed to fibers at a high concentration, but not at the
lower (environmentally relevant) concentrations.
Given the likelihood that microplastics will eventually sink to the bottom sediment in
the aquatic ecosystem the effects of microplastics were investigated on a freshwater
sediment-dwelling organism (Chironomus tepperi) at environmentally relevant
concentrations of PE microplastics (500 particles/kgsediment). Possible size-dependent
effects of microplastics were also examined using four different size ranges of PE
beads including 1-4, 10-27, 43-54 and 100-126 μm. The results revealed that
exposure to an environmentally relevant concentration of microplastics had a
detrimental impact on the survival, growth (i.e., body length and head capsule) and
emergence of C. tepperi. The observed effects were strongly dependent on microplastic size with C. tepperi more sensitive to microplastics in the size range of
10-27 μm. No negative effects were observed on growth and survival of C. tepperi
exposed to the larger microplastics (100-126 μm), though a significant decrease in
the number of emerging adults was observed in the organisms exposed to the same
size range of microplastics. Further, SEM showed a significant reduction in the size
of the head capsule and antenna in C. tepperi exposed to microplastics in the size
range of 10-27 μm. These results showed that environmentally relevant
concentrations of microplastics in sediment can result in adverse effects on the
development and emergence of C. tepperi, with effects strongly dependent on
particle size.
Finally, we evaluated the effects of PE microplastics on the acute toxicity of a
pyrethroid insecticide (bifenthrin) to midge larvae (C. tepperi) in water. To test the
single and combined effects of bifenthrin and PE microplastics, C. tepperi larvae
were exposed to six concentrations of bifenthrin ranging from 0.1 to 3.2 μg/L in the
presence and absence of microplastics. To examine the possible effects of bifenthrin
and microplastics in synthetic and real water, the bioassays were performed in both
moderately hard water (MHW) and river water. We performed an uptake study using
three different size ranges of microplastics (10-27, 43-54, 100-126 μm) during 8-day
microplastics-spiked water exposure. The results showed that microplastics in the
size range of 10-27 μm were mostly ingested by C. tepperi larvae. Using this finding,
10-27 μm microplastics were selected for the bioassays. The results of the bioassays
using MHW demonstrated a significant decrease in the toxicity of bifenthrin in the
presence of microplastics. This is likely attributable to the tendency of bifenthrin to
bind to the microplastics, which reduces the bioavailability of bifenthrin to midge
larvae. However, in the bioassays conducted in river water with a total organic
carbon (TOC) concentration of 9.6 mg/L, no significant difference was observed
between the toxicity of bifenthrin to C. tepperi in the presence and absence of
microplastics. This is likely due to the interaction between organic carbon and
bifenthrin, which reduces the bioavailability of bifenthrin to C. tepperi larvae.
This thesis highlights that microplastic fibers and beads are released to the aquatic
environment from WWTPs, and that this can negatively affect survival, reproduction
and the life cycle of aquatic organisms (both pelagic and benthic) through
entanglement (fibers) and ingestion (beads). The effect of microplastics on chemical
contaminants is complex, and microplastics may act both as carriers but also as
“chelators” of chemicals in the water, thereby reducing their bioavailability.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Jones, Aaron Michael. "Evaluating the effects of specialty protein sources on nursery pig performance." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38161.
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Doctor of PhilosophyDepartment of Animal Sciences and Industry
Jason C. Woodworth
A total of 6,465 nursery pigs were used in 8 experiments. Experiment 1 investigated the effects of Lactobacillus plantarum (LP) or fermented soybean meal (FSBM) on nursery pig growth performance. A LP × FSBM interaction was detected for G:F, where LP and FSBM individually improved G:F, but the effect was not additive. Experiment 2 evaluated the effects of increasing levels of LP on nursery pig performance. No evidence for differences in growth performance were observed among dietary treatments. Experiment 3 and 4 examined the effects of fish meal source and level on nursery pig growth performance. Overall, a source × level interaction for ADG, G:F and final BW was observed as increasing fish meal source 1 improved ADG and G:F; however, pigs fed fish meal source 2 had improved ADG and G:F at 3%, but decreased at 6%. Pigs fed fish meal source 3 had no further improvements in ADG and G:F beyond the 3% inclusion. No evidence for differences were detected between the dietary treatments for ADFI. Experiment 5 evaluated the effects of feeding fish solubles on nursery pig performance. Pigs fed diets with fish meal had increased ADG and ADFI compared to pigs fed the control diet. There was no evidence for differences in growth performance as fish solubles increased. Experiment 6 and 7 investigated the effects of enzymatically-treated soybean meal (ESBM) on nursery pig performance. Results indicated that nursery pigs fed diets with greater than 9% of ESBM resulted in decreased ADFI and final BW. Experiment 8 evaluated the effects of dietary electrolyte balance (dEB) on nursery pig performance. Increasing dEB in diets from weaning to 21-d after weaning resulted in an increase in ADG and BW, which was the result of a marginally significant improvement in ADFI and G:F. Finally, an experiment was conducted to determine the optimal strategy for collecting and submitting samples that adequately describe the nutrient levels in diets collected from a commercial swine facility. Sampling feeders with a probe resulted in less variability on an individual basis, but seemed to get washed out when individual samples were pooled to form a composite sample.
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Porteous, Anne Catherine. "The effects of relative male attractiveness and costs of choice on the mate sampling behaviour of female zebra finches, Taeniopygia guttata." Thesis, Manchester Metropolitan University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412478.
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Teixeira, Filho Carlos Augusto. "Analysis of the effects of ionospheric sampling of reflection points near-path for high-frequency single-site-location direction finding systems." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA245950.
Full textAbstract:
Thesis (M.S. in Systems Engineeering (Electronic Warfare))--Naval Postgraduate School, December 1990.Thesis Advisor(s): Adler, Richard W. Second Reader: Jauregui, Stephen. "December 1990." Description based on title screen as viewed on March 30, 2010. DTIC Descriptor(s): Ionosphere, Parameters, Electron Density, Ionospheric Disturbances, Theses, Estimates, Sampling, Value, Measurement, Paths. DTIC Identifier(s): Ionospheric Disturbances, Radio Direction Finders, Atmospheric Refraction, Theses. Author(s) subject terms: Single-Site-Location, Direction-Finding, High-Frequency, Estimation, Sampling. Includes bibliographical references (p. 57-58). Also available in print.
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Marinaro, Ralph Michael. "Investigation of water vapor effects on the detection of nitric acid vapor with the tungstic acid technique." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71262.
Full textAbstract:
An automated tungstic acid technique (TAT) has been successfully used to measure gaseous HNO₃ in the presence of water vapor. The TAT is based on the diffusion of gaseous HNO₃ to the interior walls of a tube coated with tungsten VI oxide (WO₃), where it is selectively chemisorbed. The collected HNO₃ sample is thermally desorbed from the WO₃ surface, as NO, and measured by a chemiluminescent oxides of nitrogen analyzer. The integrated analyzer response is directly proportional to the nitric acid collected.
Based on nitric acid hydration characteristics, a decrease in the diffusion coefficient and thus collection efficiency for denuder type measurement techniques may result with increased atmospheric water vapor (i.e., relative humidity). This study emphasizes the effect of water vapor (i.e., relative humidity) as a potential interferent for HNO₃ collection with the TAT system.
The effect of water vapor (< 78% RH) on the collection efficiency for HNO₃ with the tungstic acid technique is negligible at 25°C, but is significant only at elevated sampling temperatures. This threshold effect is further substantiated and eliminated when a modified sampling collection system was designed with coolant capabilities. The new design has been tested to sub-part-per-billion (NOx analyzer detection limit) levels with minimal loss of gaseous HNO₃ signal, thereby increasing sensitivity to atmospheric HNO₃ concentrations and maintaining the gas/aerosol sample integrity.Ph. D.
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Tüchler, Regina, Sylvia Frühwirth-Schnatter, and Thomas Otter. "The Heterogeneity Model and its Special Cases. An Illustrative Comparison." SFB Adaptive Information Systems and Modelling in Economics and Management Science, WU Vienna University of Economics and Business, 2002. http://epub.wu.ac.at/230/1/document.pdf.
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In this paper we carry out fully Bayesian analysis of the general heterogeneity model, which is a mixture of random effects model, and its special cases, the random coefficient model and the latent class model. Our application comes from Conjoint analysis and we are especially interested in what is gained by the general heterogeneity model in comparison to the other two when modeling consumers' heterogeneous preferences. (author's abstract)Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"
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Yilmaz, Civan Mihriban. "Spatial Distribution Of Organic Pollutants In Bursa Atmosphere: Seasonality And Health Effects." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611686/index.pdf.
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The assessment of volatile organic compounds (VOCs) has become an area of particular interest in the field of atmospheric pollution due to their adverse health and environmental effects. This study is aimed to identify, quantify and characterize VOC in different urban areas and industrial areas in Bursa. The spatial distribution, seasonal variation as well as health risks assessment of VOC were discussed. Air samples were collected by means of sorbent passive sampling at over 50 sampling points in Bursa and analyzed by GC-thermal desorption. A total of seven weekly measurement periods were completed across the city center from 2005 to 2007. The source of VOC was apportioned with the commonly used receptor model, namely Factor Analysis. Motor vehicles and industrial solvent usage are the most abundant VOC sources to contribute to urban atmosphere in Bursa, 63% and 20%, respectively. The health risks of VOC were also evaluated. The questionnaire was filled out by selected people living in Bursa to obtain time-activity pattern for health risk assessment. Lifetime cancer risks were estimated with the measured VOC data. All the statistical parameters used to represent cancer risks for the selected compounds exceeded the stated level. Benzene had the highest adverse health effect among these compounds according to USEPA (2009) calculation with the mean cancer risk 3x10-4.
In addition to intensive field sampling campaigns conducted in Bursa, the VOC measurement were completed for a period of six months to evaluate uptake rate of VOC in Ankara. Uptake rate equations depending on relative humidity and wind speed were developed for 25 VOCs.
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Bayindir, Elif. "Investigation Of Passive Sampling Of No2 And O3 In Ambient Air And Determination Of The Effects Of Meteorological Parameters To The Uptake Rate." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610299/index.pdf.
Full textAbstract:
In this study NO2 and O3 gases which are the secondary pollutants in ambient air were sampled with designed passive tubes. The collected samples were extracted for UV-VIS spectrometric analysis. NO2 gases were converted to NO2- ions by extracting with water and then this solution was colored with Saltzman reagent (5:1 sulfanilamide and N-(1 naphthly)-ethlyene-diamine dihydrochloride). Then the absorbance of the solution was measured at 537 nm. O3 was extracted with 3-metyl-2-benzothiazolinone hydrozone hydrochloride solution which gives yellow color after extraction. The absorbance of the solution was measured at 430 nm.
Before starting the experiment, the exposure time was optimized. For this purpose, 15 days in winter and 65 days in summer samplings were conducted. For both NO2 and O3 it was decided that 7 days of sampling period was required as an optimum sampling time in order to reach maximum collection efficiency values for both pollutants.
To determine the uptake rates of the passive tubes, NO2 was sampled in fifteen weeks and O3 was sampled in thirteen weeks. During each sampling period passive tubes were placed nearby the active air sampling stations of Refik Saydam Hygiene Center, Air Quality Control and Research Laboratory in Ulus and Keçiö
ren. Then uptake rates of NO2 and O3 passive tubes were determined by comparing passive and active sampler data. The uptake rate was calculated for NO2 and O3 as 0.91 x 103 cm3 h-1 and 1.71 x 103, respectively. Since sampling was done in ambient air the effect of meteorological parameters should be determined. Each meteorological parameters, wind speed, wind direction, relative humidity, temperature, pressure and solar ration were correlated with uptake rates. It was found out that none of these parameters had a significant effect on NO2 passive tube uptake rate. However, O3 passive tubes were affected from temperature, solar radiation and relative humidity. Temperature and solar radiation showed positive correlation with uptake rate, on the contrary, relative humidity was inversely correlated with uptake rate. Finally the pollution map of Ankara was created by taking samples from forty points in the city.