The lack of selection bias in a snowball sampled case-control study on drug abuse.
Lopes, C S; Rodrigues, L C; Sichieri, R
1996-12-01
Friend controls in matched case-control studies can be a potential source of bias based on the assumption that friends are more likely to share exposure factors. This study evaluates the role of selection bias in a case-control study that used the snowball sampling method based on friendship for the selection of cases and controls. The cases selected fro the study were drug abusers located in the community. Exposure was defined by the presence of at least one psychiatric diagnosis. Psychiatric and drug abuse/dependence diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. Cases and controls were matched on sex, age and friendship. The measurement of selection bias was made through the comparison of the proportion of exposed controls selected by exposed cases (p1) with the proportion of exposed controls selected by unexposed cases (p2). If p1 = p2 then, selection bias should not occur. The observed distribution of the 185 matched pairs having at least one psychiatric disorder showed a p1 value of 0.52 and a p2 value of 0.51, indicating no selection bias in this study. Our findings support the idea that the use of friend controls can produce a valid basis for a case-control study.
Finding The Limit: The Strategic Potential Of The Network Based Actor
2016-12-01
6 E. CASE STUDY SELECTION AND PROCESS .......................................6 1. Selection of Baseline Case Studies: Pierre-Charles...Pathé and the Trust ..................................................................................7 2. Selection of Test Case Studies...academic debate, which argues that non-state, network-based actors can have a strategic planning capacity. E. CASE STUDY SELECTION AND PROCESS This
2016-09-01
PUBLIC SECTOR RESEARCH & DEVELOPMENT PORTFOLIO SELECTION PROCESS: A CASE STUDY OF QUANTITATIVE SELECTION AND OPTIMIZATION by Jason A. Schwartz...PUBLIC SECTOR RESEARCH & DEVELOPMENT PORTFOLIO SELECTION PROCESS: A CASE STUDY OF QUANTITATIVE SELECTION AND OPTIMIZATION 5. FUNDING NUMBERS 6...describing how public sector organizations can implement a research and development (R&D) portfolio optimization strategy to maximize the cost
Selecting Cases for Intensive Analysis: A Diversity of Goals and Methods
ERIC Educational Resources Information Center
Gerring, John; Cojocaru, Lee
2016-01-01
This study revisits the task of case selection in case study research, proposing a new typology of strategies that is explicit, disaggregated, and relatively comprehensive. A secondary goal is to explore the prospects for case selection by "algorithm," aka "ex ante," "automatic," "quantitative,"…
Finch, Caroline F; Ullah, Shahid; McIntosh, Andrew S
2011-01-01
Several important methodological issues need to be considered when designing sports injury case-control studies. Major design goals for case-control studies include the accounting for prior injury risk exposure, and optimal definitions of both cases and suitable controls are needed to ensure this. This article reviews methodological aspects of published sports injury case-control studies, particularly with regard to the selection of controls. It argues for a new approach towards selecting controls for case-control studies that draws on an interface between epidemiological and biomechanical concepts. A review was conducted to identify sport injury case-control studies published in the peer-review literature during 1985-2008. Overall, 32 articles were identified, of which the majority related to upper or lower extremity injuries. Matching considerations were used for control selection in 16 studies. Specific mention of application of biomechanical principles in the selection of appropriate controls was absent from all studies, including those purporting to evaluate the benefits of personal protective equipment to protect against impact injury. This is a problem because it could lead to biased conclusions, as cases and controls are not fully comparable in terms of similar biomechanical impact profiles relating to the injury incident, such as site of the impact on the body. The strength of the conclusions drawn from case-control studies, and the extent to which results can be generalized, is directly influenced by the definition and recruitment of cases and appropriate controls. Future studies should consider the interface between epidemiological and biomechanical concepts when choosing appropriate controls to ensure that proper adjustment of prior exposure to injury risk is made. To provide necessary guidance for the optimal selection of controls in case-control studies of interventions to prevent sports-related impact injury, this review outlines a new case-control selection strategy that reflects the importance of biomechanical considerations, which ensures that controls are selected based on the presence of the same global injury mechanism as the cases. To summarize, the general biomechanical principles that should apply to the selection of controls in future case-control studies are as follows: (i) each control must have been exposed to the same global injury mechanism as the case, (e.g. head impact, fall onto outstretched arm); and (ii) intrinsic (individual) factors (e.g. age, sex, skill level) that might modify the person's response to the relevant biomechanical loads are adjusted when either selecting the controls or are in the analysis phase. The same considerations for control selection apply to other study designs such as matched cohort studies or case-crossover studies.
A Careful Look at Modern Case Selection Methods
ERIC Educational Resources Information Center
Herron, Michael C.; Quinn, Kevin M.
2016-01-01
Case studies appear prominently in political science, sociology, and other social science fields. A scholar employing a case study research design in an effort to estimate causal effects must confront the question, how should cases be selected for analysis? This question is important because the results derived from a case study research program…
Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E
2001-01-01
Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.
Methodology Series Module 2: Case-control Studies.
Setia, Maninder Singh
2016-01-01
Case-Control study design is a type of observational study. In this design, participants are selected for the study based on their outcome status. Thus, some participants have the outcome of interest (referred to as cases), whereas others do not have the outcome of interest (referred to as controls). The investigator then assesses the exposure in both these groups. The investigator should define the cases as specifically as possible. Sometimes, definition of a disease may be based on multiple criteria; thus, all these points should be explicitly stated in case definition. An important aspect of selecting a control is that they should be from the same 'study base' as that of the cases. We can select controls from a variety of groups. Some of them are: General population; relatives or friends; and hospital patients. Matching is often used in case-control control studies to ensure that the cases and controls are similar in certain characteristics, and it is a useful technique to increase the efficiency of the study. Case-Control studies can usually be conducted relatively faster and are inexpensive - particularly when compared with cohort studies (prospective). It is useful to study rare outcomes and outcomes with long latent periods. This design is not very useful to study rare exposures. Furthermore, they may also be prone to certain biases - selection bias and recall bias.
Malof, Jordan M.; Mazurowski, Maciej A.; Tourassi, Georgia D.
2013-01-01
Case selection is a useful approach for increasing the efficiency and performance of case-based classifiers. Multiple techniques have been designed to perform case selection. This paper empirically investigates how class imbalance in the available set of training cases can impact the performance of the resulting classifier as well as properties of the selected set. In this study, the experiments are performed using a dataset for the problem of detecting breast masses in screening mammograms. The classification problem was binary and we used a k-nearest neighbor classifier. The classifier’s performance was evaluated using the Receiver Operating Characteristic (ROC) area under the curve (AUC) measure. The experimental results indicate that although class imbalance reduces the performance of the derived classifier and the effectiveness of selection at improving overall classifier performance, case selection can still be beneficial, regardless of the level of class imbalance. PMID:21820273
ERIC Educational Resources Information Center
Klein, Hans E., Ed.
This book presents a selection of papers from the international, interdisciplinary conference of the World Association for Case Method Research & Application. Papers are categorized into seven areas: (1) "International Case Studies" (e.g., event-based entrepreneurship, case studies on consumer complaints, and strategic quality…
A Mixed Methods Sampling Methodology for a Multisite Case Study
ERIC Educational Resources Information Center
Sharp, Julia L.; Mobley, Catherine; Hammond, Cathy; Withington, Cairen; Drew, Sam; Stringfield, Sam; Stipanovic, Natalie
2012-01-01
The flexibility of mixed methods research strategies makes such approaches especially suitable for multisite case studies. Yet the utilization of mixed methods to select sites for these studies is rarely reported. The authors describe their pragmatic mixed methods approach to select a sample for their multisite mixed methods case study of a…
Methodology Series Module 2: Case-control Studies
Setia, Maninder Singh
2016-01-01
Case-Control study design is a type of observational study. In this design, participants are selected for the study based on their outcome status. Thus, some participants have the outcome of interest (referred to as cases), whereas others do not have the outcome of interest (referred to as controls). The investigator then assesses the exposure in both these groups. The investigator should define the cases as specifically as possible. Sometimes, definition of a disease may be based on multiple criteria; thus, all these points should be explicitly stated in case definition. An important aspect of selecting a control is that they should be from the same ‘study base’ as that of the cases. We can select controls from a variety of groups. Some of them are: General population; relatives or friends; and hospital patients. Matching is often used in case-control control studies to ensure that the cases and controls are similar in certain characteristics, and it is a useful technique to increase the efficiency of the study. Case-Control studies can usually be conducted relatively faster and are inexpensive – particularly when compared with cohort studies (prospective). It is useful to study rare outcomes and outcomes with long latent periods. This design is not very useful to study rare exposures. Furthermore, they may also be prone to certain biases – selection bias and recall bias. PMID:27057012
A History and Case Study at a Selected Tribal College
ERIC Educational Resources Information Center
Oltrogge, Micheal P.
2010-01-01
"A History and Case Study at a Selected Tribal College" focuses on a tribally chartered two-year institution of higher education. The selected Tribal College serves Native American and non-Native American populations on two separate and distinct reservations and one urban location. This study surveys the history to answer basic foundational and…
Walsh, Matthew C; Trentham-Dietz, Amy; Gangnon, Ronald E; Nieto, F Javier; Newcomb, Polly A; Palta, Mari
2012-06-01
Increasing numbers of individuals are choosing to opt out of population-based sampling frames due to privacy concerns. This is especially a problem in the selection of controls for case-control studies, as the cases often arise from relatively complete population-based registries, whereas control selection requires a sampling frame. If opt out is also related to risk factors, bias can arise. We linked breast cancer cases who reported having a valid driver's license from the 2004-2008 Wisconsin women's health study (N = 2,988) with a master list of licensed drivers from the Wisconsin Department of Transportation (WDOT). This master list excludes Wisconsin drivers that requested their information not be sold by the state. Multivariate-adjusted selection probability ratios (SPR) were calculated to estimate potential bias when using this driver's license sampling frame to select controls. A total of 962 cases (32%) had opted out of the WDOT sampling frame. Cases age <40 (SPR = 0.90), income either unreported (SPR = 0.89) or greater than $50,000 (SPR = 0.94), lower parity (SPR = 0.96 per one-child decrease), and hormone use (SPR = 0.93) were significantly less likely to be covered by the WDOT sampling frame (α = 0.05 level). Our results indicate the potential for selection bias due to differential opt out between various demographic and behavioral subgroups of controls. As selection bias may differ by exposure and study base, the assessment of potential bias needs to be ongoing. SPRs can be used to predict the direction of bias when cases and controls stem from different sampling frames in population-based case-control studies.
ERIC Educational Resources Information Center
Klein, Hans E., Ed.
This book presents a selection of papers from the annual, international, interdisciplinary conference of the World Association for Case Method Research & Application. Papers are categorized into six areas: (1) "Case Studies and Research" (e.g., subjectivity as a source of insight in case study research, evolution of a teaching case,…
Collaborative Textbook Selection: A Case Study Leading to Practical and Theoretical Considerations
ERIC Educational Resources Information Center
Czerwionka, Lori; Gorokhovsky, Bridget
2015-01-01
This case study developed a collaborative approach to the selection of a Spanish language textbook. The collaborative process consisted of six steps, detailed in this article: team building, generating evaluation criteria, formulating a meaningful rubric, selecting prospective textbooks, calculating rubric results, and reflectively reviewing…
Hammitt, Laura L.; Deloria Knoll, Maria; Baggett, Henry C.; Brooks, W. Abdullah; Howie, Stephen R. C.; Kotloff, Karen L.; Levine, Orin S.; Madhi, Shabir A.; Murdoch, David R.; Scott, J. Anthony G.; Thea, Donald M.; Driscoll, Amanda J.; Karron, Ruth A.; Park, Daniel E.; Prosperi, Christine; Zeger, Scott L.; O’Brien, Katherine L.; Feikin, Daniel R.; O’Brien, Katherine L.; Levine, Orin S.; Knoll, Maria Deloria; Feikin, Daniel R.; DeLuca, Andrea N.; Driscoll, Amanda J.; Fu, Wei; Hammitt, Laura L.; Higdon, Melissa M.; Kagucia, E. Wangeci; Karron, Ruth A.; Li, Mengying; Park, Daniel E.; Prosperi, Christine; Wu, Zhenke; Zeger, Scott L.; Watson, Nora L.; Crawley, Jane; Murdoch, David R.; Brooks, W. Abdullah; Endtz, Hubert P.; Zaman, Khalequ; Goswami, Doli; Hossain, Lokman; Jahan, Yasmin; Ashraf, Hasan; Howie, Stephen R. C.; Ebruke, Bernard E.; Antonio, Martin; McLellan, Jessica; Machuka, Eunice; Shamsul, Arifin; Zaman, Syed M.A.; Mackenzie, Grant; Scott, J. Anthony G.; Awori, Juliet O.; Morpeth, Susan C.; Kamau, Alice; Kazungu, Sidi; Kotloff, Karen L.; Tapia, Milagritos D.; Sow, Samba O.; Sylla, Mamadou; Tamboura, Boubou; Onwuchekwa, Uma; Kourouma, Nana; Toure, Aliou; Madhi, Shabir A.; Moore, David P.; Adrian, Peter V.; Baillie, Vicky L.; Kuwanda, Locadiah; Mudau, Azwifarwi; Groome, Michelle J.; Baggett, Henry C.; Thamthitiwat, Somsak; Maloney, Susan A.; Bunthi, Charatdao; Rhodes, Julia; Sawatwong, Pongpun; Akarasewi, Pasakorn; Thea, Donald M.; Mwananyanda, Lawrence; Chipeta, James; Seidenberg, Phil; Mwansa, James; wa Somwe, Somwe; Kwenda, Geoffrey
2017-01-01
Abstract Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. PMID:28575354
ERIC Educational Resources Information Center
Nashman-Smith, Mona
2017-01-01
Selective mutism (SM) is considered a communication and anxiety disorder that afflicts about 1% of students. The rarity of SM and the isolated cases of this condition has rendered the elementary to secondary school experience for a student with SM difficult to study. Utilizing a qualitative approach, this phenomenological case study examined the…
Higdon, Melissa M; Hammitt, Laura L; Deloria Knoll, Maria; Baggett, Henry C; Brooks, W Abdullah; Howie, Stephen R C; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; Murdoch, David R; Scott, J Anthony G; Thea, Donald M; Driscoll, Amanda J; Karron, Ruth A; Park, Daniel E; Prosperi, Christine; Zeger, Scott L; O'Brien, Katherine L; Feikin, Daniel R
2017-06-15
Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.
Methodology or method? A critical review of qualitative case study reports.
Hyett, Nerida; Kenny, Amanda; Dickson-Swift, Virginia
2014-01-01
Despite on-going debate about credibility, and reported limitations in comparison to other approaches, case study is an increasingly popular approach among qualitative researchers. We critically analysed the methodological descriptions of published case studies. Three high-impact qualitative methods journals were searched to locate case studies published in the past 5 years; 34 were selected for analysis. Articles were categorized as health and health services (n=12), social sciences and anthropology (n=7), or methods (n=15) case studies. The articles were reviewed using an adapted version of established criteria to determine whether adequate methodological justification was present, and if study aims, methods, and reported findings were consistent with a qualitative case study approach. Findings were grouped into five themes outlining key methodological issues: case study methodology or method, case of something particular and case selection, contextually bound case study, researcher and case interactions and triangulation, and study design inconsistent with methodology reported. Improved reporting of case studies by qualitative researchers will advance the methodology for the benefit of researchers and practitioners.
Spatio-temporal Bayesian model selection for disease mapping
Carroll, R; Lawson, AB; Faes, C; Kirby, RS; Aregay, M; Watjou, K
2016-01-01
Spatio-temporal analysis of small area health data often involves choosing a fixed set of predictors prior to the final model fit. In this paper, we propose a spatio-temporal approach of Bayesian model selection to implement model selection for certain areas of the study region as well as certain years in the study time line. Here, we examine the usefulness of this approach by way of a large-scale simulation study accompanied by a case study. Our results suggest that a special case of the model selection methods, a mixture model allowing a weight parameter to indicate if the appropriate linear predictor is spatial, spatio-temporal, or a mixture of the two, offers the best option to fitting these spatio-temporal models. In addition, the case study illustrates the effectiveness of this mixture model within the model selection setting by easily accommodating lifestyle, socio-economic, and physical environmental variables to select a predominantly spatio-temporal linear predictor. PMID:28070156
Treating Selective Mutism Using Modular CBT for Child Anxiety: A Case Study
ERIC Educational Resources Information Center
Reuther, Erin T.; Davis, Thompson E., III; Moree, Brittany N.; Matson, Johnny L.
2011-01-01
Selective mutism is a rare, debilitating condition usually seen in children. Unfortunately, there is little research examining effective treatments for this disorder, and designing an evidence-based treatment plan can be difficult. This case study presents the evidence-based treatment of an 8-year-old Caucasian boy with selective mutism using an…
Ni, Ai; Cai, Jianwen
2018-07-01
Case-cohort designs are commonly used in large epidemiological studies to reduce the cost associated with covariate measurement. In many such studies the number of covariates is very large. An efficient variable selection method is needed for case-cohort studies where the covariates are only observed in a subset of the sample. Current literature on this topic has been focused on the proportional hazards model. However, in many studies the additive hazards model is preferred over the proportional hazards model either because the proportional hazards assumption is violated or the additive hazards model provides more relevent information to the research question. Motivated by one such study, the Atherosclerosis Risk in Communities (ARIC) study, we investigate the properties of a regularized variable selection procedure in stratified case-cohort design under an additive hazards model with a diverging number of parameters. We establish the consistency and asymptotic normality of the penalized estimator and prove its oracle property. Simulation studies are conducted to assess the finite sample performance of the proposed method with a modified cross-validation tuning parameter selection methods. We apply the variable selection procedure to the ARIC study to demonstrate its practical use.
ERIC Educational Resources Information Center
Martin, Michaela, Ed.
Five case studies were conducted to collect empirical evidence on innovative mechanisms through which universities worldwide manage their relations with industry. Cases were selected from institutions of higher education in Israel, Papua New Guinea, Turkey, Brazil, and Uganda. These studies were selected for their innovative approaches, but also…
Vrijheid, Martine; Richardson, Lesley; Armstrong, Bruce K; Auvinen, Anssi; Berg, Gabriele; Carroll, Matthew; Chetrit, Angela; Deltour, Isabelle; Feychting, Maria; Giles, Graham G; Hours, Martine; Iavarone, Ivano; Lagorio, Susanna; Lönn, Stefan; McBride, Mary; Parent, Marie-Elise; Sadetzki, Siegal; Salminen, Tina; Sanchez, Marie; Schlehofer, Birgitte; Schüz, Joachim; Siemiatycki, Jack; Tynes, Tore; Woodward, Alistair; Yamaguchi, Naohito; Cardis, Elisabeth
2009-01-01
To quantitatively assess the impact of selection bias caused by nonparticipation in a multinational case-control study of mobile phone use and brain tumor. Non-response questionnaires (NRQ) were completed by a sub-set of nonparticipants. Selection bias factors were calculated based on the prevalence of mobile phone use reported by nonparticipants with NRQ data, and on scenarios of hypothetical exposure prevalence for other nonparticipants. Regular mobile phone use was reported less frequently by controls and cases who completed the NRQ (controls, 56%; cases, 50%) than by those who completed the full interview (controls, 69%; cases, 66%). This relationship was consistent across study centers, sex, and age groups. Lower education and more recent start of mobile phone use were associated with refusal to participate. Bias factors varied between 0.87 and 0.92 in the most plausible scenarios. Refusal to participate in brain tumor case-control studies seems to be related to less prevalent use of mobile phones, and this could result in a downward bias of around 10% in odds ratios for regular mobile phone use. The use of simple selection bias estimation methods in case-control studies can give important insights into the extent of any bias, even when nonparticipant information is incomplete.
Bourdellon, Loic; Thilly, Nathalie; Fougnot, Sébastien; Pulcini, Céline; Henard, Sandrine
2017-08-01
Selective reporting of antibiotic susceptibility test (AST) results is a potential intervention for laboratory-based antibiotic stewardship. The aim of this study was to assess the impact of AST reporting on the appropriateness of antibiotics selected by French general practitioners for urinary tract infections (UTIs). A randomised controlled case-vignette study in a region of northeast France surveyed general practitioners between July and October 2015 on treatment of four clinical cases of community-acquired Escherichia coli UTIs (two cases of complicated cystitis, one of acute pyelonephritis and one male UTI). In Group A, selective reporting of AST results was used for the first two cases and complete reporting for the other two cases; these were reversed in Group B. The overall participation rate was 131/198 (66.2%). Provision of selective AST results significantly increased the rate of adherence to national guidelines for first-line antibiotic treatment in Cases 1, 3 and 4 by 22.4% (55.2% vs. 32.8%, P = 0.01), 67.5% (75.0% vs. 7.5%, P <0.001) and 36.3% (45.3% vs. 9.0%, P <0.001), respectively. The improvement in compliance was not significant for Case 2. Prescriptions of amoxicillin-clavulanic acid, fluoroquinolones and cephalosporins decreased by 25.0% to 45.0%, depending on the clinical vignette. Most (106/131, 81.0%) participants favoured the routine use of selective reporting of AST results. In conclusion, selective reporting of AST results seems to improve antibiotic prescribing practices in primary care, and may be considered a key element of antimicrobial stewardship programmes. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.
Aydin, Denis; Feychting, Maria; Schüz, Joachim; Andersen, Tina Veje; Poulsen, Aslak Harbo; Prochazka, Michaela; Klaeboe, Lars; Kuehni, Claudia E; Tynes, Tore; Röösli, Martin
2011-07-01
Whether the use of mobile phones is a risk factor for brain tumors in adolescents is currently being studied. Case--control studies investigating this possible relationship are prone to recall error and selection bias. We assessed the potential impact of random and systematic recall error and selection bias on odds ratios (ORs) by performing simulations based on real data from an ongoing case--control study of mobile phones and brain tumor risk in children and adolescents (CEFALO study). Simulations were conducted for two mobile phone exposure categories: regular and heavy use. Our choice of levels of recall error was guided by a validation study that compared objective network operator data with the self-reported amount of mobile phone use in CEFALO. In our validation study, cases overestimated their number of calls by 9% on average and controls by 34%. Cases also overestimated their duration of calls by 52% on average and controls by 163%. The participation rates in CEFALO were 83% for cases and 71% for controls. In a variety of scenarios, the combined impact of recall error and selection bias on the estimated ORs was complex. These simulations are useful for the interpretation of previous case-control studies on brain tumor and mobile phone use in adults as well as for the interpretation of future studies on adolescents. Copyright © 2011 Wiley-Liss, Inc.
DOT National Transportation Integrated Search
2011-03-31
This report synthesizes the findings from four case studies that assess how select organizations (the City of Boulder, Colorado's Transportation Division, the Center for Neighborhood Technology, the University of Oregon and the Oregon Transportation ...
Mensah, F K; Willett, E V; Simpson, J; Smith, A G; Roman, E
2007-09-15
Substantial heterogeneity has been observed among case-control studies investigating associations between non-Hodgkin's lymphoma and familial characteristics, such as birth order and sibship size. The potential role of selection bias in explaining such heterogeneity is considered within this study. Selection bias according to familial characteristics and socioeconomic status is investigated within a United Kingdom-based case-control study of non-Hodgkin's lymphoma diagnosed during 1998-2001. Reported distributions of birth order and maternal age are each compared with expected reference distributions derived using national birth statistics from the United Kingdom. A method is detailed in which yearly data are used to derive expected distributions, taking account of variability in birth statistics over time. Census data are used to reweight both the case and control study populations such that they are comparable with the general population with regard to socioeconomic status. The authors found little support for an association between non-Hodgkin's lymphoma and birth order or family size and little evidence for an influence of selection bias. However, the findings suggest that between-study heterogeneity could be explained by selection biases that influence the demographic characteristics of participants.
Distributed Leadership in Elementary Schools: An Exploratory Multiple Case Study
ERIC Educational Resources Information Center
Valdez, Vidal
2016-01-01
The purpose of this study was to explore distributed leadership and how leadership practices are actualized in three selected schools in Southern California. This qualitative, multiple case study used survey research and interviews to assess how distributed leadership was practiced in three selected elementary schools located within one school…
Methodology or method? A critical review of qualitative case study reports
Hyett, Nerida; Kenny, Amanda; Dickson-Swift, Virginia
2014-01-01
Despite on-going debate about credibility, and reported limitations in comparison to other approaches, case study is an increasingly popular approach among qualitative researchers. We critically analysed the methodological descriptions of published case studies. Three high-impact qualitative methods journals were searched to locate case studies published in the past 5 years; 34 were selected for analysis. Articles were categorized as health and health services (n=12), social sciences and anthropology (n=7), or methods (n=15) case studies. The articles were reviewed using an adapted version of established criteria to determine whether adequate methodological justification was present, and if study aims, methods, and reported findings were consistent with a qualitative case study approach. Findings were grouped into five themes outlining key methodological issues: case study methodology or method, case of something particular and case selection, contextually bound case study, researcher and case interactions and triangulation, and study design inconsistent with methodology reported. Improved reporting of case studies by qualitative researchers will advance the methodology for the benefit of researchers and practitioners. PMID:24809980
ERIC Educational Resources Information Center
Sakirudeen, Abisola Oladeni; Sanni, Kudirat Bimbo
2017-01-01
The study examined study habits and academic performance of secondary school students in Mathematics. A case study of selected secondary schools in Uyo Local Education Council. The main purpose of the study was to investigate the relationship between study habits and academic performance of secondary school students in Mathematics. To carry out…
Jagoda, Evelyn; Lawson, Daniel J; Wall, Jeffrey D; Lambert, David; Muller, Craig; Westaway, Michael; Leavesley, Matthew; Capellini, Terence D; Mirazón Lahr, Marta; Gerbault, Pascale; Thomas, Mark G; Migliano, Andrea Bamberg; Willerslev, Eske; Metspalu, Mait; Pagani, Luca
2018-01-01
Abstract Recent studies have reported evidence suggesting that portions of contemporary human genomes introgressed from archaic hominin populations went to high frequencies due to positive selection. However, no study to date has specifically addressed the postintrogression population dynamics of these putative cases of adaptive introgression. Here, for the first time, we specifically define cases of immediate adaptive introgression (iAI) in which archaic haplotypes rose to high frequencies in humans as a result of a selective sweep that occurred shortly after the introgression event. We define these cases as distinct from instances of selection on standing introgressed variation (SI), in which an introgressed haplotype initially segregated neutrally and subsequently underwent positive selection. Using a geographically diverse data set, we report novel cases of selection on introgressed variation in living humans and shortlist among these cases those whose selective sweeps are more consistent with having been the product of iAI rather than SI. Many of these novel inferred iAI haplotypes have potential biological relevance, including three that contain immune-related genes in West Siberians, South Asians, and West Eurasians. Overall, our results suggest that iAI may not represent the full picture of positive selection on archaically introgressed haplotypes in humans and that more work needs to be done to analyze the role of SI in the archaic introgression landscape of living humans. PMID:29220488
2016-10-01
workshop, and use case development for automated and autonomous systems for CSS. The scoping study covers key concepts and trends, a technology scan, and...requirements and delimiters for the selected technologies. The report goes on to present detailed use cases for two technologies of interest: semi...selected use cases . As a result of the workshop, the large list of technologies and applications from the scoping study was narrowed down to the top
Lahkola, Anna; Salminen, Tiina; Auvinen, Anssi
2005-05-01
To evaluate the possible selection bias related to the differential participation of mobile phone users and non-users in a Finnish case-control study on mobile phone use and brain tumors. Mobile phone use was investigated among 777 controls and 726 cases participating in the full personal interview (full participants), and 321 controls and 103 cases giving only a brief phone interview (incomplete participants). To assess selection bias, the Mantel-Haenszel estimate of odds ratio was calculated for three different groups: full study participants, incomplete participants, and a combined group consisting of both full and incomplete participants. Among controls, 83% of the full participants and 73% of the incomplete participants had regularly used a mobile phone. Among cases, the figures were 76% and 64%, respectively. The odds ratio for brain tumor based on the combined group of full and incomplete participants was slightly closer to unity than that based only on the full participants. Selection bias tends to distort the effect estimates below unity, while analyses based on more comprehensive material gave results close to unity.
ERIC Educational Resources Information Center
Dole, Janice; And Others
A study followed three textbook adoption committees as they evaluated basal reading programs. The committees used "A Guide to Selecting Basal Reading Programs" (developed at the Center for the Study of Reading) to help them evaluate the quality of instruction in existing programs. Case studies of the three committees sought to address the…
Lai, Shih-Wei; Liao, Kuan-Fu; Lin, Cheng-Li; Lin, Hsien-Feng
2017-01-01
Objectives: The purpose of the study was to assess the relationship between selective serotonin reuptake inhibitors use and hepatocellular carcinoma in Taiwan. Methods: Using the database of the Taiwan National Health Insurance Program, we conducted a case-control study to identify 4901 subjects aged 20 years and more with newly diagnosed hepatocellular carcinoma in 2000-2013 as the cases. We randomly selected 19604 subjects aged 20 years and more without hepatocellular carcinoma as the controls. Both cases and controls were matched with sex and age. Ever use of selective serotonin reuptake inhibitors was defined as a subject who had at least a prescription for selective serotonin reuptake inhibitors before index date. Never use was defined as a subject who never had a prescription for selective serotonin reuptake inhibitors before index date. The odds ratio (OR) and 95% confidence interval (CI) for hepatocellular carcinoma associated with selective serotonin reuptake inhibitors use was estimated by the multivariable logistic regression model. Results: Among subjects with any one of the comorbid conditions associated with hepatocellular carcinoma, the adjusted OR of hepatocellular carcinoma was 0.89 (95% CI 0.75, 1.06) for subjects with ever use of selective serotonin reuptake inhibitors, comparing with never use. Conclusion: The findings indicate that among subjects with any one of the comorbid conditions associated with hepatocellular carcinoma, no significant association can be detected between selective serotonin reuptake inhibitors use and hepatocellular carcinoma.
A traits-based approach for prioritizing species for monitoring and surrogacy selection
Pracheil, Brenda M.; McManamay, Ryan A.; Bevelhimer, Mark S.; ...
2016-11-28
The bar for justifying the use of vertebrate animals for study is being increasingly raised, thus requiring increased rigor for species selection and study design. Although we have power analyses to provide quantitative backing for the numbers of organisms used, quantitative backing for selection of study species is not frequently employed. This can be especially important when measuring the impacts of ecosystem alteration, when study species must be chosen that are both sensitive to the alteration and of sufficient abundance for study. Just as important is providing justification for designation of surrogate species for study, especially when the species ofmore » interest is rare or of conservation concern and selection of an appropriate surrogate can have legal implications. In this study, we use a combination of GIS, a fish traits database and multivariate statistical analyses to quantitatively prioritize species for study and to determine potential study surrogate species. We provide two case studies to illustrate our quantitative, traits-based approach for designating study species and surrogate species. In the first case study, we select broadly representative fish species to understand the effects of turbine passage on adult fishes based on traits that suggest sensitivity to turbine passage. In our second case study, we present a framework for selecting a surrogate species for an endangered species. Lastly, we suggest that our traits-based framework can provide quantitative backing and added justification to selection of study species while expanding the inference space of study results.« less
A traits-based approach for prioritizing species for monitoring and surrogacy selection
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pracheil, Brenda M.; McManamay, Ryan A.; Bevelhimer, Mark S.
The bar for justifying the use of vertebrate animals for study is being increasingly raised, thus requiring increased rigor for species selection and study design. Although we have power analyses to provide quantitative backing for the numbers of organisms used, quantitative backing for selection of study species is not frequently employed. This can be especially important when measuring the impacts of ecosystem alteration, when study species must be chosen that are both sensitive to the alteration and of sufficient abundance for study. Just as important is providing justification for designation of surrogate species for study, especially when the species ofmore » interest is rare or of conservation concern and selection of an appropriate surrogate can have legal implications. In this study, we use a combination of GIS, a fish traits database and multivariate statistical analyses to quantitatively prioritize species for study and to determine potential study surrogate species. We provide two case studies to illustrate our quantitative, traits-based approach for designating study species and surrogate species. In the first case study, we select broadly representative fish species to understand the effects of turbine passage on adult fishes based on traits that suggest sensitivity to turbine passage. In our second case study, we present a framework for selecting a surrogate species for an endangered species. Lastly, we suggest that our traits-based framework can provide quantitative backing and added justification to selection of study species while expanding the inference space of study results.« less
van Rein, Nienke; Cannegieter, Suzanne C; Rosendaal, Frits R; Reitsma, Pieter H; Lijfering, Willem M
2014-02-01
Selection bias in case-control studies occurs when control selection is inappropriate. However, selection bias due to improper case sampling is less well recognized. We describe how to recognize survivor bias (i.e., selection on exposed cases) and illustrate this with an example study. A case-control study was used to analyze the effect of statins on major bleedings during treatment with vitamin K antagonists. A total of 110 patients who experienced such bleedings were included 18-1,018 days after the bleeding complication and matched to 220 controls. A protective association of major bleeding for exposure to statins (odds ratio [OR]: 0.56; 95% confidence interval: 0.29-1.08) was found, which did not become stronger after adjustment for confounding factors. These observations lead us to suspect survivor bias. To identify this bias, results were stratified on time between bleeding event and inclusion, and repeated for a negative control (an exposure not related to survival): blood group non-O. The ORs for exposure to statins increased gradually to 1.37 with shorter time between outcome and inclusion, whereas ORs for the negative control remained constant, confirming our hypothesis. We recommend the presented method to check for overoptimistic results, that is, survivor bias in case-control studies. Copyright © 2014 Elsevier Inc. All rights reserved.
After a merger: the dilemma of the best leadership approach for nursing.
Porter-O'Grady, T; Bradley, C; Crow, G; Hendrich, A L
1997-01-01
The following case study exemplifies for the nurse leader some of the difficulties involved in making a merger work and selecting the best options to sustain nursing services following the merger. Three nurse leaders look at the case study from a variety of viewpoints and suggest a range of responses that gives the reader an opportunity to consider a selection of insights that best address the issues presented in the case study. All of the respondents have been involved in complex mergers and bring a depth of experience to their review of the case.
The Best Practices for School Transformation: A Multiple-Case Study
ERIC Educational Resources Information Center
Waheed, Zarina; Hussin, Sufean; Bin Megat Daud, Megat Ahmad Kamaluddin
2018-01-01
Purpose: The purpose of this paper is to explore the best practices of school leaders, teachers, pupils, parents and the community in selected transformed schools in Selangor, Malaysia. Design/methodology/approach: This qualitative multiple-case study explores the best practices in two selected transformed schools through in-depth interviews,…
Recruiting Young Volunteers in an Area of Selective Education: A Qualitative Case Study
ERIC Educational Resources Information Center
Dean, Jon
2016-01-01
This article presents findings from a small qualitative case study of a youth volunteering brokerage organisation in England, operating in an area of selective state education. Data show how brokerage workers felt grammar schools managed their students in a concerted way to improve students' chances of attending university. Conversely, workers…
Horigan, V; De Nardi, M; Simons, R R L; Bertolini, S; Crescio, M I; Estrada-Peña, A; Léger, A; Maurella, C; Ru, G; Schuppers, M; Stärk, K D C; Adkin, A
2018-05-01
We present a novel approach of using the multi-criteria pathogen prioritisation methodology as a basis for selecting the most appropriate case studies for a generic risk assessment framework. The approach uses selective criteria to rank exotic animal health pathogens according to the likelihood of introduction and the impact of an outbreak if it occurred in the European Union (EU). Pathogens were evaluated based on their impact on production at the EU level and international trade. A subsequent analysis included criteria of relevance to quantitative risk assessment case study selection, such as the availability of data for parameterisation, the need for further research and the desire for the case studies to cover different routes of transmission. The framework demonstrated is flexible with the ability to adjust both the criteria and their weightings to the user's requirements. A web based tool has been developed using the RStudio shiny apps software, to facilitate this. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.
de Abajo, Francisco José; Rodríguez, Luis Alberto García; Montero, Dolores
1999-01-01
Objective To examine the association between selective serotonin reuptake inhibitors and risk of upper gastrointestinal bleeding. Design Population based case-control study. Setting General practices included in the UK general practice research database. Subjects 1651 incident cases of upper gastrointestinal bleeding and 248 cases of ulcer perforation among patients aged 40 to 79 years between April 1993 and September 1997, and 10 000 controls matched for age, sex, and year that the case was identified. Interventions Review of computer profiles for all potential cases, and an internal validation study to confirm the accuracy of the diagnosis on the basis of the computerised information. Main outcome measures Current use of selective serotonin reuptake inhibitors or other antidepressants within 30 days before the index date. Results Current exposure to selective serotonin reuptake inhibitors was identified in 3.1% (52 of 1651) of patients with upper gastrointestinal bleeding but only 1.0% (95 of 10 000) of controls, giving an adjusted rate ratio of 3.0 (95% confidence interval 2.1 to 4.4). This effect measure was not modified by sex, age, dose, or treatment duration. A crude incidence of 1 case per 8000 prescriptions was estimated. A small association was found with non-selective serotonin reuptake inhibitors (relative risk 1.4, 1.1 to 1.9) but not with antidepressants lacking this inhibitory effect. None of the groups of antidepressants was associated with ulcer perforation. The concurrent use of selective serotonin reuptake inhibitors with non-steroidal anti-inflammatory drugs increased the risk of upper gastrointestinal bleeding beyond the sum of their independent effects (15.6, 6.6 to 36.6). A smaller interaction was also found between selective serotonin reuptake inhibitors and low dose aspirin (7.2, 3.1 to 17.1). Conclusions Selective serotonin reuptake inhibitors increase the risk of upper gastrointestinal bleeding. The absolute effect is, however, moderate and about equivalent to low dose ibuprofen. The concurrent use of non-steroidal anti-inflammatory drugs or aspirin with selective serotonin reuptake inhibitors greatly increases the risk of upper gastrointestinal bleeding. PMID:10531103
Analysis of single nucleotide polymorphisms in case-control studies.
Li, Yonghong; Shiffman, Dov; Oberbauer, Rainer
2011-01-01
Single nucleotide polymorphisms (SNPs) are the most common type of genetic variants in the human genome. SNPs are known to modify susceptibility to complex diseases. We describe and discuss methods used to identify SNPs associated with disease in case-control studies. An outline on study population selection, sample collection and genotyping platforms is presented, complemented by SNP selection, data preprocessing and analysis.
Dexter, Franklin; Epstein, Richard H; Ledolter, Johannes; Dasovich, Susan M; Herman, Jay H; Maga, Joni M; Schwenk, Eric S
2018-05-01
Hospitals review allogeneic red blood cell (RBC) transfusions for appropriateness. Audit criteria have been published that apply to 5 common procedures. We expanded on this work to study the management decision of selecting which cases involving transfusion of at least 1 RBC unit to audit (review) among all surgical procedures, including those previously studied. This retrospective, observational study included 400,000 cases among 1891 different procedures over an 11-year period. There were 12,616 cases with RBC transfusion. We studied the proportions of cases that would be audited based on criteria of nadir hemoglobin (Hb) greater than the hospital's selected transfusion threshold, or absent Hb or missing estimated blood loss (EBL) among procedures with median EBL <500 mL. This threshold EBL was selected because it is approximately the volume removed during the donation of a single unit of whole blood at a blood bank. Missing EBL is important to the audit decision for cases in which the procedures' median EBL is <500 mL because, without an indication of the extent of bleeding, there are insufficient data to assume that there was sufficient blood loss to justify the transfusion. Most cases (>50%) that would be audited and most cases (>50%) with transfusion were among procedures with median EBL <500 mL (P < .0001). Among cases with transfusion and nadir Hb >9 g/dL, the procedure's median EBL was <500 mL for 3.0 times more cases than for procedures having a median EBL ≥500 mL. A greater percentage of cases would be recommended for audit based on missing values for Hb and/or EBL than based on exceeding the Hb threshold among cases of procedures with median EBL ≥500 mL (P < .0001). There were 3.7 times as many cases with transfusion that had missing values for Hb and/or EBL than had a nadir Hb >9 g/dL and median EBL for the procedure ≥500 mL. An automated process to select cases for audit of intraoperative transfusion of RBC needs to consider the median EBL of the procedure, whether the nadir Hb is below the hospital's Hb transfusion threshold for surgical cases, and the absence of either a Hb or entry of the EBL for the case. This conclusion applies to all surgical cases and procedures.
Freeman, Becky; Potente, Sofia; Rock, Vanessa; McIver, Jacqueline
2015-03-30
A great deal of enthusiasm and interest exists in using social media for public health communications, but few research studies have examined its success in promoting and adopting protective health behaviours. To begin to understand how best to develop effective online social marketing campaigns, this paper provides a summary of success factors and key lessons learnt from selected social media campaign case studies. Case study review Methods: A selection of case studies was reviewed for lessons in campaign development, delivery and evaluation from both the corporate and public health sectors. Information about the objective of the campaign, the tactics used and the lessons learnt was extracted from each case study. Lessons learnt from across the case studies were then sorted according to themes. Lessons from the nine case studies selected were categorised into eight themes: planning, use of social media tools, community, content, personal benefits, promotion, costs and challenges. Outcome evaluation data were lacking in the case studies. Overall, the nine case studies show that social media hold promise in changing user behaviours and that social media are highly effective in recruiting participants and motivating them to take small, concrete actions. The case studies also demonstrate that there is room in social media for targeted, inexpensive, small-scale projects, as well as large, well-funded, mass-reach marketing blitzes. Social media campaign process and impact evaluation measures are readily available. Outcome evaluation models and measures are needed to better assess the effectiveness of social media campaigns in changing health behaviours.
ERIC Educational Resources Information Center
Becker, Colleen Gilday
2013-01-01
The purpose of this case study was to examine the School-Wide Positive Behavior Support (SWPBS) impact on five selected student performance factors. A literature review revealed there have been many SWPBS research studies regarding traditional public schools. However, there have not been any published empirical SWPBS studies involving K-12…
Vrijheid, Martine; Deltour, Isabelle; Krewski, Daniel; Sanchez, Marie; Cardis, Elisabeth
2006-07-01
This paper examines the effects of systematic and random errors in recall and of selection bias in case-control studies of mobile phone use and cancer. These sensitivity analyses are based on Monte-Carlo computer simulations and were carried out within the INTERPHONE Study, an international collaborative case-control study in 13 countries. Recall error scenarios simulated plausible values of random and systematic, non-differential and differential recall errors in amount of mobile phone use reported by study subjects. Plausible values for the recall error were obtained from validation studies. Selection bias scenarios assumed varying selection probabilities for cases and controls, mobile phone users, and non-users. Where possible these selection probabilities were based on existing information from non-respondents in INTERPHONE. Simulations used exposure distributions based on existing INTERPHONE data and assumed varying levels of the true risk of brain cancer related to mobile phone use. Results suggest that random recall errors of plausible levels can lead to a large underestimation in the risk of brain cancer associated with mobile phone use. Random errors were found to have larger impact than plausible systematic errors. Differential errors in recall had very little additional impact in the presence of large random errors. Selection bias resulting from underselection of unexposed controls led to J-shaped exposure-response patterns, with risk apparently decreasing at low to moderate exposure levels. The present results, in conjunction with those of the validation studies conducted within the INTERPHONE study, will play an important role in the interpretation of existing and future case-control studies of mobile phone use and cancer risk, including the INTERPHONE study.
The Power of Natural Selection: A Guided Investigation of Three Case Studies
ERIC Educational Resources Information Center
Beachly, William
2010-01-01
I describe a quantitative approach to three case studies in evolution that can be used to challenge college freshmen to explore the power of natural selection and ask questions that foster a deeper understanding of its operation and relevance. Hemochromatosis, the peppered moth, and hominid cranial capacity are investigated with a common algebraic…
ERIC Educational Resources Information Center
Pease, Adam Steven
2012-01-01
The purpose of this study was to develop best practice standards for hiring public school teachers. This standard was developed from the available literature on recruiting, screening, selecting, and hiring high-quality teachers. The targeted and actual hiring processes of a case study district were compared to this teacher hiring standard.…
ERIC Educational Resources Information Center
Cathcart, Stephen Michael
2016-01-01
This mixed method study examines HRD professionals' decision-making processes when making an organizational purchase of training. The study uses a case approach with a degrees of freedom analysis. The data to analyze will examine how HRD professionals in manufacturing select outside vendors human resource development programs for training,…
ERIC Educational Resources Information Center
Powell, Shawn; Dalley, Mahlono
1995-01-01
An identification and treatment model differentiating transient mutism from persistent selective mutism is proposed. The case study of a six-year-old girl is presented, who was treated with a multimodal approach combining behavioral techniques with play therapy and family involvement. At posttreatment and follow-up, she was talking in a manner…
Arsenic Removal from Drinking Water
Web cast presentation covered six topics: 1), Arsenic Chemistry, 2), Technology Selection/Arsenic Demonstration Program, 3), Case Study 1, 4), Case Study 2,5), Case Study 3, and 6), Media Regeneration Project. The presentation consists of material presented at other training sess...
OD in Schools: The State of the Art. Vol. IV: Case Studies. Final Report.
ERIC Educational Resources Information Center
Fullan, Michael; And Others
This volume, the fourth of a five-volume series, contains three onsite case studies of organization development (OD) selected from a sample of 76 school districts. The purpose of the case studies was to analyze in detail different types of OD programs and their use. Each case study represents a different OD focus: case study A involves a survey…
ERIC Educational Resources Information Center
Maharaj-Sharma, Rawatee; Sharma, Amrit
2014-01-01
This case study explored what experiences contribute to the ideas of energy held by 30 purposively selected primary school students from one primary school in Trinidad and Tobago. The 30 students were selected from across all levels of the primary system. The study used the Interview About Events (IAE) approach to explore students' ideas about…
ERIC Educational Resources Information Center
Barnett-Johnson, Kim R.
2009-01-01
The purpose of this case/phenomenological study was to examine a collegiate administrative search and selection process and the experience of an African American woman who was selected to the position of chancellor. A case concerning the search process of a regional campus of Ivy Tech Community College of Indiana was identified and chosen.…
ERIC Educational Resources Information Center
Palmisano, Victoria M.
2012-01-01
This case study sheds light on successful matriculation practices which emerge from the combination of institutional efforts and student needs. In order to discern successful matriculation data was collected in the form of interviews, observations, and documents at a less selective college with a high rate of retention. Mortimer Adler College…
Guidelines for Using Case Studies in the Teaching-Learning Process
ERIC Educational Resources Information Center
McFarlane, Donovan A.
2015-01-01
In this paper, the author expresses concerns regarding the extensive use of case studies in the college classroom and advises college and university faculties to be more careful in their selection and use of case studies as an effective-based method of teaching. The author communicates the important role that case studies play in teaching and…
A Case Study of Project ATHENA: Tactical Level Technological Innovation Aboard the USS Benfold
2014-12-01
case studies , grounded theory research , phenomenological research and narrative research . 13 3. Qualitative Methods : Selection The researcher’s...12 B. THE CASE STUDY METHOD 1. Introduction The case study is a type of qualitative research that enables the researcher to chronicle and...objectives and the research environment ultimately determine the
The Case Study: I'm Looking over a White-Striped Clover--A Case of Natural Selection
ERIC Educational Resources Information Center
Krufka, Alison; Evarts, Susan; Wilson, Chester
2007-01-01
The case presented in this article is an exploration of the process of natural selection using white clover ("Trifolium repens") as an example. In general, two forms of white clover can be found around the world in various habitats. One type has plain green leaves and the other type produces cyanide as a defense against herbivores and…
Reducing selection bias in case-control studies from rare disease registries.
Cole, J Alexander; Taylor, John S; Hangartner, Thomas N; Weinreb, Neal J; Mistry, Pramod K; Khan, Aneal
2011-09-12
In clinical research of rare diseases, where small patient numbers and disease heterogeneity limit study design options, registries are a valuable resource for demographic and outcome information. However, in contrast to prospective, randomized clinical trials, the observational design of registries is prone to introduce selection bias and negatively impact the validity of data analyses. The objective of the study was to demonstrate the utility of case-control matching and the risk-set method in order to control bias in data from a rare disease registry. Data from the International Collaborative Gaucher Group (ICGG) Gaucher Registry were used as an example. A case-control matching analysis using the risk-set method was conducted to identify two groups of patients with type 1 Gaucher disease in the ICGG Gaucher Registry: patients with avascular osteonecrosis (AVN) and those without AVN. The frequency distributions of gender, decade of birth, treatment status, and splenectomy status were presented for cases and controls before and after matching. Odds ratios (and 95% confidence intervals) were calculated for each variable before and after matching. The application of case-control matching methodology results in cohorts of cases (i.e., patients with AVN) and controls (i.e., patients without AVN) who have comparable distributions for four common parameters used in subject selection: gender, year of birth (age), treatment status, and splenectomy status. Matching resulted in odds ratios of approximately 1.00, indicating no bias. We demonstrated bias in case-control selection in subjects from a prototype rare disease registry and used case-control matching to minimize this bias. Therefore, this approach appears useful to study cohorts of heterogeneous patients in rare disease registries.
Observational evidence and strength of evidence domains: case examples
2014-01-01
Background Systematic reviews of healthcare interventions most often focus on randomized controlled trials (RCTs). However, certain circumstances warrant consideration of observational evidence, and such studies are increasingly being included as evidence in systematic reviews. Methods To illustrate the use of observational evidence, we present case examples of systematic reviews in which observational evidence was considered as well as case examples of individual observational studies, and how they demonstrate various strength of evidence domains in accordance with current Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Center (EPC) methods guidance. Results In the presented examples, observational evidence is used when RCTs are infeasible or raise ethical concerns, lack generalizability, or provide insufficient data. Individual study case examples highlight how observational evidence may fulfill required strength of evidence domains, such as study limitations (reduced risk of selection, detection, performance, and attrition); directness; consistency; precision; and reporting bias (publication, selective outcome reporting, and selective analysis reporting), as well as additional domains of dose-response association, plausible confounding that would decrease the observed effect, and strength of association (magnitude of effect). Conclusions The cases highlighted in this paper demonstrate how observational studies may provide moderate to (rarely) high strength evidence in systematic reviews. PMID:24758494
A morphologic analysis of 'naked' islets of Langerhans in lobular atrophy of the pancreas.
Suda, K; Tsukahara, M; Miyake, T; Hirai, S
1994-08-01
The 'naked' islets of Langerhans (NIL) in randomly selected autopsy cases and in cases of chronic alcoholic pancreatitis, cystic fibrosis, and pancreatic carcinoma were studied histopathologically. The NIL were found in 55 of 164 randomly selected cases, with age-related frequency, in 21 of 30 cases of chronic alcoholic pancreatitis, in 2 of 2 cases of cystic fibrosis, and in 25 of 32 cases of pancreatic carcinoma. The NIL were frequently accompanied by ductal alterations: epithelial metaplasia and hyperplasia in randomly selected cases, protein plugs in chronic alcoholic pancreatitis, mucus plugs in cystic fibrosis, and obliterated ducts in pancreatic carcinoma. The NIL in randomly selected cases may have been formed by ductal alterations that caused stenosis of the lumen, those in chronic alcoholic pancreatitis and cystic fibrosis were the result of protein or mucus plugging, and those in pancreatic carcinoma were a result of neoplastic involvement of the distal pancreatic duct. Therefore, the common factor in the development of NIL is thought to be obstruction of the pancreatic duct system, and in cases of NIL that have a multilobular distribution and interinsular fibrosis, a diagnosis of chronic pancreatitis can usually be made.
Djordjevic, V; Bukurov, B; Arsovic, N; Dimitrijevic, M; Jesic, S; Nesic, V; Petrovic, Z
2016-12-01
To evaluate the efficacy of bilateral selective neck dissection of levels II-IV in elective and therapeutic management of the neck as a part of primary surgical treatment of patients with supraglottic laryngeal cancer and clinically negative cervical findings (N0). Institutional, observational, case-control study with historic control of patients who underwent primary supraglottic tumour surgery, and a prospective cohort of patient, who underwent, besides the operation of primary tumour, bilateral selective neck dissection (level II-IV). University, tertiary level hospital, national referral centre. The study included 193 patients with supraglottic cancer and without palpable or ultrasound positive cervical findings who were surgically treated from 1988 to 2005. Besides the operation of primary tumour, all patients in the study group underwent bilateral selective neck dissection (level II-IV). Patients in the control group (N = 51) underwent primary tumour operation only and were followed up regularly. In cases with postoperative regional recurrences, the radical neck dissection was performed. All patients with histopathological confirmation of occult metastases were administered radiotherapy treatment (60 Gy) in the postoperative period. Five-year overall survival rate. Occult cervical metastases were found in 18% of patients. They were present in level II in 77.5%, in level III in 20% of cases and in one patient in level IV (2.5%); the extracapsular spread was observed in 20% of cases. Postoperative regional metastases were found in 4.15% of cases in the study group, and in 11.8% in the control group, which proved to be significantly higher. The five-year overall survival rate showed no significant difference between the study group and the control group. The incidence of postoperative regional recurrences could be reduced by performing bilateral selective neck dissection simultaneously with primary tumour operation, but with no influence on the survival rate. © 2015 John Wiley & Sons Ltd.
How Expert Special Educators Effectively Negotiate Their Job Demands
ERIC Educational Resources Information Center
Ortogero, Shawna P.; Black, Rhonda S.; Cook, Bryan G.
2017-01-01
This qualitative case study explored how three expert secondary special education teachers in Hawaii successfully negotiated their job demands. Purposeful sampling was used to select one secondary school on the Leeward coast of Oahu. We used reputational-case sampling to select participants that fit Dreyfus and Dreyfus' (1980) expert theoretical…
Treatment outcomes in 3 modes of orthodontic practice.
Poulton, Donald R; Baumrind, Sheldon; Vlaskalic, Vicki
2002-02-01
This study examined differences in pretreatment severity and treatment outcome among orthodontic patients treated in 3 different practice-management modes. Samples of pretreatment (T1) and end of treatment (T2) study casts were selected from traditional private practices (TPP, 3 offices, 81 cases), a dental corporation (COMP, 2 offices, 53 cases), and a dental management service organization (DMSO, 1 office, 36 cases). Orthodontic specialists had treated all patients. Cases were initially selected on a consecutive start basis. From each practice, the first 30 cases satisfying the study criteria were included in the sample. The T1 and T2 study casts were evaluated with the PAR and HLD indexes. The PAR and HLD indexes showed a high level of agreement on T1 cast scores but not on the T2 casts. Mean T1 scores were highest in the COMP cases, followed by the DMSO and the TPP cases. T2 scores were lowest in the TPP cases, followed by the DMSO and the COMP cases. The percentage of PAR score reduction showed that, in all 3 modes, patients were treated to a high standard.
ERIC Educational Resources Information Center
Paulissen, Margaret O.; And Others
The Teacher Induction Study investigated 2 state-mandated beginning teacher programs and examined the translation of state policy by 4 school districts, 13 individual schools, and 32 classrooms. From the case histories of 16 teams, 2 case histories were selected for further study. One case illustrated how institutional factors influenced team…
ERIC Educational Resources Information Center
Fallek, Max
This collection of case studies is intended for use in a course in setting up a small business. The first, a case study of the process of setting up a service company, covers analyzing the pros and cons of starting one's own business, assessing the competition and local market, and selecting a site for and financing the business. The principal…
Selection and Presentation of Imaging Figures in the Medical Literature
Siontis, George C. M.; Patsopoulos, Nikolaos A.; Vlahos, Antonios P.; Ioannidis, John P. A.
2010-01-01
Background Images are important for conveying information, but there is no empirical evidence on whether imaging figures are properly selected and presented in the published medical literature. We therefore evaluated the selection and presentation of radiological imaging figures in major medical journals. Methodology/Principal Findings We analyzed articles published in 2005 in 12 major general and specialty medical journals that had radiological imaging figures. For each figure, we recorded information on selection, study population, provision of quantitative measurements, color scales and contrast use. Overall, 417 images from 212 articles were analyzed. Any comment/hint on image selection was made in 44 (11%) images (range 0–50% across the 12 journals) and another 37 (9%) (range 0–60%) showed both a normal and abnormal appearance. In 108 images (26%) (range 0–43%) it was unclear whether the image came from the presented study population. Eighty-three images (20%) (range 0–60%) had any quantitative or ordered categorical value on a measure of interest. Information on the distribution of the measure of interest in the study population was given in 59 cases. For 43 images (range 0–40%), a quantitative measurement was provided for the depicted case and the distribution of values in the study population was also available; in those 43 cases there was no over-representation of extreme than average cases (p = 0.37). Significance The selection and presentation of images in the medical literature is often insufficiently documented; quantitative data are sparse and difficult to place in context. PMID:20526360
An Exploration of Mathematics Graduate Teaching Assistants' Teaching Philosophies: A Case Study
ERIC Educational Resources Information Center
Nepal, Kedar Mani
2014-01-01
This multi-case study is an exploration of mathematics graduate teaching assistants' teaching philosophies. It focused on the cases of four purposefully selected beginning mathematics graduate teaching assistants (MGTAs) including two domestic and two international MGTAs. Using qualitative research methods, this dissertation study focused on the…
ERIC Educational Resources Information Center
McCarthy, Maureen E.; And Others
Designed to provide private sector employers with the practical information necessary to select and then to design and implement work sharing arrangements, this book presents case studies of some 36 work sharing programs. Topics covered in the case studies include the circumstances leading to adoption of the program, details of compensation and…
75 FR 65355 - Agency Forms Undergoing Paperwork Reduction Act Review
Federal Register 2010, 2011, 2012, 2013, 2014
2010-10-22
... Project Case Studies of Communities and States Funded under Community Activities under the Communities..., system, and environmental changes. Intensive case studies will be conducted with 24 sites: Six ARRA... Act. The case study sites will be selected to include a mix of State or community characteristics...
An efficient sampling strategy for selection of biobank samples using risk scores.
Björk, Jonas; Malmqvist, Ebba; Rylander, Lars; Rignell-Hydbom, Anna
2017-07-01
The aim of this study was to suggest a new sample-selection strategy based on risk scores in case-control studies with biobank data. An ongoing Swedish case-control study on fetal exposure to endocrine disruptors and overweight in early childhood was used as the empirical example. Cases were defined as children with a body mass index (BMI) ⩾18 kg/m 2 ( n=545) at four years of age, and controls as children with a BMI of ⩽17 kg/m 2 ( n=4472 available). The risk of being overweight was modelled using logistic regression based on available covariates from the health examination and prior to selecting samples from the biobank. A risk score was estimated for each child and categorised as low (0-5%), medium (6-13%) or high (⩾14%) risk of being overweight. The final risk-score model, with smoking during pregnancy ( p=0.001), birth weight ( p<0.001), BMI of both parents ( p<0.001 for both), type of residence ( p=0.04) and economic situation ( p=0.12), yielded an area under the receiver operating characteristic curve of 67% ( n=3945 with complete data). The case group ( n=416) had the following risk-score profile: low (12%), medium (46%) and high risk (43%). Twice as many controls were selected from each risk group, with further matching on sex. Computer simulations showed that the proposed selection strategy with stratification on risk scores yielded consistent improvements in statistical precision. Using risk scores based on available survey or register data as a basis for sample selection may improve possibilities to study heterogeneity of exposure effects in biobank-based studies.
Simultaneous weak measurement of angular and spatial Goos-Hänchen and Imbert-Fedorov shifts
NASA Astrophysics Data System (ADS)
Prajapati, Chandravati; Viswanathan, Nirmal K.
2017-10-01
We propose and demonstrate the weak measurement scheme to simultaneously measure the amplified angular and spatial contributions to the Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts, due to transmission through a glass plate. We have studied two cases of post-selection using a polarizer in the first case and a quarter-wave plate (QWP)-polarizer combination in the second case. The two cases are analyzed theoretically using Jones calculus of polarization formalism and the results are verified experimentally. In the first case of post-selection, the projection of the polarizer at +/- {{Δ }} away from the crossed position amplifies the angular GH and IF shifts, while in the second case of post-selection, the projection of QWP at +/- {{Δ }} and polarizer kept fixed measures the polarization ellipticity in the beam and thus amplifies the spatial shift along with the angular shift simultaneously, for {{Δ }}\\ll 1.
Akgün, Taylan; Tanboğa, Ibrahim Halil; Oduncu, Vecih; Kurt, Mustafa; Cimen, Arif Oğuzhan; Bitigen, Atila
2012-09-01
Selective cannulation of the right coronary artery (RCA) in the anomalous aortic origin of the RCA is technically difficult and challenging. In this study, we tested the success of RCA cannulation with a reshaped left Judkins catheter in cases of difficult selective cannulation. The study population consisted of 837 consecutive patients (456 male, 381 female) that were admitted to our hospital with stable angina pectoris and acute coronary syndrome between October 1 and December 31, 2011. In cases where RCA cannulation was difficult, the 10 centimeter section of the left Judkins proximal to the secondary curve was reshaped by hand to form an inward slope. The secondary curve angle was increased to approximately 100 degrees and the primary curve angle was adjusted to 120 degrees. Then, we attempted to perform selective RCA cannulation. In 49 of the 837 patients, selective RCA cannulation was unsuccessful with the right Judkins catheter. In 42 of these 49 (86%) cases, the RCA was cannulated with the reshaped left Judkins. We failed to cannulate the right coronary in two cases with downward angulation, one with upward angulation, one with high take-off origin, and one with anterior origin. A multipurpose, internal mammary artery, left Amplatz 1, and right Amplatz 1 catheter were used for cannulation in these cases, respectively. There was no angina, nor were there electrocardiographic or hemodynamic changes during the procedure. In cases where the selective cannulation of the RCA is difficult, using a reshaped left Judkins may be a successful and cost-effective method of selective cannulation.
Immediate Implants: Clinical Guidelines for Esthetic Outcomes
Javaid, Mohammad A.; Khurshid, Zohaib; Zafar, Muhammad S.; Najeeb, Shariq
2016-01-01
Research has shown that tooth loss results in morphological changes in alveolar ridge that may influence the subsequent implant placement. Immediate implant placement was introduced as a possible means to limit bone resorption and reduce the number of surgical procedures following tooth extraction. Histological and clinical evidence from human clinical studies showing efficacy of immediate implants has come to light over the last decade or so. However, immediate implant placement is a challenging surgical procedure and requires proper case selection and surgical technique. Furthermore, there appears to be a lack of clinical guidelines for immediate implant placement case selection. Therefore, the aim of this mini-review is to analyze critical evidence from human studies in order to establish clinical guidelines which may help clinicians in case selection when considering immediate implant placement protocol. PMID:29563463
Fullerton, Kathleen E.; Scallan, Elaine; Kirk, Martyn D.; Mahon, Barbara E.; Angulo, Frederick J.; de Valk, Henriette; van Pelt, Wilfrid; Gauci, Charmaine; Hauri, Anja M.; Majowicz, Shannon; O’Brien, Sarah J.
2015-01-01
Epidemiologists have used case-control studies to investigate enteric disease outbreaks for many decades. Increasingly, case-control studies are also used to investigate risk factors for sporadic (not outbreak-associated) disease. While the same basic approach is used, there are important differences between outbreak and sporadic disease settings that need to be considered in the design and implementation of the case-control study for sporadic disease. Through the International Collaboration on Enteric Disease “Burden of Illness” Studies (the International Collaboration), we reviewed 79 case-control studies of sporadic enteric infections caused by nine pathogens that were conducted in 22 countries and published from 1990 through to 2009. We highlight important methodological and study design issues (including case definition, control selection, and exposure assessment) and discuss how approaches to the study of sporadic enteric disease have changed over the last 20 years (e.g., making use of more sensitive case definitions, databases of controls, and computer-assisted interviewing). As our understanding of sporadic enteric infections grows, methods and topics for case-control studies are expected to continue to evolve; for example, advances in understanding of the role of immunity can be used to improve control selection, the apparent protective effects of certain foods can be further explored, and case-control studies can be used to provide population-based measures of the burden of disease. PMID:22443481
Phenomenology and treatment of selective mutism.
Kumpulainen, Kirsti
2002-01-01
Selective mutism is a multidimensional childhood disorder in which, according to the most recent studies, biologically mediated temperament and anxiety components seem to play a major role. Several psychotherapy methods have been reported in case studies to be useful, but the disorder is commonly seen to be resistant to change, particularly in cases of long duration. Currently, behaviour modification and other cognitive methods, together with cooperation with the family and the school personnel, are recommended in the treatment of selective mutism. Selective serotonin reuptake inhibitors and selective monoamine oxidase inhibitors have also been reported to be helpful when treating children with selective mutism. At the moment, pharmacotherapy cannot be recommended as the treatment of first choice but if other methods of treatment are not helpful, medication can be included in the treatment scheme. Comprehensive evaluation and treatment of possible primary and comorbid problems that require treatment are also essential.
Kondo, Kyoko; Suzuki, Kanzo; Washio, Masakazu; Ohfuji, Satoko; Fukushima, Wakaba; Maeda, Akiko; Hirota, Yoshio
2017-08-24
We conducted a case-control study to elucidate associations between pneumonia in elderly individuals and 23-valent pneumococcal polysaccharide vaccine (PPSV23) and seasonal influenza vaccine (influenza vaccine). Here, we examined selection of controls in our study using an analytic epidemiology approach. The study period was from October 1, 2009 through September 30, 2014. Cases comprised ≥65-year-old patients newly diagnosed with pneumonia. For every case with pneumonia, two patients with other diseases (one respiratory medicine, one non-respiratory medicine) who were sex-, age-, visit date- and visit hospital-matched were selected as controls. Odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for pneumonia were calculated using conditional logistic regression model. Similar analyses were also conducted based on the clinical department of controls. Analysis was conducted in 234 cases and 438 controls. Effectiveness of pneumococcal vaccination or influenza vaccination against pneumonia was not detected. Proportions of either vaccination in controls were greater among respiratory medicine (pneumococcal vaccine, 38%; influenza vaccine, 55%) than among non-respiratory medicine (23%; 48%). Analysis using controls restricted to respiratory medicine showed marginally significant effectiveness of pneumococcal vaccination (OR, 0.59; 95%CI, 0.34-1.03; P=0.064) and influenza vaccination (0.64; 0.40-1.04; 0.072). However, this effectiveness might have been overestimated by selection bias of controls, as pneumonia cases are not necessarily respiratory medicine patients. In the analysis using controls restricted to non-respiratory medicine, OR of pneumococcal vaccination for pneumonia was close to 1, presumably because the proportion of pneumococcal vaccination was higher in cases than in controls. Because pneumococcal vaccine was not routinely administered during the study period, differences in recommendations of vaccination by physician in different clinical departments might have greatly affected vaccination proportions. When we select controls, we should consider the background factors (underlying diseases, clinical department, etc.) which affect physicians' recommendation of vaccination. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
Bakhriansyah, Mohammad; Souverein, Patrick C; de Boer, Anthonius; Klungel, Olaf H
2017-10-01
To assess the risk of gastrointestinal perforation, ulcers, or bleeding (PUB) associated with the use of conventional nonsteroidal anti-inflammatory drugs (NSAIDs) with proton pump inhibitors (PPIs) and selective COX-2 inhibitors, with or without PPIs compared with conventional NSAIDs. A case-control study was performed within conventional NSAIDs and/or selective COX-2 inhibitors users identified from the Dutch PHARMO Record Linkage System in the period 1998-2012. Cases were patients aged ≥18 years with a first hospital admission for PUB. For each case, up to four controls were matched for age and sex at the date a case was hospitalized (index date). Logistic regression analysis was used to calculate odds ratios (ORs). At the index date, 2634 cases and 5074 controls were current users of conventional NSAIDs or selective COX-2 inhibitors. Compared with conventional NSAIDs, selective COX-2 inhibitors with PPIs had the lowest risk of PUB (adjusted OR 0.51, 95% confidence interval [CI]: 0.35-0.73) followed by selective COX-2 inhibitors (adjusted OR 0.66, 95%CI: 0.48-0.89) and conventional NSAIDs with PPIs (adjusted OR 0.79, 95%CI: 0.68-0.92). Compared with conventional NSAIDs, the risk of PUB was lower for those aged ≥75 years taking conventional NSAIDs with PPIs compared with younger patients (adjusted interaction OR 0.79, 95%CI: 0.64-0.99). However, those aged ≥75 years taking selective COX-2 inhibitors, the risk was higher compared with younger patients (adjusted interaction OR 1.22, 95%CI: 1.01-1.47). Selective COX-2 inhibitors with PPIs, selective COX-2 inhibitors, and conventional NSAIDs with PPIs were associated with lower risks of PUB compared with conventional NSAIDs. These effects were modified by age. © 2017 The Authors. Pharmacoepidemiology & Drug Safety Published by John Wiley & Sons Ltd. © 2017 The Authors. Pharmacoepidemiology & Drug Safety Published by John Wiley & Sons Ltd.
Pathway Analysis and the Search for Causal Mechanisms
ERIC Educational Resources Information Center
Weller, Nicholas; Barnes, Jeb
2016-01-01
The study of causal mechanisms interests scholars across the social sciences. Case studies can be a valuable tool in developing knowledge and hypotheses about how causal mechanisms function. The usefulness of case studies in the search for causal mechanisms depends on effective case selection, and there are few existing guidelines for selecting…
Carrera, D; de la Flor, M; Galera, J; Amillano, K; Gomez, M; Izquierdo, V; Aguilar, E; López, S; Martínez, M; Martínez, S; Serra, J M; Pérez, M; Martin, L
2016-01-01
The aim of our study was to evaluate sentinel lymph node biopsy as a diagnostic test for assessing the presence of residual metastatic axillary lymph nodes after neoadjuvant chemotherapy, replacing the need for a lymphadenectomy in negative selective lymph node biopsy patients. A multicentre, diagnostic validation study was conducted in the province of Tarragona, on women with T1-T3, N1-N2 breast cancer, who presented with a complete axillary response after neoadjuvant chemotherapy. Study procedures consisted of performing an selective lymph node biopsy followed by lymphadenectomy. A total of 53 women were included in the study. Surgical detection rate was 90.5% (no sentinel node found in 5 patients). Histopathological analysis of the lymphadenectomy showed complete disease regression of axillary nodes in 35.4% (17/48) of the patients, and residual axillary node involvement in 64.6% (31/48) of them. In lymphadenectomy positive patients, 28 had a positive selective lymph node biopsy (true positive), while 3 had a negative selective lymph node biopsy (false negative). Of the 28 true selective lymph node biopsy positives, the sentinel node was the only positive node in 10 cases. All lymphadenectomy negative cases were selective lymph node biopsy negative. These data yield a sensitivity of 93.5%, a false negative rate of 9.7%, and a global test efficiency of 93.7%. Selective lymph node biopsy after chemotherapy in patients with a complete axillary response provides valid and reliable information regarding axillary status after neoadjuvant treatment, and might prevent lymphadenectomy in cases with negative selective lymph node biopsy. Copyright © 2016 Elsevier España, S.L.U. and SEMNIM. All rights reserved.
Optimal selection of markers for validation or replication from genome-wide association studies.
Greenwood, Celia M T; Rangrej, Jagadish; Sun, Lei
2007-07-01
With reductions in genotyping costs and the fast pace of improvements in genotyping technology, it is not uncommon for the individuals in a single study to undergo genotyping using several different platforms, where each platform may contain different numbers of markers selected via different criteria. For example, a set of cases and controls may be genotyped at markers in a small set of carefully selected candidate genes, and shortly thereafter, the same cases and controls may be used for a genome-wide single nucleotide polymorphism (SNP) association study. After such initial investigations, often, a subset of "interesting" markers is selected for validation or replication. Specifically, by validation, we refer to the investigation of associations between the selected subset of markers and the disease in independent data. However, it is not obvious how to choose the best set of markers for this validation. There may be a prior expectation that some sets of genotyping data are more likely to contain real associations. For example, it may be more likely for markers in plausible candidate genes to show disease associations than markers in a genome-wide scan. Hence, it would be desirable to select proportionally more markers from the candidate gene set. When a fixed number of markers are selected for validation, we propose an approach for identifying an optimal marker-selection configuration by basing the approach on minimizing the stratified false discovery rate. We illustrate this approach using a case-control study of colorectal cancer from Ontario, Canada, and we show that this approach leads to substantial reductions in the estimated false discovery rates in the Ontario dataset for the selected markers, as well as reductions in the expected false discovery rates for the proposed validation dataset. Copyright 2007 Wiley-Liss, Inc.
Cronin-Fenton, Deirdre P; Pedersen, Lars; Lash, Timothy L; Friis, Søren; Baron, John A; Sørensen, Henrik T
2010-01-01
Non-steroidal anti-inflammatory drugs (NSAIDs) prevent the growth of mammary tumours in animal models. Two population-based case-control studies suggest a reduced risk of breast cancer associated with selective cyclooxygenase-2 (sCox-2) inhibitor use, but data regarding the association between breast cancer occurrence and use of non-selective NSAIDs are conflicting. We conducted a population-based case-control study using Danish healthcare databases to examine if use of NSAIDs, including sCox-2 inhibitors, was associated with a reduced risk of breast cancer. We included 8,195 incident breast cancer cases diagnosed in 1991 through 2006 and 81,950 population controls. Overall, we found no reduced breast cancer risk in ever users (>2 prescriptions) of sCox-2 inhibitors (odds ratio (OR) = 1.08, 95% confidence interval (95% CI) = 0.99, 1.18), aspirin (OR = 0.98, 95% CI = 0.90-1.07), or non-selective NSAIDs OR = 1.04, (95% CI = 0.98, 1.10)). Recent use (>2 prescriptions within two years of index date) of sCox-2 inhibitors, aspirin, or non-selective NSAIDs was likewise not associated with breast cancer risk (Ors = 1.06 (95% CI = 0.96, 1.18), 0.96 (95% CI = 0.87, 1.06) and 0.99 (95% CI = 0.85, 1.16), respectively). Risk estimates by duration (<10, 10 to 15, 15+ years) or intensity (low/medium/high) of NSAID use were also close to unity. Regardless of intensity, shorter or long-term NSAID use was not significantly associated with breast cancer risk. Overall, we found no compelling evidence of a reduced risk of breast cancer associated with use of sCox-2 inhibitors, aspirin, or non-selective NSAIDs.
Assessing different measures of population-level vaccine protection using a case-control study.
Ali, Mohammad; You, Young Ae; Kanungo, Suman; Manna, Byomkesh; Deen, Jacqueline L; Lopez, Anna Lena; Wierzba, Thomas F; Bhattacharya, Sujit K; Sur, Dipika; Clemens, John D
2015-11-27
Case-control studies have not been examined for their utility in assessing population-level vaccine protection in individually randomized trials. We used the data of a randomized, placebo-controlled trial of a cholera vaccine to compare the results of case-control analyses with those of cohort analyses. Cases of cholera were selected from the trial population followed for three years following dosing. For each case, we selected 4 age-matched controls who had not developed cholera. For each case and control, GIS was used to calculate vaccine coverage of individuals in a surrounding "virtual" cluster. Specific selection strategies were used to evaluate the vaccine protective effects. 66,900 out of 108,389 individuals received two doses of the assigned regimen. For direct protection among subjects in low vaccine coverage clusters, we observed 78% (95% CI: 47-91%) protection in a cohort analysis and 84% (95% CI: 60-94%) in case-control analysis after adjusting for confounding factors. Using our GIS-based approach, estimated indirect protection was 52% (95% CI: 10-74%) in cohort and 76% (95% CI: 47-89%) in case control analysis. Estimates of total and overall effectiveness were similar for cohort and case-control analyses. The findings show that case-control analyses of individually randomized vaccine trials may be used to evaluate direct as well as population-level vaccine protection. Copyright © 2015. Published by Elsevier Ltd.
2005-03-01
qualitative research methods , a case study approach was selected to conduct this research . “A case study can be defined as an empirical study ... qualitative in nature, and also described the qualitative research method chosen as a case study . From 49 there, data collection was focused upon... qualitative nature of the research , a qualitative design was used to conduct the
A Data Management System for Multi-Phase Case-Control Studies
Gibeau, Joanne M.; Steinfeldt, Lois C.; Stine, Mark J.; Tullis, Katherine V.; Lynch, H. Keith
1983-01-01
The design of a computerized system for the management of data in multi-phase epidemiologic case-control studies is described. Typical study phases include case-control selection, abstracting of data from medical records, and interview of study subjects or next of kin. In consultation with project personnel, requirements for the system were established: integration of data from all study phases into one data base, accurate follow-up of subjects through the study, sophisticated data editing capabilities, ready accessibility of specified programs to project personnel, and generation of current status and exception reports for project managment. SIR (Scientific Information Retrieval), a commercially available data base management system, was selected as the foundation of this system. The system forms a comprehensive data management system applicable to many types of public health research studies.
EPA sought advice from stakeholders regarding potential case studies, stakeholder were invited to provide suggestions and refinements to the prioritization of criteria and information listed in Table 1 of the document.
Case Studies on Educational Administration. Third Edition.
ERIC Educational Resources Information Center
Kowalski, Theodore J.
This book contains 24 case studies selected to demonstrate the different types of challenges in contemporary educational leadership. It is intended to help prospective administrators develop decision-making skills. The cases are quite complex with multiple viewpoints and aspects. They represent a range of problems encountered by practitioners in…
Stephen, Reejis; Boxwala, Aziz; Gertman, Paul
2003-01-01
Data from Clinical Data Warehouses (CDWs) can be used for retrospective studies and for benchmarking. However, automated identification of cases from large datasets containing data items in free text fields is challenging. We developed an algorithm for categorizing pediatric patients presenting with respiratory distress into Bronchiolitis, Bacterial pneumonia and Asthma using clinical variables from a CDW. A feasibility study of this approach indicates that case selection may be automated.
ERIC Educational Resources Information Center
Richards, Gretchen M.
2012-01-01
This multisite case study examined how institutional and university counselor policies effectively respond to cyber violent acts. Stake's (2006) multisite case study methodology was used to identify seven themes from current literature. Two sites with four participants were selected. The participants included two counseling directors and the…
Perspectives on Distance Education. Quality Assurance in Higher Education: Selected Case Studies.
ERIC Educational Resources Information Center
Tait, Alan, Ed.
This publication consists of a set of case studies of quality assurance practices in distance teaching universities. The case studies are particularly relevant at a time when universities in many parts of the world, both new and established distance teaching universities, are placing great emphasis on reviewing and revising what they do in…
Case Study: Revising a Formal Case Study Presentation as an Independent Research Project
ERIC Educational Resources Information Center
Field, Patrick R.
2013-01-01
This article examines the process of researching and revising a case study presentation on an individual who experienced anesthetic awareness during an abdominal surgery and eventually committed suicide. Topics addressed include the author's selection of an undergraduate student with a science and teaching background to work on the case…
Tan, Maxine; Aghaei, Faranak; Wang, Yunzhi; Zheng, Bin
2017-01-01
The purpose of this study is to evaluate a new method to improve performance of computer-aided detection (CAD) schemes of screening mammograms with two approaches. In the first approach, we developed a new case based CAD scheme using a set of optimally selected global mammographic density, texture, spiculation, and structural similarity features computed from all four full-field digital mammography (FFDM) images of the craniocaudal (CC) and mediolateral oblique (MLO) views by using a modified fast and accurate sequential floating forward selection feature selection algorithm. Selected features were then applied to a “scoring fusion” artificial neural network (ANN) classification scheme to produce a final case based risk score. In the second approach, we combined the case based risk score with the conventional lesion based scores of a conventional lesion based CAD scheme using a new adaptive cueing method that is integrated with the case based risk scores. We evaluated our methods using a ten-fold cross-validation scheme on 924 cases (476 cancer and 448 recalled or negative), whereby each case had all four images from the CC and MLO views. The area under the receiver operating characteristic curve was AUC = 0.793±0.015 and the odds ratio monotonically increased from 1 to 37.21 as CAD-generated case based detection scores increased. Using the new adaptive cueing method, the region based and case based sensitivities of the conventional CAD scheme at a false positive rate of 0.71 per image increased by 2.4% and 0.8%, respectively. The study demonstrated that supplementary information can be derived by computing global mammographic density image features to improve CAD-cueing performance on the suspicious mammographic lesions. PMID:27997380
The West. Grade Five (Unit V). Resource Unit. Project Social Studies.
ERIC Educational Resources Information Center
Minnesota Univ., Minneapolis. Project Social Studies Curriculum Center.
This resource unit for 5th graders includes three case studies and a sub-unit on the West as a region. Three sequent occupance case studies which are suggestive, rather than prescriptive, comprise the first part of the unit. Teachers may decide to select only one for an in-depth study or may decide to design a case study modeled after this…
Tagliafico, Alberto Stefano; Bignotti, Bianca; Rossi, Federica; Signori, Alessio; Sormani, Maria Pia; Valdora, Francesca; Calabrese, Massimo; Houssami, Nehmat
2016-08-01
To estimate sensitivity and specificity of CESM for breast cancer diagnosis. Systematic review and meta-analysis of the accuracy of CESM in finding breast cancer in highly selected women. We estimated summary receiver operating characteristic curves, sensitivity and specificity according to quality criteria with QUADAS-2. Six hundred four studies were retrieved, 8 of these reporting on 920 patients with 994 lesions, were eligible for inclusion. Estimated sensitivity from all studies was: 0.98 (95% CI: 0.96-1.00). Specificity was estimated from six studies reporting raw data: 0.58 (95% CI: 0.38-0.77). The majority of studies were scored as at high risk of bias due to the very selected populations. CESM has a high sensitivity but very low specificity. The source studies were based on highly selected case series and prone to selection bias. High-quality studies are required to assess the accuracy of CESM in unselected cases. Copyright © 2016 Elsevier Ltd. All rights reserved.
Jiang, Jingmei; Liu, Boqi; Nasca, Philip C; Han, Wei; Zou, Xiaonong; Zeng, Xianjia; Tian, Xiaobing; Wu, Yanping; Zhao, Ping; Li, Junyao
2009-10-28
To assess the validation of a novel control selection design by comparing the consistency between the new design and a routine design in a large case-control study that was incorporated into a nationwide mortality survey in China. A nationwide mortality study was conducted during 1989-1991. Surviving spouses or other relatives of all adults who died during 1986-1988 provided detailed information about their own as well as the deceased person's smoking history. In this study, 130,079 males who died of various smoking-related cancers at age 35 or over were taken as cases, while 103,248 male surviving spouses (same age range with cases) of women who died during the same period and 49,331 males who died from causes other than those related to smoking were used as control group 1 and control group 2, respectively. Consistency in the results when comparing cases with each of the control groups was assessed. Consistency in the results was observed in the analyses using different control groups although cancer deaths varied with region and age. Equivalence could be ascertained using a 15% criterion in most cancer deaths which had high death rates in urban areas, but they were uncertain for most cancers in rural areas irrespective of whether the hypothesis testing showed significant differences or not. Sex-matched living spouse control design as an alternative control selection for a case-control study is valid and feasible, and the basic principles of the equivalence study are also supported by epidemiological survey data.
Case Studies Nested in Fuzzy-Set QCA on Sufficiency: Formalizing Case Selection and Causal Inference
ERIC Educational Resources Information Center
Schneider, Carsten Q.; Rohlfing, Ingo
2016-01-01
Qualitative Comparative Analysis (QCA) is a method for cross-case analyses that works best when complemented with follow-up case studies focusing on the causal quality of the solution and its constitutive terms, the underlying causal mechanisms, and potentially omitted conditions. The anchorage of QCA in set theory demands criteria for follow-up…
Clinical Research Methodology 2: Observational Clinical Research.
Sessler, Daniel I; Imrey, Peter B
2015-10-01
Case-control and cohort studies are invaluable research tools and provide the strongest feasible research designs for addressing some questions. Case-control studies usually involve retrospective data collection. Cohort studies can involve retrospective, ambidirectional, or prospective data collection. Observational studies are subject to errors attributable to selection bias, confounding, measurement bias, and reverse causation-in addition to errors of chance. Confounding can be statistically controlled to the extent that potential factors are known and accurately measured, but, in practice, bias and unknown confounders usually remain additional potential sources of error, often of unknown magnitude and clinical impact. Causality-the most clinically useful relation between exposure and outcome-can rarely be definitively determined from observational studies because intentional, controlled manipulations of exposures are not involved. In this article, we review several types of observational clinical research: case series, comparative case-control and cohort studies, and hybrid designs in which case-control analyses are performed on selected members of cohorts. We also discuss the analytic issues that arise when groups to be compared in an observational study, such as patients receiving different therapies, are not comparable in other respects.
Using step and path selection functions for estimating resistance to movement: Pumas as a case study
Katherine A. Zeller; Kevin McGarigal; Samuel A. Cushman; Paul Beier; T. Winston Vickers; Walter M. Boyce
2015-01-01
GPS telemetry collars and their ability to acquire accurate and consistently frequent locations have increased the use of step selection functions (SSFs) and path selection functions (PathSFs) for studying animal movement and estimating resistance. However, previously published SSFs and PathSFs often do not accommodate multiple scales or multiscale modeling....
van der Waal, Daniëlle; Broeders, Mireille J M; Verbeek, André L M; Duffy, Stephen W; Moss, Sue M
2015-07-01
Ongoing breast cancer screening programs can only be evaluated using observational study designs. Most studies have observed a reduction in breast cancer mortality, but design differences appear to have resulted in different estimates. Direct comparison of case-control and trial analyses gives more insight into this variation. Here, we performed case-control analyses within the randomized UK Age Trial. The Age Trial assessed the effect of screening on breast cancer mortality in women ages 40-49 years. In our approach, case subjects were defined as breast cancer deaths between trial entry (1991-1997) and 2004. Women were ages 39-41 years at entry. For every case subject, five control subjects were selected. All case subjects were included in analyses of screening invitation (356 case subjects, 1,780 controls), whereas analyses of attendance were restricted to women invited to screening (105 case subjects, 525 age-matched controls). Odds ratios (OR) were estimated with conditional logistic regression. We used and compared two methods to correct for self-selection bias. Screening invitation resulted in a breast cancer mortality reduction of 17% (95% confidence interval [CI]: -36%, +6%), similar to trial results. Different exposure definitions and self-selection adjustments influenced the observed breast cancer mortality reduction. Depending on the method, "ever screened" appeared to be associated with a small reduction (OR: 0.86, 95% CI: 0.40, 1.89) or no reduction (OR: 1.02, 95% CI: 0.48, 2.14) using the two methods of correction. Recent attendance resulted in an adjusted mortality reduction of 36% (95% CI: -69%, +31%) or 45% (95% CI: -71%, +5%). Observational studies, and particularly case-control studies, are an important monitoring tool for breast cancer screening programs. The focus should be on diminishing bias in observational studies and gaining a better understanding of the influence of study design on estimates of mortality reduction.
2017-06-01
17 III. METHODOLOGY ..............................................................................................19 A... CASE STUDY SELECTION ..................................................................19 B. RESEARCH APPROACH...20 IV. GLOBAL WAR ON TERRORISM CASE STUDY .........................................21 A. AFGHANISTAN
Iodinated Contrast Media-Induced Thyroid Dysfunction in Euthyroid Nodular Goiter Patients.
Kornelius, Edy; Chiou, Jeng-Yuan; Yang, Yi-Sun; Lo, Shih-Chang; Peng, Chiung-Huei; Lai, Yung-Rung; Huang, Chien-Ning
2016-08-01
The risks of thyroid dysfunction after iodinated contrast media exposure in patients with euthyroid nodular goiter are largely unknown. This observational, retrospective cohort study included a random selection of one million people in Taiwan. All patients with iodinated contrast media exposure during this study period were selected. Patients with euthyroid nodular goiter were identified as cases, while patients without thyroid nodule were selected as controls. We followed these patients until the first event of thyroid dysfunction including hyperthyroidism or hypothyroidism after iodinated contrast media exposure. A total of 334 cases and 2672 matched controls were selected in this study. The mean age of cases and controls were 58.6 and 58.4 years old, and mean follow-up durations were 2.1 and 2 years respectively. After adjustment, patients with euthyroid nodular goiter had a higher risk of thyroid dysfunction (hazard ratio 5.43, [confidence interval (CI) 3.01-9.80]) compared with controls after iodinated contrast media exposure. In the subgroup analysis, the risks of hyperthyroidism and hypothyroidism in cases compared with controls were 5.77 [CI 2.64-12.62] and 4.95 [CI 2.15-11.40] respectively. Half of the euthyroid nodular goiter cases developed thyroid dysfunction within one year after iodinated contrast media exposure. Interestingly, all thyroid-related comorbidities and drug prescriptions did not increase the risk of thyroid dysfunction. Presence of euthyroid nodular goiter was associated with higher risk of thyroid dysfunction including hyperthyroidism and hypothyroidism after iodinated contrast media exposure.
Model-Selection Theory: The Need for a More Nuanced Picture of Use-Novelty and Double-Counting
Steele, Katie; Werndl, Charlotte
2018-01-01
Abstract This article argues that common intuitions regarding (a) the specialness of ‘use-novel’ data for confirmation and (b) that this specialness implies the ‘no-double-counting rule’, which says that data used in ‘constructing’ (calibrating) a model cannot also play a role in confirming the model’s predictions, are too crude. The intuitions in question are pertinent in all the sciences, but we appeal to a climate science case study to illustrate what is at stake. Our strategy is to analyse the intuitive claims in light of prominent accounts of confirmation of model predictions. We show that on the Bayesian account of confirmation, and also on the standard classical hypothesis-testing account, claims (a) and (b) are not generally true; but for some select cases, it is possible to distinguish data used for calibration from use-novel data, where only the latter confirm. The more specialized classical model-selection methods, on the other hand, uphold a nuanced version of claim (a), but this comes apart from (b), which must be rejected in favour of a more refined account of the relationship between calibration and confirmation. Thus, depending on the framework of confirmation, either the scope or the simplicity of the intuitive position must be revised. 1 Introduction2 A Climate Case Study3 The Bayesian Method vis-à-vis Intuitions4 Classical Tests vis-à-vis Intuitions5 Classical Model-Selection Methods vis-à-vis Intuitions 5.1 Introducing classical model-selection methods 5.2 Two cases6 Re-examining Our Case Study7 Conclusion PMID:29780170
Model-Selection Theory: The Need for a More Nuanced Picture of Use-Novelty and Double-Counting.
Steele, Katie; Werndl, Charlotte
2018-06-01
This article argues that common intuitions regarding (a) the specialness of 'use-novel' data for confirmation and (b) that this specialness implies the 'no-double-counting rule', which says that data used in 'constructing' (calibrating) a model cannot also play a role in confirming the model's predictions, are too crude. The intuitions in question are pertinent in all the sciences, but we appeal to a climate science case study to illustrate what is at stake. Our strategy is to analyse the intuitive claims in light of prominent accounts of confirmation of model predictions. We show that on the Bayesian account of confirmation, and also on the standard classical hypothesis-testing account, claims (a) and (b) are not generally true; but for some select cases, it is possible to distinguish data used for calibration from use-novel data, where only the latter confirm. The more specialized classical model-selection methods, on the other hand, uphold a nuanced version of claim (a), but this comes apart from (b), which must be rejected in favour of a more refined account of the relationship between calibration and confirmation. Thus, depending on the framework of confirmation, either the scope or the simplicity of the intuitive position must be revised. 1 Introduction 2 A Climate Case Study 3 The Bayesian Method vis-à-vis Intuitions 4 Classical Tests vis-à-vis Intuitions 5 Classical Model-Selection Methods vis-à-vis Intuitions 5.1 Introducing classical model-selection methods 5.2 Two cases 6 Re-examining Our Case Study 7 Conclusion .
NASA Astrophysics Data System (ADS)
Chen, Jie; Brissette, François P.; Lucas-Picher, Philippe
2016-11-01
Given the ever increasing number of climate change simulations being carried out, it has become impractical to use all of them to cover the uncertainty of climate change impacts. Various methods have been proposed to optimally select subsets of a large ensemble of climate simulations for impact studies. However, the behaviour of optimally-selected subsets of climate simulations for climate change impacts is unknown, since the transfer process from climate projections to the impact study world is usually highly non-linear. Consequently, this study investigates the transferability of optimally-selected subsets of climate simulations in the case of hydrological impacts. Two different methods were used for the optimal selection of subsets of climate scenarios, and both were found to be capable of adequately representing the spread of selected climate model variables contained in the original large ensemble. However, in both cases, the optimal subsets had limited transferability to hydrological impacts. To capture a similar variability in the impact model world, many more simulations have to be used than those that are needed to simply cover variability from the climate model variables' perspective. Overall, both optimal subset selection methods were better than random selection when small subsets were selected from a large ensemble for impact studies. However, as the number of selected simulations increased, random selection often performed better than the two optimal methods. To ensure adequate uncertainty coverage, the results of this study imply that selecting as many climate change simulations as possible is the best avenue. Where this was not possible, the two optimal methods were found to perform adequately.
Arsenic Removal from Drinking Water - Web cast
Web cast presentation covered six topics: (1) Arsenic Chemistry, (2) Technology Selection/Arsenic Demonstration Program, (3) Case Study 1, (4) Caser Study 2, (5) Case Study 3, and (6) Media Regeneration Project. The presentation was considered a training session and consist of m...
Arsenic Removal from Drinking Water - Web Cast Presentation
Web cast presentation covered six topics: 1), Arsenic Chemistry, 2), Technology Selection/Arsenic Demonstration Program, 3), Case Study 1, 4), Caser Study 2, 5), Case Study 3, and 6), Media Regeneration Project. The presentation was considered a training session and consist of m...
USDA-ARS?s Scientific Manuscript database
Marker assisted selection (MAS) has become widely used in perennial crop breeding programs to accelerate and enhance cultivar development via selection during the juvenile phase and parental selection prior to crossing. Next generation sequencing (NGS) has been widely used for whole genome molecular...
USDA-ARS?s Scientific Manuscript database
Marker assisted selection (MAS) is often employed in crop breeding programs to accelerate and enhance cultivar development, via selection during the juvenile phase and parental selection prior to crossing. Next generation sequencing (NGS) and its derivative technologies have been used for genome-wid...
Microbial Resistance to Triclosan: A Case Study in Natural Selection
ERIC Educational Resources Information Center
Serafini, Amanda; Matthews, Dorothy M.
2009-01-01
Natural selection is the mechanism of evolution caused by the environmental selection of organisms most fit to reproduce, sometimes explained as "survival of the fittest." An example of evolution by natural selection is the development of bacteria that are resistant to antimicrobial agents as a result of exposure to these agents. Triclosan, which…
Thomas, Minta; De Brabanter, Kris; De Moor, Bart
2014-05-10
DNA microarrays are potentially powerful technology for improving diagnostic classification, treatment selection, and prognostic assessment. The use of this technology to predict cancer outcome has a history of almost a decade. Disease class predictors can be designed for known disease cases and provide diagnostic confirmation or clarify abnormal cases. The main input to this class predictors are high dimensional data with many variables and few observations. Dimensionality reduction of these features set significantly speeds up the prediction task. Feature selection and feature transformation methods are well known preprocessing steps in the field of bioinformatics. Several prediction tools are available based on these techniques. Studies show that a well tuned Kernel PCA (KPCA) is an efficient preprocessing step for dimensionality reduction, but the available bandwidth selection method for KPCA was computationally expensive. In this paper, we propose a new data-driven bandwidth selection criterion for KPCA, which is related to least squares cross-validation for kernel density estimation. We propose a new prediction model with a well tuned KPCA and Least Squares Support Vector Machine (LS-SVM). We estimate the accuracy of the newly proposed model based on 9 case studies. Then, we compare its performances (in terms of test set Area Under the ROC Curve (AUC) and computational time) with other well known techniques such as whole data set + LS-SVM, PCA + LS-SVM, t-test + LS-SVM, Prediction Analysis of Microarrays (PAM) and Least Absolute Shrinkage and Selection Operator (Lasso). Finally, we assess the performance of the proposed strategy with an existing KPCA parameter tuning algorithm by means of two additional case studies. We propose, evaluate, and compare several mathematical/statistical techniques, which apply feature transformation/selection for subsequent classification, and consider its application in medical diagnostics. Both feature selection and feature transformation perform well on classification tasks. Due to the dynamic selection property of feature selection, it is hard to define significant features for the classifier, which predicts classes of future samples. Moreover, the proposed strategy enjoys a distinctive advantage with its relatively lesser time complexity.
ERIC Educational Resources Information Center
Nielsen, Richard A.
2016-01-01
This article shows how statistical matching methods can be used to select "most similar" cases for qualitative analysis. I first offer a methodological justification for research designs based on selecting most similar cases. I then discuss the applicability of existing matching methods to the task of selecting most similar cases and…
Laland, Kevin N
2008-11-12
Genes and culture represent two streams of inheritance that for millions of years have flowed down the generations and interacted. Genetic propensities, expressed throughout development, influence what cultural organisms learn. Culturally transmitted information, expressed in behaviour and artefacts, spreads through populations, modifying selection acting back on populations. Drawing on three case studies, I will illustrate how this gene-culture coevolution has played a critical role in human evolution. These studies explore (i) the evolution of handedness, (ii) sexual selection with a culturally transmitted mating preference, and (iii) cultural niche construction and human evolution. These analyses shed light on how genes and culture shape each other, and on the significance of feedback mechanisms between biological and cultural processes.
Traffic operational evaluation of traffic impact analysis (TIA) case sites.
DOT National Transportation Integrated Search
2010-09-22
This report summarizes traffic operational evaluation of six select traffic impact analysis (TIA) case sites and the effectiveness of forecasting methods used in TIA studies. Six TIA case sites comprising 15 signalized intersections and 2 unsignalize...
Case reports and case series in prehospital emergency care research.
Patterson, P Daniel; Weaver, Matthew; Clark, Sunday; Yealy, Donald M
2010-11-01
Research begins with a clearly stated question, problem or hypothesis. The selection of a study design appropriate to the task is the next key step. This paper provides guidance for the use of case report and case series designs by describing the 'what', 'when' and 'how' of both designs. Also described is the use of case reports and case series study designs in prehospital emergency research and the quality of published literature from 2000 to mid-2008.
ERIC Educational Resources Information Center
Low, Ee Ling; Hui, Chenri; Cai, Li
2017-01-01
This paper explores how thinking and values in student teachers are cultivated in the Singapore context, via a case study of a teacher educator selected based on having won excellence in teaching commendation awards. The study adopts a qualitative case study methodology (i.e., interviews with the teacher educator and her student teachers) and uses…
Thomas Midgley, Jr., and the Development of New Substances: A Case Study for Chemical Educators
ERIC Educational Resources Information Center
Viana, Hélio Elael Bonini; Porto, Paulo Alves
2013-01-01
This paper presents a history of chemistry case study focusing on selected aspects of the work of American engineer Thomas Midgley, Jr. (1889-1944): the development of tetraethyl lead as an antiknock gasoline additive and of chlorofluorocarbons (CFCs) as fluids for refrigeration devices. One general aim of this case study is to display the complex…
Walshe, Catherine
2011-12-01
Complex, incrementally changing, context dependent and variable palliative care services are difficult to evaluate. Case study research strategies may have potential to contribute to evaluating such complex interventions, and to develop this field of evaluation research. This paper explores definitions of case study (as a unit of study, a process, and a product) and examines the features of case study research strategies which are thought to confer benefits for the evaluation of complex interventions in palliative care settings. Ten features of case study that are thought to be beneficial in evaluating complex interventions in palliative care are discussed, drawing from exemplars of research in this field. Important features are related to a longitudinal approach, triangulation, purposive instance selection, comprehensive approach, multiple data sources, flexibility, concurrent data collection and analysis, search for proving-disproving evidence, pattern matching techniques and an engaging narrative. The limitations of case study approaches are discussed including the potential for subjectivity and their complex, time consuming and potentially expensive nature. Case study research strategies have great potential in evaluating complex interventions in palliative care settings. Three key features need to be exploited to develop this field: case selection, longitudinal designs, and the use of rival hypotheses. In particular, case study should be used in situations where there is interplay and interdependency between the intervention and its context, such that it is difficult to define or find relevant comparisons.
Crescent Evaluation : appendix B : state case study evaluation report
DOT National Transportation Integrated Search
1994-02-01
The state case study evaluation approach uniquely captured an understanding of the potential of such a system by documenting the experiences, issues, and opportunities of selected key state government personnel from a cross-section of involved agenci...
Study on Quality of IUD Services Provided by Trained Professionals at Teaching Institutes.
Prasad, Noopur; Jain, M L; Meena, B S
2018-06-01
Access the completeness in IUD services provided by trained professionals and find out the weak links. Study was conducted on 100 IUD trained professionals of tertiary care hospital and nursing teaching institute. All were given questionnaire that was duly filled by them. Data obtained were analysed. Protocols of case selection, pre-insertion counselling, insertion process and follow-up were assessed. All the four criteria were assessed on score of ten. Study group could not get ten points under any of the set criteria. Average of 53% case selection, 31.4% pre-insertion counselling, 42.5% insertion protocols and 46.1% follow-up counselling criteria were observed by study group. Highest compliance of protocols was seen among postgraduate students. Although IUD training is given to all medical professionals and IUD facility is available up to subcentres but the study shows that completeness in services is still lacking. Ensuring ideal place for IUD insertion, proper case selection, use of specific instruments for insertion and observance of insertion protocols are very vital for the success of IUD.
Development of a Rubber-Based Product Using a Mixture Experiment: A Challenging Case Study
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kaya, Yahya; Piepel, Gregory F.; Caniyilmaz, Erdal
2013-07-01
Many products used in daily life are made by blending two or more components. The properties of such products typically depend on the relative proportions of the components. Experimental design, modeling, and data analysis methods for mixture experiments provide for efficiently determining the component proportions that will yield a product with desired properties. This article presents a case study of the work performed to develop a new rubber formulation for an o-ring (a circular gasket) with requirements specified on 10 product properties. Each step of the study is discussed, including: 1) identifying the objective of the study and requirements formore » properties of the o-ring, 2) selecting the components to vary and specifying the component constraints, 3) constructing a mixture experiment design, 4) measuring the responses and assessing the data, 5) developing property-composition models, 6) selecting the new product formulation, and 7) confirming the selected formulation in manufacturing. The case study includes some challenging and new aspects, which are discussed in the article.« less
State Politics and Education: An Examination of Selected Multiple-State Case Studies.
ERIC Educational Resources Information Center
Burlingame, Martin; Geske, Terry G.
1979-01-01
Reviews the multiple-state case study literature, highlights some findings, discusses several methodological issues, and concludes with suggestions for possible research agendas. Urges students and researchers to be more actively critical of the assumptions and findings of these studies. (Author/IRT)
Selective scene perception deficits in a case of topographical disorientation.
Robin, Jessica; Lowe, Matthew X; Pishdadian, Sara; Rivest, Josée; Cant, Jonathan S; Moscovitch, Morris
2017-07-01
Topographical disorientation (TD) is a neuropsychological condition characterized by an inability to find one's way, even in familiar environments. One common contributing cause of TD is landmark agnosia, a visual recognition impairment specific to scenes and landmarks. Although many cases of TD with landmark agnosia have been documented, little is known about the perceptual mechanisms which lead to selective deficits in recognizing scenes. In the present study, we test LH, a man who exhibits TD and landmark agnosia, on measures of scene perception that require selectively attending to either the configural or surface properties of a scene. Compared to healthy controls, LH demonstrates perceptual impairments when attending to the configuration of a scene, but not when attending to its surface properties, such as the pattern of the walls or whether the ground is sand or grass. In contrast, when focusing on objects instead of scenes, LH demonstrates intact perception of both geometric and surface properties. This study demonstrates that in a case of TD and landmark agnosia, the perceptual impairments are selective to the layout of scenes, providing insight into the mechanism of landmark agnosia and scene-selective perceptual processes. Copyright © 2017 Elsevier Ltd. All rights reserved.
Uzorka, J W; Arend, S M
2017-07-01
While postnatal toxoplasmosis in immune-competent patients is generally considered a self-limiting and mild illness, it has been associated with a variety of more severe clinical manifestations. The causal relation with some manifestations, e.g. myocarditis, has been microbiologically proven, but this is not unequivocally so for other reported associations, such as with epilepsy. We aimed to systematically assess causality between postnatal toxoplasmosis and epilepsy in immune-competent patients. A literature search was performed. The Bradford Hill criteria for causality were used to score selected articles for each component of causality. Using an arbitrary but defined scoring system, the maximal score was 15 points (13 for case reports). Of 704 articles, five case reports or series and five case-control studies were selected. The strongest evidence for a causal relation was provided by two case reports and one case-control study, with a maximal causality score of, respectively, 9/13, 10/13 and 10/15. The remaining studies had a median causality score of 7 (range 5-9). No selection bias was identified, but 6/10 studies contained potential confounders (it was unsure whether the infection was pre- or postnatal acquired, or immunodeficiency was not specifically excluded). Based on the evaluation of the available literature, although scanty and of limited quality, a causal relationship between postnatal toxoplasmosis and epilepsy seems possible. More definite proof requires further research, e.g. by performing Toxoplasma serology in all de novo epilepsy cases.
Cavity trees, snags, and selection cutting: a northern hardwood case study
Laura S. Kenefic; Ralph D. Nyland
2007-01-01
Although traditional application of the selection system includes a focus on high-value trees that may reduce cavities and snags, few studies have quantified those habitat features in managed uneven-aged stands. We examined the effects of single-tree selection cutting on cavity trees and snags in a northern hardwood stand immediately prior to the second cutting....
ERIC Educational Resources Information Center
Price, Jay R.
This study sought information about selective service rejection in Delaware, specifically rejectee characteristics, reasons for rejection, and the high rejection rate in Delaware. The basic design was a modified case study method in which a sample of individual records were examined. Differences between this sample and national samples were tested…
Barterian, Justin A; Sanchez, Joel M; Magen, Jed; Siroky, Allison K; Mash, Brittany L; Carlson, John S
2018-01-01
This study examined the utility of fluoxetine in the treatment of 5 children, aged 5 to 14 years, diagnosed with selective mutism who also demonstrated symptoms of social anxiety. A nonconcurrent, randomized, multiple-baseline, single-case design with a single-blind placebo-controlled procedure was used. Parents and the study psychiatrist completed multiple methods of assessment including Direct Behavior Ratings and questionnaires. Treatment outcomes were evaluated by calculating effect sizes for each participant as an individual and for the participants as a group. Information regarding adverse effects with an emphasis on behavioral disinhibition and ratings of parental acceptance of the intervention was gathered. All 5 children experienced improvement in social anxiety, responsive speech, and spontaneous speech with medium to large effect sizes; however, children still met criteria for selective mutism at the end of the study. Adverse events were minimal, with only 2 children experiencing brief occurrences of minor behavioral disinhibition. Parents found the treatment highly acceptable.
Sørensen, Holger J; Larsen, Janne T; Mors, Ole; Nordentoft, Merete; Mortensen, Preben B; Petersen, Liselotte
2015-03-01
Different case definitions of schizophrenia have been used in register based research. However, no previous study has externally validated two different case definitions of schizophrenia against a wide range of risk factors for schizophrenia. We investigated hazard ratios (HRs) for a wide range of risk factors for ICD-10 DCR schizophrenia using a nationwide Danish sample of 2,772,144 residents born in 1955-1997. We compared one contact only (OCO) (the case definition of schizophrenia used in Danish register based studies) with two or more contacts (TMC) (a case definition of at least 2 inpatient contacts with schizophrenia). During the follow-up, the OCO definition included 15,074 and the TMC 7562 cases; i.e. half as many. The TMC case definition appeared to select for a worse illness course. A wide range of risk factors were uniformly associated with both case definitions and only slightly higher risk estimates were found for the TMC definition. Choosing at least 2 inpatient contacts with schizophrenia (TMC) instead of the currently used case definition would result in almost similar risk estimates for many well-established risk factors. However, this would also introduce selection and include considerably fewer cases and reduce power of e.g. genetic studies based on register-diagnosed cases only. Copyright © 2015 Elsevier B.V. All rights reserved.
Bentley, R Alexander
2008-08-27
The evolution of vocabulary in academic publishing is characterized via keyword frequencies recorded in the ISI Web of Science citations database. In four distinct case-studies, evolutionary analysis of keyword frequency change through time is compared to a model of random copying used as the null hypothesis, such that selection may be identified against it. The case studies from the physical sciences indicate greater selection in keyword choice than in the social sciences. Similar evolutionary analyses can be applied to a wide range of phenomena; wherever the popularity of multiple items through time has been recorded, as with web searches, or sales of popular music and books, for example.
Random Drift versus Selection in Academic Vocabulary: An Evolutionary Analysis of Published Keywords
Bentley, R. Alexander
2008-01-01
The evolution of vocabulary in academic publishing is characterized via keyword frequencies recorded in the ISI Web of Science citations database. In four distinct case-studies, evolutionary analysis of keyword frequency change through time is compared to a model of random copying used as the null hypothesis, such that selection may be identified against it. The case studies from the physical sciences indicate greater selection in keyword choice than in the social sciences. Similar evolutionary analyses can be applied to a wide range of phenomena; wherever the popularity of multiple items through time has been recorded, as with web searches, or sales of popular music and books, for example. PMID:18728786
Access Management Awareness Program. Phase II Report
DOT National Transportation Integrated Search
1997-01-01
This report presents the results of a number of detailed Iowa access management case studies. Case studies were selected to provide a cross-section of locations and community sizes in Iowa as well as a variety of project types. Projects were analyzed...
Selective Mutism in Elementary School: Multidisciplinary Interventions.
ERIC Educational Resources Information Center
Giddan, Jane J.; And Others
1997-01-01
Presents the symptoms of selective mutism and historical background for treatment. It provides a case study which illustrates successful multidisciplinary treatment outcomes for a child who was selectively mute. Issues relevant to speech-language pathologists working with elementary school children are discussed and treatment guidelines provided.…
ERIC Educational Resources Information Center
Messa, Emily A.; Horn, Catherine L.; Longacre, Teri Elkins; Olenchak, F. Richard; Penney, Lisa M.
2016-01-01
A case study analyzed how supervisors at one university selected competencies, or trait-based skills, for non-faculty employees. This case study provides a valuable contribution by focusing on employees at one institution type--a large, public research university. While it has been documented that non-faculty employees provide important…
Violent Crime in Post-Civil War Guatemala: Causes and Policy Implications
2015-03-01
on field research and case studies in Honduras, Bolivia, and Argentina. Bailey’s Security Trap theory is comprehensive in nature and derived from... research question. The second phase uses empirical data and comparative case studies to validate or challenge selected arguments that potentially...Contextual relevancy, historical inference, Tools: Empirics and case conclusions empirical data studies Figme2. Sample Research Methodology E
Unequal Opportunities: The Recruitment, Selection and Promotion Prospects for Black Teachers.
ERIC Educational Resources Information Center
Brar, Harbhajan Singh
1991-01-01
The 1988 Education Reform Act greatly impacted equal opportunities in recruitment and selection of black teachers in the United Kingdom. A case study examines recruitment and selection in London, noting that ad hoc practices (encouraged by the 1988 Act) perpetuates the poor position of black teachers. (SM)
Film Selection in a Cinematherapy Intervention with Preadolescents Experiencing Parental Divorce
ERIC Educational Resources Information Center
Marsick, Emily
2010-01-01
Film selection and children's reactions to films are discussed in this article based on a qualitative multiple-case study with three preadolescent-aged children experiencing parental divorce. Six films were selected based on recommended films in cinematherapy. Although many films have been recommended for cinematherapy, multiple participants'…
Geospatial tools for data-sharing : case studies of select transportation agencies
DOT National Transportation Integrated Search
2014-09-01
This report provides case studies from 23 State Departments of Transportation (DOTs) and others that are developing, using, and maintaining a variety of geospatial applications and tools to support GDC goals. The report also summarizes the state of t...
US Interpretation of International Space Policies Regarding Commercial Resource Acquisitions
2015-06-12
examining research . These include narrative research , phenomenology , grounded theory , ethnography , and case studies . The first four of these......within a case study strategy a methodology of research must be selected. Possible choices in methods used include quantitative, qualitative , or mixed
A Framework for Reviewing EPA's State Administrative Cost Estimates: A Case Study (2007)
This report contains the findings of the set of case studies that look at EPA’s and the states’ information and methods used to estimate the costs to states charged with administering a selection of EPA regulations.
Comparative Studies in Special Education.
ERIC Educational Resources Information Center
Mazurek, Kas, Ed.; Winzer, Margret A., Ed.
This text presents 26 case studies which examine special education provisions for children in the world today. The reports focus on the current state of special education in selected nations and major issues and controversies in the field of special education within those nations. Each case study addresses the following themes: (1) prevalence of…
Katherine A. Zeller; Kevin McGarigal; Paul Beier; Samuel A. Cushman; T. Winston Vickers; Walter M. Boyce
2014-01-01
Estimating landscape resistance to animal movement is the foundation for connectivity modeling, and resource selection functions based on point data are commonly used to empirically estimate resistance. In this study, we used GPS data points acquired at 5-min intervals from radiocollared pumas in southern California to model context-dependent point selection...
ERIC Educational Resources Information Center
Claycomb, Gregory D.; Venable, Frances A.
2015-01-01
In an effort to broaden the selection of research opportunities available to a student registered in a one-semester, upper-level independent study course at a primarily undergraduate institution (PUI), a highly motivated student was asked to select, evaluate, and modify a standard operating procedure (SOP). The student gained valuable experience…
A Different World: African American, First Generation College Women at a Selective University
ERIC Educational Resources Information Center
Johnson, Jennifer Michelle
2013-01-01
The purpose of this study was to gain a better understanding of the academic and social experiences of African American, first generation college students attending a selective university. Following interpretive case study methodology, the major research questions guiding this study were: How do African American, first generation college students…
Secondary Mathematics Pre-Service Teachers' Processes of Selection and Integration of Technology
ERIC Educational Resources Information Center
Uzan, Erol
2017-01-01
This study investigated secondary mathematics pre-service teachers' (PSTs) knowledge of resources in terms of digital technologies, and explored the processes of both selection and integration of technology into their lesson plans. This study employed a case study design. Participants were six secondary mathematics PSTs who enrolled in a methods…
Sagara, Yoshiko; Kiyosue, Hiro; Tanoue, Shuichi; Shimada, Ryuichi; Hongo, Norio; Kohno, Tatsuyuki; Kawano, Kenji; Mori, Hiromu
2013-06-01
Comprehensive reports concerning selective embolization for arterial bleeding from third molar removal have not been published. We analyzed cases of arterial bleeding from third molar extraction that required transarterial embolization, and we demonstrate representative cases. Five consecutive patients (three men and two women, aged 24 to 37 years) who underwent transarterial embolization at our institution were included in this study. Four of them showed postoperative bleeding after lower third molar removal, and one suffered bleeding after upper third molar extraction. The period of time from extraction to embolization varied from 5 h to 5 weeks. Angiography revealed pseudoaneurysms at the inferior alveolar artery in four cases and at the superior alveolar artery in one case. The pseudoaneurysms were selectively embolized using 25-33 % n-butyl-2-cyanoacrylate (NBCA)-lipiodol. All of the cases showed good results angiographically and clinically. Transit hypoesthesia at the region of the mental nerve was observed in one patient. Selective transarterial embolization is an effective technique for arterial bleeding from third molar removal when it is difficult to obtain hemostasis by dental procedures. Injection of NBCA can be useful when the alveolar artery is too small to embolize with coils.
[Characteristics of case management programs and their potential for patient empowerment].
Grün, Oskar; Maier, Manfred
2008-01-01
Different types of case management programs have been increasingly developed for health care systems. This study, therefore, aimed to identify similarities and differences of case management programs, to estimate their shaping with special emphasis on patient empowerment, and to develop an instrument for their differentiation. During an interdisciplinary seminar for students, eight different case management programs were selected and analyzed. Five characteristics of case management programs were identified: type of case, extent of functions, players involved, limits of availability and need for resources. The programs were categorized into information-, provider-, disease- or patient centred. With these characteristics the selected programs could be exactly described and their potential for patient empowerment could be assessed. This newly developed tool for describing case management programs allows for their sufficient differentiation. The potential for patient empowerment apparently is most prominent in patient centred programs.
[Disciplinary verdicts in cases of child abuse; lessons for paediatricians].
Berkers, Gitte; Biesaart, Monique C I H; Leeuwenburgh-Pronk, Wendela G
2015-01-01
To give an overview of disciplinary cases regarding action taken by paediatricians and paediatric residents in cases of (suspected) child abuse and to discuss the considerations of the disciplinary board in these cases. Retrospective, descriptive study. We considered all disciplinary cases instigated from 2001 to 2013 against paediatricians or paediatric residents and selected complaints regarding action taken in cases of (suspected) child abuse. We divided these complaints into six categories and studied the considerations of the disciplinary board in these cases. From 33 disciplinary cases instigated from 2001 to 2013, we selected 76 complaints regarding action taken by paediatricians or paediatric residents in cases of (suspected) child abuse. The majority of these complaints concerned the reporting or requesting of information in the context of (suspected) child abuse. All of the complaints in the category 'unwarranted reporting of child abuse' were declared unfounded by the disciplinary judge. The disciplinary board declared all complaints unfounded in cases where the paediatrician or paediatric resident had followed the Dutch national protocol regarding reporting of child abuse and domestic violence. The disciplinary board examines whether action was taken in accordance with reasonable standards of professional competence and considers that paediatricians have an important role in identifying child abuse.
The problem of resonance in technology usage
NASA Technical Reports Server (NTRS)
Sayani, H. H.; Svoboda, C. P.
1981-01-01
Various information system tools and techniques are analyzed. A case study is presented which draws together the issues raised in three distinct cases. This case study shows a typical progression from the selection of an analysis methodology, to the adoption of an automated tool for specification and documentation, and the difficulty of fitting these into an existing life cycle development methodology.
Liu, Ying; Song, Shaoxia; Wang, Wei; Geng, Xingyi; Liu, Wen; Han, Debiao; Liu, Ti; Wu, Julong; Li, Zhong; Wang, Xianjun; Bi, Zhenqiang
2015-12-01
To analyze the status of acute upper respiratory infection and influenza-like illness (ILI) among community residents in Jinan in 2015, and to make a understand of the patient's medical treatment behavior and influenza vaccination coverage status in 2014. Balloting method and convenient sampling method were used to launch a household survey. The residents who had been in Jinan for more than 3 months were selected, to investigate the residents' attack ratio of acute upper respiratory and influenza-like from Jan. 8 to Feb. 7, 2015. Totally, 1 300 persons from 410 families were involved in this survey which recovered 1 241 valid questionnaires with the efficiency of 95.5%. Based on the national age-urban demographic statistics in 2010, the attack rates of acute respiratory infections, influenza-like illness were estimated by the direct standardization method, and the influenza vaccination rates were also calculated in this study. χ(2)-test method was used to compare the different status of incidence and vaccination among residents with different features. The attack rate of acute upper respiratory infection and influenza-like illness in Jinan from January 8, 2015 to February 7, 2015 were 30.2% (375 cases), and 6.1% (76 cases), respectively, with a standardized rate of 29.1% and 5.4%. 5.3% (66 cases) of the residents have vaccinated with the influenza vaccine inoculation, with an adjusted rate of 3.8%. The attack rate difference of acute upper respiratory tract infections was statistically significant between each age group (χ(2)=17.121, P= 0.002). The 0-4 age group had a highest attack rate (45.4%) of acute respiratory infection, while the 15-24 age group got the lowest (26.5%). 38.9% (146 cases) of patients went for a treatment in hospital. Among them, 37.7% (55 cases) of them selected the county level hospitals for treatment, 37.7% (55 cases) selected the community level hospitals, and 24.6% (36 cases) selected the individual clinic. Significant differences of influenza-like illness attack rate between each age group were also found in this study (χ(2)=76.79, P<0.001). 0-4 age group had the highest attack rate (22.7%). 81.6% (62 cases) of the ILI sought treatment in the hospital, of which 53.2% (33 cases) selected county level hospital or above, and 33.9% (21 cases) selected community hospital, and 12.9% (8 cases) selected the individual clinic. The attack rate of acute upper respiratory infections among the residents of Jinan was high, whereas that of influenza-like illness was relatively low. 0-4 age group had a higher risk of ILI than other age groups. Most of the cases were likely to take the treatment in large hospitals. In general, the coverage rate of influenza vaccination was relatively low.
Image selection in static telepathology through the Internet.
Della Mea, V; Cataldi, P; Boi, S; Finato, N; Della Palma, P; Beltrami, C A
1998-01-01
A telepathology study was carried out to examine the differences occurring when the images were selected by an experienced pathologist, a junior pathologist and a first-year resident. One hundred and fifty-five consecutive frozen-section pathology cases were collected and sent for consultation to a remote experienced pathologist using multimedia email. Local diagnoses (as reported in the files of the Institute, not from the image selector) and remote diagnoses (based on the images) were compared with those performed on paraffin-embedded sections. Acquisition time and number of selected images were recorded for each case and used to compare the different behaviour of the three local pathologists. Of the 155 cases sent by telepathology, four were considered insufficient for a diagnosis by the remote pathologist and thus the diagnosis was postponed. In the remaining 151 cases, the overall diagnostic agreement between remote and definitive diagnosis was 96.7%. The results indicate that in the routine diagnostic work of a frozen-section service, an inexperienced pathologist can select images which are sufficiently informative for a remote diagnosis, in a sufficiently short time.
Partner Power: A Study of Two Distance Education Consortia
ERIC Educational Resources Information Center
Pidduck, Anne Banks; Carey, Tom
2006-01-01
This research reports findings from a study which explored the process and criteria of partner selection--how and why partners are chosen--for two distance education consortia. The researchers reviewed recent literature on partnerships and partner selection. Two Canada-wide distance education consortia were identified as large-scale case studies…
Measles deaths in Nepal: estimating the national case-fatality ratio.
Joshi, Anand B; Luman, Elizabeth T; Nandy, Robin; Subedi, Bal K; Liyanage, Jayantha B L; Wierzba, Thomas F
2009-06-01
To estimate the case-fatality ratio (CFR) for measles in Nepal, determine the role of risk factors, such as political instability, for measles mortality, and compare the use of a nationally representative sample of outbreaks versus routine surveillance or a localized study to establish the national CFR (nCFR). This was a retrospective study of measles cases and deaths in Nepal. Through two-stage random sampling, we selected 37 districts with selection probability proportional to the number of districts in each region, and then randomly selected within each district one outbreak among all those that had occurred between 1 March and 1 September 2004. Cases were identified by interviewing a member of each and every household and tracing contacts. Bivariate analyses were performed to assess the risk factors for a high CFR and determine the time from rash onset until death. Each factor's contribution to the CFR was determined through multivariate logistic regression. From the number of measles cases and deaths found in the study we calculated the total number of measles cases and deaths for all of Nepal during the study period and in 2004. We identified 4657 measles cases and 64 deaths in the study period and area. This yielded a total of about 82 000 cases and 900 deaths for all outbreaks in 2004 and a national CFR of 1.1% (95% confidence interval, CI: 0.5-2.3). CFR ranged from 0.1% in the eastern region to 3.4% in the mid-western region and was highest in politically insecure areas, in the Ganges plains and among cases < 5 years of age. Vitamin A treatment and measles immunization were protective. Most deaths occurred during the first week of illness. To our knowledge, this is the first CFR study based on a nationally representative sample of measles outbreaks. Routine surveillance and studies of a single outbreak may not yield an accurate nCFR. Increased fatalities associated with political insecurity are a challenge for health-care service delivery. The short period from disease onset to death and reduced mortality from treatment with vitamin A suggest the need for rapid, field-based treatment early in the outbreak.
Treating selective mutism using modular CBT for child anxiety: a case study.
Reuther, Erin T; Davis, Thompson E; Moree, Brittany N; Matson, Johnny L
2011-01-01
Selective mutism is a rare, debilitating condition usually seen in children. Unfortunately, there is little research examining effective treatments for this disorder, and designing an evidence-based treatment plan can be difficult. This case study presents the evidence-based treatment of an 8-year-old Caucasian boy with selective mutism using an established treatment for anxiety--Modular Cognitive-Behavioral Therapy for Childhood Anxiety Disorders (Chorpita, 2007). The treatment consisted of 21 sessions and included modules on psychoeducation, exposure, cognitive restructuring, social skills, and maintenance and relapse prevention. The client's symptoms were greatly improved by the end of treatment based on fear hierarchy ratings, self-report and parent-report questionnaires, and child and parent clinical interviews. In addition, at discharge the client no longer met criteria for selective mutism. Improvements were maintained when the client was reassessed at 1-month and 6-month follow-up appointments.
Efficient use of historical data for genomic selection: a case study of rust resistance in wheat
USDA-ARS?s Scientific Manuscript database
Genomic selection (GS) is a new methodology that can improve wheat breeding efficiency. To implement GS, a training population (TP) with both phenotypic and genotypic data is required to train a statistical model used to predict genotyped selection candidates (SCs). Several factors impact prediction...
ERIC Educational Resources Information Center
Whaley, Arthur L.; Clay, William A. L.; Broussard, Dominique
2017-01-01
The present study describes a culturally relevant approach to introductory psychology textbook selection for students attending a historically Black college/university (HBCU). The following multistage procedure was used: (1) a survey of HBCU psychology departments was conducted to ascertain how they selected their introductory psychology…
How To Select the Right Candidate for an Internship Program for Japanese Host Companies.
ERIC Educational Resources Information Center
Kumayama, Akihisa
The method used by the American Graduate School of International Management (AZ) to select participants for internships with Japanese companies is described and some case studies are offered as illustrations. The composition of the selection committee is noted, the interview process is discussed briefly (focusing on elicitation of student…
Overview of the Dissertation Process within the Framework of Flow Theory: A Qualitative Study
ERIC Educational Resources Information Center
Cakmak, Esra; Oztekin, Ozge; Isci, Sabiha; Danisman, Sahin; Uslu, Fatma; Karadag, Engin
2015-01-01
The purpose of this study is to examine the flow of doctoral students who are also research assistants and in the dissertation process. The study was designed using the case study method. The case undertaken in the study was the dissertation process. Eleven participants were selected into the study using maximum variation sampling. Face-to-face,…
Wagner, Abram L; Boulton, Matthew L; Gillespie, Brenda W; Zhang, Ying; Ding, Yaxing; Carlson, Bradley F; Luo, Xiaoyan; Montgomery, JoLynn P; Wang, Xiexiu
2017-01-01
Control groups in previous case-control studies of vaccine-preventable diseases have included people immune to disease. This study examines risk factors for measles acquisition among adults 20 to 49 years of age in Tianjin, China, and compares findings using measles IgG antibody-negative controls to all controls, both IgG-negative and IgG-positive. Measles cases were sampled from a disease registry, and controls were enrolled from community registries in Tianjin, China, 2011-2015. Through a best subsets selection procedure, we compared which variables were selected at different model sizes when using IgG-negative controls or all controls. We entered risk factors for measles in two separate logistic regression models: one with measles IgG-negative controls and the other with all controls. The study included 384 measles cases and 1,596 community controls (194 IgG-negative). Visiting a hospital was an important risk factor. For specialty hospitals, the odds ratio (OR) was 4.53 (95% confidence interval (CI): 1.28, 16.03) using IgG-negative controls, and OR = 5.27 (95% CI: 2.73, 10.18) using all controls. Variables, such as age or length of time in Tianjin, were differentially selected depending on the control group. Individuals living in Tianjin ≤3 years had 2.87 (95% CI: 1.46, 5.66) times greater odds of measles case status compared to all controls, but this relationship was not apparent for IgG-negative controls. We recommend that case-control studies examining risk factors for infectious diseases, particularly in the context of transmission dynamics, consider antibody-negative controls as the gold standard.
Academic Computing at Florida A&M University. A Case Study.
ERIC Educational Resources Information Center
Hunter, Beverly; Kearsley, Greg
This case study is one of a series on academic computing at minority institutions which is designed to assist educators at other such institutions in identifying academic computing needs, establishing realistic goals, organizing a staff, and selecting materials. Following a brief description of the purpose and background of the overall study, the…
Rethinking Workplace Learning in the Digital World: A Case Study of Open Badges
ERIC Educational Resources Information Center
Eaglen Bertrando, Sharen Linn
2017-01-01
The purpose of this collective case study was to explore digital badging in educational institutions as support for K-12 practitioners struggling to integrate technology into pedagogical practices. The researcher conducted a mixed-method study that captured perceptions about digital badges and follow-up interviews with selected badge users to…
The Effects of Policy Changes on the Educational Opportunity Centers: A Case Study
ERIC Educational Resources Information Center
Fountain-Ellis, Debra L.
2011-01-01
The purpose of this study is to explore the programmatic changes that occurred in the Educational Opportunity Centers (EOC) and how those changes influenced educational opportunities for adults. A case study design was used for this investigation. The directors of three EOCs were selected and interviewed for the study. These directors combined…
Boosting Reading Fluency: An Intervention Case Study at Subword Level
ERIC Educational Resources Information Center
Kairaluoma, Leila; Ahonen, Timo; Aro, Mikko; Holopainen, Leena
2007-01-01
This study is an intervention case study of fluency in Finnish-speaking children with dyslexia. Two 7-year-old children, a girl and a boy, were selected from the Jyvaskyla Longitudinal Study of Dyslexia. The intervention emphasised syllables as reading units, and proceeded from reading syllables to reading words and text. Letter knowledge, reading…
A Community of Congruence among Secondary Social Studies Teachers: A Case Study
ERIC Educational Resources Information Center
Province, Rachael
2012-01-01
The purpose of this case study was to explore the community of one purposely selected department of secondary social studies teachers. I aimed to provide insight into the nature of one community of congruence amid the many constraints and systemic pressures in school systems today. Many have suggested that education is a microcosm of larger…
Education and Work Councils: Four Case Studies.
ERIC Educational Resources Information Center
Prager, Audrey; And Others
This collection of four case studies represents the conclusion of a two-phase study of a federal program to sponsor education and work councils. Following an outline of the history and concept of education and work councils as well as the findings of a study of such councils, the importance of council collaboration with selected sectors is…
Selective Attention in Web Forms: An Exploratory Case Study with Older People
ERIC Educational Resources Information Center
Sayago, Sergio; Guijarro, Jose-Maria; Blat, Josep
2012-01-01
This article reports on an exploratory study aimed to identify which ways of marking required and optional fields help older people fill in web forms correctly. Drawing on a pilot study and selective attention research in ageing, modified versions of widely used forms were created, in which standard asterisks were replaced with one of three…
ERIC Educational Resources Information Center
St. John, Edward P.
As part of a study of selected developing colleges and universities funded in the Advanced Institutional Development Program (AIDP), this report focuses on St. Mary's Junior College (SMJC), a Roman Catholic, two-year college specializing exclusively in health, health-related and human service fields. The report considers SMJC's state of…
ERIC Educational Resources Information Center
Peltz, Mark R.
2013-01-01
This qualitative study focused on the experiences of eight male first-generation college students attending Kenmont College (pseudonym), a highly selective, residential liberal arts college located in the Midwestern United States. While first-generation college students have been studied in various contexts, very little is known about what…
ERIC Educational Resources Information Center
Padgett, Gary
2012-01-01
The purpose of this study was to describe and explain the portrayal of American Indians in U.S. textbooks selected for review in Hillsborough County, Florida's 2012 textbook adoption. The study identified which of the textbooks under consideration contained the greatest amount of information dedicated to American Indians. The study then analyzed…
Jury Selection in Child Sex Abuse Trials: A Case Analysis
ERIC Educational Resources Information Center
Cramer, Robert J.; Adams, Desiree D.; Brodsky, Stanley L.
2009-01-01
Child sex abuse cases have been the target of considerable psycho-legal research. The present paper offers an analysis of psychological constructs for jury selection in child sex abuse cases from the defense perspective. The authors specifically delineate general and case-specific jury selection variables. General variables include…
Kamiyama, S; Miyagi, H; Kanazawa, K
2000-01-01
To determine the therapeutic value of selective salpingography (SSG) for infertile women with patent fallopian tubes. Retrospective, case-control analysis. University Hospital, infertility clinic. Infertile cases with patent tubes documented by hysterosalpingography (HSG) or by HSG followed by laparoscopic examination (n = 80). Hysteroscopic SSG. Patency rate of tubes by SSG. Pregnancy rate following SSG. Eighty cases were divided into the study group (SSG performed, 37 cases) and the case-control group (SSG not performed, 43 cases). Successful SSG of at least one tube was obtained in all of 37 cases (100%) in whom SSG was attempted. A patency rate of 95.9% was documented in the 73 cannulated tubes of these cases. The total subsequent pregnancy rate (48.6%) within 12 months of follow-up after SSG was significantly higher than that (11.6%) obtained in the control group (p < 0.001). The cumulative pregnancy rate in the study group was also significantly higher than that in the control group (p < 0.001). The findings of the present study encourage the application of SSG to infertile women, either as a sole therapeutic approach or in association with other methods of assisted reproductive technology, even if their fallopian tubes are shown to be patent by HSG. Copyright 2000 S. Karger AG, Basel
Lesmerises, Rémi; St-Laurent, Martin-Hugues
2017-11-01
Habitat selection studies conducted at the population scale commonly aim to describe general patterns that could improve our understanding of the limiting factors in species-habitat relationships. Researchers often consider interindividual variation in selection patterns to control for its effects and avoid pseudoreplication by using mixed-effect models that include individuals as random factors. Here, we highlight common pitfalls and possible misinterpretations of this strategy by describing habitat selection of 21 black bears Ursus americanus. We used Bayesian mixed-effect models and compared results obtained when using random intercept (i.e., population level) versus calculating individual coefficients for each independent variable (i.e., individual level). We then related interindividual variability to individual characteristics (i.e., age, sex, reproductive status, body condition) in a multivariate analysis. The assumption of comparable behavior among individuals was verified only in 40% of the cases in our seasonal best models. Indeed, we found strong and opposite responses among sampled bears and individual coefficients were linked to individual characteristics. For some covariates, contrasted responses canceled each other out at the population level. In other cases, interindividual variability was concealed by the composition of our sample, with the majority of the bears (e.g., old individuals and bears in good physical condition) driving the population response (e.g., selection of young forest cuts). Our results stress the need to consider interindividual variability to avoid misinterpretation and uninformative results, especially for a flexible and opportunistic species. This study helps to identify some ecological drivers of interindividual variability in bear habitat selection patterns.
Curtis, S; Gesler, W; Smith, G; Washburn, S
2000-04-01
This paper focuses on the question of sampling (or selection of cases) in qualitative research. Although the literature includes some very useful discussions of qualitative sampling strategies, the question of sampling often seems to receive less attention in methodological discussion than questions of how data is collected or is analysed. Decisions about sampling are likely to be important in many qualitative studies (although it may not be an issue in some research). There are varying accounts of the principles applicable to sampling or case selection. Those who espouse 'theoretical sampling', based on a 'grounded theory' approach, are in some ways opposed to those who promote forms of 'purposive sampling' suitable for research informed by an existing body of social theory. Diversity also results from the many different methods for drawing purposive samples which are applicable to qualitative research. We explore the value of a framework suggested by Miles and Huberman [Miles, M., Huberman,, A., 1994. Qualitative Data Analysis, Sage, London.], to evaluate the sampling strategies employed in three examples of research by the authors. Our examples comprise three studies which respectively involve selection of: 'healing places'; rural places which incorporated national anti-malarial policies; young male interviewees, identified as either chronically ill or disabled. The examples are used to show how in these three studies the (sometimes conflicting) requirements of the different criteria were resolved, as well as the potential and constraints placed on the research by the selection decisions which were made. We also consider how far the criteria Miles and Huberman suggest seem helpful for planning 'sample' selection in qualitative research.
Rebel Integration in Conflict Settlements: Past Lessons and the Prospects of MILF Reintegration
2017-12-01
ethnicity, religion, or language among a nation’s citizens.33 A series of investigations on case studies conducted by Matthew Hoddie and Caroline Hartzell...rebel reintegration from previous peace agreements was consulted. The selected case studies center on the peace agreements in Zimbabwe, Rwanda...Dayton.” 85 Akyol. 86 David Wage and Lois Haigh, “A Case Study on the Arusha Peace Agreement” (Florida State University, July 19, 2004), http
Otologic manifestations of Larsen syndrome.
Marques, Letícia Helena de Sousa; Martins, Daniela Vieira; Juares, Gabriel Liria; Lorenzetti, Fábio Tadeu Moura; Monsanto, Rafael da Costa
2017-10-01
To describe and discuss otologic manifestations of Larsen syndrome, based on a case report and a systematic review of the literature. We performed a PubMED database search, and we selected studies reporting otolaryngologic manifestations secondary to Larsen syndrome. The selected articles were read in full, and three researchers independently extracted data from the studies. In parallel, we report the case of a 14-year-old patient who had hearing loss secondary to Larsen syndrome. Fifteen studies met our selection criteria. Seven studies reported hearing loss in patients with Larsen syndrome (4 had conductive hearing loss and 3 had mixed hearing loss). The conductive hearing loss may be secondary to ossicular malformations and/or middle ear effusions. Other causes for conductive hearing loss are mesenchymal remnants in the middle ear, Eustachian tube dysfunction, and cleft palate. Surgical management of the hearing loss is possible in selected cases, although the surgical and anesthetic risks should be considered. Hearing aids seem to be safe and effective treatment options for the hearing loss secondary to Larsen syndrome. Although rare, patients with Larsen syndrome may have hearing loss. The most frequent type of deficit is conductive, either secondary to malformation of the ossicles or middle ear effusion. Possible surgical correction of these abnormalities should be weighed against the anesthetic risks of these patients. Copyright © 2017 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Tahir, Mohamad Zamhari; Nawi, Mohd Nasrun Mohd; Ibrahim, Amlus
2016-08-01
This paper presents the findings of a case study to achieve energy-efficient performance of conventional office buildings in Malaysia. Two multi-storey office buildings in Federal Territory of Malaysia have been selected. The aim is to study building energy saving potential then to highlight the appropriate measures that can be implemented. Data was collected using benchmarking method by comparing the measured consumption to other similar office buildings and a series of preliminary audit which involves interviews, a brief review of utility and operating data as well as a walkthrough in the buildings. Additionally, in order to get a better understanding of major energy consumption in the selected buildings, general audit have been conducted to collect more detailed information about building operation. In the end, this study emphasized low-cost and no-cost practice to achieve energy efficiency with significant results in some cases.
EPA announced the availability of the final report, Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen. This report is a starting point to determine what is known and what needs to be known about selected nanomaterials as par...
A CROSS-SPECIES MODE OF ACTION INFORMATION ASSESSMENT: A CASE STUDY OF BISPHENOL A
A case study assessing the utility of this approach was performed for bisphenol A (BPA). BPA, a component of polycarbonate plastics, epoxy resins, and polyester resins, was selected because it is a high production volume chemical; data have been identified for both vertebrate an...
A Case Study of Learning Architecture and Reciprocity
ERIC Educational Resources Information Center
Smith, Anne B.
2009-01-01
This ethnographic case study follows the trajectory of one child's learning disposition, reciprocity, and its relationship to the "learning architecture" of her early childhood and primary school learning environments, over eighteen months. Learning dispositions are coping strategies or habits of mind, and tendencies to respond to and select from…
COMPARISON OF GEOCODING METHODS USED IN CASE-CONTROL STUDY OF AIR QUALITY AND BIRTH DEFECTS
Introduction: Accurate geocoding of maternal residence is critical to the success of an ongoing case-control study of exposure to five criteria air pollutants and the risk of selected birth defects in seven Texas counties between 1997 and 2000. The geocoded maternal residence a...
Relational Aggression and Burnout: Fight, Hide, or Run?
ERIC Educational Resources Information Center
Culver, Mary K.
2007-01-01
This study looks at female relational aggression in an effort to illustrate factors involved in selecting appropriate responses for the situation. This ethnographic case study analyzes a principal's interview, personal journal, and artifact file to describe the situations and reactions present in a severe case of female relational aggression.…
Student Perceptions of Public Accounting Internships: A Case Study
ERIC Educational Resources Information Center
Paine, Brenda E.
2017-01-01
The purpose of this dissertation research was to gather data about how students felt about their public accounting internships and to understand how their internship experiences affected their feelings toward public accounting and their career paths. One small, private, Midwest business college was selected for this case study research. Nine…
Xiao, Ying; Zhao, Yubin; Xie, Yanming
2011-10-01
The nested case-control study design (or the case-control in a cohort study) is described here as a new study design used in safe evaluation of post-marketing traditional Chinese medicine injection. In the nested case-control study, cases of a disease that occur in a defined cohort are identified and, for each, a specified number of matched controls is selected from among those in the cohort who have not developed the disease by the time of disease occurrence in the case. For many research questions, the nested case-control design potentially offers impressive reductions in costs and efforts of data collection and analysis compared with the full cohort approach, with relatively minor loss in statistical efficiency. The nested case-control design is particularly advantageous for studies in safe evaluation of post-marketing traditional Chinese medicine injection. Some examples of the application of nested case-control study were given.
Applying Bayesian Item Selection Approaches to Adaptive Tests Using Polytomous Items
ERIC Educational Resources Information Center
Penfield, Randall D.
2006-01-01
This study applied the maximum expected information (MEI) and the maximum posterior-weighted information (MPI) approaches of computer adaptive testing item selection to the case of a test using polytomous items following the partial credit model. The MEI and MPI approaches are described. A simulation study compared the efficiency of ability…
ERIC Educational Resources Information Center
White, James G.
2013-01-01
Scope and Method of Study: This naturalistic inquiry case study explored a selected pre-kindergarten program and the extent of its provision for school readiness through the lens of General Systems Theory. Assessment results from kindergarten students at three separate elementary schools were analyzed, interviews were completed with select early…
A population-based case-control study investigated the association between maternal exposure to criteria air pollutants, CO, NO2, O3, SO2, and PM10 during weeks three through eight of pregnancy, and the risk of selected cardiac birth defects and oral clefts among live births and ...
Economic feasibility of solar thermal industrial applications and selected case studies
NASA Astrophysics Data System (ADS)
Montelione, A.; Boyd, D.; Branz, M.
1981-12-01
The economic feasibility is assessed of utilizing solar energy to augment an existing fossil fuel system to generate industrial process heat. Several case studies in the textile and food processing industries in the southern United States were analyzed. Sensitivity analyses were performed, and comparisons illustrating the effects of the Economic Recovery Tax Act of 1981 were made. The economic desirability of the proposed solar systems varied with the type of system selected, location of the facility, state tax credits, and type of fuel displaced. For those systems presently not economical, the projected time to economic feasibility was ascertained.
User-friendly tools on handheld devices for observer performance study
NASA Astrophysics Data System (ADS)
Matsumoto, Takuya; Hara, Takeshi; Shiraishi, Junji; Fukuoka, Daisuke; Abe, Hiroyuki; Matsusako, Masaki; Yamada, Akira; Zhou, Xiangrong; Fujita, Hiroshi
2012-02-01
ROC studies require complex procedures to select cases from many data samples, and to set confidence levels in each selected case to generate ROC curves. In some observer performance studies, researchers have to develop software with specific graphical user interface (GUI) to obtain confidence levels from readers. Because ROC studies could be designed for various clinical situations, it is difficult task for preparing software corresponding to every ROC studies. In this work, we have developed software for recording confidence levels during observer studies on tiny personal handheld devices such as iPhone, iPod touch, and iPad. To confirm the functions of our software, three radiologists performed observer studies to detect lung nodules by using public database of chest radiograms published by Japan Society of Radiological Technology. The output in text format conformed to the format for the famous ROC kit from the University of Chicago. Times required for the reading each case was recorded very precisely.
[The protective efficacy of BCG against leprosy in São Paulo, Brazil].
Lombardi, C; Pedrazzani, E S; Pedrazzani, J C; Ferreira Filho, P; Zicker, F
1995-11-01
The protection against leprosy conferred by BCG vaccination was evaluated in a case-control study. Selected for the study were 97 patients under 16 years of age who had been diagnosed with leprosy (cases) and 385 healthy persons (controls), who were matched according to sex, age, place of residence, and type of contact (intra- or extradomicilliary). The cases were selected from a register of active cases as well as a series of new leprosy patients treated in 50 centers in the city of São Paulo, Brasil. To estimate the protective effect of BCG, the prevalences of BCG scars among cases and controls were compared. The presence of one or more scars was associated with a protective efficacy of 90% (95% confidence interval: 78%-96%). Stratified analysis by age group, sex, socioeconomic level, and clinical form of leprosy did not reveal any important differences in the protection conferred by the vaccine. The significance of these findings and the appropriateness of using BCG in leprosy control programs is discussed.
Admiral Furman Academy: A Case Study in Selected Not-for-Profit Auditing Issues
ERIC Educational Resources Information Center
Grippo, Frank J.; Nassiripour, Sia
2009-01-01
The purpose of this case is to help students explore accounting and auditing issues often confronted by auditors of not-for-profit organizations. Given final financial statements, the goal of the case is to require students to prepare the footnotes that would be considered an integral part of the financial statements. The case is intended for…
ERIC Educational Resources Information Center
Värk, Aare; Reino, Anne
2018-01-01
This article reports the outcomes of a phenomenographical study of case managers' conceptions of case management work and its influence on the process and performance of the work of counselling the unemployed. A heterogeneous sample of 11 Estonian case managers was selected for in-depth interviews. Analysis of the interviews revealed three…
2010-01-01
Background Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. Methods We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. Results We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. Conclusion A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (Ptrend = 0.004). PMID:20920174
Campa, Daniele; Pardini, Barbara; Naccarati, Alessio; Vodickova, Ludmila; Novotny, Jan; Steinke, Verena; Rahner, Nils; Holinski-Feder, Elke; Morak, Monika; Schackert, Hans K; Görgens, Heike; Kötting, Judith; Betz, Beate; Kloor, Matthias; Engel, Christoph; Büttner, Reinhard; Propping, Peter; Försti, Asta; Hemminki, Kari; Barale, Roberto; Vodicka, Pavel; Canzian, Federico
2010-09-28
Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (Ptrend = 0.004).
O'Malley, A James; Cotterill, Philip; Schermerhorn, Marc L; Landon, Bruce E
2011-12-01
When 2 treatment approaches are available, there are likely to be unmeasured confounders that influence choice of procedure, which complicates estimation of the causal effect of treatment on outcomes using observational data. To estimate the effect of endovascular (endo) versus open surgical (open) repair, including possible modification by institutional volume, on survival after treatment for abdominal aortic aneurysm, accounting for observed and unobserved confounding variables. Observational study of data from the Medicare program using a joint model of treatment selection and survival given treatment to estimate the effects of type of surgery and institutional volume on survival. We studied 61,414 eligible repairs of intact abdominal aortic aneurysms during 2001 to 2004. The outcome, perioperative death, is defined as in-hospital death or death within 30 days of operation. The key predictors are use of endo, transformed endo and open volume, and endo-volume interactions. There is strong evidence of nonrandom selection of treatment with potential confounding variables including institutional volume and procedure date, variables not typically adjusted for in clinical trials. The best fitting model included heterogeneous transformations of endo volume for endo cases and open volume for open cases as predictors. Consistent with our hypothesis, accounting for unmeasured selection reduced the mortality benefit of endo. The effect of endo versus open surgery varies nonlinearly with endo and open volume. Accounting for institutional experience and unmeasured selection enables better decision-making by physicians making treatment referrals, investigators evaluating treatments, and policy makers.
The Case for Arts Education as a Required Component of an Accounting Student?s College Education
ERIC Educational Resources Information Center
Mason, J. David; Stefoff, Rebecca Mason
2004-01-01
A recent study has highlighted the importance of student perceptions of the accounting profession and the resultant self-selection process. This self-selection process may result in students self-selecting into the accounting area who are deficient in the essential qualities for success in the modern accounting profession. Warnock (1996) reports…
Integrating Factors of Grit in School Culture: Case Studies of Two Freshman Academies
ERIC Educational Resources Information Center
Coates, Margaret Marie
2017-01-01
The purpose of this qualitative case study is to explore the cultural manifestation of grit in two freshman academy environments and describe factors of grit that support student success. This study used purposeful sampling to select sites and participants. Data were collected through: administration of Douglas' (1982) grid and group 24-question…
ERIC Educational Resources Information Center
Parisky, Alex
2015-01-01
The purpose of this qualitative case study was to better understand the implementation of educational technology in selected medical schools. This study utilized Rogers' Diffusion of Innovation theory to investigate the perspectives of educational technology leaders at four different medical schools in the United States. In the coming years,…
van Wieren-de Wijer, Diane B M A; Maitland-van der Zee, Anke-Hilse; de Boer, Anthonius; Stricker, Bruno H Ch; Kroon, Abraham A; de Leeuw, Peter W; Bozkurt, O; Klungel, Olaf H
2009-04-01
To describe the design, recruitment and baseline characteristics of participants in a community pharmacy based pharmacogenetic study of antihypertensive drug treatment. Participants enrolled from the population-based Pharmaco-Morbidity Record Linkage System. We designed a nested case-control study in which we will assess whether specific genetic polymorphisms modify the effect of antihypertensive drugs on the risk of myocardial infarction. In this study, cases (myocardial infarction) and controls were recruited through community pharmacies that participate in PHARMO. The PHARMO database comprises drug dispensing histories of about 2,000,000 subjects from a representative sample of Dutch community pharmacies linked to the national registrations of hospital discharges. In total we selected 31010 patients (2777 cases and 28233 controls) from the PHARMO database, of whom 15973 (1871 cases, 14102 controls) were approached through their community pharmacy. Overall response rate was 36.3% (n = 5791, 794 cases, 4997 controls), whereas 32.1% (n = 5126, 701 cases, 4425 controls) gave informed consent to genotype their DNA. As expected, several cardiovascular risk factors such as smoking, body mass index, hypercholesterolemia, and diabetes mellitus were more common in cases than in controls. Furthermore, cases more often used beta-blockers and calcium-antagonists, whereas controls more often used thiazide diuretics, ACE-inhibitors, and angiotensin-II receptor blockers. We have demonstrated that it is feasible to select patients from a coded database for a pharmacogenetic study and to approach them through community pharmacies, achieving reasonable response rates and without violating privacy rules.
Cost of Hospitalization for Foodborne Diarrhea: A Case Study from Vietnam.
Hoang, Van Minh; Tran, Tuan Anh; Ha, Anh Duc; Nguyen, Viet Hung
2015-11-01
Vietnam is undergoing a rapid social and economic developments resulting in speedy urbanization, changes in methods for animal production, food marketing systems, and food consumption habits. These changes will have major impacts on human exposures to food poisoning. The present case study aimed to estimate hospitalization costs of foodborne diarrhea cases in selected health facilities in Vietnam. This is a facility-based cost-of-illness study conducted in seven health facilities in Northern Vietnam. All suspect cases of foodborne diarrhea, as diagnosed by doctors, who admitted to the studied health facilities during June-August, 2013 were selected. Costs associated with hospitalization for foodborne diseases were estimated from societal perspective using retrospective approach. We included direct and indirect costs of hospitalization of foodborne diarrhea cases. During the study period, 87 foodborne diarrhea cases were included. On average, the costs per treatment episode and per hospitalization day for foodborne diarrhea case were US$ 106.9 and US$ 33.6 respectively. Indirect cost (costs of times to patient, their relatives due to the patient's illness) made up the largest share (51.3%). Direct medical costs accounted for 33.8%; direct non-medical costs (patient and their relatives) represented 14.9%. Cost levels and compositions varied by level of health facilities. More attentions should be paid on prevention, control of foodborne diarrhea cases in Vietnam. Ensuring safety of food depends on efforts of everyone involved in food chain continuum, from production, processing, and transport to consumption.
ERIC Educational Resources Information Center
Lorenz, Kelley M.
2013-01-01
This study examined the effects of a home-reading program on parent-teacher communication and on the ability of parents to select reading material for their children. In this qualitative case study, parents of 4th grade students participated in a reading homework program with their children. Using constructivist theories, the study's…
A Multiple Case Study of a Baldrige-Based Peer Review Process in an Urban School District
ERIC Educational Resources Information Center
Ray, Janet L.
2012-01-01
Distinct purposes were identified for this phenomenological multiple-case study. The first purpose of the study was to determine in what ways the BbPRP influenced (a) leadership, (b) strategic planning, and (c) process management among the five selected schools within AISD. The second purpose of this study was to examine administrators'…
ERIC Educational Resources Information Center
Hobbs, Alysia Jocelyn
2010-01-01
This study selected a purposeful sample of eight high performing southern California elementary schools which achieved API scores above 900 over a three year period. A review of instructional strategies for each study school during the improvement process and resource allocation patterns was determined. Case studies of each school include…
Socialism. Grade Ten, Unit Two, 10.2. Comprehensive Social Studies Curriculum for the Inner City.
ERIC Educational Resources Information Center
Malone, Helen
The socialism unit of the tenth grade level of the FICSS series (Focus on Inner City Social Studies -- see SO 008 271) explores a selected history of socialist thought and the theoretical model of socialism. Three case studies of socialism are explored: Great Britain, Sweden, and Israel. The case studies are designed to answer questions concerning…
ERIC Educational Resources Information Center
Kuo, Mike Chu-Hsun
A study investigated the current enterprise training system in Taiwan and proposed suitable training suggestions for manufacturing industry through a carefully designed case study. Literature review and field study were used to gather research data. Interviews were conducted at four large manufacturing companies during the period October 1990 to…
"Tell Me a Story": The Use of Narrative as a Learning Tool for Natural Selection
ERIC Educational Resources Information Center
Prins, Renate; Avraamidou, Lucy; Goedhart, Martin
2017-01-01
Grounded within literature pointing to the value of narrative in communicating scientific information, the purpose of this study was to examine the use of stories as a tool for teaching about natural selection in the context of school science. The study utilizes a mixed method, case study approach which focuses on the design, implementation, and…
["Addiction" to phenelzine - case report].
Antosik-Wójcińska, Anna Z; Bzinkowska, Dorota; Chojnacka, Magdalena; Swiecicki, Łukasz; Torbiński, Jarosław
2013-01-01
The use of non-selective monoamine oxidase inhibitors (IMAO) may be associated with the risk of addiction, which is confirmed by case studies published so far. Harmful use of antidepressants in patients with affective disorders and anxiety is not frequent, but due to the fact that in clinical practice can meet with this phenomenon, we present the case of a 30-year-old patient with a history of using phenelzine who presented a combination of symptoms that meet criteria for addiction. The current classification of ICD- 10 does not consist the diagnosis of dependence on antidepressants. In this case, the category F55.0: abuse of a substance which does not cause addiction, should be used. In the literature most often mentioned as a possible substances with addictive potential is a group of non-selective MAO, particularly tranylcypromine. The mechanism of non-selective MAO dependence may be associated with the similarity of their chemical structure to amphetamine (both amphetamine and IMAO are derivatives of phenylethylamine), although the mechanism of action is different. Furthermore, it was noted that there is a group of patients in whom treatment with IMAO is associated with greater risk of abuse of these substances. The study contains the characteristics of this group of patients.
Bae, Jong-Myon; Kim, Eun Hee
2016-03-01
Research on how the risk of gastric cancer increases with Epstein-Barr virus (EBV) infection is lacking. In a systematic review that investigated studies published until September 2014, the authors did not calculate the summary odds ratio (SOR) due to heterogeneity across studies. Therefore, we include here additional studies published until October 2015 and conduct a meta-analysis with meta-regression that controls for the heterogeneity among studies. Using the studies selected in the previously published systematic review, we formulated lists of references, cited articles, and related articles provided by PubMed. From the lists, only case-control studies that detected EBV in tissue samples were selected. In order to control for the heterogeneity among studies, subgroup analysis and meta-regression were performed. In the 33 case-control results with adjacent non-cancer tissue, the total number of test samples in the case and control groups was 5280 and 4962, respectively. In the 14 case-control results with normal tissue, the total number of test samples in case and control groups was 1393 and 945, respectively. Upon meta-regression, the type of control tissue was found to be a statistically significant variable with regard to heterogeneity. When the control tissue was normal tissue of healthy individuals, the SOR was 3.41 (95% CI, 1.78 to 6.51; I-squared, 65.5%). The results of the present study support the argument that EBV infection increases the risk of gastric cancer. In the future, age-matched and sex-matched case-control studies should be conducted.
Hong, B; Birnie, A
2016-01-15
To investigate the provision of adult dental extraction under general anaesthesia (DGA) at the Royal Cornwall Hospitals NHS Trust (RCHT)-- specifically adult single tooth DGA episodes in regards to numbers, demographics, justifications, and appropriateness regarding the use of resources. Data were collected retrospectively from the patient case notes and electronic records for the complete study cohort. This study included all episodes of adult single tooth DGA in all RCHT sites during 2014, except for mandibular third molar and impacted teeth. Each case was tested against the DGA case selection criteria empirically devised for this study. In 2014, 106 episodes of adult single tooth DGA were carried out in RCHT that met the inclusion criteria. Younger females from more socio-economically deprived areas of Cornwall were increasingly likely to have this procedure. Mental disorders were the most prevalent co-morbidity (21.7%) in this cohort. The vast majority of patients (93.4%) had previously tolerated dental treatment without the need for general anaesthesia (GA). Many referrals (46.2%) and listings (30.2%) specifically stated patient demand-driven reasons. None of the cohort had DGA due to failure of sedation. There were potentially 11 episodes that met the DGA case selection criteria. Patients waited for 126 days (median) from the referral date for an operation which took seven minutes (median) to complete. The majority (83%) of the cases were simple exodontia. Twenty patients (18.9%) had previous DGA. Potentially a considerable proportion of GA prescription appeared to be driven by patient demand rather than clinical need. This study poses a fundamental question--what drives the demand for DGA? National data collection and specific DGA case selection criteria are recommended.
Mathis, Michael R; Naughton, Norah N; Shanks, Amy M; Freundlich, Robert E; Pannucci, Christopher J; Chu, Yijia; Haus, Jason; Morris, Michelle; Kheterpal, Sachin
2013-12-01
Due to economic pressures and improvements in perioperative care, outpatient surgical procedures have become commonplace. However, risk factors for outpatient surgical morbidity and mortality remain unclear. There are no multicenter clinical data guiding patient selection for outpatient surgery. The authors hypothesize that specific risk factors increase the likelihood of day case-eligible surgical morbidity or mortality. The authors analyzed adults undergoing common day case-eligible surgical procedures by using the American College of Surgeons' National Surgical Quality Improvement Program database from 2005 to 2010. Common day case-eligible surgical procedures were identified as the most common outpatient surgical Current Procedural Terminology codes provided by Blue Cross Blue Shield of Michigan and Medicare publications. Study variables included anthropometric data and relevant medical comorbidities. The primary outcome was morbidity or mortality within 72 h. Intraoperative complications included adverse cardiovascular events; postoperative complications included surgical, anesthetic, and medical adverse events. Of 244,397 surgeries studied, 232 (0.1%) experienced early perioperative morbidity or mortality. Seven independent risk factors were identified while controlling for surgical complexity: overweight body mass index, obese body mass index, chronic obstructive pulmonary disease, history of transient ischemic attack/stroke, hypertension, previous cardiac surgical intervention, and prolonged operative time. The demonstrated low rate of perioperative morbidity and mortality confirms the safety of current day case-eligible surgeries. The authors obtained the first prospectively collected data identifying risk factors for morbidity and mortality with day case-eligible surgery. The results of the study provide new data to advance patient-selection processes for outpatient surgery.
Exchangeability in the case-crossover design
Mittleman, Murray A; Mostofsky, Elizabeth
2014-01-01
In cohort and case-control studies, confounding that arises as a result of differences in the distribution of determinants of the outcome between exposure groups leading to non-exchangeability are addressed by restriction, matching or with statistical models. In case-only studies, this issue is addressed by comparing each individual with his/herself. Although case-only designs use self-matching and only include individuals who develop the outcome of interest, issues of non-exchangeability are identical to those that arise in traditional case-control and cohort studies. In this review, we describe one type of case-only design, the case-crossover design, and discuss how the concept of exchangeability can be used to understand issues of confounding, carryover effects, period effects and selection bias in case-crossover studies. PMID:24756878
Epidemiology of acute promyelocytic leukemia.
Mele, A; Stazi, M A; Pulsoni, A; Visani, G; Monarca, B; Castelli, G; Rocchi, L; Avvisati, G; Mandelli, F
1995-01-01
The estimated incidence of acute promyelocytic leukemia (APL) is approximately 6 cases per 10 million people per year with no apparent differences between sexes. The age of APL cases is younger than that of other acute myeloid leukemias (AML). Spatial and temporal clusters of APL have been reported. These observations suggest a possible selective role for environmental and/or occupational factors in APL development. A multicenter case-control study was carried out on risk factors for acute leukemias and preleukemias. In this report data related to APL are selectively analyzed from the larger study to identify specific risk factors. The case-control study on 38 cases of APL showed a strong association with shoemaking (odds ration 6.3, 95% confidence interval 1.3-31.1). A moderate leukemogenic effect from living in houses built with tuff, a polous building material containing gamma-emitting radionuclides and having a high radon concentration, and from using hair dyes was also suggested. These data, together with the reported spatial and temporal clustering of APL, support the hypothesis of specific environmental and/or occupational risk factors for APL among other AML subtypes and indicate the need for additional ad hoc multicenter studies.
Davis, Chester L; Pierce, John R; Henderson, William; Spencer, C David; Tyler, Christine; Langberg, Robert; Swafford, Jennan; Felan, Gladys S; Kearns, Martha A; Booker, Brigitte
2007-04-01
The Office of the Medical Inspector of the Department of Veterans Affairs (VA) studied the reliability of data collected by the VA's National Surgical Quality Improvement Program (NSQIP). The study focused on case selection bias, accuracy of reports on patients who died, and interrater reliability measurements of patient risk variables and outcomes. Surgical data from a sample of 15 VA medical centers were analyzed. For case selection bias, reviewers applied NSQIP criteria to include or exclude 2,460 patients from the database, comparing their results with those of NSQIP staff. For accurate reporting of patients who died, reviewers compared Social Security numbers of 10,444 NSQIP records with those found in the VA Beneficiary Identification and Records Locator Subsystem, VA Patient Treatment Files, and Social Security Administration death files. For measurement of interrater reliability, reviewers reabstracted 59 variables in each of 550 patient medical records that also were recorded in the NSQIP database. On case selection bias, the reviewers agreed with NSQIP decisions on 2,418 (98%) of the 2,460 cases. Computer record matching identified 4 more deaths than the NSQIP total of 198, a difference of about 2%. For 52 of the categorical variables, agreement, uncorrected for chance, was 96%. For 48 of 52 categorical variables, kappas ranged from 0.61 to 1.0 (substantial to almost perfect agreement); none of the variables had kappas of less than 0.20 (slight to poor agreement). This sample of medical centers shows adherence to criteria in selecting cases for the NSQIP database, for reporting deaths, and for collecting patient risk variables.
Steel, Daniel; Gonnerman, Chad; O'Rourke, Michael
2017-06-01
This article examines the relevance of survey data of scientists' attitudes about science and values to case studies in philosophy of science. We describe two methodological challenges confronting such case studies: 1) small samples, and 2) potential for bias in selection, emphasis, and interpretation. Examples are given to illustrate that these challenges can arise for case studies in the science and values literature. We propose that these challenges can be mitigated through an approach in which case studies and survey methods are viewed as complementary, and use data from the Toolbox Dialogue Initiative to illustrate this claim. Copyright © 2017 Elsevier Ltd. All rights reserved.
DOT National Transportation Integrated Search
2002-11-01
The catalog documents the seismic performance of bridges and ancillary components in the presence of liquefaction-induced ground displacements. Data pertaining to seismological, geotechnical, and structural aspects of numerous case studies are presen...
Kheifets, Leeka; Crespi, Catherine M; Hooper, Chris; Oksuzyan, Sona; Cockburn, Myles; Ly, Thomas; Mezei, Gabor
2015-01-01
We conducted a large epidemiologic case-control study in California to examine the association between childhood cancer risk and distance from the home address at birth to the nearest high-voltage overhead transmission line as a replication of the study of Draper et al. in the United Kingdom. We present a detailed description of the study design, methods of case ascertainment, control selection, exposure assessment and data analysis plan. A total of 5788 childhood leukemia cases and 3308 childhood central nervous system cancer cases (included for comparison) and matched controls were available for analysis. Birth and diagnosis addresses of cases and birth addresses of controls were geocoded. Distance from the home to nearby overhead transmission lines was ascertained on the basis of the electric power companies’ geographic information system (GIS) databases, additional Google Earth aerial evaluation and site visits to selected residences. We evaluated distances to power lines up to 2000 m and included consideration of lower voltages (60–69 kV). Distance measures based on GIS and Google Earth evaluation showed close agreement (Pearson correlation >0.99). Our three-tiered approach to exposure assessment allowed us to achieve high specificity, which is crucial for studies of rare diseases with low exposure prevalence. PMID:24045429
Nakai, Ryuichiro; Salisbury, Cleo M; Rosen, Hugh; Cravatt, Benjamin F
2009-02-01
High-throughput screening (HTS) has become an integral part of academic and industrial efforts aimed at developing new chemical probes and drugs. These screens typically generate several 'hits', or lead active compounds, that must be prioritized for follow-up medicinal chemistry studies. Among primary considerations for ranking lead compounds is selectivity for the intended target, especially among mechanistically related proteins. Here, we show how the chemical proteomic technology activity-based protein profiling (ABPP) can serve as a universal assay to rank HTS hits based on their selectivity across many members of an enzyme superfamily. As a case study, four metalloproteinase-13 (MMP13) inhibitors of similar potency originating from a publically supported HTS and reported in PubChem were tested by ABPP for selectivity against a panel of 27 diverse metalloproteases. The inhibitors could be readily separated into two groups: (1) those that were active against several metalloproteases and (2) those that showed high selectivity for MMP13. The latter set of inhibitors was thereby designated as more suitable for future medicinal chemistry optimization. We anticipate that ABPP will find general utility as a platform to rank the selectivity of lead compounds emerging from HTS assays for a wide variety of enzymes.
Castaño-Vinyals, Gemma; Nieuwenhuijsen, Mark J; Moreno, Víctor; Carrasco, Estela; Guinó, Elisabet; Kogevinas, Manolis; Villanueva, Cristina M
2011-01-01
Low participation rates in the selection of population controls are an increasing concern for the validity of case-control studies worldwide. We conducted a pilot study to assess two approaches to recruiting population controls in a study of colorectal cancer, including a face-to-face interview and blood sample collection. In the first approach, persons identified through a population roster were invited to participate through a telephone call by an interviewer telephoning on behalf of our research center. In the second approach, individuals were identified from the lists of selected family practitioners and were telephoned on behalf of the family practitioner. When the second method was used, participation rates increased from 42% to 57% and the percentage of refusals decreased from 47% to 13%. The reasons for refusing to participate did not differ significantly between the two methods. Contact through the family practitioner yielded higher response rates in population controls in the study area. 2010 SESPAS. Published by Elsevier Espana. All rights reserved.
Jing, X; Cimino, J J
2014-01-01
Graphical displays can make data more understandable; however, large graphs can challenge human comprehension. We have previously described a filtering method to provide high-level summary views of large data sets. In this paper we demonstrate our method for setting and selecting thresholds to limit graph size while retaining important information by applying it to large single and paired data sets, taken from patient and bibliographic databases. Four case studies are used to illustrate our method. The data are either patient discharge diagnoses (coded using the International Classification of Diseases, Clinical Modifications [ICD9-CM]) or Medline citations (coded using the Medical Subject Headings [MeSH]). We use combinations of different thresholds to obtain filtered graphs for detailed analysis. The thresholds setting and selection, such as thresholds for node counts, class counts, ratio values, p values (for diff data sets), and percentiles of selected class count thresholds, are demonstrated with details in case studies. The main steps include: data preparation, data manipulation, computation, and threshold selection and visualization. We also describe the data models for different types of thresholds and the considerations for thresholds selection. The filtered graphs are 1%-3% of the size of the original graphs. For our case studies, the graphs provide 1) the most heavily used ICD9-CM codes, 2) the codes with most patients in a research hospital in 2011, 3) a profile of publications on "heavily represented topics" in MEDLINE in 2011, and 4) validated knowledge about adverse effects of the medication of rosiglitazone and new interesting areas in the ICD9-CM hierarchy associated with patients taking the medication of pioglitazone. Our filtering method reduces large graphs to a manageable size by removing relatively unimportant nodes. The graphical method provides summary views based on computation of usage frequency and semantic context of hierarchical terminology. The method is applicable to large data sets (such as a hundred thousand records or more) and can be used to generate new hypotheses from data sets coded with hierarchical terminologies.
Unbiased geocoding of maternal residence is critical to the success of an ongoing case-control study of exposure to five criteria air pollutants and the risk of selected birth defects in seven Texas counties between 1997 and 2000. The geocoded residence at delivery will be used ...
Case Studies of Selected Cooperative Adult Education Programs.
ERIC Educational Resources Information Center
Moore, Allen B., Ed.; And Others
Third in a series of five, the document presents case study reports of site visits to cooperative adult education programs. The five locations visited included programs between: (1) Wharton County Junior College and Johnson Testers, Inc. (Texas); (2) Louisiana State Department of Education and B. F. Trappey and Sons (Louisiana); (3) Grand Rapids…
A Case Study of MOOCs Design and Administration at Seoul National University
ERIC Educational Resources Information Center
Lim, Cheolil; Kim, Sunyoung; Kim, Mihwa; Han, Songlee; Seo, Seungil
2014-01-01
This research, based on the case study of edX at Seoul National University, which is running Korea's first Massive Open Online Courses (MOOCs), discussed and proposed the roles of principal facilitators, the process, and the relationships among various facilitators in selecting, designing, opening and administrating MOOCs classes. Researches on…
His Trail of Silence: A Case Study in Reaching a Child Who Refused To Speak.
ERIC Educational Resources Information Center
Van Antwerp, Kathleen
1999-01-01
Discusses selective mutism, a childhood disorder characterized by persistent failure to speak in specific social situations. Details a case study of one boy from kindergarten until treatment was received in 8th grade. Discusses techniques used in the communication process between the boy and his counselor. (Author/JDM)
Meaning Making with Picturebooks: Young Children's Use of Semiotic Resources
ERIC Educational Resources Information Center
Kachorsky, Dani; Moses, Lindsey; Serafini, Frank; Hoelting, Megan
2017-01-01
As part of a year-long, classroom-based research study examining literacy instruction and development, the research team observed emerging decoders draw from a range of semiotic resources while reading picturebooks. Utilizing a case study approach, the researchers selected eight first graders to act as a representative case, and examined their…
Abstract: This case study application provides discussion on a selected application of advanced concepts, included in the End of Asset Life Reinvestment decision-making process tool, using Milwaukee Metropolitan Sewer District (MMSD) pump and motor data sets. The tool provides s...
Introduction: Unbiased geocoding of maternal residence is critical to the success of an ongoing population-based case-control study of exposure to five criteria air pollutants and the risk of selected birth defects in seven Texas counties between 1997 and 2000. The geocoded res...
An approach for integrating toxicogenomic data in risk assessment: The dibutyl phthalate case study
DOE Office of Scientific and Technical Information (OSTI.GOV)
Euling, Susan Y., E-mail: euling.susan@epa.gov; Thompson, Chad M.; Chiu, Weihsueh A.
An approach for evaluating and integrating genomic data in chemical risk assessment was developed based on the lessons learned from performing a case study for the chemical dibutyl phthalate. A case study prototype approach was first developed in accordance with EPA guidance and recommendations of the scientific community. Dibutyl phthalate (DBP) was selected for the case study exercise. The scoping phase of the dibutyl phthalate case study was conducted by considering the available DBP genomic data, taken together with the entire data set, for whether they could inform various risk assessment aspects, such as toxicodynamics, toxicokinetics, and dose–response. A descriptionmore » of weighing the available dibutyl phthalate data set for utility in risk assessment provides an example for considering genomic data for future chemical assessments. As a result of conducting the scoping process, two questions—Do the DBP toxicogenomic data inform 1) the mechanisms or modes of action?, and 2) the interspecies differences in toxicodynamics?—were selected to focus the case study exercise. Principles of the general approach include considering the genomics data in conjunction with all other data to determine their ability to inform the various qualitative and/or quantitative aspects of risk assessment, and evaluating the relationship between the available genomic and toxicity outcome data with respect to study comparability and phenotypic anchoring. Based on experience from the DBP case study, recommendations and a general approach for integrating genomic data in chemical assessment were developed to advance the broader effort to utilize 21st century data in risk assessment. - Highlights: • Performed DBP case study for integrating genomic data in risk assessment • Present approach for considering genomic data in chemical risk assessment • Present recommendations for use of genomic data in chemical risk assessment.« less
Knüppel, Sven; Meidtner, Karina; Arregui, Maria; Holzhütter, Hermann-Georg; Boeing, Heiner
2015-07-01
Analyzing multiple single nucleotide polymorphisms (SNPs) is a promising approach to finding genetic effects beyond single-locus associations. We proposed the use of multilocus stepwise regression (MSR) to screen for allele combinations as a method to model joint effects, and compared the results with the often used genetic risk score (GRS), conventional stepwise selection, and the shrinkage method LASSO. In contrast to MSR, the GRS, conventional stepwise selection, and LASSO model each genotype by the risk allele doses. We reanalyzed 20 unlinked SNPs related to type 2 diabetes (T2D) in the EPIC-Potsdam case-cohort study (760 cases, 2193 noncases). No SNP-SNP interactions and no nonlinear effects were found. Two SNP combinations selected by MSR (Nagelkerke's R² = 0.050 and 0.048) included eight SNPs with mean allele combination frequency of 2%. GRS and stepwise selection selected nearly the same SNP combinations consisting of 12 and 13 SNPs (Nagelkerke's R² ranged from 0.020 to 0.029). LASSO showed similar results. The MSR method showed the best model fit measured by Nagelkerke's R² suggesting that further improvement may render this method a useful tool in genetic research. However, our comparison suggests that the GRS is a simple way to model genetic effects since it does not consider linkage, SNP-SNP interactions, and no non-linear effects. © 2015 John Wiley & Sons Ltd/University College London.
Effect of Impact Location on the Response of Shuttle Wing Leading Edge Panel 9
NASA Technical Reports Server (NTRS)
Lyle, Karen H.; Spellman, Regina L.; Hardy, Robin C.; Fasanella, Edwin L.; Jackson, Karen E.
2005-01-01
The objective of this paper is to compare the results of several simulations performed to determine the worst-case location for a foam impact on the Space Shuttle wing leading edge. The simulations were performed using the commercial non-linear transient dynamic finite element code, LS-DYNA. These simulations represent the first in a series of parametric studies performed to support the selection of the worst-case impact scenario. Panel 9 was selected for this study to enable comparisons with previous simulations performed during the Columbia Accident Investigation. The projectile for this study is a 5.5-in cube of typical external tank foam weighing 0.23 lb. Seven locations spanning the panel surface were impacted with the foam cube. For each of these cases, the foam was traveling at 1000 ft/s directly aft, along the orbiter X-axis. Results compared from the parametric studies included strains, contact forces, and material energies for various simulations. The results show that the worst case impact location was on the top surface, near the apex.
A Psycholinguistic Description of the Development of Writing in Selected First Grade Students.
ERIC Educational Resources Information Center
Milz, Vera E.
A study was conducted to examine writing development in first grade children. The writings from an entire classroom were collected. From these, six children's writings were chosen for cross-sectional analysis. Two children from this group were then selected for further in-depth case studies. Interviews, parent surveys, and observations were used…
USDA-ARS?s Scientific Manuscript database
Genomic selection (GS) is an attractive technology to generate rapid genetic gains, particularly in perennial grass species like switchgrass, where phenotyping generally requires at least two years of field trial. In this study, we empirically assessed prediction procedures for GS in two different p...
ERIC Educational Resources Information Center
Ward, Cherie A.
2015-01-01
This study examined the use of poetry as a multimodal communicative text to encourage reading engagement in selected African-American learners with mild intellectual disabilities. Framed by critical discourse theory, genre theory, and Gardner's theory of multiple intelligences, this investigation presented poetry as an alternative text…
Dysthymia among Substance Abusers: An Exploratory Study of Individual and Mental Health Factors
ERIC Educational Resources Information Center
Diaz, Naelys; Horton, Eloise G.; McIlveen, John; Weiner, Michael; Nelson, Jenniffer
2009-01-01
The purpose of this study was to examine the individual characteristics and mental health factors of dysthymic and nondysthymic substance abusers. Out of a total of 1,209 medical records reviewed to select cases of dysthymic and nondysthymic substance abusers attending a community drug treatment program, 183 medical records were selected, 48% of…
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shrestha, R.M.; Biswas, W.K.; Jalal, A.I.
1998-11-01
This paper assesses the potential of selected efficient electrical appliances for avoiding power generation and for mitigation of selected air pollutants from the power sector in Pakistan from technical as well as national, utility and user perspectives. The study shows that about 14, 21 and 35% of the total CO{sub 2}, SO{sub 2} and NO{sub x} emissions in the business as usual (BAU) case could be avoided by the adoption of selected efficient appliances during 1997--2015 from the national perspective, while the corresponding figures from the user perspective are 12, 17 and 29%, respectively. All selected efficient appliances would bemore » cost effective to the users if electricity prices were set at the long-run marginal cost of supply.« less
Falinski, Mark M; Plata, Desiree L; Chopra, Shauhrat S; Theis, Thomas L; Gilbertson, Leanne M; Zimmerman, Julie B
2018-04-30
Engineered nanomaterials (ENMs) and ENM-enabled products have emerged as potentially high-performance replacements to conventional materials and chemicals. As such, there is an urgent need to incorporate environmental and human health objectives into ENM selection and design processes. Here, an adapted framework based on the Ashby material selection strategy is presented as an enhanced selection and design process, which includes functional performance as well as environmental and human health considerations. The utility of this framework is demonstrated through two case studies, the design and selection of antimicrobial substances and conductive polymers, including ENMs, ENM-enabled products and their alternatives. Further, these case studies consider both the comparative efficacy and impacts at two scales: (i) a broad scale, where chemical/material classes are readily compared for primary decision-making, and (ii) within a chemical/material class, where physicochemical properties are manipulated to tailor the desired performance and environmental impact profile. Development and implementation of this framework can inform decision-making for the implementation of ENMs to facilitate promising applications and prevent unintended consequences.
Sub-Selective Quantization for Learning Binary Codes in Large-Scale Image Search.
Li, Yeqing; Liu, Wei; Huang, Junzhou
2018-06-01
Recently with the explosive growth of visual content on the Internet, large-scale image search has attracted intensive attention. It has been shown that mapping high-dimensional image descriptors to compact binary codes can lead to considerable efficiency gains in both storage and performing similarity computation of images. However, most existing methods still suffer from expensive training devoted to large-scale binary code learning. To address this issue, we propose a sub-selection based matrix manipulation algorithm, which can significantly reduce the computational cost of code learning. As case studies, we apply the sub-selection algorithm to several popular quantization techniques including cases using linear and nonlinear mappings. Crucially, we can justify the resulting sub-selective quantization by proving its theoretic properties. Extensive experiments are carried out on three image benchmarks with up to one million samples, corroborating the efficacy of the sub-selective quantization method in terms of image retrieval.
ERIC Educational Resources Information Center
Fleming, Allison R.; Boeltzig-Brown, Heike; Foley, Susan M.
2015-01-01
Purpose: We describe a modified Delphi method used to select effective state vocational rehabilitation agency practices to prioritize rehabilitation services for individuals with most significant disabilities within the context of Order of Selection, an area where there is little known and published. Specifically, we describe how we applied the…
Evaluating the Navy’s Enlisted Accessions Testing Program Based on Future Talent Needs
2017-03-01
Increased Fit ....... 36 2. Better Team Leader Selection ......................................... 37 3. Enhancing Teamwork Effectiveness through the...40 3. Case Study No. 3—Navy SEALs: Selecting and Training for an Elite Fighting Force...and potential importance of using personality traits’ information as a mechanism for selecting recruits with the appropriate attributes for
A comparison of stand structure and composition following selective-harvest at Byrne-Milliron Forest
Amy K. Petersen; Will Russell
2017-01-01
The effects of selective-harvest on forest composition and structure in the southern range of the coast redwood (Sequoia sempervirens (D. Don) Endl.) forest have not been well documented. This case study focused on the Byrne-Milliron Forest in Santa Cruz County, California where selective-harvest is currently the primary method of timber extraction...
ERIC Educational Resources Information Center
Holmes, Monica C.; Jenicke, Lawrence O.; Hempel, Jessica L.
2015-01-01
Purpose: This paper discusses the importance of the Six Sigma selection process, describes a Six Sigma project in a higher educational institution and presents a weighted scorecard approach for project selection. Design/Methodology/Approach: A case study of the Six Sigma approach being used to improve student support at a university computer help…
DEVELOPING AN INTEGRATED MANAGEMENT SYSTEM FOR URBAN AND ENERGY PLANNING TOWARDS A LOW-CARBON CITY
NASA Astrophysics Data System (ADS)
Maeda, Hideto; Nakakubo, Toyohiko; Tokai, Akihiro
In this study, we developed an integrated management model that supports local government to make a promising energy saving measure on a block-scale combined with urban planning. We applied the model to Osaka city and estimated CO2 emissions from the residential and commercial buildings to 2050. The urban renewal cases selected in this study included advanced multipole accumulation case, normal multipole accumulation case, and actual trend continuation case. The energy saving options introduced in each case included all-electric HP system, micro grid system, and we also set the option where the greater CO2 reduction one is selected in each block. The results showed that CO2 emission in 2050 would be reduced by 54.8-57.6% relative to the actual condition by introducing the new energy system in all cases. In addition, the amount of CO2 reduction in actual trend continuation case was highest. The major factor was that the effect of CO2 emission reductions by installing the solar power generation panel was higher than the effect by utilizing heated water mutually on the high-density blocks in terms of total urban buildings' energy consumption.
Something's Fishy in Paxton Lake: A Case on Speciation in Sticklebacks.
ERIC Educational Resources Information Center
Sharp, Joan
2002-01-01
Introduces a case study on speciation and evolutionary mechanisms. Teaches science process skills as well as natural selection, biological species concepts, basic genetic terminology, and classification. Includes teaching notes and classroom management strategies. (Contains 14 references.) (YDS)
[Review of 1,172 clinical cases with human communication disorders].
de Díaz, M R; de Pustilnik, N F; Tortolero, Y
1976-01-01
The study comprised 1,172 clinical cases that were classified according to sex, age and speech disorders. A review is made on the most common alterations that they present, the selective treatment in each type and their rehabilitation.
ERIC Educational Resources Information Center
Zhao, Wei
2016-01-01
This study selects postgraduate students in the first grade as the participants, based on their needs analysis, classroom presentations and performance of assignments completion, through the methodology of case study, the results show that students at the university level even the graduate levels still struggle with academic English. Thus, this…
Teaching Excellence and Innovative Practices: A Case Study of National Awardee Teachers of India
ERIC Educational Resources Information Center
Sengupta, Aparajita; Tyagi, Harish Kumar
2016-01-01
Aim: The study intended to identify the contributions of the National awardee teachers to the teaching learning process through their teaching excellence and innovative practices which can act as exemplary model for the entire teaching community. Method: Attempts has been made to carry out a qualitative study where two selected cases are based on…
Reflections on Teaching Periodic Table Concepts: A Case Study of Selected Schools in South Africa
ERIC Educational Resources Information Center
Mokiwa, Hamza Omari
2017-01-01
The Periodic Table of Elements is central to the study of modern Physics and Chemistry. It is however, considered by teachers as difficult to teach. This paper reports on a case study exploring reflections on teaching periodic table concepts in five secondary schools from South Africa. Qualitative methodology of interviews and document analysis…
Child Protection and Justice Systems Processing of Serious Child Abuse and Neglect Cases
ERIC Educational Resources Information Center
Sedlak, Andrea J.; Schultz, Dana; Wells, Susan J.; Lyons, Peter; Doueck, Howard J.; Gragg, Frances
2006-01-01
Objective: The aim of this study was to examine the trajectory of cases through four systems: child protection, law enforcement, the dependency courts, and the criminal courts. Method: This study focused on a county selected from a 41-county telephone survey conducted for the National Incidence Study of Child Abuse and Neglect (NIS-3). For this…
ERIC Educational Resources Information Center
Angotta, Jill E.
2013-01-01
This study is an exploratory case study on supervisors' and front line managers' current practices towards the promotion of the socialization of employees with disabilities with their non-disabled peers. The researcher interviewed eight participants, four men and four women, purposefully selected from Connecticut and Indiana in person or over the…
ERIC Educational Resources Information Center
Manogharan, Melissa Wane; Thivaharan, Thinagaran; Rahman, Radziah Abd
2018-01-01
This case study attempts to identify the reasons for high turnover of academic staff in private higher institutions especially in small colleges. Three small colleges that shared almost the same type of background were being selected to participate in this study. The academic coordinator from these three institutions was interviewed. This case…
The Mentoring Experience of Nontraditional Students: A Case Study in Higher Education
ERIC Educational Resources Information Center
Langer, Arthur
2008-01-01
The purpose of this study was to select an institution that has mandated mentoring as part of its mission and to examine students' perceptions of the mentoring they received. The study selected Empire State College (ESC), a college that is part of the State of New York University system in the USA. ESC is an institution with a 36-year history of…
ERIC Educational Resources Information Center
Mabula, Salyungu
2015-01-01
This study investigated the performance of secondary school students in Mathematics at the Selected Secondary Schools in Mtwara Municipality and Ilemela District by Absenteeism, Conduct, Type of School and Gender as explanatory Factors. The data used in the study was collected from documented records of 250 form three students with 1:1 gender…
ERIC Educational Resources Information Center
Shamaki, Timothy Ado
2015-01-01
The purpose of the study was to determine the influence of learning environment on students' academic achievement in mathematics at senior secondary school level. Thus the study investigated some components of learning environment and their possible influence on students' academic achievement in mathematics. A sample of 337 randomly selected SS II…
Field investigation of influenza vaccine effectiveness on morbidity.
Carrat, F; Tachet, A; Rouzioux, C; Housset, B; Valleron, A J
1998-01-01
Our objective was to evaluate influenza vaccine effectiveness during an influenza epidemic by means of a matched case-control study. The study was performed by 35 general practitioners who collected specimens for influenza virus testing from 610 patients who consulted for infectious syndrome: 168 (28%) were influenza-positive. Two designs were used for selecting controls to take into account the high incidence-rate of influenza-like illness and the various possible protective effects of the vaccine. A first disease-free control matched for age and sex was selected during the same week as the case. A second control matched for age and sex was selected at the end of the epidemic period, irrespective of disease history during the epidemic period. Upper and lower bounds of vaccine effectiveness can be derived from these case-control designs. After adjustment for chronic conditions and exposure to an index case, analysis of the matched-pairs whose case was influenza-positive showed, with the first group of controls, an influenza vaccine effectiveness of 68% (95% CI, 10% to 88%) and, in the second group, 53% (95% CI, -19% to 82%). Among the pairs whose case was negative for influenza, vaccine effectiveness was, respectively, 31% (95% CI, -17% to 59%) and 12% (95% CI, -47% to 47%). Vaccine effectiveness was highest for the H3N2 subtype whose vaccine strain was identical to that of the wild-type strain. The results suggest that influenza vaccine is effective in the field in preventing influenza morbidity.
Case studies for GSHP demonstration projects in the US
Liu, Xiaobing; Malhotra, Mini; Im, Piljae
2015-07-01
Under the American Recovery and Reinvestment Act , twenty-six ground source heat pump (GSHP) projects were competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This article gives an overview of the case studies for six of the systems. These case studies evaluated efficiencies, energy savings, and costs of the demonstrated systems. In addition, it was found that more energy savings could be achieved if controls of GSHP system are improved.
ERIC Educational Resources Information Center
Jenkins, Rebecca Torrance
2017-01-01
This article is the first of a two-part series that explores science teachers' and their pupils' experiences of using different pedagogical approaches based on understandings of how brains learn. For this case-study research, nine science teachers were interviewed and four teachers self-selected to trial a pedagogical approach, new to them, from…
Subcortical mechanisms in language: lexical-semantic mechanisms and the thalamus.
Crosson, B
1999-07-01
Four previously published cases of dominant thalamic lesion in which the author has participated are reviewed to gain a better understanding of thalamic participation in lexical-semantic functions. Naming deficits in two cases support Nadeau and Crosson's (1997) hypothesis of a selective engagement mechanism involving the frontal lobes, inferior thalamic peduncle, nucleus reticularis, and other thalamic nuclei, possibly the centromedian nucleus. This mechanism selectively engages those cortical areas required to perform a cognitive task, while maintaining other areas in a state of relative disengagement. Deficits in selective engagement disproportionately affect lexical retrieval based on semantic input, as opposed to lexical and sublexical processes, because the former is more dependent upon this attentional system. The concept of selective engagement is also useful in understanding thalamic participation in working memory, as supported by data from one recent functional neuroimaging study. Other processes also may be compromised in more posterior thalamic lesions which damage the pulvinar but not other components of this selective engagement system. A third case with aphasia after a more superior and posterior thalamic lesion also had oral reading errors similar to those in neglect dyslexia. The pattern of deficits suggested a visual processing problem in the early stages of reading. The fourth case had a category-specific naming deficit after posterior thalamic lesion. Taken together, the latter two cases indicate that the nature of language functions in more posterior regions of the dominant thalamus depends upon the cortical connectivity of the thalamic region. Together, findings from the four cases suggest that thalamic nuclei and systems are involved in multiple processes which directly or indirectly support cortical language functions. Copyright 1999 Academic Press.
Novel and efficient tag SNPs selection algorithms.
Chen, Wen-Pei; Hung, Che-Lun; Tsai, Suh-Jen Jane; Lin, Yaw-Ling
2014-01-01
SNPs are the most abundant forms of genetic variations amongst species; the association studies between complex diseases and SNPs or haplotypes have received great attention. However, these studies are restricted by the cost of genotyping all SNPs; thus, it is necessary to find smaller subsets, or tag SNPs, representing the rest of the SNPs. In fact, the existing tag SNP selection algorithms are notoriously time-consuming. An efficient algorithm for tag SNP selection was presented, which was applied to analyze the HapMap YRI data. The experimental results show that the proposed algorithm can achieve better performance than the existing tag SNP selection algorithms; in most cases, this proposed algorithm is at least ten times faster than the existing methods. In many cases, when the redundant ratio of the block is high, the proposed algorithm can even be thousands times faster than the previously known methods. Tools and web services for haplotype block analysis integrated by hadoop MapReduce framework are also developed using the proposed algorithm as computation kernels.
NASA Astrophysics Data System (ADS)
Zarindast, Atousa; Seyed Hosseini, Seyed Mohamad; Pishvaee, Mir Saman
2017-06-01
Robust supplier selection problem, in a scenario-based approach has been proposed, when the demand and exchange rates are subject to uncertainties. First, a deterministic multi-objective mixed integer linear programming is developed; then, the robust counterpart of the proposed mixed integer linear programming is presented using the recent extension in robust optimization theory. We discuss decision variables, respectively, by a two-stage stochastic planning model, a robust stochastic optimization planning model which integrates worst case scenario in modeling approach and finally by equivalent deterministic planning model. The experimental study is carried out to compare the performances of the three models. Robust model resulted in remarkable cost saving and it illustrated that to cope with such uncertainties, we should consider them in advance in our planning. In our case study different supplier were selected due to this uncertainties and since supplier selection is a strategic decision, it is crucial to consider these uncertainties in planning approach.
Design considerations for near-infrared filter photometry: effects of noise sources and selectivity.
Tarumi, Toshiyasu; Amerov, Airat K; Arnold, Mark A; Small, Gary W
2009-06-01
Optimal filter design of two-channel near-infrared filter photometers is investigated for simulated two-component systems consisting of an analyte and a spectrally overlapping interferent. The degree of overlap between the analyte and interferent bands is varied over three levels. The optimal design is obtained for three cases: a source or background flicker noise limited case, a shot noise limited case, and a detector noise limited case. Conventional photometers consist of narrow-band optical filters with their bands located at discrete wavelengths. However, the use of broadband optical filters with overlapping responses has been proposed to obtain as much signal as possible from a weak and broad analyte band typical of near-infrared absorptions. One question regarding the use of broadband optical filters with overlapping responses is the selectivity achieved by such filters. The selectivity of two-channel photometers is evaluated on the basis of the angle between the analyte and interferent vectors in the space spanned by the relative change recorded for each of the two detector channels. This study shows that for the shot noise limited or detector noise limited cases, the slight decrease in selectivity with the use of broadband optical filters can be compensated by the higher signal-to-noise ratio afforded by the use of such filters. For the source noise limited case, the best quantitative results are obtained with the use of narrow-band non-overlapping optical filters.
A Step-by-Step Guide to Propensity Score Matching in R
ERIC Educational Resources Information Center
Randolph, Justus J.; Falbe, Kristina; Manuel, Austin Kureethara; Balloun, Joseph L.
2014-01-01
Propensity score matching is a statistical technique in which a treatment case is matched with one or more control cases based on each case's propensity score. This matching can help strengthen causal arguments in quasi-experimental and observational studies by reducing selection bias. In this article we concentrate on how to conduct propensity…
Sargeant, Jan; Thomas, M. Kate; Fazil, Aamir
2014-01-01
Abstract Objective: This was a systematic review and meta-analysis to determine the proportion of Escherichia coli O157 cases that develop chronic sequelae. Data Sources: We conducted a systematic review of articles published prior to July 2011 in Pubmed, Agricola, CabDirect, or Food Safety and Technology Abstracts. Study Selection: Studies were selected that reported the number of E. coli O157 cases that developed reactive arthritis (ReA), hemolytic uremic syndrome (HUS), irritable bowel syndrome, inflammatory bowel disease, or Guillain Barré syndrome. Methods: Three levels of screening and data extraction of articles were conducted using predefined data fields. Meta-analysis was performed on unique outcome measures using a random-effects model, and heterogeneity was assessed using the I2 value. Meta-regression was used to explore the influence of nine study-level variables on heterogeneity. Results: A total of 82 studies were identified reporting 141 different outcome measures; 81 reported on HUS and one reported on ReA. Depending on the number of cases of E. coli O157, the estimate for the proportion of E. coli O157 cases that develop HUS ranged from 17.2% in extra-small studies (<50 cases) to 4.2% in extra-large studies (>1000 cases). Heterogeneity was significantly associated with group size (p<0.0001); however, the majority of the heterogeneity was unexplained. Conclusions: High unexplained heterogeneity indicated that the study-level factors examined had a minimal influence on the variation of estimates reported. PMID:24404780
Tubularized proximally-incised plate in distal/midshaft hypospadias repair.
Marte, Antonio; Pintozzi, Lucia
2017-06-23
The aim of this study was to verify the validity, feasibility, and the functional results, by uroflowmetry, of Tubularized proximallyincised plate technique in selected case of distal/midshaft hypospadias. Out of 120 patients scheduled to undergo TIP (or Snodgrass) procedure, 23 were selected between January 2013 and January 2016 (19.1%). This case series comprised 16 patients with distal and 7 with midshaft hypospadias. Mean age at surgery was 2.9 years. The inclusion criteria were a deep and wide glandular groove and a proximal narrow urethral plate. The procedure was carried out as described by Snodgrass but the incision of the urethral plate, including the mucosal and submucosal tissue, was made only proximally, between the original meatus and the glandular groove in no case extending to the entire length of the plate. Postoperatively a foley catheter was left in place from 4 to 7 days. Uroflowmetry was performed when the patients age ranged from 2.5 to 5.7 years (mean age 3.11 years and mean follow-up 1.8 years, body surface 2). No patient presented fistulas nor perioperative complications. At uroflowmetry, eighteen patients presented values above the 25th percentile and 5 showed a borderline flow. All patients in this group remained stable without urinary symptoms. In selected cases, the tubularized proximally-incised plate yields satisfactory cosmetic and functional results for the treatment of midshaft proximal hypospadias. A long-term follow-up study is needed for further evaluation. Patient selection is crucial for the success of this technique.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Warren, B.K.; Campbell, K.D.
Methane oxidative coupling studies were carried out in an atmospheric quartz reactor at temperatures between 700 and 800/degree/C. New catalysts prepared and studied included doped alkaline earth catalysts, lanthanide oxides, and proprietary catalysts. Neodymium oxide, Nd/sub 2/O/sub 3/, was found to be as active and selective as samarium oxide, Sm/sub 2/O/sub 3/, in contrast to literature reports. Proprietary Union Carbide catalysts (UCC-S:1) showed initial methane conversions and C/sub 2/ selectivities comparable to literature catalysts. Atypically low carbon dioxide to carbon monoxide ratios (typically ten times lower than those seen in the literature or other catalysts tested) and high ethylene tomore » ethane ratios (3 to 6 compared to typical literature ratios below 1) were obtained. These results are interesting because ethylene is more valuable than ethane and carbon monoxide is more valuable than carbon dioxide. With these UCC-S:1 catalysts, rapid deactivation was coupled with an observed shift in product ratios toward those more typical in the literature. Initial cases for process conceptualization studies were selected. The Comparison Case will consist of the conversion sequence from methane to synthesis gas to methanol to olefins to liquid hydrocarbon fuels. Case 1 will consist of the conversion of methane to ethylene and ethane. Case 2 will be the direct conversion of methane to C/sub 2/'s followed by conversion to liquid hydrocarbon fuels. 7 figs., 18 tabs.« less
Self-selection and moral hazard in Chilean health insurance.
Sapelli, Claudio; Vial, Bernardita
2003-05-01
We study the existence of self-selection and moral hazard in the Chilean health insurance industry. Dependent workers must purchase health insurance either from one public or several private insurance providers. For them, we analyze the relationship between health care services utilization and the choice of either private or public insurance. In the case of independent workers, where there is no mandate, we analyze the relationship between utilization and the decision to voluntarily purchase health insurance. The results show self-selection against insurance companies for independent workers, and against public insurance for dependent workers. Moral hazard is negligible in the case of hospitalization, but for medical visits, it is quantitatively important.
Usability Assessment of Educational Software by Students: Case of "?Pón-Ìm?`" in Osun State, Nigeria
ERIC Educational Resources Information Center
Tijani, O. K.
2016-01-01
This study investigated usability of educational software: case of "?pón-Ìm?`" in Osun state, Nigeria. Specifically, the study investigated influences of gender and school locations on students' assessment of "?pón-Ìm?`" Technology Enhanced Learning System (OTELS) based on selected usability parameters. 701 students were…
Students' Research Experiences during Consulting Projects: Three Themes Emerging from Case Studies
ERIC Educational Resources Information Center
Phillips, Carissa M. Holler
2010-01-01
Student consulting projects, an advanced form of problem-based learning, allow students to apply the skills developed in their classes on behalf of client organizations. A review of selected case studies in business education and other management education literature shows that research is an integral part of this consulting process. More than…
ERIC Educational Resources Information Center
Zucca, Gary; And Others
National University and Sierra College Small Business Development Center (SBDC) have jointly developed a program whereby small businesses become clients of the SBDC and are screened and selected as "living case studies" for National University's practicum for bachelor's and master's of business administration candidates. The new course replaces a…
Federal Register 2010, 2011, 2012, 2013, 2014
2010-05-21
...; and Prepare several case studies on the competitive position of selected U.S. environmental goods... environmental goods of significant export and/or commercial interest to the United States. Each case study will... appear at the public hearing. September 14, 2010: Deadline for filing pre-hearing briefs and statements...
ERIC Educational Resources Information Center
Kovtun, Olena; Stick, Sheldon
2009-01-01
This paper discusses the results of a case study exploring perceptions of selected administrators and instructors at a Ukrainian state institution regarding the effectiveness of the Bologna Process at their institution. Data were collected from focus group interviews with five volunteer instructors involved in the implementation process. The…
Current Trends in Microform Use by Secondary Schools: Four Case Studies.
ERIC Educational Resources Information Center
Lee, Thomas Graham
The case study section of this booklet discusses a number of current microform programs in secondary schools. The remainder of the booklet presents an overview of microform activity, including comments on the history of secondary school microform utilization and an up-to-date listing of microform selection aids. The amount of information available…
Cell Phone Video Recording Feature as a Language Learning Tool: A Case Study
ERIC Educational Resources Information Center
Gromik, Nicolas A.
2012-01-01
This paper reports on a case study conducted at a Japanese national university. Nine participants used the video recording feature on their cell phones to produce weekly video productions. The task required that participants produce one 30-second video on a teacher-selected topic. Observations revealed the process of video creation with a cell…
Abstract:This case study application provides discussion on a selected application of advanced concepts, included in the End of Asset Life Reinvestment decision-making process tool, using a utility practitioner’s data set. The tool provides step-by-step process guidance to the as...
Factors Affecting Women's Decisions to Pursue an IS Degree: A Case Study
ERIC Educational Resources Information Center
Serapiglia, Constance Patricia; Lenox, Terri L.
2010-01-01
The declining participation of women in the computer-related professions is a concern to academia and business. There appears to be a complex set of factors influencing the selection of a major and completing the degree. A case study of 25 undergraduate women explored, in detail, the events, conditions, and relationships that affected the decision…
A Case Control Study of Suicide and Attempted Suicide in Older Adults.
ERIC Educational Resources Information Center
Beautrais, Annette L.
2002-01-01
Risk factors for serious suicidal behavior among older adults were examined in a case control study of adults aged 55 and older who died by suicide or made suicide attempts and who were compared with randomly selected comparison subjects. Multivariate analyses suggested that mood disorders were the most significant risk factor for suicidal…
Without Women No Development: Selected Case Studies from Asia of Non-Formal Education for Women.
ERIC Educational Resources Information Center
Shah, Madhuri, Ed.
This handbook presents 15 case studies on the non-formal education of women from four Asian countries: India, Bangladesh, Sri Lanka, and Malaysia. The goal of this publication is to provide information about education-related issues concerning women and girls and development. This information is intended for those people, in governmental and…
ERIC Educational Resources Information Center
Chochezi, Victoire S.
2013-01-01
This qualitative multiple case study examined diversity perceptions of California community college senior leaders and sought to provide insights into how a senior leader's view of diversity concepts influences their actions in succession planning and selection of leaders and faculty. An in-depth qualitative analysis of participant interviews and…
Nutritional Status of Children with Autism Spectrum Disorders (ASDs): A Case-Control Study
ERIC Educational Resources Information Center
Marí-Bauset, Salvador; Llopis-González, Agustín; Zazpe-García, Itziar; Marí-Sanchis, Amelia; Morales-Suárez-Varela, María
2015-01-01
Children with autism spectrum disorder (ASD) have problems of food selectivity, implying risks of nutritional deficiencies. The aim was to compare intakes of macro and micronutrients and body mass index in ASD and typically developing (TD) children. In a case--control study, 3-day food diaries and anthropometric measurements were completed for ASD…
2004-03-01
phenomenology , ethnography , case study , and grounded theory (Creswell, 2003:183). These strategies help the researcher focus on data collection, data...was to select an appropriate tradition of inquiry (Creswell, 1998:21). The five traditions of inquiry are ethnography , grounded theory , case study ... Phenomenology A Grounded Theory An Ethnography Figure 7. Differentiating Tradition by Foci
Promoting Democratic Citizenship through Non-Formal Adult Education: The Case of Denmark
ERIC Educational Resources Information Center
Milana, Marcella; Sorensen, Tore Bernt
2009-01-01
The article presents selected findings from in-depth case studies of two non-formal learning activities organized by the Danish Folk High Schools and Day High Schools, respectively. The purpose of the empirical study was to investigate how longstanding, non-formal, adult education institutions have worked to foster the acquisition of civic…
Purposes and Approaches of Selected Mentors in School-Based Mentoring: A Collective Case Study
ERIC Educational Resources Information Center
Frels, Rebecca K.; Onwuegbuzie, Anthony J.; Bustamante, Rebecca M.; Garza, Yvonne; Nelson, Judith A.; Nichter, Mary; Leggett, Elsa Soto
2013-01-01
Over the last decade, community leaders have connected with students through school-based mentoring (SBM) programs (e.g., adults who mentor at-risk students). However, research in the area of SBM is only on the cusp of understanding relationship elements for impacting youth. In this collective case study, we examined the perceptions and…
Introduction to Command, Control and Communications (C3) Through Comparative Case Analysis
1990-03-01
enhancing the process of learning from experience. Case study allows the student to apply concepts , theories, and techniques to an actual incident within...part of the thesis describes selected principles and concepts of 33 related to cormruication management, interoperability, command structure and...The solutions to the cases require applying the principles and concepts presented in the first rart. The four cases are: (1) the Iran hostage rescue
Fong, Sim S.; Rearden, Preshious; Kanchagar, Chitra; Sassetti, Christopher; Trevejo, Jose; Brereton, Richard G.
2013-01-01
A gas chromatography–differential mobility spectrometer (GC-DMS) involves a portable and selective mass analyzer that may be applied to chemical detection in the field. Existing approaches examine whole profiles and do not attempt to resolve peaks. A new approach for peak detection in the 2D GC-DMS chromatograms is reported. This method is demonstrated on three case studies: a simulated case study; a case study of headspace gas analysis of Mycobacterium tuberculosis (MTb) cultures consisting of three matching GC-DMS and GC-MS chromatograms; a case study consisting of 41 GC-DMS chromatograms of headspace gas analysis of MTb culture and media. PMID:21204557
93 Years of stand density and land-use legacy research at the Coulter Ranch Study Site
Andrew J. Sanchez Meador; Margaret M. Moore
2008-01-01
In 1913, the Fort Valley Experimental Forest initiated an unprecedented case-study experiment to determine the effects of harvesting methods on tree regeneration and growth on a ponderosa pine-Gambel oak forest at Coulter Ranch in northern Arizona. The harvesting methods examined were seed-tree, group selection, and light selection. In addition, the effects of...
A Case Analysis of an Elementary School's Implementation of Response to Intervention
ERIC Educational Resources Information Center
White, Richard B.; Polly, Drew; Audette, Robert H.
2012-01-01
The study provides an illustration of an elementary school's implementation of a model of Response to Intervention (RTI). The school was selected to be the pilot for RTI implementation within the district. The study employed interviews of all members of the school RTI Leadership Team and select members of the district-level RTI Leadership Team. An…
ERIC Educational Resources Information Center
Benson, Shanelle R.
2010-01-01
Purpose. The purpose of this study was to determine, to what degree, African American teachers in five selected, urban charter schools in New York performed the historical roles of counselor, advocate, disciplinarian, surrogate parent, and role model in, to determine how African American Teachers perceived the importance of performing the…
ERIC Educational Resources Information Center
Krauss, George E.
2009-01-01
The purpose of this study is to understand how selected insurance practitioners learn and developed in their practices setting. The selected insurance practitioners (collectively customer service representatives, insurance agents, and risk managers) are responsible for the counseling and placement of insurance products and the implementation of…
ERIC Educational Resources Information Center
Machumu, Haruni J.; Kaitila, Mafwimbo M.
2014-01-01
This study reports on the kind of school leadership style that best suits for promoting teachers' job satisfaction in primary schools in Tanzania. The study employed cross sectional research design with samples of 200 teachers from 20 selected primary schools in Songea and Morogoro districts. Interviews, documentary analysis and questionnaires…
A re-evaluation of a case-control model with contaminated controls for resource selection studies
Christopher T. Rota; Joshua J. Millspaugh; Dylan C. Kesler; Chad P. Lehman; Mark A. Rumble; Catherine M. B. Jachowski
2013-01-01
A common sampling design in resource selection studies involves measuring resource attributes at sample units used by an animal and at sample units considered available for use. Few models can estimate the absolute probability of using a sample unit from such data, but such approaches are generally preferred over statistical methods that estimate a relative probability...
Pediatric Feeding Disorders: A Quantitative Synthesis of Treatment Outcomes
ERIC Educational Resources Information Center
Sharp, William G.; Jaquess, David L.; Morton, Jane F.; Herzinger, Caitlin V.
2010-01-01
A systematic review of the literature regarding treatment of pediatric feeding disorders was conducted. Articles in peer-reviewed scientific journals (1970-2010) evaluating treatment of severe food refusal or selectivity were identified. Studies demonstrating strict experimental control were selected and analyzed. Forty-eight single-case research…
Arévalo Suarez, Fernando; Cárdenas Vela, Irene; Rodríguez Rodríguez, Kriss; Pérez Narrea, María Teresa; Rodríguez Vargas, Omar; Montes Teves, Pedro; Monge Salgado, Eduardo
2014-04-01
to describe the clinical, endoscopic, and histological characteristics of rectal mucosal prolapse syndrome, formerly known as Solitary rectal ulcer, in patients from a general hospital. All patient diagnosed as rectal mucosal prolapse syndrome during 2010-2013 was selected; the medical history war reviewed and the histological slides were reevaluated by two pathologists. 17 cases of rectal mucosal prolapse syndrome were selected, the majority were males under 50 years, the most common clinical findings were rectal bleeding (82%) and constipation (65%), the endocopic findings were heterogeneous,: erythema (41%), ulcers (35%) and elevated lesions (29%). All cases presented fibromuscularhyperplasia in lamina propia and crypt distortion in the microscopic evaluation. In our study of rectal mucosal prolapse syndrome. The most common clinical findings were rectal bleeding and constipation. Erythematous mucosa was the most common endoscopic finding.
ERIC Educational Resources Information Center
Facon, Bruno; Sahiri, Safia; Riviere, Vinca
2008-01-01
The aim of the present study was to demonstrate the efficacy of combining two operant learning procedures--shaping and fading--for treating selective mutism. The participant was a 12-year-old boy with mental retardation presenting a severe long-term selective mutism. The treatment was aimed at increasing the loudness of his vocalizations in an…
ERIC Educational Resources Information Center
Franklin, Marian Pope, Comp.
Over 400 journal articles, case studies, research reports, dissertations, and position papers are briefly described in a series of eight selected bibliographies related to school organization. The eight specific areas treated in the volume and the number of items listed for each include: nongraded elementary school organization, 96; nongraded…
Neil I Lamson; H. Clay Smith; H. Clay Smith
1991-01-01
Appalachian hardwood stands in West Virginia were managed for 30 or more years using single-tree selection regeneration practices. Stand yield data suggest that current stand growth will provide economical harvest cuts for several future cutting cycles. This case study indicates that the single-tree selection practice has potential for landowners who want to maintain...
Twinn, Sheila; Thompson, David R; Lopez, Violeta; Lee, Diana T F; Shiu, Ann T Y
2005-01-01
Different factors have been shown to influence the development of models of advanced nursing practice (ANP) in primary-care settings. Although ANP is being developed in hospitals in Hong Kong, China, it remains undeveloped in primary care and little is known about the factors determining the development of such a model. The aims of the present study were to investigate the contribution of different models of nursing practice to the care provided in primary-care settings in Hong Kong, and to examine the determinants influencing the development of a model of ANP in such settings. A multiple case study design was selected using both qualitative and quantitative methods of data collection. Sampling methods reflected the population groups and stage of the case study. Sampling included a total population of 41 nurses from whom a secondary volunteer sample was drawn for face-to-face interviews. In each case study, a convenience sample of 70 patients were recruited, from whom 10 were selected purposively for a semi-structured telephone interview. An opportunistic sample of healthcare professionals was also selected. The within-case and cross-case analysis demonstrated four major determinants influencing the development of ANP: (1) current models of nursing practice; (2) the use of skills mix; (3) the perceived contribution of ANP to patient care; and (4) patients' expectations of care. The level of autonomy of individual nurses was considered particularly important. These determinants were used to develop a model of ANP for a primary-care setting. In conclusion, although the findings highlight the complexity determining the development and implementation of ANP in primary care, the proposed model suggests that definitions of advanced practice are appropriate to a range of practice models and cultural settings. However, the findings highlight the importance of assessing the effectiveness of such models in terms of cost and long-term patient outcomes.
Platz, Elizabeth A.; Kulac, Ibrahim; Barber, John R.; Drake, Charles G.; Joshu, Corinne E.; Nelson, William G.; Lucia, M. Scott; Klein, Eric A.; Lippman, Scott M.; Parnes, Howard L.; Thompson, Ian M.; Goodman, Phyllis J.; Tangen, Catherine M.; De Marzo, Angelo M.
2017-01-01
Background We leveraged two trials to test the hypothesis of an inflammation-prostate cancer link prospectively in men without indication for biopsy. Methods Prostate Cancer Prevention Trial (PCPT) participants who had an end-of-study biopsy performed per protocol that was negative for cancer and who subsequently enrolled in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) were eligible. We selected all 100 cases and sampled 200 frequency-matched controls and used PCPT end-of-study biopsies as “baseline”. Five men with PSA >4 ng/mL at end-of-study biopsy were excluded. Tissue was located for 92 cases and 193 controls. We visually assessed inflammation in benign tissue. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression adjusting for age and race. Results Mean time between biopsy and diagnosis was 5.9 years. In men previously in the PCPT placebo arm, 78.1% of cases (N=41) and 68.2% of controls (N=85) had at least one baseline biopsy core (~5 evaluated per man) with inflammation. The odds of prostate cancer (N=41 cases) appeared to increase with increasing mean percentage of tissue area with inflammation, a trend that was statistically significant for Gleason sum <4+3 disease (N=31 cases; versus 0%, >0–<1.8% OR=1.70, 1.8%–<5.0% OR=2.39, ≥5% OR=3.31, p-trend=0.047). In men previously in the finasteride arm, prevalence of inflammation did not differ between cases (76.5%; N=51) and controls (75.0%; N=108). Conclusions Benign tissue inflammation was positively associated with prostate cancer. Impact This first prospective study of men without biopsy indication supports the hypothesis that inflammation influences prostate cancer development. PMID:28754796
ERIC Educational Resources Information Center
Haghshenas, Mahsa Sadat Mousavi; Hashemian, Mahmood
2016-01-01
This study examined the effect of etymological elaboration, pictorial elucidation, and integration of these 2 strategies on idiom learning by L2 learners. A total number of 80 homogeneous intermediate learners studying English at 3 language institutes in Isfahan, Iran, were selected. The intermediate participants were selected as the result of…
ERIC Educational Resources Information Center
Yöndem, Sadik
2015-01-01
The aim of this study is to examine post-graduate thesis completed on guitar in Turkey. For this purpose, a total of 89 theses were investigated in terms of selected research topics, study participants, and methods for analysis. For the selection of the thesis included in this study three criteria were used; first, theses from 1990 (beginning time…
ERIC Educational Resources Information Center
Blanchard, Weedens E.
2017-01-01
The purpose of this research case study was to examine a post-secondary pilot program that provides education to select New York City homeless adults at a private university. In this study, the researcher examined how the Academy program assists homeless and disadvantaged adults to obtain post-graduate employment opportunities through academic…
ERIC Educational Resources Information Center
Xiang, Lin
2011-01-01
This is a collective case study seeking to develop detailed descriptions of how programming an agent-based simulation influences a group of 8th grade students' model-based inquiry (MBI) by examining students' agent-based programmable modeling (ABPM) processes and the learning outcomes. The context of the present study was a biology unit on…
Association between Helicobacter pylori infection and increased risk of typhoid fever.
Bhan, Maharaj K; Bahl, Rajiv; Sazawal, Sunil; Sinha, Anju; Kumar, Ramesh; Mahalanabis, Dilip; Clemens, John D
2002-12-15
Helicobacter pylori infection has been reported to increase the risk of cholera. This nested case-control study was conducted to determine whether H. pylori infection is associated with occurrence of typhoid fever. Eighty-three case subjects of culture-proven typhoid fever were identified through a 1-year surveillance of subjects aged 0-40 years in an urban slum. Two age- and sex-matched neighborhood control subjects were concurrently selected for each case subject. Serum anti-H. pylori immunoglobulin G antibodies were measured in case and neighborhood control subjects. For determining other risk factors, 2 additional community control subjects per case were selected. There was a significant association between the presence of serum anti-H. pylori immunoglobulin G antibodies and typhoid fever (adjusted odds ratio, 2.03; 95% confidence interval, 1.02-4.01). Illiteracy, being part of a nuclear family, nonuse of soap, and consumption of ice cream were also associated with a significantly greater risk of typhoid fever. This study provides the first empiric evidence that H. pylori infection is associated with an increased risk of typhoid fever.
2017-06-01
case study in a northeastern American metropolitan area. METHODOLOGY : The ROAMS platform provides expanded analysis, model automation, and enhanced...shoals. An initial route for such operations is selected much like the military logistics case . Subsequent adjustments to routes may be done on an ad...IX-45 June 2017 8 CASE STUDY: The ROAMS platform was applied to a large, northeast American metropolitan region to demonstrate the capability of
Wang, Mingming; Sweetapple, Chris; Fu, Guangtao; Farmani, Raziyeh; Butler, David
2017-10-01
This paper presents a new framework for decision making in sustainable drainage system (SuDS) scheme design. It integrates resilience, hydraulic performance, pollution control, rainwater usage, energy analysis, greenhouse gas (GHG) emissions and costs, and has 12 indicators. The multi-criteria analysis methods of entropy weight and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) were selected to support SuDS scheme selection. The effectiveness of the framework is demonstrated with a SuDS case in China. Indicators used include flood volume, flood duration, a hydraulic performance indicator, cost and resilience. Resilience is an important design consideration, and it supports scheme selection in the case study. The proposed framework will help a decision maker to choose an appropriate design scheme for implementation without subjectivity. Copyright © 2017 Elsevier Ltd. All rights reserved.
Non-operative management of abdominal gunshot injuries: Is it safe in all cases?
İflazoğlu, Nidal; Üreyen, Orhan; Öner, Osman Zekai; Meral, Ulvi Mehmet; Yülüklü, Murat
2018-01-01
In line with advances in diagnostic methods and expectation of a decrease in the number of negative laparotomies, selective non-operative management of abdominal gunshot wounds has been increasingly used over the last three decades. We aim to detect the possibility of treatment without surgery and present our experience in selected cases referred from Syria to a hospital at the Turkish-Syrian border. Between February 2012 and June 2014, patients admitted with abdominal gunshot wounds were analyzed. Computed tomography was performed for all patients on admission. Patients who were hemodynamically stable and did not have symptoms of peritonitis at the time of presentation were included in the study. The primary outcome parameters were mortality and morbidity. Successful selective non-operative management (Group 1) and unsuccessful selective non-operative management (Group 2) groups were compared in terms of complications, blood transfusion, injury site, injury severity score (ISS), and hospital stay. Of 158 truncal injury patients, 18 were considered feasible for selective non-operative management. Of these, 14 (78%) patients were treated without surgery. Other Four patients were operated upon progressively increasing abdominal pain and tenderness during follow-up. On diagnostic exploration, all of these cases had intestinal perforations. No mortality was observed in selective non-operative management. There was no statistically significant difference between Group 1 and Group 2, in terms of length of hospital stay (96 and 127 h, respectively). Also, there was no difference between groups in terms of blood transfusion necessity, injury site, complication rate, and injury severity score (p>0.05). Decision making on patient selection for selective non-operative management is critical to ensure favorable outcomes. It is not possible to predict the success of selective non-operative management in advance. Cautious clinical examination and close monitoring of these patients is vital; however, emergency laparotomy should be performed in case of change in vital signs and positive symptoms concerning peritonitis.
Jouhet, V; Defossez, G; Ingrand, P
2013-01-01
The aim of this study was to develop and evaluate a selection algorithm of relevant records for the notification of incident cases of cancer on the basis of the individual data available in a multi-source information system. This work was conducted on data for the year 2008 in the general cancer registry of Poitou-Charentes region (France). The selection algorithm hierarchizes information according to its level of relevance for tumoral topography and tumoral morphology independently. The selected data are combined to form composite records. These records are then grouped in respect with the notification rules of the International Agency for Research on Cancer for multiple primary cancers. The evaluation, based on recall, precision and F-measure confronted cases validated manually by the registry's physicians with tumours notified with and without records selection. The analysis involved 12,346 tumours validated among 11,971 individuals. The data used were hospital discharge data (104,474 records), pathology data (21,851 records), healthcare insurance data (7508 records) and cancer care centre's data (686 records). The selection algorithm permitted performances improvement for notification of tumour topography (F-measure 0.926 with vs. 0.857 without selection) and tumour morphology (F-measure 0.805 with vs. 0.750 without selection). These results show that selection of information according to its origin is efficient in reducing noise generated by imprecise coding. Further research is needed for solving the semantic problems relating to the integration of heterogeneous data and the use of non-structured information.
Jurek, Anne M; Maldonado, George; Greenland, Sander
2013-03-01
Special care must be taken when adjusting for outcome misclassification in case-control data. Basic adjustment formulas using either sensitivity and specificity or predictive values (as with external validation data) do not account for the fact that controls are sampled from a much larger pool of potential controls. A parallel problem arises in surveys and cohort studies in which participation or loss is outcome related. We review this problem and provide simple methods to adjust for outcome misclassification in case-control studies, and illustrate the methods in a case-control birth certificate study of cleft lip/palate and maternal cigarette smoking during pregnancy. Adjustment formulas for outcome misclassification that ignore case-control sampling can yield severely biased results. In the data we examined, the magnitude of error caused by not accounting for sampling is small when population sensitivity and specificity are high, but increases as (1) population sensitivity decreases, (2) population specificity decreases, and (3) the magnitude of the differentiality increases. Failing to account for case-control sampling can result in an odds ratio adjusted for outcome misclassification that is either too high or too low. One needs to account for outcome-related selection (such as case-control sampling) when adjusting for outcome misclassification using external information. Copyright © 2013 Elsevier Inc. All rights reserved.
IT vendor selection model by using structural equation model & analytical hierarchy process
NASA Astrophysics Data System (ADS)
Maitra, Sarit; Dominic, P. D. D.
2012-11-01
Selecting and evaluating the right vendors is imperative for an organization's global marketplace competitiveness. Improper selection and evaluation of potential vendors can dwarf an organization's supply chain performance. Numerous studies have demonstrated that firms consider multiple criteria when selecting key vendors. This research intends to develop a new hybrid model for vendor selection process with better decision making. The new proposed model provides a suitable tool for assisting decision makers and managers to make the right decisions and select the most suitable vendor. This paper proposes a Hybrid model based on Structural Equation Model (SEM) and Analytical Hierarchy Process (AHP) for long-term strategic vendor selection problems. The five steps framework of the model has been designed after the thorough literature study. The proposed hybrid model will be applied using a real life case study to assess its effectiveness. In addition, What-if analysis technique will be used for model validation purpose.
Lacourt, Aude; Cardis, Elisabeth; Pintos, Javier; Richardson, Lesley; Kincl, Laurel; Benke, Geza; Fleming, Sarah; Hours, Martine; Krewski, Daniel; McLean, Dave; Parent, Marie-Elise; Sadetzki, Siegal; Schlaefer, Klaus; Schlehofer, Brigitte; Lavoue, Jerome; van Tongeren, Martie; Siemiatycki, Jack
2013-04-12
The aim was to investigate possible associations between glioma (an aggressive type of brain cancer) and occupational exposure to selected agents: combustion products (diesel and gasoline exhaust emissions, benzo(a)pyrene), dusts (animal dust, asbestos, crystalline silica, wood dust) and some other chemical agents (formaldehyde, oil mist, sulphur dioxide). The INTEROCC study included cases diagnosed with glioma during 2000-2004 in sub-regions of seven countries. Population controls, selected from various sampling frames in different centers, were frequency or individually matched to cases by sex, age and center. Face-to-face interviews with the subject or a proxy respondent were conducted by trained interviewers. Detailed information was collected on socio-economic and lifestyle characteristics, medical history and work history. Occupational exposure to the 10 selected agents was assessed by a job exposure matrix (JEM) which provides estimates of the probability and level of exposure for different occupations. Using a 25% probability of exposure in a given occupation in the JEM as the threshold for considering a worker exposed, the lifetime prevalence of exposure varied from about 1% to about 15% for the different agents. Associations between glioma and each of the 10 agents were estimated by conditional logistic regression, and using three separate exposure indices: i) ever vs. never; ii) lifetime cumulative exposure; iii) total duration of exposure. The study sample consisted of 1,800 glioma cases and 5,160 controls. Most odds ratio estimates were close to the null value. None of the ten agents displayed a significantly increased odds ratio nor any indication of dose-response relationships with cumulative exposure or with duration of exposure. Thus, there was no evidence that these exposures influence risk of glioma.
[Indicators of healthcare quality in day surgery (2010-2012)].
Martínez Rodenas, F; Codina Grifell, J; Deulofeu Quintana, P; Garrido Corchón, J; Blasco Casares, F; Gibanel Garanto, X; Cuixart Vilamajó, L; de Haro Licer, J; Vazquez Dorrego, X
2014-01-01
Monitoring quality indicators in Ambulatory Surgery centers is fundamental in order to identify problems, correct them and prevent them. Given their large number, it is essential to select the most valid ones. The objectives of the study are the continuous improvement in the quality of healthcare of day-case surgery in our center, by monitoring selective quality parameters, having periodic information on the results and taking corrective measures, as well as achieving a percentage of unplanned transfer and cancellations within quality standards. Prospective, observational and descriptive study of the day-case surgery carried out from January 2010 to December 2012. Unplanned hospital admissions and cancellations on the same day of the operation were selected and monitored, along with their reasons. Hospital admissions were classified as: inappropriate selection, medical-surgical complications, and others. The results were evaluated each year and statistically analysed using χ(2) tests. A total of 8,300 patients underwent day surgery during the 3 years studied. The day-case surgery and outpatient index increased by 5.4 and 6.4%, respectively (P<.01). Unexpected hospital admissions gradually decreased due to the lower number of complications (P<.01). Hospital admissions, due to an extended period of time in locoregional anaesthesia recovery, also decreased (P<.01). There was improved prevention of nausea and vomiting, and of poorly controlled pain. The proportion of afternoon admissions was significantly reduced (P<.01). The cancellations increased in 2011 (P<.01). The monitoring of quality parameters in day-case surgery has been a useful tool in our clinical and quality management. Globally, the unplanned transfer and cancellations have been within the quality standards and many of the indicators analysed have improved. Copyright © 2013 SECA. Published by Elsevier Espana. All rights reserved.
Career Construction with a Gay Client: A Case Study
ERIC Educational Resources Information Center
Maree, Jacobus Gideon
2014-01-01
This article reports on the value of career construction counselling (CCC) with a gay person. The participant was selected purposively, with the selection criteria calling for a mid-career woman who had sought career counselling. The intervention involved administration of the "Career Construction Interview" (CCI) and the creation of a…
Selective robust optimization: A new intensity-modulated proton therapy optimization strategy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Yupeng; Niemela, Perttu; Siljamaki, Sami
2015-08-15
Purpose: To develop a new robust optimization strategy for intensity-modulated proton therapy as an important step in translating robust proton treatment planning from research to clinical applications. Methods: In selective robust optimization, a worst-case-based robust optimization algorithm is extended, and terms of the objective function are selectively computed from either the worst-case dose or the nominal dose. Two lung cancer cases and one head and neck cancer case were used to demonstrate the practical significance of the proposed robust planning strategy. The lung cancer cases had minimal tumor motion less than 5 mm, and, for the demonstration of the methodology,more » are assumed to be static. Results: Selective robust optimization achieved robust clinical target volume (CTV) coverage and at the same time increased nominal planning target volume coverage to 95.8%, compared to the 84.6% coverage achieved with CTV-based robust optimization in one of the lung cases. In the other lung case, the maximum dose in selective robust optimization was lowered from a dose of 131.3% in the CTV-based robust optimization to 113.6%. Selective robust optimization provided robust CTV coverage in the head and neck case, and at the same time improved controls over isodose distribution so that clinical requirements may be readily met. Conclusions: Selective robust optimization may provide the flexibility and capability necessary for meeting various clinical requirements in addition to achieving the required plan robustness in practical proton treatment planning settings.« less
Ren, Y M; Wu, X M; Wen, Y; Lai, Q; Chen, W Z; Qian, Y X; Liang, R G
2017-01-03
Objective: To explore the causes and countermeasure in recurrent bleeding following the selective renal artery embolization treating post-percutaneous nephrolithotomy hemorrhage. Methods: A total of 334 patients of severe renal hemorrhage associated with percutaneous nephrolithotomy (PCNL) from March 2011 to April 2015 were analyzed retrospectively.All the patients underwent super selective angiography and renal artery embolization.The causes of recurrent hemorrhage were analyzed and principles for diagnosis and embolization were studied. Results: The initial embolization was performed in 329 cases hospitalized in the First Affiliated Hospital of Guangzhou Medical University and 318 cases were successfully stopped bleeding with a hemostatic rate of 96.7 %(318/329). Of total 334 consecutive cases, there were 16 cases of recurrent renal hemorrhage, 11 cases were initially embolized in this hospital, and otherwise the other 5 cases were in other hospitals. Causes of recurrent hemorrhage were missed embolization of tiny pseudoaneurysm ( n =12), and two cases of 12, the tiny pseudoaneurysm were feeding by accessory renal arteries, undetected arteriovenous fistula( n =2), recanalization of the embolized arteries ( n =2). Conclusion: The causes of recurrent bleeding fallowing the initial selective renal artery embolization treating post-percutaneous nephrolithotomy hemorrhage are varied, and missed embolization of tiny pseudoaneurysm is the major cause of unsuccessful initial renal artery embolization. To strengthen the understanding of tiny pseudoaneurysm is helpful to improve the success rate of hemostasis.
The impact of using old germplasm on genetic merit and diversity-A cattle breed case study.
Eynard, Sonia E; Windig, Jack J; Hulsegge, Ina; Hiemstra, Sipke-Joost; Calus, Mario P L
2018-05-29
Artificial selection and high genetic gains in livestock breeds led to a loss of genetic diversity. Current genetic diversity conservation actions focus on long-term maintenance of breeds under selection. Gene banks play a role in such actions by storing genetic materials for future use and the recent development of genomic information is facilitating characterization of gene bank material for better use. Using the Meuse-Rhine-Issel Dutch cattle breed as a case study, we inferred the potential role of germplasm of old individuals for genetic diversity conservation of the current population. First, we described the evolution of genetic merit and diversity over time and then we applied the optimal contribution (OC) strategy to select individuals for maximizing genetic diversity, or maximizing genetic merit while constraining loss of genetic diversity. In the past decades, genetic merit increased while genetic diversity decreased. Genetic merit and diversity were both higher in an OC scenario restricting the rate of inbreeding when old individuals were considered for selection, compared to considering only animals from the current population. Thus, our study shows that gene bank material, in the form of old individuals, has the potential to support long-term maintenance and selection of breeds. © 2018 The Authors. Journal of Animal Breeding and Genetics Published by Blackwell Verlag GmbH.
The Use of Interrupted Case Studies to Enhance Critical Thinking Skills in Biology
White, Tracy K.; Whitaker, Paul; Gonya, Terri; Hein, Richard; Kroening, Dubear; Lee, Kevin; Lee, Laura; Lukowiak, Andrea; Hayes, Elizabeth
2009-01-01
There has been a dramatic increase in the availability of case studies for use in the biology classroom, and perceptions of the effectiveness of case-study-based learning are overwhelmingly positive. Here we report the results of a study in which we evaluated the ability of interrupted case studies to improve critical thinking in the context of experimental design and the conventions of data interpretation. Students were assessed using further case studies designed to evaluate their ability to recognize and articulate problematic approaches to these elements of experimentation. Our work reveals that case studies have broad utility in the classroom. In addition to demonstrating a small but statistically significant increase in the number of students capable of critically evaluating selected aspects of experimental design, we also observed increased student engagement and documented widespread misconceptions regarding the conventions of data acquisition and analysis. PMID:23653687
Crack Path Selection in Thermally Loaded Borosilicate/Steel Bibeam Specimen
DOE Office of Scientific and Technical Information (OSTI.GOV)
Grutzik, Scott Joseph; Reedy, Jr., E. D.
Here, we have developed a novel specimen for studying crack paths in glass. Under certain conditions, the specimen reaches a state where the crack must select between multiple paths satisfying the K II = 0 condition. This path selection is a simple but challenging benchmark case for both analytical and numerical methods of predicting crack propagation. We document the development of the specimen, using an uncracked and instrumented test case to study the effect of adhesive choice and validate the accuracy of both a simple beam theory model and a finite element model. In addition, we present preliminary fracture testmore » results and provide a comparison to the path predicted by two numerical methods (mesh restructuring and XFEM). The directional stability of the crack path and differences in kink angle predicted by various crack kinking criteria is analyzed with a finite element model.« less
Crack Path Selection in Thermally Loaded Borosilicate/Steel Bibeam Specimen
Grutzik, Scott Joseph; Reedy, Jr., E. D.
2017-08-04
Here, we have developed a novel specimen for studying crack paths in glass. Under certain conditions, the specimen reaches a state where the crack must select between multiple paths satisfying the K II = 0 condition. This path selection is a simple but challenging benchmark case for both analytical and numerical methods of predicting crack propagation. We document the development of the specimen, using an uncracked and instrumented test case to study the effect of adhesive choice and validate the accuracy of both a simple beam theory model and a finite element model. In addition, we present preliminary fracture testmore » results and provide a comparison to the path predicted by two numerical methods (mesh restructuring and XFEM). The directional stability of the crack path and differences in kink angle predicted by various crack kinking criteria is analyzed with a finite element model.« less
[Epidemiological methods used in studies in the prevalence of Tourette syndrome].
Stefanoff, Paweł; Mazurek, Jacek
2003-01-01
Tourette syndrome (TS) prevalence was studied since the early 80-ies. Its clinical course is characterised by co-occurrence of motor and vocal tics. Results of previous epidemiological studies were surprisingly divergent: the prevalence varied from 0.5 to 115 cases per 10,000 population. The disease previously recognised as extremely rare and severe is now considered as quite common, with often moderate course. Selected methods used in studies of TS prevalence and analysis of their possible impact on study results are presented. The studies were divided into 3 groups: studies of the hospitalised population, large-scale screenings and studies involving school population, basing on characteristic and size of population, methods of selection of subjects, diagnostic and screening methods used. Studies of the hospitalised population involved patients with most severe symptoms, in different age groups, different methods of final diagnosis confirmation were used. TS prevalence varied from 0.5 up to 15 cases per 10,000 population. Procedures used in large-scale screening studies made possible the elimination of potential selection bias. Large populations were studied using transparent and repetitive confirmation of diagnoses. Their validity was additionally checked in parallel validity studies. TS prevalence was in the range 4.3 to 10 cases per 10,000 population. The highest TS prevalence was obtained in studies involving schoolchildren. Data were gathered from multiple sources: from parents, teachers and children, as well as from classroom observation. Diagnoses were made by experienced clinicians. TS prevalence obtained in school population studies was between 36.2 up to 115 per 10,000 population.
ERIC Educational Resources Information Center
Broad, Mary L., Ed.
Organized in three parts, this book contains an introductory chapter and 17 case studies selected to show transfer applications in a wide range of organizational settings. In part 1, two chapters review the rationale, context, and research relating to transfer: "Transfer Concepts and Research Overview" (Mary Broad); and "Success Factors in…
ERIC Educational Resources Information Center
Hammond, Russell E.
2012-01-01
The case study engaged selected stakeholders who explored their perceptions and understanding of why they made significant commitments of volunteerism and philanthropy to a capital campaign at one public community college, and the particular factors that influenced their decisions. A paucity of inquiries examines this topic from the volunteer or…
Increasing market share through consumer marketing: a case study in obstetrics.
Kingsley, V H
1986-05-01
Consumers are becoming ever more selective in their choice of health care providers. Hospitals that are aware of local preferences and how to reach and influence consumers will gain a competitive advantage. Outlined in this article are consumer marketing techniques that can be utilized for all product lines. The concept is applied here as a case study in obstetrics.
ERIC Educational Resources Information Center
Willett, Michael S.
2013-01-01
The purpose of this exploratory longitudinal case study was to examine how the implementation of an Incentive Based Budgeting (IBB) system (i.e., Responsibility-Centered Management [RCM]) affected selected institutional performance indicators at the campus level and two comparable schools at a large Mid-Western public University. The value of…
ERIC Educational Resources Information Center
Ranker, Jason
2007-01-01
This case study closely examines how John (a former student of mine, age eight, second grade) composed during an informal writing group at school. Using qualitative research methods, I found that John selectively took up conventions, characters, story grammars, themes, and motifs from video games, television, Web pages, and comics. Likening his…
ERIC Educational Resources Information Center
Zhang, Ke
2015-01-01
This article starts with an overview on China's MOOC phenomenon and social media, and then reports a comparative, multiple case study on three selected MOOC communities that have emerged on social media in China. These representative MOOC communities included: (a) MOOC Academy, the largest MOOC community in China, (b) Zhejiang University of…
ERIC Educational Resources Information Center
Davis, Alan; Mitchell, Kara; Dray, Barbara; Keenan, Tracy
2012-01-01
Working in a research collaborative between Denver Public Schools and the University of Colorado Denver, the authors selected Bruce Randolph High School (BRHS) as a case study because of its growth on state academic achievement tests and because of its multilingual learners. After a difficult beginning, BRHS has established an inclusive culture of…
ERIC Educational Resources Information Center
Crittenden, Barry D.; England, Richard
2005-01-01
The principles and practices of environmental impact assessment are best taught to chemical engineering undergraduate students by means of a role-playing case study. Many suitable examples are available from public sources. The planning appeal process has been selected so as to introduce an adversarial style involving cross-examination on…
ERIC Educational Resources Information Center
Broome, Jeffrey L.
2013-01-01
The purpose of this research project is to investigate the design of classroom environments through the lens of a uniquely selected art educator. More specifically, the purpose is to use case study methodology (Stake, 1995) to characterize the resulting instructional experiences for an art educator who had the unique opportunity to collaborate…
ERIC Educational Resources Information Center
Canadian Education Association, 2016
2016-01-01
A Canadian Education Association (CEA) Selection Jury chose the Ottawa Catholic School Board (OCSB) out of 35 School District applicants from across Canada to participate in the 2015 "Innovation that Sticks" Case Study Program. From September to December 2015--through an Appreciative Inquiry interview process--the CEA researched how the…
A Case Study in Teacher-Centered Curriculum Development: The Process in Walpole Public Schools.
ERIC Educational Resources Information Center
Kline, Jane
In this case study illustrating teacher-centered curriculum development, teachers in the Walpole (Massachusetts) public school system were asked to select a reading program for use in grades K-8. Twenty-five teachers served on two teams over a two-year period. They used developmental learning kits at the kindergarten level, basal reading series…
USDA-ARS?s Scientific Manuscript database
To study the association of selected polymorphism in genes related to vitamin E, vitamin C, and glutathione peroxidase with these biomarkers and primary open-angle glaucoma (POAG) risk. A case-control study matched for age, sex, and bodyweight was undertaken. Two hundred fifty POAG cases and 250 con...
Middle-Aged Independent-Living African Americans' Selections for Advance Directives: A Case Study
ERIC Educational Resources Information Center
McDaniel, Brenda J.
2013-01-01
The purpose of this collective embedded qualitative case study was to examine the perspectives of three middle-aged independent-living African Americans who had participated in the process of advance care planning (ACP) and completed at least two advance directives (ADs), a Durable Power of Attorney for Health Care (DPAHC) and a Living Will (LW).…
ERIC Educational Resources Information Center
Stott, Angela; Hobden, Paul A.
2016-01-01
This article describes a case study of a gifted high achiever in learning science. This learner was selected on the assumption that drawing attention to the characteristics of a successful learner may improve learning effectiveness of less successful learners. The first author taught the gifted learner and collected data through participant…
ERIC Educational Resources Information Center
Pritchett, Mark S.
This paper presents a comprehensive case analysis of formal environmental scanning processes in three different institutions of higher education. The study focuses on how environmental scanning activities are organized and used to support institutional planning and decision-making. Special emphasis is placed on describing how environmental…
ERIC Educational Resources Information Center
Jones, Sara K.
2018-01-01
The purpose of this comparative case study was to examine the motivation for participation in traditional and non-traditional vocal ensembles by students who are not pursuing a career in music and the perceived benefits of this participation. Participants were selected from a traditional mixed choral ensemble and a student-run a cappella ensemble.…
ERIC Educational Resources Information Center
Jabaruddin; Alimuddin; Manda, Darman
2016-01-01
This research aims at determining educational values in families by describing the priority of the values selected in the educational value, the role of parents, and the socialization of values that were used by parents in educational values. This research is a case study with a qualitative approach. The subjects of the research were selected…
ERIC Educational Resources Information Center
Bond, Vanessa L.
2015-01-01
The purpose of this comparative case study was to investigate the use of music in two Reggio-inspired preschools in the United States. I used purposeful sampling to select two sites that represented contrasting sociocultural contexts: one urban school serving a Latino population from low socioeconomic backgrounds and one suburban early childhood…
Aguirre, Jacobo; Buldú, Javier M; Manrubia, Susanna C
2009-12-01
Networks of selectively neutral genotypes underlie the evolution of populations of replicators in constant environments. Previous theoretical analysis predicted that such populations will evolve toward highly connected regions of the genome space. We first study the evolution of populations of replicators on simple networks and quantify how the transient time to equilibrium depends on the initial distribution of sequences on the neutral network, on the topological properties of the latter, and on the mutation rate. Second, network neutrality is broken through the introduction of an energy for each sequence. This allows to study the competition between two features (neutrality and energetic stability) relevant for survival and subjected to different selective pressures. In cases where the two features are negatively correlated, the population experiences sudden migrations in the genome space for values of the relevant parameters that we calculate. The numerical study of larger networks indicates that the qualitative behavior to be expected in more realistic cases is already seen in representative examples of small networks.
NASA Astrophysics Data System (ADS)
Aguirre, Jacobo; Buldú, Javier M.; Manrubia, Susanna C.
2009-12-01
Networks of selectively neutral genotypes underlie the evolution of populations of replicators in constant environments. Previous theoretical analysis predicted that such populations will evolve toward highly connected regions of the genome space. We first study the evolution of populations of replicators on simple networks and quantify how the transient time to equilibrium depends on the initial distribution of sequences on the neutral network, on the topological properties of the latter, and on the mutation rate. Second, network neutrality is broken through the introduction of an energy for each sequence. This allows to study the competition between two features (neutrality and energetic stability) relevant for survival and subjected to different selective pressures. In cases where the two features are negatively correlated, the population experiences sudden migrations in the genome space for values of the relevant parameters that we calculate. The numerical study of larger networks indicates that the qualitative behavior to be expected in more realistic cases is already seen in representative examples of small networks.
93 years of stand density and land-use legacy research at the Coulter Ranch Study Site (P-53)
Andrew J. Sanchez Meador; Margaret M. Moore
2008-01-01
In 1913, the Fort Valley Experimental Forest initiated an unprecedented case-study experiment to determine the effects of harvesting methods on tree regeneration and growth on a ponderosa pine-Gambel oak forest at Coulter Ranch in northern Arizona. The harvesting methods examined were seed-tree, group selection, and light selection. In addition, the effects of...
ERIC Educational Resources Information Center
Anderson, Monika R.
2014-01-01
The purpose of this study was to use a variety of techniques and data sources, to describe and to compare the self-reported educational technology integration proficiency levels with the evidence-based educational technology integration practices among select elementary language arts teachers. A collective case study design (Stake, 1995) was used…
ERIC Educational Resources Information Center
Sancar Tokmak, Hatice; Ozgelen, Sinan
2013-01-01
This case study aimed to examine early childhood education (ECE) pre-service teachers' perception on the factors affecting integration of educational computer games to their instruction in two areas: selecting and redesigning. Twenty-six ECE pre-service teachers participated in the study. The data was collected through open-ended questionnaires,…
Evidence from Social Service Enhancement Projects: Selected Cases from Norway's HUSK Project.
Johannessen, Asbjorn; Eide, Solveig Botnen
2015-01-01
Through this article the authors describe the social service context of the HUSK (The University Research Program to Support Selected Municipal Social Service Offices) projects and briefly describe 10 of the 50 projects funded throughout the country. The welfare state context for the cases and the criteria for case selection are also provided. The 10 cases are organized into three categories that feature the role of dialogue, educational innovation, and service innovation. These cases provide the foundation for the analysis and implications located in the subsequent articles of the special issue.
ERIC Educational Resources Information Center
Wolbring, Tobias; Treischl, Edgar
2016-01-01
Systematic sampling error due to self-selection is a common topic in methodological research and a key challenge for every empirical study. Since selection bias is often not sufficiently considered as a potential flaw in research on and evaluations in higher education, the aim of this paper is to raise awareness for the topic using the case of…
Integrating qualitative research into occupational health: a case study among hospital workers.
Gordon, Deborah R; Ames, Genevieve M; Yen, Irene H; Gillen, Marion; Aust, Birgit; Rugulies, Reiner; Frank, John W; Blanc, Paul D
2005-04-01
We sought to better use qualitative approaches in occupational health research and integrate them with quantitative methods. We systematically reviewed, selected, and adapted qualitative research methods as part of a multisite study of the predictors and outcomes of work-related musculoskeletal disorders among hospital workers in two large urban tertiary hospitals. The methods selected included participant observation; informal, open-ended, and semistructured interviews with individuals or small groups; and archival study. The nature of the work and social life of the hospitals and the foci of the study all favored using more participant observation methods in the case study than initially anticipated. Exploiting the full methodological spectrum of qualitative methods in occupational health is increasingly relevant. Although labor-intensive, these approaches may increase the yield of established quantitative approaches otherwise used in isolation.
Orthodontic Treatment Timing and Modalities in Anterior Open Bite: Case Series Study
Al Hamadi, Wisam; Saleh, Fayez; Kaddouha, Mohamad
2017-01-01
Objective: The purpose of this study was to present early and adult cases of anterior open bite that were treated efficiently using different treatment approaches and mechanics. Materials and Methods: Five patients of different age groups (from 7 to 27 years), suffering from a clear Anterior open bite deformity, were properly diagnosed and relevant treatment modality for each was selected. Results: Positive overbite was efficiently achieved for all patients. Conclusion: Patient compliance is a key factor in using removable habit breakers. However, fixed palatal crib gave the same results but in shorter time. Anterior open bite of skeletal components should be thoroughly evaluated before selecting camouflage or orthognathic surgery treatment modality. PMID:29299074
Attrition Bias Related to Missing Outcome Data: A Longitudinal Simulation Study.
Lewin, Antoine; Brondeel, Ruben; Benmarhnia, Tarik; Thomas, Frédérique; Chaix, Basile
2018-01-01
Most longitudinal studies do not address potential selection biases due to selective attrition. Using empirical data and simulating additional attrition, we investigated the effectiveness of common approaches to handle missing outcome data from attrition in the association between individual education level and change in body mass index (BMI). Using data from the two waves of the French RECORD Cohort Study (N = 7,172), we first examined how inverse probability weighting (IPW) and multiple imputation handled missing outcome data from attrition in the observed data (stage 1). Second, simulating additional missing data in BMI at follow-up under various missing-at-random scenarios, we quantified the impact of attrition and assessed how multiple imputation performed compared to complete case analysis and to a perfectly specified IPW model as a gold standard (stage 2). With the observed data in stage 1, we found an inverse association between individual education and change in BMI, with complete case analysis, as well as with IPW and multiple imputation. When we simulated additional attrition under a missing-at-random pattern (stage 2), the bias increased with the magnitude of selective attrition, and multiple imputation was useless to address it. Our simulations revealed that selective attrition in the outcome heavily biased the association of interest. The present article contributes to raising awareness that for missing outcome data, multiple imputation does not do better than complete case analysis. More effort is thus needed during the design phase to understand attrition mechanisms by collecting information on the reasons for dropout.
Segmentation precedes face categorization under suboptimal conditions.
Van Den Boomen, Carlijn; Fahrenfort, Johannes J; Snijders, Tineke M; Kemner, Chantal
2015-01-01
Both categorization and segmentation processes play a crucial role in face perception. However, the functional relation between these subprocesses is currently unclear. The present study investigates the temporal relation between segmentation-related and category-selective responses in the brain, using electroencephalography (EEG). Surface segmentation and category content were both manipulated using texture-defined objects, including faces. This allowed us to study brain activity related to segmentation and to categorization. In the main experiment, participants viewed texture-defined objects for a duration of 800 ms. EEG results revealed that segmentation-related responses precede category-selective responses. Three additional experiments revealed that the presence and timing of categorization depends on stimulus properties and presentation duration. Photographic objects were presented for a long and short (92 ms) duration and evoked fast category-selective responses in both cases. On the other hand, presentation of texture-defined objects for a short duration only evoked segmentation-related but no category-selective responses. Category-selective responses were much slower when evoked by texture-defined than by photographic objects. We suggest that in case of categorization of objects under suboptimal conditions, such as when low-level stimulus properties are not sufficient for fast object categorization, segmentation facilitates the slower categorization process.
Segmentation precedes face categorization under suboptimal conditions
Van Den Boomen, Carlijn; Fahrenfort, Johannes J.; Snijders, Tineke M.; Kemner, Chantal
2015-01-01
Both categorization and segmentation processes play a crucial role in face perception. However, the functional relation between these subprocesses is currently unclear. The present study investigates the temporal relation between segmentation-related and category-selective responses in the brain, using electroencephalography (EEG). Surface segmentation and category content were both manipulated using texture-defined objects, including faces. This allowed us to study brain activity related to segmentation and to categorization. In the main experiment, participants viewed texture-defined objects for a duration of 800 ms. EEG results revealed that segmentation-related responses precede category-selective responses. Three additional experiments revealed that the presence and timing of categorization depends on stimulus properties and presentation duration. Photographic objects were presented for a long and short (92 ms) duration and evoked fast category-selective responses in both cases. On the other hand, presentation of texture-defined objects for a short duration only evoked segmentation-related but no category-selective responses. Category-selective responses were much slower when evoked by texture-defined than by photographic objects. We suggest that in case of categorization of objects under suboptimal conditions, such as when low-level stimulus properties are not sufficient for fast object categorization, segmentation facilitates the slower categorization process. PMID:26074838
Shuttle APS propellant thermal conditioner study
NASA Technical Reports Server (NTRS)
Fulton, D. L.
1971-01-01
The conditioner design concept selected for evaluation consists of an integral reactor and baffle-type heat exchanger. Heat exchange is accomplished by flowing reactor hot gases past a series of slotted and formed plates, through which the conditioned propellant flows. Heat transfer analysis has resulted in the selection of a reactor hot gas nominal mixture ratio of 1.0, giving a combustion temperature of 1560 F with a hydrogen inlet temperature of 275 R. Worst case conditions result in a combustion gas temperature of 2060 F, satisfying the condition of no damage to the conditioner in case of failure to flow cold fluid. In addition, evaluation of hot gas flow requirements and conditioner weight has resulted in the selection of a reactor hot gas exhaust temperature of 750 R.
ERIC Educational Resources Information Center
Ampratwum, Joseph; Offei, Yaw Nyadu; Ntoaduro, Afua
2016-01-01
The study aimed at exploring barriers to the use of computer assistive technology among students with visual impairment at Akropong School for the Blind. A case study design was adopted and the purposive sampling technique used to select 35 participants for the study. The researchers gathered qualitative data using an in-depth interview guide to…
ERIC Educational Resources Information Center
Green, Anthony; Hawkey, Roger
2012-01-01
The important yet under-researched role of item writers in the selection and adaptation of texts for high-stakes reading tests is investigated through a case study involving a group of trained item writers working on the International English Language Testing System (IELTS). In the first phase of the study, participants were invited to reflect in…
Retrospective Case Study in the Raton Basin, Colorado
Study site locations in Las Animas and Huerfano Counties were selected in response to ongoing complaints about changes in appearance, odor, and taste associated with drinking water in domestic wells. \
Use and interpretation of logistic regression in habitat-selection studies
Keating, Kim A.; Cherry, Steve
2004-01-01
Logistic regression is an important tool for wildlife habitat-selection studies, but the method frequently has been misapplied due to an inadequate understanding of the logistic model, its interpretation, and the influence of sampling design. To promote better use of this method, we review its application and interpretation under 3 sampling designs: random, case-control, and use-availability. Logistic regression is appropriate for habitat use-nonuse studies employing random sampling and can be used to directly model the conditional probability of use in such cases. Logistic regression also is appropriate for studies employing case-control sampling designs, but careful attention is required to interpret results correctly. Unless bias can be estimated or probability of use is small for all habitats, results of case-control studies should be interpreted as odds ratios, rather than probability of use or relative probability of use. When data are gathered under a use-availability design, logistic regression can be used to estimate approximate odds ratios if probability of use is small, at least on average. More generally, however, logistic regression is inappropriate for modeling habitat selection in use-availability studies. In particular, using logistic regression to fit the exponential model of Manly et al. (2002:100) does not guarantee maximum-likelihood estimates, valid probabilities, or valid likelihoods. We show that the resource selection function (RSF) commonly used for the exponential model is proportional to a logistic discriminant function. Thus, it may be used to rank habitats with respect to probability of use and to identify important habitat characteristics or their surrogates, but it is not guaranteed to be proportional to probability of use. Other problems associated with the exponential model also are discussed. We describe an alternative model based on Lancaster and Imbens (1996) that offers a method for estimating conditional probability of use in use-availability studies. Although promising, this model fails to converge to a unique solution in some important situations. Further work is needed to obtain a robust method that is broadly applicable to use-availability studies.
de Vocht, F; Campbell, R; Brennan, A; Mooney, J; Angus, C; Hickman, M
2016-03-01
Area-level public health interventions can be difficult to evaluate using natural experiments. We describe the use of propensity score matching (PSM) to select control local authority areas (LAU) to evaluate the public health impact of alcohol policies for (1) prospective evaluation of alcohol policies using area-level data, and (2) a novel two-stage quasi case-control design. Ecological. Alcohol-related indicator data (Local Alcohol Profiles for England, PHE Health Profiles and ONS data) were linked at LAU level. Six LAUs (Blackpool, Bradford, Bristol, Ipswich, Islington, and Newcastle-upon-Tyne) as sample intervention or case areas were matched to two control LAUs each using PSM. For the quasi case-control study a second stage was added aimed at obtaining maximum contrast in outcomes based on propensity scores. Matching was evaluated based on average standardized absolute mean differences (ASAM) and variable-specific P-values after matching. The six LAUs were matched to suitable control areas (with ASAM < 0.20, P-values >0.05 indicating good matching) for a prospective evaluation study that sought areas that were similar at baseline in order to assess whether a change in intervention exposure led to a change in the outcome (alcohol related harm). PSM also generated appropriate matches for a quasi case-control study--whereby the contrast in health outcomes between cases and control areas needed to be optimized in order to assess retrospectively whether differences in intervention exposure were associated with the outcome. The use of PSM for area-level alcohol policy evaluation, but also for other public health interventions, will improve the value of these evaluations by objective and quantitative selection of the most appropriate control areas. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
NASA Astrophysics Data System (ADS)
Nawi, Mohd Nasrun Mohd; Azimi, Mohd Azrulfitri; Pozin, Mohd Affendi Ahmad; Osman, Wan Nadri; Anuar, Herman Shah
2016-08-01
Project Management Consultancy (PMC) is part of the management oriented procurement method in which a sole consultant is hired by the client to deal with the contactors in place of the client. Appointing contractors in this method or approach looks to be interesting as client could play a pivotal role in evaluating and selecting the supplier/contractor for the work package. In some cases, client gives the authority for the PMC to hire the supplier/contractor of their choice while in some cases the client is the one who made the decision. This research paper seeks to investigate the dilemma arises from this situation and for the purpose of this research, a real case study was studied to assess the impacts of such dilemma to the performance of the project. Recommendations on how to tackle the dilemma will also be addressed in the later part of this research paper.
The functional role of the tonsils in speech.
Finkelstein, Y; Nachmani, A; Ophir, D
1994-08-01
To present illustrative cases showing various tonsillar influences on speech and to present a clinical method for patient evaluation establishing concepts of management and a rational therapeutic approach. The cases were selected from a group of approximately 1000 patients referred to the clinic because of suspected palatal diseases. Complete velopharyngeal assessment was made, including otolaryngologic, speech, and hearing examinations, polysomnography, nasendoscopy, multiview videofluoroscopy, and cephalometry. New observations further elucidate the intimate relation between the tonsils and the velopharyngeal valve. The potential influence of the tonsils on the velopharyngeal valve mechanism, in hindering or assisting speech, is described. In selected cases, the decision to perform tonsillectomy depends on its potential effect on speech. The combination of nasendoscopic and multiview videofluoroscopic studies of the mechanical properties of the tonsils during speech is required for patients who present with velopharyngeal insufficiency in whom tonsillar hypertrophy is found. These studies are also required in patients with palatal anomalies who are candidates for tonsillectomy.
Selection is stronger in early-versus-late stages of divergence in a Neotropical livebearing fish.
Ingley, Spencer J; Johnson, Jerald B
2016-03-01
How selection acts to drive trait evolution at different stages of divergence is of fundamental importance in our understanding of the origins of biodiversity. Yet, most studies have focused on a single point along an evolutionary trajectory. Here, we provide a case study evaluating the strength of divergent selection acting on life-history traits at early-versus-late stages of divergence in Brachyrhaphis fishes. We find that the difference in selection is stronger in the early-diverged population than the late-diverged population, and that trait differences acquired early are maintained over time. © 2016 The Author(s).
Variable selection in discrete survival models including heterogeneity.
Groll, Andreas; Tutz, Gerhard
2017-04-01
Several variable selection procedures are available for continuous time-to-event data. However, if time is measured in a discrete way and therefore many ties occur models for continuous time are inadequate. We propose penalized likelihood methods that perform efficient variable selection in discrete survival modeling with explicit modeling of the heterogeneity in the population. The method is based on a combination of ridge and lasso type penalties that are tailored to the case of discrete survival. The performance is studied in simulation studies and an application to the birth of the first child.
Optimal Contractor Selection in Construction Industry: The Fuzzy Way
NASA Astrophysics Data System (ADS)
Krishna Rao, M. V.; Kumar, V. S. S.; Rathish Kumar, P.
2018-02-01
A purely price-based approach to contractor selection has been identified as the root cause for many serious project delivery problems. Therefore, the capability of the contractor to execute the project should be evaluated using a multiple set of selection criteria including reputation, past performance, performance potential, financial soundness and other project specific criteria. An industry-wide questionnaire survey was conducted with the objective of identifying the important criteria for adoption in the selection process. In this work, a fuzzy set based model was developed for contractor prequalification/evaluation, by using effective criteria obtained from the percept of construction professionals, taking subjective judgments of decision makers also into consideration. A case study consisting of four alternatives (contractors in the present case) solicited from a public works department of Pondicherry in India, is used to illustrate the effectiveness of the proposed approach. The final selection of contractor is made based on the integrated score or Overall Evaluation Score of the decision alternative in prequalification as well as bid evaluation stages.
[The case-case-time-control study design].
Wang, Jing; Zhuo, Lin; Zhan, Siyan
2014-12-01
Although the 'self-matched case-only studies' (such as the case-cross-over or self-controlled case-series method) can control the time-invariant confounders (measured or unmeasured) through design of the study, however, they can not control those confounders that vary with time. A bidirectional case-crossover design can be used to adjust the exposure-time trends. In the areas of pharmaco-epidemiology, illness often influence the future use of medications, making a bidirectional study design problematic. Suissa's case-time-control design combines the case-crossover and the case-control design which could adjust for exposure-trend bias, but the control group may reintroduce selection bias, if the matching does not go well. We propose a "case-case-time-control" design which is an extension of the case-time-control design. However, rather than using a sample of external controls, we choose those future cases as controls for current cases to counter the bias that arising from temporal trends caused by exposure to the target of interest. In the end of this article we will discuss the strength and limitations of this design based on an applied example.
ERIC Educational Resources Information Center
Olson, Joanne K.; Bruxvoort, Crystal N.; Vande Haar, Andrea J.
2016-01-01
Little is known about how the content of a video case influences what preservice teachers learn about science teaching. This study was designed to determine the impact of two different video cases on preservice elementary teachers' conceptions of multiple aspects of effective science teaching, with one video selected to focus attention on the role…
Effects of the Case-Based Instruction Method on the Experience of Learning
ERIC Educational Resources Information Center
Amiri Farahani, Leila; Heidari, Tooba
2014-01-01
This semi-experimental study was conducted with twenty-seven midwifery students who were randomly allocated to either case-based instruction or lecture-based instruction groups. The selected subjects -- foetal intrapartum assessment, foetal antepartum assessment, ABO and Rh blood group system mismatch -- were presented in four ninety-minute…
Review of ecological-based risk management approaches used at five Army Superfund sites.
Poucher, Sherri L; Tracey, Gregory A; Johnson, Mark S; Haines, Laurie B
2012-04-01
Factors used in environmental remedial decision making concerning ecological risk are not well understood or necessarily consistent. Recent Records of Decision (RODs) for Army CERCLA sites were reviewed to select case studies where remedial management occurred in response to ecological risks. Thirty-four Army RODs were evaluated representing decisions promulgated between 1996 and 2004. Five were selected based on assessments that remedial actions were clearly linked to concern for ecological receptors. The Ecological Risk Assessment (ERA) approach and the subsequent risk management process were reviewed for each site. The case studies demonstrated that the ERA findings, as well as critical management decisions regarding interpretation of identified ecological risks, were determinants of remedial action objectives. Decisions regarding the selection of remedial alternatives were based on a set of criteria prescribed by Superfund requirements and guidance. Remedial alternative evaluations require protection of human health and the environment, but protective conditions were determined using different methods at each site. Examining the remedial management process for the 5 case study sites revealed that uncertainty in the risk assessment and decisions regarding appropriate spatial scales for both risk assessment and remediation were important factors influencing remedial action decisions. The case reviews also revealed that levels of documentation were variable from site to site. In the future, more detailed documentation of decision criteria and the development of criteria that consider the resilience of the site will result in more technically defensible ecological risk management. Copyright © 2011 SETAC.
Selection of examples in case-based computer-aided decision systems
Mazurowski, Maciej A.; Zurada, Jacek M.; Tourassi, Georgia D.
2013-01-01
Case-based computer-aided decision (CB-CAD) systems rely on a database of previously stored, known examples when classifying new, incoming queries. Such systems can be particularly useful since they do not need retraining every time a new example is deposited in the case base. The adaptive nature of case-based systems is well suited to the current trend of continuously expanding digital databases in the medical domain. To maintain efficiency, however, such systems need sophisticated strategies to effectively manage the available evidence database. In this paper, we discuss the general problem of building an evidence database by selecting the most useful examples to store while satisfying existing storage requirements. We evaluate three intelligent techniques for this purpose: genetic algorithm-based selection, greedy selection and random mutation hill climbing. These techniques are compared to a random selection strategy used as the baseline. The study is performed with a previously presented CB-CAD system applied for false positive reduction in screening mammograms. The experimental evaluation shows that when the development goal is to maximize the system’s diagnostic performance, the intelligent techniques are able to reduce the size of the evidence database to 37% of the original database by eliminating superfluous and/or detrimental examples while at the same time significantly improving the CAD system’s performance. Furthermore, if the case-base size is a main concern, the total number of examples stored in the system can be reduced to only 2–4% of the original database without a decrease in the diagnostic performance. Comparison of the techniques shows that random mutation hill climbing provides the best balance between the diagnostic performance and computational efficiency when building the evidence database of the CB-CAD system. PMID:18854606
Adhesive joint evaluation by ultrasonic interface and lamb waves
NASA Technical Reports Server (NTRS)
Rokhlin, S. I.
1986-01-01
Some results on the application of interface and Lamb waves for the study of curing of thin adhesive layers were summarized. In the case of thick substrates (thickness much more than the wave length) the interface waves can be used. In this case the experimental data can be inverted and the shear modulus of the adhesive film may be explicitly found based on the measured interface wave velocity. It is shown that interface waves can be used for the study of curing of structural adhesives as a function of different temperatures and other experimental conditions. The kinetics of curing was studied. In the case of thin substrates the wave phenomena are much more complicated. It is shown that for successful measurements proper selection of experimental conditions is very important. This can be done based on theoretical estimations. For correctly selected experimental conditions the Lamb waves may be a sensitive probe of adhesive bond quality and may be used or cure monitoring.
Tavani, Alessandra; La Vecchia, Carlo
2004-10-01
The literature from 1990 to 2003 on the relation between coffee, decaffeinated coffee, tea and colorectal cancer risk has been reviewed. For the relation with coffee, three cohort (517 total cases) and nine case-control studies (7555 cases) analysed colon cancer; three cohort (307 cases) and four case-control studies (2704 cases) rectal cancer; six case-control studies (854 cases) colorectal cancer. For colon cancer most case-control studies found risk estimates below unity; the results are less clear for cohort studies. No relation emerged for rectal cancer. A meta-analysis, including five cohort and twelve case-control studies, reported a pooled relative risk of 0.76 (significant). Any methodological artefact is unlikely to account for the consistent inverse association in different countries and settings. Plausible biological explanations include coffee-related reductions of cholesterol, bile acids and neutral sterol secretion in the colon; antimutagenic properties of selected coffee components; increased colonic motility. Decaffeinated coffee was not related to either colon or rectal cancer in three case-control studies. No overall association between tea and either colon or rectal cancer risk emerged in seven cohort (1756 total cases of colon, 759 of rectal and 60 of colorectal cancer) and 12 case-control studies (8058 cases of colon, 4865 of rectal, 604 of colorectal cancer).
Gu, Si-Ping; Zeng, Guo-Hua; You, Zhi-Yuan; Lu, Yi-Jin; Huang, Yun-Teng; Wang, Qing-Mao; He, Zhao-Hui
2015-12-01
Strict selection of patients for minimally invasive percutaneous nephrolithotomy could effectively improve the success rate of surgery. This study aimed to understand the required skills and the efficacy of mini-PCNL in the treatment of five types of upper ureteral calculi. Data collected after X-ray analysis and B mode ultrasound from 633 patients with upper ureteral and renal pelvis calculi who underwent B ultrasound-guided lithotomy was reviewed, including the following: type I, upper ureteral or renal pelvis calculi with moderate hydronephrosis (154 cases); type II, upper ureteral or renal pelvis calculi with severe hydronephrosis (157 cases); type III, upper ureteral or renal pelvis calculi without hydronephrosis (61 cases); type IV, renal pelvis calculi, one or two renal calyx calculi (206 cases); and type V, renal staghorn calculi (55 cases). Operations on 611 cases were successful. The treatment method for five patients was converted to open surgery. Twelve cases were treated by indwelling double-J tube retro-catheterization and extracorporeal shock wave lithotripsy. Five patients gave up the treatment. The rate of calculus clearance was 82.3 %, and the rate of residual calculus was 17.6 %. Selective renal artery embolization was performed in nine cases. Hydropneumothorax occurred in nine cases. No intestinal fistula occurred, and no patient had to undergo nephrectomy. The difficulty and the curative effect of the operation were different because the types of calculi varied. Selection of the procedure based on the different types of calculi could effectively improve the success rate of the procedure, reduce complications, and shorten the learning curve.
The PIG in sPrInG: evidence on letter grouping from the reading of buried words.
Humphreys, Glyn W; Mayall, Kate; Cooper, Adam C G
2003-12-01
We introduce a novel procedure for investigating factors that determine selective attention to letters in words. Participants were presented with words (in Experiments 1 and 3) and nonwords (in Experiment 2) that contained a buried word whose letters differed in color relative to the other letters present (e.g., pig, in spring). The strings were presented in single case or mixed case, keeping the letters of the buried words in one case (SpRiNg). The time in which the whole stimulus was named was shorter for same-case than for mixed-case strings (for spring: spring < SpRiNg). In contrast, the time in which buried words were named was shorter in mixed- than in same-case strings (for pig: spring > SpRiNg). Across items, the effects of case mixing were negatively correlated across the two tasks. The positive effect of case mixing for buried words also occurred irrespective of whether the whole string was a word or a nonword, and there were contributions from similarity of both letter size and case. The results suggest that case mixing can facilitate selective attention to letters, which is otherwise disrupted by size- and case-based grouping across letter strings. The study provides evidence for letter grouping using size and case information.
2016-09-01
iterations in that time for the student practitioners to work through. When possible, case studies will be selected from actual counter-radicalizations...justify participation in the learning 9 organization. Those cases will be evaluated on a case -by- case basis and the need to expand the CVE mission...interested within the learning organization. The National Fire Academy Executive Fire Officer Program applied research pre -course is an example of
Sugarcane Genotype Selection on Muck and Sand Soils in Florida — a Case for Dedicated Environments
USDA-ARS?s Scientific Manuscript database
Traditionally, the cooperative sugarcane breeding program at Canal Point, Florida has selected genotypes exclusively on muck soils in the early to middle stages of the program, resulting in the possibility that many genotypes adapted to sand soils are discarded. The objective of this study was to de...
Automatic Selection of Suitable Sentences for Language Learning Exercises
ERIC Educational Resources Information Center
Pilán, Ildikó; Volodina, Elena; Johansson, Richard
2013-01-01
In our study we investigated second and foreign language (L2) sentence readability, an area little explored so far in the case of several languages, including Swedish. The outcome of our research consists of two methods for sentence selection from native language corpora based on Natural Language Processing (NLP) and machine learning (ML)…
Developing Instructional Applications at the Secondary Level. The Computer as a Tool.
ERIC Educational Resources Information Center
McManus, Jack; And Others
Case studies are presented for seven Los Angeles area (California) high schools that worked with Pepperdine University in the IBM/ETS (International Business Machines/Educational Testing Service) Model Schools program, a project which provided training for selected secondary school teachers in the use of personal computers and selected software as…
A Case Study Analysis of Middle School Principals' Teacher Selection Criteria
ERIC Educational Resources Information Center
Woodburn, Jane Lai
2012-01-01
The hiring of middle school teachers to positively impact student achievement--is this a process of teacher selection or teacher attraction for schools, respectively, with low teacher turnover and schools with high teacher turnover? Since research indicates that the most important variable influencing student achievement is having a highly…
Museums and the Web 1999: Selected Papers from an International Conference.
ERIC Educational Resources Information Center
Bearman, David, Ed.; Trant, Jennifer, Ed.
Following an introduction by the editors entitled "Interactivity Comes of Age: Museums and World Wide Web at Five," this proceedings contains the following selected papers and case studies: "From the Mountains of the Moon to the Neon Paintbrush" (Peter Walsh); "Visiting a Museum Together: How To Share a Visit to a Virtual…
ERIC Educational Resources Information Center
Gelinas, Ulric J., Jr.; Rama, D. V.; Skelton, Terrance M.
1997-01-01
Profiles a writing-across-the-curriculum project in an accountancy program. Notes that the team's collaborative process produced three critical planning decisions: (1) establishing "fitness-for-use" for evaluating student communications; (2) selecting only those forms of communication used in accountancy; and (3) teaching only those…
ERIC Educational Resources Information Center
D'Allegro, Mary Lou; Zhou, Kai
2013-01-01
Peer selection based on the similarity of a couple of institutional parameters, by itself, is insufficient. Several other considerations, including clarity of purpose, alignment of institutional information to that purpose, identification of appropriate statistical procedures, review of preliminary peer sets, and the application of additional…
Clinical Case Studies in Psychoanalytic and Psychodynamic Treatment
Willemsen, Jochem; Della Rosa, Elena; Kegerreis, Sue
2017-01-01
This manuscript provides a review of the clinical case study within the field of psychoanalytic and psychodynamic treatment. The method has been contested for methodological reasons and because it would contribute to theoretical pluralism in the field. We summarize how the case study method is being applied in different schools of psychoanalysis, and we clarify the unique strengths of this method and areas for improvement. Finally, based on the literature and on our own experience with case study research, we come to formulate nine guidelines for future case study authors: (1) basic information to include, (2) clarification of the motivation to select a particular patient, (3) information about informed consent and disguise, (4) patient background and context of referral or self-referral, (5) patient's narrative, therapist's observations and interpretations, (6) interpretative heuristics, (7) reflexivity and counter-transference, (8) leaving room for interpretation, and (9) answering the research question, and comparison with other cases. PMID:28210235
Oon, Phei Phei
2010-04-01
This case study examines an integrative approach combining drama therapy and the behavioural skill "shaping", as offered to Gladys, a 5-year-old girl diagnosed with selective mutism. This study found that shaping, when implemented in the context of play, with play as the primary reinforcer, elicited from Gladys vocalization and eventually speech within a very short time. Her vocalizations allowed her to enter dramatic play, which in turn propelled spontaneous speech. This article looks at how the three elements of dramatherapy - the playspace, role-playing and dramatic projection - brought about therapeutic changes for Gladys. Aside from spontaneous speech, Gladys also developed positive self-esteem and a heightened sense of spontaneity. Subsequently, these two qualities helped her generalize her speech to new settings on her own. Gladys's newly harnessed spontaneity further helped her become more sociable and resilient.This study advances the possibility of integrating a behavioural skill with drama therapy for the therapeutic benefits of a child with an anxiety-related condition like selective mutism.
Jones, Jo; Jackson, Janet; Tudor, Terry; Bates, Margaret
2012-09-01
Strategies for enhancing environmental management are a key focus for the government in the UK. Using a manufacturing company from the construction sector as a case study, this paper evaluates selected interventionist techniques, including environmental teams, awareness raising and staff training to improve environmental performance. The study employed a range of methods including questionnaire surveys and audits of energy consumption and generation of waste to examine the outcomes of the selected techniques. The results suggest that initially environmental management was not a focus for either the employees or the company. However, as a result of employing the techniques, the company was able to reduce energy consumption, increase recycling rates and achieve costs savings in excess of £132,000.
Agent-Based vs. Equation-based Epidemiological Models:A Model Selection Case Study
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sukumar, Sreenivas R; Nutaro, James J
This paper is motivated by the need to design model validation strategies for epidemiological disease-spread models. We consider both agent-based and equation-based models of pandemic disease spread and study the nuances and complexities one has to consider from the perspective of model validation. For this purpose, we instantiate an equation based model and an agent based model of the 1918 Spanish flu and we leverage data published in the literature for our case- study. We present our observations from the perspective of each implementation and discuss the application of model-selection criteria to compare the risk in choosing one modeling paradigmmore » to another. We conclude with a discussion of our experience and document future ideas for a model validation framework.« less
ERIC Educational Resources Information Center
Jay, Sandy
2011-01-01
This paper describes a qualitative case study designed to investigate research-based practices as a contemporary phenomenon within the real-life context of schools. Selected first grade teacher perceptions of research based practices and sustainability of research-based practices in rural, low-income schools that are no longer receiving funding…
Creativity in the Era of Social Networking: A Case Study at Tertiary Education in the Greek Context
ERIC Educational Resources Information Center
Theodotou, Evgenia; Papastathopoulos, Avraam
2015-01-01
This paper investigates the utilization of a social network tool in order to promote creativity in higher education. Buddypress was selected as a social network tool and de Bono's "6 thinking hats" as a creativity strategy. The participants were 17 undergraduate students from a case study in a University in Greece in the field of social…
ERIC Educational Resources Information Center
Provasi, Giancarlo; Squazzoni, Flaminio; Tosio, Beatrice
2012-01-01
This paper looks at eight comparative case-studies on academic entrepreneurs in life sciences conducted in Europe in 2008. The interviewees were selected from the KEINS database that lists all academic inventors from Italy, France, Sweden and the Netherlands who have one or more patent applications registered at the European Patent Office,…
ERIC Educational Resources Information Center
Dutcher, Nadine
This paper discusses the question of whether, in a multilingual society, the child's first or second language is best as a language of instruction in primary school. Reviewing eight case studies from seven countries in which initial primary schooling was given either in the second or first language, the discussion compares achievement in reading…
ERIC Educational Resources Information Center
Neely, Pat; Tucker, Jan
2013-01-01
Purpose: Simulations are designed as activities which imitate real world scenarios and are often used to teach and enhance skill building. The purpose of this case study is to examine the decision making process and outcomes of a faculty committee tasked with examining simulations in the marketplace to determine if the simulations could be used as…
ERIC Educational Resources Information Center
Hagen, Lisa J.
2012-01-01
A case-study was designed to assess the extent of change at a selected Florida community college that transformed into a state college. The purpose of the investigation was to explore how the transformation influenced institutional culture, mission, and identity based on the perceptions of faculty members and administrators. Data collection…
ERIC Educational Resources Information Center
Raditloaneng, Wapula Nelly
2009-01-01
The purpose of this paper is to illuminate that acquisition of knowledge, positive attitudes, skills and identity formation are by-products of primary socialisation and secondary interaction with people and institutions from all walks of family life, environmental experiences, and lifestyles. Based on the first phase of a qualitative case study on…
Stochastic model search with binary outcomes for genome-wide association studies.
Russu, Alberto; Malovini, Alberto; Puca, Annibale A; Bellazzi, Riccardo
2012-06-01
The spread of case-control genome-wide association studies (GWASs) has stimulated the development of new variable selection methods and predictive models. We introduce a novel Bayesian model search algorithm, Binary Outcome Stochastic Search (BOSS), which addresses the model selection problem when the number of predictors far exceeds the number of binary responses. Our method is based on a latent variable model that links the observed outcomes to the underlying genetic variables. A Markov Chain Monte Carlo approach is used for model search and to evaluate the posterior probability of each predictor. BOSS is compared with three established methods (stepwise regression, logistic lasso, and elastic net) in a simulated benchmark. Two real case studies are also investigated: a GWAS on the genetic bases of longevity, and the type 2 diabetes study from the Wellcome Trust Case Control Consortium. Simulations show that BOSS achieves higher precisions than the reference methods while preserving good recall rates. In both experimental studies, BOSS successfully detects genetic polymorphisms previously reported to be associated with the analyzed phenotypes. BOSS outperforms the other methods in terms of F-measure on simulated data. In the two real studies, BOSS successfully detects biologically relevant features, some of which are missed by univariate analysis and the three reference techniques. The proposed algorithm is an advance in the methodology for model selection with a large number of features. Our simulated and experimental results showed that BOSS proves effective in detecting relevant markers while providing a parsimonious model.
Terra, Sandra M
2007-01-01
This research seeks to determine whether there is adequate evidence-based justification for selection of one acute care case management model over another. Acute Inpatient Hospital. This article presents a systematic review of published case management literature, resulting in classification specific to terms of level of evidence. This review examines the best available evidence in an effort to select an acute care case management model. Although no single case management model can be identified as preferred, it is clear that adequate evidence-based literature exists to acknowledge key factors driving the acute care model and to form a foundation for the efficacy of hospital case management practice. Although no single case management model can be identified as preferred, this systematic review demonstrates that adequate evidence-based literature exists to acknowledge key factors driving the acute care model and forming a foundation for the efficacy of hospital case management practice. Distinctive aspects of case management frameworks can be used to guide the development of an acute care case management model. The study illustrates: * The effectiveness of case management when there is direct patient contact by the case manager regardless of disease condition: not only does the quality of care increase but also length of stay (LOS) decreases, care is defragmented, and both patient and physician satisfaction can increase. * The preferred case management models result in measurable outcomes that can directly relate to, and demonstrate alignment with, organizational strategy. * Acute care management programs reduce cost and LOS, and improve outcomes. * An integrated case management program that includes social workers, as well as nursing, is the most effective acute care management model. * The successful case management model will recognize physicians, as well as patients, as valued customers with whom partnership can positively affect financial outcomes in terms of reduction in LOS, improvement in quality, and delivery of care.
Kyriakis, Efstathios; Psomopoulos, Constantinos; Kokkotis, Panagiotis; Bourtsalas, Athanasios; Themelis, Nikolaos
2017-06-23
This study attempts the development of an algorithm in order to present a step by step selection method for the location and the size of a waste-to-energy facility targeting the maximum output energy, also considering the basic obstacle which is in many cases, the gate fee. Various parameters identified and evaluated in order to formulate the proposed decision making method in the form of an algorithm. The principle simulation input is the amount of municipal solid wastes (MSW) available for incineration and along with its net calorific value are the most important factors for the feasibility of the plant. Moreover, the research is focused both on the parameters that could increase the energy production and those that affect the R1 energy efficiency factor. Estimation of the final gate fee is achieved through the economic analysis of the entire project by investigating both expenses and revenues which are expected according to the selected site and outputs of the facility. In this point, a number of commonly revenue methods were included in the algorithm. The developed algorithm has been validated using three case studies in Greece-Athens, Thessaloniki, and Central Greece, where the cities of Larisa and Volos have been selected for the application of the proposed decision making tool. These case studies were selected based on a previous publication made by two of the authors, in which these areas where examined. Results reveal that the development of a «solid» methodological approach in selecting the site and the size of waste-to-energy (WtE) facility can be feasible. However, the maximization of the energy efficiency factor R1 requires high utilization factors while the minimization of the final gate fee requires high R1 and high metals recovery from the bottom ash as well as economic exploitation of recovered raw materials if any.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Rada, E.C., E-mail: Elena.Rada@ing.unitn.it; Ragazzi, M.; Fedrizzi, P.
Highlights: ► As an appropriate solution for MSW management in developed and transient countries. ► As an option to increase the efficiency of MSW selective collection. ► As an opportunity to integrate MSW management needs and services inventories. ► As a tool to develop Urban Mining actions. - Abstract: Municipal solid waste management is a multidisciplinary activity that includes generation, source separation, storage, collection, transfer and transport, processing and recovery, and, last but not least, disposal. The optimization of waste collection, through source separation, is compulsory where a landfill based management must be overcome. In this paper, a few aspectsmore » related to the implementation of a Web-GIS based system are analyzed. This approach is critically analyzed referring to the experience of two Italian case studies and two additional extra-European case studies. The first case is one of the best examples of selective collection optimization in Italy. The obtained efficiency is very high: 80% of waste is source separated for recycling purposes. In the second reference case, the local administration is going to be faced with the optimization of waste collection through Web-GIS oriented technologies for the first time. The starting scenario is far from an optimized management of municipal solid waste. The last two case studies concern pilot experiences in China and Malaysia. Each step of the Web-GIS oriented strategy is comparatively discussed referring to typical scenarios of developed and transient economies. The main result is that transient economies are ready to move toward Web oriented tools for MSW management, but this opportunity is not yet well exploited in the sector.« less
Genetic study of intracranial aneurysms.
Yan, Junxia; Hitomi, Toshiaki; Takenaka, Katsunobu; Kato, Masayasu; Kobayashi, Hatasu; Okuda, Hiroko; Harada, Kouji H; Koizumi, Akio
2015-03-01
Rupture of intracranial aneurysms (IAs) causes subarachnoid hemorrhage, leading to immediate death or severe disability. Identification of the genetic factors involved is critical for disease prevention and treatment. We aimed to identify the susceptibility genes for IAs. Exome sequencing was performed in 12 families with histories of multiple cases of IA (number of cases per family ≥3), with a total of 42 cases. Various filtering strategies were used to select the candidate variants. Replicate association studies of several candidate variants were performed in probands of 24 additional IA families and 426 sporadic IA cases. Functional analysis for the mutations was conducted. After sequencing and filtering, 78 variants were selected for the following reasons: allele frequencies of variants in 42 patients was significantly (P<0.05) larger than expected; variants were completely shared by all patients with IA within ≥1 family; variants predicted damage to the structure or function of the protein by PolyPhen-2 (Polymorphism Phenotyping V2) and SIFT (Sorting Intolerance From Tolerant). We selected 10 variants from 9 genes (GPR63, ADAMST15, MLL2, IL10RA, PAFAH2, THBD, IL11RA, FILIP1L, and ZNF222) to form 78 candidate variants by considering commonness in families, known disease genes, or ontology association with angiogenesis. Replicate association studies revealed that only p.E133Q in ADAMTS15 was aggregated in the familial IA cases (odds ratio, 5.96; 95% confidence interval, 2.40-14.82; P=0.0001; significant after the Bonferroni correction [P=0.05/78=0.0006]). Silencing ADAMTS15 and overexpression of ADAMTS15 p.E133Q accelerated endothelial cell migration, suggesting that ADAMTS15 may have antiangiogenic activity. ADAMTS15 is a candidate gene for IAs. © 2015 American Heart Association, Inc.
NASA Technical Reports Server (NTRS)
1975-01-01
This case study and generalization quantify benefits made possible through improved weather forecasting resulting from the integration of SEASAT data into local weather forecasts. The major source of avoidable economic losses to shipping from inadequate weather forecasting data is shown to be dependent on local precipitation forecasting. The ports of Philadelphia and Boston were selected for study.
Application Of Decision Tree Approach To Student Selection Model- A Case Study
NASA Astrophysics Data System (ADS)
Harwati; Sudiya, Amby
2016-01-01
The main purpose of the institution is to provide quality education to the students and to improve the quality of managerial decisions. One of the ways to improve the quality of students is to arrange the selection of new students with a more selective. This research takes the case in the selection of new students at Islamic University of Indonesia, Yogyakarta, Indonesia. One of the university's selection is through filtering administrative selection based on the records of prospective students at the high school without paper testing. Currently, that kind of selection does not yet has a standard model and criteria. Selection is only done by comparing candidate application file, so the subjectivity of assessment is very possible to happen because of the lack standard criteria that can differentiate the quality of students from one another. By applying data mining techniques classification, can be built a model selection for new students which includes criteria to certain standards such as the area of origin, the status of the school, the average value and so on. These criteria are determined by using rules that appear based on the classification of the academic achievement (GPA) of the students in previous years who entered the university through the same way. The decision tree method with C4.5 algorithm is used here. The results show that students are given priority for admission is that meet the following criteria: came from the island of Java, public school, majoring in science, an average value above 75, and have at least one achievement during their study in high school.
Jostins, Luke; Levine, Adam P; Barrett, Jeffrey C
2013-01-01
A central focus of complex disease genetics after genome-wide association studies (GWAS) is to identify low frequency and rare risk variants, which may account for an important fraction of disease heritability unexplained by GWAS. A profusion of studies using next-generation sequencing are seeking such risk alleles. We describe how already-known complex trait loci (largely from GWAS) can be used to guide the design of these new studies by selecting cases, controls, or families who are most likely to harbor undiscovered risk alleles. We show that genetic risk prediction can select unrelated cases from large cohorts who are enriched for unknown risk factors, or multiply-affected families that are more likely to harbor high-penetrance risk alleles. We derive the frequency of an undiscovered risk allele in selected cases and controls, and show how this relates to the variance explained by the risk score, the disease prevalence and the population frequency of the risk allele. We also describe a new method for informing the design of sequencing studies using genetic risk prediction in large partially-genotyped families using an extension of the Inside-Outside algorithm for inference on trees. We explore several study design scenarios using both simulated and real data, and show that in many cases genetic risk prediction can provide significant increases in power to detect low-frequency and rare risk alleles. The same approach can also be used to aid discovery of non-genetic risk factors, suggesting possible future utility of genetic risk prediction in conventional epidemiology. Software implementing the methods in this paper is available in the R package Mangrove.
Tang, K T; Lin, C H; Chen, H H; Chen, Y H; Chen, D Y
2016-02-01
A four-fold increase of suicide mortality has been demonstrated in systemic lupus erythematosus (SLE) patients. Prior studies showed that the most common method of suicide attempts in SLE patients involves drug overdose. Therefore, we conducted a nationwide population-based case-control study to elucidate factors associated with drug overdose as suicide attempt in SLE patients. This study was based on the National Health Insurance Research Database in Taiwan. We identified all SLE patients from January 1, 2000 to December 31, 2010. Patients who had suicidal drug overdose (SDO) were selected as cases while age- and gender-matched patients who did not have SDO were selected as controls. The incidence rate of SDO in SLE patients was 291 cases per 100,000 person-years, higher than that in the general population (160 cases per 100,000 person-years). In a multivariate logistic regression analysis, we observed that SDO was associated with psychiatric disorders such as depressive disorders (odds ratio: 8.36, 95% confidence interval (CI): 5.60-12.48) and insomnia (odds ratio: 2.71, 95% CI: 1.73-4.25), and lower monthly income (odds ratios: 2.74 to 3.50) in SLE patients. SDO is associated with psychiatric disorders such as depressive disorders and insomnia, and lower monthly income in SLE patients. © The Author(s) 2015.
Kim, Soo Hee; Choi, Yoomi; Jeong, Hae Yeon; Lee, Kyoungbun; Chae, Ji Youn; Moon, Kyung Chul
2011-09-01
Xp11.2 translocation renal cell carcinoma (RCC) is a rare subtype of RCC predominantly reported in young patients. It results from gene fusions between the transcription factor E3 (TFE3) gene, which is located on chromosome Xp11.2, and various fusion partners. Recently, a dual color, break-apart fluorescence in situ hybridization (FISH) assay to detect Xp11.2 translocation was reported. We performed this study to evaluate the usefulness of the FISH assay in the diagnosis of Xp11.2 translocation RCC using a commercially available TFE3 break-apart probe. We immunohistochemically analyzed TFE3 nuclear expression in 809 cases of RCCs using 14 tissue microarray blocks and selected nine cases those showed moderate to strong positive nuclear immunoreactivity for TFE3. The extent of TFE3 nuclear expression was variable. The TFE3 FISH assay was performed in these 9 selected cases and 44 negative control cases. Only four out of nine selected cases showed the TFE3 break-apart signal. TFE3 FISH-positive cases mainly showed diffuse and strong TFE3 immunopositivity, but one case revealed focal and moderate TFE3 staining. On the contrary, TFE3 FISH-negative cases mainly revealed focal and moderate TFE3 immunoreactivity, however, one FISH-negative case revealed diffuse and strong TFE3 nuclear immunopositivity. All negative control cases revealed normal TFE3 FISH results. Our results reveal that TFE3 immunohistochemistry can show false-positive results, and that the TFE3 break-apart FISH assay is a useful complementary method for confirming the diagnosis of Xp11.2 translocation RCC.
Deconstructing the smoking-preeclampsia paradox through a counterfactual framework.
Luque-Fernandez, Miguel Angel; Zoega, Helga; Valdimarsdottir, Unnur; Williams, Michelle A
2016-06-01
Although smoking during pregnancy may lead to many adverse outcomes, numerous studies have reported a paradoxical inverse association between maternal cigarette smoking during pregnancy and preeclampsia. Using a counterfactual framework we aimed to explore the structure of this paradox as being a consequence of selection bias. Using a case-control study nested in the Icelandic Birth Registry (1309 women), we show how this selection bias can be explored and corrected for. Cases were defined as any case of pregnancy induced hypertension or preeclampsia occurring after 20 weeks' gestation and controls as normotensive mothers who gave birth in the same year. First, we used directed acyclic graphs to illustrate the common bias structure. Second, we used classical logistic regression and mediation analytic methods for dichotomous outcomes to explore the structure of the bias. Lastly, we performed both deterministic and probabilistic sensitivity analysis to estimate the amount of bias due to an uncontrolled confounder and corrected for it. The biased effect of smoking was estimated to reduce the odds of preeclampsia by 28 % (OR 0.72, 95 %CI 0.52, 0.99) and after stratification by gestational age at delivery (<37 vs. ≥37 gestation weeks) by 75 % (OR 0.25, 95 %CI 0.10, 0.68). In a mediation analysis, the natural indirect effect showed and OR > 1, revealing the structure of the paradox. The bias-adjusted estimation of the smoking effect on preeclampsia showed an OR of 1.22 (95 %CI 0.41, 6.53). The smoking-preeclampsia paradox appears to be an example of (1) selection bias most likely caused by studying cases prevalent at birth rather than all incident cases from conception in a pregnancy cohort, (2) omitting important confounders associated with both smoking and preeclampsia (preventing the outcome to develop) and (3) controlling for a collider (gestation weeks at delivery). Future studies need to consider these aspects when studying and interpreting the association between smoking and pregnancy outcomes.
Considerations for conducting epidemiologic case-control studies of cancer in developing countries.
Brinton, L A; Herrero, R; Brenes, M; Montalván, P; de la Guardia, M E; Avila, A; Domínguez, I L; Basurto, E; Reeves, W C
1991-01-01
The challenges involved in conducting epidemiologic studies of cancer in developing countries can be and often are unique. This article reports on our experience in performing a case-control study of invasive cervical cancer in four Latin American countries (Columbia, Costa Rica, Mexico, and Panama), the summary medical results of which have been published in a previous issue of this journal (1). The study involved a number of principal activities--mainly selecting, conducting interviews with, and obtaining appropriate biologic specimens from 759 cervical cancer patients, 1,467 matched female controls, and 689 male sex partners of monogamous female subjects. This presentation provides an overview of the planning and methods used to select the subjects, conduct the survey work, and obtain complete and effectively unbiased data. It also points out some of the important advantages and disadvantages of working in developing areas similar to those serving as locales for this study.
Optical Sensor/Actuator Locations for Active Structural Acoustic Control
NASA Technical Reports Server (NTRS)
Padula, Sharon L.; Palumbo, Daniel L.; Kincaid, Rex K.
1998-01-01
Researchers at NASA Langley Research Center have extensive experience using active structural acoustic control (ASAC) for aircraft interior noise reduction. One aspect of ASAC involves the selection of optimum locations for microphone sensors and force actuators. This paper explains the importance of sensor/actuator selection, reviews optimization techniques, and summarizes experimental and numerical results. Three combinatorial optimization problems are described. Two involve the determination of the number and position of piezoelectric actuators, and the other involves the determination of the number and location of the sensors. For each case, a solution method is suggested, and typical results are examined. The first case, a simplified problem with simulated data, is used to illustrate the method. The second and third cases are more representative of the potential of the method and use measured data. The three case studies and laboratory test results establish the usefulness of the numerical methods.
1985-02-15
utilizes a cathode contained within a membrane module to selectively precipitate trivalent chromium and other cations from the plating solution...Cadmium Plating at Lockheed, Case No. 6 5-6 5.4.2 LICON Chromium Recovery at Pensacola NARF, Case No. 9 5-7 iii CONTENTS (continued) Page 5.4.3 LICON... Chromium Recovery at Charleston NYS, Case No. 12 5-9 5.4.4 Innovative Chromium Plating at Pensacola NARF, Case No. 10 5-10 5.4.5 Steam Condensate
Associated factors with attention deficit hyperactivity disorder (ADHD): a case-control study.
Malek, Ayyoub; Amiri, Shahrokh; Sadegfard, Majid; Abdi, Salman; Amini, Saeedeh
2012-09-01
The current study attempted to investigate factors associated with attention deficit hyperactivity disorder (ADHD) in children without co-morbidities. In this case-control study, 164 ADHD children who attended the Child and Adolescent Psychiatric Clinics of Tabriz University of Medical Sciences, Iran were compared with 166 normal children selected in a random-cluster method from primary and secondary schools. Clinical interviews based on DSM-IV-TR using K-SADS were used to diagnose ADHD cases and to select the control group. Participants were matched for age. We used chi-square and binary logistic regression for data analysis. Among the associated factors with ADHD were gender and maternal employment. Boys (OR 0.54; 95% confidence interval: 0.34 - 0.86) and those children with working mothers (OR 0.16: 95% confidence interval: 0.06 - 0.86) suffered more from ADHD. The birth season, family size, birth order, and parental kinship were not among risk factors for ADHD. The results of the study show that maternal employment and male gender are among the associated risk factors for ADHD.
Swayne, Seanna L; Brisson, Brigitte; Weese, J Scott; Sears, William
2012-09-01
This pilot study describes the effect of intraoperative peritoneal lavage (IOPL) on bacterial counts and outcome in clinical cases of septic peritonitis. Intraoperative samples were cultured before and after IOPL. Thirty-three dogs with presumed septic peritonitis on the basis of cytology were managed surgically during the study period. Positive pre-lavage bacterial cultures were found in 14 cases, 13 of which were a result of intestinal leakage. The post-lavage cultures showed fewer isolates in 9 cases and in 1 case became negative. The number of dogs with a decrease in the concentration of bacteria cultured from pre-lavage to post-lavage samples was not statistically significant. There was no significant effect of the change in pre- to post-lavage culture, single versus multiple types of bacteria, selection of an appropriate empiric antimicrobial on survival or the need for subsequent surgery. This pilot study describes the effect of intraoperative peritoneal lavage (IOPL) on bacterial counts and outcome in clinical cases of septic peritonitis. Intraoperative samples were cultured before and after IOPL. Thirty-three dogs with presumed septic peritonitis on the basis of cytology were managed surgically during the study period. Positive pre-lavage bacterial cultures were found in 14 cases, 13 of which were a result of intestinal leakage. The post-lavage cultures showed fewer isolates in 9 cases and in 1 case became negative. The number of dogs with a decrease in the concentration of bacteria cultured from pre-lavage to post-lavage samples was not statistically significant. There was no significant effect of the change in pre- to post-lavage culture, single versus multiple types of bacteria, selection of an appropriate empiric antimicrobial on survival or the need for subsequent surgery.
Anderson, Timothy; Strupp, Hans H
2015-01-01
This qualitative study systematically compared cases treated by the same therapist in order to understand the group comparison findings of a larger study on training of experienced therapists (the "Vanderbilt II" psychotherapy project). The therapist, Dr C., was selected based on the therapist's overall treatment successes. His two patients were selected based on their outcomes and the relative training cohort from which they were drawn: a case with successful outcome from the pre-training cohort and a case of negligible improvement from the post-training cohort. Dr C. demonstrated a variety of interpersonal skills throughout his pre-training case, though there was also poor interpersonal process throughout. However, in the second case he had considerable difficulty in adapting his typical therapeutic approach to the requirements of the time-limited dynamic psychotherapy (TLDP) manual, even while appearing to work hard to find ways to use the manual. Dr C.'s spontaneity, and his unique set of interpersonal skills may enhanced his initial rapport and alliance building with clients and yet may not have interfaced well with TLDP. His unique interpersonal skills also may have contributed to problems of interpersonal process. Future research may benefit from examining the interaction of between therapist interpersonal skills and the implementation of the treatment manual.
Prevalence of Lynch syndrome in a Middle Eastern population with colorectal cancer.
Siraj, Abdul K; Prabhakaran, Sarita; Bavi, Prashant; Bu, Rong; Beg, Shaham; Hazmi, Mohsen Al; Al-Rasheed, Maha; Al-Assiri, Mohammed; Sairafi, Rami; Al-Dayel, Fouad; Al-Sanea, Nasser; Uddin, Shahab; Al-Kuraya, Khawla S
2015-06-01
Lynch syndrome (LS; hereditary nonpolyposis colorectal cancer) is a common cause of hereditary colorectal cancer (CRC). CRC is the most common cancer diagnosed among males in Saudi Arabia but to the authors' knowledge there is a lack of data regarding the prevalence of LS in patients with CRC. There currently are no clear guidelines for the selection criteria for these patients to screen for LS. A comprehensive molecular characterization was performed in a cohort of 807 CRC cases by immunohistochemical and microsatellite analysis using polymerase chain reaction. BRAF mutation screening, high CpG island methylator phenotype, and analysis for germline mutations were performed in 425 CRC samples. These were all high microsatellite instability (MSI-H) samples (91 cases), all low MSI samples (143 cases), and selected cases from the microsatellite stable group (191 cases) that met revised Bethesda guidelines. Polymerase chain reaction identified 91 MSI-H cases (11.3%) and sequencing revealed mismatch repair germline mutations in 8 CRC cases only. Of the total of 807 CRC cases, these 8 cases (0.99%) were MSI-H, met the revised Bethesda guidelines, and did not harbor BRAF mutations. The results of the current study confirmed cases of LS in approximately 1.0% of CRC samples and reflects the efficacy of screening among MSI-H cases that lack BRAF mutations. This comprehensive study from Saudi Arabia will help in implementing a universal screening/reflex testing strategy in a clinical setting in Saudi Arabia and in conducting a national screening program that benefits both patients and their relatives. © 2015 American Cancer Society.
Systematic review of the methodological and reporting quality of case series in surgery.
Agha, R A; Fowler, A J; Lee, S-Y; Gundogan, B; Whitehurst, K; Sagoo, H K; Jeong, K J L; Altman, D G; Orgill, D P
2016-09-01
Case series are an important and common study type. No guideline exists for reporting case series and there is evidence of key data being missed from such reports. The first step in the process of developing a methodologically sound reporting guideline is a systematic review of literature relevant to the reporting deficiencies of case series. A systematic review of methodological and reporting quality in surgical case series was performed. The electronic search strategy was developed by an information specialist and included MEDLINE, Embase, Cochrane Methods Register, Science Citation Index and Conference Proceedings Citation index, from the start of indexing to 5 November 2014. Independent screening, eligibility assessments and data extraction were performed. Included articles were then analysed for five areas of deficiency: failure to use standardized definitions, missing or selective data (including the omission of whole cases or important variables), transparency or incomplete reporting, whether alternative study designs were considered, and other issues. Database searching identified 2205 records. Through the process of screening and eligibility assessments, 92 articles met inclusion criteria. Frequencies of methodological and reporting issues identified were: failure to use standardized definitions (57 per cent), missing or selective data (66 per cent), transparency or incomplete reporting (70 per cent), whether alternative study designs were considered (11 per cent) and other issues (52 per cent). The methodological and reporting quality of surgical case series needs improvement. The data indicate that evidence-based guidelines for the conduct and reporting of case series may be useful. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.
Edwards, G P
1997-10-01
Seasonal diet selection in the yellow-bellied marmot (Marmota flaviventris) was studied at two sites in Montana during 1991 and 1992. A linear programming model of optimal diet selection successfully predicted the composition of observed diets (monocot versus dicot) in eight out of ten cases early in the active season (April-June). During this period, adult, yearling and juvenile marmots selected diets consistent with the predicted goal of energy maximisation. However, late in the active season (July-August), the model predicted the diet composition in only one out of six cases. In all six late-season determinations, the model underestimated the amount of monocot in the diet. Possible reasons why the model failed to reliably predict diet composition late in the active season are discussed.
High hunting pressure selects for earlier birth date: Wild boar as a case study
Gamelon, M.; Besnard, A.; Gaillard, J.-M.; Servanty, S.; Baubet, E.; Brandt, S.; Gimenez, O.
2011-01-01
Exploitation by humans affects the size and structure of populations. This has evolutionary and demographic consequences that have typically being studied independent of one another. We here applied a framework recently developed applying quantitative tools from population ecology and selection gradient analysis to quantify the selection on a quantitative trait-birth date-through its association with multiple fitness components. From the long-term monitoring (22 years) of a wild boar (Sus scrofa scrofa) population subject to markedly increasing hunting pressure, we found that birth dates have advanced by up to 12 days throughout the study period. During the period of low hunting pressure, there was no detectable selection. However, during the period of high hunting pressure, the selection gradient linking breeding probability in the first year of life to birth date was negative, supporting current life-history theory predicting selection for early births to reproduce within the first year of life with increasing adult mortality. ?? 2011 The Author(s). Evolution?? 2011 The Society for the Study of Evolution..
A case-control study of Yersinia enterocolitica infections in Auckland.
Satterthwaite, P; Pritchard, K; Floyd, D; Law, B
1999-10-01
To identify major risk factors for Yersinia enterocolitica (YE) and identify measures to reduce YE infections. A prospective case control study, group age matched, using 186 cases of YE identified by community pathology laboratories and 379 randomly selected controls. Conducted between April 1995 and June 1996 in Auckland, New Zealand. Face-to-face interviews used a standardised questionnaire examining exposures to factors potentially associated with YE infections including untreated water, unreticulated sewerage, consumption of selected foods, selected food handling practices and socio-demographic factors. Multivariate logistic regression was used to calculate adjusted odds ratios for the potential risk factors. Population attributable risk (PAR) was calculated for significant exposures. Having more than two people living in the home was more common among cases than controls (OR = 2.2). Town supply water (OR = 0.2), reticulated sewerage (OR = 0.34) and looking after a young child (OR = 0.51) were significantly less common. Of the meats, only pork (OR = 1.34) had a higher consumption rate, while bacon (OR = 0.75) and smallgoods (OR = 0.73) were consumed less frequently by cases than controls. Eating food from a sandwich bar was more frequent among cases (OR = 1.18). Fruit and vegetable consumption was marginally less (OR = 0.98). The population attributable risk of these factors was 0.89, implying that 89% of YE would be eliminated if adverse exposures were removed. The risk of YE illness is increased by contact with untreated water, unreticulated sewerage and consumption of pork. Investigation of non-town water supply, informal sewerage systems and methods of preparation and consumption of pork are recommended to determine how YE enters the human food chain.
Individualized Instruction in Great Britain: A Survey and a Case Study.
ERIC Educational Resources Information Center
Roach, D. Keith; Hammond, Roger A.
1981-01-01
Presents results of a selective survey of schools using individualized instruction (II) in Great Britain and a detailed description of a particular II self-study zoology course at University College, Cardiff. (CS)
Qualitative case study methodology in nursing research: an integrative review.
Anthony, Susan; Jack, Susan
2009-06-01
This paper is a report of an integrative review conducted to critically analyse the contemporary use of qualitative case study methodology in nursing research. Increasing complexity in health care and increasing use of case study in nursing research support the need for current examination of this methodology. In 2007, a search for case study research (published 2005-2007) indexed in the CINAHL, MEDLINE, EMBASE, PsychINFO, Sociological Abstracts and SCOPUS databases was conducted. A sample of 42 case study research papers met the inclusion criteria. Whittemore and Knafl's integrative review method guided the analysis. Confusion exists about the name, nature and use of case study. This methodology, including terminology and concepts, is often invisible in qualitative study titles and abstracts. Case study is an exclusive methodology and an adjunct to exploring particular aspects of phenomena under investigation in larger or mixed-methods studies. A high quality of case study exists in nursing research. Judicious selection and diligent application of literature review methods promote the development of nursing science. Case study is becoming entrenched in the nursing research lexicon as a well-accepted methodology for studying phenomena in health and social care, and its growing use warrants continued appraisal to promote nursing knowledge development. Attention to all case study elements, process and publication is important in promoting authenticity, methodological quality and visibility.
Noncredit Continuing Education: Who Does what for Whom...and Why?
ERIC Educational Resources Information Center
Long, Norma R.
1988-01-01
A case study illustrates the need to examine criteria used to select noncredit continuing education offerings. In this case, the physics faculty protested that the offering "Fundamentals of Astrology" was inappropriate as a university noncredit course. A survey of 77 continuing education divisions revealed how course offering choices are made. (CH)
Never Going Back: An Examination of Financial Health at Selected Private South Carolina Universities
ERIC Educational Resources Information Center
Armstrong, David C., Sr.
2014-01-01
This case study examined the leadership styles and overall financial health of the three South Carolina Baptist Convention universities. Each university share a similar story of financial exigency prior to the current president's arrival. Each institution has increased enrollment, endowment, and facilities over the last decade. This case study…
Prestige-Oriented Market Entry Strategy: The Case of Australian Universities
ERIC Educational Resources Information Center
Tayar, Mark; Jack, Robert
2013-01-01
Through an exploratory case study of four Australian universities this article finds that foreign market entry strategies are shaped by prestige-seeking motivations and a culture of risk aversion. From the market selection, entry mode and higher education literature, a conceptual model, embedded with four propositions, is presented. The model sees…
Making Total Quality Management + Just-in-Time Manufacturing Work.
ERIC Educational Resources Information Center
Waldrop, Phillip S.; Scott, Thomas E.
2000-01-01
In one case study, teamwork was implemented in mainstream production; in a second, teamwork was applied to an ad hoc project. The cases show that process technologies and management strategies such as just-in-time are not enough; selection of the appropriate mix of individuals with complementary traits is crucial. (SK)
Gifted and Talented Education: A National Test Case in Peoria.
ERIC Educational Resources Information Center
Fetterman, David M.
1986-01-01
This article presents a study of a program in Peoria, Illinois, for the gifted and talented that serves as a national test case for gifted education and minority enrollment. It was concluded that referral, identification, and selection were appropriate for the program model but that inequalities resulted from socioeconomic variables. (Author/LMO)
A close look at beam aborts with rise times less than 40 ms from the years 2014-2016. Case studies.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Drees, A.
2016-09-14
In an effort to understand the risks of operating RHIC with an additional delay of 40 ms in the abort system, all beam aborts triggered by loss monitors at store from the years 2014, 2015 and 2016 were analyzed; and particularly fast cases, selected. The results were presented at the RHIC retreat on Jul 29, 2016. All beam aborts at injection, during the ramp and at flattop but before the “ev-lumi” event were ignored since the additional delay of 40 ms is proposed for operation at store only. Many (but not all) of the 15 studied cases are of nomore » concern. Cases with high damage potential are rare - but not rare enough. In order to make an added 40 ms during physics store conditions as safe as reasonably possible, additional permit inputs such as 10 Hz BF power supplies, RF storage cavities, power supply error states or BPMs, in addition to significantly reduced loss monitors (LM) thresholds for selected LM should be commissioned.« less
Avula, Shivaram; Pettorini, Benedetta; Abernethy, Laurence; Pizer, Barry; Williams, Dawn; Mallucci, Conor
2013-10-01
The purpose of this study is to compare the surgical and imaging outcome in children who underwent brain tumour surgery with intention of complete tumour resection, prior to and following the start of intra-operative MRI (ioMRI) service. ioMRI service for brain tumour resection commenced in October 2009. A cohort of patients operated between June 2007 and September 2009 with a pre-surgical intention of complete tumour resection were selected (Group A). A similar number of consecutive cases were selected from a prospective database of patients undergoing ioMRI (Group B). The demographics, imaging, pathology and surgical outcome of both groups were compared. Thirty-six of 47 cases from Group A met the inclusion criterion and 36 cases were selected from Group B; 7 of the 36 cases in Group A had unequivocal evidence of residual tumour on the post-operative scan; 5 (14%) of them underwent repeat resection within 6 months post-surgery. In Group B, ioMRI revealed unequivocal evidence of residual tumour in 11 of the 36 cases following initial resection. In 10 of these 11 cases, repeat resections were performed during the same surgical episode and none of these 11 cases required repeat surgery in the following 6 months. Early repeat resection rate was significantly different between both groups (p = 0.003). Following the advent of ioMRI at our institution, the need for repeat resection within 6 months has been prevented in cases where ioMRI revealed unequivocal evidence of residual tumour.
Quantifying recent erosion and sediment delivery using probability sampling: A case study
Jack Lewis
2002-01-01
Abstract - Estimates of erosion and sediment delivery have often relied on measurements from locations that were selected to be representative of particular terrain types. Such judgement samples are likely to overestimate or underestimate the mean of the quantity of interest. Probability sampling can eliminate the bias due to sample selection, and it permits the...
ERIC Educational Resources Information Center
Miller, Matthew W.
2013-01-01
This multiple case study examines the role of the community college president in fundraising as perceived by selected Michigan community college presidents. Over the past few decades, fundraising from private sources has become increasingly important in the fiscal landscape of community colleges. Pfeffer and Salancik's (1978) work in resource…
An Approach for Selecting a Theoretical Framework for the Evaluation of Training Programs
ERIC Educational Resources Information Center
Tasca, Jorge Eduardo; Ensslin, Leonardo; Ensslin, Sandra Rolim; Alves, Maria Bernardete Martins
2010-01-01
Purpose: This research paper proposes a method for selecting references related to a research topic, and seeks to exemplify it for the case of a study evaluating training programs. The method is designed to identify references with high academic relevance in databases accessed via the internet, using a bibliometric analysis to sift the selected…
Blindness and Selective Mutism: One Student's Response to Voice-Output Devices
ERIC Educational Resources Information Center
Holley, Mary; Johnson, Ashli; Herzberg, Tina
2014-01-01
This case study was designed to measure the response of one student with blindness and selective mutism to the intervention of voice-output devices across two years and two different teachers in two instructional settings. Before the introduction of the voice output devices, the student did not choose to communicate using spoken language or…
The Silent Minority: Supporting Students with Selective Mutism Using Systemic Perspectives
ERIC Educational Resources Information Center
Lawrence, Zena
2017-01-01
Selective Mutism (SM) is an under-researched area of child development. While the incidence rate is low, the impact of this difficulty can be pervasive and can present as a significant risk for student mental health and wellbeing. The following article presents a case study focusing on parent-student intervention for a preadolescent male, using an…
Sam A. Flanagan; David Fuller; Leonard Job; Sam Morrison
2012-01-01
Post-treatment erosion was observed for 41 decommissioned road stream crossings in three northern California watersheds. Sites were purposefully selected in order to characterize the nature and range of post-treatment erosional responses. Sites with the highest visible erosion were selected in order to better understand the dominant process and incorporate any...
An 'ecological trap' for yellow warbler nest microhabitat selection
Quresh S. Latif; Sacha K. Heath; John T. Rotenberry
2011-01-01
Contrary to assumptions of habitat selection theory, fi eld studies frequently detect â ecological traps â , where animals prefer habitats conferring lower fi tness than available alternatives. Evidence for traps includes cases where birds prefer breeding habitats associated with relatively high nest predation rates despite the importance of nest survival to avian fi...
ERIC Educational Resources Information Center
Rubin, Rachel B.
2011-01-01
While many selective and moderately selective schools have attempted to increase the numbers of low-income students and students of color in their student body, few have successfully done so. In this qualitative case study, I examine the efforts of an elite, private, liberal arts school, Amherst College, as it increased the socioeconomic diversity…
ERIC Educational Resources Information Center
Frels, Rebecca Karen
2010-01-01
The purpose of this qualitative, collective case study was to explore selected mentors' perceptions and experiences of the dyadic mentoring relationship in SBM. A second purpose was to build on the qualitative body of research (Spencer, 2004, 2007) for understanding roles, purposes, approaches, and experiences of the relationship process with…
The search and selection of assisted living facilities by elders and family.
Castle, Nicholas G; Sonon, Kristen E
2007-08-01
In this study, we examine factors associated with the search, selection, and satisfaction of residents and family members in assisted living. Data were collected from 375 residents of 25 assisted living facilities matched with 375 family members. We conducted face-to-face interviews with the residents to determine: (1) the principal decision maker; (2) the process of searching for a facility; (3) the factors crucial to facility selection; (4) the time frame from the relocation decision to relocation; and (5) satisfaction with selection. Similar questions were asked of family members, using a mail survey. Residents described themselves as extremely influential in 39% of cases when searching for a facility, and in 27% of cases when selecting a facility. Quality, cost, and location were the most influential factors for both residents and family members in selecting a facility. Almost all residents and family would use different search and selection processes if they had to select a facility again, and almost all were dissatisfied with the sources of information available. Consumers and policy makers both favor the use of assisted living settings; but, the information available to choose a setting is far from ideal, and may represent a barrier to both consumer and policy makers' agendas.
Vail, III, William Banning
2000-01-01
Methods of operation of different types of multiple electrode apparatus vertically disposed in a cased well to measure information related to the resistivity of adjacent geological formations from within the cased well are described. The multiple electrode apparatus has a minimum of two spaced apart voltage measurement electrodes that electrically engage a first portion of the interior of the cased well and that provide at least first voltage information. Current control means are used to control the magnitude of any selected current that flows along a second portion of the interior of the casing to be equal to a predetermined selected constant. The first portion of the interior of the cased well is spaced apart from the second portion of the interior of the cased well. The first voltage information and the predetermined selected constant value of any selected current flowing along the casing are used in part to determine a magnitude related to the formation resistivity adjacent to the first portion of the interior of the cased well. Methods and apparatus having a plurality of voltage measurement electrodes are disclosed that provide voltage related information in the presence of constant currents flowing along the casing which is used to provide formation resistivity.
NASA Astrophysics Data System (ADS)
Erkol, Şirag; Yücel, Gönenç
In this study, the problem of seed selection is investigated. This problem is mainly treated as an optimization problem, which is proved to be NP-hard. There are several heuristic approaches in the literature which mostly use algorithmic heuristics. These approaches mainly focus on the trade-off between computational complexity and accuracy. Although the accuracy of algorithmic heuristics are high, they also have high computational complexity. Furthermore, in the literature, it is generally assumed that complete information on the structure and features of a network is available, which is not the case in most of the times. For the study, a simulation model is constructed, which is capable of creating networks, performing seed selection heuristics, and simulating diffusion models. Novel metric-based seed selection heuristics that rely only on partial information are proposed and tested using the simulation model. These heuristics use local information available from nodes in the synthetically created networks. The performances of heuristics are comparatively analyzed on three different network types. The results clearly show that the performance of a heuristic depends on the structure of a network. A heuristic to be used should be selected after investigating the properties of the network at hand. More importantly, the approach of partial information provided promising results. In certain cases, selection heuristics that rely only on partial network information perform very close to similar heuristics that require complete network data.
Validation of Reference Genes in mRNA Expression Analysis Applied to the Study of Asthma.
Segundo-Val, Ignacio San; Sanz-Lozano, Catalina S
2016-01-01
The quantitative Polymerase Chain Reaction is the most used technique for the study of gene expression. To correct putative experimental errors of this technique is necessary normalizing the expression results of the gene of interest with the obtained for reference genes. Here, we describe an example of the process to select reference genes. In this particular case, we select reference genes for expression studies in the peripheral blood mononuclear cells of asthmatic patients.
ERIC Educational Resources Information Center
Caruso, Shirley J.
2016-01-01
This single instrumental qualitative case study explores and thickly describes job performance outcomes based upon the manner in which self-directed learning activities of a purposefully selected sample of 3 construction managers are conducted, mediated by the use of Web 2.0 technology. The data collected revealed that construction managers are…
ERIC Educational Resources Information Center
Epper, Rhonda M., Ed.; Bates, A. W., Ed.
The case studies and analyses in this book address the ways in which higher education institutions are responding to the growing demand for faculty support in the use of technology. Cases were selected from more than 100 institutions that participated in a study by the State Higher Education Executive Officers and the American Productivity &…
ERIC Educational Resources Information Center
Elrod, G. Franklin; Obringer, S. John
Many researchers have attempted to link children's drawings to intelligence. The Goodenough-Harris Draw-a-Man (DAM) and Draw-a-Woman (DAW) test has been accepted as an indicator of intelligence. This study, via examination of specific cases, explored the effect that instruction in drawing cartoons had on the DAM and DAW performance of 16…
ERIC Educational Resources Information Center
Maree, Jacobus G.
2018-01-01
This article reports on the value of career construction counselling (integrating qualitative and quantitative strategies and associated techniques) for a young person. The participant was purposefully selected from a number of people who had sought career counselling in a private practice context. An intrinsic, single-case study design was…
Price, V.; Temples, T.; Hodges, R.; Dai, Z.; Watkins, D.; Imrich, J.
2007-01-01
This document discusses results of applying the Integrated Ground-Water Monitoring Strategy (the Strategy) to actual waste sites using existing field characterization and monitoring data. The Strategy is a systematic approach to dealing with complex sites. Application of such a systematic approach will reduce uncertainty associated with site analysis, and therefore uncertainty associated with management decisions about a site. The Strategy can be used to guide the development of a ground-water monitoring program or to review an existing one. The sites selected for study fall within a wide range of geologic and climatic settings, waste compositions, and site design characteristics and represent realistic cases that might be encountered by the NRC. No one case study illustrates a comprehensive application of the Strategy using all available site data. Rather, within each case study we focus on certain aspects of the Strategy, to illustrate concepts that can be applied generically to all sites. The test sites selected include:Charleston, South Carolina, Naval Weapons Station,Brookhaven National Laboratory on Long Island, New York,The USGS Amargosa Desert Research Site in Nevada,Rocky Flats in Colorado,C-Area at the Savannah River Site in South Carolina, andThe Hanford 300 Area.A Data Analysis section provides examples of detailed data analysis of monitoring data.
Laporte, Silvy; Chapelle, Céline; Caillet, Pascal; Beyens, Marie-Noëlle; Bellet, Florelle; Delavenne, Xavier; Mismetti, Patrick; Bertoletti, Laurent
2017-04-01
Selective serotonin reuptake inhibitors (SSRIs) have been reported to be potentially associated with an increased risk of bleeding. A meta-analysis of observational studies was conducted to quantify this risk. Case-control and cohort studies investigating bleeding risk under SSRI therapy were retrieved by searching the Medline, Pascal, Google Scholar and Scopus databases. Case-control studies were included if they reported bleeding incidents with and without the use of SSRIs and cohort studies were included if they reported the rate of bleeds among SSRI users and non-users. The main outcome was severe bleeding, whatever the site. Only data concerning SSRI belonging to the ATC class N06AB were used. For both case-control and cohort studies, we recorded the adjusted effect estimates and their 95% confidence intervals (CI). Pooled adjusted odds ratio (OR) estimates were computed for case-control and cohort studies using an inverse-variance model. Meta-analysis of the adjusted ORs of 42 observational studies showed a significant association between SSRI use and the risk of bleeding [OR 1.41 (95% CI 1.27-1.57), random effect model, p<0.0001]. The association was found for the 31 case-control studies (1,255,073 patients), with an increased risk of 41% of bleeding [OR 1.41 (95% CI 1.25-1.60)], as well as for the 11 cohort studies including 187,956 patients [OR 1.36 (95% CI 1.12-1.64)]. Subgroup analyses showed that the association remained constant whatever the characteristics of studies. This meta-analysis shows an increased risk of bleeding of at least 36% (from 12% to 64%) based on the high-level of observational studies with SSRIs use. Copyright © 2016 Elsevier Ltd. All rights reserved.
Qiu, Zhengjun; Sun, Jing; Pu, Ying; Jiang, Tao; Cao, Jun; Wu, Weidong
2011-09-01
Transumbilical single incision laparoscopic surgery (SILS) is a new laparoscopic procedure in which only one transumbilical incision is made, demonstrated as a scarless procedure. Here we report a single-center preliminary experience of transumbilical single incision laparoscopic cholecystectomy (SILC) in the treatment of benign gallbladder diseases, defining a single surgeon's learning curve. A total of 80 patients underwent SILC successfully by a single experienced laparoscopic surgeon. The operation was performed following the routine LC procedure. Then the perioperative demographics were recorded and the operative time was used to define the learning curve. The study group included 27 male and 53 female patients with gallstones (56 cases), cholesterol polyps (16 cases), an adenomatous polyp (3 cases), adenomyomatosis (1 case), or complex diseases (4 cases), and all consented to undergo SILC. No patient was converted to normal LC or open surgery. There were no perioperative port-related or surgical complications. The average operative time was 46.9 ± 14.6 min. The average postoperative hospital stay was 1.8 ± 1.3 days. The learning curve of the SILC procedures for this series of selected patients confirmed that SILC is a feasible, safe, and effective approach to the treatment of benign gallbladder diseases. For experienced laparoscopic surgeons, SILC is an easy and safe procedure. Patients benefit from milder pain, a lower incidence of port-related complications, better cosmesis, and fast recovery. The SILC procedure may become another option for the treatment of benign gallbladder diseases for selected patients.
Logistic regression trees for initial selection of interesting loci in case-control studies
Nickolov, Radoslav Z; Milanov, Valentin B
2007-01-01
Modern genetic epidemiology faces the challenge of dealing with hundreds of thousands of genetic markers. The selection of a small initial subset of interesting markers for further investigation can greatly facilitate genetic studies. In this contribution we suggest the use of a logistic regression tree algorithm known as logistic tree with unbiased selection. Using the simulated data provided for Genetic Analysis Workshop 15, we show how this algorithm, with incorporation of multifactor dimensionality reduction method, can reduce an initial large pool of markers to a small set that includes the interesting markers with high probability. PMID:18466557
Jović, Ozren; Smrečki, Neven; Popović, Zora
2016-04-01
A novel quantitative prediction and variable selection method called interval ridge regression (iRR) is studied in this work. The method is performed on six data sets of FTIR, two data sets of UV-vis and one data set of DSC. The obtained results show that models built with ridge regression on optimal variables selected with iRR significantly outperfom models built with ridge regression on all variables in both calibration (6 out of 9 cases) and validation (2 out of 9 cases). In this study, iRR is also compared with interval partial least squares regression (iPLS). iRR outperfomed iPLS in validation (insignificantly in 6 out of 9 cases and significantly in one out of 9 cases for p<0.05). Also, iRR can be a fast alternative to iPLS, especially in case of unknown degree of complexity of analyzed system, i.e. if upper limit of number of latent variables is not easily estimated for iPLS. Adulteration of hempseed (H) oil, a well known health beneficial nutrient, is studied in this work by mixing it with cheap and widely used oils such as soybean (So) oil, rapeseed (R) oil and sunflower (Su) oil. Binary mixture sets of hempseed oil with these three oils (HSo, HR and HSu) and a ternary mixture set of H oil, R oil and Su oil (HRSu) were considered. The obtained accuracy indicates that using iRR on FTIR and UV-vis data, each particular oil can be very successfully quantified (in all 8 cases RMSEP<1.2%). This means that FTIR-ATR coupled with iRR can very rapidly and effectively determine the level of adulteration in the adulterated hempseed oil (R(2)>0.99). Copyright © 2015 Elsevier B.V. All rights reserved.
Computer-aided diagnosis of contrast-enhanced spectral mammography: A feasibility study.
Patel, Bhavika K; Ranjbar, Sara; Wu, Teresa; Pockaj, Barbara A; Li, Jing; Zhang, Nan; Lobbes, Mark; Zhang, Bin; Mitchell, J Ross
2018-01-01
To evaluate whether the use of a computer-aided diagnosis-contrast-enhanced spectral mammography (CAD-CESM) tool can further increase the diagnostic performance of CESM compared with that of experienced radiologists. This IRB-approved retrospective study analyzed 50 lesions described on CESM from August 2014 to December 2015. Histopathologic analyses, used as the criterion standard, revealed 24 benign and 26 malignant lesions. An expert breast radiologist manually outlined lesion boundaries on the different views. A set of morphologic and textural features were then extracted from the low-energy and recombined images. Machine-learning algorithms with feature selection were used along with statistical analysis to reduce, select, and combine features. Selected features were then used to construct a predictive model using a support vector machine (SVM) classification method in a leave-one-out-cross-validation approach. The classification performance was compared against the diagnostic predictions of 2 breast radiologists with access to the same CESM cases. Based on the SVM classification, CAD-CESM correctly identified 45 of 50 lesions in the cohort, resulting in an overall accuracy of 90%. The detection rate for the malignant group was 88% (3 false-negative cases) and 92% for the benign group (2 false-positive cases). Compared with the model, radiologist 1 had an overall accuracy of 78% and a detection rate of 92% (2 false-negative cases) for the malignant group and 62% (10 false-positive cases) for the benign group. Radiologist 2 had an overall accuracy of 86% and a detection rate of 100% for the malignant group and 71% (8 false-positive cases) for the benign group. The results of our feasibility study suggest that a CAD-CESM tool can provide complementary information to radiologists, mainly by reducing the number of false-positive findings. Copyright © 2017 Elsevier B.V. All rights reserved.
2012-01-01
Background Vector control programs, which have focused mainly on the patient house and peridomestic areas around dengue cases, have not produced the expected impact on transmission. This project will evaluate the assumption that the endemic/epidemic transmission of dengue begins around peridomestic vicinities of the primary cases. Its objective is to assess the relationship between symptomatic dengue case exposure and peridomestic infection incidence. Methods/Design A prospective cohort study will be conducted (in Tepalcingo and Axochiapan, in the state of Morelos, Mexico), using the state surveillance system for the detection of incident cases. Paired blood specimens will be collected from both the individuals who live with the incident cases and a sample of subjects residing within a 25-meter radius of such cases (exposed cohort), in order to measure dengue-specific antibodies. Other subjects will be selected from areas which have not presented any incident cases within 200 meters, during the two months preceding the sampling (non-exposed cohort). Symptomatic/asymptomatic incident infection will be considered as the dependent variable, exposure to confirmed dengue cases, as the principal variable, and the socio-demographic, environmental and socio-cultural conditions of the subjects, as additional explanatory variables. Discussion Results indicating a high infection rate among the exposed subjects would justify the application of peridomestic control measures and call for an evaluation of alternate causes for insufficient program impact. On the other hand, a low incidence of peridomestic-infected subjects would support the hypothesis that infection occurs outside the domicile, and would thus explain why the vector control measures applied in the past have exerted such a limited impact on cases incidence rates. The results of the present study may therefore serve to reassess site selection for interventions of this type. PMID:22471857
Selection bias in genetic-epidemiological studies of cleft lip and palate
DOE Office of Scientific and Technical Information (OSTI.GOV)
Christensen, K.; Holm, N.V.; Kock, K.
1992-09-01
The possible impact of selection bias in genetic and epidemiological studies of cleft lip and palate was studied, using three nationwide ascertainment sources and an autopsy study in a 10% sample of the Danish population. A total of 670 cases were identified. Two national record systems, when used together, were found suitable for ascertaining facial cleft in live births. More than 95% ascertainment was obtained by means of surgical files for cleft lip (with or without cleft palate) without associated malformations/syndromes. However, surgical files could be a poor source for studying isolated cleft palate (CP) (only a 60% and biasedmore » ascertainment), and they cannot be used to study the prevalence of associated malformations or syndromes in facial cleft cases. The male:female ratio was 0.88 in surgically treated cases of CP and was 1.5 in nonoperated CP cases, making the overall sex ratio for CP 1.1 (95% confidence limits 0.86-1.4) The sex ratio for CP without associated malformation was 1.1 (95% confidence limits 0.84-1.6). One of the major test criteria in CP multifactorial threshold models (higher CP liability among male CP relatives) must be reconsidered, if other investigations confirm that a CP sex-ratio reversal to male predominance occurs when high ascertainment is achieved. 24 refs., 1 fig., 4 tabs.« less
S&T converging trends in dealing with disaster: A review on AI tools
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hasan, Abu Bakar, E-mail: abakarh@usim.edu.my; Isa, Mohd Hafez Mohd.
Science and Technology (S&T) has been able to help mankind to solve or minimize problems when arise. Different methodologies, techniques and tools were developed or used for specific cases by researchers, engineers, scientists throughout the world, and numerous papers and articles have been written by them. Nine selected cases such as flash flood, earthquakes, workplace accident, fault in aircraft industry, seismic vulnerability, disaster mitigation and management, and early fault detection in nuclear industry have been studied. This paper looked at those cases, and their results showed nearly 60% uses artificial intelligence (AI) as a tool. This paper also did somemore » review that will help young researchers in deciding the types of AI tools to be selected; thus proving the future trends in S&T.« less
S&T converging trends in dealing with disaster: A review on AI tools
NASA Astrophysics Data System (ADS)
Hasan, Abu Bakar; Isa, Mohd. Hafez Mohd.
2016-01-01
Science and Technology (S&T) has been able to help mankind to solve or minimize problems when arise. Different methodologies, techniques and tools were developed or used for specific cases by researchers, engineers, scientists throughout the world, and numerous papers and articles have been written by them. Nine selected cases such as flash flood, earthquakes, workplace accident, fault in aircraft industry, seismic vulnerability, disaster mitigation and management, and early fault detection in nuclear industry have been studied. This paper looked at those cases, and their results showed nearly 60% uses artificial intelligence (AI) as a tool. This paper also did some review that will help young researchers in deciding the types of AI tools to be selected; thus proving the future trends in S&T.
[Costly drugs: analysis and proposals for the Mercosur countries].
Marín, Gustavo H; Polach, María Andrea
2011-08-01
Determine how the Mercosur countries access, regulate, and finance costly drugs and propose joint selection and financing strategies at the subregional level. Qualitative design, using content analyses of primary and secondary sources, document reviews, interviews, focus groups, and case studies. The variables selected included: selection criteria, access, financing, and regulations in the various countries. Costly drugs were divided into those that do not alter the natural course of the disease and those with demonstrated efficacy, using the defined daily dose to compare the costs of classical treatments and those involving costly drugs. The Mercosur countries generally lack formal strategies for dealing with the demand for costly drugs, and governments and insurers wind up financing them by court order. The case studies show that there are costly drugs whose efficacy has not been established but that nonetheless generate demand. The fragmentation of procurement, international commitments with regard to intellectual property, and low negotiating power exponentially increase the price of costly drugs, putting health system finances in jeopardy. Costly drugs must be regulated and rationally selected so that only those that substantively benefit people are accepted. To finance the drugs so selected, common country strategies are needed that include such options as flexible in trade agreements, the creation of national resource funds, or joint procurement by countries to enhance their negotiating power.
Variation in day-case nasal surgery - why cannot we improve our day-case rates?
Hopkins, C; Browne, J; Slack, R; Brown, P
2007-02-01
The NHS plan states that 75% of all elective operations should be performed as day-cases. We set out to evaluate day surgery rates in sinonasal surgery and to identify factors limiting current practice. Prospective multicentre cohort study. 3128 patients undergoing sinonasal surgery during 2000 and 2001. Same day discharge, complication and readmission rates. There is potential selection bias due to the non-random selection of NHS Trusts and patients in this study. However, as results are similar to Hospital Episode Statistics data such bias is probably small. Only 15.5% of all procedures are performed as day surgery. We are achieving day-case rates of 18, 20 and 6% for nasal polypectomy, intranasal antrostomy and extensive FESS respectively, compared with recently published targets of 90%, 80% and 50%. Factors significantly associated with overnight admission were use of packs, extensive surgery, excess post-operative bleeding and high ASA grade. There was considerable unexplained variation in day-case rates and the use of packs between different surgeons. A third of consultants pack all patients post-operatively. More than 51% of consultants admit all patients, while 5% discharge all patients on the day of surgery. There were no excess adverse events or readmissions amongst the day surgery patients. However, only 17% of in-patients would have liked to be discharged on the day of surgery. Both patient and surgeon must overcome resistance to day case surgery before targets can be reached. Strategies for improving day-case rates in sinonasal surgery. All ASA grade 1 and 2 patients could be considered for day-case surgery, but particularly those with less extensive disease on radiography, and those planned to undergo less extensive procedures. Excess peri-operative bleeding was reported in 6% of patients. There must therefore be provision for overnight admission if required. Greater utilisation of day-case units, selective use of packs, and earlier removal may increase the proportion of patients managed as day-cases. There remains considerable variation in practice at both consultant and trust levels. Units should continue to audit their own figures and compare them against national rates in order to reduce nationwide variation in practice.
Piecewise exponential survival times and analysis of case-cohort data.
Li, Yan; Gail, Mitchell H; Preston, Dale L; Graubard, Barry I; Lubin, Jay H
2012-06-15
Case-cohort designs select a random sample of a cohort to be used as control with cases arising from the follow-up of the cohort. Analyses of case-cohort studies with time-varying exposures that use Cox partial likelihood methods can be computer intensive. We propose a piecewise-exponential approach where Poisson regression model parameters are estimated from a pseudolikelihood and the corresponding variances are derived by applying Taylor linearization methods that are used in survey research. The proposed approach is evaluated using Monte Carlo simulations. An illustration is provided using data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of male smokers in Finland, where a case-cohort study of serum glucose level and pancreatic cancer was analyzed. Copyright © 2012 John Wiley & Sons, Ltd.
Protective effect of intradermal BCG against leprosy; a case-control study in central Brazil.
Rodrigues, M L; Silva, S A; Neto, J C; de Andrade, A L; Martelli, C M; Zicker, F
1992-09-01
A case-control study was undertaken to evaluate the protective efficacy of intradermal BCG against leprosy in a high-endemic area of leprosy in central Brazil. Sixty-two cases and 186 controls were included in the study. Cases were all newly diagnosed leprosy patients under 16 years of age attending an outpatient health service, and all of them were schoolchildren. Three controls under 16 years old, frequency matched by sex and age group, were selected from schools geographically located in the area from which the cases came. The presence of BCG was negatively associated with leprosy, indicating a 5.3 risk of leprosy for those nonvaccinated and protective efficacy of 81%. Paucibacillary patients were more likely to have a BCG scar than multibacillary patients.
Women Are Better at Selecting Gifts than Men
Pollmann, Monique M. H.; van Beest, Ilja
2013-01-01
There is a widespread belief that women are better at selecting gifts than men; however, this claim has not been assessed on the basis of objective criteria. The current studies do exactly that and show that women do indeed make better gift selections for others, regardless of the gender of the receiver and the type of relationship between the giver and receiver. We investigate the mediating role of different aspects of interpersonal sensitivity and reveal that differences in interpersonal interest (measured with an autism questionnaire), but not differences in interpersonal reactivity, explain gender differences in gift selection quality. The current studies thus present the first objective evidence for the claim that women are better in selecting gifts for others and also give an indication of why this is the case. PMID:24386082
The ancestral selection graph under strong directional selection.
Pokalyuk, Cornelia; Pfaffelhuber, Peter
2013-08-01
The ancestral selection graph (ASG) was introduced by Neuhauser and Krone (1997) in order to study populations of constant size which evolve under selection. Coalescence events, which occur at rate 1 for every pair of lines, lead to joint ancestry. In addition, splitting events in the ASG at rate α, the scaled selection coefficient, produce possible ancestors, such that the real ancestor depends on the ancestral alleles. Here, we use the ASG in the case without mutation in order to study fixation of a beneficial mutant. Using our main tool, a reversibility property of the ASG, we provide a new proof of the fact that a beneficial allele fixes roughly in time (2logα)/α if α is large. Copyright © 2012 Elsevier Inc. All rights reserved.
The genealogy of samples in models with selection.
Neuhauser, C; Krone, S M
1997-02-01
We introduce the genealogy of a random sample of genes taken from a large haploid population that evolves according to random reproduction with selection and mutation. Without selection, the genealogy is described by Kingman's well-known coalescent process. In the selective case, the genealogy of the sample is embedded in a graph with a coalescing and branching structure. We describe this graph, called the ancestral selection graph, and point out differences and similarities with Kingman's coalescent. We present simulations for a two-allele model with symmetric mutation in which one of the alleles has a selective advantage over the other. We find that when the allele frequencies in the population are already in equilibrium, then the genealogy does not differ much from the neutral case. This is supported by rigorous results. Furthermore, we describe the ancestral selection graph for other selective models with finitely many selection classes, such as the K-allele models, infinitely-many-alleles models. DNA sequence models, and infinitely-many-sites models, and briefly discuss the diploid case.
The Genealogy of Samples in Models with Selection
Neuhauser, C.; Krone, S. M.
1997-01-01
We introduce the genealogy of a random sample of genes taken from a large haploid population that evolves according to random reproduction with selection and mutation. Without selection, the genealogy is described by Kingman's well-known coalescent process. In the selective case, the genealogy of the sample is embedded in a graph with a coalescing and branching structure. We describe this graph, called the ancestral selection graph, and point out differences and similarities with Kingman's coalescent. We present simulations for a two-allele model with symmetric mutation in which one of the alleles has a selective advantage over the other. We find that when the allele frequencies in the population are already in equilibrium, then the genealogy does not differ much from the neutral case. This is supported by rigorous results. Furthermore, we describe the ancestral selection graph for other selective models with finitely many selection classes, such as the K-allele models, infinitely-many-alleles models, DNA sequence models, and infinitely-many-sites models, and briefly discuss the diploid case. PMID:9071604
Predictive validity of the Biomedical Admissions Test: an evaluation and case study.
McManus, I C; Ferguson, Eamonn; Wakeford, Richard; Powis, David; James, David
2011-01-01
There has been an increase in the use of pre-admission selection tests for medicine. Such tests need to show good psychometric properties. Here, we use a paper by Emery and Bell [2009. The predictive validity of the Biomedical Admissions Test for pre-clinical examination performance. Med Educ 43:557-564] as a case study to evaluate and comment on the reporting of psychometric data in the field of medical student selection (and the comments apply to many papers in the field). We highlight pitfalls when reliability data are not presented, how simple zero-order associations can lead to inaccurate conclusions about the predictive validity of a test, and how biases need to be explored and reported. We show with BMAT that it is the knowledge part of the test which does all the predictive work. We show that without evidence of incremental validity it is difficult to assess the value of any selection tests for medicine.
Zhang, Beibei; Zhang, Weiming; Yan, Liang; Wang, Daogang
2017-03-01
The methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism is closely related to the acute lymphoblastic leukaemia (ALL) indicated by many previous epidemiologic studies. However, their conclusions were still conflicting. Our aim is to evaluate their associations using a more comprehensive updated meta-analysis. Electronic searches were conducted to select published studies prior to February, 2016. Totally, 39 case-control studies including 6551 ALL cases and 10,918 controls were selected in current meta-analysis. The association was detected significantly between MTHFR C677T polymorphism and ALL reducing susceptibility. Our results indicate that the MTHFR C677T polymorphism may be a promising ALL biomarker and studies to explore the protein levels of the variants and their functional role are required for the definitive conclusions. Copyright © 2017 Elsevier B.V. All rights reserved.
NASA Technical Reports Server (NTRS)
Lovejoy, Andrew E.; Hilburger, Mark W.; Chunchu, Prasad B.
2010-01-01
A design study was conducted to investigate the effect shell buckling knockdown factor (SBKF), internal pressure and aluminum alloy material selection on the structural weight of stiffened cylindrical shells. Two structural optimization codes were used for the design study to determine the optimum minimum-weight design for a series of design cases, and included an in-house developed genetic algorithm (GA) code and PANDA2. Each design case specified a unique set of geometry, material, knockdown factor combinations and loads. The resulting designs were examined and compared to determine the effects of SBKF, internal pressure and material selection on the acreage design weight and controlling failure mode. This design study shows that use of less conservative SBKF values, including internal pressure, and proper selection of material alloy can result in significant weight savings for stiffened cylinders. In particular, buckling-critical cylinders with integrally machined stiffener construction can benefit from the use of thicker plate material that enables taller stiffeners, even when the stiffness, strength and density properties of these materials appear to be inferior.
Transportation and general aviation in Virginia
NASA Technical Reports Server (NTRS)
1975-01-01
The diversity of Virginia is examined with respect to its transportation facilities and services, the Virginia Air Transportation System Plan, regionalism, and selected case studies of individual facilities.
Selection of Thermal Worst-Case Orbits via Modified Efficient Global Optimization
NASA Technical Reports Server (NTRS)
Moeller, Timothy M.; Wilhite, Alan W.; Liles, Kaitlin A.
2014-01-01
Efficient Global Optimization (EGO) was used to select orbits with worst-case hot and cold thermal environments for the Stratospheric Aerosol and Gas Experiment (SAGE) III. The SAGE III system thermal model changed substantially since the previous selection of worst-case orbits (which did not use the EGO method), so the selections were revised to ensure the worst cases are being captured. The EGO method consists of first conducting an initial set of parametric runs, generated with a space-filling Design of Experiments (DoE) method, then fitting a surrogate model to the data and searching for points of maximum Expected Improvement (EI) to conduct additional runs. The general EGO method was modified by using a multi-start optimizer to identify multiple new test points at each iteration. This modification facilitates parallel computing and decreases the burden of user interaction when the optimizer code is not integrated with the model. Thermal worst-case orbits for SAGE III were successfully identified and shown by direct comparison to be more severe than those identified in the previous selection. The EGO method is a useful tool for this application and can result in computational savings if the initial Design of Experiments (DoE) is selected appropriately.
Integrated assessment in the Mediterranean: the CIRCE case studies
NASA Astrophysics Data System (ADS)
Goodess, C. M.; Agnew, M. D.; Hemming, D.; Giannakopoulos, C.
2012-04-01
The heterogeneous nature of the Mediterranean environment, combined with a wide diversity of economic, social and cultural identities, make this region particularly amenable to integrated research on climate change impacts, vulnerabilities, and adaptive response. Within the framework of the EU FP7 CIRCE project, eleven case-study locations were selected to reflect three generic environments (urban, rural and coastal), to quantify current and future climate change and to assess the potential consequences to human communities and ecosystems at the regional to local scale. The case studies (Athens, Beirut, Alexandria, Tuscany, Apulia, Tel Hadya, Judean Foothills, Gulf of Valencia, Gulf of Oran, Gulf of Gabes, West Nile Delta) were chosen to reflect the east-west and north-south contrasts across the Mediterranean, using common selection criteria. A rigorous common framework, referred to as the CIRCE Case studies Integrating Framework was developed to facilitate a structured and systematic basis for identifying and selecting indicators. Within this framework, climate dynamics is viewed as a key driver of changes in social and biogeophysical systems and is modulated by the inherent dynamics of these systems. The top-down, indicator-based approach was complemented by a bottom-up approach involving local and regional stakeholders. A participatory level of involvement was aimed for, with stakeholder dialogue on an informal basis throughout the project, culminating in a series of more formal regional stakeholder workshops. Identification and construction of physical and socio-economic indicators was the most challenging and time-consuming aspect of the case-study work. A detailed set of selection criteria was defined and the process of reviewing and refining indicators was iterative. Nonetheless, a number of data and methodological challenges were encountered. Despite these issues, indicator linkages diagrams provided a useful preparatory stage for structuring the integrated assessment for each case study. In the first and major assessment stage, impacts and vulnerability due to exposure to hazards associated with current and recent climate variability and change were explored using observed data. This then provided the context for considering future changes. The latter work was based on climate projections derived from the CIRCE global and regional climate model simulations which have the main novel characteristic of incorporating coupling between the Mediterranean Sea and atmosphere. Natural and human systems in all eleven case studies were found to be vulnerable to current climate variability and change as well as to social dynamics or drivers. The climate projections of increases in mean and extreme high temperature and decreases in precipitation are considered to be robust, although there is uncertainty with regards to the magnitude of change. They indicate that all case studies will experience continuing and increasing vulnerability to climate change in the absence of mitigation or adaptation. Projections for other extreme weather events, such as heavy precipitation and flooding, are highly uncertain, but any increase in such events would further increase vulnerability. At the same time, social dynamics and drivers such as population growth (at least in the short term and in the southern Mediterranean) are likely to further increase vulnerability.
Selected Regional Judicial Officer Cases, 2005 - Present
This dataset contains selected cases involving EPA's Regional Judicial Officers (RJOs) from 2005 to present. EPA's Regional Judicial Officers (RJOs) perform adjudicatory functions and act as Agency neutrals in administrative cases. EPA's RJOs are senior attorneys with backgrounds in EPA enforcement, general law, or both.
Intracranial haemorrhage and use of selective serotonin reuptake inhibitors
de Abajo, Francisco J; Jick, Hershel; Derby, Laura; Jick, Susan; Schmitz, Stephen
2000-01-01
Aims In the past few years an increasing number of bleeding disorders have been reported in association with the use of selective serotonin reuptake inhibitors (SSRIs), including serious cases of intracranial haemorrhage, raising concerns about the safety of this class of drugs. The present study was performed to test the hypothesis of an increased risk of intracranial haemorrhage associated with the use of SSRIs. Methods We carried out a case-control study nested in a cohort of antidepressants users with the UK-based General Practice Research Database (GPRD) as the primary source of information. The study cohort encompassed subjects aged between 18 and 79 years who received a first-time prescription for any antidepressant from January, 1990 to October, 1997. Patients with presenting conditions or treatments that could be associated with an increased risk of intracranial haemorrhage were excluded from the cohort. Patients were followed-up until the occurrence of an idiopathic intracranial haemorrhage. Up to four controls per case, matched on age, sex, calendar time and practice were randomly selected from the study cohort. We estimated adjusted odds ratios and 95% confidence intervals of intracranial haemorrhage with current use of SSRIs and other antidepressants as compared with nonuse using conditional logistic regression. Results We identified 65 cases of idiopathic intracranial haemorrhage and 254 matched controls. Current exposure to SSRIs was ascertained in 7 cases (10.8%) and 24 controls (9.7%) resulting in an adjusted OR (95%CI) of 0.8 (0.3,2.3). The estimate for ‘other antidepressants’ was 0.7 (0.3,1.6). The effect measures were not modified by gender or age. No effect related to dose or treatment duration was detected. The risk estimates did not change according to the location of bleeding (intracerebral or subarachnoid). Conclusions Our results are not compatible with a major increased risk of intracranial haemorrhage among users of SSRIs or other antidepressants at large. However, smaller but still relevant increased risks cannot be ruled out. PMID:10886117
An improved wrapper-based feature selection method for machinery fault diagnosis
2017-01-01
A major issue of machinery fault diagnosis using vibration signals is that it is over-reliant on personnel knowledge and experience in interpreting the signal. Thus, machine learning has been adapted for machinery fault diagnosis. The quantity and quality of the input features, however, influence the fault classification performance. Feature selection plays a vital role in selecting the most representative feature subset for the machine learning algorithm. In contrast, the trade-off relationship between capability when selecting the best feature subset and computational effort is inevitable in the wrapper-based feature selection (WFS) method. This paper proposes an improved WFS technique before integration with a support vector machine (SVM) model classifier as a complete fault diagnosis system for a rolling element bearing case study. The bearing vibration dataset made available by the Case Western Reserve University Bearing Data Centre was executed using the proposed WFS and its performance has been analysed and discussed. The results reveal that the proposed WFS secures the best feature subset with a lower computational effort by eliminating the redundancy of re-evaluation. The proposed WFS has therefore been found to be capable and efficient to carry out feature selection tasks. PMID:29261689
A systematic approach to selecting task relevant neurons.
Kahn, Kevin; Saxena, Shreya; Eskandar, Emad; Thakor, Nitish; Schieber, Marc; Gale, John T; Averbeck, Bruno; Eden, Uri; Sarma, Sridevi V
2015-04-30
Since task related neurons cannot be specifically targeted during surgery, a critical decision to make is to select which neurons are task-related when performing data analysis. Including neurons unrelated to the task degrade decoding accuracy and confound neurophysiological results. Traditionally, task-related neurons are selected as those with significant changes in firing rate when a stimulus is applied. However, this assumes that neurons' encoding of stimuli are dominated by their firing rate with little regard to temporal dynamics. This paper proposes a systematic approach for neuron selection, which uses a likelihood ratio test to capture the contribution of stimulus to spiking activity while taking into account task-irrelevant intrinsic dynamics that affect firing rates. This approach is denoted as the model deterioration excluding stimulus (MDES) test. MDES is compared to firing rate selection in four case studies: a simulation, a decoding example, and two neurophysiology examples. The MDES rankings in the simulation match closely with ideal rankings, while firing rate rankings are skewed by task-irrelevant parameters. For decoding, 95% accuracy is achieved using the top 8 MDES-ranked neurons, while the top 12 firing-rate ranked neurons are needed. In the neurophysiological examples, MDES matches published results when firing rates do encode salient stimulus information, and uncovers oscillatory modulations in task-related neurons that are not captured when neurons are selected using firing rates. These case studies illustrate the importance of accounting for intrinsic dynamics when selecting task-related neurons and following the MDES approach accomplishes that. MDES selects neurons that encode task-related information irrespective of these intrinsic dynamics which can bias firing rate based selection. Copyright © 2015 Elsevier B.V. All rights reserved.
Guarín, J F; Ruegg, P L
2016-10-01
The primary objective of this study was to describe and compare anatomical characteristics of teats before and after machine milking adjusted for parity and teat location (front versus rear). The second objective was to determine if selected milking and anatomical characteristics of teats were associated with occurrence of clinical mastitis. To address objective 1, a cross-sectional study was done to describe and compare teat dimensions before and after milking (n=1,751 teats from 445 cows). To fulfill objective 2, a case-control study was performed. Quarters having their first case of clinical mastitis in the current lactation from 2 mo before to 2 mo after the day the teats were measured were selected as cases (n=47), provided no other quarters from that cow were affected by clinical mastitis at that time. Three controls (n=141) were matched with each case; these were selected from quarters that did not experience any case of clinical mastitis during their current lactation. A conditional logistic regression model was used to determine associations between teat dimensions and occurrence of clinical mastitis. Primiparous and multiparous Holstein cows were enrolled in both studies. As compared with premilking dimensions, postmilking teats were longer and narrower at the barrel and the apex. Significant interactions between teat position and parity were identified for premilking teat length and diameter of the teat barrel. Premilking, teats were longer and wider with increasing parity. Front teats were longer and wider than rear teats premilking. Also during premilking, differences between the front and rear teat were less at increasing parity. Teat apex diameter was greater for premilking teats of cows in parity ≥3 and the apexes of front teats were wider than those of rear teats. Teats enrolled in the case-control study had twice as many clinical mastitis cases in front quarters compared with rear quarters. Premilking diameter of the teat apex was positively associated with risk of clinical mastitis (odds ratio=1.20 per 1-mm increase in the diameter of the apex of the teat, 95% confidence interval=1.05-1.37). Milking machine-related changes in teat dimensions had no association with occurrence of clinical mastitis. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Mishra, Ashok; Mishra, Subodh; Lahariya, Chandrakant; Jain, Pankaj; Bhadoriya, Rahul S; Shrivastav, Dhiraj; Marathe, Neera
2009-04-01
Measles is a major cause of childhood morbidity and mortality, accounting for nearly half of the morbidity associated with global vaccine preventable diseases. Regular outbreaks of Measles are reported in India, of which only a few are investigated. This study was conducted in the Shivpuri District of Madhya Pradesh (India) to investigate and asses various epidemiological factors associated with measles outbreak. A cross-sectional study was carried out in 30 randomly selected sub-centers in 8 blocks of the Shivpuri District of Madhya Pradesh, covering 212 villages, selected by cluster sampling. The villages, which had reported measles cases, were extensively investigated by the field teams through extensive house-to-house surveys during 12-19 May 2004. A total of 1204 cases with 14 deaths were reported with an attack rate of 6.2% and a case fatality rate of 1.2%. In this study, 17.7% of the cases reported post-measles complications with diarrhea as the most common post measles complication. The routine measles vaccine and Vitamin A supplementation in the area was also less than 30%. The majority of the cases had occurred in the unvaccinated children and in under 5 year old population. There are repeated outbreaks and a long delay in reporting of the cases. The occurrence of cases, in a reasonable proportion of the vaccinated population, points toward the fact that there is a possibility of a vaccine failure in older children. This study calls for an improved surveillance system, an improvement in the cold chain, and enhancements for measles vaccination if India is to achieve the goal of measles elimination.
Kroeker, Kristine; Widdifield, Jessica; Muthukumarana, Saman; Jiang, Depeng; Lix, Lisa M
2017-01-01
Objective This research proposes a model-based method to facilitate the selection of disease case definitions from validation studies for administrative health data. The method is demonstrated for a rheumatoid arthritis (RA) validation study. Study design and setting Data were from 148 definitions to ascertain cases of RA in hospital, physician and prescription medication administrative data. We considered: (A) separate univariate models for sensitivity and specificity, (B) univariate model for Youden’s summary index and (C) bivariate (ie, joint) mixed-effects model for sensitivity and specificity. Model covariates included the number of diagnoses in physician, hospital and emergency department records, physician diagnosis observation time, duration of time between physician diagnoses and number of RA-related prescription medication records. Results The most common case definition attributes were: 1+ hospital diagnosis (65%), 2+ physician diagnoses (43%), 1+ specialist physician diagnosis (51%) and 2+ years of physician diagnosis observation time (27%). Statistically significant improvements in sensitivity and/or specificity for separate univariate models were associated with (all p values <0.01): 2+ and 3+ physician diagnoses, unlimited physician diagnosis observation time, 1+ specialist physician diagnosis and 1+ RA-related prescription medication records (65+ years only). The bivariate model produced similar results. Youden’s index was associated with these same case definition criteria, except for the length of the physician diagnosis observation time. Conclusion A model-based method provides valuable empirical evidence to aid in selecting a definition(s) for ascertaining diagnosed disease cases from administrative health data. The choice between univariate and bivariate models depends on the goals of the validation study and number of case definitions. PMID:28645978
Valuing the Adult Learner in E-Learning: Part Two--Insights from Four Companies
ERIC Educational Resources Information Center
Waight, Consuelo L.; Stewart, Barbara L.
2005-01-01
Purpose--To investigate how the adult learner is valued in e-learning corporate settings. Design/methodology/approach--Case study methodology was used for this research. Four Fortune 500 companies that had active e-learning initiatives for a minimum of four years were selected. Data for the development of the four cases were collected via…
Developing a Customized Program Assessment Methodology for Assurance of Learning: A Case Study
ERIC Educational Resources Information Center
Baker, Hope; Brawley, Dorothy; Campbell, Jane; Capozzoli, Ernest; Malgeri, Linda; Roberts, Gary
2007-01-01
For most academic institutions, selecting and/or designing a Program Assessment methodology for Assurance of Learning is a challenging task. This paper describes the steps taken to establish goals, values and criteria driving this process for a College of Business. In this case analysis, we document the options we explored in finding the right…
ERIC Educational Resources Information Center
Kalimasi, Perpetua Joseph; Herman, Chaya
2016-01-01
This qualitative case study explores the integration of entrepreneurship education (EE) across the curricula in two public universities in Tanzania. Based on Shapero's model of the entrepreneurial event, the feasibility and desirability of EE in the selected universities are analysed. In-depth interviews and document analysis were used for data…
Examining What We Mean by "Collaboration" in Collaborative Action Research: A Cross-Case Analysis
ERIC Educational Resources Information Center
Bruce, Catherine D.; Flynn, Tara; Stagg-Peterson, Shelley
2011-01-01
The purpose of this paper is to report on the nature of collaboration in a multi-year, large-scale collaborative action research project in which a teachers' federation (in Ontario, Canada), university researchers and teachers partnered to investigate teacher-selected topics for inquiry. Over two years, 14 case studies were generated involving six…
Pfaff, Florian; Müller, Thomas; Freuling, Conrad M; Fehlner-Gardiner, Christine; Nadin-Davis, Susan; Robardet, Emmanuelle; Cliquet, Florence; Vuta, Vlad; Hostnik, Peter; Mettenleiter, Thomas C; Beer, Martin; Höper, Dirk
2018-02-10
Live-attenuated rabies virus strains such as those derived from the field isolate Street Alabama Dufferin (SAD) have been used extensively and very effectively as oral rabies vaccines for the control of fox rabies in both Europe and Canada. Although these vaccines are safe, some cases of vaccine-derived rabies have been detected during rabies surveillance accompanying these campaigns. In recent analysis it was shown that some commercial SAD vaccines consist of diverse viral populations, rather than clonal genotypes. For cases of vaccine-derived rabies, only consensus sequence data have been available to date and information concerning their population diversity was thus lacking. In our study, we used high-throughput sequencing to analyze 11 cases of vaccine-derived rabies, and compared their viral population diversity to the related oral rabies vaccines using pairwise Manhattan distances. This extensive deep sequencing analysis of vaccine-derived rabies cases observed during oral vaccination programs provided deeper insights into the effect of accidental in vivo replication of genetically diverse vaccine strains in the central nervous system of target and non-target species under field conditions. The viral population in vaccine-derived cases appeared to be clonal in contrast to their parental vaccines. The change from a state of high population diversity present in the vaccine batches to a clonal genotype in the affected animal may indicate the presence of a strong bottleneck during infection. In conclusion, it is very likely that these few cases are the consequence of host factors and not the result of the selection of a more virulent genotype. Furthermore, this type of vaccine-derived rabies leads to the selection of clonal genotypes and the selected variants were genetically very similar to potent SAD vaccines that have undergone a history of in vitro selection. Copyright © 2018. Published by Elsevier Ltd.
A probabilistic and multi-objective analysis of lexicase selection and ε-lexicase selection.
Cava, William La; Helmuth, Thomas; Spector, Lee; Moore, Jason H
2018-05-10
Lexicase selection is a parent selection method that considers training cases individually, rather than in aggregate, when performing parent selection. Whereas previous work has demonstrated the ability of lexicase selection to solve difficult problems in program synthesis and symbolic regression, the central goal of this paper is to develop the theoretical underpinnings that explain its performance. To this end, we derive an analytical formula that gives the expected probabilities of selection under lexicase selection, given a population and its behavior. In addition, we expand upon the relation of lexicase selection to many-objective optimization methods to describe the behavior of lexicase selection, which is to select individuals on the boundaries of Pareto fronts in high-dimensional space. We show analytically why lexicase selection performs more poorly for certain sizes of population and training cases, and show why it has been shown to perform more poorly in continuous error spaces. To address this last concern, we propose new variants of ε-lexicase selection, a method that modifies the pass condition in lexicase selection to allow near-elite individuals to pass cases, thereby improving selection performance with continuous errors. We show that ε-lexicase outperforms several diversity-maintenance strategies on a number of real-world and synthetic regression problems.
Rada, E C; Ragazzi, M; Fedrizzi, P
2013-04-01
Municipal solid waste management is a multidisciplinary activity that includes generation, source separation, storage, collection, transfer and transport, processing and recovery, and, last but not least, disposal. The optimization of waste collection, through source separation, is compulsory where a landfill based management must be overcome. In this paper, a few aspects related to the implementation of a Web-GIS based system are analyzed. This approach is critically analyzed referring to the experience of two Italian case studies and two additional extra-European case studies. The first case is one of the best examples of selective collection optimization in Italy. The obtained efficiency is very high: 80% of waste is source separated for recycling purposes. In the second reference case, the local administration is going to be faced with the optimization of waste collection through Web-GIS oriented technologies for the first time. The starting scenario is far from an optimized management of municipal solid waste. The last two case studies concern pilot experiences in China and Malaysia. Each step of the Web-GIS oriented strategy is comparatively discussed referring to typical scenarios of developed and transient economies. The main result is that transient economies are ready to move toward Web oriented tools for MSW management, but this opportunity is not yet well exploited in the sector. Copyright © 2013 Elsevier Ltd. All rights reserved.
Exposure to pistachio pesticides and stillbirth: a case-control study.
Razi, Saeid; Rezaeian, Mohsen; Dehkordi, Fatemeh Ghani; Manshoori, Azita; Goujani, Reza; Vazirinejad, Reza
2016-01-01
Stillbirth is an undesirable outcome of pregnancy. In light of the increasing use of pesticides and growing concerns about the possible health effects of agricultural pesticides, we investigated the effect of exposure to pistachio pesticides on stillbirth in pregnant mothers. This case-control study was conducted in Rafsanjan, Iran from 2011 to 2012. A total of 125 females who had a recent stillbirth were included as the case group, and 250 controls were selected from females who had a recent live birth. For each case, two controls with the nearest propensity score to the case were selected. Data were collected using a protocol developed by the researcher that involved interviewing respondents and reviewing their medical records. Conditional multivariate and univariate logistic regression analysis were performed and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. The ORs of stillbirth in mothers living in pistachio gardens and those who were exposed to sprayed pesticides, in comparison to the controls, were 14.1 (95% CI, 3.3 to 63.4) and 5.0 (95% CI, 1.2 to 28.6), respectively. No significant differences were found in stillbirth rates according to the distance between the mother's residence and a pistachio garden or involvement in agricultural activities. The results of our study showed that exposure to pistachio pesticides during pregnancy may increase the likelihood of stillbirth in mothers.
A robot sets a table: a case for hybrid reasoning with different types of knowledge
NASA Astrophysics Data System (ADS)
Mansouri, Masoumeh; Pecora, Federico
2016-09-01
An important contribution of AI to Robotics is the model-centred approach, whereby competent robot behaviour stems from automated reasoning in models of the world which can be changed to suit different environments, physical capabilities and tasks. However models need to capture diverse (and often application-dependent) aspects of the robot's environment and capabilities. They must also have good computational properties, as robots need to reason while they act in response to perceived context. In this article, we investigate the use of a meta-CSP-based technique to interleave reasoning in diverse knowledge types. We reify the approach through a robotic waiter case study, for which a particular selection of spatial, temporal, resource and action KR formalisms is made. Using this case study, we discuss general principles pertaining to the selection of appropriate KR formalisms and jointly reasoning about them. The resulting integration is evaluated both formally and experimentally on real and simulated robotic platforms.
ERIC Educational Resources Information Center
Chambers, Jack A., Ed.
This collection contains the 20 best papers from a conference at which nearly 300 faculty members presented papers. Those that were selected by juried review include: (1) "Where Have You Been? A Case Study of Successful Implementation of Undergraduate Online Learning Communities" (John Barnett); (2) "A Strange Sense of Disquietude: Understanding…
The Importance of a Team Approach in Working Effectively with Selective Mutism: A Case Study
ERIC Educational Resources Information Center
Borger, Gary W.; Bartley, Dana L.; Armstrong, Norma; Kaatz, Debra; Benson, Dave
2007-01-01
Selective Mutism (SM) in children and adolescents is characterized by a persistent failure to speak in certain social situations including at school or with friends despite the ability to speak and comprehend language. Not due to a specific communication disorder, SM is actually a pervasive psychological problem that lies along the continuum of…
Kweldam, Charlotte F; Nieboer, Daan; Algaba, Ferran; Amin, Mahul B; Berney, Dan M; Billis, Athanase; Bostwick, David G; Bubendorf, Lukas; Cheng, Liang; Compérat, Eva; Delahunt, Brett; Egevad, Lars; Evans, Andrew J; Hansel, Donna E; Humphrey, Peter A; Kristiansen, Glen; van der Kwast, Theodorus H; Magi-Galluzzi, Cristina; Montironi, Rodolfo; Netto, George J; Samaratunga, Hemamali; Srigley, John R; Tan, Puay H; Varma, Murali; Zhou, Ming; van Leenders, Geert J L H
2016-09-01
To assess the interobserver reproducibility of individual Gleason grade 4 growth patterns. Twenty-three genitourinary pathologists participated in the evaluation of 60 selected high-magnification photographs. The selection included 10 cases of Gleason grade 3, 40 of Gleason grade 4 (10 per growth pattern), and 10 of Gleason grade 5. Participants were asked to select a single predominant Gleason grade per case (3, 4, or 5), and to indicate the predominant Gleason grade 4 growth pattern, if present. 'Consensus' was defined as at least 80% agreement, and 'favoured' as 60-80% agreement. Consensus on Gleason grading was reached in 47 of 60 (78%) cases, 35 of which were assigned to grade 4. In the 13 non-consensus cases, ill-formed (6/13, 46%) and fused (7/13, 54%) patterns were involved in the disagreement. Among the 20 cases where at least one pathologist assigned the ill-formed growth pattern, none (0%, 0/20) reached consensus. Consensus for fused, cribriform and glomeruloid glands was reached in 2%, 23% and 38% of cases, respectively. In nine of 35 (26%) consensus Gleason grade 4 cases, participants disagreed on the growth pattern. Six of these were characterized by large epithelial proliferations with delicate intervening fibrovascular cores, which were alternatively given the designation fused or cribriform growth pattern ('complex fused'). Consensus on Gleason grade 4 growth pattern was predominantly reached on cribriform and glomeruloid patterns, but rarely on ill-formed and fused glands. The complex fused glands seem to constitute a borderline pattern of unknown prognostic significance on which a consensus could not be reached. © 2016 John Wiley & Sons Ltd.
Fixation probability in a two-locus intersexual selection model.
Durand, Guillermo; Lessard, Sabin
2016-06-01
We study a two-locus model of intersexual selection in a finite haploid population reproducing according to a discrete-time Moran model with a trait locus expressed in males and a preference locus expressed in females. We show that the probability of ultimate fixation of a single mutant allele for a male ornament introduced at random at the trait locus given any initial frequency state at the preference locus is increased by weak intersexual selection and recombination, weak or strong. Moreover, this probability exceeds the initial frequency of the mutant allele even in the case of a costly male ornament if intersexual selection is not too weak. On the other hand, the probability of ultimate fixation of a single mutant allele for a female preference towards a male ornament introduced at random at the preference locus is increased by weak intersexual selection and weak recombination if the female preference is not costly, and is strong enough in the case of a costly male ornament. The analysis relies on an extension of the ancestral recombination-selection graph for samples of haplotypes to take into account events of intersexual selection, while the symbolic calculation of the fixation probabilities is made possible in a reasonable time by an optimizing algorithm. Copyright © 2016 Elsevier Inc. All rights reserved.
Warpage optimization on a mobile phone case using response surface methodology (RSM)
NASA Astrophysics Data System (ADS)
Lee, X. N.; Fathullah, M.; Shayfull, Z.; Nasir, S. M.; Hazwan, M. H. M.; Shazzuan, S.
2017-09-01
Plastic injection moulding is a popular manufacturing method not only it is reliable, but also efficient and cost saving. It able to produce plastic part with detailed features and complex geometry. However, defects in injection moulding process degrades the quality and aesthetic of the injection moulded product. The most common defect occur in the process is warpage. Inappropriate process parameter setting of injection moulding machine is one of the reason that leads to the occurrence of warpage. The aims of this study were to improve the quality of injection moulded part by investigating the optimal parameters in minimizing warpage using Response Surface Methodology (RSM). Subsequent to this, the most significant parameter was identified and recommended parameters setting was compared with the optimized parameter setting using RSM. In this research, the mobile phone case was selected as case study. The mould temperature, melt temperature, packing pressure, packing time and cooling time were selected as variables whereas warpage in y-direction was selected as responses in this research. The simulation was carried out by using Autodesk Moldflow Insight 2012. In addition, the RSM was performed by using Design Expert 7.0. The warpage in y direction recommended by RSM were reduced by 70 %. RSM performed well in solving warpage issue.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Johnson, J.A.
This study was designed to investigate potential adverse reproductive outcome in veterinary personnel who are exposed to waste anesthetic gas and vapor at levels near the NIOSH recommended standards. Subjects for this case-control study of births with congenital abnormalities and spontaneous abortion, selected from the American Veterinary Medical Association roster, were contacted by mail and asked to complete a screening questionnaire regarding reproductive history. Crude prevalence rates for spontaneous abortion, births with congenital abnormalities and stillbirths, determined on the basis of the responses to the screening questionnaire, showed no excess rates when compared with national statistics. All pregnancies resulting inmore » spontaneous abortion, stillbirth, or birth with congenital abnormality were selected as cases. Controls were selected from the reported normal births on a stratified random basis to match maternal age and pregnancy number for cases. Occupational exposure to waste anesthetic gas and vapor in general was not found to be significantly associated with adverse reproductive outcome when adjustment was made for radiation exposure. For nitrous oxide exposure, however, an odds ratio significantly greater than one was found for spontaneous abortion among female veterinary assistants and wives of exposed male veterinarians. Use of diagnostic x-rays in veterinary practice was associated with spontaneous abortion in exposed females with a statistically significant dose response effect observed in female veterinarians.« less
NASA Astrophysics Data System (ADS)
Rivière, Emmanuel; Marécal, Virginie; Khaykin, Sergey; Amarouche, Nadir; Ghysels, Mélanie; Mappe-Fogaing, Irène; Behera, Abhinna; Held, Gerhard; França, Hermes
2016-04-01
One of the main aims of the TRO-pico project (2010-2015) was to study the variability of overshooting convection at the local scale to try to deduce a typical impact on the TTL water at the global scale. In this study, we've identified local maximum in the water vapour profiles gathered by the balloon-borne hygrometers Pico-SDLA and Flash above Bauru, Brazil (22.3 S) during the TRO-pico campaign. We tried to link them to overshooting cells in the surrounding of Bauru with a trajectory analysis. In this study we select a couple of cases of overshooting convection both sampled by the Bauru S-Band radar and by one of the balloon-borne instruments of the TRO-pico campaign in 2012 and 2013. The selected cases are the case of March 13, 2012 (hereafter M12), sounded by both hygrometers Pico-SDLA and FLASH, and the case of January 26, 2013 (hereafter J13), sounded by Pico-SDLA. For the M12 case, local water vapour enhancements at two different altitudes due to two different cells were reported, with local enhancement of about 0.65 ppmv. For the J26 case, the water enhancement was about 1 ppmv. The corresponding mesoscale simulations with the Brazilian Regional Atmospheric Modelling System (BRAMS) using 3 nested grids with horizontal resolution down to 800 m were carried out. Simulation results are compared to Bauru's radar echo tops and and water vapour in situ measurements. As for the M12 simulation, the model is doing a rather good job in reproducing several overshooting cells, both in severity and timing. Associated stratospheric water budget are computed for each cases.
Nested case-control studies: should one break the matching?
Borgan, Ørnulf; Keogh, Ruth
2015-10-01
In a nested case-control study, controls are selected for each case from the individuals who are at risk at the time at which the case occurs. We say that the controls are matched on study time. To adjust for possible confounding, it is common to match on other variables as well. The standard analysis of nested case-control data is based on a partial likelihood which compares the covariates of each case to those of its matched controls. It has been suggested that one may break the matching of nested case-control data and analyse them as case-cohort data using an inverse probability weighted (IPW) pseudo likelihood. Further, when some covariates are available for all individuals in the cohort, multiple imputation (MI) makes it possible to use all available data in the cohort. In the paper we review the standard method and the IPW and MI approaches, and compare their performance using simulations that cover a range of scenarios, including one and two endpoints.
Computer-aided detection of bladder mass within non-contrast-enhanced region of CT Urography (CTU)
NASA Astrophysics Data System (ADS)
Cha, Kenny H.; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Caoili, Elaine M.; Cohan, Richard H.; Weizer, Alon; Zhou, Chuan
2016-03-01
We are developing a computer-aided detection system for bladder cancer in CT urography (CTU). We have previously developed methods for detection of bladder masses within the contrast-enhanced region of the bladder. In this study, we investigated methods for detection of bladder masses within the non-contrast enhanced region. The bladder was first segmented using a newly developed deep-learning convolutional neural network in combination with level sets. The non-contrast-enhanced region was separated from the contrast-enhanced region with a maximum-intensityprojection- based method. The non-contrast region was smoothed and a gray level threshold was employed to segment the bladder wall and potential masses. The bladder wall was transformed into a straightened thickness profile, which was analyzed to identify lesion candidates as a prescreening step. The lesion candidates were segmented using our autoinitialized cascaded level set (AI-CALS) segmentation method, and 27 morphological features were extracted for each candidate. Stepwise feature selection with simplex optimization and leave-one-case-out resampling were used for training and validation of a false positive (FP) classifier. In each leave-one-case-out cycle, features were selected from the training cases and a linear discriminant analysis (LDA) classifier was designed to merge the selected features into a single score for classification of the left-out test case. A data set of 33 cases with 42 biopsy-proven lesions in the noncontrast enhanced region was collected. During prescreening, the system obtained 83.3% sensitivity at an average of 2.4 FPs/case. After feature extraction and FP reduction by LDA, the system achieved 81.0% sensitivity at 2.0 FPs/case, and 73.8% sensitivity at 1.5 FPs/case.
Gómez-Gómez, Alejandro; Magaña-Aquino, Martin; López-Meza, Salvador; Aranda-Álvarez, Marcelo; Díaz-Ornelas, Dora E; Hernández-Segura, María Guadalupe; Salazar-Lezama, Miguel Ángel; Castellanos-Joya, Martín; Noyola, Daniel E
2015-02-01
Multidrug resistant tuberculosis (MDR-TB) poses problems in treatment, costs and treatment outcomes. It is not known if classically described risk factors for MDR-TB in other countries are the same in Mexico and the frequency of the association between diabetes mellitus (DM) and MDR-TB in our country is not clear. We undertook this study to analyze risk factors associated with the development of MDR-TB, with emphasis on DM. A case-control study in the state of San Luis Potosi (SLP), Mexico was carried out. All pulmonary MDR-TB patients diagnosed in the state of SLP between 1998 and 2013 (36 cases) evaluated at a state pharmacoresistant tuberculosis (TB) clinic and committee; 139 controls were randomly selected from all pulmonary non-multidrug-resistant tuberculosis (non-MDR-TB) cases identified between 2003 and 2008. Cases and controls were diagnosed and treated under programmatic conditions. Age, gender, malnutrition, being a health-care worker, HIV/AIDS status, and drug abuse were not significantly different between MDR-TB and non-MDR-TB patients. Significant differences between MDR-TB and non-MDR-TB patients were DM (47.2 vs. 28.1%; p = 0.028); previous anti-TB treatments (3 vs. 0, respectively; p <0.001), and duration of first anti-TB treatment (8 vs. 6 months, respectively; p <0.001). MDR-TB and DM are associated in 47.2% of MDR TB cases (17/36) in this study. Other recognized factors were not found to be significantly different in MDR-TB compared to non-MDR-TB in this study. Cost-feasible strategies must be implemented in the treatment of DM-TB in order to prevent the selection of MDR-TB. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.
42 CFR 431.980 - Eligibility review procedures.
Code of Federal Regulations, 2011 CFR
2011-10-01
... Estimating Improper Payments in Medicaid and CHIP § 431.980 Eligibility review procedures. (a) Active case reviews. The agency must verify eligibility for all selected active cases for Medicaid and CHIP for the... must review all selected negative cases for Medicaid and CHIP for the review month to determine whether...
42 CFR 431.980 - Eligibility review procedures.
Code of Federal Regulations, 2012 CFR
2012-10-01
... Estimating Improper Payments in Medicaid and CHIP § 431.980 Eligibility review procedures. (a) Active case reviews. The agency must verify eligibility for all selected active cases for Medicaid and CHIP for the... must review all selected negative cases for Medicaid and CHIP for the review month to determine whether...
42 CFR 431.980 - Eligibility review procedures.
Code of Federal Regulations, 2013 CFR
2013-10-01
... Estimating Improper Payments in Medicaid and CHIP § 431.980 Eligibility review procedures. (a) Active case reviews. The agency must verify eligibility for all selected active cases for Medicaid and CHIP for the... must review all selected negative cases for Medicaid and CHIP for the review month to determine whether...
42 CFR 431.980 - Eligibility review procedures.
Code of Federal Regulations, 2014 CFR
2014-10-01
... Estimating Improper Payments in Medicaid and CHIP § 431.980 Eligibility review procedures. (a) Active case reviews. The agency must verify eligibility for all selected active cases for Medicaid and CHIP for the... must review all selected negative cases for Medicaid and CHIP for the review month to determine whether...
Park, Hye Yin; Bae, Sanghyuk; Hong, Yun-Chul
2013-01-01
We investigated the association between particulate matter less than 10 µm in aerodynamic diameter (PM₁₀) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. Among the 819 published studies searched from PubMed and EMBASE using key words related to PM₁₀ exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per 10 µg/m³ increase of daily PM₁₀ from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per 10 µg/m³ increase of daily PM₁₀ for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. We found a significant positive association between PM₁₀ exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.
Müller-Staub, Maria; Stuker-Studer, Ursula
2006-10-01
Case studies, based on actual patients' situations, provide a method of clinical decision making to foster critical thinking in nurses. This paper describes the method and process of group case studies applied in continuous education settings. This method bases on Balints' case supervision and was further developed and combined with the nursing diagnostic process. A case study contains different phases: Pre-phase, selection phase, case delineation and case work. The case provider narratively tells the situation of a patient. This allows the group to analyze and cluster signs and symptoms, to state nursing diagnoses and to derive nursing interventions. Results of the case study are validated by applying the theoretical background and critical appraisal of the case provider. Learning effects of the case studies were evaluated by means of qualitative questionnaires and analyzed according to Mayring. Findings revealed the following categories: a) Patients' problems are perceived in a patient centred way, accurate nursing diagnoses are stated and effective nursing interventions implemented. b) Professional nursing tasks are more purposefully perceived and named more precise. c) Professional nursing relationship, communication and respectful behaviour with patients were perceived in differentiated ways. The theoretical framework is described in the paper "Clinical decision making and critical thinking in the nursing diagnostic process". (Müller-Staub, 2006).
Landfill site selection using combination of GIS and fuzzy AHP, a case study: Iranshahr, Iran.
Torabi-Kaveh, M; Babazadeh, R; Mohammadi, S D; Zaresefat, M
2016-03-09
One of the most important recent challenges in solid waste management throughout the world is site selection of sanitary landfill. Commonly, because of simultaneous effects of social, environmental, and technical parameters on suitability of a landfill site, landfill site selection is a complex process and depends on several criteria and regulations. This study develops a multi-criteria decision analysis (MCDA) process, which combines geographic information system (GIS) analysis with a fuzzy analytical hierarchy process (FAHP), to determine suitable sites for landfill construction in Iranshahr County, Iran. The GIS was used to calculate and classify selected criteria and FAHP was used to assess the criteria weights based on their effectiveness on selection of potential landfill sites. Finally, a suitability map was prepared by overlay analyses and suitable areas were identified. Four suitability classes within the study area were separated, including high, medium, low, and very low suitability areas, which represented 18%, 15%, 55%, and 12% of the study area, respectively. © The Author(s) 2016.
[A case with apraxia of tool use: selective inability to form a hand posture for a tool].
Hayakawa, Yuko; Fujii, Toshikatsu; Yamadori, Atsushi; Meguro, Kenichi; Suzuki, Kyoko
2015-03-01
Impaired tool use is recognized as a symptom of ideational apraxia. While many studies have focused on difficulties in producing gestures as a whole, using tools involves several steps; these include forming hand postures appropriate for the use of certain tool, selecting objects or body parts to act on, and producing gestures. In previously reported cases, both producing and recognizing hand postures were impaired. Here we report the first case showing a selective impairment of forming hand postures appropriate for tools with preserved recognition of the required hand postures. A 24-year-old, right-handed man was admitted to hospital because of sensory impairment of the right side of the body, mild aphasia, and impaired tool use due to left parietal subcortical hemorrhage. His ability to make symbolic gestures, copy finger postures, and orient his hand to pass a slit was well preserved. Semantic knowledge for tools and hand postures was also intact. He could flawlessly select the correct hand postures in recognition tasks. He only demonstrated difficulties in forming a hand posture appropriate for a tool. Once he properly grasped a tool by trial and error, he could use it without hesitation. These observations suggest that each step of tool use should be thoroughly examined in patients with ideational apraxia.
Mobile phone use and risk of tumors: a meta-analysis.
Myung, Seung-Kwon; Ju, Woong; McDonnell, Diana D; Lee, Yeon Ji; Kazinets, Gene; Cheng, Chih-Tao; Moskowitz, Joel M
2009-11-20
Case-control studies have reported inconsistent findings regarding the association between mobile phone use and tumor risk. We investigated these associations using a meta-analysis. We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in August 2008. Two evaluators independently reviewed and selected articles based on predetermined selection criteria. Of 465 articles meeting our initial criteria, 23 case-control studies, which involved 37,916 participants (12,344 patient cases and 25,572 controls), were included in the final analyses. Compared with never or rarely having used a mobile phone, the odds ratio for overall use was 0.98 for malignant and benign tumors (95% CI, 0.89 to 1.07) in a random-effects meta-analysis of all 23 studies. However, a significant positive association (harmful effect) was observed in a random-effects meta-analysis of eight studies using blinding, whereas a significant negative association (protective effect) was observed in a fixed-effects meta-analysis of 15 studies not using blinding. Mobile phone use of 10 years or longer was associated with a risk of tumors in 13 studies reporting this association (odds ratio = 1.18; 95% CI, 1.04 to 1.34). Further, these findings were also observed in the subgroup analyses by methodologic quality of study. Blinding and methodologic quality of study were strongly associated with the research group. The current study found that there is possible evidence linking mobile phone use to an increased risk of tumors from a meta-analysis of low-biased case-control studies. Prospective cohort studies providing a higher level of evidence are needed.
King, D N
1987-01-01
Hospital health sciences libraries represent, for the vast majority of health professionals, the most accessible source for library information and services. Most health professionals do not have available the specialized services of a clinical medical librarian, and rely instead upon general information services for their case-related information needs. The ability of the hospital library to meet these needs and the impact of the information on quality patient care have not been previously examined. A study was conducted in eight hospitals in the Chicago area as a quality assurance project. A total of 176 physicians, nurses, and other health professionals requested information from their hospital libraries related to a current case or clinical situation. They then assessed the quality of information received, its cognitive value, its contribution to patient care, and its impact on case management. Nearly two-thirds of the respondents asserted that they would definitely or probably handle their cases differently as a result of the information provided by the library. Almost all rated the libraries' performance and response highly. An overview of the context and purpose of the study, its methods, selected results, limitations, and conclusions are presented here, as is a review of selected earlier research. PMID:3450340
2013-01-01
Background The aim was to investigate possible associations between glioma (an aggressive type of brain cancer) and occupational exposure to selected agents: combustion products (diesel and gasoline exhaust emissions, benzo(a)pyrene), dusts (animal dust, asbestos, crystalline silica, wood dust) and some other chemical agents (formaldehyde, oil mist, sulphur dioxide). Methods The INTEROCC study included cases diagnosed with glioma during 2000–2004 in sub-regions of seven countries. Population controls, selected from various sampling frames in different centers, were frequency or individually matched to cases by sex, age and center. Face-to-face interviews with the subject or a proxy respondent were conducted by trained interviewers. Detailed information was collected on socio-economic and lifestyle characteristics, medical history and work history. Occupational exposure to the 10 selected agents was assessed by a job exposure matrix (JEM) which provides estimates of the probability and level of exposure for different occupations. Using a 25% probability of exposure in a given occupation in the JEM as the threshold for considering a worker exposed, the lifetime prevalence of exposure varied from about 1% to about 15% for the different agents. Associations between glioma and each of the 10 agents were estimated by conditional logistic regression, and using three separate exposure indices: i) ever vs. never; ii) lifetime cumulative exposure; iii) total duration of exposure. Results The study sample consisted of 1,800 glioma cases and 5,160 controls. Most odds ratio estimates were close to the null value. None of the ten agents displayed a significantly increased odds ratio nor any indication of dose–response relationships with cumulative exposure or with duration of exposure. Conclusion Thus, there was no evidence that these exposures influence risk of glioma. PMID:23587105
NASA Astrophysics Data System (ADS)
Adelina, W.; Kusumastuti, R. D.
2017-01-01
This study is about business strategy selection for green supply chain management (GSCM) for PT XYZ by using Analytic Network Process (ANP). GSCM is initiated as a response to reduce environmental impacts from industrial activities. The purposes of this study are identifying criteria and sub criteria in selecting GSCM Strategy, and analysing a suitable GSCM strategy for PT XYZ. This study proposes ANP network with 6 criteria and 29 sub criteria, which are obtained from the literature and experts’ judgements. One of the six criteria contains GSCM strategy options, namely risk-based strategy, efficiency-based strategy, innovation-based strategy, and closed loop strategy. ANP solves complex GSCM strategy-selection by using a more structured process and considering green perspectives from experts. The result indicates that innovation-based strategy is the most suitable green supply chain management strategy for PT XYZ.
Conceptualizing Agency: Preservice Social Studies Teachers' Thinking about Professional Decisions
ERIC Educational Resources Information Center
Clark, J. Spencer
2011-01-01
This qualitative study investigated preservice social studies teachers' thinking about personal agency. This study used a case study design and was conducted in a semester long undergraduate social studies methods course. The findings drew upon data from eight participants. The participants were selected based on their stated purpose for teaching…
Genome research elucidating environmental adaptation: Dark-fly project as a case study.
Fuse, Naoyuki
2017-08-01
Organisms have the capacity to adapt to diverse environments, and environmental adaptation is a substantial driving force of evolution. Recent progress of genome science has addressed the genetic mechanisms underlying environmental adaptation. Whole genome sequencing has identified adaptive genes selected under particular environments. Genome editing technology enables us to directly test the role(s) of a gene in environmental adaptation. Genome science has also shed light on a unique organism, Dark-fly, which has been reared long-term in the dark. We determined the whole genome sequence of Dark-fly and reenacted environmental selections of the Dark-fly genome to identify the genes related to dark-adaptation. Here I will give an overview of current progress in genome science and summarize our study using Dark-fly, as a case study for environmental adaptation. Copyright © 2017 Elsevier Ltd. All rights reserved.
Single visit nonsurgical endodontic therapy for periapical cysts: A clinical study
Maity, Ipsita; Meena, N.; Kumari, R. Anitha
2014-01-01
Aims: The aim of this study was to assess the outcome of single sitting root canal treatment (RCT) of asymptomatic teeth with periapical cysts. Materials and Methods: Ten maxillary anterior teeth showing periapical lesion on the radiograph was further screened by ultrasound with color power Doppler (CPD) for confirmation of a cyst. The average dimension of the lesions ranged from 1.3 to 1.9 cm. Single sitting RCT was performed on all the selected teeth. Postoperative healing was monitored at regular interval of 3 months, 6 months, and 1 year by using subjective feedback, radiograph, and ultrasound with CPD study. Results: Eight among the ten cases showed either signs of complete healing or healing in progress by the end of 6-12 months. Conclusions: It was observed that single sitting nonsurgical endodontic management of asymptomatic teeth with periapical cyst confirmed by ultrasound was successful in selected cases. PMID:24963246
Single visit nonsurgical endodontic therapy for periapical cysts: A clinical study.
Maity, Ipsita; Meena, N; Kumari, R Anitha
2014-04-01
The aim of this study was to assess the outcome of single sitting root canal treatment (RCT) of asymptomatic teeth with periapical cysts. Ten maxillary anterior teeth showing periapical lesion on the radiograph was further screened by ultrasound with color power Doppler (CPD) for confirmation of a cyst. The average dimension of the lesions ranged from 1.3 to 1.9 cm. Single sitting RCT was performed on all the selected teeth. Postoperative healing was monitored at regular interval of 3 months, 6 months, and 1 year by using subjective feedback, radiograph, and ultrasound with CPD study. Eight among the ten cases showed either signs of complete healing or healing in progress by the end of 6-12 months. It was observed that single sitting nonsurgical endodontic management of asymptomatic teeth with periapical cyst confirmed by ultrasound was successful in selected cases.