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Segmentation
Kinds of Segmentation Terms modified by Segmentation Selected AbstractsSEGMENTATION OF BEEF JOINT IMAGES USING HISTOGRAM THRESHOLDINGJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2006CHAOXIN ZHENG ABSTRACT Four histogram-based thresholding methods, i.e., one-dimensional (1-D) histogram variance, 1-D histogram entropy, two-dimensional (2-D) histogram variance and 2-D histogram entropy, were proposed to segment the images of beef joints (raw, cooked and cooled) automatically from the background. The 2-D histogram-based methods incorporate a fast algorithm to reduce the calculation time, thus increasing the speed greatly. All the four methods were applied to 15 beef joint images captured from a video camera, and the methods including pixel classification, object overlap and object contrast for the evaluation of segmentation results were then employed to compare the performances or the abilities of the four different segmenting methods. Results indicate that the 2-D histogram variance thresholding method can accomplish the segmentation task with the most satisfactory performance. [source] VARIABILITY IN HEDONICS: INDICATIONS OF WORLD-WIDE SENSORY AND COGNITIVE PREFERENCE SEGMENTATIONJOURNAL OF SENSORY STUDIES, Issue 3 2000HOWARD R. MOSKOWITZ ABSTRACT This paper approaches inter-individual differences in the hedonics of food products as an indication of the existence of different groups of people with different likes and dislikes. Rather than considering the differences as an unpleasant fact of nature, to be ignored, the paper shows how these differences point to segments of consumers in the population. These segments enable the product developer to create different types of food products, in order to satisfy the different tastes. The paper, presenting an algorithm for segmentation of individuals into different groups, results from three studies with foods, and the extension of the particular segmentation algorithm into concepts (with three additional studies). The paper presents both new data and results from previously published research. These data are presented in a case history format. [source] A Data-driven Segmentation for the Shoulder ComplexCOMPUTER GRAPHICS FORUM, Issue 2 2010Q Youn Hong Abstract The human shoulder complex is perhaps the most complicated joint in the human body being comprised of a set of three bones, muscles, tendons, and ligaments. Despite this anatomical complexity, computer graphics models for motion capture most often represent this joint as a simple ball and socket. In this paper, we present a method to determine a shoulder skeletal model that, when combined with standard skinning algorithms, generates a more visually pleasing animation that is a closer approximation to the actual skin deformations of the human body. We use a data-driven approach and collect ground truth skin deformation data with an optical motion capture system with a large number of markers (200 markers on the shoulder complex alone). We cluster these markers during movement sequences and discover that adding one extra joint around the shoulder improves the resulting animation qualitatively and quantitatively yielding a marker set of approximately 70 markers for the complete skeleton. We demonstrate the effectiveness of our skeletal model by comparing it with ground truth data as well as with recorded video. We show its practicality by integrating it with the conventional rendering/animation pipeline. [source] Interactive Visualization of Function Fields by Range-Space SegmentationCOMPUTER GRAPHICS FORUM, Issue 3 2009John C. Anderson Abstract We present a dimension reduction and feature extraction method for the visualization and analysis of function field data. Function fields are a class of high-dimensional, multi-variate data in which data samples are one-dimensional scalar functions. Our approach focuses upon the creation of high-dimensional range-space segmentations, from which we can generate meaningful visualizations and extract separating surfaces between features. We demonstrate our approach on high-dimensional spectral imagery, and particulate pollution data from air quality simulations. [source] 3D Image Segmentation of Aggregates from Laser ProfilingCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2003Hyoungkwan Kim Automated scanners of different designs use cameras or lasers to obtain digital images of groups of aggregate particles. To accurately determine particle size and shape parameters, each particle region in the image must be isolated and processed individually. Here, a method for segmenting a particle image acquired from laser profiling is developed using a Canny edge detector and a watershed transformation. Canny edges with rigorous and liberal threshold values are used to outline particle boundaries on a binary image and to check the validity of watersheds, respectively. To find appropriate regional minima in the watershed transformation, a varying search window method is used, where the number of neighboring pixels being compared with the pixel of interest is determined from the height value of the pixel. Test results with this method are promising. When implemented in automated systems that are designed to rapidly assess size and shape characteristics of stone particles, this technique can not only reduce the amount of time required for aggregate preparation, but also increase the accuracy of analysis results. [source] From segment to somite: Segmentation to epithelialization analyzed within quantitative frameworksDEVELOPMENTAL DYNAMICS, Issue 6 2007Paul M. Kulesa Abstract One of the most visually striking patterns in the early developing embryo is somite segmentation. Somites form as repeated, periodic structures in pairs along nearly the entire caudal vertebrate axis. The morphological process involves short- and long-range signals that drive cell rearrangements and cell shaping to create discrete, epithelialized segments. Key to developing novel strategies to prevent somite birth defects that involve axial bone and skeletal muscle development is understanding how the molecular choreography is coordinated across multiple spatial scales and in a repeating temporal manner. Mathematical models have emerged as useful tools to integrate spatiotemporal data and simulate model mechanisms to provide unique insights into somite pattern formation. In this short review, we present two quantitative frameworks that address the morphogenesis from segment to somite and discuss recent data of segmentation and epithelialization. Developmental Dynamics 236:1392,1402, 2007. © 2007 Wiley-Liss, Inc. [source] Analysis of pattern precision shows that Drosophila segmentation develops substantial independence from gradients of maternal gene productsDEVELOPMENTAL DYNAMICS, Issue 11 2006David M. Holloway Abstract We analyze the relation between maternal gradients and segmentation in Drosophila, by quantifying spatial precision in protein patterns. Segmentation is first seen in the striped expression patterns of the pair-rule genes, such as even-skipped (eve). We compare positional precision between Eve and the maternal gradients of Bicoid (Bcd) and Caudal (Cad) proteins, showing that Eve position could be initially specified by the maternal protein concentrations but that these do not have the precision to specify the mature striped pattern of Eve. By using spatial trends, we avoid possible complications in measuring single boundary precision (e.g., gap gene patterns) and can follow how precision changes in time. During nuclear cleavage cycles 13 and 14, we find that Eve becomes increasingly correlated with egg length, whereas Bcd does not. This finding suggests that the change in precision is part of a separation of segmentation from an absolute spatial measure, established by the maternal gradients, to one precise in relative (percent egg length) units. Developmental Dynamics 235:2949,2960, 2006. © 2006 Wiley-Liss, Inc. [source] Effects of Market Segmentation and Bank Concentration on Mutual Fund Expenses and Returns: Evidence from FinlandEUROPEAN FINANCIAL MANAGEMENT, Issue 3 2004Timo P. Korkeamaki G15; G18; G20 Abstract A tremendous amount of research examines US mutual funds, but fund markets also thrive in other countries. However, research about these fast growing markets is lacking. This study addresses Finnish funds. Fast growth of the Finnish fund industry, strong bank dominance in the industry and recent EU membership make it an interesting market to examine. The Finnish fund market is also of particular interest since it had the fastest growth among the EU countries during 1996,2000. We find evidence that bank-managed and older funds charge higher expenses but investors are not compensated for paying higher expenses with higher risk-adjusted returns, suggesting a potential agency problem. Overall, Finnish fund expenses have decreased over time, consistent with EU membership reducing market segmentation and generating competition. [source] Market Segmentation and Information Asymmetry in Chinese Stock Markets: A VAR AnalysisFINANCIAL REVIEW, Issue 4 2003Jian Yang G15/G32 Abstract This study examines the market segmentation and information asymmetry patterns in Chinese stock markets. The recursive cointegration analysis confirms that each of six markets is not linked with other markets in the long run. Further, the result from data-determined forecast error variance decomposition clearly shows that foreign investors in the Shanghai B-share market are better informed than Chinese domestic investors in two A-share markets and foreign investors in Shenzhen and Hong Kong markets over time. The finding challenges a widespread assumption of less informed foreign investors in the literature, but suggests that foreign investors could be more informed in emerging markets. [source] Risk Segmentation Related to the Offering of a Consumer-Directed Health Plan: A Case Study of Humana Inc.HEALTH SERVICES RESEARCH, Issue 4p2 2004Laura A. Tollen Objective. To determine whether the offering of a consumer-directed health plan (CDHP) is likely to cause risk segmentation in an employer group. Study Setting and Data Source. The study population comprises the approximately 10,000 people (employees and dependents) enrolled as members of the employee health benefit program of Humana Inc. at its headquarters in Louisville, Kentucky, during the benefit years starting July 1, 2000, and July 1, 2001. This analysis is based on primary collection of claims, enrollment, and employment data for those employees and dependents. Study Design. This is a case study of the experience of a single employer in offering two consumer-directed health plan options ("Coverage First 1" and "Coverage First 2") to its employees. We assessed the risk profile of those choosing the Coverage First plans and those remaining in more traditional health maintenance organization (HMO) and preferred provider organization (PPO) coverage. Risk was measured using prior claims (in dollars per member per month), prior utilization (admissions/1,000; average length of stay; prescriptions/1,000; physician office visit services/1,000), a pharmacy-based risk assessment tool (developed by Ingenix), and demographics. Data Collection/Extraction Methods. Complete claims and administrative data were provided by Humana Inc. for the two-year study period. Unique identifiers enabled us to track subscribers' individual enrollment and utilization over this period. Principal Findings. Based on demographic data alone, there did not appear to be a difference in the risk profiles of those choosing versus not choosing Coverage First. However, based on prior claims and prior use data, it appeared that those who chose Coverage First were healthier than those electing to remain in more traditional coverage. For each of five services, prior-year usage by people who subsequently enrolled in Coverage First 1 (CF1) was below 60 percent of the average for the whole group. Hospital and maternity admissions per thousand were less than 30 percent of the overall average; length of stay per hospital admission, physician office services per thousand, and prescriptions per thousand were all between 50 and 60 percent of the overall average. Coverage First 2 (CF2) subscribers' prior use of services was somewhat higher than CF1 subscribers', but it was still below average in every category. As with prior use, prior claims data indicated that Coverage First subscribers were healthier than average, with prior total claims less than 50 percent of average. Conclusions. In this case, the offering of high-deductible or consumer-directed health plan options alongside more traditional options caused risk segmentation within an employer group. The extent to which these findings are applicable to other cases will depend on many factors, including the employer premium contribution policies and employees' perception of the value of the various plan options. Further research is needed to determine whether risk segmentation will worsen in future years for this employer and if so, whether it will cause premiums for more traditional health plans to increase. [source] Segmentation of broadcasted baseball videos into every inning and plate appearanceIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2006Koji Abe Non-member No abstract is available for this article. [source] Clause Segmentation by 6-Month-Old Infants: A Crosslinguistic PerspectiveINFANCY, Issue 5 2008Elizabeth K. Johnson Each clause and phrase boundary necessarily aligns with a word boundary. Thus, infants' attention to the edges of clauses and phrases may help them learn some of the language-specific cues defining word boundaries. Attention to prosodically well-formed clauses and phrases may also help infants begin to extract information important for learning the grammatical structure of their language. Despite the potentially important role that the perception of large prosodic units may play in early language acquisition, there has been little work investigating the extraction of these units from fluent speech by infants learning languages other than English. We report 2 experiments investigating Dutch learners' clause segmentation abilities. In these studies, Dutch-learning 6-month-olds readily extract clauses from speech. However, Dutch learners differ from English learners in that they seem to be more reliant on pauses to detect clause boundaries. Two closely related explanations for this finding are considered, both of which stem from the acoustic differences in clause boundary realizations in Dutch versus English. [source] Overcoming the Effects of Variation in Infant Speech Segmentation: Influences of Word FamiliarityINFANCY, Issue 1 2008Leher Singh Previous studies have shown that 7.5-month-olds can track and encode words in fluent speech, but they fail to equate instances of a word that contrast in talker gender, vocal affect, and fundamental frequency. By 10.5 months, they succeed at generalizing across such variability, marking a clear transition period during which infants' word recognition skills become qualitatively more mature. Here we explore the role of word familiarity in this critical transition and, in particular, whether words that occur frequently in a child's listening environment (i.e., "Mommy" and "Daddy") are more easily recognized when they differ in surface characteristics than those that infants have not previously encountered (termed nonwords). Results demonstrate that words are segmented from continuous speech in a more linguistically mature fashion than nonwords at 7.5 months, but at 10.5 months, both words and nonwords are segmented in a relatively mature fashion. These findings suggest that early word recognition is facilitated in cases where infants have had significant exposure to items, but at later stages, infants are able to segment items regardless of their presumed familiarity. [source] Segmentation and classification of biological cell images by a multifractal approachINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 6 2003N. Lassouaoui Recently, the clinical role of image processing has been developed considerably. The resources of this new technology were exploited for the needs of doctors in their practice. In this study, we propose a computer vision for tracking the uterine collar cancer. Here, we present three stages: preprocessing, segmentation, and classification. The segmentation stage uses a multifractal algorithm based on the computation of the singularity exponents; its role is separating each cell on its core and its cytoplasm, which permits the analysis of each one in the recognition stage for deducing a response about the malignity of the cell. However, the classification is performed by an algorithm of area growth. Knowing that there are four layers in the epithelium, the classification allows for learning the type of each cell in an image for organizing the research in the recognition stage. Thus, we contribute to the creation of a database for the recognition stage. This base contains the core and cytoplasm images with information about the type of each cell. Promising results were obtained with a short execution time that permits the start of the recognition stage. © 2003 Wiley Periodicals, Inc. [source] Image Segmentation and Bruise Identification on Potatoes Using a Kohonen's Self-Organizing MapJOURNAL OF FOOD SCIENCE, Issue 7 2005Thierry Marique ABSTRACT: Potato quality includes a low incidence of colored bruises resulting from bad storage or manipulation practices. We developed a procedure to process and segment potato images by using Kohonen's self-organizing map. Anomalous regions could be distinguished on 3 potato varieties. Bruises that were very dissimilar in appearance were correctly identified, and some particular defects such as green spots could be located as well. [source] Global Market Segmentation and Patterns in Stock Market Reaction to US Earnings Announcements: Further EvidenceJOURNAL OF INTERNATIONAL FINANCIAL MANAGEMENT & ACCOUNTING, Issue 2 2005Tony Kang The purpose of this study is to investigate why the information content of US earnings announcements of non-US firms cross-listing in the US varies with the degree of capital market segmentation in the cross-listing firms' countries of domicile. My evidence shows that indirect barriers to investing (i.e., accounting rules and liquidity differences) rather than direct investment barriers (i.e., investment restrictions) mainly account for this difference. After controlling for the level of accounting disclosure in a firm's country of domicile, I do not observe a systematic difference in the size of market's reaction to earnings announcements depending on the degree of market segmentation in the firm's country of domicile. This study contributes to the literature by providing evidence that accounting disclosure plays an important role in the integration of global capital markets. [source] Segmentation of human skull in MRI using statistical shape information from CT dataJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2009Defeng Wang PhD Abstract Purpose To automatically segment the skull from the MRI data using a model-based three-dimensional segmentation scheme. Materials and Methods This study exploited the statistical anatomy extracted from the CT data of a group of subjects by means of constructing an active shape model of the skull surfaces. To construct a reliable shape model, a novel approach was proposed to optimize the automatic landmarking on the coupled surfaces (i.e., the skull vault) by minimizing the description length that incorporated local thickness information. This model was then used to locate the skull shape in MRI of a different group of patients. Results Compared with performing landmarking separately on the coupled surfaces, the proposed landmarking method constructed models that had better generalization ability and specificity. The segmentation accuracies were measured by the Dice coefficient and the set difference, and compared with the method based on mathematical morphology operations. Conclusion The proposed approach using the active shape model based on the statistical skull anatomy presented in the head CT data contributes to more reliable segmentation of the skull from MRI data. J. Magn. Reson. Imaging 2009;30:490,498. © 2009 Wiley-Liss, Inc. [source] Segmentation of 3D microtomographic images of granular materials with the stochastic watershedJOURNAL OF MICROSCOPY, Issue 1 2010M. FAESSEL Summary Segmentation of 3D images of granular materials obtained by microtomography is not an easy task. Because of the conditions of acquisition and the nature of the media, the available images are not exploitable without a reliable method of extraction of the grains. The high connectivity in the medium, the disparity of the object's shape and the presence of image imperfections make classical segmentation methods (using image gradient and watershed constrained by markers) extremely difficult to perform efficiently. In this paper, we propose a non-parametric method using the stochastic watershed, allowing to estimate a 3D probability map of contours. Procedures allowing to extract final segmentation from this function are then presented. [source] Measurement of Whole-Brain Atrophy in Multiple SclerosisJOURNAL OF NEUROIMAGING, Issue 2004Daniel Pelletier MD ABSTRACT Brain atrophy reflects the net result of irreversible and destructive pathological processes in multiple sclerosis (MS). The gross morphological changes can be accurately quantified using standard magnetic resonance imaging (MRI) acquisitions and various image analysis tools. The current methods used to assess whole-brain atrophy in patients with MS can be classified into 2 groups based on their reliance on segmentation and registration. Segmentation-based methods employed to measure whole-brain atrophy in MS include the brain parenchymal fraction, the index of brain atrophy, the whole-brain ratio, the brain to intracranial capacity ratio, fuzzy connectedness/Udupa's method, 3DVIEWNIX, the Alfano method, and SIENAX. Current registration-based methods used to measure whole-brain atrophy in MS include the brain boundary shift integral, SIENA, statistical parametric mapping, template-driven seg mentation, and voxel-based morphometry. Most of the methods presented here are sensitive to subtle changes in brain structures and have been successfully applied to MS as measures of whole-brain atrophy. Yet comparative studies of these methods are limited and are complicated by the lack of a gold standard for image acquisition, a segmentation algorithm, an image analysis method, or a reproducibility measure. Overall, the measure of whole-brain atrophy from MRI contributes to an appreciation of the dynamics of MS pathology and its relationship to the clinical course of MS. Determination of the relative reproducibility, precision, sensitivity, and validity of these methods will promote the use of whole-brain atrophy measures as components of comprehensive MRI-based outcome assessment in MS clinical trials. [source] Characterizing and Reaching High-Risk Drinkers Using Audience SegmentationALCOHOLISM, Issue 8 2009Howard B. Moss Background:, Market or audience segmentation is widely used in social marketing efforts to help planners identify segments of a population to target for tailored program interventions. Market-based segments are typically defined by behaviors, attitudes, knowledge, opinions, or lifestyles. They are more helpful to health communication and marketing planning than epidemiologically defined groups because market-based segments are similar in respect to how they behave or might react to marketing and communication efforts. However, market segmentation has rarely been used in alcohol research. As an illustration of its utility, we employed commercial data that describes the sociodemographic characteristics of high-risk drinkers as an audience segment, including where they tend to live, lifestyles, interests, consumer behaviors, alcohol consumption behaviors, other health-related behaviors, and cultural values. Such information can be extremely valuable in targeting and planning public health campaigns, targeted mailings, prevention interventions, and research efforts. Methods:, We described the results of a segmentation analysis of those individuals who self-reported to consume 5 or more drinks per drinking episode at least twice in the last 30 days. The study used the proprietary PRIZMÔ (Claritas, Inc., San Diego, CA) audience segmentation database merged with the Center for Disease Control and Prevention's (CDC) Behavioral Risk Factor Surveillance System (BRFSS) database. The top 10 of the 66 PRIZMÔ audience segments for this risky drinking pattern are described. For five of these segments we provided additional in-depth details about consumer behavior and the estimates of the market areas where these risky drinkers resided. Results:, The top 10 audience segments (PRIZM clusters) most likely to engage in high-risk drinking are described. The cluster with the highest concentration of binge-drinking behavior is referred to as the "Cyber Millenials." This cluster is characterized as "the nation's tech-savvy singles and couples living in fashionable neighborhoods on the urban fringe." Almost 65% of Cyber Millenials households are found in the Pacific and Middle Atlantic regions of the United States. Additional consumer behaviors of the Cyber Millenials and other segments are also described. Conclusions:, Audience segmentation can assist in identifying and describing target audience segments, as well as identifying places where segments congregate on- or offline. This information can be helpful for recruiting subjects for alcohol prevention research as well as planning health promotion campaigns. Through commercial data about high-risk drinkers as "consumers," planners can develop interventions that have heightened salience in terms of opportunities, perceptions, and motivations, and have better media channel identification. [source] Inequality, Growth, and the Dynamics of Social SegmentationJOURNAL OF PUBLIC ECONOMIC THEORY, Issue 4 2009HUBERT KEMPF In this paper, we investigate the link between the dynamics of society segmentation into communities and the growth process, based on a simple human capital growth model. Using coalition theory, we study the socioeconomic dynamics of an economy over time, characterize it and prove that the economy converges to a steady state partition that may be segmented. Eventually the whole economy tends to a balanced growth path, exhibiting persistent inequality in the case of segmentation. We then provide sufficient conditions on initial inequality and the technology parameters generating local and global externalities for obtaining a segmented society in the long run. On the whole, the relationship between inequality and growth cannot be assessed without taking into consideration the stratification phenomena at work in society over time. [source] WHAT FEATURES DRIVE RATED BURGER CRAVEABILITY AT THE CONCEPT LEVEL?JOURNAL OF SENSORY STUDIES, Issue 1 2004JACQUELINE BECKLEY ABSTRACT This paper deals with the analysis of drivers for self-defined craveability assessed in an Internet-based, conjoint analysis task. The stimuli comprised 36 descriptions of restaurant hamburgers, including product features, benefits, restaurant names, and emotional reactions that might ensue after eating the hamburger. Elements were combined into concepts by experimental design, and the resulting concepts evaluated by 145 respondents, on the attribute of craveability. Models relating the presence/absence of concept elements to ratings revealed that statements about the hamburger itself were the most powerful, but that no single element was highest across all the respondents. Segmentation of the 145 individuals by the pattern of their individual utilities revealed four key segments. These are Elaborates who may be sensory-oriented and respond strongly to product descriptions; Classics who like the notion of a grilled hamburger; Imaginers who respond to restaurant name and advertising copy; and Emotionals who respond to statements about food to descriptions how the eater feels after consumption. [source] Semiautomatic segmentation and stenosis quantification of 3D contrast-enhanced MR angiograms of the internal carotid arteryMAGNETIC RESONANCE IN MEDICINE, Issue 4 2004Cornelis M. van Bemmel Abstract A technique is presented for the segmentation and quantification of stenosed internal carotid arteries (ICAs) in 3D contrast-enhanced MR angiography (CE-MRA). Segmentation with sub-pixel accuracy of the ICA is achieved via level-set techniques in which the central axis serves as the initialization. The central axis is determined between two user-defined points, and minimal user interaction is required. For quantification, the cross-sectional area is measured in the stenosis and at a reference segment in planes perpendicular to the central axis. The technique was applied to 20 ICAs. The variation in measurements obtained by this method in comparison with manual observations was 8.7%, which is smaller than the interobserver variability among three experts (11.0%). Magn Reson Med 51:753,760, 2004. © 2004 Wiley-Liss, Inc. [source] Automatic segmentation of the brain and intracranial cerebrospinal fluid in T1 -weighted volume MRI scans of the head, and its application to serial cerebral and intracranial volumetryMAGNETIC RESONANCE IN MEDICINE, Issue 5 2003Louis Lemieux A new fully automatic algorithm for the segmentation of the brain and total intracranial cerebrospinal fluid (CSF) from T1 -weighted volume MRI scans of the head, called Exbrain v.2, is described. The algorithm was developed in the context of serial intracranial volumetry. A brain mask obtained using a previous version of the algorithm forms the basis of the CSF segmentation. Improved brain segmentation is then obtained by iterative tracking of the brain,CSF interface. Gray matter (GM), white matter (WM), and intracranial CSF volumes and probability maps are calculated based on a model of intensity probability distribution (IPD) that includes two partial volume classes: GM-CSF and GM-WM. Accuracy was assessed using the Montreal Neurological Institute's (MNI) digital phantom scan. Reproducibility was assessed using scan pairs from 24 controls and 10 patients with epilepsy. Segmentation overlap with the gold standard was 98% for the brain and 95%, 96%, and 97% for the GM, WM, and total intracranial contents, respectively; CSF overlap was 86%. In the controls, the Bland and Altman coefficient of reliability (CR) was 35.2 cm3 for the total brain volume (TBV) and 29.0 cm3 for the intracranial volume (ICV). Scan-matching reduced CR to 25.2 cm3 and 17.1 cm3 for the TBV and ICV, respectively. For the patients, similar CR values were obtained for the ICV. Magn Reson Med 49:872,884, 2003. © 2003 Wiley-Liss, Inc. [source] Segmentation induced by intraluminal fatty acid in isolated guinea-pig duodenum and jejunumTHE JOURNAL OF PHYSIOLOGY, Issue 2 2004Rachel M. Gwynne Small intestinal movements depend on the composition of the chyme with mixing predominating at high nutrient levels and propulsion being prevalent at low nutrient levels. The mechanisms coupling nutrients to motility are unknown. We used computer analysis of video recordings of isolated guinea-pig duodenum, jejunum and ileum to examine movements induced by a fatty acid, decanoic acid. Increasing intraluminal pressure past a threshold using control saline consistently evoked propulsive reflexes: lumen-occluding constrictions appeared at the oral end propagating at 20.4 ± 2.4 mm s,1 (mean ±s.d., jejunum) to the anal end before being repeated until the intraluminal pressure was returned to control. Subthreshold pressure increases sometimes evoked a transient series of constrictions appearing at the oral end and propagating anally at 18.4 ± 4.7 mm s,1 (jejunum). At basal pressures, decanoic acid dose-dependently induced motor activity consisting of 40,60 s episodes of constrictions separated by 40,200 s periods of quiescence and lasting up to 2 h. Five contraction patterns were identified within episodes including localized stationary constrictions; constrictions that propagated slowly (5,8 mm s,1) for short distances orally or anally; and constrictions that propagated orally or anally for the length of the preparation at 14,20 mm s,1. Decanoic acid induced motor activity was reversibly abolished by tetrodotoxin (3 ,m), hyoscine (1 ,m) and hexamethonium (100 ,m), but was insensitive to blockade of P2 purinoceptors by PPADS (60 ,m). Thus, decanoic acid induces motor activity equivalent to segmentation in guinea-pig small intestine in vitro and this depends on intrinsic neural pathways. [source] Using Population Segmentation to Provide Better Health Care for All: The "Bridges to Health" ModelTHE MILBANK QUARTERLY, Issue 2 2007JOANNE LYNN The model discussed in this article divides the population into eight groups: people in good health, in maternal/infant situations, with an acute illness, with stable chronic conditions, with a serious but stable disability, with failing health near death, with advanced organ system failure, and with long-term frailty. Each group has its own definitions of optimal health and its own priorities among services. Interpreting these population-focused priorities in the context of the Institute of Medicine's six goals for quality yields a framework that could shape planning for resources, care arrangements, and service delivery, thus ensuring that each person's health needs can be met effectively and efficiently. Since this framework would guide each population segment across the institute's "Quality Chasm," it is called the "Bridges to Health" model. [source] The Expansion, Diversification, and Segmentation of Power in Late Prehispanic NascaARCHEOLOGICAL PAPERS OF THE AMERICAN ANTHROPOLOGICAL ASSOCIATION, Issue 1 2004Christina A. Conlee During the Late Intermediate Period (A.D. 1000,1476) the organization and foundation of power in Nasca was transformed from earlier times. Previously, religious resources were central to the development and maintenance of the political and social hierarchy. After the collapse of the Wari Empire and a period of balkanization, the resources used to establish and maintain power broadened considerably. The expansion of the power base into new realms coincided with an increase in the number of local elites in the drainage. There was no longer a focus on regional ceremonial centers; instead, elites were able to build power through a variety of activities including exchange, craft production (with a focus on utilitarian items), feasting, community-based ritual activities, and probably warfare and defense. During this period the levels of the political hierarchy grew and a more heterarchical type of regional polity developed. [source] Segmentation and Estimation for SNP Microarrays: A Bayesian Multiple Change-Point ApproachBIOMETRICS, Issue 3 2010Yu Chuan Tai Summary High-density single-nucleotide polymorphism (SNP) microarrays provide a useful tool for the detection of copy number variants (CNVs). The analysis of such large amounts of data is complicated, especially with regard to determining where copy numbers change and their corresponding values. In this article, we propose a Bayesian multiple change-point model (BMCP) for segmentation and estimation of SNP microarray data. Segmentation concerns separating a chromosome into regions of equal copy number differences between the sample of interest and some reference, and involves the detection of locations of copy number difference changes. Estimation concerns determining true copy number for each segment. Our approach not only gives posterior estimates for the parameters of interest, namely locations for copy number difference changes and true copy number estimates, but also useful confidence measures. In addition, our algorithm can segment multiple samples simultaneously, and infer both common and rare CNVs across individuals. Finally, for studies of CNVs in tumors, we incorporate an adjustment factor for signal attenuation due to tumor heterogeneity or normal contamination that can improve copy number estimates. [source] Discussion of "A Bayesian Approach to DNA Sequence Segmentation"BIOMETRICS, Issue 2 2005Hilary S. Booth This article discusses the results in Boys and Henderson (2004, Biometrics60, 573,581) in which the authors propose a new approach to the classification of genomic DNA into a number of hidden Markov states with a variable order of dependency, potentially allowing for the high-throughput detection of structure within genomic DNA. This article is likely to be an important point of departure for further modeling of this type. We question whether the genome of the bacteriophage lambda is the most appropriate example with which to demonstrate the method's effectiveness, whether it can be expected that the method will carry over to genomes where there is only one direction of transcription and no operon structure, and suggest a graphical display that seems to offer insight into the results. It would be interesting to see an analysis that uses the codon alphabet. [source] Discussions on "A Bayesian Approach to DNA Sequence Segmentation"BIOMETRICS, Issue 3 2004Mayetri Gupta No abstract is available for this article. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||