Effective Sampling Method Research Articles

Endoscopic Ultrasound-Guided Fine Needle Aspiration in Hollow Viscus Cancer

Accurate cancer staging is essential in patients with hollow viscus malignancy to decide therapeutic modalities. Endoscopic ultrasound (EUS) is considered as the best modality for local staging of hollow viscus cancer. EUS-guided fine needle aspiration (FNA) is a minimally invasive and effective sampling method. EUS-FNA should be applied when positive diagnosis of malignancy can possibly change the choice of therapeutic options. EUS in conjunction with EUS-FNA can optimize stage-directed therapy which is helpful in selecting minimally invasive treatment option including endoscopic treatment and avoiding unnecessary surgery in advanced cases.

A Comparison of Larval Fish Sampling Methods for Tropical Streams

AbstractAssessment of early life history characteristics requires effective sampling methods for larval fishes. Different gears are suitable for different habitats and frequently select different sizes or life history stages. In this study, two passive sampling methods were compared for use in collecting larval freshwater and estuarine fishes in two tropical streams. Drift nets and light traps were identified a priori as the most appropriate gears for sampling in these systems based on stream characteristics (including accessibility, size, and morphology). Catches were compared between sampling methods. Additionally, catches under different environmental conditions (flow, tide stage, and moon phase), during different sampling periods (time of day and week of summer), and at different depths were compared using mixed‐effects analysis of variance. A total of 2,156 fish were captured in 954 h of sampling. The significant (α < 0.05) explanatory variables for total larval catch were stream, sampling method, week of summer, time of day, and moon phase. Eleven families were represented in the samples, with the families Gobiidae (n = 948), Eleotridae (n = 391), and Syngnathidae (n = 276) comprising 94.9% of the identifiable larvae collected. The variables that explained both the Gobiidae and Syngnathidae catches were gear, week of summer, and time of day. The Syngnathidae catch was highest in drift nets, but the Gobiidae catch was highest in light traps. Nighttime light trap sampling appeared to be the best overall technique for larval collection in these systems. However, a combination of light traps and drift nets would reduce the biases associated with size and species selectivity found for individual gears, and this approach would be preferable for sampling small tropical streams.Received January 26, 2011; accepted October 5, 2011

Assessing the effects of geomorphological processes on archaeological densities: a GIS case study on Zakynthos Island, Greece

While geomorphological processes are considered key factors in the distribution of archaeological surface finds, few studies have attempted to quantify the relationship between artefact dispersal and erosional/depositional patterns. This paper compares Unit Stream Power Erosion Deposition model (USPED) and Revised Universal Soil Loss Equation (RUSLE) and integrates the results in the archaeological finds’ density map of Zakynthos Archaeological Project. The study area (Palaiokastro), with artefacts dated from middle Paleolithic to medieval times, includes a steep terrain with a surrounding plain area, where the downslope erosion has considerably modified the distribution of archaeological remains. Through this study, it is possible to identify relationships between high artefact densities and stable/non-eroded surfaces, and on the other hand, low densities and eroded surfaces. However, the results indicate a degree of spatial variability, which modifies the predicted relationship. The consideration of the effects of these temporal and spatial patterns is crucial for developing effective sampling methods and accurately interpreting the archaeological record.

풍력발전을 포함한 시스템의 발전량 적정성 평가를 위한 비순차 샘플링 방법

This paper presents a novel random sampling method for generation adequacy assessment including wind-power. Although a time sequential sampling has advantages than a random sampling in its assessment results, it takes long assessment time. Therefore, an effective random sampling method for generation adequacy assessment is highly recommended to get specific reliability indices quickly. The proposed method is based on the Monte-Carlo simulation with state sampling and it can be applied to generation adequacy assessment with other intermittent power sources.

Dengue Control: The Challenge Ahead

Dengue Control: The Challenge Ahead

Dynamic adsorption of diarrhetic shellfish poisoning (DSP) toxins in passive sampling relates to pore size distribution of aromatic adsorbent

Solid-phase adsorption toxin tracking (SPATT) technology was developed as an effective passive sampling method for dissolved diarrhetic shellfish poisoning (DSP) toxins in seawater. HP20 and SP700 resins have been reported as preferred adsorption substrates for lipophilic algal toxins and are recommended for use in SPATT testing. However, information on the mechanism of passive adsorption by these polymeric resins is still limited. Described herein is a study on the adsorption of OA and DTX1 toxins extracted from Prorocentrum lima algae by HP20 and SP700 resins. The pore size distribution of the adsorbents was characterized by a nitrogen adsorption method to determine the relationship between adsorption and resin porosity. The Freundlich equation constant showed that the difference in adsorption capacity for OA and DTX1 toxins was not determined by specific surface area, but by the pore size distribution in particular, with micropores playing an especially important role. Additionally, it was found that differences in affinity between OA and DTX1 for aromatic resins were as a result of polarity discrepancies due to DTX1 having an additional methyl moiety.

Quantitative Assessment of Yield, Precision, and Cost-Effectiveness of Three Wetland Invertebrate Sampling Techniques

Macroinvertebrates are increasingly used as indicators of wetland integrity and productivity. However, accurate interpretation of biological information depends on effective sampling methods, which are also preferably cost-effective. We compared sampling yield, precision, and cost-effectiveness of two traditional wetland sampling methods (dipnet, stove pipe corer) to a dipnet combined with a dropframe in wetlands in the Platte River Valley, USA. The dropframe method was designed to be more quantitative than standard dipnet techniques and to maximize capture of mobile taxa. We compared measures of macroinvertebrate community structure (e.g., abundance, richness, diversity) and function (functional structure, habitat associations), as well as processing time for each sampling technique in vegetated and non-vegetated habitats. Vegetated habitats harbored higher richness, diversity, abundance, and biomass of most invertebrates. The dipnet consistently yielded the lowest values in vegetated and non-vegetated habitats, suggesting that sampling with a dipnet alone can greatly underestimate macroinvertebrate populations and diversity. The corer and the dropframe yielded similar results, but the dropframe produced significantly higher richness values. While the dropframe appeared to be a good choice for sampling in these wetlands, sample processing times for this method were more than two times longer than the other methods. Results provide a basis for informed decisions regarding quantitative sampling of wetland macroinvertebrates.

Reduced Basis Approximation and Error Bounds for Potential Flows in Parametrized Geometries

AbstractIn this paper we consider (hierarchical, Lagrange) reduced basis approximation anda posteriorierror estimation for potential flows in affinely parametrized geometries. We review the essential ingredients: i) a Galerkin projection onto a low-dimensional space associated with a smooth “parametric manifold” in order to get a dimension reduction; ii) an efficient and effective greedy sampling method for identification of optimal and numerically stable approximations to have a rapid convergence; iii) ana posteriorierror estimation procedure: rigorous and sharp bounds for the linear-functional outputs of interest and over the potential solution or related quantities of interest like velocity and / or pressure; iv) an Offline-Online computational decomposition strategies to achieve a minimummarginal computational costfor high performance in the real-time and many-query (e.g., design and optimization) contexts. We present three illustrative results for inviscid potential flows in parametrized geometries representing a Venturi channel, a circular bend and an added mass problem.

家庭どうぶつ医療における保険金支払いデータの活用

Anicom, the leading pet insurer in Japan started its operation 12 years ago, and currently holds almost 400,000 pet insurance policies in force. Insurance claim data could provide epidemiological information. We tried to investigate the prevalence of disease with analysis of the above data. All insurance claim data of 217,150 dogs (male 115,192 and female101,958) contracted with Anicom pet insurance from April 1 2008 to March 31 2009 were used for the research. The high incidence of insured dogs in Japan is 20.9% in Ear Diseases, 19.7% in Dermatologic Diseases, and 15.6%in Gastrointestinal Diseases. The incidence of foreign body ingestion was significantly different; 3.7% in puppies under one year of age, 2.2% in 1 year old, and under 1.4% in 3-10 years old. It is considered that the pet insurance data would provide the tendency of disease in dogs. Further, it will be required to develop effective sampling methods for more valuable data to research on the better treatments and prevention of animal diseases.

Sequential sampling plans for estimating density of glassy-winged sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae) on citrus

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), is a serious pest of grapes and other crop and ornamental plants mainly through its role as a vector of the bacterium Xylella fastidiosa Wells. Citrus harbors large populations of this insect throughout much of the year in areas where the pest is problematic and improved understanding of the population dynamics and management of H. vitripennis on citrus may be key to its management in the broader agricultural landscape. In turn, the study of population dynamics and the development of management strategies require effective and efficient sampling methods. Within-tree sampling distribution studies revealed that adults and nymphs were more abundant and less variable in the upper strata of citrus trees (>1.5 m). They occurred in greater numbers on the southern quadrants of trees but relative variability did not differ due to cardinal direction. We developed and validated several fixed-precision sequential sampling plans for estimating the density of nymphs and adults of H. vitripennis using a pole bucket sampling method. Based on validation from resampling of independent data sets, Green’s sequential sampling model, based on the Taylor’s power law, provided the best overall performance in terms of providing mean density estimates with levels of precision equal to or better than the desired precision over a range of possible insect densities. Average sampling costs varied from about 21 to 189 min for a desired precision of 0.25 depending on insect density and whether the goal is to sample nymphs, adults or both stages combined. Further, the sampling plans developed on orange trees were robust, being equally effective on orange and lemon trees and on trees treated or not with insecticides.

Choosing a suitable sample size in descriptive sampling

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.

An empirical analysis of engineers' information behaviors

AbstractThe importance of the acquisition and provision of information within knowledge work such as engineering is widely acknowledged. This article reports an extensive empirical study of such information behaviors in engineers, using a novel and effective work sampling method. Seventy‐eight design engineers each carried a portable handheld computer (PDA) for 20 working days. Once every hour, they were prompted to enter data concerning the task they were currently performing, including the information behaviors in which they were engaging. The resultant data represent a comprehensive picture of engineers' information behaviors and the percentage of their working time for which each of these behaviors accounts (55.75% in total). Specific hypotheses concerning the time spent engaged in these behaviors were also tested. Accordingly, it was found that participants spent substantially more time receiving information they had not requested than information they had, and this pattern was also reflected when they provided others with information. Furthermore, although there was no difference found between the time participants spent searching for information from other people compared with nonhuman sources, in the former case they spent relatively less time locating the information source and information within that source, and relatively more time engaged in problem solving and decision making. The results are discussed in terms of their implications for theory and organizational practice.

An adaptive sampling scheme guided by BART—with an application to predict processor performance

AbstractThe evaluation of new processor designs is an important issue in electrical and computer engineering. Architects use simulations to evaluate designs and to understand trade‐offs and interactions among design parameters. However, due to the lengthy simulation time and limited resources, it is often practically impossible to simulate a full factorial design space. Effective sampling methods and predictive models are required. In this paper, the authors propose an automated performance predictive approach which employs an adaptive sampling scheme that interactively works with the predictive model to select samples for simulation. These samples are then used to build Bayesian additive regression trees, which in turn are used to predict the whole design space. Both real data analysis and simulation studies show that the method is effective in that, though sampling at very few design points, it generates highly accurate predictions on the unsampled points. Furthermore, the proposed model provides quantitative interpretation tools with which investigators can efficiently tune design parameters in order to improve processor performance. The Canadian Journal of Statistics 38: 136–152; 2010 © 2010 Statistical Society of Canada

Effectiveness of pitfall trapping, Winkler and Berlese extraction methods for sampling ground-dwelling coleoptera in tropical montane cloud forests

The evaluation of extraction efficiency of the widely employed sampling methods for the extraction of ground-dwelling Coleoptera indicate that pitfall traps tend to overestimate large Coleoptera whereas the quadrate extraction methods (Berlese and Winkler extraction methods) entrap small ones. In a quest for the most effective sampling method for ground dwelling Coleoptera in a tropical montane evergreen forest in the Western Ghats, the efficiency of pitfall trap, Berlese and Winkler extraction methods were evaluated. Results showed that pitfall trap addressed the active beetles groups (Carabidae, Chrysomelidae, Leiodidae, Ptiliidae, Scydmaenidae and Staphylinidae) while quadrate extraction methods captured more of the beetles associated with moisture and sheltered areas (Curculionidae, Histeridae, Hydraenidae and Latridiidae). When cost and time constraints limit the sampling, the Berlese extraction method is the best single quantitative sampling method and pitfall trap is ideal for qualitative estimates. When thoroughness at the cost of time and labour costs is permissible, a combination of pitfall trap with Berlese extraction enables an effective qualitative and quantitative estimation, and better faunal inventory studies. Also, a combination of Berlese method followed by floatation extraction towards the under-sampled families will enable cost effective and comprehensive sampling.

Within-tree distribution and attractant sampling of propagative pinewood nematode, Bursaphelenchus xylophilus: An early diagnosis approach

Early detection is of primary importance to enable rapid actions to prevent the spread and introduction of invasive species. The pinewood nematode (PWN), Bursaphelenchus xylophilus, a serious invasive and destructive species, is listed as a quarantine pest in the legislation of more than 40 countries. However, Baermann funnel extractions of wood from discs cut from trees at breast-height often do not detect the presence of PWN in infested trees. A serious consequence of such false negatives is the loss of the best window for implementation of eradication or quarantine measures to prevent establishment of incipient PWN infestations. Here we document the within-tree horizontal and vertical distribution of PWN in infested stands in China, using a newly developed kairomonal trapping technique. Our results provide a simple, effective, rapid and non-destructive sampling method that takes into account the changes of PWN within-tree distribution in relation to pine wilt disease (PWD) symptom development. When 60–80% of the foliage has become pale green, PWN is recovered from larger diameter branches. As disease symptoms progress, PWN moves into and down the trunk. As the needles turn yellow, PWN was recovered from the trunk at 1–2 m above the ground. The correlation between the within-tree distribution of PWN and the expression of symptoms indicated a strong association between the distribution of PWN and physiological and pathological changes that develop in attacked pines through the interaction between PWN and tree. This systematic sampling technique takes into account the within-tree distribution of the nematode and should greatly enhance early detection of PWN in field surveys, monitoring and phytosanitary inspections.

Sampling and analytical variability associated with the determination of aflatoxins and ochratoxin A in bulk lots of powdered ginger marketed in 1-lb bags.

Ginger has been used as a food, dietary supplement, and condiment for centuries. Mycotoxins such as the aflatoxins (AF) and ochratoxin A (OTA) have been reported in ginger roots in several studies. It is important to design effective sampling methods that will accurately and precisely predict the true mycotoxin level in a bulk lot. The objective of this study was to measure the sampling and analytical variability associated with the test procedure used to measure AF and OTA in a bulk lot of powdered ginger using a 5-g laboratory sample and HPLC analytical methods. Twelve 5-g laboratory samples were taken from each of two lots. Duplicate aliquots were removed from each 5-g laboratory sample/solvent blend, and each aliquot was simultaneously analyzed for AF and OTA by HPLC analytical methods. Using a balanced nested design, the total variance associated with the above AF and OTA test procedures was partitioned into sampling and analytical variance components for each lot. Averaged across both lots, the sampling and analytical variances accounted for 87% and 13% of the total variance, respectively, for AF and 97% and 3%, respectively, for OTA. The sampling and analytical coefficients of variation were 9.5% and 3.6%, respectively, for AF, and 16.6% and 2.9%, respectively, for OTA when using a single 5-g laboratory sample and HPLC analytical methods. Equations are derived to show the effect of increasing laboratory sample size and/or number of aliquots on reducing the variability of the test procedures used to estimate OTA and AF in powdered ginger.

An effective sampling method for decision trees considering comprehensibility and accuracy

Because the target domain of data mining using decision trees usually contains a lot of data, sampling is needed. But selecting proper samples for a given decision tree algorithm is not easy, becau...

The Effective Sampling Method of Electron Energy Distributions using the Higher Order Sampling and Spline Function

A novel method for sampling electron energy distribution with good statistics in Monte Carlo simulation(MCS) using the Higher Order Sampling and spline function is developed. Electron energy distributions f(e) obtained by the developed method, are in excellent agreement with those obtained by conventional sampling method in equilibrium and non-equilibrium regions. The sampling method is extended to two dimensional, and applied to the sampling of spatial variation of energy distribution f(e, x) of Steady State Townsend experiment. The obtained energy distributions are good agreement with those by conventional method. It is found that traced electron number in MCS can be reduced to 1/10 of the conventional method by using the developed sampling method.

Comparative Evaluation of Methods Used for Sampling Malaria Vectors in the Kilombero Valley, South Eastern Tanzania

To monitor malaria transmission, effective sampling methods for host seeking vectors are necessary. The suit- ability of these methods can be determined by field measurements of their trapping efficiencies. We compared the effi- ciencies of the Human Landing Catch (HLC), the Centers for Disease Control light trap (CDC-LT) placed next to occu- pied bednets and the Mbita trap for sampling Anopheles gambiae s.l and Anopheles funestus. The sampling methods were rotated through three houses, each with a human bait, for 8 cycles in a 3 x 3 Latin-square design. Relative to the HLC, the efficiency (and 95% c. i) of the CDC-LT for sampling An. gambiae s.l. was 0.331 (0.237 - 0.460) while that for Mbita trap was 0.031 (0.013 - 0.077). For An. funestus however, the sampling efficiencies were 0.818 (0.611 - 1.096) and 0.022 (0.003-0.165) respectively. We conclude that both the CDC-LT placed next to an occupied bednet and the Mbita trap are less efficient than HLC, the latter being evidently unsuitable for use in the Kilombero Valley.

Reduced Basis Approximation and a Posteriori Error Estimation for Affinely Parametrized Elliptic Coercive Partial Differential Equations

In this paper we consider (hierarchical, Lagrange) reduced basis approximation and a posteriori error estimation for linear functional outputs of affinely parametrized elliptic coercive partial differential equations. The essential ingredients are (primal-dual) Galerkin projection onto a low-dimensional space associated with a smooth “parametric manifold”—dimension reduction; efficient and effective greedy sampling methods for identification of optimal and numerically stable approximations—rapid convergence; a posteriori error estimation procedures—rigorous and sharp bounds for the linear-functional outputs of interest; and Offline-Online computational decomposition strategies—minimum marginal cost for high performance in the real-time/embedded (e.g., parameter-estimation, control) and many-query (e.g., design optimization, multi-model/scale) contexts. We present illustrative results for heat conduction and convection-diffusion, inviscid flow, and linear elasticity; outputs include transport rates, added mass, and stress intensity factors.