Journal articles on the topic 'Confounded design'
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Ghosh, D. K., and S. C. Bagui. "Identification of confounded design and its interactions." Journal of Applied Statistics 25, no. 3 (June 1998): 349–56. http://dx.doi.org/10.1080/02664769823089.
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Weimer, Jon. "Confounded Experimental Designs and Human Factors Research." Proceedings of the Human Factors Society Annual Meeting 31, no. 2 (September 1987): 222–23. http://dx.doi.org/10.1177/154193128703100219.
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The use of confounded factorial designs has been seriously neglected in the human factors literature. A confounded factorial is constructed by systematically confounding blocking variables with one or more interactions which are believed to be statistically insignificant or inconsequential to the researcher. These designs offer the advantages of increased economy and power. These designs are especially useful when research is being conducted on military personnel and subjects must be selected from different military facilities, which may result in heterogeneous subject populations. A concrete example illustrates how confounding of this type can be used to the researcher's advantage through the tailored construction of a confounded design.
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Dülmer, Hermann. "The Factorial Survey." Sociological Methods & Research 45, no. 2 (April 27, 2015): 304–47. http://dx.doi.org/10.1177/0049124115582269.
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The factorial survey is an experimental design consisting of varying situations (vignettes) that have to be judged by respondents. For more complex research questions, it quickly becomes impossible for an individual respondent to judge all vignettes. To overcome this problem, random designs are recommended most of the time, whereas quota designs are not discussed at all. First comparisons of random designs with fractional factorial and D-efficient designs are based on fictitious data, first comparisons with fractional factorial and confounded factorial designs are restricted to theoretical considerations. The aim of this contribution is to compare different designs regarding their reliability and their internal validity. The benchmark for the empirical comparison is established by the estimators from a parsimonious full factorial design, each answered by a sample of 132 students (real instead of fictitious data). Multilevel analyses confirm that, if they exist, balanced confounded factorial designs are ideal. A confounded D-efficient design, as proposed for the first time in this article, is also superior to simple random designs.
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Moradian, Hanieh, Manfred Gossen, and Andreas Lendlein. "Co-delivery of genes can be confounded by bicistronic vector design." MRS Communications 12, no. 2 (February 18, 2022): 145–53. http://dx.doi.org/10.1557/s43579-021-00128-7.
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AbstractMaximizing the efficiency of nanocarrier-mediated co-delivery of genes for co-expression in the same cell is critical for many applications. Strategies to maximize co-delivery of nucleic acids (NA) focused largely on carrier systems, with little attention towards payload composition itself. Here, we investigated the effects of different payload designs: co-delivery of two individual “monocistronic” NAs versus a single bicistronic NA comprising two genes separated by a 2A self-cleavage site. Unexpectedly, co-delivery via the monocistronic design resulted in a higher percentage of co-expressing cells, while predictive co-expression via the bicistronic design remained elusive. Our results will aid the application-dependent selection of the optimal methodology for co-delivery of genes. Graphical abstract
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Kjeldsen, Sverre E., Alexandre Persu, and Michel Azizi. "Design of renal denervation studies not confounded by antihypertensive drugs." Journal of the American Society of Hypertension 9, no. 5 (May 2015): 337–40. http://dx.doi.org/10.1016/j.jash.2015.02.015.
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Green, David W., and David E. Over. "Valuing Intervention and Observation." Quarterly Journal of Experimental Psychology 62, no. 5 (May 2009): 1010–22. http://dx.doi.org/10.1080/17470210802305482.
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Understanding causal relations is fundamental to effective action but causal data can be confounded. We examined the value that participants placed on data derived from a hypothetical intervention or observation. Our materials involved a possible cause (“bottled water”), a possible confound (“food”), and a context (“a restaurant”). We supposed that participants seek to draw as specific a causal inference as possible from presented data and value information sources more highly that allow them to do so. On this basis, we predicted that in circumstances where an intervention removed the confounding causal factor but observation did not, participants would prefer data derived from an intervention when the possible cause was present (the bottled water was drunk) but show the reverse preference when the possible cause was absent (the bottled water was not drunk). Experiment 1 confirmed this prediction. Using a between-subjects design, Experiment 2 tested for a difference in confidence in causal judgements given identical data, including data on the confound, as a function of method of data collection (intervention or observation). There was no significant difference in confidence ratings between the two methods but confidence ratings were sensitive to the probability of an effect (illness) given the cause. Using a within-subjects design, Experiment 3 revealed systematic individual differences in preference for the two methods. Participants were divided between those who considered intervention more confounded and those who considered observation more confounded. Our experiments point to the subtleties of participants’ evaluation of data from studies of human beings.
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McCarty, Lynn S., and Christopher J. Borgert. "Are all current ecotoxicity test results confounded by design and implementation issues?" Integrated Environmental Assessment and Management 12, no. 2 (March 27, 2016): 397–98. http://dx.doi.org/10.1002/ieam.1749.
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KUMAR, PRAKASH, KRISHAN LAL, ANIRBAN MUKHERJEE, UPENDRA KUMAR PRADHAN, MRINMOY RAY, and OM PRAKASH. "Advanced row-column designs for animal feed experiments." Indian Journal of Animal Sciences 88, no. 4 (January 5, 2023): 499–503. http://dx.doi.org/10.56093/ijans.v88i4.78895.
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Inappropriate statistical designs may misinterpret results of animal feed experiments. Thus complete statistical designs can make animal feed research more appropriate and cost effective. Usually factorial row-column designs are used when the heterogeneity in the experimental material is in two directions and the experimenter is interested in studying the effect of two or more factors simultaneously. Attempts have been to develop the method of construction of balanced nested row column design under factorial setup. Factorial experiments are used in designs when two or more factors have same levels or different levels. The designs that are balanced symmetric factorials nested in blocks are called block designs with nested row-column balanced symmetric factorial experiments. These designs were constructed by using confounding through equation methods.Construction of confounded asymmetrical factorial experiments in row-column settings and efficiency factor of confounded effects was worked out. The design can be used in animal feed experiment with fewer resources by not compromising the test accuracy.
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Murray, Eleanor J., Ellen C. Caniglia, and Lucia C. Petito. "Causal survival analysis: A guide to estimating intention-to-treat and per-protocol effects from randomized clinical trials with non-adherence." Research Methods in Medicine & Health Sciences 2, no. 1 (October 8, 2020): 39–49. http://dx.doi.org/10.1177/2632084320961043.
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When reporting results from randomized experiments, researchers often choose to present a per-protocol effect in addition to an intention-to-treat effect. However, these per-protocol effects are often described retrospectively, for example, comparing outcomes among individuals who adhered to their assigned treatment strategy throughout the study. This retrospective definition of a per-protocol effect is often confounded and cannot be interpreted causally because it encounters treatment-confounder feedback loops, where past confounders affect future treatment, and current treatment affects future confounders. Per-protocol effects estimated using this method are highly susceptible to the placebo paradox, also called the “healthy adherers” bias, where individuals who adhere to placebo appear to have better survival than those who don’t. This result is generally not due to a benefit of placebo, but rather is most often the result of uncontrolled confounding. Here, we aim to provide an overview to causal inference for survival outcomes with time-varying exposures for static interventions using inverse probability weighting. The basic concepts described here can also apply to other types of exposure strategies, although these may require additional design or analytic considerations. We provide a workshop guide with solutions manual, fully reproducible R, SAS, and Stata code, and a simulated dataset on a GitHub repository for the reader to explore.
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C. Eze, Francis. "Choice of Confounding in the 2k Factorial Design in 2b Blocks." Academic Journal of Applied Mathematical Sciences, no. 55 (May 15, 2019): 50–56. http://dx.doi.org/10.32861/ajams.55.50.56.
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In 2k complete factorial experiment, the experiment must be carried out in a completely randomized design. When the numbers of factors increase, the number of treatment combinations increase and it is not possible to accommodate all these treatment combinations in one homogeneous block. In this case, confounding in more than one incomplete block becomes necessary. In this paper, we considered the choice of confounding when k > 2. Our findings show that the choice of confounding depends on the number of factors, the number of blocks and their sizes. When two more interactions are to be confounded, their product module 2 should be considered and thereafter, a linear combination equation should be used in allocating the treatment effects in the principal block. Other contents in other blocks are generated by multiplication module 2 of the effects not in the principal block. Partial confounding is recommended for the interactions that cannot be confounded.
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Soldner, Felix, Bennett Kleinberg, and Shane D. Johnson. "Confounds and overestimations in fake review detection: Experimentally controlling for product-ownership and data-origin." PLOS ONE 17, no. 12 (December 7, 2022): e0277869. http://dx.doi.org/10.1371/journal.pone.0277869.
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The popularity of online shopping is steadily increasing. At the same time, fake product reviews are published widely and have the potential to affect consumer purchasing behavior. In response, previous work has developed automated methods utilizing natural language processing approaches to detect fake product reviews. However, studies vary considerably in how well they succeed in detecting deceptive reviews, and the reasons for such differences are unclear. A contributing factor may be the multitude of strategies used to collect data, introducing potential confounds which affect detection performance. Two possible confounds are data-origin (i.e., the dataset is composed of more than one source) and product ownership (i.e., reviews written by individuals who own or do not own the reviewed product). In the present study, we investigate the effect of both confounds for fake review detection. Using an experimental design, we manipulate data-origin, product ownership, review polarity, and veracity. Supervised learning analysis suggests that review veracity (60.26–69.87%) is somewhat detectable but reviews additionally confounded with product-ownership (66.19–74.17%), or with data-origin (84.44–86.94%) are easier to classify. Review veracity is most easily classified if confounded with product-ownership and data-origin combined (87.78–88.12%). These findings are moderated by review polarity. Overall, our findings suggest that detection accuracy may have been overestimated in previous studies, provide possible explanations as to why, and indicate how future studies might be designed to provide less biased estimates of detection accuracy.
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Hillyard, Steven A. "Experimental Design Considerations in Studies of Event-Related Potentials to Word and Nonword Stimuli." Perceptual and Motor Skills 66, no. 1 (February 1988): 129–30. http://dx.doi.org/10.2466/pms.1988.66.1.129.
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A recent paper by Katayama and associates (1987) reported differences in late negative components of the event-related potentials to nonwords versus semantically deviant words in a randomized sequence. This comparison was confounded with differences in response requirements between the two stimulus classes.
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Sibbald, A. M., and L. J. F. Shellard. "The effect of stocking density on the grazing behaviour of sheep at the same herbage mass." Proceedings of the British Society of Animal Science 1998 (1998): 99. http://dx.doi.org/10.1017/s1752756200597518.
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It is well recognised that the grazing behaviour of sheep is influenced by the availability of vegetation (Hodgson, 1985). However, the extent to which grazing may also be influenced by social factors related to stocking density is not well understood, since stocking density and herbage availability are normally confounded. In this study an experimental design was used which, for the first time, allowed the effect of stocking density on grazing behaviour to be explored without being confounded with differences in herbage height or mass.
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Sibbald, A. M., and L. J. F. Shellard. "The effect of stocking density on the grazing behaviour of sheep at the same herbage mass." Proceedings of the British Society of Animal Science 1998 (1998): 99. http://dx.doi.org/10.1017/s0308229600033122.
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It is well recognised that the grazing behaviour of sheep is influenced by the availability of vegetation (Hodgson, 1985). However, the extent to which grazing may also be influenced by social factors related to stocking density is not well understood, since stocking density and herbage availability are normally confounded. In this study an experimental design was used which, for the first time, allowed the effect of stocking density on grazing behaviour to be explored without being confounded with differences in herbage height or mass.
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Wilczyńska, Kinga, and Grażyna Wieczorkowska. "Generational Differences in the Labour Market – Three Confounded Effects." Journal of Intercultural Management 14, no. 1 (March 1, 2022): 54–86. http://dx.doi.org/10.2478/joim-2022-0002.
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Abstract Objective: Many research claim that Millennials value work ethic much lower and leisure time much higher than older generations. Most of them are based on cross-sectional analyses of data collected at one time. This design confounds the COHORT effect (born in the same time period and thus exposed to the same cultural forces during their formative socialization period) and biological AGE, and it makes it impossible to separate them. Our goal is to demonstrate how to empirically separate the confounded effects of APC (biological AGE – PERIOD of measurement – COHORT) in a simple way. Methodology: Three generations (Baby Boomers, X-ers and Millennials) from the representative Polish samples of the World Value Survey, were cross-sectionally compared, and a cross-lagged comparison was made between BB in 2005 vs X in 2020, and between X in 2005 and Millennials in 2020. Findings: It was shown that significant cross-sectional differences in attitudes toward work between the 3 generation (with the highest score for Baby Boom-ers and the lowest for Millennials) cannot be explained by age differences. Over the period of 15 years, the importance of leisure time has increased for all generations (PERIOD effect). Value Added: The paper highlights significant methodological problem: the confounding effect of APC in most generational findings. It promotes the idea of using nationally representative samples from publicly available data like World Value Survey, instead of collecting convenience samples. Recommendations: Greater methodological rigour in generational studies is recommended, as their results can create/support stereotypes that tend to generate individual expectations (e.g. every Millennial is computer literate or lazy), ignoring the fact that intra-generational variability is very high.
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Mensah, Henry Kofi, Nestor Asiamah, and Kwame Mireku. "The effect of organizational justice delivery on organizational commitment." Journal of Global Responsibility 7, no. 2 (September 12, 2016): 196–209. http://dx.doi.org/10.1108/jgr-06-2016-0015.
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Purpose This study aims to examine the effect of organizational justice (OJ) delivery on organizational commitment (OC) while controlling variables that potentially confound this effect. These confound variable includes gender, education and tenure. Design/methodology/approach A causal quantitative field research and a cross-sectional research approach are used. A structured questionnaire is used to collect data from 463 randomly sampled employees of 13 commercial banks in Koforidua, Ghana. Structural equation modelling is used to analyze the data. Findings The study establishes that a statistically significant effect is made by OJ delivery on OC (p < 0.0001), even after controlling for the effects of gender, education and tenure. The model used also fits the data collected considerably (i.e. χ2 = 0.258; p-value = 0.611). Thus, the relationship between OJ and OC is not confounded by how long the employee has served on the job or by the highest educational level of employees. However, this relationship was significantly confounded by gender on the basis of sharing significant covariance with them. Originality/value Even though studies exist generally on OJ and OC, the focus on Ghana and banks in particular have been skeletal and have ended in testing just the relationship without highlighting the role of confounding variables as done in this study. Apart from adding to extant literature, findings will also inform decision-making on strategies and policies to improve OJ and ultimately the employee commitment that comes with.
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Das, Dipa Rani, and Sanjib Ghosh. "An Alternative Method of Construction and Analysis of Asymmetrical Factorial Experiment of the type 6x22 in Blocks of Size 12." Chittagong University Journal of Science 40, no. 1 (June 28, 2018): 137–50. http://dx.doi.org/10.3329/cujs.v40i1.47920.
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This paper focuses on the construction and analysis of an extra ordinary type of asymmetrical factorial experiment which corresponds to fraction of a symmetrical factorial experiment as indicated by Das (1960). For constructing this design, we have used 3 choices and for each choice we have used 5 different cases. Finding the block contents for each case we have seen that there are mainly two different cases for each choice. In case of analysis of variance, we have seen that, for the case where the highest order interaction effect is confounded in 4 replications, the loss of information is same for all the choices. Again for the case where the highest order interaction effect is confounded in 3 replications, the loss of information is also same for all the choices and one effect which is confounded due to fractionation has the same loss of information for all the choices.
The Chittagong Univ. J. Sci. 40 : 137-150, 2018
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Khan, Md Kamrul Hasan, and MA Jalil. "A General Method of Constructing Layout with Single Factorial Effect Confounded in pn Factorial Experiments." Dhaka University Journal of Science 62, no. 2 (February 8, 2015): 109–13. http://dx.doi.org/10.3329/dujs.v62i2.21974.
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A general method of constructing layout with single factorial effect confounded in pn factorial experiments is proposed. It becomes easier to construct the design of confounding a single factor in a pn factorial experiment, especially when the number of factors as well as the number of levels becomes larger. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21974 Dhaka Univ. J. Sci. 62(2): 109-113, 2014 (July)
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Huey, Beverly Messick, and Deborah A. Boehm-Davis. "Individual Differences in the Performance of a Process Control Task." Proceedings of the Human Factors Society Annual Meeting 36, no. 12 (October 1992): 897–901. http://dx.doi.org/10.1518/107118192786750322.
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The allocation of functions and tasks to humans and machines is seldom considered as a step in system design. In those cases where function allocation is considered, it is usually based on fixed schemes for all operators; however, it is possible that the optimal allocation scheme is not the same across individuals. In this research, two studies employed a pasteurizing plant simulation to investigate the effect of gender, age, education, and experience on system performance. Results of the first study revealed individual differences between males and females. However, gender was confounded with education and age. Because this confound could not be removed with the available subject pool, a second study was conducted to separate the effects of age and education on performance. In this latter study, analyses revealed significant individual difference on performance. These data suggest that individual difference variables need to be examined more fully in the system design process.
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Valliere, Dave. "The comparative state of entrepreneurial intent in Cameroon." Journal of Entrepreneurship in Emerging Economies 7, no. 3 (September 7, 2015): 241–55. http://dx.doi.org/10.1108/jeee-03-2015-0022.
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Purpose – This paper aims to report on the level of entrepreneurial intent (EI) in southwestern Cameroon, by developing and using a novel scale that avoids the problems of construct confounds that exist with most EI scales currently in the literature. This scale is also used to measure EI in Canada, as a comparative example of the Western countries typical of previous EI research, to demonstrate the stability of the scale across different cultures. Design/methodology/approach – Data are collected by survey of random participants in Jamaica and Canada. Factor analysis is used to refine the choice of scale elements from this survey. Nested structural equation modelling is then used to confirm the construct validity and to demonstrate construct stability across the two populations. The population scores are then compared by t-test. Findings – A novel ten-item scale is developed and is shown to have a stable factor structure across the two populations. Using this measure, it can be newly seen that, contrary to the expectations for low entrepreneurial prevalence and intention expressed in the literature, there is actually no significant EI deficit in Cameroon. Research limitations/implications – Previous measures of EI in the literature have been seriously confounded by adjacent constructs in the same nomological net, such as beliefs, attitudes and expectations for future behaviours. The research approach taken here demonstrates how these confounds may have led to erroneous conclusions about EI in Cameroon and potentially in other countries. The major limitation of this study is the small sample size, which should be reinforced by replication or extension in future studies. Originality/value – The development of a scale free of construct confounds represents an important step in the refinement of accurate measurement of this foundational construct in entrepreneurship research. This is underscored by the finding that EI in Cameroon may have been misreported in early research due to confounded measurement.
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Zolman, J. F. "Teaching experimental design to biologists." Advances in Physiology Education 277, no. 6 (December 1999): S111. http://dx.doi.org/10.1152/advances.1999.277.6.s111.
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The teaching of research design and data analysis to our graduate students has been a persistent problem. A course is described in which students, early in their graduate training, obtain extensive practice in designing experiments and interpreting data. Lecture-discussions on the essentials of biostatistics are given, and then these essentials are repeatedly reviewed by illustrating their applications and misapplications in numerous research design problems. Students critique these designs and prepare similar problems for peer evaluation. In most problems the treatments are confounded by extraneous variables, proper controls may be absent, or data analysis may be incorrect. For each problem, students must decide whether the researchers' conclusions are valid and, if not, must identify a fatal experimental flaw. Students learn that an experiment is a well-conceived plan for data collection, analysis, and interpretation. They enjoy the interactive evaluations of research designs and appreciate the repetitive review of common flaws in different experiments. They also benefit from their practice in scientific writing and in critically evaluating their peers' designs.
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Almond, Douglas, and Joseph J. Doyle. "After Midnight: A Regression Discontinuity Design in Length of Postpartum Hospital Stays." American Economic Journal: Economic Policy 3, no. 3 (August 1, 2011): 1–34. http://dx.doi.org/10.1257/pol.3.3.1.
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Estimates of moral hazard in health insurance markets can be confounded by adverse selection. This paper considers a plausibly exogenous source of variation in insurance coverage for childbirth in California. We find that additional health insurance coverage induces substantial extensions in length of hospital stay for mother and newborn. However, remaining in the hospital longer has no effect on readmissions or mortality, and the estimates are precise. Our results suggest that for uncomplicated births, minimum insurance mandates incur substantial costs without detectable health benefits. (JEL D82, G22, I12, I18, J13)
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Atzmüller, Christiane, and Peter M. Steiner. "Experimental Vignette Studies in Survey Research." Methodology 6, no. 3 (January 2010): 128–38. http://dx.doi.org/10.1027/1614-2241/a000014.
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Vignette studies use short descriptions of situations or persons (vignettes) that are usually shown to respondents within surveys in order to elicit their judgments about these scenarios. By systematically varying the levels of theoretically important vignette characteristics a large population of different vignettes is typically available – too large to be presented to each respondent. Therefore, each respondent gets only a subset of vignettes. These subsets may either be randomly selected in following the tradition of the factorial survey or systematically selected according to an experimental design. We show that these strategies in selecting vignette sets have strong implications for the analysis and interpretation of vignette data. Random selection strategies result in a random confounding of effects and heavily rely on the assumption of no interaction effects. In contrast, experimental strategies systematically confound interaction effects with main or set effects, thereby preserving a meaningful interpretation of main and important interaction effects. Using a pilot study on attitudes toward immigrants we demonstrate the implementation and analysis of a confounded factorial design.
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Gong, Stephen X. H., Michael Firth, and Kevin Cullinane. "Beta Estimation and Stability in the US-Listed International Transportation Industry." Review of Pacific Basin Financial Markets and Policies 09, no. 03 (September 2006): 463–90. http://dx.doi.org/10.1142/s0219091506000811.
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Although perceived as risk-laden, cyclical businesses with high financial and operating leverage, relatively low beta risks have been documented for the international transportation industry. This paper analyses whether such results are robust to different estimation designs and asserts that previous beta estimates are confounded by sample selection problems. Developing a more representative sample and implementing a number of different estimation designs, a range of industry beta estimates are derived. It is concluded that beta estimates of US-listed international transportation stocks are sensitive to estimation design and that industry beta risk is time-varying. This has implications for the industry cost of capital and pricing policies.
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Furukawa, Toshi A., Andrea Cipriani, Stefan Leucht, Lauren Z. Atkinson, Yusuke Ogawa, Nozomi Takeshima, Yu Hayasaka, Anna Chaimani, and Georgia Salanti. "Is placebo response in antidepressant trials rising or not? A reanalysis of datasets to conclude this long-lasting controversy." Evidence Based Mental Health 21, no. 1 (January 12, 2018): 1–3. http://dx.doi.org/10.1136/eb-2017-102827.
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It had long been believed that placebo response rates in antidepressant trials have been increasing and that they were responsible for rising numbers of so-called failed antidepressant trials. Two recent systematic reviews examined this issue and reached completely opposite findings. Furukawa and colleagues in a paper published in 2016 found that the placebo response rates are stable since 1991 and the apparent increase up to 2000 was confounded by changes in trial design features. By contrast, Khan and colleagues more recently concluded that placebo response rates had grown steadily in the past 30 years. The two reviews differed in the datasets they used, definitions of placebo response and statistical analyses. In this perspective article, we examined if such differences were responsible for the two reviews’ contrasting conclusions. Our reanalyses confirmed our previous results. We found that in any dataset and for any placebo response definition, there was no increase in placebo response over the years when the analysis was adjusted for the confounders related to study design features or when it was limited to studies published after 1990s. We conclude that placebo response in antidepressant trials has remained stable for the past 25 years, during which time the large majority of the studies have come to share similar design features.
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Robinson, Kay J., Edgar Chambers, and Barbara M. Gatewood. "Influence of Pattern Design and Fabric Type on the Hand Characteristics of Pigment Prints." Textile Research Journal 67, no. 11 (November 1997): 837–45. http://dx.doi.org/10.1177/004051759706701108.
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Two cotton fabrics printed with two pigment types in six designs have been analyzed by a trained descriptive panel to evaluate the effects of pattern design, color, and fabric type on seventeen hand characteristics. The six designs include a 3.2 mm wide stripe, a paisley, a 6.4 mm diameter dotted design, a 25.4 mm wide stripe, a modern swirl, and a check with 6.4 mm crossed stripes, and are printed on a 100% cotton shirting and an interlock knit with two print paste formulations that differ in pigment type (C.I. Pigment White 6 and C.I. Pigment Blue 15:3) and concentration. Results show that fabric and pigment type have a greater influence on hand characteristics than does the design of the print. However, the pattern design has a significant influence on eight of the seventeen components, but the effects are often confounded by the fabric-print paste combination. For many of the mechanical attributes, the dotted design has the highest intensity values, whereas the 25.4 mm stripe has the lowest. Thus, fabric type, print paste formulation, and pattern design need to be considered when evaluating the hand properties of pigment prints.
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Braniff, Nathan, Matthew Scott, and Brian Ingalls. "Component Characterization in a Growth-Dependent Physiological Context: Optimal Experimental Design." Processes 7, no. 1 (January 21, 2019): 52. http://dx.doi.org/10.3390/pr7010052.
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Synthetic biology design challenges have driven the use of mathematical models to characterize genetic components and to explore complex design spaces. Traditional approaches to characterization have largely ignored the effect of strain and growth conditions on the dynamics of synthetic genetic circuits, and have thus confounded intrinsic features of the circuit components with cell-level context effects. We present a model that distinguishes an activated gene’s intrinsic kinetics from its physiological context. We then demonstrate an optimal experimental design approach to identify dynamic induction experiments for efficient estimation of the component’s intrinsic parameters. Maximally informative experiments are chosen by formulating the design as an optimal control problem; direct multiple-shooting is used to identify the optimum. Our numerical results suggest that the intrinsic parameters of a genetic component can be more accurately estimated using optimal experimental designs, and that the choice of growth rates, sampling schedule, and input profile each play an important role. The proposed approach to coupled component–host modelling can support gene circuit design across a range of physiological conditions.
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Lam, Janine R., Jessica Tyler, Katrina J. Scurrah, Nicola J. Reavley, and Gillian S. Dite. "The Association between Socioeconomic Status and Psychological Distress: A Within and Between Twin Study." Twin Research and Human Genetics 22, no. 5 (October 2019): 312–20. http://dx.doi.org/10.1017/thg.2019.91.
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AbstractLow socioeconomic status (SES) has been established as a risk factor for poor mental health; however, the relationship between SES and mental health problems can be confounded by genetic and environmental factors in standard regression analyses and observational studies of unrelated individuals. In this study, we used a within-pair twin design to control for unmeasured genetic and environmental confounders in investigating the association between SES and psychological distress. We also employed within–between pair regression analysis to assess whether the association was consistent with causality. SES was measured using the Index of Relative Socio-economic Disadvantage (IRSD), income and the Australian Socioeconomic Index 2006 (AUSEI06); psychological distress was measured using the Kessler 6 Psychological Distress Scale (K6). Data were obtained from Twins Research Australia’s Health and Lifestyle Questionnaire (2014–2017), providing a maximum sample size of 1395 pairs. Twins with higher AUSEI06 scores had significantly lower K6 scores than their co-twins after controlling for shared genetic and environmental traits (βW [within-pair regression coefficient] = −0.012 units, p = .006). Twins with higher income had significantly lower K6 scores than their co-twins after controlling for familial confounders (βW = −0.182 units, p = .002). There was no evidence of an association between the IRSD and K6 scores within pairs (βW, p = .6). Using a twin design to eliminate the effect of potential confounders, these findings further support the association between low SES and poor mental health, reinforcing the need to address social determinants of poor mental health, in addition to interventions targeted to individuals.
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Fletcher, Jr., Robert J., Leslie Ries, James Battin, and Anna D. Chalfoun. "The role of habitat area and edge in fragmented landscapes: definitively distinct or inevitably intertwined?This review is one of a series dealing with some aspects of the impact of habitat fragmentation on animals and plants. This series is one of several virtual symposia focussing on ecological topics that will be published in the Journal from time to time." Canadian Journal of Zoology 85, no. 10 (October 2007): 1017–30. http://dx.doi.org/10.1139/z07-100.
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Over the past few decades, much research has focussed on the effects of habitat area (i.e., patch size) and edges in fragmented landscapes. We review and synthesize the literature on area and edge effects to identify whether the ecological processes influenced by patch size and edge are distinct, to summarize evidence for the relative effect of each, and to discuss how estimating their independent effects may be accomplished in field studies. Area and edge directly influence ecological processes in distinct ways, yet indirect effects can be similar, making it difficult to isolate the effects of area and edge in nature. Many studies investigating both area and edge have been confounded in their design and (or) analysis (i.e., studies did not control for one potential effect while testing for the other). Nonconfounded studies have more frequently shown support for edge effects, and comparisons between nonconfounded and confounded studies suggest that some observed area effects could be explained by edge effects. We argue that by focussing on the fundamental processes directly influenced by area and edge, and by developing more rigorous study designs and analyses that isolate their relative influence, greater insight can be gained in future investigations on habitat loss and fragmentation.
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Schwichow, Martin, Martina Brandenburger, and Jens Wilbers. "Analysis of experimental design errors in elementary school: how do students identify, interpret, and justify controlled and confounded experiments?" International Journal of Science Education 44, no. 1 (January 2, 2022): 91–114. http://dx.doi.org/10.1080/09500693.2021.2015544.
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Gong, Tong, Bronwyn Brew, Arvid Sjölander, and Catarina Almqvist. "Towards non-conventional methods of designing register-based epidemiological studies: An application to pediatric research." Scandinavian Journal of Public Health 45, no. 17_suppl (July 2017): 30–35. http://dx.doi.org/10.1177/1403494817702339.
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Aims: Various epidemiological designs have been applied to investigate the causes and consequences of fetal growth restriction in register-based observational studies. This review seeks to provide an overview of several conventional designs, including cohort, case-control and more recently applied non-conventional designs such as family-based designs. We also discuss some practical points regarding the application and interpretation of family-based designs. Methods: Definitions of each design, the study population, the exposure and the outcome measures are briefly summarised. Examples of study designs are taken from the field of low birth-weight research for illustrative purposes. Also examined are relative advantages and disadvantages of each design in terms of assumptions, potential selection and information bias, confounding and generalisability. Kinship data linkage, statistical models and result interpretation are discussed specific to family-based designs. Results: When all information is retrieved from registers, there is no evident preference of the case-control design over the cohort design to estimate odds ratios. All conventional designs included in the review are prone to bias, particularly due to residual confounding. Family-based designs are able to reduce such bias and strengthen causal inference. In the field of low birth-weight research, family-based designs have been able to confirm a negative association not confounded by genetic or shared environmental factors between low birth weight and the risk of asthma. Conclusions: We conclude that there is a broader need for family-based design in observational research as evidenced by the meaningful contributions to the understanding of the potential causal association between low birth weight and subsequent outcomes.
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Alexander, Corinne, Rachael E. Goodhue, and Gordon C. Rausser. "Do Incentives for Quality Matter?" Journal of Agricultural and Applied Economics 39, no. 1 (April 2007): 1–15. http://dx.doi.org/10.1017/s1074070800022719.
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We use an unusual dataset involving 14 tomato growers over 4 years to analyze the effect of incentive contracts on behavior in a fixed effects econometric model. We find that growers respond to incentive contracts by improving tomato quality, as predicted by economic theory. The comparison is not confounded by the usual contract endogeneity and simultaneity problems because of characteristics of the processing tomato industry and our dataset. We discuss the implications of our findings for the design of agricultural contracts.
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Jak, Suzanne, Terrence D. Jorgensen, and Yves Rosseel. "Evaluating Cluster-Level Factor Models with lavaan and Mplus." Psych 3, no. 2 (May 31, 2021): 134–52. http://dx.doi.org/10.3390/psych3020012.
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Background: Researchers frequently use the responses of individuals in clusters to measure cluster-level constructs. Examples are the use of student evaluations to measure teaching quality, or the use of employee ratings of organizational climate. In earlier research, Stapleton and Johnson (2019) provided advice for measuring cluster-level constructs based on a simulation study with inadvertently confounded design factors. We extended their simulation study using both Mplus and lavaan to reveal how their conclusions were dependent on their study conditions. Methods: We generated data sets from the so-called configural model and the simultaneous shared-and-configural model, both with and without nonzero residual variances at the cluster level. We fitted models to these data sets using different maximum likelihood estimation algorithms. Results: Stapleton and Johnson’s results were highly contingent on their confounded design factors. Convergence rates could be very different across algorithms, depending on whether between-level residual variances were zero in the population or in the fitted model. We discovered a worrying convergence issue with the default settings in Mplus, resulting in seemingly converged solutions that are actually not. Rejection rates of the normal-theory test statistic were as expected, while rejection rates of the scaled test statistic were seriously inflated in several conditions. Conclusions: The defaults in Mplus carry specific risks that are easily checked but not well advertised. Our results also shine a different light on earlier advice on the use of measurement models for shared factors.
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Drapeau, Aline, Alain Lesage, and Richard Boyer. "Is the Statistical Association between Sex and the Use of Services for Mental Health Reasons Confounded or Modified by Social Anchorage?" Canadian Journal of Psychiatry 50, no. 10 (August 1, 2005): 599–604. http://dx.doi.org/10.1177/070674370505001005.
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Objective: Confounding and interaction have differing implications for the interpretation of findings and the design of research, mental health services, and policy. This study aimed to verify whether the association between sex and the use of services for mental health reasons is confounded or modified by social anchorage. Methods: We undertook a case–control study nested in Cycle 1.2 of the Canadian Community Health Survey. Cases were defined as users of general medical services for mental health reasons in the previous 12 months, and control subjects were defined as never-users of any services for mental health reasons. The pattern of social anchorage was described by the roles of parent, spouse, worker, and their combination. Results: Overall, women are 2.9 times more likely than men to use general services for mental health reasons. However, this inequality between women and men decreases substantially or subsides in individuals who are less anchored to Canadian society. For instance, in single parents and in unemployed parents, the odds of using general services for mental health reasons are similar in women and in men. The pattern of social anchorage tends to modify, but not to confound, the association between sex and the use of services. Conclusions: Ignoring the interaction between sex and the pattern of social anchorage distorts the interpretation of the inequality between women and men in the use of general medical services for mental health reasons and may affect the design of comprehensive mental health services and policy.
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Tichopad, Ales, Rob Kitchen, Irmgard Riedmaier, Christiane Becker, Anders Ståhlberg, and Mikael Kubista. "Design and Optimization of Reverse-Transcription Quantitative PCR Experiments." Clinical Chemistry 55, no. 10 (October 1, 2009): 1816–23. http://dx.doi.org/10.1373/clinchem.2009.126201.
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Abstract Background: Quantitative PCR (qPCR) is a valuable technique for accurately and reliably profiling and quantifying gene expression. Typically, samples obtained from the organism of study have to be processed via several preparative steps before qPCR. Method: We estimated the errors of sample withdrawal and extraction, reverse transcription (RT), and qPCR that are introduced into measurements of mRNA concentrations. We performed hierarchically arranged experiments with 3 animals, 3 samples, 3 RT reactions, and 3 qPCRs and quantified the expression of several genes in solid tissue, blood, cell culture, and single cells. Results: A nested ANOVA design was used to model the experiments, and relative and absolute errors were calculated with this model for each processing level in the hierarchical design. We found that intersubject differences became easily confounded by sample heterogeneity for single cells and solid tissue. In cell cultures and blood, the noise from the RT and qPCR steps contributed substantially to the overall error because the sampling noise was less pronounced. Conclusions: We recommend the use of sample replicates preferentially to any other replicates when working with solid tissue, cell cultures, and single cells, and we recommend the use of RT replicates when working with blood. We show how an optimal sampling plan can be calculated for a limited budget. .
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Price, James J., Tingge Xu, Binwei Zhang, Lin Lin, Karl W. Koch, Eric L. Null, Kevin B. Reiman, et al. "Nanoindentation Hardness and Practical Scratch Resistance in Mechanically Tunable Anti-Reflection Coatings." Coatings 11, no. 2 (February 12, 2021): 213. http://dx.doi.org/10.3390/coatings11020213.
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This work presents fundamental understanding of the correlation between nanoindentation hardness and practical scratch resistance for mechanically tunable anti-reflective (AR) hardcoatings. These coatings exhibit a unique design freedom, allowing quasi-continuous variation in the thickness of a central hardcoat layer in the multilayer design, with minimal impact on anti-reflective optical performance. This allows detailed study of anti-reflection coating durability based on variations in hardness vs. depth profiles, without the durability results being confounded by variations in optics. Finite element modeling is shown to be a useful tool for the design and analysis of hardness vs. depth profiles in these multilayer films. Using samples fabricated by reactive sputtering, nanoindentation hardness depth profiles were correlated with practical scratch resistance using three different scratch and abrasion test methods, simulating real world scratch events. Scratch depths from these experiments are shown to correlate to scratches observed in the field from consumer electronics devices with chemically strengthened glass covers. For high practical scratch resistance, coating designs with hardness >15 GPa maintained over depths of 200–800 nm were found to be particularly excellent, which is a substantially greater depth of high hardness than can be achieved using previously common AR coating designs.
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Alix-Garcia, Jennifer, Sarah Walker, Volker Radeloff, and Jacek Kozak. "Tariffs and Trees: The Effects of the Austro-Hungarian Customs Union on Specialization and Land-Use Change." Journal of Economic History 78, no. 4 (October 2, 2018): 1142–78. http://dx.doi.org/10.1017/s0022050718000554.
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This article examines the impact of the 1850 Austro-Hungarian customs union on production land-use outcomes. Using newly digitized data from the Second Military Survey of the Habsburg Monarchy, we apply a spatial discontinuity design to estimate the impact of trade liberalization on land use. We find that the customs union increased cropland area by 8 percent per year in Hungary between 1850 and 1855, while forestland area decreased by 6 percent. We provide suggestive evidence that this result is not confounded by the emancipation of the serfs, population growth, or technological change in agriculture.
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Walters, Julie Lynette, Shylie Mackintosh, and Lorraine Sheppard. "Expectations Confounded: Patients Are Satisfied with THR and TKR Delivery in Australian Public Hospitals—A Multisite Case Study." ISRN Public Health 2012 (December 4, 2012): 1–6. http://dx.doi.org/10.5402/2012/947828.
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Background. The popular media infer that satisfaction with waiting lists for total hip or knee replacement surgery is poor; however, there is little supporting evidence for this. The purpose of this study was to describe patients satisfaction with the service they received for joint replacement surgery in a public hospital. Methods. A cross-sectional design was used to survey 450 patients. Data was analysed descriptively and chi-squared analyses (significance level of P<0.05) were used to examine associations between variables. Results. The response rate was 71%. Nearly three-quarters (n=312) of the sample were “very happy” with the service and 92.0% (n=379) indicated that they would have their surgery again. Satisfaction was significantly associated with waiting time to the first appointment (chi-square; P=0.002), whether the patients enquired about their waiting time (chisquare; P=0.003), and the number of preoperative appointments (chisquare; P=0.04). Most participants reported a maximum acceptable waiting period for initial appointment of less than 6 months but nearly half waited longer. Conclusions. The perception that patients are unhappy with elective surgery services in Australia may be unfounded despite many waiting longer than they consider appropriate.
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Weinschenk, Aaron C., and Christopher T. Dawes. "The Effect of Education on Political Knowledge: Evidence From Monozygotic Twins." American Politics Research 47, no. 3 (July 20, 2018): 530–48. http://dx.doi.org/10.1177/1532673x18788048.
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Political scientists have long been interested in the determinants of political knowledge. In many studies, education is the strongest predictor of political knowledge. However, some studies have found that education has no effect on knowledge once confounding variables are taken into account. In addition, some recent work suggests that education remains the strongest predictor of knowledge even after accounting for confounders like personality traits and intelligence. We provide new evidence on the effect of education on political knowledge by utilizing the co-twin control design. By looking at the relationship between education and knowledge within monozygotic twin pairs, we are able to circumvent sources of confounding of the relationship due to genetic factors and early-life family environment because monozygotic twins share both. We find that the relationship between education and political knowledge is highly confounded by genes and/or familial environment. The results from a naive model that does not take into account unobserved family factors indicate that education has a positive and statistically significant effect on political knowledge. However, in a twin fixed-effects model that accounts for confounding due to genetic factors and familial socialization, we find that the effect of education on political knowledge drops substantially and is not statistically significant at conventional levels.
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Glover, John A., Joan Rankin, Nancy Langner, Cathy Todero, and Dale Dinnel. "Memory for Sentences and Prose: Levels-of-Processing or Transfer-Appropriate-Processing?" Journal of Reading Behavior 17, no. 3 (September 1985): 215–34. http://dx.doi.org/10.1080/10862968509547541.
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Four experiments were conducted in order to contrast the levels-of-processing perspective with the transfer-appropriate-processing perspective. Experiment 1 employed a within-groups design to contrast the effects of various types of questions at different positions on subjects' recognition of sentences. The results seemed to support the transfer-appropriate-processing perspective's predictions but were confounded by the form of design. Experiment 2 examined the same questions with a between-groups design, while Experiment 3 replicated Experiment 2 with the use of a free recall posttest. The results of both Experiments 2 and 3 seemed to support the predictions of the transfer-appropriate-processing perspective and disconfirm the predictions of the levels-of-processing framework. Experiment 4 extended the work to subjects' memory for paragraphs. The results of Experiment 4, however, did not match the pattern observed in Experiments 1–3 and, instead, seemed to bear out the predictions of the levels-of-processing perspective. The results are discussed in terms of the influence of experimental design, choice of study materials, choice of dependent variables, and their interaction.
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Mondraty, Naresh, C. Laird Birmingham, Stephen Touyz, Viktoria Sundakov, Lucy Chapman, and Pierre Beumont. "Randomized Controlled Trial of Olanzapine in the Treatment of Cognitions in Anorexia Nervosa." Australasian Psychiatry 13, no. 1 (March 2005): 72–75. http://dx.doi.org/10.1080/j.1440-1665.2004.02154.x.
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Objective: Recovery from anorexia nervosa is confounded by intrusive anorec-tic cognitions and rituals. It has been observed that olanzapine, an atypical antipsychotic, can reduce this anorexic rumination. A pilot study was designed to test the effectiveness of olanzapine in this role. Methods: A randomized trial of olanzapine versus chlorpromazine, with anorexic rumination as the primary outcome, was conducted. Of the 26 patients who presented, 15 were randomized in a balanced block design, eight to olanzapine and seven to chlorpromazine. Results: Only the olanzapine group had a significant reduction in the degree of rumination. Conclusion: Olanzapine may be of benefit in anorexia nervosa by causing a reduction in anorexic rumination.
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Dincer, Demet, Thea Brejzek, and Lawrence Wallen. "Designing the Threshold: A Close Reading of Olafur Eliasson’s Approach to ‘Inside’ and ‘Outside’." Interiority 2, no. 1 (January 30, 2019): 43–61. http://dx.doi.org/10.7454/in.v2i1.48.
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This article discusses Icelandic installation artist Olafur Eliasson’s approach of the threshold as a productive liminal space rather than as a static boundary between the inside and the outside. Often defined as the physical division between the interior and the exterior in architecture, the authors argue that by looking at Eliasson’s works in detail, the threshold’s inherent capacity of comprising a dynamic dialogue between inside and outside where one is determined by the other unfolds. This paper proposes that designing the relationships between inside and outside involves subtle renegotiations and redefinitions of conventionalised notions of their boundaries and a resultant emergence of new design strategies.
Eliasson designs thresholds in diverse ways that he analyses and provokes the spatial associations between inside and outside, interior and exterior. While in Eliasson`s work the categories of inside and outside remain mutually exclusive, they physically co-exist at the same time; deliberately refracted, juxtapositioned, connected or confounded in an experimental yet rigorous approach that employs different scales and common characteristics. Seventeen of his works are analysed and grouped into four different threshold design strategies that result in an object, an association, an event and an immersive space.
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Rosa, Guilherme J. M., Natalia de Leon, and Artur J. M. Rosa. "Review of microarray experimental design strategies for genetical genomics studies." Physiological Genomics 28, no. 1 (December 2006): 15–23. http://dx.doi.org/10.1152/physiolgenomics.00106.2006.
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Genetical genomics approaches provide a powerful tool for studying the genetic mechanisms governing variation in complex traits. By combining information on phenotypic traits, pedigree structure, molecular markers, and gene expression, such studies can be used for estimating heritability of mRNA transcript abundances, for mapping expression quantitative trait loci (eQTL), and for inferring regulatory gene networks. Microarray experiments, however, can be extremely costly and time consuming, which may limit sample sizes and statistical power. Thus it is crucial to optimize experimental designs by carefully choosing the subjects to be assayed, within a selective profiling approach, and by cautiously controlling systematic factors affecting the system. Also, a rigorous strategy should be used for allocating mRNA samples across assay batches, slides, and dye labeling, so that effects of interest are not confounded with nuisance factors. In this presentation, we review some selective profiling strategies for genetical genomics studies, including the selection of individuals for increased genetic dissimilarity and for a higher number of recombination events. Efficient designs for studying epistasis are also discussed, as well as experiments for inferring heritability of transcriptional levels. It is shown that solving an optimal design problem generally requires a numerical implementation and that the optimality criteria should be intimately related to the goals of the experiment, such as the estimation of additive, dominance, and interacting effects, localizing putative eQTL, or inferring genetic and environmental variance components associated with transcriptional abundances.
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Tan, Justin. "Culture, Nation, and Entrepreneurial Strategic Orientations: Implications for an Emerging Economy." Entrepreneurship Theory and Practice 26, no. 4 (July 2002): 95–111. http://dx.doi.org/10.1177/104225870202600406.
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Since most researchers use the terms “culture” and “nation” interchangeably, the majority of empirical cross-cultural studies aiming to isolate the role of culture tend to be cross-national studies that are confounded with the influence of the national environment. This study employs a hybrid, quasi-experimental design to Investigate whether the cultural or national effects have a stronger influence on entrepreneurs' perception of the environment and their strategic orientations. Specifically, I draw on three samples of entrepreneurs from two cultures and two countries, namely, mainland Chinese, Chinese Americans, and Caucasian Americans. Such a quasi-experimental design allows us to better isolate the role of culture. Compared with the cultural effect, the national effect is more influential. In light of China's emerging economy in which entrepreneurship figures prominently, these findings point to the importance of institution-building efforts that foster a more entrepreneur-friendly national environment.
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Glowacz, Fabienne, Julie Léonard, and Audrey Courtain. "Pathways of Running Away Among Belgian Youth." Youth & Society 52, no. 2 (October 6, 2017): 143–65. http://dx.doi.org/10.1177/0044118x17734233.
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Runaway behaviors among teenagers have been studied for some 40 years. Still, because runaway and homeless youths have often been confounded, little is known about what really defines a runaway adolescent. This study targets three objectives in a mixed-method design relying on data from official files and interviews: the descriptions of teenagers reported as missing (e.g., age, sex, runaway duration and reiteration, place left behind, type of caller reporting the child as missing, motivation for closing the file) and the understanding of runaway pathways and dynamics. These studies can contribute to prevention and intervention programs by providing new perspectives on how runaway experiences should be understood in light of the adolescent process.
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Vercellotti, Mary Lou. "Do interactive learning spaces increase student achievement? A comparison of classroom context." Active Learning in Higher Education 19, no. 3 (October 27, 2017): 197–210. http://dx.doi.org/10.1177/1469787417735606.
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Research on interactive learning space classrooms has reported that instructors and students find them engaging, and engagement is expected to increase learning outcomes. Positive findings about interactive classrooms, though, are often confounded with active learning pedagogy since instructors who teach in interactive classrooms tend to also promote active learning pedagogy. More research is needed to tease apart learning gains from the instructional design, classroom context, and the related incorporation of technology. This study examined the relationship between learning gains and classroom context (traditional and interactive learning space) in a pretest/posttest design and reviewed student survey responses about learning experiences. Participants were enrolled in one of two sections of a course. Both groups were taught by the same instructor using active learning pedagogy with the same activities, materials, and assignments. The results showed that classroom context did not result in differences in students learning overall. Some findings pointing to subtle differences, however, indicate that the interactive classroom could have made the classroom instruction more effective and efficient.
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Bates, Timothy C., Brion S. Maher, Sarah E. Medland, Kerrie McAloney, Margaret J. Wright, Narelle K. Hansell, Kenneth S. Kendler, Nicholas G. Martin, and Nathan A. Gillespie. "The Nature of Nurture: Using a Virtual-Parent Design to Test Parenting Effects on Children's Educational Attainment in Genotyped Families." Twin Research and Human Genetics 21, no. 2 (March 13, 2018): 73–83. http://dx.doi.org/10.1017/thg.2018.11.
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Research on environmental and genetic pathways to complex traits such as educational attainment (EA) is confounded by uncertainty over whether correlations reflect effects of transmitted parental genes, causal family environments, or some, possibly interactive, mixture of both. Thus, an aggregate of thousands of alleles associated with EA (a polygenic risk score; PRS) may tap parental behaviors and home environments promoting EA in the offspring. New methods for unpicking and determining these causal pathways are required. Here, we utilize the fact that parents pass, at random, 50% of their genome to a given offspring to create independent scores for the transmitted alleles (conventional EA PRS) and a parental score based on allelesnot transmittedto the offspring (EA VP_PRS). The formal effect of non-transmitted alleles on offspring attainment was tested in 2,333 genotyped twins for whom high-quality measures of EA, assessed at age 17 years, were available, and whose parents were also genotyped. Four key findings were observed. First, the EA PRS and EA VP_PRS were empirically independent, validating the virtual-parent design. Second, in this family-based design, children's own EA PRS significantly predicted their EA (β = 0.15), ruling out stratification confounds as a cause of the association of attainment with the EA PRS. Third, parental EA PRS predicted the SES environment parents provided to offspring (β = 0.20), and parental SES and offspring EA were significantly associated (β = 0.33). This would suggest that the EA PRS is at least as strongly linked to social competence as it is to EA, leading to higher attained SES in parents and, therefore, a higher experienced SES for children. In a full structural equation model taking account of family genetic relatedness across multiple siblings the non-transmitted allele effects were estimated at similar values; but, in this more complex model, confidence intervals included zero. A test using the forthcoming EA3 PRS may clarify this outcome. The virtual-parent method may be applied to clarify causality in other phenotypes where observational evidence suggests parenting may moderate expression of other outcomes, for instance in psychiatry.
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Wall, Gerard W., and Guy McDonnell. "Rapid Excision Apparatus for Plants (REAPer): Design, Implementation, and Functionality." HortScience 38, no. 2 (April 2003): 207–11. http://dx.doi.org/10.21273/hortsci.38.2.207.
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Net primary productivity of a botanical is often determined by monitoring gas exchange rates (i.e., CO2, H2O) in a controlled-environment cuvette. Because atmospheric conditions (i.e., incident photon flux density, air temperature, and water vapor pressure) change within a day, whereas edaphic (i.e., soil-water content and nutrient availability) conditions change across days, experimental results obtained between treatment variants can often be confounded within the sample interval. Consequently, in order to obtain a “snapshot” of the CO2 and H2O flux of a botanical across treatment variants, all in situ measurements must be made within a discrete interval. One approach would be to use multiple cuvettes to measure CO2 and H2O flux across all treatment variants simultaneously. But, this would be expensive in both equipment and personnel cost. A more economical approach would be to rapidly excise a botanical from each treatment variant within a discrete interval and store them under exacting steady-state laboratory conditions for in vivo rather than in situ studies. However, this too can be problematic, because in order to excise a botanical a standard operating procedure (SOP) is required. Hence, a need exists for a Rapid Excision Apparatus for Plants (REAPer). Following the SOP of the REAPer enables personnel to excise a botanical across all treatment variants within a discrete interval, while maintaining xylem conductance, minimizing mechanical damage, and providing a uniform sample for in vivo rather then in situ studies. This work describes the design, implementation, and functionality of the REAPer, its application in basic research and development, and its potential applications in the commercial floral and horticultural industries.
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Goodall, Tracy A., W. Kim Halford, and Robin Mortimer. "Problem Solving Training to Enhance Dietary Self-management in a Diabetic Patient." Behavioural Psychotherapy 21, no. 2 (April 1993): 147–55. http://dx.doi.org/10.1017/s0141347300018115.
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A central aspect of self-management of diabetes involves patients regulating the timing and intake of dietary carbohydrates. A 20 year old female diabetic patient was taught to identify deviations from appropriate dietary self-management, and a problem solving intervention was used to train new behavior in settings associated with such deviations. Dietary behavior and blood glucose levels were monitored in a diary and electronically, and treatment effects were evaluated in a multiple baseline across settings design. Treatment resulted in clear improvement in dietary management, and a substantial gain in blood glucose control at the end of intervention. At follow-up dietary change was maintained. Long term effects on blood glucose levels were confounded by a reduction in insulin dosage between treatment and follow-up.
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Gilad, Yoav, and Orna Mizrahi-Man. "A reanalysis of mouse ENCODE comparative gene expression data." F1000Research 4 (May 19, 2015): 121. http://dx.doi.org/10.12688/f1000research.6536.1.
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Recently, the Mouse ENCODE Consortium reported that comparative gene expression data from human and mouse tend to cluster more by species rather than by tissue. This observation was surprising, as it contradicted much of the comparative gene regulatory data collected previously, as well as the common notion that major developmental pathways are highly conserved across a wide range of species, in particular across mammals. Here we show that the Mouse ENCODE gene expression data were collected using a flawed study design, which confounded sequencing batch (namely, the assignment of samples to sequencing flowcells and lanes) with species. When we account for the batch effect, the corrected comparative gene expression data from human and mouse tend to cluster by tissue, not by species.